Session 6 prep questions
what 4 classes of antibiotics work to inhibit translation in bacteria?
Aminoglycosides: Examples include gentamicin, streptomycin, and neomycin. They bind to the 30S ribosomal subunit and interfere with the initiation of protein synthesis, causing misreading of mRNA and ultimately inhibiting translation. Tetracyclines: Examples include tetracycline, doxycycline, and minocycline. They bind to the 30S ribosomal subunit and inhibit the binding of aminoacyl-tRNA to the ribosome, thereby blocking protein synthesis. Macrolides: Examples include erythromycin, clarithromycin, and azithromycin. They bind to the 50S ribosomal subunit and inhibit the translocation step of protein synthesis, preventing the elongation of the polypeptide chain. Chloramphenicol: This antibiotic binds to the 50S ribosomal subunit and inhibits the peptidyl transferase activity, which is essential for peptide bond formation during protein synthesis. These antibiotics target different steps of the bacterial translation process, leading to inhibition of protein synthesis and ultimately impairing bacterial growth and survival.
of E. coli, Salmonella, and shigella, which one(s) are motile?
Among Escherichia coli, Salmonella spp., and Shigella spp., only Escherichia coli is typically motile. E. coli is a Gram-negative bacterium that possesses flagella, which are whip-like structures that enable motility. This motility allows E. coli to move towards favorable environments and nutrients. Salmonella spp. and Shigella spp. are also Gram-negative bacteria, but they are generally non-motile. While some strains of Salmonella may exhibit motility under specific conditions, most strains are non-motile. Similarly, Shigella spp. are non-motile bacteria.
what is the vector and causative agent of chagas disease?
Chagas disease, also known as American trypanosomiasis, is caused by the protozoan parasite Trypanosoma cruzi. The vector responsible for transmitting Chagas disease is primarily the triatomine bug, also known as the "kissing bug" or "assassin bug." These insects typically feed on the blood of mammals, including humans, and can transmit the parasite to humans through their feces. When an infected bug bites a person, it may defecate near the bite wound, allowing the parasite to enter the body through mucous membranes or breaks in the skin. Additionally, transmission can occur through blood transfusion, organ transplantation, congenital transmission (from mother to child during pregnancy), and ingestion of contaminated food or drink.
compare chickenpox and smallpox in terms of synchrony/asynchrony between lesion evolution
Chickenpox (Varicella): Asynchronous Lesion Evolution: In chickenpox, the lesions typically appear in crops over several days. This means that new lesions continue to appear while older ones are still in various stages of healing. Therefore, the lesions are asynchronous in their evolution. Characteristics: Chickenpox lesions start as small red spots and progress to fluid-filled vesicles before crusting over. At any given time, there are lesions in different stages of development, from macules to papules to vesicles and crusts. Smallpox (Variola): Synchronous Lesion Evolution: In smallpox, the lesions tend to evolve more synchronously. They appear almost simultaneously and progress through similar stages of development at roughly the same rate. This synchronous evolution is a key diagnostic feature of smallpox. Characteristics: Smallpox lesions develop in a more uniform manner. They start as raised red spots (macules) that progress to fluid-filled vesicles (pustules) before crusting over. Since the lesions appear almost simultaneously, they are more synchronous in their evolution compared to chickenpox.
what is the mechanism of action for killing plasmodium by chloroquine?...by Primaquine?
Chloroquine: Chloroquine primarily acts by inhibiting the polymerization of heme into hemozoin within the digestive vacuole of the Plasmodium parasite. Hemozoin is a crystalline byproduct of hemoglobin digestion by the parasite, and its formation is essential for detoxifying and sequestering toxic heme molecules generated during this process. By inhibiting hemozoin formation, chloroquine effectively accumulates toxic heme within the digestive vacuole, leading to oxidative damage and ultimately the death of the parasite. Additionally, chloroquine may also interfere with other cellular processes in Plasmodium parasites, such as inhibiting nucleic acid synthesis and disrupting membrane function. In summary, chloroquine primarily acts by inhibiting hemozoin formation, while primaquine exerts its antimalarial effects through the generation of reactive oxygen species and other mechanisms that disrupt essential metabolic processes in the parasite.
name the 4 types of prion disease?
Creutzfeldt-Jakob Disease (CJD): This is the most common form of prion disease in humans and can occur in sporadic, familial, or acquired forms. Sporadic CJD arises spontaneously, familial CJD is inherited, and acquired CJD can result from exposure to contaminated tissues or medical procedures. Variant Creutzfeldt-Jakob Disease (vCJD): vCJD is a distinct form of CJD that is thought to be caused by consumption of meat products contaminated with the prion associated with bovine spongiform encephalopathy (BSE), also known as mad cow disease. Gerstmann-Sträussler-Scheinker Syndrome (GSS): GSS is a rare familial form of prion disease characterized by slowly progressive neurological symptoms, including ataxia, dementia, and movement disorders. It is caused by mutations in the PRNP gene encoding the prion protein. Fatal Familial Insomnia (FFI): FFI is another rare familial form of prion disease characterized by progressive insomnia, dysautonomia, and eventually dementia. It is also caused by mutations in the PRNP gene. These prion diseases are characterized by the abnormal folding of the prion protein, leading to the accumulation of misfolded prions in the brain, neuronal damage, and the formation of characteristic spongiform changes. They typically result in rapidly progressive neurological decline and are ultimately fatal.
what stain is used to microscopically visualize cryptococcus?
Cryptococcus can be visualized microscopically using India ink staining. India ink staining is a simple and commonly used method to visualize encapsulated organisms such as Cryptococcus neoformans. In this staining technique, a small amount of India ink is mixed with a sample containing Cryptococcus cells. The ink particles act as a negative stain, outlining the capsules surrounding the Cryptococcus cells, which appear as clear halos against a dark background. This allows for the visualization of the characteristic encapsulated yeast cells of Cryptococcus under the microscope.
is cryptococcus a yeast or a mold?
Cryptococcus is a yeast. Specifically, it is an encapsulated yeast belonging to the genus Cryptococcus. The most clinically relevant species within this genus is Cryptococcus neoformans, which is an opportunistic pathogen capable of causing serious infections, particularly in immunocompromised individuals such as those with HIV/AIDS. Another species, Cryptococcus gattii, is also known to cause infections, primarily in immunocompetent individuals.
what is the basic molecular "type" (I.e. type of macromolecule) that comprises all exotoxins
Exotoxins are proteins, which means that the basic molecular "type" comprising all exotoxins is proteins. Exotoxins are produced by certain bacteria and are secreted into the surrounding environment or released upon bacterial lysis. These proteins can exert various harmful effects on host cells and tissues, contributing to the pathogenicity of the bacteria that produce them.
how does pathologically small ferguson's angle affect the curvature of the lumbar spine?
Ferguson's angle, also known as the lumbosacral angle, is an angle formed by lines drawn along the superior endplate of the sacrum and the horizontal plane. It is used as a measure of the curvature of the lumbar spine. A pathologically small Ferguson's angle typically indicates decreased lumbar lordosis, which is the natural inward curvature of the lumbar spine when viewed from the side. When Ferguson's angle is pathologically small, it suggests a reduction in the normal curvature of the lumbar spine, leading to a more flattened or straightened appearance of the lower back. This decreased lumbar lordosis can result from various conditions such as muscle imbalances, disc degeneration, spinal stenosis, or ankylosing spondylitis, among others. The reduction in lumbar lordosis can have biomechanical implications, potentially altering the distribution of forces along the spine and affecting posture, stability, and spinal function. It may also contribute to symptoms such as back pain, stiffness, and impaired mobility. Additionally, a pathologically small Ferguson's angle may be associated with compensatory changes in other regions of the spine, such as increased thoracic kyphosis (outward curvature of the upper back), in an attempt to maintain overall spinal alignment and balance.
what is the vector for hantavirus? what body system is most affected by a hantavirus infection
Hantaviruses are primarily transmitted to humans through contact with rodents, particularly the urine, droppings, or saliva of infected rodents. The main vectors or reservoir hosts for hantaviruses are certain species of rodents, including deer mice, white-footed mice, cotton rats, and rice rats. In terms of the body system most affected by a hantavirus infection, hantaviruses primarily target the respiratory system. Hantavirus pulmonary syndrome (HPS), the most severe form of hantavirus infection in humans, is characterized by severe respiratory symptoms, including acute respiratory distress syndrome (ARDS), pulmonary edema, and respiratory failure. Hantaviruses can cause a sudden and severe respiratory illness, which can be life-threatening if not promptly diagnosed and treated. It's important to note that while the respiratory system is the primary target of hantaviruses, they can also affect other organ systems, leading to symptoms such as fever, muscle aches, headache, abdominal pain, and occasionally renal failure (especially in cases of Hantavirus Hemorrhagic Fever with Renal Syndrome, or HFRS, which is more common in Europe and Asia).
if a slide made from a vaginal swab is examined and germ tubes are pseudohyphae are noticed, what infection probably exists?
If a slide made from a vaginal swab shows germ tubes and pseudohyphae, it suggests the presence of Candida albicans. Candida albicans is a yeast fungus commonly found in the vaginal flora. Under certain conditions, such as a weakened immune system or changes in vaginal pH, Candida albicans can overgrow, leading to vaginal yeast infections (vulvovaginal candidiasis). The presence of germ tubes and pseudohyphae is characteristic of Candida albicans and can be observed in laboratory cultures or microscopic examination of clinical specimens, including vaginal swabs. These structures help differentiate Candida albicans from other Candida species and are indicative of invasive growth by the fungus.
If the Km of an enzyme is high, what is its affinity for the substrate? (how, low, or unknown)
If the Km (Michaelis constant) of an enzyme is high, it indicates that the enzyme has a low affinity for its substrate. Km is a measure of the substrate concentration at which the enzyme achieves half of its maximum reaction rate (Vmax). A high Km value means that a relatively high substrate concentration is required to achieve half of Vmax, indicating that the enzyme binds to its substrate less tightly and requires higher substrate concentrations to reach optimal catalytic activity. Conversely, a low Km value indicates high affinity, meaning that the enzyme binds tightly to its substrate and achieves half of Vmax at lower substrate concentrations. Therefore, if the Km is high, the enzyme's affinity for the substrate is low.
What PAS character do the mucosal macrophages of Whipple's disease patients have?
In Whipple's disease, the mucosal macrophages contain PAS-positive, diastase-resistant granules. PAS staining (Periodic Acid-Schiff staining) is commonly used to detect polysaccharides, glycogen, and mucopolysaccharides in tissues. In Whipple's disease, the PAS-positive granules within the macrophages represent accumulations of periodic acid-Schiff-positive glycoprotein material, which are characteristic histological findings of the disease. These granules are diastase-resistant, meaning they resist digestion by diastase, an enzyme that breaks down glycogen.
what is the causative agent of Kala-Azar? What is another name for this disease (colloquially)?
Kala-Azar, also known as visceral leishmaniasis, is caused by the protozoan parasite Leishmania donovani. Another colloquial name for Kala-Azar is "black fever." This name refers to the characteristic symptoms of the disease, including fever, weight loss, anemia, and enlargement of the spleen and liver, which can give the skin a dark or dusky appearance.
at what level does the spinal cord end in most people?
L1-L2
If a person is suffering from a herniated L3 intervertebral disc, what nerve root will be affected?
L4
what virus causes measles? German measles?
Measles, also known as rubeola, is caused by the measles virus, which belongs to the genus Morbillivirus within the family Paramyxoviridae. German measles, also known as rubella, is caused by the rubella virus, which belongs to the genus Rubivirus within the family Togaviridae.
PART 2*** what are the major types of spina bifida and what does each represent in terms of contents herniated?
Meningocele: In meningocele, there is a protrusion of the meninges (protective coverings of the spinal cord) through a defect in the vertebral column, forming a sac or cyst-like structure. However, the spinal cord itself remains intact and does not herniate into the sac. Meningoceles are typically covered by a layer of skin and may appear as a visible lump or swelling on the back. Depending on the size and location of the meningocele, individuals may or may not experience neurological symptoms. Myelomeningocele: Myelomeningocele is the most severe form of spina bifida, characterized by a protrusion of both the meninges and the spinal cord through an opening in the vertebral column. The exposed neural tissue is not covered by skin and is vulnerable to damage from trauma, infection, and exposure to amniotic fluid in utero. Myelomeningocele often results in significant neurological deficits, including paralysis, sensory loss, and bowel and bladder dysfunction. Surgical repair is typically required shortly after birth to protect the exposed neural tissue and prevent complications.
what enzyme does methotrexate inhibit? what effect does this have molecularly, in terms of what major product can no longer be produced?
Methotrexate inhibits the enzyme dihydrofolate reductase (DHFR). Dihydrofolate reductase is essential for the synthesis of tetrahydrofolate (THF) from dihydrofolate (DHF). Tetrahydrofolate serves as a cofactor in several biochemical reactions, including the synthesis of nucleotides (purines and pyrimidines), amino acids, and other important molecules. One of the major products that can no longer be produced when dihydrofolate reductase is inhibited by methotrexate is thymidylate (dTMP), which is a precursor for the synthesis of thymidine, a component of DNA. Inhibition of dihydrofolate reductase by methotrexate disrupts the production of THF, leading to decreased synthesis of dTMP and ultimately impairing DNA synthesis and cell proliferation. This effect is particularly relevant in rapidly dividing cells, such as cancer cells, which rely heavily on de novo nucleotide synthesis for DNA replication and cell division.
what similarity do methotrexate, trimethoprim, and pyrimethamine have in common in terms of mechanism of action?
Methotrexate, trimethoprim, and pyrimethamine share a common mechanism of action in that they all inhibit dihydrofolate reductase (DHFR), an enzyme involved in the synthesis of tetrahydrofolate (THF), which is essential for nucleotide synthesis. By inhibiting DHFR, these drugs interfere with the production of THF, leading to a depletion of nucleotide precursors required for DNA and RNA synthesis. This ultimately inhibits the growth and replication of cells, whether they are bacterial (in the case of trimethoprim) or mammalian (in the case of methotrexate and pyrimethamine). This shared mechanism of action makes these drugs useful for treating various conditions, including cancer (methotrexate), bacterial infections (trimethoprim), and parasitic infections (pyrimethamine).
what type of coxsackie virus is associated with myocarditis? with hand-foot-mouth disease?
Myocarditis is often associated with Coxsackievirus B, particularly serotypes B1-B6, with B3 being a common culprit. Hand-foot-mouth disease is primarily caused by Coxsackievirus A16, although other Coxsackievirus A serotypes and Enterovirus 71 can also be responsible.
What are the common contaminating agents/sources that frequently serve to contaminate bodies of water with Leptospira interrogans?
Overall, leptospirosis transmission is closely linked to environmental factors, including the presence of contaminated water sources, exposure to infected animals, and poor sanitation practices. Preventive measures, such as proper sanitation, rodent control, and avoidance of contact with contaminated water, are essential for reducing the risk of leptospirosis transmission.
what species of plasmodium is the most severe and life-threatening one?
Plasmodium falciparum is the species of Plasmodium that is the most severe and life-threatening. It is responsible for the majority of malaria-related deaths globally. Unlike other species of Plasmodium, P. falciparum can cause severe complications, including cerebral malaria, severe anemia, acute respiratory distress syndrome (ARDS), renal failure, and multi-organ failure. It has a high potential for rapid replication in the bloodstream, leading to high parasite burdens and severe disease manifestations. Additionally, P. falciparum has the ability to adhere to and sequester within small blood vessels, particularly in the brain, contributing to the development of cerebral malaria, which is associated with high mortality rates if not promptly treated.
is prader willi due to the maternal or paternal deletion of 15q 11-13 chromosome?
Prader-Willi syndrome (PWS) is typically due to the paternal deletion of the 15q11-13 region of chromosome 15. This deletion results in the loss of certain genes on the paternal chromosome 15, leading to the characteristic features of Prader-Willi syndrome. In contrast, Angelman syndrome, another genetic disorder with overlapping features, is typically due to the maternal deletion of the same region (15q11-13) of chromosome 15. This maternal deletion results in the loss of certain genes on the maternal chromosome 15, leading to the characteristic features of Angelman syndrome. Both Prader-Willi syndrome and Angelman syndrome are examples of imprinting disorders, where the expression of certain genes depends on whether they are inherited from the mother or the father. In Prader-Willi syndrome, there is a lack of expression of paternal genes in the 15q11-13 region, while in Angelman syndrome, there is a lack of expression of maternal genes in the same region.
what is the mechanism of action for killing plasmodium by chloroquine?...by Primaquine?
Primaquine: Primaquine has a different mechanism of action compared to chloroquine. Primaquine is a blood schizonticide, meaning it primarily acts against the parasite during its blood stage (as opposed to the liver stage). It is particularly effective against Plasmodium vivax and Plasmodium ovale, which can form dormant liver stages (hypnozoites) responsible for relapses. The exact mechanism of action of primaquine is not fully understood. However, it is believed to exert its antimalarial activity by generating reactive oxygen species (ROS) within the parasite, leading to oxidative damage to cellular components such as DNA, proteins, and lipids. This oxidative stress disrupts essential metabolic processes in the parasite, ultimately leading to its death. Primaquine may also interfere with other biochemical pathways in Plasmodium parasites, although the details of these interactions are still being elucidated. In summary, chloroquine primarily acts by inhibiting hemozoin formation, while primaquine exerts its antimalarial effects through the generation of reactive oxygen species and other mechanisms that disrupt essential metabolic processes in the parasite.
With what HLA type is psoriatic arthritis associated? What other diseases that we have discussed are also associated with this HLA type?
Psoriatic arthritis (PsA) is associated with several human leukocyte antigen (HLA) alleles, with the strongest association observed with HLA-B27. HLA-B27 is also strongly associated with ankylosing spondylitis (AS), which is a type of inflammatory arthritis primarily affecting the spine and sacroiliac joints. In addition to PsA and AS, HLA-B27 has also been linked to other diseases, including reactive arthritis (formerly known as Reiter's syndrome) and some forms of inflammatory bowel disease (IBD), such as Crohn's disease and ulcerative colitis. Overall, the association of HLA-B27 with PsA, AS, reactive arthritis, and certain forms of IBD suggests shared immunogenetic factors and potential overlapping pathogenic mechanisms among these conditions.
what type of disease or disorder does rotavirus cause? to what family does rotavirus belong?
Rotavirus primarily causes gastroenteritis, which is inflammation of the stomach and intestines, leading to symptoms such as diarrhea, vomiting, fever, and abdominal pain. It is a major cause of severe diarrhea in infants and young children worldwide, often leading to dehydration and hospitalization.
**PART 2**compare Schistosoma mansoni, Sch. japonicum, and sch. hematobium in terms of location of the veins in which they eventually settle
Schistosoma japonicum: Geographical Distribution: Schistosoma japonicum is predominantly found in parts of Asia, particularly in China, the Philippines, and Indonesia, where intermediate host snails of the Oncomelania genus are present. Vein Location: Schistosoma japonicum mainly settles in the mesenteric veins draining the intestines, similar to Schistosoma mansoni. It primarily affects the small intestine, including the ileum, and the large intestine. Schistosoma haematobium: Geographical Distribution: Schistosoma haematobium is commonly found in Africa and the Middle East, particularly in areas with freshwater bodies infested with intermediate host snails of the Bulinus genus. Vein Location: Schistosoma haematobium primarily settles in the venous plexus of the urinary bladder and ureters. Eggs laid by female worms penetrate the bladder wall and are excreted in urine, leading to urinary schistosomiasis. In summary, while all three species of Schistosoma settle in the veins draining internal organs, they have distinct preferences for the location of their final habitat within the body. Schistosoma mansoni and Schistosoma japonicum primarily settle in the mesenteric veins of the intestines, while Schistosoma haematobium primarily settles in the venous plexus of the urinary bladder and ureters.
compare Schistosoma mansoni, Sch. japonicum, and sch. hematobium in terms of location of the veins in which they eventually settle
Schistosoma mansoni, Schistosoma japonicum, and Schistosoma haematobium are parasitic trematodes (flukes) that cause schistosomiasis in humans. While they share similarities in their life cycles and clinical manifestations, there are differences in terms of their geographical distribution and the location of the veins in which they eventually settle: Schistosoma mansoni: Geographical Distribution: Schistosoma mansoni is primarily found in Africa and parts of South America, particularly in areas with freshwater bodies infested with intermediate host snails of the Biomphalaria genus. Vein Location: Schistosoma mansoni typically settles in the mesenteric veins draining the intestines, particularly the large intestine (colon and rectum). Eggs laid by female worms migrate through the intestinal wall and are excreted in feces.
what is the drug of choice for leishmaniasis?
Sodium stibogluconate, amphotericin B
what are the major types of spina bifida and what does each represent in terms of contents herniated?
Spina bifida refers to a group of congenital neural tube defects that occur when the neural tube, which forms the embryonic precursor to the spinal cord and vertebral column, fails to close properly during fetal development. Spina Bifida Occulta: This is the mildest and most common form of spina bifida. In spina bifida occulta, the spinal cord and meninges (protective coverings of the spinal cord) remain inside the spinal canal, and there is no herniation of neural tissue or meninges through the vertebral defect. However, there may be a small gap or opening in one or more vertebrae, usually in the lower lumbar or sacral region. Often, there are no noticeable symptoms or neurological deficits associated with spina bifida occulta, and the condition may only be detected incidentally on imaging studies performed for other reasons.
if a tissue of an infected area reveals microscopically, cigar shaped budding yeast, what is the most likely causative agent of that infection?
Sporothrix schenckii
List the different stages of plasmodial development from the time it is "injected" into the body by the mosquito to the time it is drawn out by another blood-sucking mosquito:
Sporozoite Stage: When an infected female Anopheles mosquito bites a human, it injects sporozoites into the bloodstream along with its saliva. Sporozoites are the infectious form of the parasite and quickly travel to the liver. Liver Stage (Hepatic Stage): Sporozoites invade hepatocytes (liver cells) and undergo a period of asexual reproduction called the exoerythrocytic phase. Inside hepatocytes, sporozoites mature into schizonts, which undergo multiple rounds of replication to produce thousands of merozoites. Blood Stage (Erythrocytic Stage): Merozoites are released from infected hepatocytes into the bloodstream, where they invade red blood cells (RBCs). Within RBCs, merozoites develop into ring-stage trophozoites, which mature into schizonts. Schizonts undergo multiple rounds of replication within RBCs, leading to the release of new merozoites. Some merozoites differentiate into male and female gametocytes, which can be taken up by a mosquito during a blood meal. Mosquito Stage: When an infected mosquito takes a blood meal, it ingests gametocytes along with the blood. Inside the mosquito's midgut, gametocytes mature into gametes (male and female). Fertilization occurs in the mosquito's midgut, forming zygotes. Zygotes develop into motile ookinetes, which penetrate the midgut wall and form oocysts on the outer surface of the midgut. Oocysts mature and release thousands of sporozoites into the mosquito's hemolymph. Sporozoites migrate to the mosquito's salivary glands, where they can be injected into a human host during a subsequent blood meal, restarting the lifecycle. This cyclical process continues, perpetuating the transmission of malaria from mosquitoes to humans and back again.
what is the causative agent of subacute sclerosing panencephalitis?
Subacute sclerosing panencephalitis (SSPE) is caused by a persistent infection of the brain with a defective form of the measles virus (also known as the subacute sclerosing panencephalitis virus). This defective virus is characterized by mutations that allow it to evade the immune system and persist in the brain for years after the initial measles infection. Over time, the persistent measles virus infection leads to progressive inflammation and degeneration of the brain, resulting in the characteristic neurological symptoms of SSPE.
in what dermatome does the umbilicus lie?
T10
why is takayasu disease called the "pulseless disease"?
Takayasu arteritis, also known as "pulseless disease," earned its nickname because one of the hallmark features of the condition is the absence or weakening of pulses in the arteries. This pulselessness typically affects the arteries of the upper body, including the arms and neck, due to inflammation and narrowing (stenosis) of these arteries. As a result, patients may present with diminished or absent pulses in the affected arteries, leading to the characteristic description of "pulseless disease." Other symptoms of Takayasu arteritis can include fatigue, fever, muscle pain, weight loss, and symptoms related to decreased blood flow to organs and tissues supplied by the affected arteries.
what HIV glycoprotein mediates HIV binding to the CD4 receptor? What HIV glycoprotein mediates HIV fusion to the cell?
The HIV glycoprotein that mediates binding to the CD4 receptor on the surface of host cells is called gp120. Gp120 forms part of the viral envelope spike, and it interacts specifically with the CD4 receptor present on the surface of CD4+ T cells, macrophages, and dendritic cells. After binding to the CD4 receptor, a conformational change occurs in gp120, which exposes a region of the glycoprotein called the co-receptor binding site. This allows another HIV glycoprotein, gp41, to interact with cellular co-receptors, primarily CCR5 or CXCR4, on the host cell membrane. Gp41 then mediates the fusion of the viral and cellular membranes, facilitating entry of the viral capsid into the host cell cytoplasm.
what amino acid is the source for GABA?
The amino acid precursor for gamma-aminobutyric acid (GABA) is glutamate. GABA is synthesized from glutamate through the action of the enzyme glutamate decarboxylase (GAD), which catalyzes the decarboxylation of glutamate to form GABA.
what is the causative agent of 5th disease? what are two other terms for 5th disease?
The causative agent of fifth disease, also known as erythema infectiosum, is a virus called Parvovirus B19. Two other terms for fifth disease are "slapped cheek syndrome" and "erythema infectiosum."
what is the drug of choice in the treatment of infections with Entamoeba histolytica, Giardia lamblia, Trichomonas?
The drug of choice for the treatment of infections with Entamoeba histolytica, Giardia lamblia, and Trichomonas vaginalis is metronidazole. Metronidazole is an antimicrobial agent that is effective against a wide range of anaerobic bacteria and protozoa, including Entamoeba histolytica (the causative agent of amoebiasis), Giardia lamblia (the causative agent of giardiasis), and Trichomonas vaginalis (the causative agent of trichomoniasis). It is important to note that while metronidazole is effective against these parasites, treatment regimens and dosages may vary depending on the severity of the infection, the individual's medical history, and other factors. Always consult a healthcare professional for proper diagnosis and treatment of parasitic infections.
what is the general mechanism of action of rifampin and what disease is it classically used to treat?
The general mechanism of action of rifampin involves inhibition of bacterial RNA synthesis by targeting bacterial RNA polymerase. Rifampin binds to the beta subunit of bacterial RNA polymerase, specifically the β-subunit, thereby preventing the initiation of RNA synthesis and ultimately leading to the inhibition of bacterial protein synthesis. Rifampin is classically used to treat tuberculosis (TB), particularly in combination with other antibiotics such as isoniazid, pyrazinamide, and ethambutol. It is also used to treat other infections caused by bacteria such as Mycobacterium leprae (the causative agent of leprosy) and certain staphylococcal and streptococcal infections.
what is the generic term for HIV (or any other virus for that matter) that uses its own reverse transcriptase to produce DNA from RNA?
The generic term for a virus, including HIV, that uses its own reverse transcriptase enzyme to produce DNA from RNA is a "retrovirus." Retroviruses are a group of RNA viruses that replicate via a unique process involving the conversion of their RNA genome into DNA, which is then integrated into the host cell genome. This reverse transcription step is facilitated by the enzyme reverse transcriptase, which synthesizes a complementary DNA strand from the viral RNA template. The resulting DNA molecule, known as a provirus, is then integrated into the host cell genome, where it can be transcribed and translated to produce new viral particles.
what type of nematode classically causes perianal pruritus, especially at night?
The nematode that classically causes perianal pruritus, especially at night, is Enterobius vermicularis, commonly known as the pinworm or threadworm. Pinworm infections are among the most common helminth infections in humans, particularly in children. The adult female pinworm migrates to the perianal area at night to lay eggs, which can cause intense itching and discomfort, often leading to scratching and further spread of the eggs. This nocturnal behavior of the pinworm contributes to the characteristic symptom of perianal itching, especially at night.
what type of staph species is most associated with UTIs?
The type of Staphylococcus species most commonly associated with urinary tract infections (UTIs) is Staphylococcus saprophyticus. Staphylococcus saprophyticus is a coagulase-negative Staphylococcus species that is frequently found in the gastrointestinal and genital tracts of healthy individuals. It is a common cause of uncomplicated UTIs, particularly in young sexually active women. Staphylococcus saprophyticus can colonize the periurethral area and ascend into the urinary tract, leading to infection. It's important to note that while Staphylococcus saprophyticus is a common cause of uncomplicated UTIs, other bacterial pathogens, such as Escherichia coli, are also frequently implicated in urinary tract infections.
what type of antibody typically crosses the placenta?
The type of antibody that typically crosses the placenta from the maternal circulation to the fetal circulation is IgG (immunoglobulin G). IgG antibodies are the most abundant type of antibody in the bloodstream and are highly effective at neutralizing pathogens and providing passive immunity to the fetus during pregnancy. During pregnancy, IgG antibodies produced by the mother can pass through the placenta via an active transport mechanism mediated by specialized receptors on the syncytiotrophoblast cells of the placenta. This transplacental transfer of IgG antibodies provides the fetus with temporary protection against various infections, helping to bolster the infant's immune defenses until its own immune system matures.
By what 2 amino acids does trypsin cleave? Does it cleave at the carboxy- or amino- side of those amino acids?
Trypsin cleaves peptide bonds specifically adjacent to the carboxyl group of the amino acids lysine (Lys) and arginine (Arg). This cleavage occurs on the carboxyl (C-terminal) side of these amino acids. Therefore, trypsin is considered an endopeptidase that cleaves peptide bonds within the interior of a polypeptide chain, specifically after lysine and arginine residues.
what is the generic term for cestodes?
flatworms, tapeworms
what is the primary flexor of the hip?
iliopsoas
what is the number one cause -- i.e. the first thing you should think of as a cause for amenorrhea?
pregnancy
what is the term for anterior displacement of one vertebra with respect to the one inferior to it?
spondylolisthesis
