Week 2 UWORLD

Klinefelter syndrome

47,XXY is the most common genotype causing Klinefelter syndrome. Patients present with tall stature; small, firm testes; azoospermia; and gynecomastia. Mild intellectual disability is seen in some patients, and the severity generally increases with each additional X chromosome

What is an example of a drug that inhibits primary active transport? (gastric)

Omeprazole- Parietal cells release hydrogen ions into the gastric lumen by means of the H/K ATPase, which requires hydrolysis of ATP and is therefore an active transport mechanism. Omeprazole and other proton pump inhibitors suppress the activity of the gastric parietal cell H/K ATPase leading to an increase in the pH of the gastric lumen.

How do you perform stem cell transplantation in a patient with congenital genomic disease?

Patients who require stem cell transplantation due to a congenital genomic disease typically receive *matched unrelated donor cells* because they will have matched human leukocyte antigen alleles but will not have the genomic mutation that caused the condition. You don't want to give them autologous(harvested stem cells), syngentic(cells from identical twin), an because the stem cells would still have the genetic mutation. Synge

Primary Nocturnal Enuresis

Primary nocturnal enuresis (ie, bed-wetting at age ≥5 without prior nighttime urinary continence) is caused primarily by a brain maturational delay in the development of bladder control

Thiamine Deficiency (B1)

Thiamine deficiency impairs glucose utilization in the CNS. This happens due to decreased activity of the enzymes that use thiamine as a cofactor(pyruvate dehydrogenase, a ketoglutarate dehydrogenase, transketolase) -Dx: Low baseline erythrocyte transketolase activity but increases after addition of thiamine pyrophophate.

Vitamin B2 (Riboflavin)

cheilosis, stomatitis, glossitis, anemia, and seborrheic dermatitis

Carpal tunnel syndrome

compression of the *median nerve* as it passes between the ligament and the bones and tendons of the wrist

What are the probabilities that a given sibling will share some or all of the same HLA genes?

-1/4 chance of inheriting all the same HLA genes(identical HLA match) -1/2 chance of inheriting half of the same HLA genes(haploidentical HLA match) 1/4 chance of inheriting none of the same HLA genes(1/4)

When treating hypovolemic shock, the most important intervention is infusing intravenous fluids? What does this do physiologically?

. By infusing intravenous fluids, intravascular volume and ventricular preload can be increased rapidly. The increase in preload stretches the myocardium and increases the end-diastolic sarcomere length, leading to an increase in stroke volume and cardiac output by the Frank-Starling mechanism. Intravenous fluids increase the intravascular and left ventricular end-diastolic volumes. The increase in preload stretches the myocardium and increases the end-diastolic sarcomere length, leading to an increase in stroke volume and cardiac output by the Frank-Starling mechanism

Technique of the blot tests

All of the "blot" tests rely on the same basic techniques. First, the components of the unknown sample - *DNA for Southern blots, mRNA for Northern blots, protein for Western blots, and DNA-bound protein for Southwestern blots* - are separated by size and charge via gel electrophoresis. The resultant bands are then blotted onto a nitrocellulose membrane and incubated with a labeled hybridization probe or antibody to identify the specific DNA fragment, mRNA molecule or protein of interest.

Which of the following is the best method to determine if a gene is being transcribed in cultures of the isolated cells?

As *transcription* refers to the production of mRNA from a DNA template, a test that detects specific mRNA sequences (Northern blot) would be most appropriate.

Cerebral AV malformations

Cerebral arteriovenous malformations (AVMs) are vascular malformations histologically characterized by a tangle of abnormal vessels, including large veins with thickened walls and irregular arteries. AVMs may present with intracranial hemorrhage, headache, and/or seizures. Radiologic findings include abnormal vasculature with a "bag of worms" appearance and multiple dark flow voids

Pyridoxine (B6) deficiency

Cheilosis, stomatitis, glossitis, dermatitis

Down Syndrome (Trisomy 21)

Common findings in Down syndrome include cognitive impairment, facial dysmorphism, and cardiac defects; 95% of cases are caused by the presence of an extra chromosome 21 (trisomy) resulting from nondisjunction. Unbalanced Robertsonian translocations or mosaicism are less common causes.

Whats the connection between indirect inguinal hernias and noncommunating hydroceles?

Communicating hydroceles and indirect inguinal hernias are caused by an incomplete obliteration of the processus vaginalis. The resultant connection between the scrotum and abdominal cavity can allow for fluid leakage (hydrocele) or the passage of abdominal contents (indirect inguinal hernia).

Southern blot

DNA

Southwestern blot

DNA-binding proteins

Turner Syndrome

In females, loss of an X chromosome (45,XO karyotype) results in Turner syndrome, which presents with short stature, broad chest, and primary amenorrhea.

Haldane effect

In the lungs, the binding of O2 to hemoglobin drives the release of H+ and CO2 from hemoglobin (Haldane effect)

Lesions of Oculomotor Nerve

Lesions involving the oculomotor nerve (CN III) cause ptosis, a downward and laterally deviated eye, impaired pupillary constriction and accommodation, and diagonal diplopia. The most dreaded cause of CN III palsy is an enlarging intracranial aneurysm.

Lesions of the oculomotor nerve

Lesions involving the oculomotor nerve (CN III) cause ptosis, a downward and laterally deviated eye, impaired pupillary constriction and accommodation, and diagonal diplopia. The most dreaded cause of CN III palsy is an enlarging intracranial aneurysm.

Fragile X Syndrome

Macroorchidism, large jaw, and intellectual disability are seen in patients with fragile X syndrome, an X-linked disorder caused by mutations in the fragile X mental retardation 1 gene.

Reperfusion injury

Reperfusion injury is thought to occur secondary to oxygen free radical generation, mitochondrial damage, and inflammation.

Thiamine Deficiency (B1)/ Beriberi

Thiamine deficiency causes beriberi and Wernicke-Korsakoff syndrome. Dry beriberi is characterized by symmetrical peripheral neuropathy; wet beriberi includes the addition of high-output congestive heart failure.

Ascorbic Acid (Vitamin C) deficiency

Scurvy( petechial hemorrhages , gingival swelling , impaired wound healing, weakened immune response)

What is an example of a drug that inhibits primary active transport? (pufferfish)

Tetrodotoxin, =functions by blocking the voltage gated sodium channels in nerve cells. it inhibits the passive transport of SODIUM

Which of the following areas of the nephron is normally impermeable to water regardless of serum vasopressin levels?

The ascending limb of the loop of Henle is impermeable to water regardless of serum vasopressin levels. Reabsorption of electrolytes by the Na+/K+/2Cl- cotransporter occurs in the thick ascending limb and contributes to formation of the corticomedullary concentration gradient

What happens during O2 loading and unloading ?

The binding of O2 to hemoglobin increases the affinity for binding of subsequent O2 molecules (cooperative binding). In the lungs, the binding of O2 to hemoglobin drives the release of H+ and CO2 from hemoglobin (Haldane effect). In the peripheral tissues, high concentrations of CO2 and H+ facilitate O2 unloading from hemoglobin (Bohr effect)

Which muscles are involved in the down and out position ?

The eye rests in a "down and out" position due to the unopposed action of the superior oblique (CN IV) and lateral rectus (CN VI) muscles.

Ulnar nephropathy

The ulnar nerve can be injured at the medial epicondyle of the humerus ("funny bone") or in Guyon's canal near the hook of the hamate and pisiform bone in the wrist. Patients often have sensory loss over the medial 1½ digits and hypothenar eminence, and weakness on wrist flexion/adduction, finger abduction/adduction, and flexion of the fourth/fifth digits. The hypothenar eminence may flatten due to muscle atrophy.

Catecholamine synthesis

Tyrosine --> L-Dopa --> Dopamine --> Norepinephrine --> Epinephrine

What is an example of a drug that inhibits passive transport of calcium ions in cardiomyocytes?

Verapamil

Panic attack physiology

When a person experiences a panic attack, there is decreased PaCO2 which causes decreased cerebral perfusion-->CNS symptoms(

Northern Blot

mRNA

Cobalmin (B12) deficiency

macrocutic anemia. upper & LMN dysfunction and sensory peripheral neuropathy

Vitamin A(retinol) deficiency

night blindness, xerophthalamia, and vulnerability to infection(measles)

Niacin deficiency

pellagra: dermatitis, diarrhea, dementia, death

Western blot

protein

Potter sequence

results from a urinary tract anomaly (eg, bilateral renal agenesis) that causes decreased fetal urine output and severe oligohydramnios. The lack of amniotic fluid causes increased fetal compression (eg, flat facies, limb deformity) and pulmonary hypoplasia (eg, neonatal hypoxia), which is the most common cause of death in affected neonates.