Uworld11

Question 1

vasopressin-2 receptor mutations are a cause of?

Answer 1

congenital nephrogenic diabetes insipidus, a condition in which renal resistance to antidiuretic hormone results in excessive urinary water losses.

findings: high baseline serum osmolality (typically with hypernatremia), persistently dilute urine after water deprivation (low urine osmolality) and lack of response to desmopressin.

Question 2

Autism spectrum disorder is characterized by?

Answer 2

impaired social communication/interactions and restricted, repetitive interests or behaviors.

It can occur with or without language and intellectual impairment.

Question 3

Defective anterior (rostral) neuropore closure (eg, anencephaly) results in?

Answer 3

failure of the skull and meninges to form, allowing exposure of the developing brain to the destructive effects of amniotic fluid.

Open neural tube defects are a result of defects in primary neuralation (development and closure of the neural tube).

Question 4

Aside from cigarette smoke, what is the most important environmental risk factor for lung cancer?

Answer 4

Radon is a radioactive gas found throughout the earth that enters homes through contaminated soil and groundwater. It emits highly ionzing alpha radiation, causing DNA damage in the respiratory tract epithelium when inhaled.

Question 5

Folate deficiency inhibits?

Answer 5

the synthesis of nucleic acids, particularly the formation of thymidine.

This leads to defective DNA synthesis and increased apoptosis affecting hemopoietic cells (megaloblastic anemia).

Thymidine supplementation bypasses the enzyme thmidylate synthase and can reduce erythroid cell apoptosis.

Question 6

How can glycerol be be used to synthesize glucose during gluconeogenesis?

Answer 6

Glycerol produced by the degradation of triglycerides in adipose tissue can be used by glycerol kinase in the liver and kidney to synthesize glucose during gluconeogensis.

Question 7

What is cholesteatomas?

Answer 7

collections of squamous cell debris that form a mass behind the tympanic membrane.

Can be congenital or may occur as an acquired primary lesion or following infecton, trauma, or surgery of the middle ear.

Can cause hearing loss due to erosion into auditory ossicles.

Question 8

The histopathologic features of esophageal squamous cell carcinoma include?

Answer 8

solid nests of neoplastic squamous cells with abundant eosinophilic cytoplasm and distinct borders.

Areas of keratinization and the presence of intercellular bridges are also present.

Patients present with progressive solid and eventually liquid dysphasia and weight loss.

Question 9

What is sick sinus syndrome>

Answer 9

Sick sinus syndrome results from degeneration (usually age related) of the sinoatrial node, leading to impaired conduction and reduced cardiac output with symptoms of dyspnea, fatigue, lightheadedness, presyncope, and syncope.

ECG: bradycardia with sinus pauses (delated P waves), sinus arrest (dropped P waves) and junctional escape beats

Question 10

Calcium efflux from cardiac cells prior to relaxation is primarily mediated via?

Answer 10

Na/Ca exchange pump and sarcoplasmic reticulum Ca-ATPase pump

Question 11

What is the most common cause of renal infarction?

Answer 11

Systemic thromboembolism, often due to thrombus formation during atrial fibrillation.

Renal infarction presents with flank pain, hematuria, elevated lactate dehydrogenase, and a wedge shaped kidney lesion on CT.

The brain and kidneys are more likely to suffer embolic infarctions because they are perfused at a higher rate.

Question 12

The initial management of septic shock requires rapid fluid resuscitation to replace intravascular volume and restore adequate end-organ perfusion. This is best accomplished with?

Answer 12

intravenous boluses of isotonic crystalloid in the form of 0.9% (normal) saline or lactated Ringer solution because these solutions remain in the extracellular space.

Question 13

What is Kartagener syndrome?

Answer 13

a form of primary ciliary dyskinesia characterized by the triad of situs inversus, chronic sinusitis, and bronchiectasis.

Occurs due to mutations that impair the structure or function of cilia

Question 14

Scaphoid fracture increase the risk of?

Answer 14

Scaphoid fracture can disrupt retrograde blood supply to the proximal scaphoid, increasing risk of avascular necrosis.

Fracture of the scaphoid bone may result from a fall on an outstretched hand and should be suspected if exam shows tenderness in the anatomic snuff box.

Question 15

Patients with Bell Palsy may experience?

Answer 15

Because of the diverse functions of the facial nerve CNVII, patients with Bell palsy may experience decreased tear production, hyperacusis, and/or loss of taste over the anterior 2/3 tongue, in addition to unilateral facial weakness.

Question 16

How does phenytoin cause vitamin D def?

Answer 16

Phenytoin and other antiepileptic meds are inducers of cytochrome P450 enzymes, including CYP24, which converts 25-hydroxyvitamin D to 24,25-dihydroxyvitamin D (inactive from).

As a result, there is less 25-hydroxyvitamin D available for conversion to 1,25-dihydroxyvitamin D (Active form), leading to def

Question 17

Parathyroid hormone is released in a combination continuous/tonic and pulsatile pattern. Continous high levels of PTH lead to?

Answer 17

excessive release of calcium from bones and increase risk of osteoporosis.

Question 18

Parathyroid hormone is released in a combination continuous/tonic and pulsatile pattern. Pulsatile secretion leads to?

Answer 18

an anabolic effect on bone metabolism, stimulating osteoblast proliferation and inducing increased formation of new bone.

Question 19

Atrial natriuretic peptide, brain natriuretic peptide, and nitric oxide activates?

Answer 19

guanylyl cyclase and increase conversion of guanosine 5’-triphosphate to cyclic guanosine 3’,5’-monophosphate (cGMP).

Question 20

MOA of phosphodiesterase inhibitors (eg, sildenafil)

Answer 20

decrease the degradation of cGMP.

Elevated intracellular cGMP levels lead to relaxation of vascular smooth muscle and vasodilation.

Question 21

What is pleiotropy?

Answer 21

pleiotropy describes instances where multiple phenotypic manifestations result from a single genetic mutation

Question 22

Rheumatoid arthritis has what antibodies?

Answer 22

Rheumatoid arthritis: symmetric polyarthritis (involving the metacarpophalangeal and proximal interphalangeal joints) with prolonged morning stiffness and fatigue.

Antibodies to citrullinated peptides/proteins have a high specificity for the condition.

Question 23

What is polycythemia vera?

Answer 23

a myeloproliferative disorder characterized by uncontrolled erythrocyte production.

Almost all patients have a mutation in the JAK2 gene, which encodes a non-receptor (cytoplasmic) tyrosine kinase a/w the erythropoietin receptor.

Question 24

What makes the pulmonary vascular bed unique?

Answer 24

The pulmonary vascular bed is unique in that tissue hypoxia results in a vasoconstrictive response.

Such hypoxic vasoconstriction occurs in the small muscular pulmonary arteries to divert blood flow away from underventilated lung regions and toward well-ventilated lung areas to minimize ventilation-perfusion mismatch, leading to more efficient overall gas exchange.

Question 25

Pathogenesis of chronic granulomatous disease

Answer 25

Defective intracellular killing of phagocytized organisms within neutrophils due to an impaired respiratory burst. CGD should be suspected in a child with recurrent infections by catalase+ organisms (staph aureus, aspergillus) who has normal immunoglobins and no leukopenia.

Question 26

Why can repeat infection of dengue be more severe?

Answer 26

There are 4 different serotypes of dengue virus. Repeat infection occurs when a person is exposed to a serotype not previously encountered. Secondary infections are often far more severe than primary infections and may be a/w a life threatening shock syndrome.

Question 27

MOA of class IA antiarrythmics (quinidine, procainamide, disopyramide)

Answer 27

sodium channel blocking agents that depress phase 0 depolarization. They also prolong repolarization due to moderate potassium channel blocking activity, increasing action potential duration in cardiac myocytes

Question 28

What is hereditary hemochromatosis?

Answer 28

AR disease characterized by excessive gastrointestinal absorption of iron, which is then stored as hemosiderin in various tissues. Secondary arthritis is common and typically involves the second and third metacarpophalangeal joints. Liver disease, skin hyperpigmentation, diabetes, pituitary hormone def (eg central hypogonadism) and cardiomyopathy can also manifest.

Question 29

What is croup

Answer 29

croup is a viral infection in which edema and narrowing of the proximal trachea (subglottis) result in a barky cough and inspiratory stridor.

Question 30

MOA of penicillins

Answer 30

penicillins, structurally similar to D-alanine-D-alanine, inhibit transpeptidase by binding covalently to its active site. The result is failed synthesis of the bacterial peptidoglycan cell wall

Question 31

What does the murmur of aortic stenosis sound like?

Answer 31

systolic ejection type, crescendo-decrescendo murmur that starts after the first heart sound and typically ends before the A2 component of the second heart sound. The intensity of the murmur is proportional to the magnitude of the left ventricle to aorta pressure gradient during systole.

Question 32

what is the formula of maintenance dose?

Answer 32

clearance (CL) determines the dose rate required to maintain a given steady-state plasma concentration (Css) maintenance dose= Css x CL x dosing interval

Question 33

What does helicobacter pylori produce?

Answer 33

Produces the enzyme urease, which spilts urea into CO2 and ammonia and neutralizes the local acidic gastric pH. Active infection can be confirmed through rapid urease testing, in which a biopsy specimen of gastric mucosa is evaluated in the presence of urea and a pH indicator. Evidence of alkalization (due to ammonia formation) confirms the diagnosis

Question 34

What are some complications of hand foot and mouth disease?

Answer 34

hand foot and mouth disease (oral ulcerations and rash on palms/soles) is a common manifestation of enterovirus infection. Although enterovirus are typically self-limited, rare but serious complications include myocarditis and aseptic meningitis.

Question 35

Closure of a patent ductus arteriosus results in?

Answer 35

decreased pulmonary venous return to the left atrium (decreased left ventricular preload) and increased diastolic blood pressure in the aorta (increased left ventricular afterload). Together, these changes acutely lower left ventricular stroke volume and cardiac output

Question 36

What is the virulence factor for group B strep

Answer 36

GBS is a major cause of neonatal sepsis. Virulence factor: polysaccharide capsule, which contains sialic acid residues that prevent phagocytosis via molecular mimicry

Question 37

What is a complication of giant cell arteritis?

Answer 37

GCA: granulomatous inflammation of the media with fragmentation of the internal elastic lamina most often affecting the medium and small branches of the carotid artery Ischemic optic neuropathy with irreversible blindness is a potential complication; therefore patients require immediate glucocorticoid therapy

Question 38

function of osteocytes

Answer 38

Osteocytes detect increased mechanical load in the bones (eg, weight-bearing exercise) and communicate with one another through gap junctions to orchestrate bone remodeling.

Question 39

What is adenovirus

Answer 39

self-limiting, year round infection that causes the acute onset of fever, cough, congestion, pharyngitis, and conjunctivitis. This pharyngoconjunctival disease can occur in outbreaks among those living in close quarters (eg, camp dormitories, military barracks).

Question 40

Side effects of ketamine

Answer 40

Ketamine can be used for anesthesia induction. The side effects of increased catcecholamine release (eg, bronchodilation) are often exploited in patients with bronchospasm

Question 41

What is the difference between live attenuated oral (Sabin) poliovirus vaccine and inactivated poliovirus (Salk) vaccine?

Answer 41

The live attenuated oral (Sabin) poliovirus vaccine produces a stronger mucosal secretory IgA immune response than does the inactivated poliovirus (Salk) vaccine. This increase in mucosal IgA offers immune protection at the site of viral entry by inhibiting attachment to intestinal epithelial cells.

Question 42

Function of incretin?

Answer 42

Incretin functions by stimulating insulin release following oral consumption of glucose. Incretin-stimulated insulin release is independent of the increase in insulin secretion brought on by elevations in the blood glucose level

Question 43

Function of erythropoietin (EPO)?

Answer 43

EPO is produced by peritubular fibroblast cells in the renal cortex in response to decreased renal oxygen delivery. EOP acts on erythrocyte precursors in the bone marrow to increase red blood cell production. Patients with chronic kidney disease often have damage to renal EPO-producing cells, which results in normocytic anemia.

Question 44

Patients with preeclampsia are at risk for?

Answer 44

fetal growth restriction and oligohydramnios due to abnormal placental spiral artery development, which leads to increased placental vascular resistance, decreased uteroplacental perfusion, and decreased umbilical vein oxygen delivery

Question 45

What is low grade atrioventricular block (ie, first degree, Mobitz type 1 second degree)?

Answer 45

low grade atrioventricular block (ie, first degree, Mobitz type 1 second degree) involves conduction disruption within the AV node. The occurence of low grade AV block in the setting of myocardial infarction suggests obstruction of the right coronary artery because it supplies blood to the AV node in approximately 90% of patients.

Question 46

What is glioblastoma?

Answer 46

Most common primary cerebral tumor of adults Typically located within the cerebral hemispheres, occasionally crossing the midline (butterfly glioma).

Question 47

Gross exam of glioblastoma

Answer 47

highly malignant tumor often shows a poorly circumscribed, variegated mass containing areas of necrosis and hemorrhage

Question 48

What is relaxin?

Answer 48

during pregnancy, increased relaxin levels promote sacroiliac joint laxity and widening of the pubic symphysis to help facilitate vaginal delivery

Question 49

What is a brain abscess?

Answer 49

A brain abscess appears as a ring enhancing lesion on imaging and typically causes headache with or without fever and neurologic symptoms (eg, seizure). Pathogenesis often involves direct spread from head and neck space infections, such as acute otitis media.

Question 50

Chronic kidney disease causes what to phosphate and vitamin D levels?

Answer 50

Chronic kidney disease usually causes hyperphosphatemia (binds serum Ca2+) and low 1,25-dihydroxy vitamin D (decreases intestinal Ca2+ absorption and Ca2+ release from bone). The resulting hypocalcemia stimulates release of parathyroid hormone, causing secondary hyperparathyroidism

Question 51

What is stasis dermatitis?

Answer 51

Chronic erythema, fibrosis, and reddish brown discoloration due to deposition of hemosiderin (from breakdown of extravasated red cells). Symptoms are typically bilateral, and usually worse at or above the ankles. Complications: poor wound healing, weeping, ulceration

Question 52

What is the function of glucose-6-phosphate dehydrogenase?

Answer 52

Catalyzes the conversion of glucose-6-phosphate to 6-phosphogluconolactone. It is the rate limiting enzyme of the pentose phosphate pathway.

Question 53

What is glucose-6-phosphate deficiency?

Answer 53

a common X-linked recessive disorder resulting in episodes of hemolytic anemia during times of increased oxidative stress (eg, use of antimalarials/sulfonamide, infections)

Question 54

Eccrine sweat glands and the adrenal medullae are innervated by?

Answer 54

cholinergic neurons

Question 55

the sympathetic nervous system typically regulates visceral fuction via?

Answer 55

2-neuron signal transmission involving cholinergic preganglionic neurons and adrenergic postganglionic neurons

Question 56

MOA of fibrates (gemfibrozil, fenofibrate)

Answer 56

Fibrates lower triglyceride levels by activating peroxisome proliferator-activated receptor alpha, which leads to decreased hepatic VLDL production and increased lipoprotein lipase activity. Fish oil supplements containing high concentrations of omega-3-fatty acids lower triglycerides by decreasing production of VLDL and apolipoprotein B.

Question 57

Location of the third part of the duodenum

Answer 57

The third part of the duodenum courses horizontally across the abdominal aorta and inferior vena cava at the level of the third lumbar vertebra. The superior mesenteric vessels lie anterior to the duodenum at this location.

Question 58

At high altitude, the low partial pressure of inspired oxygen (PiO2) leads to?

Answer 58

At high altitude, the low partial pressure of inspired oxygen (PiO2) leads to hypoxemia that triggers hyperventilation with increased exhalation of CO2 and resulting respiratory alkalosis. The kidneys compensate by increasing bicarbonate (HCO3-) excretion to decrease serum HCO3- and help normalize pH. Hypoxemia persists, but physiologic adjustments take place to improve O2 use.

Question 59

What is helpful for delirium prevention and management?

Answer 59

Because disruption of the sleep-wake cycle is both a risk factor and manifestation of delirium, facilitation of nocturnal sleep (eg, minimizing noise and patient interventions, appropriate day/night lighting) is helpful for delirium prevention and management.

Question 60

What is ecthyma gangrenosum?

Answer 60

A cutaneous necrotic disease with a strong associated with Pseudomonas aeruginosa bacteremia. It occurs from perivascular invasion and release of tissue-destructive exotoxins, causing vascular destruction and insufficient blood flow to patches of skin that become edematous and subsequently necrose.

Question 61

Pseudomonas infections are common in which patients?

Answer 61

neutropenic, are hospitalized, have burns, or have indwelling catheters.

Question 62

Integral membrane proteins contain?

Answer 62

transmembrane domains composed of alpha helices with hydrophobic amino acid residues (eg, alanine, valine, leucine, isoleucine, phenylalanine, tryptophan, methionine, proline, glycine.) These transmembrane domains help anchor the protein to the phospholipid bilayer of the cell membrane.

Question 63

Abortive therapy for migraines

Answer 63

Migraine is an episodic disorder characterized by severe, often unilateral headache commonly associated with nausea and sensitivity to light and sound. Abortive therapy: mild analgesics, triptans, antiemetics, ergotamine) for acute symptoms

Question 64

What is preventative therapy for migraines?

Answer 64

beta blockers, tricyclic antidepressants, anticonvulsants, CGRP monoclonal antibodies) to reduce the frequency of headaches

Question 65

Where is the somatosensory cortex located?

Answer 65

just posterior to the central sulcus

Question 66

A lesion in the somatosensory cortex leads to?

Answer 66

A lesion in the somatosensory cortex, located just posterior to the central sulcus, leads to contralateral sensory deficits and cortical sensory signs.

Question 67

What is an empyema?

Answer 67

An accumulation of pus within the pleural space that can result from multiple sources of bacterial contamination. It usually represents advanced progression of a complicated parapneumonic effusion resulting from bacterial translocation from the alveoli

Question 68

What is holoprosencephaly?

Answer 68

Due to failure of the primitive forebrain (prosencephalon) to divide into the right and left hemispheres, resulting in a spectrum of brain and midface abnormalities (eg, facial clefts, cyclopia) Trisomy 13 (Patau) is the most commonly associated etiology

Question 69

Cystic fibrosis is most commonly due to?

Answer 69

Due to a 3-base pair deletion in the CF transmembrane conductance regulator gene at amino acid position 508. This mutation impairs post translational processing of CFTR, resulting in shunting of CFTR toward the proteasome, with complete absence of the protein on the cell surface. Elevated sweat chloride concentrations are found in most patients with CF.

Question 70

Primary tuberculosis causes?

Answer 70

the formation of Ghon foci in the lower lungs.

Question 71

Secondary (reactivation) tuberculosis occurs in?

Answer 71

patients with prior tuberculosis infection that never cleared completely. reactivation TB occurs most often in immunosuppressed patients and is characterized by apical cavitary lesions and hemoptysis.

Question 72

MOA of proton pump inhibitors (omeprazole, lansoprazole)

Answer 72

block the final common pathway of gastric acid secretion from parietal cells, in which is stimulated by acetylcholine, histamine, and gastrin

Question 73

Whitish/gray areas in melanoma

Answer 73

whitish/gray areas occur when cytotoxic T cells recognize tumor antigens and destroy malignant cells, leading to melanocyte regression.

Question 74

Red areas of melanoma

Answer 74

Red areas arise due to vessel actasia and local inflammation

Question 75

brown or black areas in melanoma

Answer 75

due to advancing malignant melanocytes

Question 76

What is seen in salicylate intoxication?

Answer 76

Salicylate intoxication should be suspected in patients with the triad of fever, tinnitus, and tachypnea. Salicylates both stimulate central respiratory drive to cause primary respiratory alkalosis and disrupt cellular metabolism to cause primary anion gap metabolic acidosis. Therefore, toxicity classically presents with a mixed acid-base disturbance and a blood pH sometimes within the normal range.

Question 77

What is used for the txt of essential tremor?

Answer 77

Beta blockers. Propranolol, a nonselective beta blocker, is the most commonly used therapy and prevents the interaction of epinephrine and norepinephrine with beta 1 and beta 2 receptors to relieve tremor symptoms. However, inhibition of pulomnary beta 2 receptors in patients with underlying reactive airway disease can cause bronchoconstriction, leading to cough, wheeze, and dyspnea.

Question 78

The most common form of congenital adrenal hyperplasia?

Answer 78

21-hydroxylase deficiency. genetically female infants typically have ambiguous genitalia (virilzation) at birth, whereas males have phenotypically normal genitalia, with salt-wasting or precocious puberty appearing later. Elevated 17-hydroxyprogesterone is diagnostic.

Question 79

What are compensatory mechanisms for hypovolemia?

Answer 79

Activation of renin-angiotensin-aldosterone system and increased antidiuretic hormone release This results in increased renal sodium, chloride, water, and urea reaborption with increased potassium excretion.

Question 80

Role of nucleolus?

Answer 80

The nucleolus is the site of ribosomal RNA (rRNA) transcription and ribosomal subunit assembly. RNA polymerase I functions exclusively within the nucleolus to transcribe the 45S pre-rRNA gene, which codes for most of the rRNA components (18S, 5.8S, and 28S rRNAs)

Question 81

What is Toxoplasma gondii?

Answer 81

an intracellular parasite that typically transmitted to humans after accidental ingestation of contaminated cat feces (eg, cat handling, litter box). Most initial cases are asymptomatic. However, the organism establishes a latent infection that can reactivate in the setting of severe immunocompromise, particularly advanced AIDS. Patients usually develop encephalitis with multiple ring-enhancing lesions.

Question 82

Deficiency in folate causes?

Answer 82

Folate is essential for nucleic acid metabolism, and def causes ineffective hematopoiesis with a low reticulocyte count. Characteristic megaloblastic changes include hypersegmented neutrophils and macrocytic red blood cells. Macrocytic erythrocytes are prone to hemolysis, which can increase serum bilirubin and lactate dehydrogenase.

Question 83

Cerebellar hemisphere lesions result in?

Answer 83

Cerebellar hemisphere are responsible for motor planning and coordination of the ipsilateral extremities via their connections with the lateral descending motor systems. Consequently, cerebellar hemisphere lesions typically result in ipsilateral dysdiadochokinesia, limb dysmetria, and/or intention tremor.

Question 84

Immunoflorescence and EM of poststrep glomerulonephritis?

Answer 84

lumpy bumpy granular deposits of IgG and C3 on the glomerular basement membrane, and subepithelial, electron dense deposits are seen on EM.

Question 85

What is poststrep glomerulonephritis?

Answer 85

an immune complex deposition disease that occurs 2-4 weeks after exposure to group A beta hemolytic Strep species (pharyngitis, skin infection) Light microscopy shows enlarged, hypercellular glomeruli

Question 86

What is transformation?

Answer 86

allows bacterium to take up exogenous DNA fragments and express the encoded proteins. Strep pneumo can undergo transformation. Through this method, strains of S pneumo that do not form a capsule can acquire the genes that code for the capsule and therefore gain virulence.

Question 87

Interferon-gamma release assays test for latent tuberculosis infection by?

Answer 87

measuring the amount of IFN-gamma released by T lymphocytes when exposed to antigens unique to Mycobacterium tuberculosis.

Question 88

Meckel diverticulum results from?

Answer 88

incomplete obliteration of the vitelline duct and usually presents with painless lower GI bleeding. 99m-Tc-pertechnetate localizes to heterotopic gastric mucosa that is often contained within a Meckel diverticulum, and uptake in the periumbilical area or right lower quadrant is diagnostic.

Question 89

Function of poly-A tail

Answer 89

The poly-A tail is not transcribed from DNA; instead, it is added as a post-transcriptional modification downstream of the consensus sequence (AAUAAA) located near the 3' end of the mRNA molecule. This tail protects mRNA from degradation within the cytoplasm after it exits the nucleus

Question 90

What is De Quervain tendinopathy?

Answer 90

Characterized by tendinous myxoid degeneration and thickening of tendon sheaths involving the abductor pollicis longus and extensor pollicis brevis in the first extensor compartment. It presents with sharp pain in the lateral hand and wrist, with reproduction of symptoms by passive thumb flexion with the hand in ulnar deviation

Question 91

Impaired beta-oxidation of fatty acids causes?

Answer 91

hypoglycemia after prolonged fasting and insufficient levels of ketone bodies.

Question 92

What enzymes is most commonly deficient in impaired beta-oxidation?

Answer 92

Acyl-CoA dehydrogenase catalyzes the first step in the beta-oxidation pathway and is the most commonly deficient enzyme

Question 93

What recognizes stop codons?

Answer 93

Releasing factors recognize stop codons (UAA, UAG, UGA) and terminate protein synthesis. They facilitate the release of the polypeptide chain from the ribosome and dissolution of the ribosome-messenger RNA complex

Question 94

The glomerular filtration rate (GFR) can be estimated by?

Answer 94

the inulin or creatinine clearance

Question 95

Renal plasma flow (RPF) is calculated using?

Answer 95

the para-aminohippuric acid clearance.

Question 96

What is filtration fraction?

Answer 96

FF= GFR/RPF The fraction of the RPF that is filtered across the glomerular capillaries into Bowman's space. It is usually equal to 20% in healthy individuals.

Question 97

How can staph aureus cause necrotizing pneumonia?

Answer 97

staph aureus strains that express Panton-Valentine leukocidin (PVL), a protease that kills leukocytes and causes necrosis, are most likely to cause skin or soft-tissue abscess and invasive disease (eg necrotizing pneumonia) PVL expression is most common in community-acquired, methicillin-resistant strains.

Question 98

The most common cancers in women in order of incidence?

Answer 98

2019 estimates, the most common cancers (exclusing basal and squamous cell skin cancer) in women by order of incidence are breast, lung, and colorectal. In terms of mortality, lung cancer claims the most lives, followed by breast and colorectal cancer.

Question 99

What is retinitis pigmentosa?

Answer 99

a genetic condition resulting in progressive dystophy of retinal pigmented epithelium and photoreceptors. Patients typically present with progressive night blindness and loss of peripheral vision due to early loss of rods, which are highly metabolically active. Funduscopic exam: show dark pigments deposited in a bone-spicule pattern in addition to retinal vessel attenuation and optic disc pallor.