Block 36 Flashcards
Saccular stage of lung development,
Premature birth
- in the terminal saccular stage of lung development, the type II pneumocytes produces pulmonary surfactant, a lipoprotein complex rich in phospholipids, most notably DPPC.
- this surfactant decreases alveolar surface tension by creating lipid rich monolater that seperate alveolar gas from the underlying aqueous fluid.
- efflux of lung into amniotic fluid enables testing of markers lung maturity, untill 33 week of gestation, the L and S values are about equal, after 33 weeks the L levels rises dramaticly compared to S.
- L/S ratio of 1.9 is indicative of mature fetal lungs.
Alzehaimer disease biochemical abnormality
The most important biochemical abnormality seen in alzehaimer disease is decrease in Ach levels. This occurs due to deficiency of choline actyltransferase.
- the decline in actyltransferase is most notable in the basal nucleus of meynert which precipitates in momory and cognition.
- the nucleus is located at the base of forebrain and widely projects to the neocortex.
- another involved structure is the hippocampus, the major function of it is formation of new memories.
Medication that selectively binds to IL-1 inducible enzyme that is highly expressed by inflammatory cells and undetectible in surrounding normal tissue
COX-2 inhibitor - celecocxib in gout.
-COX-2 is an inducible enzyme that is undetected in most tissues normally. during inflammation, infiltrating cells secrete cytokines (IL-1, TNF-å) that causes COX-2 upregulation in the inflamed tissue.
Polycythemia vera mutation
PV is caused by abnormal transduction of EPO growth signals.
The erythropoietin receptor has no intrinsic kinase activity and must interact with JAK2, a cytoplasmic (non-receptor) tyrosine kinase, to initiate downstream signaling. All pts with PV have mutation in JAK2 that causes constitutive activation of its kinase domain, resulting in clonal proliferation of myeloid cells. JAK2 mutation have also been implicated in essential thrombocythemia, primary myelofibrosis and other myelproliferative disorders.
Recombination
Refers to the exchange of genes between 2 chromosomes via crossing over within homologous regions. The resulting progeny can have recombined genomes with traits fro both parent viruses. This usually occur in nonsegmented viruses such as herpes virus (unlike reasorment which occurs in segmented virus such as infleuenza)
Phenotypic mixing
Occurs when a host cell is coinfected with 2 viral strains and progeny virions contains parental genome from one strain and nucleocapsid (or envelope) proteins from the other strain.
-this may result in a progeny acquiring additional traits (eg, enhanced ability to infect new host cells due to different nucleocapsid proteins).
Brunner glands
Secrete copious amounts of alkaline mucus into the dudenoum, they are found within the first part of duodenum. These glands are most numerous at pylorus but may be found intermittently up to the ampulla of vater.
-the ducts of these glands pass through the muscularis mucosa and terminates in the mucosal crypts.
Which side effect would persist even after adding carbidopa to levodopa treatment
Anxiety and agitation.
- anxiety is increased because more dopamine is available to the brain. Adding carbiodopa inhibits the peripheral conversion levodopa, making more of it available to the brain.
- high dose combination levodopa/carbidopa, can cause various behavioral changes such as anexiety, agitation, insmonia, confusion, delusions and hallucinations. Reducing the dose is helpful in alleviating these adverse effects. If reduced dosage is not possible, atypical antipsychotics, such as clozapine, may be helpful.
Drug that act on enahancing postsynaptic chloride influx in status epliepticus.
benzodiazepines enhances the effect of the inhibitory neurotransmitter GABA-A, a ligand gated ion channel. Allosteric attachment of benzodiazepines to the GABA-A receptor causes increased influx of negatively charged chloride ions in response to GABA binding.
-this leads to hyperpolarization of postsynaptic neuron and suppression of action poteintial firing.
Pathogenesis of congestive heart failure
Heart failure occurs when a structual or functional cardiac disorder impairs ventricular filling or ejection of blood causing reduced CO and excessive ventricular filling pressures.
- the reduced CO is detected as an initial drop in BP which triggers compensatory neurohumoral stimulation directed at maintaining BP and tissue perfusion.
- this compensatory response is mediated cheifly through increased in “symphathetic nervous system activity, stimulation of RAAS and release of ADH.
- however these adaptation often lead to severe consequences such as -increased afterload from excessive vasoconstriction can further impede cardiac output and lead to excess fluid retention due to poor renal perfusion.
- high-renin angiotensis activity also increases fluid retention, which contributes to peripheral edema and pulmonary congestion. Heart failoure symptoms of circulatory overload is often called congestive HF.
- deleterious cardiac remodelling occurs secondary to hemondynamic stress and neurohumoral stimulation thereby prepetuating a downward spiral of progressive cardiac deterioration.
Left atrial appendage
Is small saclike structure in left atrium that is particularly susceptible for thrombus formation.
-approximately 90% of left atrial thrombi are found within LAA in patients with nonvalvular atrial fibrilation
Why verapamil doesnt affect skeletal muscle
Due to the fact that it has little dependence on extracellular calcium influx.
Hydrocephalus, intracranial calcification and chorioritinitis in infant
- its a classic triad of toxoplasmosis.
- hydrocephalus occurs due to CNS inflammation and is evidenced by macrocephaly and enlargement of ventricles.
- chorioretinitis refers to inflammation of the choroids and the retina that can leave cotton like white/yellow scars.
- its transmitted to fetus in utero
Intrapartum infection (during delivery) in infants
- infection with HSV
- opthalamia neonatum refers to neonatal conjuctivitis caused by number of agents such as chlamydia, nisseria and viruses.
Erythropoiesis stimulating agents are associated with
- increased risk for thromboembolic events
- increased blood viscosity as a result of the elevation in red cell mass, many patients develops hypertension, possibly due to activation of EPO receptors on vascular endothelial and smooth muscle cells.
