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What is the pathogenesis of a disease that causes:
mental retardation, growth retardation, seizures, fair skin, eczema, musty body odor.
DX: via heel prick test of neonate 2-3 days after birth.
- Decrease phenylalanine hydroxylase or tetrahydrobiopterin cofactor. -> increase phenylalanine and no tyrosine produced.
How does Hartnup disease lead to diarrhea, dementia, dermatitis, and possible death?
- It is an autosomal-recessive disorder characterized by defective neutral amino acid transporter on renal and intestinal epithelial cells. -> tryptophan excretion in urine and feces.
- No tryptophan leads to no production of niacin (with vitamin B6 as cofactor) -> pellagra.
What autosomal recessive sphingolipidoses lysosomal storage disease leads to:
Hepatosplenomegaly, aseptic necrosis of femur, bone crisis, and macrophages that look like crumpled tissue paper.
- Gaucher's disease
- Deficiency in B-glucocerebrosidase -> accumulation of Glucocerebroside.
What is Chiari II malformation and how does it present?
Cerebellar tonsillar herniation through foramen magnum with aqueductal stenosis and hydrocephaly.
Present with syringomyelia(B/L loss of pain and temperature) and thoracolumbar myelomeningocele.
What are the functions of the 2 embryo genes that are produced at the apical ectodermal ridge.
Wnt-7 gene = necessary for proper organization along dorsal-ventral axis.
FGF gene = stimulates mitosis of underlying mesoderm, providing for lengthening of limbs.
What are the mesodermal derivatives?
Muscle, bone, connective tissue, serous lining of body cavities, spleen, cardiovascular structures, lymphatics, blood, bladder, urethra, vagina, eusctachian tube, kidneys, adrenal cortex, skin dermis, testes, and ovaries.
What teratogen taken by the mother during the 3-8th week of pregnancy will lead to CN VIII toxicity?
Aminoglycosides (gentamicin, tobramycin, streptomycin, etc.)
What is the difference between failure of a urachal duct or vitelline duct to obliterate.
Patent urachus -> discharge of urine
Vitelline fistular -> discharge of meconium (crap)
What is the difference between the mesonephric duct and the paramesonephric duct?
Mesonephric duct (wolffian duct) -> seminal vesicles, epididymis, ejaculatory duct, and ductus deferens.
Paramesonephric duct(mullerian duct) -> fallopian tube, uterus, & upper 1/3 of vagina
What are the male and female derivatives from the urogenital sinus?
- Male: bulbourethral glands =
- Female: Bartholin glands
- Male: Prostate gland =
- Female: Skene's glands
How are the organisms that are stained via silver stain cultured?
Fungi= Sabouraud's agar
Legionella = charcoal yeast extract agar buffered with cysteine
What are the obligate aerobes?
Nocardia, Pseudomonas aeruginosa, Mycobacterium tuberculosis, and Bacillus
What is derived from the 1st branchial arch derivative?
- Meckel's cartilage, mandible, malleus, incus, spheno-mandibular ligament
- Muscles of mastication, mylohyoid, anterior belly of digastric, tensor tympani, tensor veli palatini, anterior 2/3 of tongue.
Nerve: V2 and V3
What is dervied from the 3rd pouch?
- Dorsal wings -> inferior parathyroids
- ventral wings -> thymus
How does the mesonephros and the metanephros conritbute to the kidney system?
Mesonephros is the kidney in the 1st trimester only. Metanephros take control afterwards.
- Ureteric bud(caudal end of mesonephros) -> ureter, pelvises, calyces and collecting duct.
- Ureteric bud induces metanephic mesenchyme to differentiate into glomerulus and renal tubules to distal convoluted tubule.
Why is Aminoglycoside ineffective against Cloustridium, bacteroirdes, and actinomyces?
They are obligate anaerobes that lack catalase and/or superoxide dismutase. They produce CO2 and H2 in tissue.
Aminoglycoside are ineffective because they require O2 to enter the bacterial cell.
What is an endotoxin and what does it do?
- It is a lipopolysaccharide found in the outer membrane of gram negative bacteria.
- activate macrophages
- activate alternate pathway of complement
- activate Hageman factor
What bacteria is bacitracin resistant, catalase negative, and forms a clear area of hemolysis on blood agar?
- This is the B hemolytic, Group B strep (S. agalactiae)
- Causes pneumonia, meningitis, and pneumonia in babies.
What are the diseases seen with an organism that is optochin sensitive, encapsulated, and catalase (-)?
This is streptococcus pneumoniae (a-hemolytic)
- Meningitis (# 1 in anyone above neonate)
- Otitis media
What is the pathogenesis of an organism that causes a patient to present with a grayish-white membrane in their pharynx with cervical lymphadenopathy?
- This is corynebacterium diphtheria
- It inhibits protein synthesis via ADP ribosylation of EF-2.
- Grows on tellurite agar.
- Lab diagnosis via gram positive rods with blue and red granules.