Block 8 Flashcards
PD-1 receptor
Programmed death receptor 1 is expressed on the surface of activated T-cells. It binds to its ligand, PD-L1, downregulating the immune response against tumor cells primarily by inhibiting Cytotoxic T-cells. Many types of cancer cells evade the immune system by increasing expression of PD-L1. Monoclonal antibodies against PD-1 have been developed that prevents the binding of PD-1 to PD-L1, this blocks T-cell inhibition, thereby restoring cytotoxic resposne and promoting apoptosis of tumor cells.
- its used in advanced melanoma and types of lung cancer.
Pseudomonas microbiological features
- Motile aerobic gram negative rod
- Non lactose fermenting, oxidase positive
- Produced pyocyanin
- Emits a grapelike fruity odor
- Produced endotoxin (fever, shock) and exotoxin (inactivates EF-2)
Axillary nerve injury
It occurs most commonly in the setting of shoulder trauma(anterior dislocation, proximal humeral fracture).
Patients have sensory loss over the upper lateral arm and weakness on shoulder abduction due to denervation of the deltoid muscle.
Aromatase deficiency
Autsomal recessive disorder that manifests early in embryonal life with high androgen, low estrogen levels in female fetus.
- maternal virilization commonly occurs during pregnancy due to transfer of excess androgen into maternal circulation.
- affected newborn girls have normal internal genitalia and ambiguous or male type external genitalia.
- men with aromatase deficiency have tall stature and osteoporosis but no genital abnormalities.
HIV treatment - anti gp41
Fusion inhibitros – ENFUVIRITIDE
- inhibits HIV fusion with target cell membrane by binding to HIV gp41.
Nephrotic syndrome –> loss of immunoglobulins
Loss of immunoglobulins and low molecular weight component of complement such as factor B make patients with nephrotic syndrome vulnerable to infections especially pneumococcal.
Holoprosencephaly
Embryology: incomplete divison of the forebrain into 2 hemispheres
Etiology: trisomy 13, sonic hedgehog gene mutations, maternal alcohol use.
Clinical features:
mild: closely set eyes (hypotelorism)m clieft lip/palate
Severe: single midline eye (cyclopia), primitive nasal structure, midfacial clefts.
Its an example of “developmental field defect” (also digeorge syndrome) : initial embryonic disturbance leads to multiple malformation by disrupting the development of adjacent tissues and structure within a particular region.
Antibodies reactive with sheep erythrocytes
Hetrophile antibodies- infectious mononucleosis , monospot test
Avascular necrosis(osteonecrosis) causes, clinical, gross and microscopic inspections
Causes:
-thrombotic/embolic occlusion (sickle-cell, desmopressin sickness)
- glucocorticoids
-vascular inflammation/injury
-alcohol abuse
- traumatic fracture
Clinical: pain on weight bearing, decreased range of motion.
Gross: wedged shaped or geographic zones of necrosis, articular cartilages is viable but may be distored or detached from underlting bone
Microscopic: dead bony trabeculae with empty lacunae, necrosis of surrounding adipocytes.
Carotid sinus hypersensitivity
Its triggered by pressure on the carotid sinus by a tight shirt callor.
- the carotid sinus baroreceptros are important in blood pressure control and use arterial wall stretch as an indicator of systemic BP
- the carotid sinus is a dilation of the internal carotid located just above the bifrucation of the common carotid.
- the carotid sinus reflex has an afferent limb : that arised from baroreceptors in the carotid sinus and travels to medullary center via the hering nerve, a branch of glosspharyngeal nerve .
- the efferent limb of carotid sinus, carries parasympathetic impulses via vagus nerve.
Post streptococcal glomerulonephritis , electron microscopy light microscopy
- light: glomeruli enlarged, hyper-cellular.
- immuneflucosrence: granular deposits of IgG, IgM and C3 along basement membrane and in the mesangium (lumpy bumpy appearance )
- electron : electron dense deposits on the epithelial side of basement membrane
Anesthesia in the ischial spine
Is land mark for pudendal nerve block used for anesthesia during vaginal deliveries and for minor surgeries of the vagina and perineum.
Long thoracic nerve injury
Classicaly occurs during axillary lymph node dissection and result in paralysis of the serratus anterior muscle, leading to winging of scapula.
Trapezius weakness symptoms
- Drooping of the shoulder
- Impaired abduction of the arm above horizontal
- Winging of the scapula
- Weakness of sternocleodomastoid may occur if proximal accessory nerve is affected.
- Weakness of arm abduction above horizontal position
Spherical yeast with a thick capsule
Shown on india ink– cryptococus neoformans.
- its present in soil or pigeon droppings .
Psoriasis pathogenesis
- the pathogenesis of psoriasis is complex, involving CD4+ and CD8+, DC and surrounding keratinocytes.
- the interaction among these ,results in production oh TH1 and TH17 type cytokines (including TNF-å,IL-12,IFN-¥,IL-23, and IL-17,) and keratinocytes growth factors –> keratinocytes proliferation, inflammation and angiogenesis.
Bee venom can lead to
Anaphylactic reaction, they contain hyaluronidase, phospholipase and other proteins –> IgE mediated response
NRTI and NNRTI mechanism, HIV Tx
Inhibits HIV DNA synthesis from RNA template by terminating DNA chain allongation.
NRTI: competitive neucleoside /tide RT inhibitor
NNRTI: allosteric RT inhibitor
Axillary nerve - course
- originates from the posterior corrd of the brachial plexus and carries fibers from C5-C6. It courses deep in the axilla below the shoulder joint, then runs through quadrangular space (bounder by superiorly teres minor, laterally humerus, medially lond head of triceps and inferiorly teres major) and along the surgical neck of the posterior humerus. At this point it give rise to motor branches that supply deltoid, and teres minor muscles, and sensory branches that innervates the skin over the lateral shoulder.
Cortisol producing unilateral adrenocortical adenoma can lead to
Unilateral atrophy of the contralateral adrenal gland.
Crigler najjar syndrome I
Autosomal recessive disorder of billirubin metabolism caused by genetic lack of UGT enzyme needed to catalyze bile glucuronidation. When billirubin isn’t correctly enzymatically processed by the liver, unconjugated hyperbillirubinemia develops. Indirect bilirubin levels typically approximate 20-25 mg/dl in these infants, but can rise to as high as 50 mg /dl.
Metabolic pathways involved in pathogenesis of hyperglycemia induced tissue damage
- Advanced glycosylation end products: (AGEs): glucose can nonenzymaitcally attach to proteins and lipids–> reversible glycosylation –> that slowly stabillize into irreversible products.
- under hyperglycemia conditions, AGEs accumulates and facillitate deposition of LDL in blood vessel walls. And inflammatory cell invasion that causes athersclerosis and microangiopathic complications. High glucose in aquous humor –> cataracts. - Polyol pathway overactivity: aldose reductase (glucose –> sorbitol) (which then sorbitol –> fructose). In addition to sorbitol accumulation, aldose reductase consumes NADPH–> depletion –> oxidative stress.
Syringomyelia
- central cystic dilation in the cervical spinal cord enlargs, cuasing damage to ventral white commisure and anterior horns. The ventral white commisure is the site of decussation of the second order lateral spinothalamic tract neurons and the ventral horns are the site of lower motor neuron cell bodies.
- loss of upper extremity pain and tempreture sensation, upper exterimity weakness and hyporeflexoa, lower extermity weaknes and hyperreflexia and kyphoscoliosis.loss of medial laminscus pathway in lower limb (sensation and proprioception), These findings are consistent with syringomyelia.
Spinal accesory nerve , innervates, injury
Its composed of fibers from cranial and cervical nerve roots. Its pure motor nerve that passes through posterior triangle of the neck and provides innervation to sternocleidomastoid and trapezius.
- the trapezius acts to elevate scapula, rotate it upward and stabilize the shoulder.
- the spinal accessory nerve follows a superficial course through the posterior triangle and is vaulnerable to penetrating trauma and iatrogenic injury. (From cervical lymph node dissection).
Antibodies seen in SLE
- ANA: sensitive but not specific
- anti double stranded DNA (anti-dsDNA) antibodies: highly specific for SLE. Only 60% of pts have this (not sensitive)
- Antibodies against small riboneucleotide proteins (anti smith/ anti snRNPs) : 20-30% of patients, also highly specific.
Entacapone mechanism of action
COMT inhibitor that increases the bioavailability of levodopa by inhibiting peripheral methylation. Combining levodopa with entacapone helps increase the plasma half-life of levodopa, producing more stable levodopa plasma concentration and prolonging the therapeutic effect of each dose. COMT inhibitors are used for Parkinson patients with motor fluctuations who are experiencing end of dose wearing off periods with levodopa/carbidopa therapy.
Injury to axillary nerve
Deltoid weakness, impaired abduction of the arm at angles below horizontal plane.
Dubin johnson syndrome
Autsomal recessive disorder charactrized by absence of billiary transport protein, MRP2 (multidrug resistance protein), used in hepatocellular excertion of billirubin into bile caniculi.
The liver is darkly pigmented as a result, but patients typically asymptomatic and suffer no significant side effects.
