Mitochondrial diseases

All mitochondrial diseases have myopathies with → Blotchy red muscle fibers (on Gomori-Trichrome stain) & Red ragged fibers

1.  MYOCLONIC EPILEPSY WITH RAGGED RED FIBERS (MERRF)

  • Mycoclonic epilepsy triggered by startle/exercise
  • Proximal muscle weakness

2. LEBER HEREDITARY OPTIC NEUROPATHY (LHON)

  • Bilateral vision loss

3. MITOCHONDRIAL ENCEPHALOPATHY WITH STROKE LIKE EPISODES (MELAS)

  • Seizures and stroke like episodes
  • Muscle weakness
  • ↑ Lactate

Bloom Syndrome

  • Autosomal Recessive
  • Mutation in BLM gene in chromosome 15.
  • BLM gene codes for a DNA Helicase protein. Malfunctioning helicase results in defective DNA replication.
  • Physical characteristics: SHORT STATURE + BIRD LIKE FACIES + SMALL MANDIBLE + BUTTERFLY SHAPED RASH ON CHEEKS + TELANGIECTASIAS + HYPOGONADISM
  • Immunodeficiency: recurrent infections due to ↓ levels of IgA and IgM.
  • ↑ed susceptibility of malignancies (avoid sun exposure)

 

Foods associated with different Micro-organism infections

Bacilus cereus———Reheated rice, Chinese restaurants

Clostridium botulinum——–Honey (spores); Improperly canned foods (toxins)

Clostridium perfringens——–Reheated meat dishes

Listeria monocytogenes——–Unpasteurized milk, Soft cheese

E. coli O157:H7——–Under-cooked meat, beef patties

Salmonella typhi——–Poultry, meat and eggs

Staphylococcus aureas——–Potato salad, mayonnaise, custard

Brucella——–Unpasteurized goat milk

Yersinia enterocolitica——–Unpasteurized milk, pet feces (cold climates)

Cryptosporidium——–Under-cooked meat, contaminated water

Vibrio parahemolyticus/vulnificus——–Contaminated seafood

(Vibrio vulnificus can also cause wound infection from contact with contaminated water or shellfish)

Protein Synthesis Inhibitor Antibiotics Mechanisms of Action

INTERFERE WITH FORMATION OF INITIATION COMPLEX

Aminoglycosides (30S Subunit) [AGs also cause misreading of code by causing shift in reading frame that is why AGs are the only protein synthesis inhibitors that are Bactericidal; all the other are Bacteriostatic i.e they stop the increase in number of bacterias and then the body defense mechanisms are better able to fight them off.]

Linezolid (50S Subunit)

BLOCK THE AMINO ACID INCORPORATION TO A-SITE

Tetracyclines (30S Subunit)

Dalfopristin/Quinopristin (50S Subunit)

BLOCK THE FORMATION OF PEPTIDE BOND BY INHIBITING PEPTIDYLTRANSFERASE

Chloramphenicol (50S Subunit)

INHIBIT TRANSLOCATION OF PEPTIDYL tRNA

Macrolides (50S Subunit)

Clindamycin (50S Subunit)