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Biomedical subjects

H Tavakoli

Publications and source records attributed to H Tavakoli.

5 recordsLinked to original sources
PubMed1984

Mitochondrial function in shock.

Studies utilizing animal models of circulatory shock have revealed mitochondrial structural and functional damage in the liver, kidney, and brain. Adenosine triphosphate (ATP) synthesis and calcium transport rates of these mitochondria decline significantly during circulatory shock. The specific enzyme functions affected deleteriously by low flow states are the ATP synthetase, adenine nucleotide translocase, and carrier-mediated calcium transport. Other cellular alterations that possibly are responsible for, or are related to, the shock-induced mitochondrial deterioration are discussed. Differences in the mitochondrial responses to endotoxemia and hyperdynamic sepsis are described. Data are presented on the beneficial effects of early glucocorticoid treatment in prevention of mitochondrial functional deterioration during endotoxemia.

Adenosine Triphosphate↗
PubMed1982

Alterations of mitochondrial metabolism and protein concentrations in subacute septicemia.

Male Sprague-Dawley rats were made septic by cecal ligation for a period of 6 days. Sham-operated rats were used as control animals. Septic rats developed gram-negative bacteremia within 18 to 24 h. Blood cultures were positive for Escherichia coli, Proteus spp., and Klebsiella spp. in all cases. Significant loss of body weight was observed in septic rats during the 6-day period, whereas control rats exhibited a steady gain in body weight after the second postoperative day. Liver and muscle mitochondria were isolated and analyzed 6 days after the operation in control and septic rats. Liver mitochondrial cytochrome a(a3), b, and c concentrations were normal in septic rats. Oxygen utilization rates in state 3 (during ATP synthesis) were also within the normal range. State 4 respiratory rates, however, were increased with glutamate and pyruvate as substrates, resulting in low respiratory control ratios in septic rats. Muscle mitochondria from septic rats exhibited several abnormalities: the yield of cytochromes b, c, and a(a3) per gram of tissue was 34% below normal in septic rats. ATP synthesis rates declined significantly with pyruvate as substrate. Respiratory control ratios were below normal with all substrates studied except glutamate. These data are in agreement with previous reports on loss of muscle proteins and abnormalities in energy fuel utilization in septic patients.

Adenosine Triphosphate↗
PubMed1982

In vitro and in vivo association and subcellular distribution of toxic and experimentally modified endotoxin.

Cell association and organ distribution of toxic and experimentally modified endotoxin were compared in whole animals and hepatoma tissue culture (HTC) cells. For both toxic and poly-l-alpha-ornithine mixed endotoxin in vivo, most of the endotoxin becomes associated with the reticuloendothelial system (RES) rich organs. Organ distribution does not change from 1 to 5 h. Significantly less detoxified endotoxin becomes associated with RES-rich organs. Association and nuclear transfer of toxic endotoxin in HTC cells are gradual and time-dependent processes. Plasma treatment increased association of endotoxin with HTC cells. Poly-l-alpha-ornithine (4 micrograms/mL) also significantly increases HTC cell association of endotoxin, and nuclear transfer of endotoxin was similar in principle to the toxic material. Association of detoxified endotoxin with HTC cells is significantly higher than toxic endotoxin and increases with time. In contrast with toxic and poly-l-alpha-ornithine mixed endotoxin, nuclear association of alkaline-treated detoxified endotoxin did not increase significantly during 5 h incubation. Cumulatively, these observations indicate that while tissue culture cells could provide a more controllable experimental system by which to study the fate and pathogenic mechanism of endotoxin at the cellular and subcellular level, HTC cells under the conditions employed herein do not yield binding data which compare favorably with in vivo results. Caution must be exercised when extrapolating in vitro data to the actual in vivo action of endotoxin.

Animals↗
PubMed1976

Transfer of drug resistance factor in Shigella sonnei isolated in Iran.

The pattern of drug resistance and incidence of R-factors were studied in Shigella sonnei strains isolated in Iran. Eighty-nine out of 172 strains (51.7%) were resistant to one or more drugs and multiple drug resistance was more common than single drug resistance. The most predominant pattern of resistance observed was (Tc, Cm, Sm, Su). By mixed cultivation, 85.7% of Shigella sonnei resistant strains isolated on the Central Plateau and 100% of the strains from the caspian littoral transferred at least a part of their resistance pattern to sensitive E. coli K12 F- (gamma). In this experiment, 67.1% of our resistant and 17% of our sensitive strains had colicinogenic properties. No such difference could be observed between R+ and sensitive strains isolated in the Caspian littoral.

Anti-Bacterial Agents↗