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Biomedical subjects

P Ting

Publications and source records attributed to P Ting.

28 records · Page 2Linked to original sources
PubMed1984

Failure to produce germinal matrix or intraventricular hemorrhage by hypoxia, hypo-, or hypervolemia.

Our study with midgestational sheep fetuses failed to support a cause-and-effect relation between marked hypoxia with or without hypo- or hypervolemia and rapid surges of blood pressure and the development of germinal matrix or intraventricular hemorrhage. Twenty-nine percent of fetuses exposed to marked hypoxia concomitantly with manipulations of their blood volume and blood pressure developed widespread cerebral necrosis. However, despite this marked anoxic-ischemic brain injury, none developed any germinal matrix or intraventricular hemorrhage. Rapidly and markedly elevating the blood pressure in these fetuses despite the presumed presence of an impaired autoregulation and a probable elevation of their central venous pressure also failed to cause germinal matrix or intraventricular hemorrhage. Marked hypoxia accompanied by reductions in blood pressure brought about by blood withdrawal produced an 80% delayed fetal mortality but not a single instance of germinal matrix or intraventricular hemorrhage.

Animals↗
PubMed1983

Hypoxic-ischemic cerebral necrosis in midgestational sheep fetuses: physiopathologic correlations.

Thirty-eight midgestational sheep fetuses were exposed 120 min to marked hypoxia. The brains in eight that reduced their mean arterial blood pressure to less than 30 mm Hg were markedly damaged. In these same fetuses the serum lactic acid concentrations were elevated during exposure to hypoxia to excessively high values (greater than 15 mM) and remained elevated for a prolonged period during recovery. Twenty-one fetuses exposed to the same magnitude of hypoxia that maintained their blood pressure unchanged showed less marked elevations of serum lactate concentrations and remained brain-intact. Greater quantities of pentobarbital administered to the ewes during hypoxia seemed to protect the brain from hypoxia and this effect was dose-dependent. Exposure of midgestational sheep fetuses to marked hypoxia associated with reductions in cerebral blood flow due to decreased blood pressure and impaired cerebral autoregulation caused major focal cerebral necrosis.

Animals↗
PubMed1975

Temperature dependence of N-phenyl-1-naphthylamine binding in egg lecithin vesicles.

The temperature dependence of the binding of PhNapNH2 (N-phenyl-1-naphthylamine) to vesicles of egg phosphatidylcholine has been determined. The Arrhenius plot of the association constant exhibits a discontinuity at 20.9 degrees C, some 30 degrees C above the broad phase transition region of the phospholipid. In the temperature range above 20 degrees C, deltaH0 =--6100 cal-mol-1 and deltaS0 = 9.7 e.u.; in the temperature range below 20 degrees C, deltaH0 = 0 cal-mol-1 and deltaS0 = 30.4 e.u. These values are consistent with the view that there are well ordered lipid-lipid bonds below 20 degrees C which are significantly less important above this temperature. The order in the temperature range of 5 to 20 degrees C, though significantly greater than that above 20 degrees C, is still significiantly less than that in the crystalline state.

1-Naphthylamine↗
PubMed1975

Tracheal suction in meconium aspiration.

We performed a retrospective study of the morbidity and mortality rates of 125 infants, born through meconium-stained amniotic fluid, and admitted to the newborn intensive-care unit for observation. A comparison was made of maternal age, history of toxemia, type of anesthesia, duration of analgesia, presence of cord complications, abnormalities of fetal heart rate, duration of meconium staining, birth weight, gestational age, 1 and 5 minute Apgar scores, and type of resuscitation between infants who were symptomatic or asymptomatic in the unit. Forty-three developed respiratory distress (symptomatic) and eight died; 82 were asymptomatic. The only difference between the two groups was a history of immediate tracheal suction in the delivery room. Of 97 infants receiving immediate tracheal suction, 27 became symptomatic and one died--an infant with Down's syndrome and endocardial cushion defect. On the other hand, of 28 infants who did not receive immediate tracheal suction, 16 became symptomatic and seven died of massive meconium aspiration pneumonitis (P less than 0.001). We concluded that in infants born through meconium-stained amniotic fluid, immediate tracheal suction is a safe procedure that significantly lowers the morbidity and mortality rates and produces no further respiratory depression of the infant.

Amniotic Fluid↗
PubMed1975

DNA replication in homogenates of Physarum polycephalum.

Homogenates of Physarum polycephalum incorporate [3H]dATP into nuclear DNA at an initial rate of approximately 15% of the in vivo rate. To attain this level of synthesis, cultures, are homogenized in a medium containing Mg++, EGTA, glucose and spermine. Incorporation is strongly stimulated by the addition of ATP and all four deoxyribonucleoside triphosphates to homogenates prior to incubation. Various inorganic cations other than Mg++ either do not affect synthesis or are inhibitory. Incorporation is inhibited by a nonionic detergent, Triton X-100. DNA synthesis in this cell-free nuclear system is similar in several respects to that which occurs in vivo: (1) The rate of DNA synthesis in the intact organism at a given time in the mitotic cycle is reflected by the level of synthesis in homogenates prepared from cultures at that time of the cycle; (2) DNA strands labeled in vitro exhibit alkaline sucrose density gradient sedimentation properties similar to those of daughter-strand DNA pulse-labeled in vivo; and (3) Homogenates of cultures which were pre-treated with cycloheximide incorporate [3H]dATP at about 60% of the level observed in homogenates of untreated controls.

Adenosine Triphosphate↗
PubMedDate not supplied

Artificial liver.

Explore the source record for details and available documents.

Adult↗
PubMedDate not supplied

Brain injury from marked hypoxia in cats: role of hypotension and hyperglycemia.

The present study identifies several factors that govern brain pathologic response to marked hypoxia. None of 13 cats exposed to 25 minutes of marked hypoxia (FiO2 = 3.4%; PaO2 = 17 +/- 3 mm Hg, S.D.) that maintained mean arterial blood pressure (MABP) greater than 65 mm Hg were brain injured after reoxygenation and long term survival. In contrast, 12 of 13 exposed to the same hypoxia but that experienced reductions in MABP less than 45 mm Hg for 4 +/- 1 minutes developed a pattern of brain injury closely resembling that of humans surviving in a persistent vegetative state after cardiorespiratory arrest. Higher serum glucose and lactate concentrations and lower blood pH values significantly correlated with development of hypotension during hypoxia. Four of 8 cats exposed to 21 minutes of marked hypoxia followed by 4 minutes of 100% N2 breathing that also led to hypotension similarly developed brain injury. Among the hypoxic/hypotensive cats the magnitude of the hyperglycemic response to hypoxia as modulated by 0, 1, or 2 days of preexposure fasting, strongly correlated with occurrence and extent of brain damage. Peak cisterna magna CSF lactate concentrations 10 to 30 minutes into recovery distinguished those animals that remained brain-intact (less than 13 mM) from those that developed brain damage (greater than 15 mM) with 100% accuracy. Seven cats developed delayed cardiogenic shock 3 to 12 hours into the recovery period. This outcome was predicted by blood pH values less than 6.70 shortly after resuscitation while all 27 surviving cats exhibited values greater than 6.80.

Animals↗