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Biomedical subjects

J H Kramer

Publications and source records attributed to J H Kramer.

98 records · Page 6Linked to original sources
PubMed1981

Effect of taurine on calcium paradox and ischemic heart failure.

The loss of mechanical function in rat hearts subjected to either the calcium-paradox or global ischemia heart failure models was found to correlate with decreases in myocardial taurine levels. Therefore, the effect of taurine treatment was assessed in the two failure procedures. The presence of taurine protected against loss of mechanical function resulting from the calcium paradox and prevented both the large decline in sarcolemmal ATPase activities and the increase in sarcolemmal calcium binding normally associated with this model. Parallel studies on reperfused, taurine-untreated ischemic hearts showed only minor changes in these sarcolemmal functions. Taurine treatment normalized the slight increase in calcium binding associated with ischemia, but had no observable effect on recovery of mechanical function. Although taurine returns selected parameters of the sarcolemma toward normal in both models, it only improves mechanical function in the paradox model. This suggests that calcium paradox-induced heart failure is more closely associated with sarcolemmal dysfunction than ischemic heart failure.

Adenosine Triphosphatases↗
PubMed1968

Cellular immunity in vaccinia infection of mice. Anti-thymocyte serum effects on primary and secondary responsiveness.

Rabbit anti-mouse thymocyte serum suppressed host cell-mediated responsiveness to intravenously administered vaccinia virus, thereby augmenting the morbidity and mortality of this infection. It did not affect either humoral antibody or interferon production in response to vaccinia virus. No effects were noted on primary or secondary immunity to intracerebral virus inoculation.

Animals↗
PubMedDate not supplied

Uncoupling of mitochondrial oxidative phosphorylation alters lipid peroxidation-derived free radical production but not recovery of postischemic rat hearts and post-hypoxic endothelial cells.

The contribution of mitochondrial free radical production towards the initiation of lipid peroxidation (LPO) and functional injury in the post-ischemic heart is unclear. Using the isolated rat heart model, the effects of the uncoupler of mitochondrial oxidative phosphorylation dinitrophenol (DNP, 50 microM final) on post-ischemic lipid peroxidation-derived free radical production and functional recovery were assessed. Hearts were subjected to 30 min total global ischemia followed by 15 min of reperfusion in the presence of DNP. As expected, DNP enhanced oxygen consumption before (11.3 +/- 0.9 mumol/min, p < 0.001) and during reperfusion (at 10 min: 7.9 +/- 0.7 mu umol/min), compared to the heart with control treatment (8.2 +/- 0.5 and 6.7 +/- 0.3, respectively). This effect was only associated with a higher incidence of ventricular tachycardia during reperfusion (80 vs. 50% for control treatment, p < 0.05). Electron spin resonance spectroscopy (ESR) and spin trapping with alpha-phenyl-tert-butylnitrone PBN-radical adducts (untreated: 6.4 +/- 1.0 nM, at 10 min) decreased in the presence of DNP (1.7 +/- 0.4 nM, p < 0.01). The radical concentration inversely correlated with myocardial oxygen consumption. Total liberation of free radical adducts during the initial 10 min of reperfusion was reduced by DNP (0.59 +/- 0.09 nmol, p < 0.01) compared to the respective control treatment (1.26 +/- 0.16 nmol). Similar effects, prevention of PBN adduct formation and unchanged viability in the presence of DNP, were obtained with endothelial cells during post-hypoxic reoxygenation. Since inhibition of mitochondrial phosphorylation can inhibit the formation of LPO-derived free radicals after an ischemic/hypoxic interval, mitochondria may represent an important source of free radicals capable of initiating lipid peroxidative injury during reperfusion/reoxygenation.

2,4-Dinitrophenol↗
PubMedDate not supplied

Chemotherapeutic CNS prophylaxis and neuropsychologic change in children with acute lymphoblastic leukemia: a prospective study.

OBJECTIVE: To determine whether prophylactic CNS chemotherapy for childhood acute lymphoblastic leukemia is associated with declines in neuropsychological abilities. METHODS: Growth curve analysis was used to examine neuropsychological outcome and treatment-related change in children (N = 30) who were treated at two childhood cancer centers. A comprehensive test battery was administered at baseline (8 months), 2, 3, and 4 years postdiagnosis (age at diagnosis M = 5.90 years, SD = 4.2C). RESULTS: Results indicated modest declines in arithmetic, visual motor integration, and verbal fluency. Intrathecal and systemic treatment was related to poorer visual motor integration at 4 years postdiagnosis and a faster rate of decline in visual motor integration skills across the observation period than intrathecal treatment alone. Arithmetic proficiency at 4 years after diagnosis was related to maternal education, but the rate of decline was not. Verbal fluency was unrelated to demographic or treatment variables. CONCLUSIONS: These findings suggest that neuropsychological outcome and declines are related to both demographic and treatment characteristics depending on the cognitive domain examined.

Antineoplastic Agents↗
PubMedDate not supplied

Aphasia, apraxia, and agnosia in the diagnosis of dementia.

The association of aphasia, apraxia and agnosia with cortical but not subcortical dementias, is a widely held belief. The purpose of the present study was to determine the frequency of aphasia, apraxia, and agnosia in groups of cortical and subcortical dementia patients, and to assess the diagnostic utility of these symptoms. Subjects were 64 patients with subcortical dementias (Parkinson's disease and normal pressure hydrocephalus) and 192 patients with cortical dementia (probable Alzheimer's disease) matched for sex, age, and Mini-Mental State Examination score. Each patient was evaluated for the presence of aphasia, apraxia, and agnosia. Results indicated that only aphasia was reported significantly more often in cortical dementia patients than in subcortical dementia patients. The presence of either of these three symptoms has very low diagnostic sensitivity, specificity, and total predictive value. The severity of the patient's dementia was predicted whether the patient had aphasia or apraxia; type of dementia had no predictive value. These data led to the conclusion that cortical and subcortical dementias cannot be reliably dissociated on the basis of aphasia, apraxia, or agnosia.

Aged↗