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Biomedical subjects

M Rosenthal

Publications and source records attributed to M Rosenthal.

At least 217 records · Page 12Linked to original sources
PubMed1984

Relationships between aerobic and anaerobic energy production in turtle brain in situ.

To define the relationships between brain mitochondrial activity and high-energy intermediates in the turtle, brains were frozen in situ at times determined by the reduction-oxidation status of cytochrome a,a3. Increases in brain lactate indicated that transition to anaerobiosis occurred while oxidative reactions were still ongoing during hypoxia and that the signal for anaerobiosis is not the complete failure of mitochondrial electron transfer. Decreases in creatine phosphate (CrP), ATP, ADP, and AMP demonstrate that their consumption exceeded production during hypoxia. CrP decreased further during the following 120 min of anoxia, but ATP, ADP, and AMP were not significantly altered from control values. These data suggest that ATP is not inhibitory to rate-limiting, key glycolytic enzymes such as phosphofructokinase. Calculations indicate that ATP production declined during anoxia. This study indicates that decreased CrP values, decreased ATP production, and high lactate levels do not preclude ion homeostasis and electrical activity of turtle brain and that this brain is protected against lactate or pH damage during anoxia, in contrast to mammalian brain.

Adenine Nucleotides↗
PubMed1984

The efficacy of flurbiprofen versus piroxicam in the treatment of acute soft tissue rheumatism.

Fifty patients suffering from acute soft tissue rheumatism entered an open parallel group study of flurbiprofen 200 mg to 400 mg daily versus piroxicam 20 mg to 40 mg daily for 4 weeks. Both treatments caused statistically significant improvements in pain, pain on active movement, restriction of passive movement and reduction of strength. Global assessments of the patients' progress also improved significantly with both compounds. Flurbiprofen was significantly superior to piroxicam with regard to relief of pain at Day 28, pain on active movement at Days 14 and 28, pain on passive movement at Days 7, 14 and 28 and pain, as measured by a visual analogue scale, at Day 14. Clinically, flurbiprofen showed greater improvements in all the other parameters throughout the study period. Side-effects, mainly gastro-intestinal in nature, occurred in 6 patients receiving flurbiprofen and 8 receiving piroxicam. One patient receiving flurbiprofen was withdrawn due to stomach pain and headache, but no withdrawals due to side-effects were necessary in those receiving piroxicam. One patient receiving piroxicam was withdrawn due to a total remission by Day 14.

Anti-Inflammatory Agents↗
PubMed1983

[Cellular immunity in chronic polyarthritis: the effect of basic therapy on T-lymphocyte subpopulations].

Monoclonal antibodies were used to determinee the various T-lymphocyte subpopulations in 51 patients with rheumatoid arthritis (RA). The findings were compared with an age-matched healthy control population. Patients with active rheumatoid arthritis display a significant decrease in suppressor T lymphocyte subsets as compared with RA-patients with inactive disease. The calculated immunological ratio (helper-suppressor ratio) is accordingly higher than in the inactive disease state or in normals. Remission-aimed therapy with slow-acting agents such as gold salts. D-penicillamin, levamisole or azathioprine induces not only a clinical improvement but also normalization of the immunological ratio. These findings support the hypothesis that immunological imbalance may play a crucial role in the development and perpetuation of rheumatoid arthritis.

Antibodies, Monoclonal↗
PubMed1983

Importance of vascular responses in determining cortical oxygenation during recurrent paroxysmal events of varying duration and frequency of repetition.

Cerebral oxygenation initially increases and later decreases in rats subjected to experimental status epilepticus. In this study, we have compared cerebral oxygen supply and vascular changes during paroxysmal events of different durations and at different time intervals to test the hypothesis that oxygen insufficiency is associated more readily with paroxysmal events of greater intensity. Continuous measurements were made of local changes in cortical blood volume, redox levels of cytochrome a, a3, cortical Po2, and systemic arterial blood pressure during recurrent seizures induced by pentylenetetrazol or bicuculline. In contrast to expectations, systemic and cerebral vascular responses and associated increases in cerebral oxygenation were better maintained during long-duration ictal episodes than during short-duration ictal bursts, interictal spikes, or evoked potentials. Short-duration paroxysmal events were often accompanied by decreases in cerebral oxygenation, whereas long-duration events were still accompanied by increases in oxygenation. Ictal bursts occurring with short interburst intervals caused a more rapid failure of vascular responsiveness than those occurring at longer intervals. These relationships of intensity and frequency of repetition of seizures to changes in vascular responses indicate progressive dissociation of the normally tight couple between neuronal activity, energy demand, and cerebral blood flow during status epilepticus.

Animals↗
PubMed1983

Abnormalities of cerebral oxidative metabolism with aging and their relation to the central noradrenergic system.

Cerebral oxidative metabolism was studied in vivo by monitoring redox shifts of cytochrome c oxidase in response to direct electrical stimulation of the cerebral cortex in Fischer-344 rats at 3 and 28 months of age. Such activation results in a transient oxidation of cytochrome oxidase associated with brief increase in local cerebral blood volume. In aged rats, the rates of the transient redox responses of cytochrome oxidase (i.e. initial oxidation followed by re-reduction) are slowed by about 50% in comparison to young rats. Cortical norepinephrine was similar in both age-groups. However, while depletion of cortical norepinephrine causes slowing of the rate of re-reduction in young rats by about 50%, such depletion had no effect on the already slow kinetics of the redox shifts of aged rats. Vascular reactivity to increased metabolic demands, defined by the amplitude ratio of the blood volume increase to the cytochrome oxidation, is increased with age but attenuated by norepinephrine depletion in both age-groups. These results suggest that: (1) cerebral cortical levels of norepinephrine do not decline with age in the Fischer-344 rat; (2) development of an age-related impairment in the capability of cerebral oxidative metabolism to respond to conditions of heightened metabolic demands; (3) such impairment is not worsened by depletion of cerebral norepinephrine; (4) exaggerated vascular reactivity to increased metabolic requirement in aging indicates decreased provision of oxygen and metabolic substrates, and (5) this vascular reactivity is mediated by central noradrenergic mechanisms.

Age Factors↗
PubMed1983

Oxidative metabolic responses during recurrent seizures are independent of convulsant, anesthetic, or species.

A transition from sufficient to insufficient cerebral oxygenation has been reported during recurrent seizures, but it was unknown whether this phenomenon was limited to particular species, anesthetics, or convulsant agents. Focal measurements were made of cortical PO2 and redox changes of cytochrome a, a3 in rats and cats anesthetized with sodium pentobarbital, nitrous oxide, or ketamine, or decerebrated. Seizures were induced with pentylenetetrazol, bicuculline, or electroconvulsive shock. Transition from oxygen sufficiency to insufficiency always occurred in association with inadequate vascular responses, regardless of experimental conditions. These results indicate that transition is a general characteristic of experimental status epilepticus.

Anesthetics↗
PubMed1983

Asbestos in water supplies of the United States.

The review of available data on the concentrations of asbestos in U.S. water supplies suggests that the majority of water consumers are not exposed to asbestos concentrations over 1 million fibers/Liter. A few populations, however, may be exposed to concentrations over 1 billion fibers/L. Of the 538 water supplies for which waterborne asbestos data are available, 8% have concentrations of fibers over 10 million fibers/L. The vast majority of asbestos fibers found in U.S. water supplies are under 5 micron in length.

Asbestos↗
PubMed1983

A corporation-based computerized preventive dentistry program.

A pilot dental program providing diagnostic and preventive services within a corporation has been in operation for two years at the Johnson & Johnson Dental Products Co. The charting system is computerized, allowing automatic problem lists and preventive progress sheets to be generated. Patients are encouraged to see their dentists for treatment of all problems diagnosed. Initial data have demonstrated a significant improvement in periodontal health and a significant reduction in carious lesions. The dental awareness of the participants has been greatly improved and a majority are receiving comprehensive dental care. This demonstrates the effectiveness of this program in which the focus is on oral health through dental diagnosis and prevention.

Computers↗
PubMed1983

Demonstration of a relationship between level of physical training and insulin-stimulated glucose utilization in normal humans.

The relationship between level of physical training and in vivo insulin-stimulated glucose utilization was investigated in 33 healthy nonobese subjects. Status of physical training was estimated by maximal oxygen consumption (VO2 max) during graded bicycle ergometry, and insulin action by the insulin clamp technique. Within the study population we defined a significant (r = 0.63, P less than 0.001) correlation between these two variables. This relationship was independent of age and obesity and accounted for over 40% of the variance in insulin-stimulated glucose utilization among these subjects. In addition, significant correlations existed between VO2 max and the plasma glucose (r = -0.35, P less than 0.05) and insulin (r = -0.37, P less than 0.05) responses to an oral glucose load. These results suggest that differences in level of physical training play a regulatory role in control of in vivo insulin action.

Adult↗
PubMed1982

[Granulocytotoxic antibodies in levamisole-induced agranulocytosis].

Among 98 patients with rheumatoid arthritis who were treated with the immunomodulating agent Levamisole 7 patients developed an agranulocytosis. The ethiology of the Levamisole induced agranulocytosis (LIA) is unknown however circulating granulocytotoxic antibodies are present in the sera of such patients. Routine examination of sera from Levamisole treated patients reveal that such antibodies can be detected several weeks before agranulocytosis in the peripheral blood occurs. Our observation suggest that circulating granulocytotoxic antibodies may play a significant role in the development of LIA and that determinations of such antibodies can provide an excellent tool for the early detection of high risk patients. Routine determinations of such antibodies will allow to increase the safety of this potent agent used in the treatment of rheumatic diseases and Tumors.

Adult↗
PubMed1982

The raphe neuronal system and serotonergic effects of LSD.

Earlier work from this laboratory had shown that LSD caused significant increases in rat brain serotonin (5-HT). The increase was later localized to a subsynaptosomal fraction consisting largely of synaptic vesicles. However, the source of the increase and the mechanism by which LSD caused the enhanced 5-HT binding or retention had not been elucidated. The present study was undertaken to evaluate the serotonergic effects of LSD following destruction of raphe nuclei with radiofrequency lesions. When LSD was given to animals with large midbrain raphe lesions, it caused significant increases in forebrain of cortical 5-HT up to 48 hr, or 7 days post-lesion, respectively. It was concluded that an intact cell body is not necessary for the expression of the LSD-mediated increases in 5-HT occurring in the nerve-ending. The possible mechanisms by which LSD could act directly at the nerve-ending are discussed.

Animals↗
PubMed1982

Ethanol and acetaldehyde alter brain mitochondrial redox responses to direct cortical stimulation in vivo.

To determine whether and how ethanol and acetaldehyde alter brain oxidative metabolic activity, reduction/oxidation shifts of components of the mitochondrial respiratory chain were optically measured, in situ, from cat cerebral cortex. Oxidative shifts of nicotinamide adenine dinucleotide (NADH) were recorded in response to increased energy demand provoked by stimulation of the cortical surface by electrical pulses. Ethanol or acetaldehyde did not alter the direction of the responses but each slowed the rates of oxidation with little effect upon the rates of subsequent re-reduction. There was no apparent change produced by either drug upon the kinetics of the negative shifts of the cortical steady potential in response to the stimulation. However, stimulus-evoked electrical and metabolic responses were decreased in amplitude with increasing drug doses. It is suggested that the slowed mitochondrial oxidation results from inhibition of Na+, K+-ATPase. This supports the concept that ethanol or acetaldehyde inhibit the processes that lead to increased oxygen consumption following cell depolarization in vivo, as has been demonstrated in vitro.

Acetaldehyde↗