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Biomedical subjects

A Barnes

Publications and source records attributed to A Barnes.

At least 127 records · Page 7Linked to original sources

Insensitivity of bonnet monkeys to (D-Ala6, Des-Gly10) LHRH ethylamide, a potent new luteinizing hormone releasing hormone analogue in rats and mice.

The Luteinizing Hormone Releasing Hormone (LHRH) activity of (D-Ala6, Des-Gly10) LHRH ethylamide was compared with that of LHRH in oöphorectomized bonnet monkeys by determining serum LH and FSH concentrations at various time intervals after a sc injection of 100 mug of LHRH and either 100 mug or 1 mg of the analogue. Following administration of synthetic LHRH, a significant rise in both serum LH and FSH was observed. In contrast, no discernible change in serum gonadotropin concentrations was noted following injection of the analogue (D-Ala6, Des-Gly10) LHRH ethylamide, previously reported to have greatly increased potency in rats and mice.

Animals↗

Neuromuscular block by neomycin in the cat.

The neuromuscular block produced by neomycin is unique. Despite nearly complete blockade of the twitch the tetanus is not blocked and does not fade. The pathognomonic post-tetanic exhaustion has not been reported previously. Anticholinesterases and calcium antagonize the block, but the antagonism may not be complete. Germine antagonizes the block in the cat, but its clinical value has not been tested. These characteristics of neuromuscular block by neomycin strongly suggest respiratory support and sedation to decrease the respiratory drive, rather than attempts at antagonism, as the rational management of patients suffering from toxic paralysis due to neomycin.

Anesthesia↗

Neuromuscular sensitivity to tubocurarine. A comparison of 10 parameters.

The pharmacometrics of neuromuscular block by tubocurarine was studied. Ten parameters were compared for the sensitivity, the scatter and the linearity of response at three levels of block in 11 cats. The fourth twitch of the train-of-four is the most sensitive parameter, followed in order of decreasing sensitivity by the train-of-four fade, the faded tetanus, the tetanus, the single twitch, the post-tetanic twitch and the tetanic fade. At the level of 50% block of the single twitch, all other parameters differ significantly (P less than 0.05) from the single twitch in sensitivity. With the exception of the tetanic fade, all parameters examined correlate with the single twitch (r xy = 0.42-0.77). This permits limited translation of results among various parameters. In cats the scatter of results is least for the most sensitive parameter, and vice versa. We conclude that the train-of-four is the most sensitive parameter, and that the single twitch is valid for an over-all estimation of the neuromuscular block induced by tubocurarine.

Animals↗

A new test for both neutrophil marrow reserves and intravascular survival.

Reinfusion of a patient's own blood through a hemodialysis coil causes neutrophilia, reaching a peak less than 1 hour after starting the blood reinfusion and returning to baseline count over the next few hours, resulting from a transient release of neutrophils from the bone marrow. This report gives data regarding the double clinical utility of so stimulating a patient's marrow. First, we found that the magnitude of this neutrophilia was a good measure of marrow neutrophil reserves, as determined by comparison with the marrow mature neutrophil cellularity. Second, the falloff from peak neutrophilia to baseline count was a good estimate of neutrophil intravascular survival, as determined by comparison with the standard, in vitro, diisopropylfluorophosphate (DF32P) survival procedure. Thus, this one test could detect abnormalities both of marrow neutrophil production (release) and of peripheral destruction. The coil test requires no radioactive isotope, utilizes commonly available equipment, is apparently harmless and acceptable to the patients, and can be greatly simplified by the development of a blood bag containing sterile cellophane. Even in its present form, it offers considerable clinical and economic advantages in the assessment of pathophysiology of neutropenia in individual patients.

Adult↗

Reorganization of a nutrition unit in Papua New Guinea.

Adequate nutrition is a medical priority. It has been estimated that more than half the children in the Chimbu District of Papua New Guinea are malnourished. A practical scheme combat poor nutrition there was based on emphasizing the value of breast-feeding and of locally grown foods. The daily menu given was the same, with three meals each day. The scheme's underlying principles can be adapted for any developing country or for migrant and other minority groups in a developed country.

Anemia↗

Arsenic intoxication as a cause of megaloblastic anemia.

We have described a case of chronic arsenic intoxication associated with pancytopenia and megaloblastic erythropoiesis. The patient had the typical laboratory manifestations of effective erythorpoiesis due to a megaloblastic process, including macroovalocytes, mild pancytopenia, low reticulocyte index, increased marrow cellularity with erythroid hyperplasia, and morphologic evidence of megaloblastic maturation in the marrow. The patient's serum folate and vitamin B12 were normal, and the anemia regressed without therapy. Our case suggests that the combination of megaloblastosis with normoblastic or megaloblastic karyorrhexis,should raise the suspicion of arsenic intoxication in the mind of the observer. In addition, arsenic should be added to the list of agents causing a reversible megaloblastic anemia.

Anemia, Macrocytic↗