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Biomedical subjects

J Norman

Publications and source records attributed to J Norman.

At least 163 records · Page 9Linked to original sources
PubMed1988

Red blood cell and plasma fatty acid composition in diabetes mellitus.

Arachidonic acid deficiency and increased linoleic acid levels have been a consistent finding in a variety of tissues in experimental diabetes. To determine if patients with type II non-insulin-dependent diabetes show changes in red blood cell and plasma fatty acid composition, a group of non-insulin-dependent diabetic patients were studied prior to and following treatment with glyburide which substantially improved their diabetic control. Red blood cell and plasma fatty acid composition was compared with that of a group of nondiabetic subjects and to red cell fatty acid composition in normal and streptozotocin diabetic rats. The diabetic patients had no changes in linoleic or arachidonic acid levels prior to treatment and no changes following glyburide therapy. These studies and the available literature suggest to us that either more severe diabetes is required to produce the fatty acid abnormalities described in the diabetic rat or that there is a fundamental species difference in the mechanism of diabetes or in fatty acid metabolism between the human and the rat which allows the human diabetic to more easily maintain normal tissue fatty acid composition.

Diabetes Mellitus, Type 2↗
PubMed1988

Frames and images: sequential effects in mental rotation.

Recent studies have shown that response time in mental rotation increases with the angular deviation between the current and preceding stimuli, suggesting a frame rotation process in which the intrinsic frame of the previous stimulus is brought into congruence with the coordinates of the current stimulus. In contrast, we show that this process involves image rotation in which the present stimulus is brought into alignment with the orientation of the previous stimulus. Such "backward alignment" succeeds only for shape-preserving sequences (i.e., identical stimuli at different orientations). Four experiments show that the backward alignment process (a) competes with the uprighting process typically found in mental rotation, and the response is determined by the process requiring the shortest rotational path; (b) is related to the tendency to repeat the previous response; (c) is insensitive to the position of the vertical; (d) is indifferent to the representation of the stimulus in long term memory; and (e) is different from the process underlying preparation for a stimulus in a specified orientation.

Attention↗
PubMed1988

Effect of suxamethonium given during recovery from atracurium.

Suxamethonium was given in varying doses when twitch response had returned to 50% of control following the administration of atracurium in anaesthetized patients. Small doses of suxamethonium produced antagonism, enhancement of the block, or a combination showing a biphasic response. A dose of 3 mg kg-1 was needed to produce consistently 100% block of the twitch. The subsequent recovery rate for T1 was as fast as that seen normally after suxamethonium and was not enhanced by neostigmine.

Adolescent↗
PubMed1988

A comparison of midazolam and temazepam for premedication of day case patients.

One hundred patients who underwent day case surgery took part in a randomized double-blind comparison between midazolam 15 mg and temazepam 20 mg orally as premedicants. Postoperative recovery was studied using tests of psychomotor function. Midazolam produced a similar degree of anxiolysis to temazepam and a greater incidence of drowsiness. Recovery was similar after either premedicant and psychomotor function was still depressed 4 hours postoperatively (p less than 0.001). Nearly 90% of patients felt that they had benefitted from either premedicant. We conclude that midazolam is a suitable drug for premedication in day case surgery.

Adolescent↗
PubMed1988

Propofol: clinical strategies for preventing the pain of injection.

Eight modes of administration of propofol were assessed in order to minimise the pain of injection. An intravenous bolus injection in the antecubital fossa was the only approach that caused no pain. When administered intravenously in the dorsum of the hand the pain score and the number of patients who experienced pain was reduced significantly by mixing the agent with lignocaine when compared with a bolus injection. Slowing the speed of injection caused the greatest discomfort. An indirect biochemical mechanism for the pain is proposed.

Adolescent↗
PubMed1987

Bulimia. An underlying behavioral disorder in hyperlipidemic pancreatitis: a prospective multidisciplinary approach.

Between 1978 and 1985, we conducted a prospective study of 21 patients who survived several attacks of pancreatitis and were diagnosed as having primary hyperlipidemia. None of the patients suffered from chronic alcoholism, primary diabetes, or cholelithiasis or was receiving prolonged steroid therapy. Lowering of plasma lipid values toward normal was achieved in all patients following a program of combined dietary and drug (bezafibrate) therapy. Five patients had recurrent episodes of pancreatitis during the treatment program. These patients were diagnosed subsequently as suffering from bulimia and were all given cognitive behavioral therapy. One patient died following an attack of pancreatitis. An underlying eating disorder should be suspected in patients who relapse after treatment for pancreatitis and hyperlipidemia. Multidisciplinary treatment should be used in these patients to improve therapeutic efficacy and uncover behavioral patterns that have a direct impact on their life expectancy.

Adult↗
PubMed1987

Spatial frequency filtering and target identification.

Twenty subjects identified filtered pictures of previously learned target stimuli. Five filters were utilized: 3 two-octave wide band-pass and 2 complementary (same cutoff) high- and low-pass. Response times and per cent errors were used to assess performance. The filtered pictures were presented at two sizes: to ten subjects at twice the size presented to the other ten. The results indicated that higher spatial frequencies contribute more to the identification task than do the low spatial frequencies, but also that neither low nor very high frequencies are redundant for identification. It was also seen that both the proximal (c/deg) and the distal (c/picture) scales of spatial frequency measurement are involved in the identification process.

Adolescent↗
PubMed1987

EGF-induced mitogenesis in proximal tubular cells: potentiation by angiotensin II.

The mitogenic effect of epidermal growth factor (EGF) and the characteristics of EGF binding were studied on primary cultures of rabbit proximal tubular cells. EGF was found to be a potent mitogen and stimulated DNA synthesis 18-fold above the level observed in quiescent cells. Using 125I-EGF as a ligand, two classes of specific EGF receptors were identified on the proximal tubular cell in culture, i.e., a high-affinity receptor with a dissociation constant (Kd) of 0.3 nM and maximal binding (Bmax) of 1.7 X 10(4) receptors/cell and a low-affinity receptor with a Kd of 1.9 nM and Bmax of 5.3 X 10(4) receptors/cell. Because angiotensin II (ANG II) appeared to possess many properties common to growth factors, we also examined the interaction of ANG II and EGF on these cells. ANG II was not mitogenic, but it potentiated the mitogenic effect of EGF with a maximal effect at 10(-9) M. The dose-response curve of EGF-induced mitogenesis was shifted to the left in the presence of 10(-9) M ANG II, decreasing the approximate half-maximal stimulatory concentration from 3 X 10(-8) to 5 X 10(-9) M. ANG II also stimulated prostaglandin E2 (PGE2) release, but inhibition of basal and ANG II-stimulated PGE2 synthesis had no effect on mitogenesis. ANG II had no effect on the binding of EGF to the high-affinity receptor from 1 to 20 h and did not alter receptor downregulation. ANG II (10(-9) M) had no effect on cell protein content, RNA and protein synthesis, Na+-H+ antiport, and intracellular free Ca2+ concentration. Higher concentrations of ANG II (5 X 10(-8) to 5 X 10(-6) M) led to a rapid and transient dose-dependent rise in cytosolic free Ca2+ concentration. These studies demonstrate that ANG II potentiates EGF-induced mitogenesis at one or more postreceptor steps that may include small changes in cytosolic Ca2+ concentration.

Angiotensin II↗
PubMed1987

Lability of DNA polymerase alpha correlated with decreased DNA synthesis and increased age in human cells.

DNA excision repair and mitogen-initiated blastogenesis in human cells declined in efficiency as an apparent function of decreased DNA polymerase alpha specific activity with increased age of the cell donor. DNA polymerase alpha isolated from fetal cells contained a single, high-specific-activity enzyme form that could not be further activated and that was stable with regard to enzyme activity and affinity for DNA template-primer. DNA polymerase alpha isolated from adult-derived cells contained both low-specific-activity and high-specific-activity forms. The low-activity enzyme form, which showed low affinity of binding to DNA template-primer, was activated by treatment with phosphatidylinositol, 32P-ATP, and phosphatidylinositol kinase, resulting in a 32P-labeled enzyme that exhibited high affinity of binding to DNA template-primer. The activated enzyme was unstable, exhibiting a loss of 32P-label correlated with the loss of both specific activity and high affinity of binding to DNA template-primer. The data suggest that DNA polymerase alpha isolated from adult-derived human cells has low-activity and high-activity forms. Decreased specific activity of DNA polymerase alpha correlated with increased age of the donor appears to be a function of loss of an enzyme activator molecule resulting in diminished ability of the enzyme to bind DNA template-primer.

Adult↗
PubMed1986

Halothane and the liver.

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Chemical and Drug Induced Liver Injury↗
PubMed1986

Respiratory depression after morphine in the elderly. A comparison with younger subjects.

The effects of intravenous morphine (10 mg/70 kg) on the ventilatory response to CO2 were studied in two groups of subjects, young (18-29 years) and old (66-85 years), prior to elective surgery. In both groups morphine caused a significant depression of respiration as judged by a reduction in the slope of the CO2 response curve, a reduction in the calculated ventilation at an end tidal CO2 tension of 7.3 kPa, a rise in resting end tidal CO2 and a rise in the CO2 threshold. There were no significant differences between the two groups in the changes produced by the drug, suggesting that acute respiratory depression after a single intravenous injection of morphine is similar in old and young people.

Adolescent↗