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Biomedical subjects

J Martin

Publications and source records attributed to J Martin.

At least 811 records · Page 45Linked to original sources
PubMed1986

Apolipoprotein B mediates the capacity of low density lipoprotein to suppress neutrophil stimulation by particulates.

Low density lipoprotein (LDL) inhibits phagocytosis of certain negatively charged particulates and also inhibits subsequent cellular secretory and oxidative responses to these particulates. In the present work, we have defined the structural features of LDL involved in this activity. Starch-heptane extraction depleted greater than 95% of neutral lipids but had little effect on the capacity of LDL to inhibit monosodium urate crystal- or polystyrene latex bead-induced neutrophil chemiluminescence (CL). Liposomes containing gamma-palmitoyl-beta-oleoylphosphatidylcholine (PC) with unesterified cholesterol (PC:cholesterol = 2:1), PC and sphingomyelin (PC:sphingomyelin = 2.3:1), or PC alone lacked the capacity to inhibit urate-induced CL. However, incorporation of apoB-100 into liposomes via cholate dialysis rendered them nearly as inhibitory for urate-induced neutrophil CL as LDL on a protein weight basis. Moreover, delipidated apoB-100, containing less than 3% residual phospholipid, inhibited neutrophil responses to urate crystals or latex beads (degranulation and superoxide anion release) in a stimulus-specific manner. Modifications of the lysine residues of apoB (e.g. acetylation) reduced both the capacity of LDL to inhibit urate crystal-induced CL and to bind to urate crystals. The effects of apoB lysine residue modification were reversible, proportional to the extent of modification, and were not attributable to alteration of the net charge of apoB. Thus, the apoB-100 of LDL both mediates and shares the capacity of native LDL to inhibit certain neutrophil responses to particulates.

Apolipoproteins B↗
PubMed1986

[Trimetazidine preservation of the energy potential of the myocardium during ischemia and reperfusion. Phosphorus NMR spectroscopy study of the isolated heart].

The effects of trimetazidine on ischaemia-induced metabolic damage were checked by 31 phosphore - nuclear magnetic resonance spectroscopy on the isolated rat heart. Isolated rat hearts, retrogradely perfused (37 degrees C, 9.81 kPa, pH 7.4 bicarbonate buffer) were submitted to partial global ischaemia (24 min, 0.2 ml.min-1 residual coronary flow) or total global ischaemia (12 min no flow). 31 phosphore-nuclear magnetic resonance spectra (132 i, 45 degrees, 101.3 MHz) were taken every 3 minutes. Changes in ATP, phosphocreatine and inorganic phosphore heart contents were followed, and intracellular pH was estimated from the chemical shift or inorganic phosphore. Trimetazidine was added to the perfusion fluid at the beginning of perfusion. The drug was used at two concentrations: 6.10(-7) M which has no effect on the contractility of the heart in normoxic conditions and 6.10(-4) which depresses significantly heart work. When trimetazidine was used at the concentration of 6.10(-7) M, the intracellular acidosis at the end of a 24 min low-flow ischaemia was less than in control hearts (6.6 versus 6). During reperfusion the restoration of the phosphorylation processes (as expressed by the ratio ATP/inorganic phosphore) was accelerated under the effect of the drug. Similar, but more pronounced, effects were observed in a 12 min total ischaemia when trimetazidine was given at a concentration (6.10(-4) M) which induces a reduction of cardiac work. In this case the myocardial ATP content was also protected during ischaemia. Under the effect of trimetazidine the phosphorylation processes are more rapidly restored during reperfusion than in control hearts. The protection of the mechanisms or structures involved in the energy transfers could be due to the reduction, under the effects of trimetazidine, of the intracellular acidosis induced by ischaemia.

Adenosine Triphosphate↗
PubMed1986

Effects of a fish oil supplement on platelet function, haemostatic variables and albuminuria in insulin-dependent diabetics.

A randomised trial of the effects of 15 gm per day of a fish oil supplement (MaxEPA) on blood lipids, haemostatic variables (including platelet function) and albuminuria was undertaken in 41 insulin dependent diabetics. Compared with the control group there was a significant reduction in thromboxane production by platelets stimulated by collagen in vitro in the group who took the fish oil supplement. The extent of platelet aggregation was not altered but the lag phase before aggregation was prolonged. There were also statistically significant increases in plasma LDL cholesterol, fibrinogen and clotting factor X in the group who took the fish oil supplement. No other significant differences were noted.

Administration, Oral↗
PubMed1986

Enhancement of glomerular mesangial cell neutral proteinase secretion by macrophages: role of interleukin 1.

We have examined the ability of rat mesangial cells to regulate neutral proteinase production in vitro. Mesangial cells constitutively produced gelatinase when cultured in serum-free medium, and enzyme production by these cells was inhibited by cycloheximide. Coculture with thioglycollate-elicited rat peritoneal macrophages resulted in enhanced gelatinase production. The increase in enzyme released correlated directly with the number of macrophages added. Conditioned medium from LPS-activated peritoneal macrophages also enhanced gelatinase production in a dose-dependent manner. Fractionation of these macrophage supernatants on Sephacryl S-200 revealed a predominant fraction of gelatinase-enhancing activity in a m.w. range between 10,000 and 20,000. These data suggested that the enhanced mesangial cell gelatinase production was mediated through the action of interleukin 1. This was confirmed by the finding that purified interleukin 1, prepared from LPS-stimulated rat peritoneal macrophages, stimulated mesangial cells to secrete gelatinase in a dose-dependent manner. These findings may be of significance in the understanding of the pro-inflammatory role of macrophages in immune-mediated glomerulonephritis.

Animals↗
PubMed1986

Evaluation by 31P NMR of the effects of acebutolol on the ischaemic isolated rat heart.

We used 31P NMR spectroscopy to study the effect of acebutolol on the metabolic disturbances caused by ischaemia in the isolated rat heart. The intracellular acidosis and high-energy phosphate compound depletion induced by global low-flow ischaemia were significantly attenuated in the presence of acebutolol 2.7 X 10(-5) and 1.35 X 10(-4) M. The drug displayed no significant effect either at the 5.4 X 10(-6) M concentration or when administered as pretreatment to the animals (50 mg X kg-1, 120 and 60 min before isolating the heart). Since acebutolol had no effect on the contractility of the isolated rat heart at the 2.7 X 10(-5) M concentration the present results suggest that the mechanisms through which acebutolol exerts its effects on energy metabolism are not related to a reduction of cardiac work. The possible contribution of the membrane-stabilizing property of the drug is suggested by the fact that high concentrations are needed and that a short pretreatment had no effect.

Acebutolol↗
PubMed1986

Association and transfer functions for analysis of drug binding to proteins.

A global association function is proposed that characterizes the apparent overall equilibrium of drug protein binding. It is defined as a function of the total drug concentration and may be directly calculated from each experimental result. The binding transfer function represents the relative rates of change in the bound and free concentrations from the total concentration. Two applications are presented: one is an investigation of the effect of temperature on binding of salicylic acid to proteins in plasma; and the other is a comparison of the phenomenon in two different biological fluids (protein binding of sodium salicylate in plasma and in synovial fluid).

Blood Proteins↗
PubMed1986

[AIDS: each and every one's responsibility].

AIDS is posing challenges at various public health related levels, epidemiological, clinical, social, ethical, legal. In the current absence of possibilities of curative treatment or of vaccine, it is essential to provide sufficient information on the available preventive measures. Given the increase in the numbers of seropositive persons, and the recognition that heterosexual relations area significant transmission route in case of multiple, illknown partners, the need is to actively promote the sale and use of condoms (male preservatives), in risk situations in general (and not only to homosexuals and drug addicts). Among others, a proportion of youth have dangerous behaviors in this regard. Public health leaders as well as those in the social, educational and political fields must adopt a clear stance encouraging the practice of this preventive measure which, literally, can save one's life.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Ultrasonographic study of gallbladder motility during total parenteral nutrition.

Gallbladder sludge during total parenteral nutrition may be related to abnormal gallbladder motility. To test this hypothesis, gallbladder motility was assessed in 15 parenterally fed patients and in 22 controls using ultrasonography. Parenteral infusion was continuous in 10 cases and cyclic in 5 cases (6 PM to 10 AM). Gallbladder was simulated to a cone and gallbladder volume was calculated after ultrasonographic measurement of the greatest length and diameter. Six to 12 gallbladder volume measurements were performed between 8 AM and 11 PM in the parenteral nutrition group. In controls gallbladder volume was measured hourly between 8 AM and 8 PM. Thus maximal diurnal gallbladder volume and maximal diurnal gallbladder emptying, expressed as a percentage of maximum gallbladder volume, were determined. Maximal gallbladder volume was identical in the two groups. Gallbladder emptying was significantly reduced in parenterally fed patients (p less than 10(-9)) during both continuous and cyclic infusion.

Adolescent↗
PubMed1986

Effects of diltiazem on the energy metabolism of the isolated rat heart submitted to ischaemia: a 31P NMR study.

The possible direct attenuating modification by diltiazem (DZ) 10(-6) M of ischaemia-induced metabolic damage was studied by 31P NMR spectroscopy (at 101.3 MHz) on retrogradely perfused rat hearts submitted to a 24 min, normothermic (37 degrees C), global low-flow ischaemia (1% of the pre-ischaemic spontaneous coronary flow), followed by a 30 min reperfusion. The presence of DZ 10(-6) M altered neither the heart rate and the left intraventricular pressure under normoxic conditions, nor the extent of ATP and CP depletion during ischaemia, whilst the intramyocardial Pi accumulation during ischaemia was significantly reduced (by about 30%). The intracellular acidification induced by ischaemia was initially less in the presence of DZ, but the pH values reached by the end of ischaemia were somewhat lower than in control (albeit not significantly so): 5.85 +/- 0.07 v. 6.00 +/- 0.07 (Means +/- S.E.M.). On reperfusion, DZ-treated hearts exhibited a greater oxidative phosphorylation capacity than did control hearts. Indeed, NMR spectroscopy revealed a prompter, greater and durable rephosphorylation of creatine together with a simultaneous more rapid and furthermore sharp drop in Pi content in DZ-treated hearts. Moreover, although NMR spectroscopy did not reveal any significant difference in ATP alteration on reperfusion in DZ-treated hearts as compared with controls, biochemical measurements indicated slightly higher ATP content at the end of reperfusion and, more particularly, a better recovery of the adenylate charge: 0.81 +/- 0.03 v. 0.72 +/- 0.03, means +/- S.E.M. (Pre-ischaemic value 0.90-0.91). The intracellular pH differed insignificantly from its pre-ischaemic value at the end of reperfusion in DZ-treated hearts (7.08), while remaining below initial values in controls (7.00). From these results, it is inferred that, at relatively low concentration (10(-6) M), DZ exerts a direct beneficial effect on the energy metabolism of the ischaemic heart without preserving high-energy phosphate compounds during ischaemia and, most importantly, without reducing the extent of the concomitant intracellular acidification.

Adenosine Triphosphate↗
PubMed1986

Walking dandruff and Cheyletiella dermatitis.

Two patients presented with pruritus and rash caused by Cheyletiella mites that lived on our patients' cats. Only with veterinary assistance was the correct diagnosis made and effective therapy instituted.

Adult↗
PubMed1986

Exercise-induced hypertension after repair of coarctation of the aorta: arm versus leg exercise.

The etiology of exercise-induced upper limb hypertension after repair of coarctation of the aorta is unknown. We hypothesized that blood flow across the coarctation repair site is a major determinant of such exercise-induced hypertension. Because arm ergometry should produce a smaller increase in descending aortic blood flow than treadmill exercise, we compared the changes in upper limb pressure and the coarctation gradient produced by each type of exercise at equivalent levels of heart rate and peak oxygen consumption in 28 children with repaired coarctation of the aorta. The children were classified into three groups: Group I, resting gradient less than 15 mm Hg and treadmill gradient less than 20 mm Hg; Group II, resting gradient less than 15 mm Hg and treadmill gradient greater than 20 mm Hg; and Group III, resting gradient greater than or equal to 15 mm Hg. Twelve children with no heart disease served as control subjects. All children were exercised to exhaustion with 45 minutes' rest between the two exercise protocols. There were no differences in maximal heart rate and oxygen consumption between the two types of exercise. In all groups, treadmill exercise produced a larger increase in arm systolic blood pressure and arm-leg gradient than did arm exercise. With treadmill exercise coarctation Groups II and III developed a greater rise in both arm-leg gradient and arm systolic pressure than was observed in the control subjects (p less than 0.05). However, with arm exercise, Group III developed a significantly greater rise in both arm pressure and arm-leg gradient (p less than 0.05) than was observed in the control subjects.

Adolescent↗
PubMed1986

Protein losing enteropathy associated with Nippostrongylus brasiliensis infestation and its impact on albumin homoeostasis in rats fed two levels of dietary protein.

Alterations in plasma albumin concentration and gastrointestinal permeability have been investigated in rats infected with the nematode Nippostrongylus brasiliensis and fed adequate or low protein diets. Infection caused only minor changes in growth and food consumption of well nourished rats but resulted in significant reductions in those fed the low protein diet. Animals in both dietary groups were able to mount an immune response beyond day 10 post-infection (p.i.) which caused expulsion of the parasites, but this was less effective in rats fed the low protein food. Uninfected rats fed the low protein diet had significantly lower plasma albumin concentrations than their well nourished counterparts. Animals of both dietary groups showed a progressive reduction in plasma albumin concentration as the infection developed but values returned towards normal as the parasites were expelled. The reduction in plasma albumin concentration was closely associated with increases in gastrointestinal leakage of plasma protein but losses were far greater in the protein deficiency animals. Beyond day 10 p.i. protein loss decreased in both dietary groups and by day 21 p.i. had returned to normal in well nourished animals but not those fed the low protein diet. Intestinal permeability measured by the lactulose:mannitol ratio technique gave similar results to the protein loss data. Permeability increased as the infection progressed then fell as the worms were expelled but remained above control values in infected protein deficient animals. Overall, animals fed the low protein diet were more severely affected by the parasite than were their well fed counterparts.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

[Breast sonography with high-frequency short-focusing transducers].

Since 1984 two high-frequency short-focussed linear transducers have been used for breast sonography at Innsbruck University Gynaecological Clinic. In the study reported here 121 patients with pathologic change in the breast were examined. A significant improvement in diagnosis was achieved: on the one hand because of the improved resolution and distinction of the lesions, and on the other because of the manageability of the transducers and the individually adjustable breast compression. Both perforation of the physiological mammary strata as well as clearly distinguishable tumor ends without echoproof halos were considered reliable indicators of the malignancy of the respective changes.

Abscess↗