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Biomedical subjects

G Lambert

Publications and source records attributed to G Lambert.

At least 163 records · Page 9Linked to original sources

A preliminary double-blind study of intravenous nitroglycerin in acute myocardial infarction.

A preliminary double-blind, placebo-controlled study of the effects of a 48-h intravenous infusion of nitroglycerin (NG) in 140 patients with acute myocardial infarction has been carried out. The patients were randomised to placebo or active treatment within 12 h of the onset of symptoms. Those patients treated with nitroglycerin showed a significant reduction on both days in systolic blood pressure, haemoglobin concentration, and packed cell volume. There was also a significant reduction in diamorphine usage in the first 24 h. There was a higher incidence (non-significant) of dysrhythmia in the placebo group despite an increased usage of antidysrhythmic therapy. The mortality rate in the placebo group was 13%, and 7.8% in the active treatment group, but this difference was not significant. At the 3-month follow-up, 83% of treated patients as opposed to 60% of placebo group were able to resume normal or near-normal activities. Preliminary findings suggest that intravenous NG may be useful treatment for patients with acute myocardial infarction and a larger-scale trial is warranted.

Adult↗

The role of actin and myosin in ascidian sperm mitochondrial translocation.

Fertilization-related sperm mitochondrial movement occurs at a rate comparable to other actin-myosin-driven movements and is inhibited by cytochalasin B and N-ethyl maleimide in Ascidia ceratodes sperm. F-actin was demonstrated in the tails and mitochondria using NBD-phallacidin fluorescence. Both actin and myosin were also detected on the mitochondrion and in the tail by indirect immunofluorescence. Western blot analysis verified the presence of these proteins. Boltenia villosa and Cnemidocarpa finmarkiensis also have mitochondrion and tail localized actin and myosin. In the tails of all 3 species the fluorescence takes the form of discrete spots 0.25-0.5 micron apart. Boltenia and Cnemidocarpa sperm have additional actin at the tip of the head and additional myosin at the base of the head. The presence of actin and myosin on the mitochondrion and in the tail supports a means by which the force for mitochondrial movement is generated.

Actins↗

3'-Hydroxy- and (+/-)-3',11-dihydroxy-delta 9-tetrahydrocannabinol: biologically active metabolites of delta 9-tetrahydrocannabinol.

Synthesis of 3'-hydroxy- (7) and (+/-)-3',11-dihydroxy-delta 9-tetrahydrocannabinol (11), metabolites of delta 9-THC, is described. Condensation of the monoterpene (+/-)-cis-p-menth-2-ene-1,8-diol (1) and (+/-)-3'-acetoxyolivetol (2) in the presence of fused ZnCl2 in CH2Cl2 gave a mixture from which the delta 9-THC derivative 3, containing small amounts of the delta 8-isomer 4, was isolated after column chromatography. This mixture was separated as their diacetates 5 and 6 by high-pressure liquid chromatography. Alkaline hydrolysis (5% KOH in MeOH) of 5 furnished the metabolite 7. Condensation of (+/-)-8 with 2 in the presence of p-toluenesulfonic acid gave 9a, which was acetylated to 9b. Treatment with HgO/BF3 X Et2O in wet THF gave the aldehyde 10. Reduction with LiAlH4 furnished the metabolite 11. These metabolites were compared with delta 9-THC for their ability to depress spontaneous activity and rectal temperature in mice and for their effects on overt behavior in dogs. 3'-Hydroxy-delta 9-THC was also compared to delta 9-THC in the mouse sympatomatology test and cardiovascular system in dogs. The metabolites produced pharmacological effects similar to those of delta 9-THC in all tests. 3'-Hydroxy-delta 9-THC was 2-3 times more effective than delta 9-THC in the behavioral tests, whereas (+/-)-3',11-dihydroxy-delta 9-THC was approximately 3 times less active than delta 9-THC.

Animals↗

Rheumatoid arthritis in a Chippewa Band. I. Pilot screening study of disease prevalence.

The Mille Lacs Band of Chippewa Indians in central Minnesota was screened for rheumatoid arthritis, with a 77% completion rate of the reservation census. Rheumatoid arthritis was found in marked excess, namely 6.8% of those evaluated or, minimally, 5.3% of the total band if all persons had been evaluated with no additional cases identified. This relatively closed population thus provides an opportunity to assess genetic and environmental factors of significance in this disease.

Adolescent↗

Inhibition of B cell cytotoxicity by aggregated IgG and immune complexes.

The presence of immune complexes or aggregated IgG in the microlymphocytotoxicity assay may cause inhibition of cytoxity. When HLA-A and-B antigens are the subject of the test the effect is minimal; however, when B cell alloantigens are being examined the effect is marked. The pattern of inhibition in the later case and the fact that B lymphocytes preincubated with immune complexes are resistant to cytotoxic lysis by anti-B cell sera suggests that immune complexes and aggregated IgG inhibit cytotoxicity by prevention of antibody binding rather than by complement consumption.

Antigen-Antibody Complex↗

[Influence of various enzyme inductors and combinations of inductors on DDT residue elimination in rats].

A study was under-taken to investigate the influence of pretreatments with various hepatic microsomal enzyme inducers on the elimination of DDT residues in rats previously contaminated with p,p' -DDT at 5 mg/kg/day, during 20 days. The following inducers were used : phenobarbital (50 a mg/kg/day, i.p.), 3,4-benzopyrene (20 mg/kg/day, s.c.) and norethandrolone (20 mg/kg/day, s.c.), all given during 14 consecutive days. Each inducer was administered singly or in combination with the other two according to a 2 X 2 X 2 factorial experiment. The animals were then sacrificed for the measurement of p,p' -DDT, p,p' -DDD and p,p' -DDE residues in the blood, brain, abdominal fat, liver and kidneys. The results show that phenobarbital lowers markedly the concentration of total residues in the fat tissue and brain and that norethandrolone brings about a reduction of the residues in the blood, brain and kidneys, but not in the fat tissue. On the opposite, 3,4-benzopyrene produces an increase of the residues in the brain, liver and kidneys. Phenobarbital thus appears to be more efficacious than the other two inducers in facilitating the elimination of DDT residues from the fat tissue. In addition, it appears that under the experimental conditions used during this investigation, the elimination of DDT residues is not further accelerated by combining the inducers one with each other.

Abdomen↗

Age-dependent resistance to transmissible gastroenteritis of swine. III. Effects of epithelial cell kinetics on coronavirus production and on atrophy of intestinal villi.

Coronavirus titers in small intestine, degree of villous atrophy and apparent rates of regeneration of intestinal villi were compared in newborn, 3-week-old and adult pigs for 1 week after they were exposed to the transmissible gastroenteritis virus of swine. The response within the newborn group was homogeneous, resulting in high virus titers, maximal villous atrophy and comparatively slow regeneration. In general, virus titers were lower, villous atrophy was less severe and regeneration more rapid in both older groups than in the newborn pigs. However, the response varied greatly in the older groups. The 3-week-old group was divided into two populations. The major population had low virus titers and developed partial villous atrophy, whereas the minor population had marked villous atrophy and virus titers comparable to those of the newborn pigs. These observations support the hyposthesis that the accelerated replacement of villous epithelium in the small intestine of pigs during the first 3 weeks contributes to the innate age-dependent resistance to transmissible gastroenteritis. The accelerated replacement of villous epithelial cells in older pigs contributes to resistance in two ways. The increased proliferative capacity of crypt epithelium results in a more rapid regeneration of atrophic villi; and the comparatively young villous absorptive cells resulting from accelerated replacement produce less virus per cell than the older ones of the newborn pig.

Age Factors↗

[The effect of pretreatment with enzyme inducers on the acute toxicity of DDT (1, 1-bis-(p-chlorophenyl)-2,2,2-trichloroethane) in rats].

A study was undertaken to investigate the influence of various hepatic enzyme inducers on the acute toxicity of the organohalogenated insecticide DDT. Adult female rats were pretreated with sodium phenobarbital (50 mg/kg/day during 5 days), 3-methylocholanthrene (20 mg/kg/day during 3 days), and norethandrolone (20 mg/kg/day during 14 days), and were then given 150 mk/kg of DDT per os. Phenobarbital was shown to lower the toxicity of DDT, norethandrolone had the opposite effect, and 3-methylcholanthrene was without any significant effect. After a phenobarbital pretreatment, the cerebral concentration of DDT was lowered, possibly as a result of an increased biotransformation of DDT to DDD in the liver. On the other hand, norethandrolone did not appear to modify the hepatic conversion of DDT to DDD, nor the cerebral concentration of DDT. Further studies are needed to explain the potentiating effect of norethandrolone on the acute toxicity of DDT.

Animals↗

Transmissible gastroenteritis (TGE) of swine: effect of age of swine testes cells culture monolayers on plaque assays of TGE virus.

A continuous line of swine testes cell culture monolayers was infected at various ages with both cell culture-adapted transmissible gastroenteritis (TGE) virus and tissue infected with TGE virus. Both produced increasing numbers of plaques as the cell monolayers aged from two to five days. Therefore, allowing the swine testes cell monolayer to age five to six days before inoculation should increase the likelihood of detecting TGE virus by plaque assay.

Animals↗