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Biomedical subjects

M Lambert

Publications and source records attributed to M Lambert.

At least 361 records · Page 20Linked to original sources
PubMed1985

Mechanisms of multistage chemical carcinogenesis and their relevance to respiratory tract cancer.

The evolution of a fully malignant tumor is a multistep process resulting from the action of multiple factors, both environmental and endogenous, and involves alterations in the function of multiple cellular genes. Chemical carcinogens that initiate this process appear to do so by damaging cellular DNA. In addition to producing simple point mutations, this damage appears to induce the synthesis of a transacting factor that can induce asynchronous DNA replication. This response may result in gene amplification and/or gene rearrangement. This phenomenon may also play a role in synergistic interactions between chemicals and viruses in the causation of certain cancers. The primary target of the tumor promoters TPA, teleocidin, and aplysiatoxin appears to be cell membranes. All three of these agents act, at least in part by, enhancing the activity of the phospholipid-dependent enzyme PKC. We have proposed a stereochemical model to explain the interaction of these amphiphilic compounds with the PKC system. We have found that TPA and teleocidin markedly enhance the transformation of C3H10T1/2 mouse fibroblasts when these cells are transfected with the cloned H-ras human bladder cancer oncogene. Thus, tumor promoters can act synergistically with an activated oncogene to enhance cell transformation. Furthermore, carcinogen-transformed rodent cells display aberrations in the expression of various endogenous retrovirus-related sequences. Activation of some of these sequences may lead to insertion mutations and further aberrations in gene expression. These findings are discussed in terms of a multistep model that involves progressive changes in cellular oncogenes and aberrations in the function of DNA transcription enhancer sequences. It will be of interest to determine to what extent these concepts apply to the etiology of cancers of the respiratory tract.

Animals↗
PubMed1985

[Tubular involvement during non-oliguric rhabdomyolysis. (Apropos of 2 cases)].

The authors report two cases of severe rhabdomyolysis in a 23-year-old woman following a toxic coma with muscular compression and in a 34-year-old man after a febrile state. Despite clinical and biological signs of marked muscular necrosis, oliguric acute renal failure did not occur. However, repetitive urinary dosage of N-acetyl-glucosaminidase (NAG), of retinol-binding-protein (RBP) and of beta-2-microglobulin (beta-2-m) revealed an early and long-standing tubular dysfunction not suggested by conventional laboratory data.

Acetylglucosaminidase↗
PubMed1985

[Thyroid hormones during a hypocaloric diet in obese patients].

The levels of T3, RT3, T3/RT3, T4, FT4 index or T4/TBG, TSH, at days 1, 4, 8, 15 of a 800-1 000 diet with 60-80 g of carbohydrates, were studied in 45 subjects. Statistical analysis was performed using parametric and non parametric tests for comparison of the mean levels between days 1 and 4, 1 and 8, 1 and 15, 4 and 8, 4 and 15, 8 and 15. We observed no difference between men and women. We noted no modification in the evolution of T4, FT4 or T4/TBG and TSH levels. A significant T3 decrease and a RT3 increase with a clear cut decrease of the T3/RT3 ratio from day 1 to 15 principally marked from day 4 to 15 were found. These hormonal modifications correlate well with the weight fall.

Adolescent↗
PubMed1985

[Gonorrhea and pustules of the hands].

Two similar cases of disseminated infection by Neisseria gonorrhoeae were observed at the same time. The patients presented with fever, arthralgia, tenosynovitis, cutaneous pustules of the extremities. In one case, N. gonorrhoeae has been recovered from vaginal discharge; in the other, bacteriological investigations failed. From a review of the literature, it appears that: (1) acral vesiculo-pustular lesions and tenosynovitis represent the most suggestive signs of the disease; (2) it is obviously important to repeat the bacteriological investigations; (3) biological data, included serology, are useless. However, immunofluorescence techniques might detect altered germs in the skin.

Adult↗
PubMed1984

One-step isocratic high-performance liquid chromatographic purification of radioiodinated and radioiodinated-photoactivable derivatives of cholecystokinin.

N-Hydroxysuccinimidyl-3-(4-hydroxy-3-[125I]iodophenyl)propionate (the Bolton-Hunter reagent) was conjugated with (Thr 34, NLeu 37) cholecystokinin (CCK) 31-39 in anhydrous dimethylformamide-pyridine in 20% yield. The radiolabelled peptide was purified from the reaction mixture in one step, by isocratic elution from a C18 high-performance liquid chromatographic (HPLC) column with 35% aqueous acetonitrile-0.13% heptafluorobutyric acid as eluent. The concentration of the radiolabelled peptide was estimated by UV monitoring. The acylating photoactivable radioiodinated reagent N-hydroxysuccinimidyl-N-(4-azido-2-nitrophenyl)-3-[125I]iodotyrosi ne was synthesized, purified on a C18 HPLC column by isocratic elution with 65% acetonitrile-1 mM hydrochloric acid, then conjugated with (Thr 34, NLeu 37) CCK31-39. The resulting photoactivable radioiodinated CCK analogue was purified by isocratic elution on a C18 HPLC column with 39% aqueous acetonitrile-0.1 M triethylamine phosphate (pH 3.5). The binding ability of both tracers and their non-radioactive analogues to CCK receptors was tested on rat pancreatic plasma membranes. As compared to a KD of 4.5 nM for unmodified (Thr 34, NLeu 37) CCK31-39, the KD of the radioiodinated Bolton-Hunter derivative was 3 nM, and that of the photoactivable radioiodinated derivative was 19 nM.

Animals↗
PubMed1984

Comparison of two methods of prophylaxis against CSF shunt infection.

In a series of 68 operations for insertion or revision of cerebrospinal fluid shunts the incidence of infection was reduced from 20% in controls to 4.2% when systemic and intrathecal or intra-shunt gentamicin prophylaxis was employed. The only infection occurring in the latter group was due to an organism resistant to gentamicin. No reduction in infection rate was noted when povidone iodine was instilled into the wounds.

Cerebrospinal Fluid Shunts↗
PubMed1983

[Treatment of idiopathic thrombopenic purpura with immunoglobulins].

Twelve patients presenting with idiopathic thrombocytopenic purpura were treated with injections of immunoglobulins. A lasting improvement was observed in 1 and a transient improvement in 8. Intramuscular injections appeared to be more effective than intravenous injections. The increase in the number of platelets was accompanied by a decrease of circulating immune complexes. The antigen-antibody reaction observed between the doses of immunoglobulins injected and the patients' sera suggests that immunoglobulins might act by enhancing the elimination of some antigens of infectious origin.

Adult↗
PubMed1983

Management of acute brachial artery occlusion due to trauma or emboli.

Out of 37 patients requiring emergency surgery for upper limb ischaemia, 9 were due to spontaneous embolus, 7 to arterial laceration and 21 followed cardiac catheterization. Eleven of the initial operations (30 per cent) failed to relieve ischaemic symptoms though 6 were corrected by further operations. Success at the initial operation was associated with (i) repair with end-to-end anastomosis after resection, saphenous vein bypass or interposition graft, or generous vein patch, (ii) exposure of the radial/ulnar bifurcation, (iii) instillation of heparinized saline locally or (iv) restoration of the radial pulse at the end of the operation. In the cases studied in whom all the above recommendations were followed, the operation was entirely successful and all patients have a radial pulse and are currently symptom free.

Acute Disease↗