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Biomedical subjects

J Martin

Publications and source records attributed to J Martin.

At least 775 records · Page 43Linked to original sources
PubMed1987

Preproenkephalin mRNA in T-cells, macrophages, and mast cells.

The presence of preproenkephalin mRNA in tumor cell lines derived from myeloid and mast cells was analyzed by RNA dot blot hybridization. A B-cell lymphoma was negative for preproenkephalin mRNA, but several T-cell lymphomas were positive. A mastocytoma and two macrophage cell lines were found to have high levels of preproenkephalin mRNA. Purified natural macrophages and mast cells also possessed easily detectable levels of this mRNA.

Animals↗
PubMed1987

Conformation-activity relationships of opiate analgesics.

Extensive conformational calculations were performed on the potent opiate analgesics etorphine, PET, R30490 and etonitazene to determine all of their many low-energy conformations. The results were used to characterize four possible models for binding of a simple pharmacophore, comprising two phenyl rings plus a protonated nitrogen, to opiate analgesic receptors. These four models may define the necessary three-dimensional features leading to particular opiate actions. The model favoured for mu receptor activity can accommodate a protonated nitrogen, an aromatic ring (which may be substituted with an electronegative group) and a second lipophilic group. These structural features must be presented in a precise three-dimensional arrangement. It appears likely that a hydrophilic substituent in a certain region of the analgesic pharmacophore may also interact with the receptor as a secondary binding group.

Analgesics, Opioid↗
PubMed1987

[AIDS, public health and ethics: the issue of barriers].

Repeatedly, the AIDS threat has caused the emergence of proposals for obligatory, authoritarian measures. It has above all been conceived to isolate given groups, so that they be "prevented to do harm". This is done, however, against the scientific and experiential evidence which shows that such measures would be either unnecessary or ineffective. It is not in the direction of discriminations of so-called risk persons or groups that appropriate "barriers" are to be sought. What is relevant is to reevaluate positive "barriers" that each and everyone should set and manage for himself/herself, especially: interest in the other person, whom it is worth first to know well (instead of thinking right away in engaging in a mechanical and impersonal sexual relationship); reserve and courtesy; choice; respect for the other's personality and health, as well as for one's own. The reintroduction of such behaviours as preferred ways of being/living would make an effective contribution to the struggle against AIDS, contrarily to the "ghettoizing" and totalitarian temptations, which would have above all counterproductive consequences.

Acquired Immunodeficiency Syndrome↗
PubMed1987

[Follow-up of substance-dependent patients treated with methadone in the canton of Vaud (1976-1986)--preliminary results].

A survey of a methadone treated population of 562 heroin addicts was undertaken to determine which factors linked to certain characteristics of the individual or to the cures, might be associated with either a positive outcome or failure. Furthermore it enabled the recording of various modifications with regard to social and professional integration, as well as tracing the penal career, both during the cure and to the cut-off date (31 July 1986). This paper presents the preliminary results of the survey in relation, firstly, to certain aspects of the individual's career in drug abuse, within a specific population; secondly, the various efforts towards detoxification and lastly the situation with regard to their state of drug addiction at the cut-off date.

Adult↗
PubMed1987

A prospective comparative study of the extended nonstress test and the nipple stimulation contraction stress test.

The nonstress test and the nipple stimulation contraction stress test were performed at the Medical College of Georgia and the University of Mississippi Medical Center, with the use of common maternal state protocols, minimum criteria for baseline fetal heart rate reactivity, and follow-up of abnormal test results. At the Medical College of Georgia, 656 patients were studied with nonstress tests used as the primary test, whereas at the University of Mississippi Medical Center, 614 patients were managed with the nipple stimulation contraction stress test used as the primary test. Both populations were comparable in regard to pregnancy complications, gestational age, birth weight, perinatal outcomes, cesarean section rates, and the incidence of positive contraction stress tests. Specificity and positive and negative predictive values were similar for both tests. The extended nonstress test had higher sensitivity but also required significantly longer mean duration of testing. The corrected perinatal mortality rate for a reactive nonstress test or negative nipple stimulation contraction stress test was zero within one week of the last test. We conclude that both tests provide excellent primary methods of fetal surveillance and that the decision to use one test rather than the other should be made on the basis of considerations of cost, convenience, time availability, and the presence of specific test contraindications or pregnancy complications.

Breast↗
PubMed1987

Automatic external defibrillators: importance of field testing to evaluate performance.

A new automatic external defibrillator was tested first against a tape-recorded data base of rhythms and then during use by first-responding fire fighters in a tiered emergency system. The sensitivity for correctly classifying ventricular fibrillation and ventricular tachycardia was substantially less during clinical testing in 298 patients than would have been predicted from preclinical results: 52% of ventricular fibrillation analyses in patients were correctly classified versus 88% of episodes in the data base, and 22 versus 86%, respectively, for ventricular tachycardia (p less than 0.001). The detection algorithm was modified and evaluated further in another 322 patients. The modified detector performed substantially better than did the one that had been designed from prerecorded rhythms: with its use, 118 (94%) of 125 patients in ventricular fibrillation were counter-shocked compared with 91 (77%) of 118 similar patients with use of the initial algorithm (p less than 0.001). No inappropriate shocks were delivered. This improvement resulted in a shorter time to first shock (p less than 0.01) and more shocks being delivered for persistent or recurrent episodes of ventricular fibrillation (p less than 0.05). Of 620 patients treated with the automatic defibrillator, 243 (39%) had ventricular fibrillation; 57 (23%) of the 243 regained pulse and blood pressure before paramedics arrived, 141 (58%) were admitted to hospital and 71 (29%) were discharged.(ABSTRACT TRUNCATED AT 250 WORDS)

Algorithms↗
PubMed1987

Molecular structure of mammalian neuropeptide Y: analysis by molecular cloning and computer-aided comparison with crystal structure of avian homologue.

Identification and characterization of the cDNA encoding rat neuropeptide Y revealed the nucleotide sequence coding for a 98-amino acid precursor. The deduced amino acid sequence for rat neuropeptide Y is identical to the human peptide and is highly homologous to avian pancreatic polypeptide. The tertiary structure of avian pancreatic polypeptide has been previously derived from crystallographic data by Blundell and coworkers. The homology between neuropeptide Y and avian pancreatic polypeptide preserves all of the residues essential for the maintenance of the tertiary structure. Thus, it has been possible to compute a three-dimensional model of the mammalian neuropeptide, neuropeptide Y, based on the known structure of the avian homologue. This model suggest that neuropeptide preserves a compact tertiary structure characterized by extensive hydrophobic interactions between an N-terminal polyproline-II-like helix and a C-terminal alpha-helix. The model has been used to identify amino acids residing in key positions within this structure and, thereby, to direct future analysis of neuropeptide Y structure-function relationships.

Amino Acid Sequence↗
PubMed1987

Venous plasma (total) bupivacaine concentrations following lower abdominal field block.

Following local anaesthesia of the lower abdominal wall, in patients undergoing laparoscopic sterilization (n = 16), using 0.5% plain bupivacaine 40 ml (n = 8), or 0.5% bupivacaine with 1:200000 adrenaline (n = 8), venous plasma (total) bupivacaine concentrations were measured (gas-liquid chromatography) at intervals up to 2 h after the local anaesthetic was injected. Mean peak plasma venous concentration achieved following 0.5% plain bupivacaine was 2.23 +/- 0.24 micrograms ml-1 (mean +/- SEM), while the mean peak concentration following 0.5% bupivacaine with adrenaline was 0.98 +/- 0.10 micrograms ml-1 (mean +/- SEM). At all sampling times up to and including 45 min after the injection of local anaesthetic, the plasma concentrations were significantly less in the bupivacaine with adrenaline group when compared with the group in whom a plain solution was used.

Abdominal Muscles↗
PubMed1987

High local carcinogenic activity of 1,3-dimethyl-3-phenyl-1-nitrosourea and its inactivation by intravenous application in rats: comparison of in vivo findings with the in vitro direct and a combined in vivo/in vitro sister chromatid exchange assay in V79-E cells.

1,3-Dimethyl-3-phenyl-1-nitrosourea (DMPNU) is a very potent local carcinogen in rats and induces a 100% frequency of forestomach carcinomas when applied i.g. in two different dosages (10 applications of 0.3 or 0.03 mmol/kg body wt, respectively, at 14-day intervals), but it is inactive upon i.v. administration (10 applications of 0.03 mmol/kg body wt at 14-day intervals). By means of the direct sister chromatid exchange (SCE) assay in V79-E cells in the presence of rat blood, serum or plasma, respectively, as well as by a 'host-mediated' SCE assay (in which the agent was given i.v. to rats, and blood taken from the animal was checked for the recovery of genotoxic activity in cell cultures), we tried to elucidate the unexpected lack of carcinogenic activity of i.v. DMPNU. The direct SCE assay revealed a drastic reduction of DMPNU genotoxicity by rat blood, serum or plasma, respectively, which is abolished by the esterase inhibitor diisopropylfluorophosphate. In the 'host-mediated' SCE assay a genotoxic activity of DMPNU was only recoverable after a very high i.v. dose and when the blood added to the cell cultures had been taken from the rat heart within 1 min after DMPNU administration in vivo. 1-Methyl-1-nitrosourea (MNU) and 1-methyl-3-phenyl-1-nitrosourea (MPNU) were used as positive controls in these experiments and also gave a lower response than theoretically expected, but the relative loss of activity with the latter compounds was much lower than with DMPNU. It is assumed that an esterase in rat blood effectively decomposes this trisubstituted nitrosourea. Problems of the novel 'host-mediated' SCE assay are discussed.

Animals↗
PubMed1987

A new familial 'giant platelet syndrome' with structural, metabolic and functional abnormalities of platelets due to a primary megakaryocyte defect.

We have investigated platelet morphology, function and biochemistry in a family affected by dominantly inherited congenital thrombocytopenia with giant platelets. A defect of aggregation was defined with evidence of disturbed fatty acid distribution in platelet membrane phospholipids and impaired arachidonic acid mobilization. Release of 5-hydroxytryptamine was normal. Platelet ultrastructure was grossly abnormal and volume analysis revealed small as well as giant forms. Bone marrow megakaryocytes were morphologically abnormal and the distribution of mean nuclear ploidy atypical, suggesting the production of abnormal platelets due to a primary megakaryocyte disorder. The features of this condition are distinct from those previously described in familial thrombocytopenia and constitute a new "giant platelet syndrome". The qualitative and quantitative platelet defects may be secondary to a disturbance of megakaryocyte cytoplasmic fragmentation.

Adult↗
PubMed1987

School health promotion: child nutrition programs.

Since 1946, with the enactment of the National School Lunch Act, an important and integral part of the comprehensive school health program has been ensuring the nutritional needs of students are met. This article describes the history of the school nutrition program and how it has adapted to meet the needs of today's students. The modern menu is more healthful, foods are prepared with less salt, sugar, and fat, and nutrition education complements food choices. Through collaboration, nutrition education has been integrated into health education and the other elements of the total school health program to better meet students needs.

Child↗
PubMed1987

Acute lymphoblastic leukaemia: trimethoprim resistant organisms during treatment.

A cross sectional study was carried out in children receiving treatment for acute lymphoblastic leukaemia to determine the prevalence of trimethoprim resistant organisms in their gut flora and to compare this with a control population. There was a significantly higher prevalence of trimethoprim resistant bacteria in the study group (61%) compared with controls (14%). A longitudinal study showed that emergence of these organisms was intermittent during treatment.

Child↗
PubMed1987

Mortality due to respiratory cancers in the coke oven plants of the Lorraine coalmining industry (Houillères du Bassin de Lorraine).

The main activity of the Houillères du Bassin de Lorraine (Lorraine Collieries), employing 23,000 operatives and executives, is coalmining. The coke production is carried out by two coke oven plants with a workforce of respectively 747 and 552 workers. The coal coking process entails the emission of noxious products such as polycyclic aromatic hydrocarbons (PAH) from the ovens. The influence of occupational exposure on mortality due to respiratory cancers, and particularly to lung and upper respiratory and alimentary tracts cancer, was investigated among a cohort of 534 male workers from the two coke oven plants who had retired from work between 1963 and 1982. The job history of each subject has been precisely reconstructed by indicating the duration of exposure on the ovens, close to the ovens, and in maintenance occupations. The cohort mortality has been analysed according to the method of indirect standardisation with reference to the French male population and by a case-control study concerning the consumption of tobacco per cohort. The mortality due to lung cancer is 2.51 times higher than expected. This excess of mortality differs, but not significantly, between the two coke oven plants (standardised mortality ratio equals 3.05 and 1.75 respectively). It is not significantly higher among subjects exposed for more than five years, directly exposed on the ovens or working near the ovens or at maintenance occupations on the ovens (SMR = 2.78), than among those exposed for less than five years (SMR = 2.35) or those not exposed at all. Even taking into account the excess of mortality due to lung cancers in the Moselle district (1.6 time that of France), the excess of lung cancers does not seem to be explained by the regional factor, or by tobacco and alcohol consumption. Although no significant relation was offered between lung cancer and the duration of exposure to PAH, even when taking smoking habits into account, the carcinogenic role of occupational nuisances cannot be excluded.

Age Factors↗