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Biomedical subjects

C Martin

Publications and source records attributed to C Martin.

At least 955 records · Page 53Linked to original sources
PubMed1987

[Reconstructive laryngectomies. Technical and functional aspects].

Technical aspects are described of the reconstructive laryngectomy used between 1982 and 1986 to treat 59 patients with endolaryngeal epidermoid carcinoma. Both "conservative" techniques (Tücker's laryngectomy, total endolaryngeal functional evidement) and "non-conservative" techniques (cricohyoidopexy, cricohyoidoepiglottopexy, cricobasiglossopexy) as well as their functional outcome are described. Results of surgical review of endolaryngeal spaces (paraglottic space, hyothyroepiglottic space) are analyzed for each method, and a schema for their use proposed.

Adult↗
PubMed1986

Repetitive axonal discharges elicited by serotonin and intracellular adenosine 3',5'-cyclic monophosphate in the crayfish neuromuscular junction.

Experiments were carried out in the opener muscle of the claw of small crayfish. After pretreatment of the preparation with serotonin (5-HT), application of the membrane permeant analogue of adenosine 3',5'-cyclic monophosphate (cAMP), 8-bromoadenosine 3',5'-monophosphate was capable of evoking reversibly repetitive discharges in the inhibitory and excitatory axon. Reducing phosphodiesterase activity with application of either 3-isobutyl-1-methylxanthine or theophylline also elicited repetitive axonal discharges after 5-HT treatment. Moreover, application of forskolin dissolved in ethanol caused repetitive axonal discharges. The chemically induced presynaptic action potentials were detected mainly by their postsynaptic effects, i.e. by recording inhibitory and excitatory postsynaptic currents in voltage-clamped muscle fibres. In addition, nerve spikes were recorded extracellularly. It is concluded that 5-HT and intraaxonal cAMP alter membrane properties of the efferent axons innervating crayfish muscle.

1-Methyl-3-isobutylxanthine↗
PubMed1986

Pharmacokinetics of methotrexate and its 7-OH metabolite in cancer patients treated with different high-methotrexate dosage regimens.

The pharmacokinetics of methotrexate (MX) and 7-OH methotrexate (MXOH) was studied in 18 cancer patients treated with 6-hr intravenous (i.v.) infusion of 100 mg/kg (A), 80 mg/kg preceded by 20 mg/kg i.v. loading dose (B), and 70 mg/kg preceded by 30 mg/kg i.v. loading dose (C). Simultaneous analysis of MX and MXOH was performed by high-performance liquid chromatography. The data for MX conformed to a 2-compartment model with overall mean +/- SD for beta, k12, k21, and k13 of 0.225 +/- 0.196, 1.33 +/- 1.44, 0.954 +/- 1.06, and 0.994 +/- 1.28 hr-1, respectively. The total body clearance, Vc, and V-beta were 0.123 +/- 0.037 l/hr.kg, 0.15 +/- 0.122 l/kg, and 0.965 +/- 0.875 l/kg, respectively. No significant differences (p greater than 0.05) in these parameters, attributable to the difference in regimens, were observed. With regimens A, B and C, the maximum observed concentrations of MXOH occurred at 9.2, 11.5, and 9.2 hr and the mean +/- SD values of these concentrations were 15.02 +/- 14, 18.96 +/- 13.63, 14.91 +/- 9.95 microM, respectively. With regimens A and C, maximum observed concentrations of MX equal to 231 +/- 67.1 and 204 +/- 69.5 microM occurred at 0.5 and 6 hr, respectively. Only with regimen B was a steady-state MX concentration of 179 microM achieved throughout infusion; this regimen is therefore highly advantageous for high-dose MX treatment.

Adolescent↗
PubMed1986

[3 cases of neonatal cyto-steatonecrosis. Physiopathological discussion].

Three cases of subcutaneous fat necrosis of the newborn (SFNN) are presented. They occurred after a therapeutic coma induced by intravenous barbiturates to control convulsions unresponsive to conventional treatment. Two patients had widespread lesions. Histopathology showed prominent vascular involvement. Since 1970, 26 cases of SFNN have been published. Among the aetiological factors already described, hypothermia and ischaemia play a major role. It is suggested that brown adipose tissue might be of importance in the pathophysiology of subdural fat necrosis of the newborn.

Adipose Tissue, Brown↗
PubMed1986

Transposable elements generate novel spatial patterns of gene expression in Antirrhinum majus.

The pallida gene of A. majus encodes a product required for the synthesis of red flower pigment. We have shown that the unstable pallida(recurrens) mutation is due to the insertion of the Tam3 transposable element near the promoter of the gene. Imprecise excision of Tam3 alters pallida gene expression and generates new spatial patterns or different intensities of flower pigmentation. Distinct spatial patterns may also result from rearrangements induced by Tam3 that alter the relative position of the pallida gene. Changes in Tam3 structure or position result in new unstable phenotypes. These findings suggest that genes may be rendered genetically hypervariable as a consequence of transposable element insertion and excision.

Alleles↗
PubMed1986

Heterologous expression and regulation of the lysA genes of Pseudomonas aeruginosa and Escherichia coli.

The Pseudomonas aeruginosa lysA gene encoding diaminopimelate decarboxylase (DAP-decarboxylase) was cloned into a broad host range vector. This gene complemented a lys mutation at the lys-12 locus of P. aeruginosa and a lysA defect in Escherichia coli. The P. aeruginosa DAP-decarboxylase was synthesized constitutively in P. aeruginosa as well as in E. coli, where the Pseudomonas lysA gene was poorly expressed. By contrast, the E. coli lysA gene was expressed well in P. aeruginosa and subject to lysine regulation when the E. coli LysR activator protein was provided. This indicates that the mechanism of transcriptional activation for the E. coli lysA gene is effective in the heterologous host.

Bacterial Proteins↗
PubMed1986

Spontaneous excitatory postsynaptic currents in crayfish neuromuscular junctions in the absence and presence of serotonin and 3,4-diaminopyridine.

Spontaneous excitatory postsynaptic currents (sEPSCs) were recorded under voltage clamp in short fibres (l less than or equal to 0.6 mm) from opener muscles and the contractor epimeralis muscle of small crayfish. From the amplitude distributions of sEPSCs which could be approximated by a Gaussian function, a mean amplitude ã = -1.16 nA +/- 0.28 (SE) was found for sEPSCs in 16 fibres of the claw opener voltage clamped to E = -60 mV (19-22 degrees C). In the opener of the first walking leg and in the contractor epimeralis muscle ã = -1.1 nA +/- 0.21 (SE; n = 6, -100 mV less than or equal to E less than or equal to -60 mV, 5-10 degrees C) and ã = -2.0 nA +/- 0.2 (SE; n = 4, E = -60 mV, 19-22 degrees C) were obtained. On average about 300-500 synaptic channels were estimated to open during a sEPSC. 'Giant' sEPSCs (gsEPSCs) were also observed. The amplitudes of gsEPSCs were up to 14 times larger than the amplitude of an average normal sEPSC. Moreover, the lifetime of gsEPSCs was up to about 3 times longer than that of sEPSCs. Like sEPSCs, gsEPSCs could not be abolished by 0.1 mumol/l tetrodotoxin. The rate at which sEPSCs and gsEPSCs occurred could be markedly enhanced by serotonin (1 mumol/l) and 3,4-diaminopyridine (1 mmol/l).

4-Aminopyridine↗
PubMed1986

Hospitalization on the high-risk maternity unit. A pilot study.

Women hospitalized for high-risk pregnancy appear to be at high risk for adverse reactions to hospitalization. Nine pregnant women remaining in hospital for 1 week or more were studied prospectively with a semistructured questionnaire, standard self-administered measures, and staff rating. Six women presented serious problems of compliance or psychic functioning. Women who suffered these adverse reactions tended to be poor, unemployed, younger, less educated, Catholic, unmarried, and to have children at home, when compared to the three women not experiencing difficulty. Women subsequently manifesting problems were significantly likelier on admission to appear as "cases" on the SCL-90-R and to have higher scores on the POMS. On the basis of pilot results, hospitalization for high-risk pregnancy appears to be a particularly stressful event. Women most at risk for problems can probably be identified prospectively.

Female↗
PubMed1986

[Assessment of ventricular function by thermodilution in controlled ventilation with positive end expiratory pressure].

Controlled mechanical ventilation with PEEP can induce important haemodynamic modifications. The aim of this study was to focus on right ventricular function, often altered with that kind of respiratory support. Bed-side assessment of right ventricular function was made possible through thermodilution technique. Eleven patients receiving PEEP from 0 to 15 cmH2O were studied. Right ventricular end-diastolic volume (RVEDV), cardiac output (CO) and right ventricular ejection fraction (RVEF) were obtained for each patient. Increasing PEEP produced the same disturbances in nine patients, i.e. decreased RVEF. Blood volume expansion brought back to normal the haemodynamic values. Two patients had a decrease in CO and RVEF associated with an increase in RVEDV. In one of these two patients, dobutamine corrected the RV dysfunction. Using thermodilution technique, abnormalities of RV preload can be accurately assessed. From these data, the most appropriate treatment can then be chosen.

Adult↗
PubMed1986

[Pulmonary artery catheterization by the percutaneous approach to the axillary vein].

The choice of venous access can be difficult in patients under intensive care. The axillary vein appeared interesting to evaluate. This prospective study involved 63 punctures carried out in 59 patients during a 16 month period (14 females and 45 males; mean age: 54 +/- 4 yr). 34 patients were tracheostomized and under controlled respiration; some had coagulation abnormalities (8 cases). The other 29 patients were undergoing a preoperative haemodynamic study. Puncture of the axillary vein was carried out with the needle inserted at an angle of 30 degrees to the skin surface and directed parallel to the artery medial to its course. The Seldinger technique was used (catheter and guide wire). Overall success rate was 87.5%. In 73%, less than three attempts were required. After the catheter was set in place in the axillary vein, the mean time required to reach the pulmonary artery was 7 +/- 15 min (range: 20 s-45 min). Less than 1 min was needed in 60%. Extrasystoles were observed in 3.6%. The incidence of arterial puncture was 11% without any late complications. In every case, pulmonary artery and capillary wedge pressure curves were obtained, as well as cardiac output measurements. Mean duration of catheterization was 2 +/- 1.1 days in the preoperative haemodynamic group and 4 +/- 1.7 days in the other. No infectious complication was related to the catheterization. One thrombosis of the axillary and subclavian veins was noted (1.8%). The axillary vein appeared therefore to be useful for pulmonary artery catheterization. It is an alternative choice in patients under controlled ventilation and with coagulation problems.

Adult↗
PubMed1986

Response of spontaneously hypertensive rats to 1,25(OH)2D3 in vivo.

Calcium absorption in spontaneously hypertensive rats (SHR) has been reported to be increased, decreased or not different from their normotensive Wistar Kyoto (WKy) control. One postulated reason for these conflicting results is an abnormal sensitivity to the intestinal effects of 1,25(OH)2D3 (1,25D3). Previous studies in everted duodenal sacs and perfused duodenum examined the acute response to 1,25D3 only in 12-week-old SHR, which however already had higher basal rates of calcium absorption. Inability to stimulate Ca absorption further was an unexcluded possibility. To test this hypothesis more vigorously, balance and in situ duodenal 45Ca uptake studies were performed in SHR and WKy using four separate protocols yielding the following results. First, in response to pharmacological doses of 1,25D3 (25 ng/100 g body wt/day X 3), four-week-old normotensive female SHR had higher net calcium absorption (41.4 vs. 31.1 mg/day; 61.6 vs. 48.1%), similar to the increases seen in the untreated state. These results suggest intrinsic epithelial differences independent of 1,25D3. Ca absorption was similarly higher in 1,25D3 treated male SHR (42.9 vs. 36.7 mg/day; 60.1 vs. 53.7%). Second, at 12 to 14 weeks of age, low doses of 1,25D3 (8 ng/100 g body wt/day X 6) stimulated net Ca absorption in the female SHR (33.0 to 39.1 mg/day), but not in WKy (26.8 to 29.3 mg/day). In the male, positive effects were again seen only in the SHR (25 to 45 mg/day). Third, in response to three weeks of dietary Ca deprivation, in situ duodenal 45Ca uptake, measured in the conscious awake state, was higher in 35-week-old SHR (70.9 vs. 53.0%).(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1986

Aminoglycoside-phosphotransferases APH(3')-IV and APH(3") synthesized by a strain of Campylobacter coli.

Campylobacter coli strain 981 of animal origin was resistant to erythromycin, tetracycline, streptomycin, kanamycin, ribostamycin, neomycin, paromomycin, lividomycin, and butirosin. Resistance to aminoglycosides of strain 981 was mediated by phosphotransferases APH (3') type-IV and APH (3"). C. coli 981 harboured three plasmids of 24, 34, and 40 Megadaltons respectively. None of these plasmids were transferable to Escherichia coli K-12 by conjugation.

Aminoglycosides↗
PubMed1986

K-Nutrition, Growth Bud Formation, and Amine and Hydroxycinnamic Acid Amide Contents in Leaf Explants of Nicotiana tabacum Variety Xanthi n.c. Cultivated in Vitro.

The effects of K-nutrition on growth (increase of fresh weight), bud formation (time of emergence, number of buds), and amine and hydroxycinnamic acid amide contents in foliar explants of Nicotiana tabacum cv Xanthi n.c. cultivated in vitro were examined. In K-deficient medium and in high K medium growth and bud formation were markedly inhibited. Marked changes of amine content (a diamine, putrescine; a phenolic amine, phenethylamine) were observed after a few days of culture. No apparent relationship was found between these amines and growth or bud differentiation. In contrast, changes in hydroxycinnamic acid levels were shown to correlate well with growth and bud formation. The greatest stimulation of budding and growth was correlated with the greatest accumulation of these amides. The highest contents of hydroxycinnamic acid amides were found during the first 15 days in culture when intensive cell division took place. Then they declined sharply after 26 days in culture as the rate of cell division decreased and differentiation occurred.

Journal Article↗
PubMed1986

Tertatolol does not affect biochemical markers of atherosclerosis in normo- and hyperlipidemic hypertensive patients.

The effects of the beta-blocker tertatolol on plasma lipids and lipoproteins were studied in two groups of 10 normolipidemic (group I) and 10 hyperlipidemic (group II) hypertensive patients, for a period of 3 months. The efficacy of tertatolol was confirmed by a reduction in heart rate (HR), and in systolic (SBP) and diastolic (DBP) blood pressure, in the supine position and after 1 min in the upright position. Triglyceride (TG) levels were increased by treatment in both groups (+20% and +22%, respectively; p less than 0.05), as were VLDL levels (+16% and +24%, respectively) although the rise in the latter was not significant. There were no significant differences in levels of HDL cholesterol (HDL-C), HDL, or apoproteins A and A1 (APO A, APO A1). Total cholesterol (TC) levels were increased by treatment in group I (+10%; p = 0.050) and decreased in group II (-9%, not significant), LDL-C being the principal fraction involved in these changes. There were no significant differences in levels of APO B. The ratio between TC and HDL-C levels remained unchanged. Given the current state of our knowledge concerning lipid markers for atherosclerosis, these results indicate that chronic administration of tertatolol may be considered devoid of 'atherogenic' effects.

Adrenergic beta-Antagonists↗