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Biomedical subjects

C Martin

Publications and source records attributed to C Martin.

At least 775 records · Page 43Linked to original sources
PubMed1990

Renal effects of norepinephrine used to treat septic shock patients.

Twenty-four patients with septic shock (cardiac index [CI] greater than or equal to 4 L.min-1.m-2, systemic vascular resistance index [SVRI] less than or equal to 350 dyne.sec.cm-5.m-2, systolic BP less than or equal to 90 mm Hg, oliguria less than 30 ml/h) were treated with norepinephrine (NE) infused either alone or in combination with dopamine and/or dobutamine. In all patients, NE resulted in either an increase in BP, no change, or an increase in CI and restored SVRI to the normal range. In 20 patients, normalization of systemic hemodynamics was followed by re-establishment of urine flow, decrease in serum creatinine, and increase in creatinine clearance. None of these 20 patients received low dose dopamine or furosemide. Four patients remained oliguric. Two of these four patients died and two developed acute renal failure. These findings suggest that NE infusion does not worsen renal ischemia related to hemodynamic disturbances in septic shock patients, and may have beneficial effects on renal function.

Adult↗
PubMed1990

Assessment of creatinine clearance in intensive care patients.

Assessment of creatinine clearance (CC) in ICU patients was compared using three methods. The reference method (CC 24 h) used measurements of serum creatinine and urinary creatinine after collection of urine over a 24-h period. The other two methods were predictive methods: the Kampmann nomogram and the formula developed by Gault and Cockcroft. The two predictive methods correlated well with one another. Correlation between the predictive and the reference methods was poor or absent. A discriminant analysis revealed that measurement of urinary creatinine was a major factor in CC estimation. In conclusion, the reference method of CC assessment is preferred to obtain a reliable estimation of glomerular filtration rate in ICU patients.

Adolescent↗
PubMed1990

Results of a locking-hook spinal rod for fractures of the thoracic and lumbar spine.

The results of a consecutive series of 110 patients treated with the locking-hook spinal rod are presented. A prospective protocol was completed in 95 patients. Pain was absent or mild in 93%. In those patients with a partial neurologic deficit, there was recovery of at least one Frankel grade in 84%. The overall kyphotic deformity was reduced from 21 to 17 degrees. In those patients in whom no anterior surgery was performed, the deformity improved from 21 to 13 degrees. No rod fractures occurred, and the overall instrument complication rate was 13.7%, of which one was due to infection and four secondary to uncrimped nuts, for a true complication rate of 8.4%. The locking-hook spinal rod has proven to be a satisfactory internal fixation device in the treatment of unstable thoracolumbar fractures.

Adult↗
PubMed1990

Inverse Relationship between Polyamine Levels and the Degree of Phenotypic Alteration Induced by the Root-Inducing, Left-Hand Transferred DNA from Agrobacterium rhizogenes.

Floral induction in plants is a paradigm for signal perception, transduction, and physiological response. The introduction of root-inducing, left-hand transferred DNA (Ri T-DNA) into the genomes of several plants results in modifications of flowering (D Tepfer [1984] Cell 47: 959-967), including a delay in flowering in tobacco (Nicotiana tabacum). Conjugated polyamines are markers for flowering in numerous species of plants. In tobacco their accumulation is correlated with the onset of flowering (F Cabanne et al. [1981] Physiol Plant 53: 399-404). Using tobacco, we have explored the possibility of a correlation between the expression of Ri TL-DNA and changes in polyamine metabolism. We made use of two levels of phenotypic change, designated T and T', that retard flowering by 5 to 10 and 15 to 20 days, respectively. We show that delay in flowering is correlated with a reduction in polyamine accumulation and with a delay in appearance of conjugated polyamines, and we propose that genes carried by the Ri TL-DNA intervene either directly in polyamine metabolism or that polyamine metabolism is closely linked to direct effects of Ri T-DNA expression.

Journal Article↗
PubMed1990

The interaction of phenytoin and carbamazepine with combined oral contraceptive steroids.

Patients taking oral contraceptive steroids (OCS) are known to suffer contraceptive failure while taking anticonvulsants such as phenobarbitone, phenytoin and carbamazepine. We have studied the single dose kinetics of ethinyloestradiol (EE2); 50 micrograms, and levonorgestrel (Ng); 250 micrograms in groups of women before and 8-12 weeks after starting therapy with phenytoin (n = 6) and carbamazepine (n = 4). The area under the plasma concentration-time curve (AUC) was measured over a 24 h period for each steroid and significant reductions were seen with both anticonvulsants. Phenytoin reduced the AUC for EE2 from 806 +/- 50 (mean +/- s.d.) to 411 +/- 132 pg ml-1 h (P less than 0.05) and for Ng from 33.6 +/- 7.8 to 19.5 +/- 3.8 ng ml-1 h (P less than 0.05). Carbamazepine reduced the AUC for EE2 from 1163 +/- 466 to 672 +/- 211 pg ml-1 h (P less than 0.05) and for Ng from 22.9 +/- 9.4 to 13.8 +/- 5.8 ng ml-1 h (P less than 0.05). These changes are compatible with the known enzyme inducing effects of phenytoin and carbamazepine. Patients taking these anticonvulsants will need to be given increased doses of OCS (equivalent to 50-100 micrograms EE2 daily) to achieve adequate contraceptive effects.

Adolescent↗
PubMed1990

A lipopeptide-encoding sequence upstream from the lysA gene of Pseudomonas aeruginosa.

An open reading frame (ORF) of 141 bp was observed upstream from the Pseudomonas aeruginosa lysA gene. The translation product of this ORF contains a signal peptide with a lipoprotein box, Ile-Ala-Ala-Cys, at the predicted signal peptidase cleavage site. The Escherichia coli phoA gene without its signal sequence was fused in frame to this ORF in a broad host-range plasmid. The resulting construct expressed a hybrid protein exhibiting alkaline phosphatase activity in phoA mutants of both E. coli and P. aeruginosa. This indicates that the ORF encodes a peptide, part of which acts as an export signal. The hybrid peptide was identified by immunoblotting with alkaline phosphatase antiserum. The accumulation of a precursor form was observed when P. aeruginosa cells carrying this gene fusion on a plasmid were treated with globomycin. Moreover, the mature form could be labelled with 2-[3H]-glycerol, indicating that lipidic residues may be linked to the hybrid protein. Taken together, these results strongly suggest that the ORF encodes a lipopeptide. We propose that the gene is called IppL.

Amino Acid Sequence↗
PubMed1990

Analysis and characterization of the interleukin 2 receptor alpha and beta chain expression in CD4-CD8- cells.

The differential effects that the binding of interleukin 2 (IL-2) to its beta or alpha beta receptors might induce in two different CD4-CD8- T-cell lines were analysed. While LD1.T3b, a double-negative T cell derived from MRL/lpr mice, constitutively expressed high levels of the IL-2R beta chain, YAC-1, a Moloney sarcoma virus-transformed CD4-CD8- T cell, expressed (as an activated T cell) the beta and alpha chains. The presence of IL-2 in the culture medium was lethal for LD1.T3b cells, while it had no effect on the growth of YAC-1 cells. IL-2 increased the expression of the beta chain and, to a lesser extent, of the alpha chain in YAC-1 cells. In addition, other markers such as CD4 and CD5 were induced by IL-2 in this cell line.

CD4-Positive T-Lymphocytes↗
PubMed1990

Septic shock: a goal-directed therapy using volume loading, dobutamine and/or norepinephrine.

In patients with septic shock and acute respiratory failure, norepinephrine (NE) alone or in combination with dobutamine was used. The aim of therapy was to obtain or maintain Cl greater than or equal to 4.5 l.min-1.m-2, SVR greater than or equal to 700-800 dyn.s.cm-5 and oxygen delivery (Do2) greater than or equal to 550 ml.min-1.m-2. Twenty-three patients (58 +/- 3 years) were studied. Initially patients were given intravenous fluid resuscitation to obtain optimal cardiac filling pressures. Eleven patients were considered to be in hyperdynamic septic shock (cardiac index (CI) greater than 4.5 l.min-1.m-2, SVR less than or equal to 600 dyn.s.cm-5 and oliguria) and were given NE as a single agent (0.9 +/- 0.2 micrograms kg-1.min-1). The other 12 patients had Cl less than 3.5 l.min-1.m-2 and were given a combination of dobutamine (12 +/- 0.09 micrograms.kg-1.min-1) and NE (1.1 +/- 0.2 micrograms.kg-1.min-1). The latter drug was added since systemic vascular resistance (SVR) was less than 600 and oliguria persisted while on dobutamine. In all patients, during NE infusion SVR was greater than 700 dyn.s.cm-5, Cl greater than or equal to 4.5 l.min-1.m-2 and Do2 greater than 550 ml.min-1.m-2. Urine flow was significantly increased during NE infusion, and only four patients remained oliguric. Anion gap and oxygen consumption were not modified. A complete resolution of septic shock was seen in 16 out of 23 patients (70%). Hospital mortality was 56%.

Adult↗
PubMed1990

Pharmacokinetics and tissue penetration of a single dose of ornidazole (1,000 milligrams intravenously) for antibiotic prophylaxis in colorectal surgery.

Levels in serum and tissue penetration of ornidazole were studied after a single intravenous injection of 1,000 mg given to 14 patients for prophylaxis of surgical infection. They were scheduled for elective colorectal surgery. Adequate levels in blood (greater than or equal to MIC for 90% of Bacteroides fragilis strains tested) were found in all patients throughout the procedure and up to hour 24. Mean-maximal (15 min) and last-determined (24 h) ornidazole levels in serum were 24 +/- 5.2 and 6.3 +/- 1.4 mg/liter, respectively. beta-Phase elimination half-life was 14.1 +/- 2.7 h, and clearance and apparent volume of distribution were 47 +/- 12 ml/min and 0.9 +/- 0.13 liters/kg, respectively. In all patient, adequate levels in tissue were found in the abdominal wall and the epiploic fat at time of incision and in the colonic wall at time of anastomosis. At time of closure, all but one patient had adequate levels in tissue in the abdominal wall and the epiploic fat. No anaerobic nor aerobic infection occurred in the study patients.

Aged↗
PubMed1990

Conditional mutations occur predominantly in highly conserved residues of RNA polymerase II subunits.

Conditional mutations in the Saccharomyces cerevisiae RNA polymerase II large subunit, RPB1, were obtained by introducing a mutagenized RPB1 plasmid into yeast cells, selecting for loss of the wild-type RPB1 gene, and screening the cells for heat or cold sensitivity. Sequence analysis of 10 conditional RPB1 mutations and 10 conditional RPB2 mutations revealed that the amino acid residues altered by these distinct mutations are nearly always invariant among eucaryotic RPB1 and RPB2 homologs. These results suggest that RNA polymerase mutants might be obtained in other eucaryotic organisms by alteration of these invariant residues.

Amino Acid Sequence↗
PubMed1990

Genetic exploration of interactive domains in RNA polymerase II subunits.

The two large subunits of RNA polymerase II, RPB1 and RPB2, contain regions of extensive homology to the two large subunits of Escherichia coli RNA polymerase. These homologous regions may represent separate protein domains with unique functions. We investigated whether suppressor genetics could provide evidence for interactions between specific segments of RPB1 and RPB2 in Saccharomyces cerevisiae. A plasmid shuffle method was used to screen thoroughly for mutations in RPB2 that suppress a temperature-sensitive mutation, rpb1-1, which is located in region H of RPB1. All six RPB2 mutations that suppress rpb1-1 were clustered in region I of RPB2. The location of these mutations and the observation that they were allele specific for suppression of rpb1-1 suggests an interaction between region H of RPB1 and region I of RPB2. A similar experiment was done to isolate and map mutations in RPB1 that suppress a temperature-sensitive mutation, rpb2-2, which occurs in region I of RPB2. These suppressor mutations were not clustered in a particular region. Thus, fine structure suppressor genetics can provide evidence for interactions between specific segments of two proteins, but the results of this type of analysis can depend on the conditional mutation to be suppressed.

Alleles↗
PubMed1990

Endothelial cells inhibit the vascular response to adrenergic nerve stimulation by a receptor-mediated mechanism.

Rabbit central ear arteries, with and without endothelium, were perfused at a constant flow rate and the perfusion pressure was measured as an index of the vessel resistance. Transmural nerve stimulation (TNS) induced a frequency-dependent increase in perfusion pressure in all vessels that was blocked by tetrodotoxin, phentolamine, and prazosin. Removal of endothelium significantly enhanced contractions induced by TNS. The inhibitory effect of endothelium was not modified by indomethacin but was abolished by hemoglobin, indicating that endothelium-derived relaxant factor (EDRF) was the vasodilator involved. The endothelium-dependent inhibitory effect (rubbed vessel minus control vessel contractions) increased with time during the first 10-20 s after the beginning of TNS, and was frequency dependent and inhibited by low doses of phentolamine, which suggest a receptor-mediated mechanism. To analyze whether amine neurotransmitters are able to permeate the artery wall and contact the endothelial cell membrane, the passage of [3H]acetylcholine from the abluminal side to the lumen was studied in intact vessels. [3H]acetylcholine readily permeated the vessel wall, as assessed by radioautography, and appeared in the perfusion fluid at a concentration that explains the relaxation induced by perivascular acetylcholine. These data suggest that endothelial cells modulate the effect of perivascular neurotransmitters by a receptor-mediated mechanism. In the case of the sympathetic innervation, such modulation would be more relevant at low levels of transmitter release and would be minimized during intense sympathetic stimulation.

Acetylcholine↗
PubMed1990

Stress and puerperal psychosis.

Eighty-eight in-patients admitted to a psychiatric mother-and-baby unit and 80 randomly selected recently delivered women in the general population were interviewed using the LEDS. Only five of 33 patients (15%) with puerperal psychosis had provoking agents, which is less than the figure for women in the community (36%). Provoking agents were present in only 8 of 25 patients with post-natal depression, but they were present in seven of nine patients with pre-natal depression and eight of nine women in the community with pre-natal depression.

Adult↗
PubMed1990

Heat and moisture exchangers and vaporizing humidifiers in the intensive care unit.

A prospective, randomized, controlled study was undertaken to compare the Pall Ultipor breathing circuit filter (PUBCF), a heat-and-moisture exchanger, and heated hot water systems (HHWSs) in ICU patients submitted to controlled mechanical ventilation. Humidification of inspired gas and bacterial contamination of breathing circuits were evaluated. During the study, there were six episodes of tracheostomy tube (TT) occlusion in six patients included in the PUBCF group. No patient out of 42 included in the HHWS group experienced this complication (p less than 0.01). There were 4 percent of days with thick and tenacious bronchial secretions in the PUBCF group and no case in the HHWS group (p less than 0.02). In the PUBCF group, 23 percent of days with hypothermia were noted as opposed to 12 percent in the HHWS group (p less than 0.01). Fewer breathing circuits were found to be contaminated in the PUBCF group (11 percent) than in the HHWS group (54 percent, p less than 0.01). In patients with an organism growing in bronchial specimens, the same organism was found to contaminate the breathing circuit in 10 percent of cases in the PUBCF group and 77 percent of cases in the HHWS (p less than 0.01). We conclude that, in the conditions of this study, the PUBCF did not provide sufficient humidification of inspired gas in ICU patients. Protection against contamination of breathing circuits was effective, but 10 percent of patients remained at risk for this complication.

Adult↗
PubMed1990

Increased reduced glutathione and glutathione S-transferase activity in chronic cephaloridine nephrotoxicity studies in the rat.

The effect of repeated cephaloridine treatment on renal glutathione and related enzymes has been investigated in young adult male and female Sprague-Dawley rats. Animals were given intraperitoneally daily doses of either 750 mg/kg for two weeks or 500 or 750 mg/kg for three months. Measurement of blood and urinary parameters (electrolytes, urea, creatinine) did not reveal any renal function impairment and histological examination confirmed the absence of renal damage. By contrast, an increase in reduced glutathione (2 to 3-fold) and glutathione S-transferase activity (1.5 to 2-fold) was observed. These results are consistent with the development of an adaptative phenomenon to cephaloridine subchronic treatment in the rat, leading to a tolerance to high repeated doses.

Acetylglucosaminidase↗
PubMed1990

[Clinical and bacteriologic course of wounds as a function of various protocols of local antisepsis].

Antiseptics are drugs, and they must be prescribed by physicians. A correct use allows a favourable evolution of the wounds, and could avoid some amputations. The authors have realized a randomized study, to compare the reliability of a sequence using Eosine and an antiseptic (Chlorhexidine or polyvinylpyrolidone (PVP) iodine) to a more usual sequence using chlorhexidine of PVP iodine alone according with the initial pH of the wound. After fifteen days, if no clinical and bacteriological improvement occurred, the Dakin solution was used. The clinical and bacteriological survey has showed that the sequence with Eosine produced significantly more failures and that there was no significant difference between Chlorhexidine and PVP iodine. The use of the Dakin solution 15 days after inefficacy of the antisepsis previously used allowed a cicatrisation of the wound in about six days. There was no demonstrable resistance of microorganisms to the previously used antiseptics.

Adolescent↗