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Biomedical subjects

C Martin

Publications and source records attributed to C Martin.

At least 937 records · Page 52Linked to original sources
PubMed1987

Abnormalities of some phagocyte membrane receptors during nosocomial infections.

The frequent and severe nosocomial infections in ICU patients suggest that these patients are immunodeficient. We studied the phagocytic activity of granulocytes and monocytes isolated from the blood of 32 ICU patients with nosocomial pneumonia (19 male, 13 female; age 41 +/- 4 yr). Cells were tested in standard medium and in the presence of patients' serum. Blood granulocytes and monocytes were purified and separately exposed to opsonized zymosan (to test C3 receptor function), immunoglobulin-coated erythrocytes (to test Fc receptor function), and glutaraldehyde-treated erythrocytes (to test nonspecific binding structures). Phagocytosis and superoxide anion production were measured. Granulocytes of patients exhibited a substantial decrease of zymosan ingestion (p less than .05), whereas phagocytosis of other particles was normal. Monocytes from the patients displayed an unselective overall decrease of phagocytic ability for the three particle types (p less than .05). Patients' sera were at least as efficient as a pool of normal sera in opsonizing zymosan. Further, no phagocytic inhibitor was found in the tested patients. In conclusion, we point out a deficiency of membrane receptors of neutrophils and monocytes in ICU patients with nosocomial infection.

Adult↗
PubMed1987

Alpha 2-adrenergic regulation of arylalkylamine N-acetyltransferase in organ-cultured chick pineal gland: characterization with agonists and modulation of experimentally stimulated enzyme activity.

In the chicken pineal gland, norepinephrine, released at sympathetic nerve endings, plays a role in synchronizing the circadian rhythm of melatonin synthesis. This effect appears to be exerted via an adrenergic inhibition of arylalkylamine N-acetyltransferase, the melatonin rhythm-generating enzyme. The present study indicates that the nighttime peak of N-acetyltransferase activity developed by organ-cultured chick pineal glands is inhibited by adrenergic agonists with a potency order characterizing alpha 2-adrenergic receptors: UK 14,304 greater than clonidine greater than alpha-methylnorepinephrine = epinephrine greater than cirazoline greater than phenylephrine greater than isoproterenol. The mechanism of this alpha 2-adrenergic response was further analyzed in organ cultures, by studying the ability of clonidine to block the cyclic AMP-dependent and the depolarization-dependent stimulations of N-acetyltransferase activity. Clonidine prevented the rise in N-acetyltransferase activity evoked by the adenylate cyclase activators forskolin and cholera toxin or by the phosphodiesterase inhibitor Ro 20,1724. The stimulatory effect of dibutyryl cyclic AMP was also blocked by clonidine. Activation of pineal alpha 2-adrenergic receptors effectively prevented the stimulation of N-acetyltransferase by depolarizing concentrations of KCl. The possibility that the alpha 2-adrenergic effect might be exerted at a step distal to cyclic AMP production is discussed.

4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinone↗
PubMed1987

Structure and mobilization of an ampicillin and gentamicin resistance determinant.

A DNA segment originally found in an epidemic plasmid of Escherichia coli encoding an aminoglycoside-(3)-N-acetyltransferase gene (aacC5) and a TEM-type beta-lactamase gene was characterized. The two genes were adjacent and constituted a single transcriptional unit. In addition, these genes were simultaneously mobilized through the action of an insertion sequence related to IS26, IS140, and IS15-delta. This DNA segment is a composite transposon which has been called Tn2922.

Ampicillin↗
PubMed1987

Meniscal tears: pathologic correlation with MR imaging.

Menisci from 12 autopsies and above-knee amputations were imaged with magnetic resonance (MR) at 1.5 T and then sectioned for gross and histologic examination. A histologic staging system was developed and showed a one-to-one correlation with corresponding grades of MR signal intensities. Histologic stages 1 and 2 represented a continuum of degeneration culminating in stage 3 fibrocartilaginous tears, seen most frequently in posterior-horn segments of the medial meniscus. Correlation of histologic stages with MR signal intensity allows for an improved diagnostic reading of MR images.

Aged↗
PubMed1987

Detection and quantitation of constriction of the fetal ductus arteriosus by Doppler echocardiography.

Pulmonary hypertension may occur in the fetus in the presence of constriction of the ductus arteriosus. The feasibility of detection and quantitation of fetal ductal constriction by Doppler echocardiography was assessed in an animal preparation in which ductal constriction was created in the fetal lamb with a variable ligature causing varying degrees of fetal pulmonary hypertension (fetal pulmonary arterial systolic pressure 57 to 97 mm Hg and ductal gradient 9 to 42 mm Hg). Comparison of blinded, continuous-wave peak Doppler velocity (V) measurements of the ductal gradient with the modified Bernoulli assumption (gradient = 4V2) compared well with direct catheter measurements of instantaneous peak systolic gradient (r = .99, catheter = 0.95 X Doppler + 0.6), peak-to-peak gradient (r = .97), and mid-diastolic gradient (r = .85). Ductal constriction was characterized by an increase in the peak systolic and diastolic velocities. The normal human fetal ductus arteriosus blood flow velocity pattern was assessed by pulsed Doppler techniques in 25 normal human fetuses after 20 weeks gestation. The peak systolic flow velocity in the ductus arteriosus measured by image-directed pulsed Doppler echocardiography ranged from 50 to 141 cm/sec (mean 80 cm/sec) and increased with gestational age (r = .50). Diastolic velocity in the ductus arteriosus was consistently directed toward the descending aorta and ranged from 6 to 30 cm/sec. The ductal systolic velocities were the highest blood flow velocities in the fetal cardiovascular system. Application of these techniques to fetuses whose mothers were receiving indomethacin for treatment of premature labor at 30 to 31 weeks gestation confirmed this method to be sensitive for detection of fetal ductal constriction, which developed in three fetuses.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Cyclothymic disorder and bromocriptine: predisposing factors for postpartum mania?

Women are most susceptible to psychotic reactions during the postpartum period, a time of intense psychological and physiological stress. Mania and depression are particularly common at this time, especially in women with past or family histories of major or minor affective disorders, specifically cyclothymia and dysthymia. Close attention after childbirth is warranted to alleviate and prevent these episodes in such women. Sympathomimetic drugs such as bromocriptine and the over-the-counter diet aids, which are linked to the induction of manic episodes, are frequently used in the puerperal period and may act as catalysts. This case report documents a postpartum manic episode in a cyclothymic woman who was prescribed bromocriptine, a dopamine agonist, for prevention of lactation.

Adult↗
PubMed1987

Right ventricular function during positive end-expiratory pressure. Thermodilution evaluation and clinical application.

Right ventricular (RV) function was studied in 13 patients under controlled mechanical ventilation with positive end-expiratory pressure (PEEP) for adult respiratory distress syndrome. The assessment of RV function was made by the thermodilution technique. Calculations of RV ejection fraction (RVEF) and RV end-diastolic volume (RVEDV) were performed. In 11 patients, increasing PEEP was accompanied by a progressive decrease in blood pressure (BP), stroke volume (SV), RVEDV, and no change in RVEF. Increasing PEEP further was accompanied by a further decrease in RV preload. The remaining two patients exhibited a decrease in BP, SV, RVEF and an increase in RVEDV. One of these two patients exhibited a large decrease in cardiac output (CO). Thus, measurement of RVEDV (best parameter of ventricular preload) and RVEF are easily performed at the patient's bedside using a special thermodilution technique. This allows selection of the best treatment of PEEP-induced decrease in CO.

Adult↗
PubMed1987

Types of male drinkers: a multivariate study.

Data from 1070 recent male drinkers were analyzed using factor analysis (as a form of data reduction) and cluster analysis to identify groups of different types of drinkers. The data were derived from a sample of 3600 face-to-face interviews conducted in the early part of 1982 in six provincial cities in New Zealand. Of this total, 1509 interviews were with male respondents, of whom 28% were either abstainers or were not recent drinkers (i.e., had not consumed alcohol in the 7 days preceding the interview). The variables that were factor analyzed included attitudinal, motivational, situational and consumption items. The resulting factor scores were submitted for clustering and the final cluster solutions were cross-tabulated by alcohol consumption measures and demographic characteristics. Six segments were identified and appeared to be primarily distinguishable on the basis of common drinking situations: Light Drinkers (43%), Frequent Early Evening Drinkers (28%), Heavy Hotel-Tavern Drinkers (21%), Club Drinkers (4%), Solitary Drinkers (2%) and Party Drinkers (2%).

Adolescent↗
PubMed1987

[Locoregional anesthesia by peri-dural route in neck surgery].

Principal anatomical "targets" and physiological consequences of cervical epidural anesthesia are outlined, technic and aims of the method discussed and 53 patients (class ASA I and II) receiving major cervical surgery, mainly for cancer, reviewed. Effectiveness of cervical epidural anesthesia was rated as excellent for total pharyngo-laryngectomy, with or without flaps, total laryngectomy, lymph node curettage and thyroidectomy, moderate for reconstructive laryngectomy and only fair for transmaxillary buccopharyngectomy. Advantages of the method concern principally the postoperative period: immediate awakening (92% of cases) in the operating room whatever the duration of surgery, avoiding intensive care, and pain relief for at least 48 hours (85% of cases) by maintenance of catheter. Contraindications include hypocoagulability, local or general infection and impossibility of adjusting heart rate, and the method is not applicable for all patients in whom general anesthesia with assisted ventilation is contraindicated.

Adult↗
PubMed1987

[Severe laryngeal dysplasia and synthetic retinoids].

Nine patients with "severe" laryngeal dysplasia as shown by multiple microbiopsies during laryngoscopy were treated with a synthetic derivative of retinol (Etretinate 0.5 to 1 mg/kg/day) over one or two months. Follow up histology after 8 to 18 months surveillance showed histologic improvement with respect to dyskeratosis, atypical cells and to a lesser extent epithelial hyperplasia. The use of synthetic vitamin A derivatives for "severe" laryngeal dysplasia is discussed.

Adult↗
PubMed1987

Determination of steady state and nonsteady-state glycerol kinetics in humans using deuterium-labeled tracer.

Using deuterium-labeled glycerol as tracer and gas-liquid chromatography-mass spectrometry techniques for the determination of isotopic enrichment, we have developed a simple and ethically acceptable method of determining glycerol appearance rate in humans under steady-state and nonsteady-state conditions. In normal subjects, the appearance rate of glycerol in the post-absorptive state was 2.22 +/- 0.20 mumol X kg-1 X min-1, a value in agreement with those reported in studies with radioactively labeled tracers. The ratio nonesterified fatty acid (NEFA) appearance rate/glycerol appearance rate ranged from 1.95 to 3.40. In insulin-dependent diabetic patients with a mild degree of metabolic control, the appearance rate of glycerol was 2.48 +/- 0.29 mumol X kg-1 X min-1. The volume of distribution of glycerol, determined by the bolus injection technique, was (mean) 0.306 l X kg-1 in normal subjects and 0.308 l X kg-1 in insulin-independent diabetic patients. To evaluate the usefulness of the method for determination of glycerol kinetics in nonsteady-state conditions, we infused six normal subjects with natural glycerol and calculated the isotopically determined glycerol appearance rate using a single compartment model (volume of distribution 0.31 l X kg-1). During these tests, the expected glycerol appearance rates were successively 5.03 +/- 0.33, 7.48 +/- 0.39, 9.94 +/- 0.34, 7.48 +/- 0.39, and 5.03 +/- 0.33 mumol +/- kg-1 X min-1, whereas the corresponding isotopically determined appearance rates were 4.62 +/- 0.45, 6.95 +/- 0.56, 10.85 +/- 0.51, 7.35 +/- 0.34, and 5.28 +/- 0.12 mumol X kg-1 X min-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗