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Biomedical subjects

M Martin

Publications and source records attributed to M Martin.

At least 631 records · Page 35Linked to original sources
PubMed1991

Safety of triple lumen catheters in the critically ill.

The authors performed this prospective study to determine the infection rate of triple lumen catheters (TLC) in their surgical intensive care unit (SICU) patient population. Patients who required a central venous line for the first time while in their SICU were studied. Those with preexisting catheter infections, bacteremias, and TLC reinsertions were excluded. TLC was placed through the internal jugular or the subclavian vein and all peripheral lines were removed. The distal port was used for parenteral nutrition and the other two ports were used for fluids and medications. Dressings were changed daily and blood cultures were obtained through each port of the TLC. At the time of catheter removal, blood, catheter tip, and the subcutaneous tract were cultured. Duration of catheterization was recorded. Eighty-six catheters were studied. The mean duration of catheterization was 6.2 days and the range was two to 23 days. Six of 86 (6.9%) catheter tip cultures were positive and the remaining 80 (93.1%) were negative. Two positive tips (2.3%) had negative blood cultures for two catheter infections (CIs). The remaining four catheters (4.6%) had associated bacteremias for four catheter sepsis (CS). The two catheter infections occurred among catheters indwelling for 10 days or less while the four cases of catheter sepsis occurred among catheters indwelling longer than 10 days. In conclusion, triple lumen catheters can be safely left in place for up to 10 days with minimal risk for bacteremia.

Bacterial Infections↗
PubMed1991

The utility of cardiac evaluation in the hemodynamically stable patient with suspected myocardial contusion.

Myocardial contusion following isolated blunt thoracic trauma (BTT) remains a diagnostic and therapeutic dilemma. To identify the presence of cardiac abnormality following BTT, 123 hemodynamically stable patients were prospectively evaluated with serial electrocardiograms (ECG) and cardiac enzymes (total CPK and CPK-MB). Gated cardiac radionuclide angiography (MUGA) scans were performed within 48 hours following admission. Patients included in the study sustained significant thoracic trauma identified by physical findings or mechanism of injury. Sixty-three patients (51%) were identified with either abnormal ECG, or abnormal total CPK, CPK-MB, MUGA scan, or combination of the above. Thirty-seven patients (58.7%) manifested an ECG abnormality defined as ST-segment or T-wave abnormality. Twenty-two patients (34.9%) had total CPK value greater than or equal to 50 International Units (I.U.) or CPK-MB fractions greater than or equal to five per cent. MUGA scan was abnormal (right ventricular ejection fraction less than 40 per cent and/or wall motion abnormality) in 12 patients (19%). Eight patients with MUGA scan abnormality had normal ECG and/or normal total CPK, CPK-MB values. Evaluation of all patients up to six months revealed no mortality, malignant arrhythmias, or cardiac failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Management options in fulminant hepatic failure.

The diagnosis of FHF carries with it a high mortality rate. Though the early results of OLT for FHF are encouraging, some have called for caution as these results are in a select population and may be similar to the optimistic early reports of now-discredited therapies. However, OLT differs fundamentally from all other interventions and, as such, it is ethically unjustified to withhold potentially life-saving therapy from patients with a predicted mortality in excess of 60%. Therefore, patients with FHF should be transferred at an early stage to an experienced liver unit where the option of liver transplantation can be considered.

Acute Kidney Injury↗
PubMed1991

[Food restraint and acute stress in women].

According to restraint theory, people scoring high in this dimension of eating behavior should exhibit a conflict between biological set point and cultural norm. In order to explore the hypothesis that this tension should lead to heightened vulnerability to stress, 17 healthy women between 18 and 54 years of age, previously studied from the point of view of eating behavior, were submitted to a five-minute stressful challenge (public speaking). Visual analogue anxiety scales and plasma free fatty acids indicated that high restraint scores predict heightened reactivity to this stressor in women. Such result helps to differentiate further psychological factors related to disorders of eating.

Acute Disease↗
PubMed1990

Grasp the moment.

Explore the source record for details and available documents.

Community Participation↗
PubMed1990

Hot water temperature in Dunedin homes with preschool children.

The mean temperature of the hot water supply of 62 randomly selected Dunedin homes with preschool children was 67.8 degrees C. More than 95% of the households visited had temperatures above the recommended temperature of 55 degrees C. The temperature was related to the socioeconomic status of the major earner of the household, the thermostat setting, the age of the water cylinder and its size. Accessible thermostats were of the water cylinder and its size. Accessible thermostats were only reliable in cylinders under 20 years old.

Burns↗
PubMed1990

Targeting of indium 111-labeled bivalent hapten to human melanoma mediated by bispecific monoclonal antibody conjugates: imaging of tumors hosted in nude mice.

Antibody conjugates were prepared by coupling F(ab')2 or Fab' fragments of an antibody specific for the human high molecular weight-melanoma associated antigen to Fab' fragments of an antibody specific for indium-diethylenetriaminepentaacetate complexes. Monovalent and bivalent haptens were synthesized by reacting the dipeptide tyrosyl-lysine with diethylenetriaminepentaacetic cyclic anhydride. In vitro, the antibody conjugate mediated binding of the 111In-labeled haptens to melanoma cells. In vivo, it allowed specific localization of the haptens in A375 tumors. The bivalent hapten exhibited much higher efficiency at targeting 111In onto cells, both in vitro and in vivo. Antibody conjugate and hapten doses (2 micrograms and 1 pmol, respectively) and the delay between antibody conjugate and tracer injections (24 h) were adjusted to maximize tumor uptake (4% injected dose/g) and tumor to normal tissue contrast (greater than 3) obtained 3 h after injection of the 111In-labeled bivalent hapten. This two-step technique, when compared to direct targeting of 111In-labeled F(ab')2 fragments, provided lower localization of injected activity into the tumor (x 0.25), but higher tumor/tissue ratios, especially with respect to liver (x 7), spleen (x 8), and kidneys (x 10). In addition, high contrast images were obtained within 3 hours, instead of days. Thus, antibody conjugate-mediated targeting of small bivalent haptens, labeled with short half-life isotopes, is proposed as a general method for improving tumor radioimmunolocalization.

Animals↗
PubMed1990

The relationships between the cortisol responses to dexamethasone and to L-5-HTP, and the availability of L-tryptophan in depressed females.

In order to investigate the relationships between the hypothalamic-pituitary-adrenal (HPA)-axis activity, the central serotonergic neurotransmission, and the peripheral metabolism of l-tryptophan (L-TRP), the authors measured the following: the postdexamethasone cortisol values, the cortisol responses to 125 mg 5-hydroxy-L-tryptophan (L-5-HTP) orally, and the total L-TRP/competing amino acids (CAA) ratio in 64 depressed females. Severely depressed females showed significantly lower values for L-TRP/CAA, significantly higher postdexamethasone cortisol values, and cortisol responses to L-5-HTP as compared with minor depressives. Dexamethasone nonsuppressors showed significantly lower L-TRP/CAA values as compared with suppressors. The cortisol responses to dexamethasone were significantly and negatively correlated with the availability of L-TRP. The cortisol responses to L-5-HTP were not related to either the availability of L-TRP or to the postdexamethasone cortisol values.

5-Hydroxytryptophan↗
PubMed1990

Failure of ceftibuten to alter single dose theophylline clearance.

Twelve volunteers participated in a two-way crossover trial in which the effects of ceftibuten on the pharmacokinetics of theophylline were evaluated. Subjects were given single intravenous doses of theophylline (4 mg/kg) with no ceftibuten treatment and on the sixth day of ceftibuten treatment. Ceftibuten 200 mg was taken orally twice daily (7:00 AM and 7:00 PM). A total of 13 blood samples per subject were collected over 48 hours following theophylline administration. Ceftibuten failed to alter either the systemic clearance of theophylline (CL), its volume of distribution (Vss), or its elimination half-life (t1/2). The 24-hour plasma theophylline concentration measured both by high performance liquid chromatography (HPLC) or fluorescence polarization immunoassay (FPIA) was used for a single sample estimate of theophylline clearance (CL), and it was found to provide a suitable estimate of the multisample value for CL.

Administration, Oral↗
PubMed1990

Changes in the steady-state pharmacokinetics of theophylline during treatment with dirithromycin.

The steady-state plasma concentrations and pharmacokinetic characteristics of theophylline were studied during intermittent treatment with dirithromycin. The addition of dirithromycin (500 mg orally once daily at 7:00 AM) to a sustained-release theophylline dosing regimen (200 mg every 12 hours) elicited small changes in the steady-state pharmacokinetics of theophylline. Mean steady-state plasma theophylline trough concentrations (Cmin) were invariant before, during, and after dirithromycin treatment; however, mean average steady-state plasma theophylline concentrations (Cav) declined by 18% during dirithromycin treatment (P less than .05), and mean peak plasma concentrations (Css,max) declined by 26% (P less than .01). Theophylline clearance (CL/F) exhibited an increase of comparable magnitude during dirithromycin treatment, although the increase in CL/F was not statistically significant (.05 less than P less than .1). Dirithromycin treatment alters the steady-state pharmacokinetics of theophylline; however, the magnitude of the changes is small and is not likely to modify treatment outcomes.

Administration, Oral↗
PubMed1990

Modifications of microfilaments and microtubules induced by two hepatic tumor promoters, phenobarbital and biliverdin in non-transformed and transformed hepatic cell lines.

Microfilaments and microtubules are components of the cytoskeleton which could be implicated in neoplastic transformation. We studied the effect of two hepatic tumor promoters, phenobarbital (PB) and biliverdin (BV), on microfilaments and microtubules of non-transformed (Cl3) and transformed (FV) hepatic epithelial cells. Cl3 non-transformed cells cultured in the presence of 1 X 10(-6) M BV for 48 h showed a loss of F-actin, fragmentation of actin and the appearance of star-like structures in the cytoplasm, as well as loosening of the peripheral bundle of actin, and some ruffling of cell membranes. In Cl3 cells exposed to 0.2 X 10(-3) M PB a similar disappearance of F-actin staining and a very prominent ruffling of cell membrane were observed. BV and PB also produced in these cells modifications of microtubules characterized by a disappearance of centrosome staining in numerous cells, a condensed ring of tubulin around the nucleus and a depolymerized aspect of the microtubular network. All these modifications of microfilaments and microtubules closely resembled those observed in FV transformed cells in the absence of any treatment (Solvent DMSO only). We did not observe an effect of BV and PB on FV cells. The present data demonstrate that the cytoskeleton of non-transformed epithelial liver cells is sensitive to the action of liver tumor promoters suggesting that it might play a role as to yet be defined in the promotion mechanism.

Actin Cytoskeleton↗
PubMed1990

Fibronectin and collagen gene expression during in vitro ageing of pig skin fibroblasts.

The fibronectin, collagen type I, and collagen type III genes code for three major proteins of the cell matrix. The age-related alterations in their expression were measured during the in vitro lifespan of pig skin fibroblasts. We observed changes in the transcription rate of these specific genes during ageing. The levels of fibronectin and type III collagen mRNA rose markedly during the senescence phase. The level of collagen type I mRNA decreased during cell ageing, while that of beta-actin did not change. As regards proteins, we observed a sharp increase in the secreted noncollagenous proteins and in the total proteins of the cell layer during senescence. On the contrary, the secretion of the collagenous proteins decreased during senescence. Moreover, most of the newly synthesized molecules of collagen were immediately degraded in the cells, before their extracellular secretion. The terminal phenotype of pig senescent cells was therefore characterized by overexpression of fibronectin and type III collagen genes and reduced expression of the type I collagen gene. Surprisingly, for fibronectin and type III collagen, that terminal phenotype resembled the one normally found in the fibroblasts during the processes of tissue repair, cicatrization, and development.

Aging↗
PubMed1990

Neuropeptides from the sinus gland of the lobster Homarus americanus: Characterization of hyperglycemic peptides.

In order to characterize hyperglycemic peptides from the sinus gland of the lobster, Homarus americanus, a bioassay was developed with juvenile H. gammarus. This assay was used for determining the hyperglycemic activity of peptides perified by reversed-phase high-performance liquid-chromatography, from acidic extracts of sinus gland. The major peptides are eluted in three sets of two peptides. Among them, two pairs show hyperglycemic activity when assayed on lobster; when assayed on crayfish, three peptides are active. The less hydrophobic pair consists of basic peptides (pI: 8.7), with a MW of 8633 Da., determined by fast-atom bombardment mass spectrometry. The most hydrophobic pair consists of acid peptides (pI: 5.0), with a MW of 8577 Da. Amino acid composition of the hyperglycemic peptides shows strong homologies within each pair.

Amino Acids↗
PubMed1990

Congenital cerebellar hypoplasia and hypogonadotropic hypogonadism.

The association of cerebellar ataxia and non-neurological syndromes is a well known phenomenon. A 20-year-old male patient presented with a longstanding and non-progressive ataxia. Magnetic resonance examination revealed marked inferior vermian-cerebellar hypoplasia. He also showed a hypogonadism with low serum gonadotropin and prolactin levels. Chronic pulsatile gonadotropin-releasing hormone (GnRH) administration resulted in a small non-pulsatile luteinizing hormone (LH) increase and no follicle-stimulating hormone (FSH) elevation. This hormonal pattern suggests a primary deficiency of the gonadotroph and lactotroph cells, rather than a hypothalamic lesion. This is the first report where cerebellar hypoplasia of congenital origin is associated with hypogonadotropic hypogonadism. Because of consanguinity, autosomal recessive transmission is considered.

Adult↗
PubMed1990

Suppressive effects of dexamethasone on hypothalamic-pituitary-thyroid axis function in depressed patients.

This study investigated the effects of dexamethasone (1 mg orally) on the function of the hypothalamic-pituitary-thyroid (HPT) axis. We determined pre- and post-dexamethasone thyroid-secreting hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), reverse T3 and cortisol levels in 61 depressed inpatients. Dexamethasone had a pronounced suppressive effect on basal TSH and FT3 levels. It had a significant stimulating effect on rT3 levels. No differences were found between melancholic and minor depressives in the effects of dexamethasone on basal TSH, FT3 and rT3. Cortisol non-suppressors were characterized by less suppression of basal TSH values.

Depressive Disorder↗