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Biomedical subjects

R Marin

Publications and source records attributed to R Marin.

At least 55 records · Page 3Linked to original sources
PubMed1995

Extensor digitorum brevis reflex in normals and patients with radiculopathies.

This prospective study evaluated the extensor digitorum brevis deep tendon reflex (EDBR) in a normal population and in patients with L-5 and S-1 radiculopathies. There were 88 subjects: 53 normals, 17 L-5, and 18 S-1 radiculopathy subjects. The clinical EDBR revealed a 91% specificity, with 18% sensitivity for L-5, and 11% for S-1. The electrodiagnostic EDBR yielded increased sensitivities of 35% for L-5 (P = 0.07) and 39% for S-1 (P = 0.04), with 87% specificity. H-reflexes showed 50% sensitivity for the S-1 group (P = 0.0006) and 91% specificity. EDBR latencies were significantly related to age and leg length (r2 = 0.46, P < 0.0001). Age alone explained 26% (P < 0.0001) of the EDBR variability and leg length 20% (P < 0.0001). EDBR clinical and electrodiagnostic reflexes have low sensitivities, high specificities, and do not discriminate L-5 from S-1 root involvement.

Adult↗
PubMed1995

Insulin action and glucose metabolism are improved by gemfibrozil treatment in hypertriglyceridemic patients.

The aim of this study was to determine whether gemfibrozil-mediated decrease in very low density lipoprotein triglyceride (VLDL-TG) concentration is accompanied by an improvement in overall glucose metabolism in hypertriglyceridemic patients. We assessed this hypothesis in 7 hypertriglyceridemic without (HTG) and in 11 hypertriglyceridemic with noninsulin-dependent diabetes mellitus (NIDDM-HTG) who followed three-months treatment either with the drug or with placebo. Placebo VLDL-TG concentrations in both HTG (3.82 +/- 0.92 mmol/l (mean +/- S.D.) vs. 3.91 +/- 1.01 mmol/l) and in NIDDM-HTG (6.62 +/- 3.93 mmol/l vs. 6.84 +/- 4.16 mmol/l) were not different from baseline values, whereas gemfibrozil decreased VLDL-TG in both groups (1.84 +/- 0.56 mmol/l, P < 0.001 for HTG, and 1.93 +/- 2.68 mmol/l, P = 0.013 in NIDDM-HTG). In both groups, gemfibrozil treatment was associated with an improvement in fasting plasma glucose levels (from 5.85 +/- 0.92 mmol/l to 4.87 +/- 0.40 mmol/l in HTG, P = 0.001, and from 11.47 +/- 2.92 mmol/l to 9.56 +/- 3.41 mmol/l in NIDDM-HTG, P = 0.042). In NIDDM-HTG, gemfibrozil treatment was associated with a significantly lower 2 h-postprandial plasma glucose level (9.87 +/- 3.63 vs. 13.09 +/- 3.62, P = 0.05). A significant decrease in fasting free fatty acids (FFA) level was observed during gemfibrozil treatment in both groups, whereas in NIDDM-HTG, a significant drop of these substrates was observed in both fasting and postprandial conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Glucose↗
PubMed1995

Hybrid vigour against parasites in interspecific crosses between two mice species.

The resistance and susceptibility to the intestinal pinworm Aspiculuris tetraptera, a natural parasite of the house mouse Mus musculus, is experimentally analysed using both the F1 from wild-type mice of the two subspecies (M. m. domesticus and M. m. musculus) and the F1 from different laboratory inbred mice. The results show that: (i) the F1 from wild-type mice harbour a lower parasite load than the parental mice, suggesting a phenomenon of hybrid vigour; and (ii) the F1 from inbred mice harbour parasite loads similar to the resistant parent, suggesting that resistance is inherited as a dominant feature in these laboratory mice. This analysis supports the hypothesis that recombinations occurring between the two mouse genomes (i.e. M. m. domesticus and M. m. musculus) are responsible for the hybrid dysgenesis observed in the natural hybrid zone between the two mice subspecies.

Animals↗
PubMed1993

Molecular identification of onchocerciasis vector sibling species in black flies (Diptera: Simuliidae).

A number of sibling species in the Simulium damnosum species complex transmit River Blindness (onchocerciasis) in tropical Africa. Black fly sibling species can be reliably recognized only through analysis of the larval polytene chromosomes. The routine, unambiguous assignment of the potentially disease-transmitting adult females to a particular species is virtually impossible. Two molecular assays to identify the sibling species of biting female flies are presented. The first relies on PCR-mediated amplification of internal transcribed spacers of the nuclear rDNA loci while the second involves immunoblotting of silk proteins which are expressed in both larvae and adult females. Both assays yield sibling-specific size markers that can be used to identify the sibling species of biting adult females. To illustrate the use of these assays, a molecular characterization is given for two S. damnosum siblings (squamosum, sirbanum) collected from cytologically verified populations, and a partial characterization of a third sibling (damnosum s. str.) found as a contaminant in these samples.

Animals↗
PubMed1993

hsp23 and hsp26 exhibit distinct spatial and temporal patterns of constitutive expression in Drosophila adults.

To determine differences in the patterns of expression of Drosophila small heat shock proteins (shsp) during normal development in the absence of stress, proteins obtained from head, thorax and gonads of young (0-12 h, 3 days), middle-aged (3-6 days) and 15- to 20-day-old adult flies were separated on SDS-PAGE gels and blotted with monoclonal antibodies against hsp23 and hsp26. hsp23 was found in the heads and gonads of young males and females. In contrast, the maximum expression of hsp26 was seen in gonads of young flies, and it was only lightly detected in the brain. The expression of both proteins decreased as flies aged. This age-related decrease was particularly striking for hsp23 in females. The immunoblot results obtained were complemented by immunostaining of thin parasagittal sections of whole fly bodies. Hsp23 was found to be expressed in the brain, thoracic ganglion, fat body and gonads of young (0-12 h) males and females. On the other hand, hsp26 was essentially detected in ovaries and testes of these young flies. The analysis of the tissue expression of both proteins demonstrate that each shsp has a distinct cellular localization. In the central nervous system, hsp23 and hsp26 were present in the neurocytes of the brain and the thoracic ganglion. In addition, hsp23 (but not hsp26) was also detected in the central neuropile of these two organs. In testis, hsp26 was localized in the cytoplasm of spermatocytes and, probably, in the spermatid bundles. In contrast, hsp23 was detected at the periphery of cells (membranes).(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1993

Lipoprotein compositional abnormalities in type 1 (insulin-dependent) diabetic patients.

Patients with type 1 (insulin-dependent) diabetes mellitus in good metabolic control usually have normal plasma lipid levels yet they have an increased incidence of vascular complications. Abnormalities in the distribution and composition of lipoprotein subfractions might in part be responsible for the macroangiopathy seen in type 1 diabetes mellitus. The plasma lipids, lipoproteins and apolipoproteins were studied in 9 type 1 diabetic patients during conventional insulin therapy and in 14 healthy controls. Plasma lipoproteins were analysed by ultracentrifugation in a zonal rotor to evaluate their concentrations and flotation properties and for compositional analysis. In diabetic patients the mean glycosylated haemoglobin (HbA1c) was 9.44 +/- 1.02% and the plasma lipid concentrations were not significantly different from healthy controls. The very low density lipoprotein (VLDL) subclass cholesterol concentrations were no different in diabetic patients and control subjects, but the VLDL cholesterol/triglyceride ratio was significantly lower in diabetic patients than in control subjects (0.43 +/- 0.05 vs 0.85 +/- 0.14; p < 0.05). The flotation rate LDL2, the major component of low density lipoprotein (LDL) was lower in the diabetic patients compared with the control subjects. The cholesterol concentrations of intermediate density lipoprotein and LDL3, the minor component of LDL, were significantly higher (0.17 +/- 0.03 and 0.83 +/- 0.14 mmol/l respectively) in diabetic patients than in control subjects (0.05 +/- 0.02 and 0.24 +/- 0.08 mmol/l). The flotation properties and cholesterol concentrations of the high density lipoprotein (HDL) subclass, and the protein-lipid composition of LDL2, HDL2 and HDL3, were no different in diabetic patients and control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Design and integration of a graphic interface for an expert system in oncology.

We describe a graphic user interface for an expert system in oncology. The main objectives of our work has been to facilitate the adaptation of the system to different clinical environments and potentiate the factors which more directly determine the acceptance of the system by its users. We present the design principles derived from the features of the clinical domain chosen and from the objectives of the system. These principles are reflected on the design of the screen and of the interaction and in the style of integration of the interface with the other components of the system. Underlying the application we describe is a graphic user interface management system which provides facilities for the fast prototyping and integration of interfaces. We describe here those features of this tool which make the practical application of the design principles we consider possible.

Clinical Protocols↗
PubMed1992

Isolation and sequence of a 2-kbp miniplasmid from Bacillus thuringiensis var. kurstaki HD-3a3b: relationship with miniplasmids of other B. thuringiensis strains.

The miniplasmid profiles of 18 Bacillus thuringiensis strains belonging to 8 different serotypes were determined using an alkaline hydrolysis method for isolation of low molecular mass plasmids. Nearly all the strains contained covalently closed circular (CCC) DNA species ranging from 2 to 5 species per strain and from 1.5 to 10.5 kbp in size (values corresponding to CCC forms). A 2-kbp plasmid from B. thuringiensis var. kurstaki HD-3a3b futura strain was used in Southern hybridization experiments to analyse relationships among the low molecular mass plasmids of different B. thuringiensis strains. This 2-kbp miniplasmid was present in most strains which show toxicity against lepidoptera. It was not present in those strains toxic against diptera (B. thuringiensis var. israelensis) or coleoptera (B. thuringiensis var. tenebrionis). The 2-kbp miniplasmid from B. thuringiensis var. kurstaki HD-3a3b futura was cloned and fully sequenced. Sequence analysis of the 2058 bp of the miniplasmid revealed the presence of an ORF (630 bp, 210 amino acids in size) that is preceded by a consensus sequence of B. thuringiensis crystal protein gene transcription promoters. No significant homology was observed with known B. thuringiensis toxin nucleic acid sequences or with other known sequences.

Amino Acid Sequence↗
PubMed1992

Twenty-four hour blood pressure monitoring in the Syst-Eur trial.

This article describes the objectives and protocol of a study on ambulatory blood pressure in elderly patients with isolated systolic hypertension. This study constitutes an optional side-project to the Syst-Eur trial. The multicentre Syst-Eur trial investigates whether antihypertensive treatment of elderly patients with isolated systolic hypertension will influence the incidence of stroke. Secondary endpoints include cardiovascular events, such as myocardial infarction. The main objective of the side-project is to investigate whether ambulatory blood pressure monitoring will improve the prediction of cardiovascular complications based on blood pressure measurement in the clinic. The side-project also provides the opportunity to evaluate the diurnal profile of blood pressure in elderly patients with isolated systolic hypertension randomized to placebo or active antihypertensive treatment.

Aged↗
PubMed1992

Transcription patterns of human papillomavirus type 16 in genital intraepithelial neoplasia: evidence for promoter usage within the E7 open reading frame during epithelial differentiation.

Human papillomavirus (HPV) type 16 transcription was analysed by in situ hybridization using 125I-labelled subgenomic riboprobes, from 26 genital intraepithelial neoplastic (IN) lesions, in formalin-fixed biopsies from 18 different cases. Distinct transcription patterns separable by the presence or absence of late gene transcription were detected. In 12 lesions, late gene expression was absent; HPV transcripts corresponding to the E6 and E7 open reading frame (ORF) were detectable in all basal cells and were usually evenly distributed through all layers of the epithelium. Transcripts corresponding to the E1, E2 and E2/E4 ORFs were present in nine of 12 lesions and displayed a similar distribution. In 14 lesions late gene transcripts were present. E6 and E7 transcripts were detectable basally in all but one lesion. The levels of E7 but not E6 transcripts were markedly increased in the superficial cells of differentiating epithelia, with an identical distribution and at similar levels to those of the E2/E4 transcript. We propose that the most abundant transcript in genital IN lesions containing late gene expression is an E7/E1 [symbol: see text] E2/E4 transcript corresponding to that reported in HPV-6/11 condylomata and which is derived from a similar promoter within the E7 ORF.

Cell Transformation, Neoplastic↗
PubMed1992

Ambulatory blood pressure monitoring in elderly patients with isolated systolic hypertension.

OBJECTIVES: This study compared clinic and ambulatory blood pressure measurement and the reproducibility of these measurements in older patients with isolated systolic hypertension (ISH). PATIENTS: Eighty-seven patients aged greater than or equal to 60 years with ISH on clinic measurement were followed in the placebo run-in phase of the Syst-Eur trial. METHODS: Clinic blood pressure was defined as the mean of two blood pressure readings on each of three clinic visits (six readings in total). Ambulatory blood pressure was measured over 24 h using non-invasive ambulatory blood pressure monitors. RESULTS: Daytime ambulatory systolic pressure was, on average, 21 mmHg lower than the clinic blood pressure, whereas diastolic pressure was, on average, similar with both techniques of measurement. In the 42 patients who had repeat measurements, clinic blood pressure levels nad the amplitude of the diurnal blood pressure profile (fitted by Fourier analysis) were equally reproducible. However, both were less reproducible than ambulatory blood pressure levels. The repeatability coefficients, expressed as per cent of near maximum variation (four times the standard deviation of a given measurement), were 52% and 45% for the clinic systolic and diastolic pressures, 56% and 42% for the amplitude of the diurnal profile, and 29% and 26% for mean 24-h pressures. CONCLUSIONS: In older patients with ISH, clinic and ambulatory systolic blood pressure measurements may differ largely: the prognostic significance of this difference remains to be elucidated. Furthermore, in these patients the level of pressure is more reproducible by daytime ambulatory blood pressure measurement than by clinic measurement.

Aged↗
PubMed1992

Isokinetic exercise system modification for short below-the-knee residual limbs.

The use of isokinetic exercise has been shown to be an effective way of strengthening debilitated muscles. In the below the knee amputee, significant quadriceps and hamstring muscle wasting has been documented. Although isokinetic strengthening of the debilitated knee extensors and flexors in the below the knee amputee would be beneficial, there are no fully described isokinetic equipment modifications in literature that would allow a short below the knee amputee to effectively use isokinetic equipment. This article describes such a modification.

Adult↗
PubMed1991

A comparison of nizatidine and ranitidine in the maintenance treatment of duodenal ulcer. A randomized, double blind, multicentre, 2-year study.

UNLABELLED: One hundred and eight patients with an endoscopically documented healed duodenal ulcer (DU) participated to a multicentre, randomized, double-blind, long-term study. The study was planned with the aim to compare the efficacy of nizatidine 150 mg with ranitidine 150 mg in preventing relapse during the 2 years following the DU healing. Fifty four patients were assigned to each treatment. Endoscopic examinations were scheduled at 6, 12 and 24 months. Clinical evaluations were performed every two months. Routine laboratory tests were investigated at the beginning of the study and at each of the scheduled endoscopies. STATISTICS: chi-squared test with Yate's correction, Student's t test for unpaired data, Wilcoxon Rank Sum test and Logrank test. Twenty five patients dropped-out: 15 in the nizatidine and 10 in the ranitidine group. The cumulative relapse rate was 18% for nizatidine and 21% for ranitidine treatment (p:ns). Both drugs resulted safe, as only minor side effects were registered. IN CONCLUSION: nizatidine is as effective and safe as ranitidine in the long-term (2 year) treatment of DU.

Adult↗
PubMed1991

Neuropathological effects and deaths of cattle and sheep in Argentina from Phalaris angusta.

Neuropathological disorders and mortality occurred in cattle and sheep grazing P angusta. This native plant of South America is frequently found as a good quality component of natural pastures. Cattle and sheep feeding in pastures where P angusta was dominant started dying or showing signs 3 to 5 d after rain-falls started following a period of drought. Some animals died suddenly, while others nervous effects( incoordination, inability to walk normal, recumbency) and death for up to 2 w after the beginning of the signs. Postmortem findings were bilaterally symmetrical, greenish pigmented areas in the grey matter of the brain stem and diencephalon. A greenish tinge was also noted between the cortex and the medulla of the kidneys. Granules of a brown pigment were noted within the cytoplasm of neurons. An alkaloid substance was detected in the plant. Morbidity was 2.3 to 10.5% in herds B and A, and 0 to 3.4% in flocks D and C, respectively. Mortality was 0.8 to 1.0% in herds B and C, and 3.4 to 11.7% in flocks D and C, respectively. P angusta behaves, in terms of toxicity, as other Phalaris spp. Its widespread distribution in areas of extensive grazing poses a threat to cattle and sheep production in Argentina.

Alkaloids↗
PubMed1989

The effect of cell K+ on the volume regulation in rat kidney cortex cells.

Incubation of outermost rat kidney cortex slices (rich in proximal tubules) at 0 degrees C in a medium without K+ produces an increase in their cell water, Na+ and Cl- contents and a diminution in their cell K+ content. When these slices are rewarmed at 25 degrees C in a medium without K+, they can regulate their cell volume and their cell Na+ and Cl- contents. When the rewarming period lasts more than 30 min, there is again a cellular swelling, which seems to be correlated with the diminution of the cell K+ concentration. This effect of cellular K+ appears to be related to severe changes in cellular permeability to ions and water. The oxygen consumption and the cell ATP concentrations are similar to those in control conditions. The ouabain-insensitive Na-pump activity is not affected by different concentrations of K+.

Animals↗