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Biomedical subjects

S Garcia

Publications and source records attributed to S Garcia.

At least 163 records · Page 9Linked to original sources
PubMed1987

Perioperative cefamandole prophylaxis against infections.

Seven hundred and seventeen patients were included in a prospective randomized double-blind trial comparing the efficacy of five doses of cefamandole (group I, 335 patients) with that of a single preoperative dose (group II, 382 patients) for prophylaxis against sepsis in patients who had an operation using either a Moore prosthesis, Ender or Küntscher nails, a bone plate, or another internal-fixation device. Patients who had an open fracture or total joint replacement were not included in the study. The two groups were similar in terms of mean age, sex ratio, duration of preoperative hospital stay, underlying risk factors, and type of surgical procedure. A wound infection developed in none of the seventy-four patients in group I and in five (6.6 per cent) of the seventy-six in group II (p = 0.03) who required a Moore prosthesis. A wound infection developed in three patients (1 per cent) in group I and in fifteen (5 per cent) in group II (p = 0.006) who required an internal fixation device other than a Moore prosthesis. Staphylococcus aureus, Staphylococcus epidermidis, and gram-negative bacilli were the most common infecting organisms. The rate of mortality was similar in both groups, while the percentage of postoperative urinary-tract infections was lower in group I (p = 0.04). No adverse side effects of the drug were encountered.

Adult↗
PubMed1986

Dopaminergic projection from nucleus raphe dorsalis to neostriatum in the rat.

The existence of a dopamine (DA) projection from nucleus raphe dorsalis (RD) to neostriatum was demonstrated in the rat by combined tyrosine hydroxylase (TH) immunohistochemistry and radioautography after retrograde axonal transport of [3H]noradrenaline ([3H]NA). Intrastriatal injections of [3H]NA were carried out in normal rats or after ipsilateral destruction of the nigrostriatal DA system by injection of 6-hydroxydopamine (6-OHDA) into the substantia nigra. Some 1,000 TH-positive nerve cell bodies were counted within the confines of RD as defined by its content in serotonin (5-HT) neurons. These DA neurons occupied the upper third of the RD and they were part of its small cell population. In all cases, a small proportion of the TH-immunoreactive nerve cell bodies in RD were retrogradely radiolabeled. Radiolabeled but immunonegative cells were exceedingly rare. The double-labeled neurons were generally more numerous after elimination of the nigrostriatal DA innervation than in normal rats. They mostly lay within the ventral portion of the medial subdivision of RD and always predominated on the [3H]NA- injected side. Some were also present in nucleus linearis caudalis. It was concluded that [3H]NA had been taken up and retrogradely transported exclusively by catecholamine neurons; part of the DA cell group in RD projects to the neostriatum; and that most if not all non-5-HT neurons projecting from RD to neostriatum are likely to be dopaminergic.

Animals↗
PubMed1986

Quantification of the dopamine innervation in adult rat neostriatum.

Conditions leading to specific and integral visualization of dopamine axon terminals (varicosities) were tested in adult rat cerebral hemisphere slices incubated with [3H]dopamine and processed for high resolution radioautography. Specific visualization of the dopamine endings was achieved after incubation with 10(-6) M [3H]dopamine in the presence of a monoamine oxidase inhibitor (pargyline 10(-4) M), and of desipramine (5 X 10(-6) M), an inhibitor of catecholamine uptake by noradrenaline and serotonin neurons. [3H]Dopamine varicosity labeling was eliminated by the addition of 5 X 10(-5) M benztropine (an inhibitor of catecholamine uptake by catecholamine neurons), and was almost absent when dopamine nerve cell bodies of the midbrain had been previously destroyed with 6-hydroxydopamine. In dopamine-denervated neostriatum incubated without desipramine, a second set of labeled terminals was also visible. These were identified as serotoninergic, since their labeling was suppressed by citalopram, an inhibitor of monoamine uptake highly specific for serotonin neurons. There was no desipramine-sensitive but citalopram-resistant varicosity labeling suggestive of neostriatal noradrenaline innervation. In normal striatum, incubation at 35 degrees C always resulted in a labeling of dopamine varicosities restricted to a narrow band which followed the contours and cut surface of this anatomical region. This unusual distribution was the result of an uptake barrier generated by the tightly packed dopamine varicosities. Indeed, the striatal dopamine varicosity labeling was more widespread after partial 6-hydroxydopamine denervation or in normal tissue incubated either with a higher [3H]dopamine concentration (5 X 10(-6) M), in the presence of relatively low benztropine concentrations (10(-5) M), or at lower temperature (15 degrees C). Material incubated at 15 degrees C for 90 min was suitable for purposes of quantification: labeled varicosities were then visualized throughout the striatum and across the full thickness of the slices; moreover, the number of labeled varicosities plotted against radioautographic exposure time increased in parallel and reached a plateau at the same time in neostriatal sectors with widely different innervation densities. At a rostral transverse level across neostriatum, the dorsolateral quadrant showed hyperdense "patches" of labeled terminals distinguishable from an already dense surrounding "matrix", whereas, ventromedially, the dopamine innervation appeared more uniform and somewhat less dense.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1985

Depression in the young unemployed and those on Youth Opportunities Schemes.

Using interviews and psychometric measures, this study compared the experiences and opinions of unemployment of four small groups of young people who were: unemployed, on a Youth Opportunities Placement Scheme, on a Youth Opportunities Project Scheme, or employed apprentices. It was found by means of the Beck Depression Inventory, that there were significant differences between the groups, with the employed being less depressed than the other three groups. The two groups on Youth Opportunities Schemes were intermediate but not significantly different from the unemployed. No significant differences were found using the Neuroticism scale of the EPI. This measure of depression, and the general attitudes expressed in discussion, support the conclusion that although the Youth Opportunities Scheme tends to reduce depression from being unemployed, it does not provide the psychological benefits of permanent employment, as suggested by previous research. This discrepancy in findings is discussed and the question raised as to whether the positive benefits of training programmes are sustained over time.

Adolescent↗
PubMed1984

Separation of macromolecular RNAs by reversed-phase high-performance liquid chromatography.

The reversed-phase high-performance liquid chromatography of synthetic and natural RNAs was studied. The results show that base composition alone cannot explain the retention characteristics of natural RNAs; secondary structures are probably involved. However, under the conditions described, the separation was independent of the sizes of the molecules. 18S and 28S ribosomal RNAs were eluted after tRNAs but before 9S globin mRNA. Furthermore, globin mRNA was resolved into two species, one containing and the other lacking poly(A). When applied to the separation of HeLa cell poly(A)-containing RNA, an heterogeneous pattern was obtained. Analysis of peptides synthesized by the mRNA showed that the separation is independent of size.

Chromatography, High Pressure Liquid↗
PubMed1983

Behaviour of macromolecular RNA in reversed-phase HPLC.

Large RNA molecules are retained on reversed-phase columns and can be eluted by increasing the concentration of acetonitrile. The retention behaviour depends on the base composition but not on the length of the chain, thereby providing a means for the separation of RNA molecules with different base composition. However, isocratic elution is not feasible due to the sudden changes in retention characteristics which are observed with slight variations in acetonitrile concentration. In order to interpret these results, a model has been developed called 'multiple-point interaction theory', based on the assumption that macromolecules are flexible and very large as compared to the hydrophobic phase. This model fits the experimental data and could be applied to all types of flexible macromolecules, especially proteins and nucleic acids, when they are chromatographed on reversed-phase columns. In the case of RNA, it has been observed that the retention time depends on ionic strength, pH, and temperature as expected for a true partition between two phases. Furthermore, an artifact called the 'polypeak phenomenon' appears at high flow rates which decreases the resolution of RNA. This polypeak phenomenon is controlled by the slope of the gradient d phi/dV.

Base Composition↗
PubMed1982

The serotonin neurons in nucleus raphe dorsalis of adult rat: a light and electron microscope radioautographic study.

The serotoninergic nerve cell body population of nucleus raphe dorsalis (RD) was identified by radioautography following cerebroventricular instillation of tritiated serotonin ([3H]5-HT) in adult rats pretreated with a monoamine oxidase inhibitor. Series of histological sections taken throughout the midbrain and upper pons exhibited a similar distribution and number of labeled nerve cell bodies in RD after prolonged administration of either 10-5 or 10-4M [3H]5-HT or 10-4M [3H]5-HT and 10-3M nonradioactive noradrenaline. This allowed systematic mapping and quantification of serotoninergic nerve cell bodies at various levels of the RD. Their extrapolated total number averaged 11,500. Twice as many unreactive (nonserotoninergic) neurons were present within the same region. In electron microscope radioautographs, the labeled cells were usually larger (17.9 micrometer mean diameter) than their unlabeled congeners (13.1 micrometer), but stereological sampling of their perikarial organelle content failed to reveal any difference in cytoplasmic composition. Few [3H]5-HT-labeled axonal varicosities were observed in RD and none were found in close apposition or in synaptic junction with labeled nerve cell bodies, dendrites, or unreactive perikarya. A detailed statistical analysis of silver grain distribution in both labeled and "unlabeled" nerve cell bodies, indicated that in the former, but not in the latter, dense bodies had a relatively high affinity for [3H]5-HT. Mitochondria and the cytoplasmic membrane were the only other organelles to show higher labeling indices in labeled than in unlabeled cells. Other sites of [3H]5-HT localization could be ascribed to artefactitious cross-linkage of the tracer by the fixative, since they had the same relative affinity in the two cell populations. These results provide new insights into the morphology and cytofunctional properties of the 5-HT neurons of rat RD.

Animals↗
PubMedDate not supplied

Thyroperoxidase immunodetection for the diagnosis of malignancy on fine-needle aspiration of thyroid nodules.

We have previously demonstrated that in 95.6% of malignant thyroid tumors the enzyme thyroid peroxidase (TPO) presents antigenic changes detectable by a monoclonal antibody termed MoAb47. The aim of this study was to investigate the interest of TPO immunodetection for the diagnosis of malignancy on fine-needle aspiration biopsy (FNAB) of thyroid nodules. The study was performed on 300 patients. Slides of FNAB aspirate were air-dried and stained by anti-TPO-MoAb47. According to the percentage of TPO-positive epithelial cells, patients were divided into two groups: benign (> 80%) and malignant (< 80%). In 279 cases additional slides were available for Giemsa stain and standard cytology. All the patients were operated on, and the final diagnosis was recorded as benign in 248 cases (183 macrofollicular nodules, 23 microfollicular adenomas, 18 atypical adenomas, 11 oncocytomas, 11 thyroiditis, 2 Graves' disease) and malignant in 52 cases (44 papillary carcinomas and 8 follicular carcinomas). Samples from 215 of 248 benign nodules yielded 80% to 100% TPO-positive cells, whereas samples from all malignant tumors yielded less than 80% positive cells. The sensitivity of TPO staining for diagnosis of malignancy was thus 100%, its specificity 86.7%, and its overall accuracy 89%. With conventional cytology, sensitivity, specificity, and accuracy were 91.6%, 79.2%, and 81.0%, respectively. We conclude from this study that TPO staining with MoAb47 should become an essential adjunct in the preoperative cytologic diagnosis of thyroid nodules.

Adenocarcinoma, Follicular↗
PubMedDate not supplied

Molecular typing of thermotolerant species of Campylobacter with ribosomal RNA gene patterns.

Ribosomal RNA gene restriction patterns (ribopatterns) of 72 strains representing Campylobacter jejuni (subspecies jejuni and doylei), C. coli, C. upsaliensis and C. lari including the urealytic (UPTC) biovar were determined using four common restriction endonucleases (HaeIII, HindIII, PstI and PvuII). The relative effectiveness of these enzymes for general molecular typing of the thermotolerant campylobacters was assessed. Ribotypes (HaeIII) were defined on the basis of computer-assisted numerical analysis. For C. jejuni, C. coli and C. lari, the HaeIII ribopatterns provided a high level of typability and discrimination, with patterns that were reproducible and easy to code for numerical analysis. There was evidence of diversity within three of the HaeIII types, and PstI ribopatterns proved the most reliable for detecting such differences. C. upsaliensis also could be ribotyped with HaeIII, but HindIII, PvuII and PstI were less satisfactory for this species. For such campylobacters, the HindIII ribopatterns generally were complex and difficult to compare, and the PvuII profiles provided the least discrimination. We conclude that the choice of restriction endonuclease is of critical importance when applying ribotyping to different species of Campylobacter. HaeIII ribopatterns were the most effective means of typing strains of different thermotolerant species of campylobacters and, when combined with PstI ribopatterns, offered a highly discriminatory basis for molecular typing.

Bacterial Typing Techniques↗
PubMedDate not supplied

Low probability of transmission of Trypanosoma cruzi to humans by domiciliary Triatoma sordida in Bolivia.

The role of Triatoma sordida in the domestic transmission of Trypanosoma cruzi was assessed in 7 rural localities in Velasco Province, Department of Santa Cruz, Bolivia. Tri. sordida, the only triatomine species identified in these localities, was found inside 58.0% of houses but not in large numbers (3.1 bugs per infested house on average). A total of 220 faecal samples from domiciliary bugs was examined microscopically and by the polymerase chain reaction for the presence of trypanosomes: 21.4% were infected. Analysis of blood meals of domiciliary Tri. sordida showed that humans were the commonest host (70.4%), followed by chickens and dogs. Four of 418 persons tested were seropositive for Tryp. cruzi. Only 2 of a second group of 62 persons living in dwellings infested by Tri. sordida were seropositive. Tryp. cruzi infection was demonstrated in dogs and domestic rats. Three other species of small mammals were found to be infected with trypanosomes. In our study area, domestic Tri. sordida are mainly incriminated in the transmission of Tryp. cruzi to synanthropic animals, whereas transmission to humans is very rare. The presence in houses of small populations of Tri. sordida infected with Tryp. cruzi is therefore currently insufficient for this insect to constitute a major epidemiological risk factor.

Animals↗
PubMedDate not supplied

[Priapism].

Priapism has been defined by AFUD as a pathological condition which consists in a penile erection that persists moreover or is not related to sexual stimulation. Priapism pathophysiology has remained unknown until differents groups of clinical investigators began to research about this entity in patients complaining of erectile dysfunction, who where receiving treatment with intracavernosal vasoactive molecules. Priapism can be clasified into ischaemic (venocclusive): the most prevalent type, or Arterial (non-ischaemic). The purpose of this revision is to update the pathophysiology of the two types of priapism and to create an algorithm of therapeutical and diagnostic approach.

Algorithms↗