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Biomedical subjects

R Ochoa

Publications and source records attributed to R Ochoa.

70 records · Page 4Linked to original sources
PubMed1978

Equine grass sickness: serologic evidence of association with Clostridium perfringens type A enterotoxin.

Clostridium perfringens type A enterotoxin seroneutralization was carried out on sera from 50 horses recovered from grass sickness and from 100 other horses with no record of having had the disease. Of the affected horses, 70% had seroneutralizating titers higher than 1:64, half of these being equal or higher than 1:128. More than 88% of the horses with no record of grass sickness had titers lower than 1:64. These data support the theory of association between C perfringens type A toxins and grass sickness.

Animals↗
PubMedDate not supplied

Use of low-temperature field emission scanning electron microscopy to examine mites.

Partly because mites are microscopic in size and fragile in nature, acarologists estimate that less than five percent of extant species have been taxonomically described. Recently, data from conventional scanning electron microscopy (SEM) have been used to facilitate the descriptions and complement the information that has been historically obtained with the light microscope. However, the conventional preparation techniques associated with SEM frequently prevent or compromise the results. This study evaluated the use of low-temperature field emission SEM to image mites and their hosts. Results indicated that a modified cryofixation procedure, which was associated with this technique, retained the mites at their living/feeding sites in natural behavioral positions. Furthermore, the turgor of the specimens, even eggs and soft-bodied species, was also maintained. The structure and orientation of delicate structures such as setae, which would be subjected to mechanical damage during conventional chemical fixation, dehydration, and drying, were also preserved after cryofixation. Field emission SEM, which provided useful magnification beyond that attainable with a conventional SEM, also enabled resolution of ultrastructural features, such as tenent hairs on the empodium and pores on the dorsal surface that had not previously been observed. These advantages indicate that the low-temperature field emission SEM can provide important structural data that can be used to study the anatomy, morphology, and bioecology of mites.

Animals↗
PubMedDate not supplied

Usefulness of insulin-like growth factor binding protein-3 levels to determine acromegaly activity and effectiveness of transsphenoidal pituitary surgery.

BACKGROUND: Several series reported in the literature concerning the results of the treatment of acromegaly have been difficult to evaluate because the indicators are inaccurate. METHODS: We investigated the usefulness of insulin-like growth factor binding protein-3 (IGFBP) levels to determine disease activity after surgical treatment of acromegaly in 13 patients with confirmed somatotroph adenoma. RESULTS: Before surgery, all 13 non-treated patients had elevated serum levels of IGFBP-3 as well as total and free IGF-I. In addition, there was no overlap with the normal controls (p < 0.001). IGFBP-3 levels correlated significantly (0.91, p < 0.001) with GH suppressibility by glucose after surgery. CONCLUSIONS: These data confirm that IGFBP-3 is a better indicator of acromegalic activity than either total or free IGF-I. There was a high correlation with GH suppressibility by glucose after surgery; both free and total IGF-I could be considered sensitive markers only for diagnosis of active acromegaly but not for efficacy of surgery.

Acromegaly↗
PubMedDate not supplied

Functional improvement with the Sever L'Episcopo procedure.

This was a prospective study to determine the functional results in patients with obstetric palsy treated with the Sever L'Episcopo procedure using a simple five-grade scale consisting of the ability to reach the abdomen (grade 0), upper thorax (grade I), mouth (grade II), forehead (grade III), and occiput (grade IV), which translates into an improvement in basic daily activities. Forty-nine procedures were done in 48 patients (one bilateral) with a preoperative and postoperative evaluation of each case. Range of motion was also recorded for each patient both preoperatively and postoperatively. The overall results showed an improvement of two grades in 61% of our patients. The improvement in range of motion averaged 64 degrees for active abduction and 42 degrees for active external rotation. Functional goals must be the principal concern. With this method of evaluation, we can measure (in a simple way) improvement in the activities of daily living.

Adolescent↗
PubMedDate not supplied

HOXB homeobox gene expression in cervical carcinoma.

The homeobox (HOX) genes are a family of transcription factors that bind to specific DNA sequences in target genes regulating gene expression. Thirty-nine HOX genes have been mapped in four conserved clusters: A, B, C, and D; they act as master genes regulating the identity of body segments along the anteroposterior axis of the embryo. The role played by HOX genes in adult cell differentiation is unclear to date, but growing evidence suggests that they may play an important role in the development of cancer. To study the role played by HOX genes in cervical cancer, in the present work, we analyzed the expression of HOXB genes and the localization of their transcripts in human cervical tissues. Reverse transcription-polymerase chain reaction analysis and nonradioactive RNA in situ hybridization were used to detect HOXB expression in 11 normal cervical tissues and 17 cervical carcinomas. It was determined that HOXB1, B3, B5, B6, B7, B8, and B9 genes are expressed in normal adult cervical epithelium and squamous cervical carcinomas. Interestingly, HOXB2, HOXB4, and HOXB13 gene expression was found only in tumor tissues. Our findings suggest that the new expression of HOXB2, HOXB4, and B13 genes is involved in cervical cancer.

Base Sequence↗
PubMedDate not supplied

Changes in rat heart histomorphometry due to two-week dietary restriction.

In preclinical safety studies in which the administration of a test compound causes reductions in food consumption, body weights, and organ weights, it may be difficult to differentiate direct compound-induced effects on organ weights from those simply due to reduced nutrition. To address this problem in reference to the heart, hearts were obtained from rats that were known to have had reductions in body weights and absolute heart weights as a result of feed restriction. Rats (40/sex) were divided into 4 groups (10/sex) and given quantities of ad libitum diet for 2 wk as follows: Group 1, 100%; Group 2, 75%; Group 3, 50%; and Group 4, 25%. Routine histologic evaluation was performed on longitudinal sections of paraffin-embedded hearts stained with hematoxylin and eosin. Computer-assisted image analysis was conducted on left ventricular free-wall of picrosirius red-stained sections for histomorphometric evaluation of ratio of cross-sectional area occupied by myofibers versus interstitium and for quantification of myofiber width. No differences were detected histologically among groups, and no difference in the mean myofiber: interstitium ratio was detected between Groups 1 (9.1) and 4 (9.5). Mean values for myofiber width ranged from 24.6 microns for Group 1 to 17.3 microns for Group 4. Two-way ANOVA revealed a strong effect of dietary restriction on reduction of myofiber width but no consistent gender effect. The significant dietary effects occurred in Groups 3 and 4 compared to corresponding controls. The present authors speculate that, if reductions in feed intake were < 50% in short-term preclinical studies, any reductions in myofiber width could imply a primary test article effect. Conversely, if reductions in feed intake were > or = 50% in such studies, reductions in myofiber width could be caused either solely by inadequate nutrition or by combined effects of nutrition and test article.

Animals↗
PubMedDate not supplied

Effects of cholestyramine and diet on small intestinal histomorphometry in rats.

Reports on the effects of cholestyramine on small intestinal structure of rats have produced contradictory data about changes in mucosal histomorphometry, perhaps due to interacting effects of dietary composition. In order to identify effects of cholestyramine and diet on structure of the small intestines, 40 male rats were divided into 4 groups of 10 and fed 1 of each of the following diets for 1 month: standard diet, purified fiber-free diet, standard diet + 2% cholestyramine, or purified fiber-free diet + 2% cholestyramine. Serum concentrations of cholesterol and triglycerides were moderately increased in rats fed the purified fiber-free diet versus the standard diet. Neither total length nor weight of small intestine were affected by either diet or cholestyramine. Mucosal weight was affected by interactions between cholestyramine and diet, indicating that outcome depended upon modulating effects of both variables. Significant interactions were similarly detected among the variables of anatomic site, diet, and cholestyramine for many histomorphometric parameters of intestinal mucosa. Cholestyramine reduced total mucosal thickness in both jejunum and ileum and reduced villus height and villus:crypt ratio in the ileum.

Animals↗
PubMedDate not supplied

[Decrease in circulating androgens in men during senescence].

It has been reported that circulating androgens exhibit a decrement with aging in men; however, there are some controversial results. We have carried out a descriptive study in a group of men aged 60-70 years. In order to determine levels of androgens In serum, the results were compared with those obtained in another group in normal men 20-44 years of age. Measurements included circulating levels of testosterone(T), dehydroepiandrosterone sulfate (DHEA-S), LH, FSH, estradiol (E), ACTH, prolactin (PRL), IGF-1, and SHBG. The group of older men group showed a significative decrement of T and DHEA-S, as well as E. An increment of FSH and LH without changes of ACTH, cortisol and SHBG was demonstrated. Collaterally, PRL and IGF-1 decreased in aging men. The present data demonstrated a significant decrement of circulating androgens, both T and DHEA-S coinciding with elevation of gonadotropins. It is concluded that aging is accompanied by changes of a decrement of androgens, of gonads, and adrenal origin. Further studies will investigate the effect of testosterone replacement in aging men.

Adult↗
PubMedDate not supplied

Correction of insulin resistance in methimazole-treated patients with Graves disease.

The effect of thyroid hormone excess on glucose tolerance as well as insulin secretion and its peripheral action has been a matter of debate for many years. Thyrotoxicosis caused by Graves' disease is associated in some patients with impaired glucose tolerance and insulin resistance. The objective of the present study was to investigate if the insulin sensitivity, assessed by the euglycemic insulin clamp technique, increase after correction of hyperthyroidism due to Graves' disease. After four months of medical treatment, patients became euthyroid and insulin sensitivity increased significantly from 3.47 to 6.39 mg/kg/min; therefore it was concluded that insulin resistance could be improved after successful treatment of hyperthyroidism. The precise mechanism underlying the effect of thyroid hormone excess on insulin sensitivity remains to be elucidated.

Adult↗
PubMedDate not supplied

[Molecular heterogeneity of prolactin and gonadotropins in some forms of sterility].

In this paper are presented some chromatographic studies for partition of different molecular forms of prolactin (PRL), follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in infertile women. Serum from three patients with prolactinoma and six with premature ovarian failure were fractionated in Sephadex G-100, and eighty fractions were collected, where PRL or FSH/LH were measured by radioimmunoassay, according with each case. Patients with prolactinoma showed two different chromatographic patterns for PRL. Two women with secondary amenorrhea and galactorrhea showed predominance of "little" PRL. In contrast, the patients with primary amenorrhea and galactorrhea showed only "big" PRL and "big-big" PRL. Among the patients with premature ovarian failure, two had chromosomal mosaicism, two had refractory ovarian syndrome and the other two had idiopathic premature ovarian failure. In these patients were found the presence of several molecular forms of FSH and LH, with different chromatographic profiles to those observed in normal young women and postmenopausal women. These results are indicating the presence of several molecular forms of pituitary hormones in patients with prolactinoma and premature ovarian failure.

Adult↗
PubMedDate not supplied

Hypergastrinemia of newborns and infants during breast-feeding.

OBJECTIVE: We determined gastrin concentrations in newborns and their mothers both before and during lactation. METHODS: Twenty-five women who had uncomplicated pregnancies with normal vaginal delivery of healthy infants at term participated in the study. Twelve preterm neonates with low birth weight (LBW) were also studied. Gastrin levels were determined by radioimmunoassay in amniotic fluid and in serum of both the neonates and their mothers at birth and during breast-feeding. Serum levels of gastrin and prolactin (PRL) were measured in the mothers before and after tactile self-stimulation of the breast. RESULTS: In normal newborns, gastrin levels in cord sera were significantly higher than levels in maternal blood and amniotic fluid at birth. However, gastrin cord sera in LBW newborns was lower than in the normal neonates. Nursing resulted in an increment of serum gastrin levels in the infants and mothers; this rise was similar in the 3 postpartum weeks tested. Tactile stimulus of the mother's nipple resulted in increases of both gastrin and PRL. CONCLUSIONS: Newborns at term show significantly higher gastrin levels than do LBW neonates, which may indicate differences in development of the gastrointestinal system. Breast-feeding induced gastrin secretion in both mothers and infants, confirming the presence of an active vagal reflex. In addition, tactile stimulation of the nipple increased gastrin and PRL levels in the mothers. Our data suggest that LBW neonates have deficient production of gastrin, which in turn may indicate an undeveloped gastrointestinal system. An early enteral feeding triggers the postnatal increase in concentrations of gut hormones.

Adult↗