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Biomedical subjects

R Cabrera

Publications and source records attributed to R Cabrera.

At least 91 records · Page 5Linked to original sources
PubMed1993

[Anorectal manometry in the newborn].

Anorectal manometry was performed in 32 newborn. There were 18 preterm and 14 fullterm infants, mean ages 6.1 and 7.1 days respectively. The rectoanal inhibitory reflex (RIR) was positive in 31 of the newborn, and the relaxation waves produced by rectal distention were recorded along the anal canal and were directly correlated to intensity of the stimulus. In the remaining patient RIR was negative, due to Hirschsprung's disease, confirmed at surgery. The length of the anal canal was 10.3 +/- 2 mm. in preterm newborn infants and 14.7 +/- 2.9 mm, in fullterm (p < 0.0001). These findings suggests that presence of RIR is independent of the weight, gestational age and birth age of the infant, and that anal canal length is correlated with the weight of the infant. We conclude that anorectal manometry, in the neonatal period, is a simple, reliable and safe method to test anorectal functionality, including the study of Hirschsprung's disease.

Female↗
PubMed1993

The immunology of scabies.

Individuals with scabies react to bites by generating a cell-mediated immune response at the bite site. This elicits a very itchy papule that is often excoriated. Sometimes ulcerated papules, vasculitis, and nodules develop as a result of other immunologic reactions in skin. Immunologic reactions mediated by antibodies of the immunoglobulin G (IgG), IgM, and especially, IgE classes may also be involved. None of these reactions have been shown to eliminate all mites from the skin surface, but locally these reactions may prevent the epidemic multiplication of scabies' organisms on the skin surface, as observed in some patients with crusted scabies.

Acquired Immunodeficiency Syndrome↗
PubMed1991

[Determination of the neurotransmitters 5-hydroxytryptamine, noradrenaline, and dopamine in gastroduodenal mucosa. Clinical and histologic correlation].

We have studied the concentrations (pg/mg) of Neurotransmitters 5-hydroxytryptamine (5HT), Noradrenaline (NA) and Dopamine (DA) at mucosa normal and with different degrees of chronic inflammation mucosa of fundus (F), antrum (A) and duodenum (D) in 21 patients. We correlated the concentration of the neurotransmitters with each other, all of them in each region and with clinics, indirect of motility and histologic parameters. The average for 5HT in F: 940.2 +/- 457.4; in A: 787.5 +/- 407.0; in D: 601.6 +/- 272.0; for NA in F: 217.5 +/- 138.7; in A: 228.4 +/- 126.5; in D: 245.7 +/- 118.6 for DA in F: 50.7 +/- 32.2; in A: 46.3 +/- 31.5; in D: 53.0 +/- 45.6. The statistical analysis showed a significant correlation of DA concentration with lymphoplasmocytic infiltrated in Duodenum (r = 0,94). not any other parameter had significative relation with the neurotransmitters variations. We established that the variations of the neurotransmitter concentrations of the antrum mucosa are more associated with the duodenum than with the gastric fundus.

Adult↗
PubMed1990

Neonatal chronic stress induces subsensitivity to chronic stress in adult rats. I. Effects on forced swim behavior and endocrine responses.

An influence of early stimulation on sensitivity to acute stress in adulthood has been reported. The purpose of the present work was to determine the effect of exposure of male and female rats to three models of chronic stress (unpredictable stress, cold stress and handling) from day 2 to day 15 of life on behavioral and endocrine sensitivity to chronic stresses in adulthood. The chronic stresses applied in adulthood were a model of intermittent cold stress (daily 30-min sessions at -20 degrees C for 15 days) and the Katz's model of unpredictable chronic stress (15 days). Forced swim behavior and serum concentration of the stress-sensitive hormones, corticosterone and prolactin, were chosen to investigate stress sensitivity. It was found that all neonatal treatments stimulated body weight gain, did not cause infant mortality and did not affect forced swim behavior as adult. The repetitive exposure to cold stress in adulthood did not cause major impairment of forced swim behavior and did not affect basal levels of serum corticosterone and prolactin in either control or experimental rats. These findings support the view that repeated stressors can induce behavioral and endocrine adaptation in rats. The neonatal treatments did not affect this characteristic. The exposure of control rats to the unpredictable stress model severely impaired forced swim behavior and increased basal levels of serum corticosterone and prolactin. This observation conforms to the view that standard laboratory rats cannot adapt to unpredictable chronic stress. This has been reported to cause a behavioral depression syndrome comprising forced swim deficit and endocrine alterations.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1990

Effect of experimentally-induced chronic hyperprolactinemia on insulin binding and antilipolytic response in adipocytes from male rats.

Male Wistar rats with chronic hyperprolactinemia induced by grafting an anterior pituitary gland under the right kidney capsule were studied as experimental model. In these animals basal plasma glucose and insulin levels were unaltered. Epididymal adipocytes from hyperprolactinemic rats showed a significant increase in insulin binding at low unlabeled insulin concentrations. This increase in insulin binding can be principally attributed to an increase in the high affinity-low capacity binding sites, as demonstrated when Scatchard analysis was interpreted in terms of two types of insulin receptors. The dissociation constants (KD1 and KD2) were not different between the groups. The apparent insulin receptor affinity was also unchanged. Moreover, a decreased sensitivity to the antilipolytic effect of insulin was also obtained in adipocytes from hyperprolactinemic rats. These findings indicate that chronic hyperprolactinemia is able to increase high affinity insulin receptors in epididymal adipocytes, but tends to diminish the antilipolytic response, suggesting a lack of coupling between insulin binding and its biological activity in male adipose tissue. Several possible mechanisms involved in the process are suggested.

Adipose Tissue↗
PubMed1989

Effect of long-term nickel ingestion on insulin binding and antilipolytic response in rat adipocytes.

Male Wistar rats of the third generation of rats drinking 200 micrograms Ni2+/mL as NiCl2 in their drinking water were studied. Basal plasma glucose and insulin levels were unchanged. Epididymal adipocytes from Ni2(+)-fed rats showed an increased insulin binding with a slight increase in apparent insulin affinity (ED50: Ni2(+)-fed rats 2.8 x 10(-9) M and controls 5 x 10(-9) M) with no change in insulin receptor numbers (Ni2(+)-fed rats 143,000 +/- 12,000 (6) receptors/cell and controls 126,000 +/- 13,000 (5]. Moreover, a decreased sensitivity to the antilipolytic response of insulin was also observed in adipocytes from Ni2(+)-fed rats. These events could represent actions of Ni2+ both at the receptor and post-receptor insulin levels. Several possible mechanisms involved in the process are suggested.

Adipose Tissue↗
PubMed1989

[Interstitial pneumonia in bone marrow transplantation. Preventive and therapeutic aspects. Our experience and review of the literature].

From June/82 through November/85 bone marrow transplant recipients in our Institution were given only trimethoprim-sulfamethoxazole as prophylaxis against interstitial pneumonia. In December/85 we began a program of administration of passive immunoprophylaxis with hyperimmune plasma or cytomegalovirus-specific gamma globulin and transfusion of seronegative blood products to all bone marrow transplant recipients whether they were seropositive or seronegative prior to transplant. Nine of 36 patients in the historical control group and 9 of 32 patients in the study group developed an interstitial pneumonia. Interstitial pneumonia, once established, was treated empirically. The 9 patients in the control group received trimethoprim-sulfamethoxazole +/- adenine arabinoside, acyclovir, amphotericin B and anti-bacterial antibiotics; all died. Post-mortem study was performed in 7 (4 CMV, 3 idiopathic). The 9 patients in the study group received high dose cytomegalovirus-specific gamma globulin + acyclovir or ganciclovir in addition to the above measures. Four were cured, one relapsed and responded to treatment again. Five died (1 CMV, 1 candida, 3 idiopathic). We conclude that the prophylactic measures, as applied at our Institution, were inefficient. By contrast, therapy with specific immunoglobulin + acyclovir or ganciclovir can control a high percentage of patients. We compare this experience with reports from other centers.

Acyclovir↗
PubMed1989

Validation of single photon absorptiometry in estimating bone mineral mass in rhesus monkey skeletons.

Recent emphasis on age-related morbidity addresses the increasing life expectancy of Western countries. Osteopenia is a multi-factorial process affecting a sizeable number of elderly individuals, with bone fractures producing significant morbidity and related mortality. A non-human primate would be a very useful experimental model for the study of age-related osteopenia, if it could be shown that it is similarly afflicted by age and if non-invasive methods utilized among humans could give a valid estimation of bone mineral content in the animal. Our previous studies utilizing SPA (single-photon absorptiometry) suggest age-related decrease in BMC (bone mineral content) among rhesus macaque skeletons, similar to that observed in humans. The present studies were done in order to further validate the utilization of bone densitometry (SPA) in the rhesus macaque, comparing their BMC and bone density (BD) with the size and weight of their corresponding bones. Both radii and the right femur of 102 adult rhesus monkey skeletons (5 to 23 years old), were obtained from the Caribbean Primate Research Center (CPRC) Skeletal Collection. There were 55 females and 47 males. Bone parameters were obtained using a Norland Digital Bone Densitometer, model 2780 at 2 scanning sites: distal 1/3 of radii and proximal 1/3 of femurs. Bone lengths (cm) and weights (gm) were compared and correlated with densitometric parameters. Excellent correlations were consistently found, with r values 0.74 to 0.96 and p less than 0.0001. Thus it appears that SPA at distal 1/3 radius or proximal 1/3 femur are a valid estimate of total bone mineral mass in rhesus monkeys.

Academies and Institutes↗
PubMed1988

A further analysis of behavioral and endocrine effects of unpredictable chronic stress.

Tolerance can develop when rats are repeatedly exposed to some predictable stressors. This does not occur, however, when rats are exposed to unpredictable chronic stress. In this study we have analyzed some behavioral and endocrine effects in male and female rats treated daily with unpredictable emotional stressor (ES-groups) or unpredictable physical stressors (PS-groups) over a 14-day period. Animals were then submitted to three behavioral tests at 24 hr intervals. Experiment 1 shows that when rats were tested in an enriched environment both total motor activity and exploration of the novel object were impaired by the PS treatment. This suggests the occurrence of motivational deficit. The fact that the PS-groups also showed increased intratest defecation suggests increased emotionality. When animals were submitted to an emergence test the PS-groups showed longer emergence latency, lower frequency of emergencies and lower time spent exploring the emergence compartment than the ES- and the C-group. This strongly supports that the PS treatment increased emotionality in rats. When ES- and PS-groups were exposed to a forced swim test they showed longer immobility duration (despair reaction) but only the PS-group displayed lower frequency of jumps (escape reaction). Results of all tests performed revealed that females were more resistant than males to the behavioral effects of the PS treatment. The day after the behavioral testing was completed, basal levels of corticosterone and prolactin were investigated in male subjects. The PS-group showed higher baseline levels of these "stress labile" hormones than the ES and the C-group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Insulin binding and action on adipocytes from female rats with experimentally induced chronic hyperprolactinemia.

We studied insulin binding and action in adipocytes from female rats with chronic hyperprolactinemia induced by grafting an anterior pituitary gland under the right kidney capsule. Normal basal insulin plasma levels were detected. An increase in insulin binding due to an increased number of receptors was observed (grafted: 193,000 +/- 13,000 (6) receptors/cell vs. controls: 136,000 +/- 17,000 (6) receptors/cell, P less than 0.05). No changes in receptor affinity were detected (ED50 grafted: 2.3 X 10(-9) M and ED50 controls: 1.6 X 10(-9) M). The antilipolytic activity of insulin was significantly decreased in adipocytes from rats with hyperprolactinemia, indicating an insulin-resistant state in these animals. These findings suggest that the chronic hyperprolactinemic state can modify receptor and post-receptor insulin events in rat parametrial adipose tissue.

Adipose Tissue↗
PubMed1982

Effects of oral atenolol and propranolol on blood pressure, heart rate and plasma cyclic adenosine 3':5'-monophosphate in borderline hypertensive patients.

The effects of oral treatment with atenolol and propranolol on blood pressure, heart rate and plasma cyclic adenosine 3':5'-monophosphate (cAMP) were studied in a group of young borderline hypertensives. Observations were accomplished after a period of recumbent relaxation and also following physiological stress testing. The latter significantly increased blood pressure, heart rate and plasma cAMP. A direct relationship was found between heart rate and plasma cAMP at rest and also following psychological stress. This relationship was lost following drug treatments. Both beta-blockers significantly reduced all measured variables in both conditions. However, plasma cAMP was most affected by propranolol.

Adolescent↗