Biomedical subjects

M A Palumbo

Publications and source records attributed to M A Palumbo.

24 records · Page 2Linked to original sources

PubMed1995

Evidence for a role for the neurosteroid allopregnanolone in the modulation of reproductive function in female rats.

The present study investigated the effect of allopregnanolone (5 alpha-pregnan-3 alpha-ol-20-one) or of passive immunoneutralization of brain allopregnanolone, the most potent steroid produced by neurons, on ovulation rate and sexual behavior in female rats. Allopregnanolone was injected intracerebroventricularly in rats on diestrus and proestrus and tests were done on estrus. The intracerebroventricular injection of allopregnanolone significantly decreased the number of oocytes collected on estrus (p < 0.01). To support a physiological involvement, antiserum to allopregnanolone was injected centrally to block the activity of the endogenous neurosteroid. When administered on diestrus and proestrus or only on proestrus, the antiserum was shown to be correlated with a significant increase (p < 0.01) in oocytes retrieved on estrus. In female rats treated with antiserum to allopregnanolone, the lordosis intensity was augmented significantly as compared to controls. Finally, the possible changes of medial basal hypothalamus concentration of allopregnanolone throughout the estrous cycle and at the time of ovulation were investigated. Hypothalamic extracts were eluted on high-pressure liquid chromatography and allopregnanolone concentration was measured by radioimmunoassay. Brain cortex was used as control tissue. Hypothalamic allopregnanolone concentration on proestrus morning and afternoon was found to be significantly lower than in the remaining phases of the estrous cycle (p < 0.01), while no significant changes were observed in brain cortex concentration of allopregnanolone. The present results suggest that hypothalamic allopregnanolone may be involved in the mechanism of ovulation, affecting hormonal and behavioral events.

Animals↗

PubMed1995

Evidence for a role of neurosteroids in modulation of diurnal changes and acute stress-induced corticosterone secretion in rats.

The neurosteroid allopregnanolone has been shown to be a potent ligand of gamma-aminobutyric acid (GABA)-A receptors and enhances its receptor-mediated inhibitory events. Since central GABA plays a major inhibitory role, via GABA-A receptors, in hypothalamic-pituitary-adrenal (HPA) function in rats, the present study has evaluated the effect of passive immunoneutralization of allopregnanolone on diurnal changes in corticosterone secretion and acute stress-induced corticosterone secretion in rats. In the first protocol, four groups of male rats (prepubertal, fertile, castrated adult and aged) and three groups of female rats (prepubertal, fertile at different phases of the estrous cycle and aged) were studied. Rats were injected intracerebroventricularly (i.c.v.) with 10 microliters anti-allopregnanolone serum or 10 microliters normal rabbit serum (control) 24 h before exposure to an acute cold swimming stress, and sacrificed either before stress or after 5 min stress. In the second protocol, fertile male or female rats at diestrus II were injected i.c.v. with anti-allopregnanolone serum or normal rabbit serum and sacrificed on the following day at 10.00 or 18.00. Truncal blood samples were collected for measuring plasma corticosterone. Our results showed that there was no significant difference in basal plasma corticosterone levels between antiserum-treated and control rats of both sexes. However, in male rats, central injection of antiserum to allopregnanolone significantly potentiated plasma corticosterone response to stress in prepubertal and adult fertile rats as well as in castrated rats. Likewise, in female rats, the stress response of plasma corticosterone was enhanced by passive immunoneutralization of allopregnanolone in prepubertal and fertile rats throughout the estrous cycle.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

Lumbar spinal stenosis: a review.

Lumbar spinal stenosis can usually be identified after a thorough history and physical examination. Most individuals with this condition are successfully treated by non-operative means. Invasive radiologic studies and surgery are reserved for those patients who fail to respond to conservative measures. In these select cases, predictably good results can be expected from lumbar decompression.

Aged↗

PubMed1993

[Health inequalities in Barcelona and Valencia].

BACKGROUND: Inequalities in health have been internationally recognized as an important public health problem with a reduction of 25% being the first target of WHO--Europe for the year 2000. It is, therefore, important to describe and monitor the same. METHODS: An ecological study was performed using secondary data from the statistics of mortality (years 1985-1988) and the municipal censuses from the year 1986 to describe and compare inequalities in health in the cities of Valencia and Barcelona with neighborhoods being the unit of observation and analysis. RESULTS: Although the rates of mortality in Barcelona city are slightly inferior and those of Valencia slightly higher to those of Spain, both cities demonstrate important inequalities in regard to mortality in their neighborhoods with respect to standardized mortality which ranged from 78 to 182 in Barcelona and from 63 to 147 in Valencia. The privileged zones in Barcelona are those of Pedralbes and Sant Gervasi and in Valencia in the neighborhoods of Sant Pau and Jaume Roig with the most unfavorable neighborhoods being District I in Barcelona (Gothic Quarter, City Park, Barceloneta and Raval) and the Na Rovella and Fuensanta neighborhoods of Valencia. The level of inequality in both cities is very similar. Statistically significant associations have been found in both cities between the state of health and the level of poverty in the neighborhoods according to an approximation to the Townsend et al indexes. CONCLUSIONS: The description of important inequalities in two large Spanish cities suggests the possibility of its existence in other cities and established the urgent need for a study using comparable methodologies. With the use of routine and presently available data sources it is possible to describe and posteriorly monitor the level of inequality in large cities in Spain. The development of policies to diminish the inequalities in the large cities would provide considerable gains in terms of human lives. The present results support the hypothesis that material conditions in everyday life play an important role as a condition for public health inequality.

Adolescent↗

PubMed1993

Secondary reconstruction after vascularized fibular transfer.

We evaluated the results of skeletal reconstruction performed through a mature, vascularized fibular graft in five patients. The average time-interval between the original transplant and the secondary reconstruction was sixty-eight months. The indication for the initial graft had been the loss of bone secondary to trauma in one patient, a skeletal defect due to ablation of a tumor in two patients, and osseous loss due to resection of a congenital pseudarthrosis in two patients. The indication for the second reconstruction was non-union of a fracture as a result of a new traumatic injury in two patients and complex angular deformity in three patients; one of the patients in the latter group had an associated leg-length discrepancy. In all five patients, the second reconstruction was successful, and the vascularized fibular graft responded to the procedure in a manner similar to normal cortical bone.

Adolescent↗

PubMedDate not supplied

The effect of protective football equipment on alignment of the injured cervical spine. Radiographic analysis in a cadaveric model.

No universally accepted management protocol is available for dealing with the protective equipment worn by a neck-injured football player. The purpose of this cadaveric study was to determine the effects of the helmet and shoulder pads on the alignment of 1) the intact lower cervical spine and 2) the partially destabilized C5-6 motion segment. In Group I cadavers (N = 15), the lower cervical spine was tested in an intact condition. In Group II (N = 8), the C5-6 motion segment was tested in both an intact and a partially destabilized condition. Each cadaver was placed supine on a backboard and four lateral cervical radiographs were obtained as follows: no protective equipment, helmet only, helmet and shoulder pads, and shoulder pads only. Results for Group I showed that wearing both helmet and shoulder pads did not result in a significant change in cervical lordosis when compared with the neutral position (i.e., the no-equipment test). Cervical lordosis was significantly decreased in the helmet-only category (mean, 9.6 degrees) and significantly increased in the shoulder pads-only category (mean, 13.6 degrees). In Group II, destabilized specimens under the helmet test situation showed a significant mean increase in C5-6 forward angulation (16.5 degrees), posterior disk space height (3.8 mm), and dorsal element distraction (8.3 mm). Immobilizing the neck-injured football player with only the helmet or only the shoulder pads in place violates the principle of splinting the cervical spine in neutral alignment, according to our findings. We support the concept that removal of the helmet and shoulder pads should be an all-or-none proposition.

Aged↗