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D G Montemurro

Publications and source records attributed to D G Montemurro.

17 recordsLinked to original sources
PubMed1997

Magnetic resonance imaging volumetric and phosphorus 31 magnetic resonance spectroscopy measurements in schizophrenia.

The purpose of this study was to examine the relationship between phosphorus magnetic resonance spectroscopy (31P MRS) parameters and left prefrontal volumes in both patients with schizophrenia and healthy subjects. 31P MRS parameters and magnetic resonance imaging (MRI) volumetric data were collected in the left prefrontal region in 10 patients with schizophrenia and 10 healthy subjects of comparable age, handedness, sex, educational level, and parental educational level. No correlations were found between any MRS parameter and grey matter volumes in the combined subjects. Phosphomonoester (PME) and grey matter volumes, however, were both correlated negatively with age. PMEs were found to be decreased, and calculated intracellular magnesium ([Mg2+]intra) was found to be increased in the patients with schizophrenia compared with healthy subjects after adjusting for left prefrontal grey and white matter, total brain volume, and age. These findings suggest that cortical grey and white manner volumes are not directly related to PME and [Mg2+]intra abnormalities in schizophrenia patients.

Adult↗
PubMed1982

Ovulation in the rabbit following intraventricular and intravenous administration of synthetic Gn-RH.

A comparison was made of the efficacy of intravenously (iv) and intraventricularly administered synthetic Gn-RH in inducing ovulation in conscious and urethane anaesthetized rabbits. Via the iv route of administration, the minimum dose of Gn-RH required to induce ovulation in all animals of the conscious group was 300 ng/kg body weight. This is in contrast to the larger systemic dose (400 ng/kg body weight) of Gn-RH required to achieve the same results in urethane anesthetized but otherwise identically treated rabbits. This suggests that although ovulation is no blocked by an anaesthetic dose of urethane (1.25 g/kg), the ovulatory response is altered in some way by the anaesthetic. When administered intraventricularly, the minimum dose of Gn-RH required to induce ovulation in anaesthetized animals was only 100 ng/kg body weight or 25% of the equivalent systemic dose. Systemically ineffective doses of Gn-RH (less than or equal to 200 ng/kg body weight) also induced ovulation in the anaesthetized group when administered via the third cerebral ventricle. All animals that ovulated did so between 13 and 16 h following Gn-RH administration and the number of ova recovered paralleled the number of ruptured follicles. A graded increase in the number of ova released with dosage of Gn-RH was not observed. In this study, the smaller defective dose requirement for intraventricularly administered decapeptide supports the view that Gn-RH in the CSF circumvents the general circulation and reaches the portal vasculature directly via the median eminence.

Animals↗
PubMed1975

Neurosecretory activity within suprachiasmatic neurons of the female rabbit following castration.

The effects of ovariectomy on the ultrastructure of neurons within the SCH nuclei of the rabbit were investigated. All SCH neurons of the intact controls were similar in that they showed no morphological evidence of enhanced neurosecretory activity. In contrast, two distinct types of neurons were present within the SCH nuclei of the ovariectomized animals. The small, Type I neurons were ultrastructurally identical to the SCH neurons of the intact controls. The larger, Type II neurons, on the other hand, clearly presented structural evidence for elevated intraneuronal synthesis. To ensure that the changes which characterized the Type II neurons were due, at least in part, to the removal of ovarian steroids following ovariectomy and not to surgical stress alone, the SCH nuclei of laparotomized rabbits were also studied. Although the same two neuron types were observed, the number of Type II neurons in the laparotomized controls was significantly smaller (p smaller than 0.001) than the number in the ovariectomized group. These findings suggest that Type II neurons probably represent a functional state of the smaller, non-active neurons of the intact controls. In addition, the ultrastructural features that distinguish type II neurons are positively related to the endocrine state of the rabbit and, therefore, may represent the hypothalamic synthesis of the releasing hormones that control is gonadotropic activity.

Animals↗