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Biomedical subjects

J J Maccabe

Publications and source records attributed to J J Maccabe.

At least 19 recordsLinked to original sources
PubMed1992

The evaluation of patients with a suspected pituitary microadenoma: computer tomography compared to magnetic resonance imaging.

OBJECTIVES: To perform a prospective study to compare the ability of magnetic resonance imaging (MRI) and computer assisted tomography (CT) to predict the position of a tumour within the pituitary fossa and to assess the clarity of the image generated by the two modalities in patients with suspected pituitary microadenomas. DESIGN: Nineteen patients were investigated with CT and MRI scans and underwent trans-sphenoidal exploration of the pituitary fossa. Both scans were assessed blind and independently by three neuroradiologists, A, B, and C; A and B examined the CT scans and B and C the MRI scans. The predicted site was then compared to the size and position of the tumour at surgery. PATIENTS: Twenty-five patients were recruited and had both CT and MRI scans, 19 subsequently underwent trans-sphenoidal exploration of the pituitary fossa and formed the study population. RESULTS: The joint opinions of A and B of the CT scans were correct in 10/19, and those of B and C of the MRI scans were correct in 17/19 cases, P = 0.008. Observer agreement was used to assess the clarity of the image. A and B agreed about the site of the tumour on the CT scan in 14 of 19 cases (Kappa statistic 0.556); B and C agreed on the MRI scans in 19/19 cases (Kappa statistic 1), P = 0.025. After the exclusion of five cases found to be macroadenomas at surgery, the joint opinions of A and B of the CT scans were correct in 8/14, and those of B and C of the MRI scans were correct in 12/14 cases, P = 0.133. A and B agreed about the site of the tumour on the CT scan in 12/14 cases (Kappa statistic 0.653), B and C agreed on the MRI scans in 14/14 cases (Kappa statistic 1, no significant difference). CONCLUSIONS: In the assessment of suspected pituitary microadenomas MRI is the imaging technique of choice in view both of its greater diagnostic accuracy and the avoidance of radiation exposure.

Adenoma↗
PubMed1990

CV205-502, a new non-ergot dopamine agonist, reduces prolactinoma size in man.

Seven patients with large prolactin-secreting pituitary adenomas were treated for 8 weeks with once-daily doses of the new, potent, non-ergot, long-acting dopamine agonist CV205-502. In five patients previous treatment with bromocriptine had failed to control their disease or been poorly tolerated and had therefore ceased. In all seven patients serum prolactin levels fell over the 8-week period of CV205-502 treatment with the decrease ranging from 33 to 99%. Associated with this decline in prolactin all patients showed symptomatic improvement with two of the five women beginning to menstruate and the two patients with visual field impairment showing marked improvement. Tolerance of the drug, with doses at 8 weeks ranging from 0.075 to 0.3 mg, was excellent with only minimal and transient side-effects being noted in three patients in none of whom was discontinuation of therapy necessary. In one patient noncompliance after 6 weeks of therapy was associated with a rapid return of her serum prolactin towards pretreatment levels. In all seven patients the clinical and biochemical improvement was accompanied by a marked reduction in tumour size.

Adult↗
PubMed1986

Infarction of a growth hormone-secreting macroadenoma during a TRH test.

Pituitary infarction occurring immediately after TRH injection (200 micrograms) is reported in a patient with gigantism due to a growth hormone-secreting pituitary macroadenoma. Evidence of infarction was seen in CSF and in serial CT scans. Regression of symptoms and sign of acromegaly, abolition of abnormal growth hormone secretion, and virtually complete anterior and partial posterior pituitary failure rapidly followed. The infarction was probably initiated by a hypertensive response to TRH. TRH testing in acromegalic subjects may require smaller doses of TRH to avoid unwanted pressor responses.

Acromegaly↗
PubMed1982

Unilateral removal of the second somatosensory projection cortex in the monkey: evidence for cerebral predominance?

The second somatosensory projection cortex (area SII) was removed unilaterally in 18 monkeys: alone, in 6; with bilateral removals of the supplementary motor area (SMA), in 4; with bilateral removals of anterior parietal association cortex, namely area PF (or 7b), in 4; and with neocortical commissure section, in 4. In half of these monkeys SII was removed from the hemisphere opposite to the preoperatively preferred hand, in half from the hemisphere on the same side as the preferred hand. Histological findings in all 18 monkeys indicated no consistent difference between the lesions (site, extent or depth) of the 9 monkeys with contralateral and the lesions of the 9 monkeys with ipsilateral removals of SII. These 18 monkeys, together with 6 additional unoperated control monkeys, were required to learn to make tactile discriminations, either with their preferred or with their nonpreferred hand. The discriminations were either between pairs of solid objects, or between graded differences in roughness or size. The monkeys with SII removal from the hemisphere contralateral to their preoperatively preferred hand were significantly impaired relative to the ipsilateral group or to the control group irrespective of the hand used (postoperatively preferred or nonpreferred hand). Such impairment was evidenced on the majority (but not all) of the tasks used in this study. In general, removal of SII from the ipsilateral hemisphere did not produce impairment, and bilateral removals of SMA combined with a unilateral removal of SII failed to give rise to additional impairment. However, bilateral removal of area PF, as also commissure section, did produce additional impairment, but only in animals of the ipsilateral group and when the postoperatively nonpreferred hand was required to be used. Certain of the behavior variations within groups can be explained in terms of weak preoperative hand preferences, or by reference to the histological findings for these animals. In general we conclude that the monkey has a degree of cerebral predominance of the hemisphere opposite to the preferred hand, possibly in relation to bilateral somatosensory representation.

Animals↗
PubMed1981

Diaphragm pacing in ventilatory failure.

Diaphragm pacing, which entails electrical stimulation to the phrenic nerve, is an effective means of managing patients with ventilatory insufficiency and intact lowermotor-neurone innervation of the diaphragm. The pacing apparatus is used to pace the right and left hemidiaphragms alternately to avoid fatigue, which may damage the muscle irreversibly. Among the important benefits of pacing in quadriplegics with paralysis or respiratory muscles are the social and psychological advantages of not being dependent on a mechanical ventilator.

Adult↗
PubMed1980

Metastatic trophoblastic disease presenting as a subarachnoid hemorrhage: report of two cases and review of the literature.

Trophoblastic tumors may present as subarachnoid or intracerebral hemorrhages in women of childbearing age. Although uncommon in Western countries, they constitute a significant percentage of metastatic lesions to the nervous system among Oriental women and usually follow molar pregnancies. Malignant transformation may occur at any time, but most frequently within a year of pregnancy. For this reason, close follow-up of women with molar pregnancies and subsequent prevention of pregnancy for one year is mandatory. Persistent serum human chorionic gonadotropin elevations are seen at some stage. Eighty percent of hydatidiform moles remit spontaneously, and the prognosis for persistent molar disease treated with chemotherapy and irradiation is good. The prognosis for choriocarcinoma, however, is less favorable. Subarachnoid hemorrhage may be the first and only sign of intracerebral bleeding into a metastatic lesion or leakage from a damaged vessel in which trophoblastic tissue has lodged. The triad of menstrual abnormalities, recent or remote pregnancy or abortion, and an acute cerebrovascular event with evidence of a mass lesion should suggest the diagnosis of metastatic trophoblastic disease in a woman of childbearing age.

Adult↗
PubMed1978

The effects of ablations on primary and secondary epileptic discharges in commissure-sectioned rhesus monkeys.

Nine monkeys underwent division of the corpus callosum, anterior commissure, massa intermedia, and posterior commissure. At the same operation, in seven of these animals aluminium hydroxide was applied to the left posterior parietal-prestriate cortex. Monthly EEG recordings were taken from all animals. All seven animals with epileptogenic implants gave evidence of primary abnormal discharges (i.e. from the ipsilateral hemisphere) and secondary (i.e. from the contralateral hemisphere) discharges. The secondary events were of two types: transmitted, i.e. synchronous with primary events; independent, i.e. asynchronous with primary events. After intervals varying from 4 to 22 months all seven monkeys underwent wide ablation of the posterior parietal cortex: on the left in four animals, on the right in three animals. EEG recordings were taken for a further 6 months. All recordings were quantitatively analysed, the number of primary, transmitted secondary and independent secondary events being counted separately. This analysis indicated the following: (1) Primary and transmitted secondary discharges ceased after primary ablations but were unaffected by removal of the secondary cortex. (2) Independent secondary discharges persisted after removal of the primary focus but were abolished by secondary ablations. Possible mechanisms for the development of transmitted and independent secondary discharges are considered.

Aluminum Hydroxide↗
PubMed1975

Intermanual transfer in the monkey as a function of amount of callosal sparing.

The effects of commissure section, task difficulty and overtraining on the intermanual transfer of tactile learning have been examined. Twenty-one rhesus monkeys were allocated to 4 groups. One group was subjected to complete transection of the corpus callosum, massa intermedia and posterior commissure. Some of this group also sustained a cerebellar section. A second group received a similar division of the commissures but with part of the posterior body of the corpus callosum left intact. A third group received similar division of the commissures but with the posterior commissure left intact. The fourth group formed an unoperated control group. Animals with only the posterior commissure left intact showed little or no transfer. Animals with partial callosal lesions showed significantly greater transfer than animals with total transections, but were impaired relative to the unoperated controls. Estimates have been made of the number of callosal fibres left intact in the animals with partial callosal lesions. These estimates have been correlated with transfer. The correlation was significant on only one task. Neither task difficulty nor overtraining were found to affect transfer significantly. The comparison of transfer of the submodalities of size and roughness was inconclusive.

Animals↗