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Biomedical subjects

M H Weiss

Publications and source records attributed to M H Weiss.

At least 127 records · Page 7Linked to original sources
PubMed1983

Bromocriptine treatment of prolactin-secreting tumors: surgical implications.

Ten of 19 patients with Stage III-IV prolactin-secreting tumors experienced significant reduction in the size of the tumor when treated with therapeutic doses of bromocriptine. Those tumors that responded favorably to preoperative pharmacological manipulation were found to have an improved surgical cure rate. These preliminary data suggest that a preoperative effort to reduce the size of large prolactin-secreting tumors may result in significant improvement of our surgical ventures.

Adult↗
PubMed1982

Adenoma of the human pituitary producing growth hormone and thyrotropin. A histologic, immunocytologic and fine-structural study.

A pituitary adenoma removed by surgery from a 22-year-old man was studied by histology, immunocytology, transmission electron microscopy and immunoelectron microscopy. Clinically, the patient had acromegaly and euthyroidism with elevated blood GH concentrations. Blood TSH and T4 levels were within the normal range. Histologically, the adenoma was chromophobic and exhibited no PAS, lead hematoxylin, aldehyde thionin or Grimelius silver positivity. By the immunoperoxidase technique GH, beta-TSH and alpha-subunit but no PRL, ACTH, alpha-endorphin, beta-FSH or beta-LH were demonstrated in the adenoma cells. Electron microscopy revealed adenoma cells which were similar to TSH cells and showed no resemblance to GH cells of nontumorous pituitaries or GH-secreting tumors. Immunoelectron microscopy demonstrated GH and beta-TSH in the secretory granules. It is concluded that pituitary adenomas composed of TSH-like cells may secret GH, resulting in acromegaly. Production of GH by adenomatous TSH cells cannot be explained on the basis of the one cell- one hormone theory. The question is raised whether bihormonal or multihormonal clones, capable of synthesizing more than one hormone, exist in the human pituitary. These cells are apparently dormant under normal conditions, but in the course of neoplastic transformation may undergo functional dedifferentiation and acquire the ability to produce two or more different hormones.

Adenoma, Chromophobe↗
PubMed1982

Transcallosal, interfornicial approaches for lesions affecting the third ventricle: surgical considerations and consequences.

A group of 11 patients with a variety of lesions affecting the 3rd ventricle have been treated using a direct transcallosal interfornicial approach to the region. In 3 patients, no attendant hydrocephalus was present. In an effort to minimize potential cortical injury related to the approach, we studied the venous anatomy in the region of the coronal suture. Based on this study, appropriate flap placement and interhemispheric entry points were defined. Although no lasting, clinically apparent morbidity was observed in any of the 11 cases, we performed more sophisticated studies of the interhemispheric transfer of somesthetic and perceptual motor tasks, as well as psychometric testing related to parameters of intelligence and memory, 3 to 8 months postoperatively in 6 cases. The results and clinical material indicate that this surgical technique is a safe, feasible alternative in the management of a wide spectrum of pathological lesions within this region. A transcallosal, interfornicial approach offers excellent visualization of the entire 3rd ventricle without the dependence on hydrocephalus or an extensive extra-axial mass to enhance the exposure. With proper planning and technique, it may be accomplished with a minimum of physiological consequence.

Brain Diseases↗
PubMed1982

Cerebrospinal fluid drainage as influenced by ventricular pressure in the rabbit.

Artificial cerebrospinal fluid (CSF) containing radioisotope iodinated (125I) serum albumin (RISA) and either blue dextran or indigo carmine was given to white New Zealand rabbits over 4 hours. In one group it was given by ventriculocisternal perfusion, in one by ventricular infusion, and in one by cisterna magna infusion. Blood was sampled continuously from the superior sagittal sinus (SSS) or intermittently from the systemic arterial circulation. Removal of CSF from the cisterna magna during the ventriculocisternal perfusion kept the intracranial pressure (ICP) at 0 to 5 torr, whereas ventricular or cisterna magna infusion raised the ICP to 20 to 30 torr and 15 to 20 torr, respectively. In the two groups with raised ICP, an increased concentration of RISA was present in the optic nerves, olfactory bulbs, episcleral tissue, and deep cervical lymph nodes; but this was not found in the group with normal ICP. In all three groups, the concentration of RISA in the SSS blood was the same as in the systemic arterial blood. The concentration gradient of RISA across the cerebral cortex was similar in both the ventriculocisternal perfusion and the ventricular infusion groups. With cisterna magna infusion, the concentration of RISA was the same on the cortical surface and less in the ventricles compared with the ventricular infusion. It is concluded that, with elevated ICP, CSF drained via pathways that are less evident under normal pressure. Drainage of CSF was similar irrespective of whether the infusion site was the ventricles or cisterna magna. It did not appear that acute dilatation of the ventricles during ventricular infusion compromised the subarachnoid space over the surface of the hemisphere, as the concentration of RISA on the convexities and in the SSS blood did not significantly differ between the groups. Transcortical bulk transfer of CSF was not evident with raised ICP.

Animals↗
PubMed1981

Acidophil stem cell adenoma of the human pituitary: clinicopathologic analysis of 15 cases.

In material of 347 surgically removed pituitary adenomas, 15 tumors (4.3%) were diagnosed as acidophil stem cell adenomas. These are immature neoplasms, assumed to derive from the common progenitor of growth hormone and prolactin cells, and usually containing both hormones by the immunoperoxidase technique. Clinically, they are regularly associated with hyperprolactinemia. Some patients may exhibit physical stigmata of acromegaly without biochemical evidence of the disease ("fugitive acromegaly"). The entity is also characterized by (1) relatively short clinical history; (2) large (grade III--IV), locally invasive adenoma, and (3) relatively low hormonal activity. By electron microscopy, these tumors are unicellular with immature cytoplasm, exhibiting some features of adenomatous growth hormone and prolactin with immature cytoplasm, exhibiting some features of adenomatous growth hormone and prolactin cells and frequently mitochondrial abnormalities as well. They are more aggressive than the well-differentiated adenomas of the "acidophil" cell line--a fact to be considered in postoperative management.

Adenoma, Acidophil↗
PubMed1981

The utilization of native glioma antigens in the assessment of cellular and humoral immune responses in malignant glioma patients.

Cellular and humoral components of the immune response have been studied preoperatively, concurrently, and serially in patients with malignant glial neoplasms. In order to assess titres of circulating antibodies to tumour cell constituents an indirect immunofluorescent technique was applied to single cell suspensions and snap frozen cell smears. In an allogeneic system, 49% of 47 test and 7% of 124 control sera gave a positive response to cytoplasmic components. The leucocyte adherence inhibition assay was applied to study 39 test and 64 control patients. Significant non-adherence of leukocytes was observed in 77% of test cases. Control parameters indicated specificity of the response. Simultaneous assessment in 28 test patients yielded a positive response for one or both assays in 89% of cases..

Antibodies, Neoplasm↗
PubMed1980

Monolayer and suspension culture of human prolactin-secreting pituitary adenoma.

In order to study the hormonal characteristics of human prolactin-secreting pituitary adenomas, in vitro monolayer and suspension cultures from human pituitary glands were established. Optimal conditions for cultures included enzymatic dispersion into viable single-cell suspensions with the use of 1% collagenase in phosphate-buffered saline solution. After pelleting the dispersed cells by centrifugation (800 rpm for 10 minutes), they were cultured in RPMI medium that contained 20% fetal calf serum and then incubated at 37degrees C in 5% CO2. Cells were subcultured weekly at a ratio of one plate to two. In an attempt to establish whether bromocriptine has a direct inhibitory effect on pituitary secretion of prolactin (PRL), variable doses of bromocriptine were added to duplicate plates. The addition of bromocriptine to the culture medium induced suppression of PRL within 7 days. In conclusion, this study demonstrated that either monolayer of suspension cultures of human PRL secreting adenomas can be established, and that bromocriptine in doses of 1 ng/plate or more has a direct inhibitory effect on the secretion of PRL.

Adenoma↗
PubMed1980

Correlative ultrastructural morphometry of human prolactin-producing adenomas.

Ultrastructural morphometry was applied to 24 surgically removed human sparsely granulated prolactin cell adenomas in an attempt to correlate the measurements with blood prolactin levels, size of tumour, and age and sex of patient. No correlation was apparent. However, further evaluation revealed that correlation existed between size of tumour and blood prolactin levels, indicating that tumour mass, and not subcellular morphology, was related to the amount of prolactin released.

Adenoma↗
PubMed1980

Gunshot wounds to the brain--a civilian experience.

A study involving 79 patients who were considered for surgical treatment for craniocerebral gunshot injuries between 1972 and 1978 was carried out to develop criteria for radiographic assessment and surgical operation, as well as to improve operative techniques and preoperative planning. The study focused on differences between military and civilian injuries, as well as criteria for gross prediction of outcome. Of note in the overall perspective of the series were (1) the predominance of low-velocity missiles, (2) the high rate of self-inflicted injuries (34 percent), (3) the overall mortality of 23 percent with the rate for persons older than 60 being approximately 70 percent, (4) the correlation between preoperative patient assessment and mortality, (5) complications predominated by cerebrospinal fluid fistulas (10 percent), (6) the value of computerized axial tomographic (CAT) scanning in patient assessment and operative strategy and (7) the ultimate employability rate in survivors (78 percent). An historical review of the development of management principles based on operative experience in the military sector as well as other recent civilian literature also deserves consideration.

Adolescent↗
PubMed1979

Preoperative cell-mediated immune status of patients with malignant glial tumors.

The leukocyte adherence inhibition assay (LAI) was used to measure cell-mediated immunity in 26 patients with malignant glial neoplasms and in 41 control subjects. A significant inhibition of leukocyte adherence was observed in 21 out of 26 (80%) patients with malignant astrocytic gliomas in the presence of a 3M KC1 extract of glioma tissue compared to that of normal brain extract. Among the control group, no significant difference in the percentage of nonadherent leukocytes (NAL) was noted in the presence of either antigen. To study the specificity of the reaction, 3M KC1 extracts of meningioma, pituitary tumor, carcinoma of breast, carcinomas of lung, melanoma, brain, and heart tissues were employed as non-specific antigens. Such studies revealed significantly lower values of NAL. These data indicate that patients with malignant glial neoplasms manifest a cellularimmune response to glioma-associated antigens that can be measured by the tube LAI assay and that LAI assay may render additional useful information in the diagnostic and prognostic evaluation of malignant glial neoplasms.

Antigens, Neoplasm↗
PubMed1979

Influence of nitroprusside on cerebral pressure autoregulation.

The authors studied 10 cats to assess the question of abolition of cerebral autoregulation attendant on the use of nitroprusside for hypotensive anesthesia. After the establishment of stable base line parameters, a continuous infusion of sodium nitroprusside was begun in a dose sufficient to maintain a mean systemic arterial pressure of 65 mm Hg. Infusion was continued for incremental periods of 30 seconds to 10 minutes, increasing the time of infusion by 30 seconds after each subsequent trial. At 10 seconds after the cessation of nitroprusside administration, intravenous dopamine was infused to raise the systemic arterial pressure to a mean of 100 mm Hg, and the subsequent response in intracranial pressure was recorded in each instance. In no animal was a loss of cerebral autoregulation noted when the nitroprusside infusion was maintained for 3 minute or less. When the infusion was maintained for 4 minutes or longer, cerebral autoregulation was lost in each animal, and the length of time to return of cerebral autoregulation correlated with the duration of nitroprusside infusion. Sodium nitroprusside disturbs the integrity of cerebral pressure autoregulation, and the onset and extent of this disturbance is a dose-dependent phenomenon.

Animals↗
PubMed1979

Checkerboard visual evoked response in evaluation and management of pituitary tumors.

As a routine part of the evaluation of patients with pituitary tumor, visual evoked responses (VERs) to checkerboard pattern reversal were recorded from 83 patients with tomographically documented pituitary tumor. VER tests were correlated with examinations of visual acuity, color perception, and visual fields and with computerized tomographic scan evidence of suprasellar extension of the tumor. The purpose of the VER recording was to determine the presence of visual system compression by the tumor and thus contribute to the decision of whether surgery was necessary. Each of the patients who had suprasellar extension of the tumor sufficient to produce a visual field abnormality also had an abnormal VER. In addition, some patients with suprasellar extension had normal visual fields but abnormal visual evoked responses. Thus, the VER provided earlier evidence of suprasellar extension causing visual system compromise than did conventional visual tests.

Adenoma, Chromophobe↗
PubMed1979

Definition of cellular immune responses to brain antigens in human head trauma.

Cellular immune responses to brain antigens in patients with head injury were studied by applying the leukocyte adherence inhibition (LAI) assay. The investigation was conducted in three phases. 1) In the initial phase, evaluation of a series of 22 test and 25 control cases obtained at random during a 2- to 6-week time frame following a traumatic event indicated significant non-adherence of leukocytes (NAL) in 77% of the test group and 20% of the control group in the presence of brain antigen. 2) In a second phase, larger test population was divided into four groups of different posttraumatic intervals. This study measured NAL in the presence of normal heart of normal brain antigen. Assays revealed an initial significant NAL in the presence of both antigens; however, after the first week following injury the majority of cases manifested significant NAL only with brain antigen. These values of NAL persisted over a 6- to 8-week period. 3) As a final phase of investigation, analysis of a sequential series of assays in 12 patients over a 90-day period indicated significant NAL in the presence of brain antigen within the first week of injury, this was followed by a drop in NAL in most of the cases. Studies at 7 to 60 days posttrauma demonstrated significant NAL with brain antigen alone, with a subsequent drop by 90 days. These observations are interpreted to represent sensitization of leukocyte subgroups to brain proteins that are immunologically recognized following the traumatic event.

Antibody Formation↗