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Biomedical subjects

R Sawaya

Publications and source records attributed to R Sawaya.

At least 127 records · Page 7Linked to original sources
PubMed1989

Primary cerebral neuroblastoma (neurocytoma) in adults.

We report a case of a third ventricular neuroblastoma (neurocytoma) in a 66 year old man. A stereotactic needly biopsy was performed to obtain a tissue diagnosis and was followed by total resection. We elected not to give radiation or chemotherapy and to follow the patient closely with serial CT scans. Presently, 48 months postoperatively, the patient is free of tumor by head CT scan and able to live independently. We reviewed the literature of primary cerebral neuroblastomas/neurocytomas occurring in adults (greater than or equal to 15 years of age) and found 32 cases. Our patient is the oldest of this group with a mean age of 32 +/- 14 years (S.D.). The location of the 33 neoplasms was intraventricular in 17 cases (52%) and intraparenchymal in 16 cases. The male to female ratio was 2:1. Of the 17 patients having a minimal follow-up period of 5 months (mean 51 months), five developed recurrences after 5 to 144 months (mean 50 months) compared to 12 patients without recurrence after a 6- to 72-month follow-up period (mean 52 months). Recurrences occurred statistically significantly more often in parenchymal neuroblastomas/neurocytomas than in intraventricular tumor locations.

Aged↗
PubMed1989

Cerebral blood flow and metabolism in sleep.

A review is presented of the electrical activity of the brain and its global and regional blood flow and metabolism in the different stages of sleep and in wakefulness in animals and humans. During slow-wave sleep (SWS), the blood flow and metabolism of the brain decrease slightly below the level of wakefulness. During rapid eye movement the activity of the brain increases above that of SWS and sometimes above that of wakefulness. Some studies suggest that both at sleep onset and at arousal the brain stem-cerebellar complex (BSC) may be activated before the cortex and the right hemisphere before the left. Variation of hemispheric dominance seems to be a phenomenon of both wakefulness and sleep.

Brain↗
PubMed1988

Hyalinizing plasmacytic granulomatosis of the falx.

Computed tomography scan in a 43-year-old woman revealed a fusiform mass involving the falx. Pathological tissue removed at craniotomy revealed a hyalinizing plasmacytic granulomatosis composed of masses of lymphocytes, plasmacytes, and various sized islands of hyalinized fibers arranged in parallel and surrounded by multinucleated giant cells. Ultrastructurally, the hyalinized fibers consisted of electron-dense, amorphous deposits. After partial removal, irradiation, and steroid therapy, the lesion decreased considerably in size.

Adult↗
PubMed1988

Plasminogen activator activity and molecular weight patterns in human brain tumors.

Fresh human brain-tumor samples were assayed for their plasminogen activator (PA) content. Specific molecular weight patterns were identified for each of five common brain tumors and for normal brain, suggesting a cell-specific origin of the various PA forms. Malignant tumors contained higher PA activity and a larger number of molecular weight patterns than benign tumors, with the exception of acoustic neurinomas. Irradiated tumors contained lower PA activity than nonirradiated tumors. Finally, a slight but definite correlation between brain edema and PA activity was detected. The future role of brain-tumor PA's for diagnostic and therapeutic purposes is discussed.

Astrocytoma↗
PubMed1987

Immunohistochemical demonstration of alpha-1-proteinase inhibitor in brain tumors.

Using light microscopy and immunoperoxidase methods (PAP), the presence of alpha-1-proteinase inhibitor (API) was studied in seventeen brain tumors and four normal brain samples. The brain tumors included four glioblastomas, five low-grade gliomas, two metastatic lung carcinomas, two acoustic schwannomas, and four meningiomas. Normal brain displayed a finely granular intracytoplasmic staining confined to neuronal cells. Glial cells were negative for API. Fifteen of the 17 brain tumors were positive for API. Only two of five low-grade gliomas were negative for API. Glioblastoma and metastatic tumors exhibited the strongest positivity followed by acoustic neuroma, meningioma, and low-grade glioma. All positive samples exhibited finely granular intracytoplasmic API, and 50% exhibited extracellular API positivity. Metastatic and glioblastoma tumors demonstrated prominent extracellular API staining. Our results support the concept of a local production of API by brain tumors.

Blood Proteins↗
PubMed1987

Alpha-1-antitrypsin in human brain tumors.

This study was undertaken to confirm the presence of alpha-1-antitrypsin (alpha 1-AT) in human brain tumors and to attempt to elucidate its significance. Seventy-seven consecutive unselected patients with various brain tumors were entered in this study. The alpha 1-AT and alpha 2-macroglobulin contents of the tumor extracts were qualitatively assessed by Ouchterlony immunodiffusion techniques. Plasminogen activator (PA) activity was assayed electrophoretically on sodium dodecyl sulfate gels. The patients were were divided into two groups according to the positivity of their tumors to alpha 1-AT. Sixty-eight percent of the tumors were positive for alpha 1-AT, and all specimens were negative for alpha 2-macroglobulin. Clinical and biological parameters obtained in all study patients failed to show statistically significant differences between the two groups with the exception of PA activity (p = 0.001), the peritumoral edema as seen on computerized tomography, and the preoperative serum fibrinogen level. These three parameters were higher in the group with specimens positive to alpha 1-AT. This study supports the hypothesis that alpha 1-AT is produced primarily by tumor cells in proportion to the regional proteolytic and inflammatory activity, and may protect the tumor cells.

Brain Neoplasms↗
PubMed1986

The morphology and biologic behavior of human glioblastoma growing in nude mice.

Seven human glioblastomas (five small cell glioblastomas [SCG] and two anaplastic astrocytomas with giant cells [AA]) grown in serial passage in BALB/c nude mice and nude rats, were studied histologically and compared to human donor tumors. Four SCG maintained many basic features seen in donor tissue, i.e., cell type, tendency to produce micronecrotic palisading (MNP), high cellularity, numerous mitoses. Significant vascular proliferation was seen only in nude rat hosts of one of the SCG lines transplanted from mice at passage 11. Giant capillaries, cyst formation and hemorrhages were features of large (1.0 cm) heterotransplanted SCG. One SCG altered morphology from first passage, showing an adenoid pattern and mucinous change. Both AA preserved original tissue characteristics in initial passages. Later dedifferentiation occurred with small cells predominating. These small cells were larger and rounder than those of the SCG. Large AA showed central necrosis but rarely MNP, hemorrhages and focal inflammatory infiltrates.

Adult↗
PubMed1986

Intraoperative chemical hemostasis in neurosurgery.

Of the various electrical, mechanical, and chemical methods used in neurosurgical hemostasis, the chemical methods are the least well understood. In this review, data concerning seven modern chemical hemostatic agents are presented and special emphasis is placed on their neurosurgical applications. Overall, the general lack of fundamental knowledge concerning these agents at both the scientific and the clinical level was revealed by a relatively small number of publications over the past 4 decades. Several conclusions have been formulated to assist the neurosurgeon in the proper selection and use of these chemical agents. It is our belief that the use of chemical hemostatics in neurosurgery should be based on a thorough knowledge of their mechanism of action and should be supported by continuing laboratory and clinical research.

Aminocaproic Acid↗
PubMed1986

Successful laser-assisted excision of a metastatic midbrain tumor.

Metastatic lesions to the midbrain are rare. They are found in 1 to 3% of autopsy series of solitary brain metastases. The consensus of opinion in the current literature is that they are inoperable lesions and should be treated by radiation therapy alone. This is the first case report of a completely excised metastatic adenocarcinoma to the midbrain. The patient's clinical course has been stable, and there is no computed tomographic evidence of recurrence at 18 months follow-up.

Adenocarcinoma↗
PubMed1986

Antifibrinolytic therapy of experimentally grown malignant brain tumors.

This study was designed to evaluate the effect of an inhibitor of plasminogen activation on the growth of a human glioblastoma line grown in nude mice up to the seventh passage. The tumors produced plasminogen activators and showed histological characteristics similar to those of the original tumor. Three groups of mice were studied. Group A received 5% epsilon aminocaproic acid (EACA); Group B received 2.5% EACA; and Group C served as a control. There was no statistical difference among the three groups with regard to: 1) age at time of tumor transplantation; 2) the interval between implant and treatment; or 3) tumor volume at time of treatment. Blood measurements of EACA, performed in a limited number of animals, have shown that the drug at 5% concentration had reached toxic levels. Statistically significant differences between the three groups were noted in the following categories: 1) rate of tumor growth; 2) tumor volume at time of death, where Group A had smaller tumors than Group C; and 3) mean survival times of Groups A and B as compared to Group C. A statistically significant negative correlation was found between the rate of tumor growth and the length of survival of animals in Group C, while no correlation could be found for either Group A or B, indicating that the antifibrinolytic therapy modified this important biological variable. This study supports the hypothesis that the fibrinolytic system plays a role in the growth and development of malignant gliomas and that interference with the fibrinolytic system may retard the growth of these tumors grown in nude mice.

Aminocaproates↗
PubMed1986

Spontaneous cerebellar hematoma associated with chronic cerebellar stimulation. Case report.

A 24-year-old man developed a spontaneous cerebellar hematoma 5 years after the implantation of cerebellar electrodes. No vascular malformations were found either intraoperatively or radiographically. The histopathological findings of the cerebellar tissue obtained at biopsy from the region surrounding the electrodes support the hypothesis of a causal relationship between the spontaneous cerebellar hemorrhage and chronic cerebellar stimulation.

Adult↗
PubMed1985

Decerebrate posturing with the syndrome of inappropriate secretion of antidiuretic hormone.

Decerebrate and/or decorticate posturing have not yet been described as possible features of the syndrome of inappropriate secretion of antidiuretic hormone. Cerebral edema and loss of brain electrolytes are contributing factors resulting in altered excitability of the neural membrane. We describe a patient who, on the eighth day after a head injury, presented with decerebrate posturing, which coincided with the development of the syndrome of inappropriate secretion of antidiuretic hormone, and which rapidly reversed with the correction of the hyponatremia. We believe that the syndrome of inappropriate secretion of antidiuretic hormone should be included in the differential diagnosis of abnormal posturing in the head-injured patient.

Adult↗
PubMed1985

Plasma fibronectin in patients with brain tumors.

Fibronectin, a large molecular weight glycoprotein normally found on the surface of many cells, was measured in the plasma of 15 normal volunteers and 75 patients with various kinds of brain tumors or other kinds of neurological disorders. The mean plasma fibronectin in the control group was 253 micrograms/ml. Statistically significant elevations in fibronectin levels were found in patients with progressive high grade astrocytomas (mean = 413 micrograms/ml). The majority of patients with high grade astrocytomas in remission had normal levels of fibronectin (mean = 273 micrograms/ml). Elevations were noted in patients with low grade astrocytomas, meningiomas, and benign nonneoplastic neurological disorders. Plasma fibronectin may be useful diagnostically and therapeutically in identifying and managing some patients with high grade gliomas. However, of greater importance is the observation that fibronectin elevation is the result of a tumor-host interaction.

Astrocytoma↗
PubMed1985

Superior sagittal sinus thrombosis after closed head injury.

A case of superior sagittal sinus thrombosis after a closed head injury is presented along with a review of 11 other reported cases. Review of the literature indicates that this condition is rarely recognized and that further investigation is necessary to define the incidence, prognostic factors, and optimal therapy of this condition.

Adult↗