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Biomedical subjects

M Oz

Publications and source records attributed to M Oz.

9 recordsLinked to original sources
PubMed1991

Malignant carcinoid tumor metastatic to the dura mater simulating a meningioma.

A 50-year-old man, transferred from another hospital, was admitted because of adult onset seizures. Nine months earlier, he had undergone an esophagogastrectomy; the lesion was confirmed to be a carcinoid tumor. Laboratory tests, chest x-rays, and electrocardiogram were normal. A second liver and spleen scan was performed. A computed tomographic scan revealed a well-circumscribed homogeneous enhancement of a lesion in the left frontal superficial area. On the 10th day, the patient underwent a left frontal parietal craniotomy. Postoperatively, he manifested no residual neurological deficits and was discharged on the 6th postoperative day. A week later, he was readmitted for treatment of aphasia and right hemiparesis; he was treated and discharged. The patient survived 16 more months. The occurrence of central nervous system metastasis from carcinoid tumor is rare. This tumor resembled, in many respects, a parasagittal meningioma. Radiological findings on the computed tomographic scan were typical of these tumors. This patient was diagnosed as having metastatic disease just 9 months after the diagnosis of the primary tumor and 13 months from the onset of any symptoms. This is a short period of time compared with that reported in other cases.

Brain Neoplasms↗
PubMed1991

Decrease in the size of tetanic responses produced by nitrendipine or by extracellular calcium ion removal without blocking twitches or action potentials in skeletal muscle.

The effects of removing extracellular Ca++ ions or of adding the organic calcium channel antagonist, nitrendipine, were tested on twitches and tetani (100 Hz for 2 sec) in frog toe muscles. Under conditions that did not reduce or that potentiated twitches, both procedures reduced the size of the tetanic responses. This depression was seen as an inability to maintain the maximum tetanic tension for more than 0.5 sec. Intracellular microelectrode recordings showed that the muscle fibers were depolarized (mean about 23 mV) during the stimulus train and the fiber only slowly repolarized after the train. The latter effect is the "late negative afterpotential" and it is produced by the accumulation of K+ ions in the t-tubules during the action potential train. Neither the depolarization nor the late negative afterpotentials were decreased in amplitude by nitrendipine. These results indicate that the voltage-sensitive, slow Ca++ channels are opened by the accumulation of K+ ions in the t-tubules during the tetanus and that the Ca++ ions entering via these channels are required to maintain the full strength of the tetanic contraction. It is suggested that this is a function of these Ca++ channels concentrated in the t-tubules of skeletal muscle fibers.

Action Potentials↗
PubMed1989

Replacement of the abdominal aorta with a sutureless intraluminal ringed prosthesis.

To evaluate our experience with sutureless intraluminal ringed grafts in the abdominal aorta, we reviewed all patients who were managed with this device from 1980 to 1987. Thirty-one patients were identified with a mean follow-up time of 41 months. Three patients had suprarenal aneurysms and four had ruptured abdominal aneurysms. Average tube graft insertion time was 17 minutes and required 0.9 units of transfused blood. There were two postoperative deaths (6 percent), both secondary to myocardial infarction. None of the patients with ruptured or suprarenal aneurysms died. No patients had permanent renal or neurologic deficits, and no instances of postoperative bleeding, wound infection, pseudoaneurysm formation, or graft migration were encountered. The sutureless intraluminal graft can be implanted easily and quickly and is safe for use in the abdominal aorta. It is particularly helpful in the management of suprarenal or ruptured abdominal aneurysms, in which speed is important, and in effecting technically difficult anastomoses to friable aortic tissue.

Adult↗
PubMed1986

Esophagogastrectomy. Successful palliation for esophageal carcinoma.

Although esophagogastrectomy offers the best chance for cure and alleviation of dysphagia in the treatment of esophageal carcinoma, the operative mortality and morbidity can be prohibitively high. To investigate means for reducing the rate of surgical complication, a study was made of a six-year series of 36 procedures involving 32 esophagogastrostomies and four colon interpositions. Patient survival rates were 60 percent at one year, 40 percent at two years, and 9 percent at five years with a mean survival of 22 months. Histology of the tumor did not significantly affect prognosis. The three operative mortalities were caused by pulmonary insufficiency in one overhydrated patient, and coagulopathy in two alcoholic patients with underlying liver disease. Anastomotic leakage, the precipitating factor for the majority of operative mortalities in the recent literature, occurred in one non-fatal case. This low incidence is linked to the implementation of steps to maximize blood supply and minimize tension on the anastomosis line. Anastomotic stricture was seen and easily dilated in three patients. The five cases of intra-esophageal tumor recurrence which occurred despite tumor-free margins may have been avoided by more extensive resection.

Adenocarcinoma↗