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Biomedical subjects

S I Schwartz

Publications and source records attributed to S I Schwartz.

At least 19 recordsLinked to original sources
PubMed1991

Insulin inhibits apolipoprotein B secretion in isolated human hepatocytes.

The effect of insulin on apolipoprotein (apo) B secretion was investigated in human hepatocytes. Freshly isolated hepatocytes, prepared by collagenase dispersion of liver specimens, were incubated in serum-free media in the absence and presence of 100 nmol/L insulin for 2 hours. The media was then assayed for apo B content by radioimmunoassay. In hepatocytes incubated without insulin, the secretion of apo B (relative to human low-density lipoprotein [LDL]) was 125 +/- 37 ng/10(6) cells/2 hours. In the presence of insulin, apo B secretion was reduced to 83 +/- 29 ng/10(6) cells/2 hours (34% inhibition, P less than .05). These results using human hepatocytes are consistent with previous data from our laboratory describing insulin-dependent inhibition of apo B secretion in primary cultures of rat hepatocytes and studies by others employing the human-derived hepatoma cell line, Hep G2. We conclude that human hepatic apo B secretion is under insulin control. The role of more chronic insulin exposure requires further investigation.

Apolipoproteins B↗
PubMed1991

Hepatic adenoma and focal nodular hyperplasia.

Hepatic adenoma and focal nodular hyperplasia are benign lesions of the liver. The incidence of these conditions has been increasing since 1970. Hepatic adenoma primarily affects young women of childbearing age who have a long history of using oral contraceptives, while focal nodular hyperplasia has a wider age distribution and is not associated with the use of oral contraceptives. The most extensive complication of hepatic adenoma is intratumoral or intraperitoneal hemorrhage, which occurs in 50 to 60 per cent of patients. Patients with focal nodular hyperplasia are usually asymptomatic and rarely experience complications. Hepatic adenoma is distinct from focal nodular hyperplasia both in its clinical behavior and its pathologic features; the two can usually be differentiated radiographically using a combination of radionuclide scanning and angiography. There is a proved association between the use of oral contraceptives and the development of hepatic adenoma; the longer the duration of oral contraceptive use, the more the risk of having hepatic adenoma develop. In addition, users of oral contraceptives who have hepatic adenoma develop are likely to have larger tumors and higher rates of bleeding and rupture than nonusers who have hepatic adenoma develop. Although hepatic adenomas may regress after discontinuation of oral contraceptive use, this is not a consistent finding. In addition, it has now been demonstrated that hepatic adenomas do undergo malignant transformation and that this can be detected by measuring the alpha-fetoprotein level. Focal nodular hyperplasia may be a precursor for fibrolamellar hepatocellular carcinoma. Elective resection of hepatic adenoma has a mortality rate of less than 1 per cent, while the mortality rate with free rupture is 5 to 10 per cent. Because of the relative safety of elective versus emergency resection and the potential for malignant change, the treatment of choice for hepatic adenoma is surgical resection.

Adenocarcinoma↗
PubMed1991

Carcinoma of the parathyroid gland: a 30-year experience.

Eleven patients with parathyroid carcinoma and 186 patients with parathyroid adenoma were seen between 1958 and 1990. Significant differences (p less than 0.01) were found between the two groups in calcium and parathormone levels, lesion size, presence of palpable mass, and severity of clinical presentation. Initial operative management consisted of parathyroidectomy alone in three patients, all of whom experienced recurrence of disease. Of the eight patients who underwent aggressive surgical management (parathyroidectomy and resection of thyroid or thymus), only one experienced recurrence. Three of the four patients with recurrence underwent multiple thoracic and cervical procedures for control of disease; one patient was treated with medical therapy alone. The mean survival in the surgical group was 17 years; the patient treated with medical therapy survived 10 years. In all four patients, however, treatment was palliative rather than curative. We conclude that patients with primary hyperparathyroidism characterized by markedly elevated serum calcium and parathormone, palpable mass, and severe clinical presentation should be suspected of harboring a parathyroid carcinoma. An aggressive initial surgical approach was considered in these patients. This experience emphasizes the importance of aggressive surgical extirpation in reducing disease recurrence and also for palliation and prolongation of life when recurrence does occur.

Adenoma↗
PubMed1990

Hepatic resection.

The current performance and applicability of elective hepatic resection represents an impressive evolution. From removal of tumor-bearing, ill-defined portions of the liver, which is always threatened by the inability to control bleeding, surgery of the liver has progressed to hemostatically controlled dissection of anatomically defined portions of the organ. Accompanying the series of technical refinements that have markedly reduced the mortality and morbidity rates associated with the procedure, there has been an expansion of the indications for hepatic resection.

Hepatectomy↗
PubMed1990

Recurrent acute pancreatitis caused by ampullary villous adenoma.

Neoplastic lesions of the ampulla of Vater are a rare cause of acute and recurrent pancreatitis. We have recently had the privilege of studying a 58-year-old woman who presented with recurrent pancreatitis. At endoscopic retrograde pancreatography, a mucosal abnormality of the ampulla of Vater was noted and documented to be a villous adenoma. It was resected surgically and the patient has been symptom free. This report documents the ninth patient in the English literature with pancreatitis secondary to a benign neoplasm of the ampulla of Vater. Six of the nine patients have been male. They have ranged in age from 42 to 68 years. Approximately 30% of villous adenomas of the duodenum contain foci of invasive or in situ carcinoma. Villous adenomas of the ampulla of Vater require aggressive therapy. Further, it has been noted that a number of patients with small intestinal neoplasms have concomitant large-bowel polyps.

Acute Disease↗
PubMed1989

Diagnostic and therapeutic approaches to pyogenic abscess of the liver.

A review was conducted of 33 patients with pyogenic hepatic abscesses seen during the past seven years to evaluate the effect of roentgenologic refinements on diagnosis and therapy. Cause, bacterial infection and clinical manifestations were determined. An ultrasonogram was positive in 27 of 29 patients; computed tomographic scan was diagnostic in 20 of 23 patients, and radionuclide studies were positive in eight of 13 patients. Abscesses were confined to the right lobe in 19 patients, to the left lobe in six and were diffuse in eight. In the group of patients with abscesses developing from a biliary route, one patient was successfully managed by roentgenologically controlled drainage while three others required subsequent surgical drainage. Five of seven patients in the biliary route category who were treated with primary surgical drainage were permanently cured. Twelve patients had an abscess emanating from the portal route. In five of these, drainage under roentgenologic control was successful. Two patients upon whom the procedure failed subsequently underwent drainage at operation. Five had primary surgical drainage, and two of these died. All nine patients with post-traumatic, cryptogenic abscesses or an abscess evolving from an arterial route were successfully drained surgically. Three patients with multiple or diffuse abscesses were successfully treated by primary hepatic resection. Refined roentgenologic techniques established the diagnosis of pyogenic abscess in almost all instances. Roentgenologically controlled drainage may be therapeutic in some patients, but surgical drainage remains the standard. Resection has been used as primary treatment in selected patients.

Adolescent↗
PubMed1987

Cavernous hemangioma of the liver. A single institution report of 16 resections.

Over the past 27 years cavernous hemangioma of the liver has been diagnosed in 12 nonoperated patients and in 16 patients who had resection of the lesion at Strong Memorial Hospital. In almost all patients the diagnosis was suggested by an imaging procedure. In the 12 nonoperated patients the average size of the tumor was 4.7 cm (range: 3-8 cm). No problems related to the tumor occurred during the follow-up period. The average size of the resected lesion was 10 cm (range: 4-32 cm). The usual indication for resection was pain, mass, or a combination of these manifestations. Five lobectomies, five left lateral segmentectomies, two trisegmentectomies, two segmentectomies, and two enucleations were performed. There were no postoperative deaths. Review of the literature indicates that although rapid growth of the lesion occurred during pregnancy in one patient, the effects of pregnancy or contraceptive drugs on growth are inconsistent. Spontaneous rupture occurs infrequently, and the potential for rupture should not constitute an indication for resection, which should be performed selectively. Intraoperative blood loss may be appreciable, but a mortality rate near 0% has been reported in all institutional series.

Adult↗
PubMed1986

Pulmonary platelet trapping in Escherichia coli endotoxin-injected dogs treated with methylprednisolone, ibuprofen and naloxone.

Adult respiratory distress syndrome (ARDS) is a common and serious complication of septic shock. Pulmonary trapping of platelets (PPT) and leukocytes, and release of vasoactive and toxic substances such as prostaglandins, lysozymes and oxygen-radicals have been implicated as mediators of the lung injury. beta-Endorphin is regarded as one of the substances released during shock, and has been shown to cause cell damage similar to that seen with endotoxin, and also PPT. We recently reported that combined treatment with methylprednisolone, ibuprofen and naloxone significantly increased lasting survival in an LD100 canine endotoxin shock model. In the present study the effects of these drugs in various combinations were evaluated as regards blood pressure, hematocrit, peripheral platelet and leukocyte counts, intestinal damage and PPT in the same model. The effects of combined treatment were significantly decreased PPT, rise in blood pressure and abolition of bloody diarrhea. We concluded that ibuprofen and naloxone have additive action and that methylprednisolone has no effect on PPT.

Animals↗
PubMed1986

Increased survival with calcium antagonists in antibiotic-treated bacteremia.

This study was done to test the effectiveness of calcium antagonists on survival in a bacteremic model. Swiss albino mice were injected intraperitoneally with live Escherichia coli at an LD90 dose. When antibiotic treatment was delayed for 3 hr after E coli challenge, there was a mortality range of 30-50% for the gentamicin-treated mice and 40-60% for the cefoxitin-treated mice. A calcium antagonist, either nifedipine or verapamil, was added to this model in different dosages and at different time intervals. Nifedipine yielded a significantly lower mortality both with gentamicin and with cefoxitin. Verapamil did not affect mortality with cefoxitin but did improve survival with gentamicin. Effective dosages occur within a narrow range. The results are encouraging and call for further studies with calcium antagonists to ascertain their prospective usefulness as additives to septic shock treatment.

Animals↗
PubMed1985

Assessment of treatment of intrahepatic malignancies using chemotherapy via an implantable pump.

Thirty patients in whom an implantable pump was used for hepatic arterial perfusion of chemotherapeutic agents to treat hepatic malignancy were evaluated. Three patients with primary hepatocellular carcinoma demonstrated less than 50% reduction in tumor size. One patient with metastatic gastric carcinoma and one patient with metastatic islet cell carcinoma also showed a decrease of less than 50% in the size of the tumor mass. Among the 25 patients with metastatic carcinoma from the colon or rectum, 23 had elevated carcinoembryonic antigen (CEA) levels before surgery and 75% of these revealed a reduction of at least 50%. Only three of 20 patients followed with sequential imaging studies showed a 50% decrease in the size of the tumor mass. No increase in the duration of survival could be defined when the treated patients were compared with 13 patients who had not received chemotherapy. The pump functioned well in all patients, but 77% showed signs of toxicity. This experience, coupled with a review of the literature, suggests that the procedure should be regarded as experimental and should not be applied liberally until a definite benefit can be demonstrated.

Adenoma, Islet Cell↗
PubMed1985

Primary lymphoma of the gastrointestinal tract.

Forty-six instances of gastrointestinal tract lymphoma are reviewed with attention to clinical features, diagnostic studies, surgical approach and adjuvant therapy. Gastrointestinal tract lymphoma may be present at any age in individuals with pain, abdominal mass or other abdominal findings, and all ulcers and other endoscopically accessible lesions require biopsy, without regard for roentgenologic or endoscopic appearance of benignity. Resection is recommended when cure is possible; adjunctive therapy is regarded as beneficial. There is a good prognosis for those patients surviving two to three years beyond diagnosis.

Actuarial Analysis↗
PubMed1985

Pulmonary platelet trapping induced by beta-endorphin injection in the cerebrospinal fluid in dogs.

The effect of beta-endorphin injected into either the lateral ventricle or the cisterna magna on blood pressure, heart rate, peripheral platelet and leukocyte counts, hematocrit levels, catecholamines, and pulmonary platelet trapping was studied. The effect of endotoxin on the endogenous opiocortin system was also investigated. Injection of beta-endorphin caused a significant decrease in blood pressure, bradycardia, and pulmonary platelet trapping. beta-Endorphin had no effect on peripheral platelet and leukocyte counts, catecholamines, or hematocrit levels. Endotoxin shock caused a marked rise in circulating beta-endorphin and a decrease in cerebrospinal fluid beta-endorphin. Our results confirm that endotoxin shock activates the opiocortin system, and we suggest that the endorphins may participate in the evolution of the lung injury seen in septic shock.

Animals↗
PubMed1985

Effect of high dose corticosteroids alone or combined with other drugs on survival in septic shock.

The effect of high dose corticosteroids on survival has been studied in a limited number of canine septic shock models which are reviewed in this presentation. Following injection of live bacteria neither methylprednisolone, nor gentamicin but a combination improved survival. Methylprednisolone increased survival following a slow but not a bolus infusion of endotoxin. In a recent study the effects of short term treatment with methylprednisolone, naloxone and ibuprofen were studied in endotoxin shock. All control animals died within 36 hours. Five of 9 dogs receiving the combination methylprednisolone, naloxone and ibuprofen were permanent survivors. The combined treatment with methylprednisolone and ibuprofen also increased survival. Dogs treated with methylprednisolone alone did not differ significantly from controls. It is concluded that methylprednisolone alone has no significant effect on survival in septic shock, but seems to be an important therapeutic factor to achieve increased survival.

Animals↗
PubMed1985

Verapamil improves cardiac function and increases survival in canine E. coli endotoxin shock.

The effects of verapamil, a calcium antagonist, on survival and on hemodynamic and metabolic parameters were studied in canines administered E. coli endotoxin. Shams, endotoxin controls, and endotoxin-shocked dogs treated with a 4-hour infusion of verapamil were studied. The animals were anesthetized, catheters and endotracheal tube were inserted, and an IV infusion was started after administration of endotoxin. All dogs were kept on a respirator for 4 hours while measurements were taken; they were then extubated and returned to their cages. Survival was considered permanent by 7 days. Eight of 13 treated dogs survived, in contrast with only one of 14 controls. Treated dogs had significantly higher cardiac index (4.64 vs 3.62 L/min/m2), pulmonary artery pressure (16 vs 13 mmHg), and left ventricular stroke work (44.3 vs 29.7 gm/m2 beat), and significantly lower heart rate and systemic vascular resistance at 4 hours. Serum glucose, acid phosphatase, pH, and Hct were also significantly improved by verapamil treatment.

Acid Phosphatase↗
PubMed1979

Effect of sphincteroplasty on gallbladder function and bile composition.

The effect of sphincteroplasty on bile concentration and composition and on gallbladder function was investigated in the dog. Gallbladder and hepatic bile samples were analyzed for cholesterol, phospholipid (lecithin), bile salt concentration and individual bile salt content. Motor function was studied by cholecystokinin-cholecystography with changes in gallbladder volume computed from the radiographs. All bile samples were cultured and at the conclusion of the experiments, the gallbladders were histologically examined. Sphincteroplasty did not alter biliary cholesterol concentration but the concentration of lecithin and bile salts decreased in gallbladder bile and increased in hepatic bile (p less than .001). These changes depict a trend toward greater lithogenicity for gallbladder bile and lesser lithogenicity for hepatic bile. Postoperative analysis of individual bile salts in gallbladder bile showed an increase in monohydroxy and dihydroxy bile salts and a decrease in trihydroxy bile salts (p less than .001). This tendency has been shown to be conducive to gallstone formation. The concentrating ability of the gallbladder was partially eliminated by sphincteroplasty but gallbladder filling and motor response to stimulation by cholecystokinin was not affected. All gallbladders demonstrated histologic changes of chronic inflammation and all developed a significant bacterial flora following sphincteroplasty. It is concluded that cholecystectomy should always be performed following transduodenal sphincteroplasty not because of any resultant abnormality of motor function, as has previously been held, but because of the resultant abnormality of gallbladder pathophysiology.

Ampulla of Vater↗