Cultured primate aortic smooth muscle cells express both the PDGF-A and PDGF-B genes but do not secrete mitogenic activity or dimeric platelet-derived growth factor protein

Proliferation of smooth muscle cells (SMC) in the arterial intima of man and experimental animals is important in the pathogenesis of atherosclerosis. Vascular SMC proliferation in vitro is stimulated by a number of agents, including the potent protein mitogen, platelet-derived growth factor (PDGF). Recent studies on rat arterial SMC indicate that these cells may, under certain circumstances, synthesize PDGF protein mitogens, suggesting that the regulation of SMC proliferation in vivo may have an autocrine or paracrine component. In this study we demonstrate that cultured nonhuman primate (baboon) aortic SMC transcribe both the PDGF-A and PDGF-B genes but do not secrete detectable mitogenic activity characteristic of native PDGF. The absence of this activity was not due to the presence in the cell conditioned medium of factors inhibitory for PDGF-mediated mitogenic activity. Metabolic labeling of the cells and immunoprecipitation with specific antibodies to human PDGF did not detect a dimeric (30 kDa) PDGF protein in either the intracellular or extracellular compartments, but instead identified PDGF-related proteins of molecular weight 12 kDa and 100 kDa. These data suggest the presence in vascular SMC of a mechanism regulating the translation of PDGF mRNA that may play an important role in the control of SMC proliferation in vivo.

Swelling of multicellular spheroids induced by hyperthermia

EMT6 multicellular spheroids invariably swell by 10 to 50 per cent after incubation at 43 to 45 degrees C for 1 h. Both scanning electron and optical microscopy reveal morphological alterations particularly in the outer region of the spheroids. While the control cells are contiguous to one another and tightly held to the spheroid body, the heated spheroids exhibit partially disrupted contacts among cells. Measurements of intercellular volume and water volume of spheroids with labelled water and inulin show that changes in the spheroid volume are not due to an increase in cell volume, but that they can be explained by a 60-100 per cent increase in the intercellular space within a spheroid. Continuous observation of individual spheroids heated to 43-45 degrees C shows loss of adhesion of cells in the outer region and even detachment of a few surface cells. This 'melting' of the spheroid surface appears to result from a disorder in the extracellular material. Treatment with cell swelling agents such as hypotonic solution, ouabain, excess extracellular potassium ions, or ionophore nigericin, K+/H+ exchanger, each separately causes the spheroids to swell at the control temperature. On the other hand, A23187, Ca2+ ionophore, causes shrinkage of the spheroids. Thus, under hyperthermia, the volume of spheroids increases due to the disruption in the cell organization in their outer region.

Hodgkin disease: contributions of chest CT in the initial staging evaluation

Chest radiographs and chest computed tomography (CT) scans were compared in 203 patients with newly diagnosed Hodgkin disease. The incidence of positive findings was tabulated from six intrathoracic lymph node groups, lung parenchyma, pericardium, pleura, and chest wall. The discordant cases were assessed to determine impact on clinical management. The CT scans provided additional evidence of disease involvement, ranging from 0% to 15% at each of the designated anatomic sites. Treatment was altered in 9.4% of all patients (19 of 203), including 13.8% (nine of 65) of those undergoing radiation therapy alone and 8.2% (ten of 122) of those undergoing combined-modality treatment. We conclude that routine chest CT examinations are valuable in the clinical management of those patients for whom radiation therapy is planned.

Propylthiouracil-induced hypothyroid hyperlipidemic chick: a model for clofibrate-induced toxicity

An animal model for clinically observed clofibrate (p-chlorophenoxy isobutyrate, CPIB)-induced toxicity has been tested. It is demonstrated that propylthiouracil-induced hypothyroid-hyperlipidemic chick develops severe toxic manifestations following clofibrate administration. Toxic symptoms are characterized by listlessness, drowziness, and extreme muscular weakness. This is associated with elevation of blood urea nitrogen, creatine phosphokinase, uric acid and glutamic oxaloacetic transaminase. Histological examination of muscle specimen from chicks exhibiting toxic syndrome showed degeneration and vacuolization of muscle fibers. The biochemical and histological changes observed are quite similar to those reported in clinical practice in some patients given clofibrate. It is suggested that this chick model could be used to investigate the biochemical basis of clofibrate toxicity.

Failure of exogenous prostaglandin to afford complete protection against acetaminophen-induced hepatotoxicity in the rat

The protective effect of 16, 16-dimethylprostaglandin E2 (dm-PGE2) against acetaminophen-induced hepatotoxicity was determined in the rat. The dm-PGE2 was administered at two dose levels both before and after acetaminophen administration. The hepatotoxicity was evaluated by a rise in serum transaminases 24 h after acetaminophen administration and by histological examination of liver preparations. The urinary acetaminophen and its metabolites were determined by high-pressure liquid chromatography. The results suggest that exogenous dm-PGE2 administration had a modest protection against acetaminophen-induced hepatotoxicity, in contrast to its well established cytoprotective effect against many noxious agents in the gastrointestinal tract. Prostaglandin treatment had little effect on acetaminophen metabolites excretion in the urine, suggesting that it did not affect the cytochrome P-450-dependent mixed-function oxidase drug-metabolizing enzyme system. The livers from dm-PGE2-acetaminophen-treated rats showed less advanced necrosis compared to those from saline-acetaminophen-treated rats. Whereas only 2 of 13 rats died in the prostaglandin-treated group, 4 of 13 rats died in the saline-treated group.

Subclavian venous stenosis. A complication of subclavian dialysis

Subclavian hemodialysis catheters are widely employed for temporary hemodialysis access, but there are few reports of serious complications. We report three cases in which the prolonged (greater than 15 days) use of subclavian dialysis catheters ipsilateral to the permanent vascular access was associated with the development of subclavian vein (SCV) stenosis three to six months after the temporary catheter was removed. In one case, the use of the permanent access was severely limited by massive arm edema. We conclude that, in addition to the usual complications of SCV cannulation, long-term use of SCV hemodialysis catheters can be associated with major late obstructive complications that may compromise permanent vascular access. We recommend that, wherever possible, temporary dialysis catheters and other subclavian lines be placed contralateral to the permanent vascular access site in patients undergoing hemodialysis.

Acquired renal cystic disease and renal neoplasms in hemodialysis patients

Noninvasive imaging studies were performed on 26 patients undergoing chronic hemodialysis. We found cysts in 46% of patients and neoplasms in 7.7%. The cysts were relatively easy to detect. However, the neoplasms were very difficult to detect; this problem has been described before in the literature. The natural history of acquired cystic disease and neoplasms in hemodialysis patients is largely unknown. A review of the problems associated with the imaging and management of these patients is included.

Sarcoidlike granulomas as an early manifestation of Whipple's disease

Whipple's disease is often accompanied by a long, preintestinal phase of vague symptoms, such as weight loss, fever, and migratory arthralgia, which may delay diagnosis and proper treatment. We report a patient who presented with sarcoidlike granulomas in the lung 1.5 yr before the development of gastrointestinal symptoms. He was treated with prednisone and his lung lesions improved dramatically. However, steroids could not be discontinued until the diagnosis of Whipple's disease was made and he was started on antibiotic treatment. Whipple's disease was diagnosed from a small intestinal biopsy specimen by electron microscopic demonstration of characteristic bacillary bodies. Liver biopsy specimens also demonstrated a few Kupffer cells containing degenerative bacillary bodies. Based on this case and other reported cases of Whipple's disease with sarcoidlike lesions in various organs, we suggest that sarcoidlike tissue reaction can be an early manifestation of Whipple's disease, recognition of which may have practical value in facilitating an early diagnosis and treatment.

Effects of propylthiouracil on urinary metabolites of cyclophosphamide in rats

Our previous studies have shown a protective effect of propylthiouracil (PTU) pretreatment against the toxicity of cyclophosphamide (CP). The present study was undertaken to investigate the mechanism of the PTU protection. CP is metabolized by the cytochrome P-450 drug-metabolizing enzyme system in the liver to alkylating metabolites, to active antineoplastic agents, and to acrolein, the most toxic and least antineoplastic metabolite. Measurements of CP metabolites in blood and urine during a 4-hr i.v. infusion of CP (50 mg/kg body weight/hr) showed urinary acrolein excretion to be 2.5 times higher in control rats as compared to PTU-treated rats. Since it has been reported that urinary acrolein levels are directly related to the frequency and severity of hemorrhagic cystitis, it is concluded from our observations that prevention of hemorrhagic cystitis is probably mediated by the PTU effect on lowering urinary acrolein concentration and excretion. Serum alkylating activity was significantly higher in the PTU-pretreated rats, which may enhance the antineoplastic potential of CP.

Hepatotoxicity and metabolism of acetaminophen in male and female rats

This present study was designed to assess the role of metabolic and pharmacokinetic factors in the lower susceptibility of female rats compared to male rats to xenobiotics metabolized by the cytochrome P-450-dependent mixed-function oxidase (MFO) system. Adult intact male and female Sprague-Dawley rats were administered labeled acetaminophen (1 g/kg body weight + 5 microCi [3H]acetaminophen) after an overnight fast. They were bled and killed at 0.5, 1, 2, 3, 6, 12, 24, and 36 h after drug administration. The percentage of [3H]acetaminophen radioactivity remaining in blood, liver, GI tract, and excreted in the urine was determined at all time intervals. Plasma prothrombin time and serum transaminases were determined as indices of hepatotoxicity. Hepatic GSH and glycogen were assayed. Total urinary acetaminophen and its metabolites and the molar percent of various metabolites excreted during the first 6 h were determined. Castrated male and ovariectomized female rats and their respective controls were also given acetaminophen (APAP) and were killed 24 h later to determine hepatotoxicity. The extent of hepatic damage in the intact male rats was greater and appeared sooner than in the female rats. Hepatic GSH and glycogen were depleted earlier in female rats. The percent of the administered dose excreted in the urine during the first 6 h was 17.5 for the male rat versus 24.5 for the female rat. While the APAP glucuronide conjugate concentration was significantly higher, the APAP sulfate conjugate concentration was lower in the female than it was in the male rat. Although peak radioactivity in serum was reached by 30 min in both male and female rats, suggesting quick intestinal absorption, it was significantly higher in female rats and was associated with decreased intestinal and hepatic levels and increased urinary excretion when compared to male rats. While castration of male rats decreased susceptibility to hepatotoxicity, ovariectomy of female rats tended to increase susceptibility to hepatotoxicity in comparison to their respective controls. Our data suggest that aside from the reported sex differences in the cytochrome P-450-dependent MFO enzymes, there are significant differences in GSH utilization. There are also significant changes in glucuronidation and sulfation pathways, as well as in the pharmacokinetics of acetaminophen, which tend to protect female rats against acetaminophen hepatotoxicity.

Prevention of acetaminophen hepatotoxicity by propylthiouracil in the glutathione depleted rat

This study was designed to investigate the protective effect of PTU pretreatment against acetaminophen hepatotoxicity in rats whose hepatic GSH had been depleted by prior diethylmaleate (DEM) administration. A single injection of DEM depleted hepatic GSH showing lowest level after 90 min in both control and PTU pretreated rats. Triple injection schedule kept the hepatic GSH concentrations consistently very low up to 6 hr. Whereas a toxic dose of acetaminophen administration did not effect SGOT and SGPT levels after 30 hr in PTU pretreated rats given either a single or multiple injections of DEM, the same dose of acetaminophen in the control rats raised these transaminases to a very high level. High activity of transaminases was associated with significant histological hepatic damage. Our results suggest that PTU pretreatment affords significant protection against acetaminophen hepatotoxicity even under conditions when hepatic GSH concentrations have been significantly depleted prior to acetaminophen administration.

Colonic lymphoma producing alpha-chain disease protein

Alpha-chain disease with involvement of small intestine-resulting in characteristic villus atrophy and malabsorption has not been reported in this country. We studied a 57-yr-old male who presented with a polypoid tumor of the hepatic flexure of the colon. There was no evidence of malabsorption as manifested by a normal fat balance, serum carotene, and D-xylose absorption studies and the small bowel biopsy did not show villus atrophy. The tumor in the colon was surgically removed and diagnosed as a malignant lymphoma of lymphocytic type. Tumor tissue infiltrated in the mesentery could not be excised. Alpha-chain disease protein was demonstrated in serum and urine, and also in tumor tissue by immunoperoxidase techniques. The alpha-chain disease protein was further purified and classified as subclass 1. The patient had a good clinical response to cyclophosphamide and prednisone, but still has intraabdominal lymphoma with gastric involvement, and his serum alpha-chain protein persists. This case report may represent a distinct variant of alpha-chain disease.

Heat stroke. Report of three fatal cases with emphasis on findings in skeletal muscle

Three fatal cases of heat stroke were encountered in the central New York area over a two-month period. Although in each instance one or more predisposing factors were identified, exertion clearly played a role in its development in only one case. In addition to laboratory and postmortem findings indicative of dysfunction of many organ systems, there was morphological evidence of widespread damage to skeletal muscle.

Effects of chronic beta-glycerophosphate administration on growth rate and on serum, liver and bile lipid composition in the squirrel monkey--a toxicity study

Oral administration of beta-glycerophosphate lowers the lithogenic index in patients with cholesterol gallstones and is considered to have potential for dissolving them. A high dose of beta-glycerphosphate was fed to primates (Squirrel monkeys) for a period of 15 months. There were no adverse effects on body weight, hematological or liver function tests. Serum, liver and bile lipids concentrations were not significantly changed, although serum and hepatic bile phospholipids were increased. Organ weights expressed as percent of body weight were not changed except for a slight increase in kidney weight. Histological examination of liver and kidneys did not reveal any pathological findings. Slight renal hypertrophy was attributed to the sodium content of beta-glycerophosphate.