Caco-2 cell disaccharidase activities are unaffected by gestational hormones

We previously reported that lactose handling was significantly improved during late-phase pregnancy in women with a genetically determined adult-type hypolactasia. However, the adaptive mechanisms underlying the enhanced lactose digestion during pregnancy are not clear. Progesterone therapy has been associated in animals with increased intestinal lactase activity. To investigate the potential role of progesterone and estrogen as modulators of human lactase activity during pregnancy, we employed the human-derived intestinal epithelial Caco-2 cell line. Measurements of lactase and sucrase activities were performed in parallel with DNA content in progesterone- and estrogen-treated cells after 5, 10, and 30 days of confluency. Caco-2 monolayer DNA content was observed to increase with duration of culture to an equivalent extent in both hormone-treated and control cultures. Lactase and sucrase activities were similarly unaltered by incubation with either progesterone or estrogen, at any time point tested. These data demonstrate that gestational hormones do not influence intestinal cell number nor disaccharidase activity in Caco-2 cells, at the doses tested. Although these studies were carried out in a malignant cell line, our data suggest that the improved lactose handling observed during pregnancy is probably related to prolonged intestinal transit.

Insulin modulation of newly synthesized apolipoproteins B-100 and B-48 in human fetal intestine: gene expression and mRNA editing are not involved

We investigated insulin's effect on intestinal lipid, transport and, particularly, the biogenesis of apolipoproteins crucial to lipoprotein secretion. Adding insulin (3 mU) to the serum-free medium of cultured jejunal explants from human fetuses (17-20 weeks) reduced triglyceride and chylomicron production and inhibited apo B-48 and apo B-100 secretion. When apo B mRNA was assayed by RT-PCR and its editing by primer extension, no change was detectable following the addition of insulin. HDL lipid content, apo A-1 synthesis and RNA level were unaffected by insulin. Collectively, these results suggest that the insulin-stimulated decline in intestinal chylomicron output may involve apo B co- or post-translational modifications.

Formularies in integrated health systems: Sharp HealthCare

Formulary management implications are described for a California health system comprising 7 hospitals, 4 skilled-nursing centers, 22 medical clinics, 8 urgent care facilities, and a health maintenance organization. Sharp HealthCare serves nearly one million people in the San Diego area. A single institutional care division (ICD) pharmacy service has been created under the guidance of a steering committee comprising a pharmacy operations coordinator and a staff pharmacist from each site, the system pharmacy director, the system senior pharmacy information systems specialist, and the system senior clinical pharmacy specialist. Operations at each site are overseen by an operations coordinator instead of a pharmacy director. Functional teams reporting to the steering committee are standardized pharmacy processes, including formulary management; this is particularly important because the ICD has pharmacists and nurse per diem pools. Until 1995, formularies were independently managed at each site. Now, one system formulary is being developed. Standard policies and procedures, a nonformulary drug request form, and a monograph format have been completed. The hospitals' autonomous medical staffs have thus far elected to retain individual pharmacy and therapeutics (P&T) committees but approved a revamped formulary review process and system-wide P&T subcommittees. The computer system is being enhanced so that pharmacists will have access to applicable P&T committee-approved guidelines for drug use. Since vendors were advised that the system is establishing one formulary, Sharp has been able in some cases to achieve better pricing than it previously could through its purchasing group.

Purification and characterization of placental heparanase and its expression by cultured cytotrophoblasts

The role of different extracellular matrix (ECM)-degrading enzymes in the normal functioning of the placenta is well documented. Heparan sulphate proteoglycan (HSPG) is an integral constituent of the placental and decidual ECM. Because this proteoglycan specifically interacts with various macromolecules in the ECM, its degradation may disassemble the matrix. Hence, in the case of the placenta, this may facilitate normal placentation and trophoblast invasion. Crude placental specimens were collected from first and third trimester placentas. Heparanase (endo-beta-glucuronidase) was isolated and purified by ammonium sulphate precipitation followed by sequential chromatographies on carboxymethyl-, heparin- and ConA-Sepharose columns. The placental enzyme was further characterized for its molecular weight and specific inhibition by heparin, and was shown to resemble heparanase expressed by highly metastatic tumor cells and activated cells of the immune system. In order to locate the source of heparanase activity in the placenta, primary cytotrophoblast cultures were established. Intact cells, as well as conditioned medium and cell lysates, were analysed for heparanase activity using metabolically sulphate-labelled ECM as a natural substrate. Heparanase was highly active in lysates of cytotrophoblasts. This activity was also expressed by intact cytotrophoblasts seeded on ECM, but no activity could be detected in the culture medium. Incubation of the cytotrophoblasts in contact with ECM resulted in release of ECM-bound basic fibroblast growth factor (bFGF). We propose that the cytotrophoblastic heparanase facilitates placentation, through cytotrophoblast extravasation and localized neovascularization.

Gene therapy: socioeconomic and ethical issues. A roundtable discussion

Gene therapy research has the potential to revolutionize the way in which many human diseases are treated. Despite its enormous potential, roundtable panelists concluded that the field needs time to mature scientifically without pressure to develop a marketable therapeutic product. In addition, health care decision makers, physicians, and the lay public need to be educated on the future medical, economic, and ethical ramifications of gene therapy.

Lipid processing and lipoprotein synthesis by the developing human fetal colon

Despite significant progress in the elucidation of the ontogeny of gastrointestinal function, little attention has been given to colonic lipid processing during development. The major purpose of this study was to explore the intracellular phase of fat absorption, lipid synthesis, and secretion in the human fetal colon compared with the jejunum originating from the same fetuses. The synthesis of lipids and major apolipoproteins was examined using cultured fetal colonic explants incubated with [14C]oleic acid and [36S]methionine, respectively. Fetal colonic explants demonstrated substantial ability to incorporate [14C]oleic acid (dpm/mg protein) into phospholipids (48,743 +/- 4,783), triglycerides (25,687 +/- 2,469), and cholesteryl esters (6,751 +/- 1,227). The total amount of radiolabeled lipids was much higher within the tissue (87,472 +/- 9,142) than in the medium (51,916 +/- 4,970), indicating a limited capacity of the fetal colon to export newly synthesized lipids. The limited colonic lipid secretory process was even more evident when compared with homologous fetal jejunal de novo synthesized lipids in tissue (133,975 +/- 13,836) and medium (279,858 +/- 1,610), respectively. Similar to the jejunum, the colon was able to elaborate all the phospholipid classes, with phosphatidylcholine accounting for > 70% of tissue phospholipids. However, their individual levels were present in lesser amounts in the colon (P < 0.001). Colonic explants elaborated most of the major lipoprotein classes but were less efficient than jejunal explants in exporting chylomicrons (33-fold), very low density lipoprotein (1.5-fold), and high-density lipoprotein (9-fold) into the medium. Apolipoprotein (apo) B synthesis and apo B mRNA editing were comparable in colonic and jejunal explants; thus they are not responsible for the defective lipoprotein secretion in the fetal large bowel. These results establish for the first time te capability of the human fetal colon to form, but not to efficiently transport, lipids, lipoproteins, and apoproteins.

Impact of essential fatty acid deficiency on hepatic sterol metabolism in rats

The major aim of the current investigation was to define whether essential fatty acid (EFA) deficiency modifies the intrahepatic metabolism and biliary output of sterols in rats. EFA-deficient diet caused an impoverishment in linoleic, arachidonic, and docosahexaenoic acids, and a marked enrichment in the eicosatrienoic acid of the plasma, liver, and hepatic microsomes. During a short term of biliary drainage, a significant decline of the pool size of biliary sterols was noted in EFA-deficient rats compared with control rats. To assess the biosynthesis of biliary components, the common bile duct was cannulated and the pool size depleted (24 hours). Subsequently, a 6-hour bile collection disclosed a significant decrease (nmoles/min/g liver) in bile acids (4.8 +/- 0.3 vs. 8.4 +/- 0.7, P < .005), cholesterol (0.26 +/- 0.01 vs. 0.34 +/- 0.02, P < .05), and phospholipids (1.49 +/- 0.11 vs. 2.82 +/- 0.32, P < .005) in EFA-deficient rats compared with controls (n = 6/group). When cholesterogenesis was measured by the incorporation of [14C]acetate and 3H20 into cholesterol, using liver slices, it was also found to be significantly (P < .001) reduced in EFA-deficient rats. The activity of hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase, the rate-limiting enzyme in cholesterol biosynthesis, was consistently lower (80 percent, P < .001) in EFA-deficient rats. In parallel experiments, the direct measurement of microsomal acyl-CoA:cholesterol acyl-transferase (ACAT) showed a decrease averaging 52 percent (P < .001). This is in striking contrast to the elevated activity (157 percent, P < .005) of cholesterol 7 alpha-hydroxylase, the rate-limiting enzyme in bile acid biosynthesis. Current experiments also suggest that the enzyme regulation involving phosphorylation and dephosphorylation is modified by EFA deficiency. Among the structural alterations observed in the morphology of hepatocytes in EFA-deficient rats, the lumen of bile canaliculi was reduced in size. These results underline the importance of EFA in the major mechanisms involved in the maintenance of hepatocyte sterol balance.

Human lipoprotein lipase deficiency: does chronic dyslipidemia lead to increased oxidative stress and mitochondrial DNA damage in blood cells?

Lipoprotein lipase (LPL) is a key enzyme in the metabolism of lipoproteins and their balanced distribution in the plasma. A deficiency of this enzyme due to gene mutations leads to severe dyslipidemia. In this report, we describe the major LPL gene mutations that are prevalent in the French-Canadian population of Québec and the nature of dyslipidemia caused by the resulting enzyme deficiency. We discuss the possibility that dyslipidemia caused by LPL deficiency may enhance oxidative stress in the blood cells, bring about increased fluidity of the membrane components of these cells and increase the susceptibility of their mitochondrial DNA to structural alterations. Some preliminary experimental results in verification of this hypothesis are presented.

Reappraisal of hepatic arterial infusion in the treatment of nonresectable liver metastases from colorectal cancer

BACKGROUND

Metastases confined to the liver cause substantial morbidity and mortality for patients with colorectal cancer. The results of several randomized clinical trials conducted to study the effectiveness of hepatic arterial infusion (HAI) of fluoropyrimidines for the treatment of such patients have suggested that this treatment, as compared with systemic administration of fluoropyrimidines, increases the likelihood of tumor response. However, the impact of HAI on survival is unclear.

PURPOSE

A meta-analysis was carried out to provide an objective and quantitative appraisal of the benefits of HAI in terms of tumor response rate and overall patient survival.

METHODS

The meta-analysis was based on individual data provided by the principal investigators of six individual trials and on summary data for one trial. Of the seven trials, five compared HAI with floxuridine (5-fluoro-2'-deoxyuridine; FUDR) and intravenous chemotherapy (IVC) with FUDR (three trials) or fluorouracil (5-FU) (two-trials), and two compared HAI with FUDR and an ad libitum control group in which some patients could be left untreated. Response data were analyzed by use of a Mantel-Haenszel test on all randomized patients. Survival data were analyzed by the use of stratified logrank test. Multivariate analyses were performed with use of the logistic regression model for tumor response and the Cox regression model for survival. All P values resulted from two-sided statistical tests. The analyses were performed by an independent secretariat and were reviewed by the collaborators.

RESULTS

The tumor response rate was 41% for patients allocated to HAI with FUDR or 5-FU (CR, 2%; PR, 12%). This difference was highly significant, with a response odds ratio of 0.25 (95% confidence interval = 0.16-0.40; P < 10 (-10)). Survival analyses showed a statistically significant advantage for HAI with FUDR compared with control when trials were taken into account (P = .0009) but not when the survival analysis was restricted to trials comparing HAI with FUDR and IVC with FUDR or 5-FU (P = .14).

CONCLUSION

These results confirm that HAI can achieve much higher tumor response rates than systemic chemotherapy in patients with liver metastases from colorectal cancer.

IMPLICATIONS

The therapeutic benefit of use of HAI with FUDR in these patients should be judged together, with an overall evaluation of this therapy in terms of convenience, toxicity, and costs. These end points should be considered in addition to tumor response and survival in further trials involving HAI.

C-terminal fragments of alpha- and beta-tubulin form amyloid fibrils in vitro and associate with amyloid deposits of familial cerebral amyloid angiopathy, British type

Familial amyloidosis, British type, is an autosomal dominant disease characterized by progressive dementia, spastic paralysis and ataxia. The identity of the accumulating amyloid is not known, thus preventing the definitive classification of the disease. Biochemical methods were used to characterize the nature of the amyloid deposits from the brain tissue of one individual who died with this disease. The purified tissue material was subjected to trypsin digestion and subsequent N-terminal sequence analysis. Major tryptic fragments yielded the sequences VGINYQPPTVVPGGDLAK, FDLMYAK, GLTVPEL and GYLTVAAVFR, which are all tryptic fragments of the C-termini of human tubulin subunits alpha and beta. Synthetic peptides based on the sequences of these fragments formed amyloid fibrils in vitro fitting the characteristic definition of amyloid. These findings suggest that the C-terminal fragments of both alpha- and beta-tubulin are closely associated to the amyloid deposits of familial amyloidosis, British type.

Formularies in integrated health systems: Sharp HealthCare

Formulary management implications are described for a California health system consisting of 7 hospitals, 4 skilled-nursing centers, 22 medical clinics, 8 urgent care facilities, and a health maintenance organization. Sharp HealthCare serves nearly 1 million people in the San Diego area. A single institutional care division (ICD) pharmacy service has been created under the guidance of a steering committee consisting of a pharmacy operations coordinator and a staff pharmacist from each site, the system pharmacy director, the system senior pharmacy information systems specialists, and the system senior clinical pharmacy specialist. Operations at each site are overseen by an operations coordinator instead of a pharmacy director. Functional teams reporting to the steering committee are standardizing pharmacy processes, including formulary management; this is particularly important because the ICD has pharmacist and nurse per diem pools. Until 1995, formularies were independently managed at each site. Now, one system formulary is being developed. Standard policies and procedures, a nonformulary drug request form, and a monograph format have been completed. The hospitals' autonomous medical staffs have thus far elected to retain individual pharmacy and therapeutics (P&T) committees but approved a revamped formulary review process and systemwide P&T subcommittees. The computer system is being enhanced so that pharmacists anywhere in one of the hospitals will have access to applicable P&T committee-approved guidelines for drug use. Since vendors were advised that the system is establishing one formulary, Sharp has been able in some cases to achieve better pricing than it previously could through its purchasing group. Drug use is influenced by each site's pharmacy and therapeutics committee. The ideal, however, is to have this responsibility consolidated in a single systemwide committee.

Cerebrovascular amyloidosis in squirrel monkeys and rhesus monkeys: apolipoprotein E genotype

Some neuropathological changes characteristic of aging and Alzheimer's disease (AD) in humans are present also in senescent non-human primates. The human apoE4 allele is associated with an increased risk of developing late-onset familial and sporadic AD. We found that rhesus monkeys and three subspecies of squirrel monkeys are homozygous for apoE phenotype with arginine at positions 112 and 158 as in human apoE4. However, in both species threonine replaces arginine at position 61 of human apoE. It was previously shown that arginine 61 was critical in determining apoE4 lipoprotein distribution in humans.

French economic evaluations of influenza and influenza vaccination

The cost-of-illness studies of influenza performed in France or the years 1985 and 1989 have shown that the major economic consideration in the respective sizes of indirect and direct costs. Depending on the point of view (from the perspective of National Health Insurance or the societal perspective) and the method used for measuring indirect costs, it was estimated that they could be between 1.5 and 9 times higher than direct costs. A cost-benefit study of influenza vaccination for the employed adult population showed that vaccination is a cost-saving strategy, although this was also contingent upon the problems associated with measuring indirect benefits as well as the effectiveness rate of vaccination in real conditions.

Tumor necrosis factor-alpha inhibits lipid and lipoprotein transport by Caco-2 cells

Cytokines, important mediators of inflammation, have been shown to cause disturbances in circulating and hepatic lipid metabolism. Although the intestine plays a major role in dietary fat transport and largely contributes to plasma lipoproteins, the effects of cytokines on intestinal lipid handling remain unknown. In the present study, the modulation of lipid, apoprotein, and lipoprotein synthesis and secretion by tumor necrosis factor-alpha (TNF-alpha) was investigated in Caco-2 cells. Highly differentiated and polarized cells (20 days in culture) were incubated for 20 h with recombinant human TNF-alpha (100-500 ng/ml). No cytotoxic effect of TNF-alpha cells was observed, as indicated by the determinations of Caco-2 cell viability and monolayer transepithelial resistance. Moreover, no differences in cell maturation (sucrase activity) or cell proliferation ([3H]thymidine incorporation and cell cycle analysis) were detected between treated and control cultures. Significant inhibition of lipid secretion by TNF-alpha was observed, with the greatest reduction at 500 ng/ml. TNF-alpha significantly decreased Caco-2 cell secretion of phospholipids (22%), triglycerides (30%), and cholesteryl ester (37%). It also significantly diminished the export of newly synthesized low-density lipoproteins (LDL; 20%) and high-density lipoproteins (HDL; 13%), with a lesser effect on very low-density lipoproteins (VLDL; 3%). The lipid composition of these lipoproteins was minimally affected. De novo synthesis of apo A-I, apo B-100, and apo B-48 was also markedly reduced by TNF-alpha. Sphingomyelinase activity was not increased and cell content of sphingomyelin was not altered, suggesting that inhibitory effects on lipid and apoprotein of TNF-alpha were not mediated by the ceramide pathway. Our results indicate that TNF-alpha may play a role in modulating intestinal lipid metabolism, thus affecting circulating lipoproteins.

Cystatin C mutation in an elderly man with sporadic amyloid angiopathy and intracerebral hemorrhage

BACKGROUND

Cerebral amyloid angiopathy (CAA) with intracerebral hemorrhage (ICH) occurs both sporadically and as a result of mutations in either cystatin C or the amyloid precursor protein. ICH due to cystatin C mutations typically occurs in young people of Icelandic origin.

CASE DESCRIPTION

We report a case of sporadic CAA with ICH in an elderly Croatian man with a mutation in cystatin C identical to that found in Icelandic hereditary cerebral hemorrhage with amyloidosis.

CONCLUSIONS

This is the first case report of sporadic CAA associated with the same mutation causing hereditary cerebral hemorrhage with amyloidosis of the Icelandic type. Sporadic CAA may thus be associated with genetic mutations in some patients. The frequency of these mutations is yet to be determined.

Essentiality of omega-3 and omega-6 fatty acids for efficient liver sterol metabolism

Abundant data from both experimental animals and humans now support the conclusion that the incidence of atherosclerosis is related to the concentration of plasma cholesterol. Cholesterol homeostasis in the body is maintained by regulatory mechanisms, which control the input and output processes. The liver plays a key role in cholesterol balance. In this organ, the major part of the cholesterol synthesis, cholesterol conversion to bile acids and the delivery of cholesterol to the plasma in the form of lipoprotein remnants, low and high density lipoproteins. While many studies have related dietary intake of fatty acids to concentrations of cholesterol in the circulation, their potential effects on liver sterol metabolism have received relatively less attention. However, the liver represents the target of many stimuli capable of affecting cholesterol homeostasis. This review will focus on the regulation of liver sterol metabolism by omega-3 versus omega-6 fatty acids.

beta-Amyloid precursor protein gene in squirrel monkeys with cerebral amyloid angiopathy

Senescent nonhuman primates frequently develop cerebral beta-amyloidosis; for reasons that are not yet understood, the primary histological locus of beta-amyloid deposition varies in different species. In aged rhesus monkeys (Macaca mulatta), fibrillar (congophilic) beta-amyloid (A beta) occurs most frequently in senile plaques, whereas in aged squirrel monkeys (Saimiri sciureus) the cerebral blood vessels are most affected. To determine if cerebral beta-amyloid angiopathy (CAA) in squirrel monkeys is related to a species-specific amino acid change in A beta, as was shown in two hereditary human forms of CAA, the beta-amyloid precursor protein (beta PP) cDNA was sequenced. The predicted amino acid sequence of A beta in squirrel monkeys is identical to that in normal humans. Overall, beta PP751 in the squirrel monkey differs from the human sequence only by four amino acids near the N-terminus and in the KPI domain. These findings suggest that other factors most likely predispose aged squirrel monkeys to cerebral amyloid angiopathy. We propose the squirrel monkey as a useful model for studying the factors contributing to human CAA, and for testing diagnostic and therapeutic approaches to this disorder.

Atypical MR appearance of Lhermitte-Duclos disease with contrast enhancement

A case of surgically confirmed Lhermitte-Duclos disease demonstrated contrast enhancement on MR. Histologic examination verified corresponding increased vascularity in the molecular layer and adjacent leptomeninges.

Enalapril treatment of posttransplant erythrocytosis: efficacy independent of circulating erythropoietin levels

To determine the mechanism of action by which angiotensin-converting enzyme (ACE) inhibitors lower hematocrit in patients with posttransplant erythrocytosis, indices of red blood cell production and red blood cell destruction were obtained serially for 6 months from 10 renal transplant patients receiving treatment with enalapril for this problem. Before treatment, five patients had an elevated red blood cell mass, four had plasma volume contraction, and one had both. The mean hemoglobin concentration decreased by 2 g/dL (range, 0.5 to 3.3 g/dL), from 17 +/- 1 g/dL to 15 +/- 1 g/dL (P = 0.001) following 6 months of enalapril therapy. Similarly, the mean hematocrit decreased by 8% (range, 3% to 12%), from 52% +/- 2% to 44% +/- 3% (P = 0.001) during the same period. The mean reticulocyte count tended to decrease, although the change was not significant. The red blood cell mass decreased dramatically by 15% to 50%, from 32 +/- 9 mL/kl to 23 +/- 4 mL/kg (P = 0.008). Although serial erythropoietin levels declined steadily in two patients, there was no consistent change in the other patients. Mean levels decreased modestly, from 20 +/- 11 mU/mL at baseline to 12 +/- 5 mU/mL at 6 months, a change that was not statistically significant. Mean levels at each time point were not statistically different from the mean pretreatment value. Furthermore, during enalapril therapy, there was no correlation between mean circulating erythropoietin level and mean hematocrit (r = 0.43, P = 0.20) or hemoglobin concentration (r = 0.36, P = 0.30) or between changes in these parameters.(ABSTRACT TRUNCATED AT 250 WORDS)

Familial hypercholesterolemia: molecular, biochemical, and clinical characterization of a French-Canadian pediatric population

BACKGROUND

Familial hypercholesterolemia (FH) is a dominantly-inherited disorder attributable to a defect in the low-density lipoprotein (LDL) receptor gene. Five mutations at this locus have been identified in French-Canadians. In children, it may be difficult to clinically distinguish FH from other forms of polygenic or monogenic hyperlipidemia. Therefore, our objectives were to define the molecular basis of our subjects' hypercholesterolemia, to characterize their biochemical phenotype in relation to the underlying molecular defect, and to assess their response to chronic dietary therapy.

METHODS

We studied 88 unrelated French-Canadian children with a persistent increase in LDL cholesterol and a parental history of hyperlipidemia. Baseline and end-of-diet lipid and apolipoprotein levels were measured. Mutational analysis at the LDL receptor gene locus was performed.

RESULTS

Heterozygosity for the common French-Canadian LDL receptor gene > 10-kb deletion was found in 57% of subjects (group 1), 14% carried one of the other four previously characterized LDL receptor gene mutations (group 2), and none of the five molecular defects tested was detected in 29% (group 3). Total cholesterol, LDL cholesterol, and apolipoprotein B baseline levels were similar among these three groups but significantly higher than in control subjects. However, there was wide interindividual variability even among those carrying the same mutation. Significantly lower baseline levels of high-density lipoprotein cholesterol and apolipoprotein A1 were found in group 1 compared with group 3 and the controls. The response to diet was similar among the three groups with an average reduction in the mean level of total cholesterol of 4.4%.

CONCLUSIONS

The frequency of proven FH heterozygotes (71%) was remarkable in the pediatric population studied. Our data suggest that, in children, a persistent primary increase in LDL cholesterol associated with a parental history of hyperlipidemia is a good predictor of an underlying monogenic disorder as opposed to a polygenic disorder, at least in French-Canadians. Only molecular analysis allowed us to unequivocally define the cause of our patients' hypercholesterolemia. Most children with familial hyperlipidemia did not reach desirable plasma lipid levels solely under diet therapy.

Immunocytochemical investigation of insulin secretion by pancreatic beta-cells in control and diabetic Psammomys obesus

Hyperproinsulinemia is a characteristic feature of non-insulin-dependent diabetes mellitus (NIDDM) caused by pancreatic beta-cell dysfunction through a secretion-related alteration or impaired proinsulin processing. We have investigated the insulin processing and secretion in Psammomys obesus fed with low- and high-energy diets, which represent a model for diet-induced NIDDM. With a high-energy diet the animals develop hyperglycemia and hyperinsulinemia, whereas those maintained on a low-energy diet remain normoglycemic. Although a large amount of insulin immunoreactivity was detected in beta-cells of the normoglycemic compared to hyperglycemic animals, in situ hybridization for insulin mRNA demonstrated a particularly high signal in the beta-cells of the hyperglycemic animals. By electron microscopy, the beta-cells of normoglycemic animals displayed large accumulations of secretory granules, whereas those of the hyperglycemic animals contained very few granules and large deposits of glycogen. These results reflect a secretory resting condition for the cells of the normoglycemic animals in contrast to stimulated synthetic and secretory activities in the cells of the hyperglycemic ones. Using colloidal gold immunocytochemistry at the electron microscopic level, we have examined subcellular proinsulin processing in relation to the convertases PC1 and PC2. Immunolabeling of proinsulin, insulin, C-peptide, PC1, and PC2 in different cell compartments involved in beta-cell secretion were evaluated. Both PC1 and PC2 antigenic sites were detected in beta-cells of hyperglycemic Psammomys, but their labeling intensity was weak compared to the cells of normoglycemic animals. In both groups of animals, higher levels of PC2 were found in the Golgi apparatus than in the immature granules. Major decreases in proinsulin, insulin, PC1, and PC2 immunoreactivity were recorded in beta-cells of the hyperglycemic Psammomys. In addition, all these antigenic sites were detected in lysosome-like structures, revealing a major degradation process. These results suggest that the insulin-secreting cells in hyperglycemic Psammomys obesus are in a chronic secretory state during which impaired processing of proinsulin appears to take place.

Malondialdehyde-modified HDL leads to accumulation of cholesterol in rat liver endothelial cells

In order to study in vivo the effect of modified high density lipoprotein (HDL) on the movement of free cholesterol to liver cells and bile, we injected i.v. into rats, native or malondialdehyde modified HDL labelled with [14C]cholesterol. Bile analysis indicated that the contribution of labelled cholesterol to bile acid secretion was diminished in the group receiving MDA-modified HDL when compared to control group. On the other hand, the liver analysis revealed higher radioactivity in the treated group. A separation of liver cells into parenchymal, endothelial, and kupffer at 90 min after the injection of MDA-modified HDL or native HDL indicated that the endothelial cell uptake of labelled free cholesterol from MDA-modified HDL was 2.6-fold higher than for native HDL. It is suggested that liver endothelial cells may be involved in the protection against atherogenoic oxidized lipoprotein. However, with regard to our finding, the uptake of cholesterol from modified HDL was detrimental to bile acid secretion.

Isolated renal mucormycosis: case report and review

The 15th reported case of isolated renal mucormycosis (infection of the kidney with fungus of the order Mucorales, in the absence of infection elsewhere in the body) is presented. The patient was a 36-year-old human immunodeficiency virus-infected man, actively using iv drugs, who suffered 6 wk of flank pain and fever before diagnosis was made by percutaneous renal biopsy. He received 4 months of amphotericin B treatment, then no therapy for 6 months before dying with no evidence of mucormycosis. Isolated renal mucormycosis should be suspected in those with an underlying immunocompromising illness or history of iv drug use who have persistent flank pain and fever, but sterile urine cultures. Computed tomographic scanning with contrast should then be performed; findings of severe inflammation or bacterial infection, despite an indolent clinical course with sterile or nondiagnostic urine and blood cultures, are suggestive of isolated renal mucormycosis, and renal biopsy under computed tomographic guidance should be performed, despite the potential risk of disseminated infection. Although our patient was treated with amphotericin B alone, nephrectomy with or without amphotericin B therapy appears to be more likely to cure infection and relieve pain and constitutional symptoms.

The relationships among serum uric acid, plasma insulin, and serum lipoprotein levels in subjects with spinal cord injury

Relationships were investigated among serum uric acid (UA), the insulin response to a standard oral glucose load (75 g), and serum lipoprotein levels in 197 individuals with chronic spinal cord injury (SCI). All subjects had normal liver and renal function. None had a prior history of diabetes mellitus or gout. The mean age of subjects was 50 +/- 1 years, duration of injury (DOI), 18 +/- 1 years, and body mass index (BMI), 25 +/- 0.4 kg/m2. No significant differences were found between those with paraplegia or quadriplegia for any of the parameters measured. The mean serum UA values were not significantly different among the subgroups of subjects with normal glucose tolerance, impaired glucose tolerance, or diabetes mellitus (5.6 +/- 0.2 mg/dl, 5.6 +/- 0.2 and 5.7 +/- 0.3, respectively). Approximately one-half of the subjects had an abnormality in oral glucose tolerance. The levels of serum UA (p < 0.001) and serum triglycerides (TG) (p < 0.01) in the subgroup with hyperinsulinemia were significantly higher than in the subgroup with normal insulin levels. By linear regression analyses, the serum UA concentration was positively correlated with peak plasma insulin level (r = 0.31, p < 0.001), and BMI (r = 0.20, p < 0.01), but not with age, DOI, or peak glucose. The data suggest that in subjects with chronic SCI, as in the healthy able-bodied population, hyperuricemia is associated with hyperinsulinemia, obesity and abnormal lipoprotein metabolism.