Renin-producing adrenal tumor: report of a case

A 19-year-old man with an adrenal tumor associated with hypertension is herein described. The plasma renin activity (PRA) was markedly elevated and the plasma aldosterone level was also increased. The catecholamine level was within the normal range and the glucagone-regitine test was negative. An angiogram revealed the left renal artery to have no stenotic segments, but instead was curved caudally. Magnetic resonance imaging showed a tumor measuring about 8 cm in diameter to be clearly recognized from the left kidney. The blood pressure did not drop when a calcium-channel blocker was used, but was gradually stabilized with the angiotensin converting enzyme (ACE) antagonist. The adrenal tumor was then removed surgically. Normal adrenal tissue was scarcely recognized to the left of the tumor. After surgery, the PRA decreased and blood pressure stabilized rapidly without the ACE antagonist. The possibility of massive renal renin secretion due to suppression by the adrenal tumor was excluded by a method using an antibody to purified human renin.

Involvement of calcineurin in Ca2+ paradox-like injury of cultured rat astrocytes

The Ca2+/calmodulin-dependent phosphatase calcineurin may have physiological and pathological roles in neurons, but little is known about the roles of the enzyme in glial cells. We have previously reported that reperfusion of cultured astrocytes in Ca2+-containing medium after exposure to Ca2+-free medium caused Ca2+ influx followed by delayed cell death. In this study, we examined if calcineurin is involved in this Ca2+-mediated astrocytic injury. FK506, an inhibitor of calcineurin, protected cultured rat astrocytes against paradoxical Ca2+ challenge-induced injury in a dose-dependent manner (10(-10)-10(-8) M). Cyclosporin A at 1 microM mimicked the effect of FK506. Rapamycin (1 microM) did not affect astrocyte injury, but it blocked the protective effect of FK506. Deltamethrin (20 nM), another calcineurin inhibitor, had a similar protective effect, whereas okadaic acid did not. FK506 affected neither paradoxical Ca2+ challenge-induced increase in cytosolic Ca2+ level nor Na+-Ca2+ exchange activity in the cells, suggesting that the calcineurin is involved in processes downstream of increased cytosolic Ca2+ level. Immunochemical studies showed that both calcineurin A (probably the A beta2 isoform) and B subunits were expressed in the cells. It is concluded that calcineurin is present in cultured astrocytes and it has a pathological role in the cells.

Role of Na(+)-Ca2+ exchanger in agonist-induced Ca2+ signaling in cultured rat astrocytes

We have previously demonstrated that activation of the Na(+)-Ca2+ exchanger in the reverse mode causes Ca2+ influx in astrocytes. In addition, we showed that the exchange activity was stimulated by nitric oxide (NO)/cyclic GMP and inhibited by ascorbic acid. The present study demonstrates that the Na(+)-Ca2+ exchanger is involved in agonist-induced Ca2+ signaling in cultured rat astrocytes. The astrocytic intracellular Ca2+ concentration ([Ca2+]i) was increased by L-glutamate, noradrenaline (NA), and ATP, and the increases were all attenuated by the NO generator sodium nitroprusside (SNP). SNP also reduced the ionomycin-induced increase in [Ca2+]i. The NA-induced Ca2+ signal was also attenuated by S-nitroso-L-cysteine and 8-bromo cyclic GMP, whereas it was enhanced by 3,4-dichlorobenzamil, an inhibitor of the Na(+)-Ca2+ exchanger. Treatment of astrocytes with antisense, but not sense, deoxynucleotides to the sequence encoding the Na(+)-Ca2+ exchanger enhanced the ionomycin-induced increase in [Ca2+]i and blocked the effects of SNP and 8-bromo cyclic GMP in reducing the NA-induced Ca2+ signal. Furthermore, the ionomycin-induced Ca2+ signal was enhanced by removal of extracellular Na+ and pretreatment with ascorbic acid. These findings indicate that the Na(+)-Ca2+ exchanger is a target for NO modulation of elevated [Ca2+]i and that the exchanger plays a role in Ca2+ efflux when [Ca2+]i is raised above basal levels in astrocytes.

Heat shock protects cultured rat astrocytes in a model of reperfusion injury

We have previously found that incubation of cultured rat astrocytes in Ca(2+)-free medium caused an increase in intracellular Ca2+ ([Ca2+]i) followed by delayed cell death. Here, we examined whether thermal stress protects astrocytes from cell death in this model system of reperfusion injury. Cultured astrocytes were preincubated at 40-44 degrees C for 10-20 min in fetal calf serum-free medium, incubated at 37 degrees C for 24 h in serum-containing medium, and subjected to the in vitro reperfusion experiment. Thermal stress attenuated reperfusion-induced cell toxicity. Furthermore, the stress increased cell viability after incubation with serum-free medium containing Ca2+. These effects of heat shock required incubation in serum-containing medium for at least 12 h after heat shock, and it was blocked by the protein synthesis inhibitor cycloheximide. Thermal stress increased synthesis of several proteins, and one of the inducible proteins was identified as the 72-kDa heat shock protein by an immunoblot analysis. Neither the increase in [Ca2+]i nor the Na(+)-Ca2+ exchange activity in astrocytes induced in this model were affected by thermal stress. These findings suggest that heat shock proteins protect astrocytes from cell death in a model of reperfusion injury and they may affect processes down stream of the increase in [Ca2+]i.

Ca2+ depletion facilitates taurine release in cultured rat astrocytes

Removal of external Ca2+ facilitated endogenous taurine release in cultured rat astrocytes. The stimulated release was not affected by furosemide, sucrose, tetrodotoxin and 3,4-dichlorobenzamil, but partially inhibited by nifedipine. Omission of external Na+ increased basal taurine release, and the effects of Na+ removal and Ca2+ depletion on the release were additive. The Na(+)-free condition did not affect Ca2+ paradox-induced cell death in astrocytes. These findings suggest that Ca2+ depletion facilitates taurine release in a mechanism independent of volume and the Na+ gradient and that the release is not involved in Ca2+ paradox-induced delayed cell toxicity in astrocytes.

Protective effect of taurine against reperfusion injury in cultured rat astrocytes

Reperfusion of cultured rat astrocytes with Ca(2+)-containing medium after exposure to Ca(2+)-free medium for a short time caused an increase in intracellular Ca2+ ([Ca2+]i), and delayed cell death (Ca2+ paradox-like injury). Exposure of astrocytes to Ca(2+)-free medium caused a marked release of taurine. Taurine (3-30 mM) reduced the reperfusion-induced increase in [Ca2+]i and attenuated the delayed glial cell death. Glycine, GABA and beta-alanine did not affect reperfusion-induced cell toxicity. The protective effect of taurine required addition at an early time during reperfusion. Ouabain and monensin mimicked reperfusion injury and their toxicity was also reduced by taurine. Taurine (3-30 mM) inhibited dose-dependently 45Ca2+ uptake stimulated by ouabain and monensin in astrocytes. These findings suggest that taurine has a protective effect against reperfusion injury via an inhibition of Na+/Ca2+ exchange activity in the reverse mode.

Predictive factors for efficacy of interferon therapy in chronic hepatitis type C

BACKGROUND/AIMS

It has recently become possible to quantify HCV-RNA in serum and to analyze the HCV-RNA genotype. In this study, we investigated the relationship among the response to interferon therapy, the HCV-RNA concentration, genotype and histological findings of the liver.

PATIENTS AND METHODS

Sixty-three patients with chronic hepatitis type C received interferon alfa therapy for 24 weeks. The HCV-RNA concentration in serum was measured semiquantitatively with reverse transcript semi-nested polymerase chain reaction and classified as negative to +3. HCV-RNA genotype was analyzed using a mixture of four type specific primers.

RESULTS

HCV-RNA concentration was significantly higher in patients with genotype II and CAH2B than genotype III, CPH and CAH2A (p < 0.05). At 24 weeks after the end of interferon therapy, HCV-RNA in serum disappeared in 24 of 63 patients (38%). Strong resistance to the therapy was noted in patients with both genotype II and a high concentration of HCV-RNA in serum (the efficacy was only 7%). Therapy efficacy decreased with the severity of liver histological findings, reaching only 20% in those with CAH2B.

CONCLUSION

Both the concentration and genotype of HCV-RNA seem to be important factors in determining the efficacy of interferon therapy.

Ability of prolonged interferon treatment to suppress relapse after cessation of therapy in patients with chronic hepatitis C: a multicenter randomized controlled trial

The aim of this study was to determine whether 12 months course of interferon alfa (IFN-alpha) therapy could improve the beneficial effect of IFN in chronic hepatitis C. Eighty-eight patients were treated with natural IFN-alpha for either 28 weeks (45 cases) or 52 weeks (43 cases). Sustained response was achieved in 15 (33.3%) of 45 cases treated for 28 weeks and in 23 (53.5%) of 43 cases treated for 52 weeks. Transient response with relapse of alanine transaminase (ALT) after completion of therapy was observed in 13 cases (28.9%) treated for 28 weeks and in 4 cases (9.3%) treated for 52 weeks. Thus, ALT relapse was suppressed by prolonged IFN treatment. No response was found in 17 cases (37.8%) treated for 28 weeks and in 16 cases (37.2%) treated for 52 weeks, indicating that approximately 38% of the patients with chronic hepatitis C were resistant to IFN therapy even with prolonged treatment. The rate of sustained response was significantly higher in patients with type 2a or 2b than in those with type 1b. Even in type 1b cases, it was higher in the 52-week treatment group than in the 28-week treatment group, and the rate of transient response was lower in the 52-week treatment group, indicating that relapse in type 1b cases was suppressed by prolonged IFN therapy. IFN therapy was not effective for patients with advanced liver fibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Three-dimensional display of liver, spleen, hepatoma, and blood vessels by MR imaging and computer graphics

The technique of generating 3-D images from CT and MR data has made progress. Manipulation of the images has become simpler, the processing time shorter, and the quality better. Clinical application of this technique has been performed for images of brain (5, 7, 8) and bone (1, 2, 6), but only a few studies have been done of abdominal organs (3, 4).

Pulmonary venoocclusive disease in a patient with systemic lupus erythematosus

A 26-year-old woman with systemic lupus erythematosus (SLE) developed dyspnea and hypoxemia on exertion. She died from rapidly progressive respiratory failure. Autopsy revealed right ventricular hypertrophy and occlusion of the pulmonary veins compatible with pulmonary venoocclusive disease (PVOD). Although PVOD has been reported in patients with suspected collagen vascular disease, this appears to be the first reported case of PVOD occurring in a patient with SLE.

Prevalence of hepatitis C virus in family members of patients with hepatitis C

To investigate the prevalence of hepatitis C virus in the family members of patients with hepatitis C, we examined antibody to hepatitis C virus with a second-generation enzyme-linked immunosorbent assay and viral RNA with a combined assay of reverse transcription and polymerase chain reaction in sera. Among 219 (75 spouses, 110 children, and 34 others), 26 (12%) were antibody positive. The positive rate of antibody to hepatitis C virus was significantly higher than that of the control group (2.0%) and of volunteer blood donors in our district (1.5%), and it increased with age. In particular, the positive rate of antibody to hepatitis C virus among spouses was high (24%). Among family members with elevated ALT, 59% were antibody positive, which was significantly higher than that of the control group (11%). Of the 26 who were antibody positive, 21 (81%) had viral RNA, whereas of the 70 who were antibody negative, only one (1.4%) had viral RNA. These data suggest that hepatitis C virus was transmitted by the infrafamilial route during long duration of contact with patients or sexual transmission. In family members, hepatitis C viral infection is the main cause of liver disorder, and many who were antibody-positive with a second-generation enzyme-linked immunosorbent assay had viremia in the sera.

[Research and development of pravastatin]

The attempts to find a potent inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase which catalyzes the rate limiting step of cholesterol biosynthesis were started from 1971. The first potent inhibitor, ML-236B (compactin), was found from the culture broth of Penicillium citrinum. Among many derivatives of ML-236B, pravastatin sodium (hereafter refer to pravastatin) was finally selected because of its potency and tissue selectivity. Since pravastatin has a hydroxyl group at 6 beta position in the skeleton of decaline of ML-236B, the microbial hydroxylation was adopted for the production of pravastatin. Streptomyces carbophilus was finally chosen as a potent converter with the formation of a lesser amount of by-products. For the sake of industrial production of pravastatin, many devices and improvements were performed for selecting high potent strains and for culturing conditions both with ML-236B and pravastatin. Pravastatin strongly inhibited the sterol synthesis in freshly isolated rat hepatocytes, but only weakly inhibited in the cells from nonhepatic tissues. This selective inhibition of pravastatin in sterol synthesis was further confirmed by ex vivo and in vivo experiments by using rats and mice. Pravastatin markedly reduced serum cholesterol levels in dogs, monkeys and rabbits, including Watanabe heritable hyperlipidemic (WHHL) rabbits, an animal model for familial hypercholesterolemia. Pravastatin showed the preventive effect on the development of coronary atherosclerosis and xanthoma in young WHHL rabbits in consequence of maintaining the serum cholesterol levels low. In the clinical trials, pravastatin significantly reduced serum cholesterol and low density lipoprotein cholesterol levels, whereas inversely increased high density lipoprotein cholesterol levels.

Management of congenital diaphragmatic hernia by extracorporeal membrane oxygenation (ECMO)

The purpose of this study was to evaluate the efficacy of extracorporeal membrane oxygenation (ECMO) for patients with congenital diaphragmatic hernia (CDH). Ten patients whose mortality was predicted to be more than 80% with previous therapeutics, were selected to use ECMO over the past five years. Patients were placed on ECMO by cannulating the right jugular vein and the right carotid artery. ECMO was started at 34.3 hours after birth on an average, and the average time on ECMO was 96.3 hours. Seven patients (70%) survived, and six out of them are in good health without any sequelae. In particular, all five patients whose pathological condition needing ECMO was persistent fetal circulation (PFC), survived. Therefore we believe ECMO is highly beneficial to overcome the condition of PFC. The survival rate of CDH patients under 24 hours of age in our hospital is 76.2% (16/21 cases) over the last 5 years, and it has improved compared with 57.1% (12/21 cases) before then. The fact that some of the critical patients who were lethal with conventional management, have been successfully treated by ECMO, played a great role in this improvement.

Fv-1 restriction of endogenous feline C-type RD114 virus genome phenotypically mixed with ecotropic murine leukemia viruses

Endogenous feline leukemia RD114 virus genome rendered capable of infecting mouse cells by phenotypic mixing with an ecotropic murine leukemia virus (MuLV) exhibited the Fv-1 restriction pattern of the ecotropic murine virus. However, RD114 genomes phenotypically mixed with ecotropic MuLV showed one-hit dose-response kinetics, even when titrated with murine cells with the restricted Fv-1 phenotype.

Mutational analysis of the human immunodeficiency virus vpr open reading frame

Mutations were introduced by recombinant DNA techniques into the vpr open reading frame of an infectious molecular clone of human immunodeficiency virus type 1. The effect of these changes on the replicative and cytopathologic properties of the virus recovered from transfected cells was studied in several human CD4+ lymphocyte cell lines. In all cases, mutant viruses were infectious and cytopathic. However, when a low-input dose was used, mutants grew significantly more slowly than the wild-type virus. The growth kinetics of vpr mutants were distinct from those of vif and vpu mutants.

Purification of phenylalanine hydroxylase from human adult and foetal livers with a monoclonal antibody

Phenylalanine hydroxylase from adult and foetal livers was purified by single step monoclonal antibody affinity chromatography. From adult and foetal livers, about 1280- and 1450-fold purified enzymes were obtained with 37% and 23% yield, respectively. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of the resultant adult enzyme showed an essentially single band with an apparent molecular weight of 49K. On the other hand, two subunits (molecular weights 52K and 49K) were observed from the foetal enzyme. Molecular weights of the native adult and foetal enzymes as determined on Sepharose CL-6B column chromatogram were 150K and 160K, respectively. It was clear that adult and foetal liver phenylalanine hydroxylases were different proteins having different subunit molecular weights.

Effect of acute and chronic ethanol consumption on hepatic tissue oxygen tension in rats

In vivo hepatic tissue oxygenation was investigated in chronically ethanol-treated rats using micro oxygen electrode and reflectance spectrophotometry. Effect of acute ethanol administration was also studied. Hepatic oxygen tension of rats treated with ethanol chronically (daily ethanol intake, 9-12 g/kg for 9 months) was very low as compared with that of normal rats, the decrease being comparable to that of rats treated with carbon tetrachloride. The hepatic oxygen tension in normal controls shortly after ethanol ingestion increased from basal level (median, 23 mmHg) to 40-70 mmHg, while in chronically ethanol-treated rats, the hepatic oxygen tension decreased transiently, followed by a gradual increase, but it still remained low. In CCl4-treated rats, the hepatic oxygen tension decreased further after the ethanol ingestion. It is concluded that chronic ethanol consumption in rats resulted in hepatic hypoxia with decreased liver blood flow and volume. Also acute ethanol administration does not induce hepatic hypoxia in normal rats, while in rats with injured liver it induces hypoxia.

Cadmium toxicity and liver mitochondria. I. Different effects of cadmium administered in vivo to adult, young, and ethionine-fed rats

The changes in liver mitochondrial respiratory activities and cytochrome concentrations were investigated when cadmium chloride was administered orally to adult, young, and ethionine-fed rats. Following a seven-day administration of 30 ppm cadmium in drinking water, adult rats showed no change, while young rats and ethionine-fed rats exhibited a marked increase in mitochondrial respiration with concomitant decrease of respiratory control index and P/O ratio. The concentrations of cytochromes aa3, b, and c + c1 in liver mitochondria were unchanged in adult rats, but increased significantly in ethionine-fed rats. In young rats receiving cadmium the liver mitochondrial protein increased with a slight change in the cytochrome concentration in mitochondria. It was further found that in adult rats a higher concentration (300 ppm) of cadmium in drinking water was toxic to the liver mitochondrial functions. Thus, the effect of oral administration of cadmium on the liver mitochondrial function depends on the condition of the animals.

Hydroxylation of (Pro-Pro-Gly)5 and (Pro-Pro-Gly)10 by prolyl hydroxylase. Evidence for an asymmetric active site in the enzyme

Previous studies with 14C-labeled synthetic peptides demonstrated that prolyl hydroxylase, which synthesizes the hydroxyproline in collagen, preferentially hydroxylates the fourth triplet from the NH-terminal end of the peptide (Pro-Pro-Gly)5. In the experiments reported here, the prolyl hydroxylase reaction was investigated further by preparing chemically modified derivatives of (Pro-Pro-Gly)5 and by synthesizing 14C-labeled preparations of (Pro-Pro-Gly)10. Essentially, the same kcat value was found for the hydroxylation of (Pro-Pro-Gly)5, N-acetyl-(Pro-Pro-Gly)5, (Pro-Pro-Gly)5 methyl ester, (Pro-Pro-Gly)10, and for larger polypeptide substrates of the enzyme. It appeared therefore that preferential hydroxylation of specific triplets in peptides of the structure (Pro-Pro-Gly)n cannot be explained by differences in the kinetic constants for individual triplets. Hydroxylation of 14C-labeled preparations of (Pro-Pro-Gly)10 demonstrated that the ninth triplet was preferentially hydroxylated over any other triplet. The results were best explained by the hypothesis that prolyl hydroxylase has an asymmetric active site in which binding subsites are located adjacent to but not symmetrical with the catalytic subsite.

Further characterization of embryonic tendon fibroblasts and the use of immunoferritin techniques to study collagen biosynthesis

Morphological studies were carried out on fibroblasts from chick embryo tendons, cells which have been used in a number of recent studies on collagen biosynthesis. The cells were relatively rich in endoplasmic reticulum and contained a well-developed Golgi complex comprised of small vesicles, stacked membranes, and large vacuoles. Techniques were then devised for preparing cell fragments which were penetrated by ferritin-antibody conjuates but which retained the essential morphological features of the cells. Finally, the new procedures were employed to develop further information as to how collagen is synthesized. As reported elsewhere, preliminary studies with ferritin-labeled antibodies showed that prolyl hydroxylase was found in the endoplasmic reticulum of freshly isolated fibroblasts and that procollagen is found in both the cisternae of the endoplasmic reticulum and the large Golgi vacuoles. In the experiments described here, the cells were manipulated so that amino acids continued to be incorporated into polypeptide chains but assembly of the molecule was not completed because hydroxylation of prolyl and lysyl residues was prevented. The results indicated that these manipulations produced no change in the distribution of prolyl hydroxylase. Examination of the cells with ferritin conjugated to antibodies which reacted with protocollagen, the unhydroxylated form of procollagen, demonstrated that protocollagen was retained in the cisternae of the endoplasmic reticulum during inhibition of the prolyl and lysyl hydroxylases. Assays for prolyl hydroxylase with an immunologic technique demonstrated that although the enzyme is found within the endoplasmic reticulum, it is not secreted along with procollagen. The observations provided further evidence for a special role for prolyl hydroxylase in the control of collagen biosynthesis.

Two improved methods for preparing ferritin-protein conjugates for electron microscopy

Two improved procedures were developed for activating ferritin so that the ferritin could be covalently linked to antibodies. One procedure involved use of a water-soluble carbodiimide and N-hydroxysuccinimide to prepare ferritin-containing activated esters. The other involved activation of the ferritin with excess glutaraldehyde. The ferritin-antibody conjugates prepared with the two procedures were shown to have a number of properties which made them suitable for locating antigenic components in cells.

Collagen synthesis: localization of prolyl hydroxylase in tendon cells detected with ferritin-labeled antibodies

An improved procedure was employed for linking ferritin to antibodies against prolyl hydroxylase, the enzyme that synthesizes the hydroxyproline in collagen. By electron microscopy, the enzyme was then found to be localized in cisternae of the rough endoplasmic reticulum of embryonic tendon cells; this indicates that hydroxylation of proline occurs while newly synthesized polypeptides are fed into the cisternae.