Adenine arabinoside is an antiviral agent which has been used in a number of clinical studies for the treatment of chronic infections with hepatitis B virus. In order to better understand its effects and mode of action, we treated ducks chronically infected with duck hepatitis B virus with a 2-week course and monitored the effects of the drug on viral replication by studying duck hepatitis B virus DNA in liver and serum using molecular biological techniques. We found the drug to be effective in ducks only at much higher doses than those used in humans. At high doses, adenine arabinoside had a dose-related inhibitory effect on viral replication during treatment, but there was a rapid return toward baseline values soon after the cessation of treatment. The supercoiled form of viral DNA was found to be most resistant to adenine arabinoside therapy, and the drug had a disproportionate inhibitory effect on viral plus (noncoding) strand synthesis. We conclude that adenine arabinoside likely exerts its effect in hepadna virus infections predominantly through inhibition of viral DNA polymerase. On the basis of our current study and previous trials in hepatitis B virus-infected patients, we predict that adenine arabinoside will not efficiently eliminate viral replication in chronic hepadna virus infection, when used as the sole therapeutic modality. Adenine arabinoside may have a role to play as an adjunct to immunomodulation or interferon therapy in chronic hepatitis B virus infection in man.

Animals↗

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Xenon inhalation increases norepinephrine release from the anterior and posterior hypothalamus in rats.

PURPOSE: To investigate the effect of xenon (Xe) and nitrous oxide (N(2)O) on norepinephrinergic neuronal activity in the rat medial preoptic area (mPOA) and posterior hypothalamus (PH) using microdialysis. METHODS: Sixty male Wistar rats were equally allocated to two groups: mPOA and PH. A microdialysis probe was implanted into the mPOA or the PH. In both groups, each animal was exposed to one of the following inhalations: 25% oxygen (control, n=6), 30% Xe (n=6), 60% Xe (n=6), 30% N(2)O (n=6) or 60% N(2)O (n=6). Norepinephrine concentration in the perfused artificial cerebrospinal fluid was measured by high pressure liquid chromatography at ten-minute intervals. After plotting the time-norepinephrine concentration curve, the area under the curve (AUC) in each group was calculated. RESULTS: In the mPOA, 30 and 60% Xe, but only 60% N(2)O significantly increased norepinephrine release. The AUC in the 30% Xe, 60% Xe or 60% N(2)O group was 160 +/- 9 (P <0.05), 288 +/- 42 (P <0.01) or 237 +/- 46 pg x min/sample (P <0.01), respectively, compared to that in the control group: 77 +/- 14 pg x min/sample. In the PH, only 60% Xe significantly increased norepinephrine release compared to control (AUC: 191 +/- 38 vs. 71 +/- 1 pg x min/sample, P <0.01). CONCLUSION: The present data suggest that Xe stimulates norepinephrinergic neurons more potently than N(2)O; 1.2 times more in the mPOA and 2.5 times more in the PH. This stimulant effect may contribute to the hypnotic and sympathotonic effects of Xe in rats.

Anesthetics, Inhalation↗

PubMedDate not supplied

Effects of thyrotropin-releasing hormone and phorbol ester on dopamine release from dispersed rat tuberoinfundibular dopaminergic neurons.

We have investigated the intracellular mechanisms underlying thyrotropin-releasing hormone (TRH)-mediated [3H]dopamine ([3H]DA) release from dispersed rat tuberoinfundibular dopaminergic (TIDA) neurons. The specific binding of [3H]Me-TRH to these cells is characterized by a single, high-affinity binding site (Kd = 1.2 nM) with a Bmax value of 178 fmol/mg protein. Thyrotropin-releasing hormone markedly increased [3H]DA release and intracellular free calcium concentration ([Ca2+]i) in TIDA neurons, and its effect was abolished by treatment with EGTA (5 mM) or chlordiazepoxide, a specific TRH receptor antagonist (10 microM). Furthermore, to examine the involvement of protein kinase C on [3H]DA release, we investigated the effect of phorbol myristate acetate (PMA), which is known to activate protein kinase C directly. Phorbol myristate acetate induced a significant increase in [3H]DA release in a concentration-dependent manner. Treatment with TRH (1 microM) plus PMA (100 nM) resulted in an additive increase in [3H]DA release. Thyrotropin-releasing hormone (1 microM) still increased [3H]DA release even after preincubation with PMA (500 nM) for 24 h, but PMA (100 nM) did not under the same conditions. These results suggest that TRH may induce DA release in dispersed rat TIDA cells by increasing calcium influx and activating the protein kinase C system.

Animals↗

PubMedDate not supplied

Facile method for the preparation of 7-methyl-8-oxoguanosines as an immunomodulator.

Reaction of 9-(2,3,5-tri-O-acetyl-beta-D-ribofuranosyl)-7-methylguaninium iodide (2a) with hydrogen peroxide in acetic acid gave the corresponding 7-methyl-8-oxoguanosine derivative (3a) in good yield. Deprotection of 3a easily gave 7-methyl-8-oxoguanosine (1), which is well-known as an immunomodulator. Substitution of acetyl group at the N2-position of guanine ring accelerated the oxidation reaction of the 7-methylguaninium iodide.

Adjuvants, Immunologic↗

PubMedDate not supplied

Tumor thrombus in the branches of the distal portal vein: CT demonstration.

Punctate and linear low density structures adjacent to the tumor nodules in the CT images of eight patients with hepatocellular carcinomas were followed for greater than 5 months to investigate the evolution of these low density structures. During the period of follow-up, patients were given anticancer therapy. Computed tomographic, angiographic, and autopsy examinations indicated that the CT finding of punctate or linear low density structures represented a tumor thrombus in the portal branches of the third and more distal orders. In two cases that showed punctate or linear low density structures adjacent to the distal side of the tumor nodules to the porta hepatis, a daughter nodule was detected by CT at 6.5 and 9.2 months, respectively, after the appearance of the low density structures. In two cases that showed punctate or linear low density structures adjacent to the proximal side of the tumor nodules to the porta hepatis, rapid and extensive tumor growth was found by CT at 5.4 and 8.0 months, respectively, after the appearance of the low density structures.

Aged↗

PubMedDate not supplied

Effect of Varidase (streptokinase) on biofilm formed by Staphylococcus aureus.

Staphylococcus aureus forms a fibrin-rich biofilm in the presence of plasma which is highly resistant to attack by the human immune system and to chemotherapy. Varidase, composed mainly of streptokinase, is used for hydrolyzing clots. In this study, we attempted to destroy the biofilm of S. aureus with Varidase and to apply this drug in the treatment of staphylococcal infections. Four clinical isolates were used in the experiments. These organisms formed a several-millimeter-thick biofilm on type IV collagen coated coverslips in trypticase soy broth containing 50% human plasma. The biofilm was composed of bacterial cell which adhered to fibrillar fibers and of sediment derived from plasma. 10,000 U/ml of Varidase, the dose which is used clinically, removed the sediment and reduced the number of live bacteria in biofilms to less than 20% of control. 200 U/ml of Varidase was also effective against biofilms of the organisms. An equal combination of Varidase and ofloxacin had an additive effect on the bacteria. The results of this study demonstrate that Varidase is highly effective in destroying biofilms of S. aureus in vitro and suggest that this drug would be useful for treating staphylococcal infections.

Biofilms↗

PubMedDate not supplied

Nigral degeneration in a case of amyotrophic lateral sclerosis: evidence of Lewy body-like and skein-like inclusions in the pigmented neurons.

This report describes a 58-year-old man who exhibited the clinical features of amyotrophic lateral sclerosis (ALS) at autopsy, 1 year after clinical onset of the disease. Neuropathologically, in addition to degeneration of the upper and lower motor neurons, marked degeneration of the substantia nigra with the appearance of Lewy body-like inclusions (LBI) and skein-like inclusions (SLI) were observed in the remaining pigmented neurons. An immunohistochemical study revealed that both LBI and SLI were immunopositive for ubiquitin. Ultrastructurally, LBI in the substantia nigra were composed of randomly arranged 15 nm thick tubular structures associated with ribosome-like granules, similar to those of LBI in the lower motor neurons. SLI in the substantia nigra were composed of curved bundles of 5 nm thick filaments (thinner than those comprising the SLI in the lower motor neurons). We believe that degeneration of the substantia nigra could be one of the degenerative processes involved in ALS.

Amyotrophic Lateral Sclerosis↗

PubMedDate not supplied

Primary hepatic choriocarcinoma--a case report.

A 65-year-old man experienced anorexia and abdominal enlargement and died suddenly 45 days after admission. Multiple necrotic and hemorrhagic tumors were present in the liver (6 kg). The fragile tumor ruptured and a large amount of blood accumulated in the peritoneal cavity. The tumor was composed of cytotrophoblast and syncytiotrophoblast cells. Neoplastic cells were positive for human chorionic gonadotropin and negative for alpha-fetoprotein and carcinoembryonic antigen. The huge tumor directly invaded the entire antrum of stomach. Neoplastic trophoblastic cells proliferated mainly in the serosa and propria muscular layer of the stomach, and tiny cancer nests were observed in many vessels of the submucosa and propria mucosa. The serum alpha and beta human chorionic gonadotropin subunits showed a very high level; 51 ng/mL and 820 ng/mL, respectively. No tumor, cyst or scar was observed in the testes, mediastinum and retroperitoneum, macroscopically and microscopically. Based on these autopsy findings, we diagnosed this patient as having primary hepatic choriocarcinoma.

Aged↗

PubMedDate not supplied

[Gastric vagotomy, fixation of the paries anterior and pyloroplasty as surgery in duodenal ulcer].

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Drainage↗