Extracellular H+ modulates acetylcholine-activated nonselective cation channels in guinea pig ileum

The effects of external H+ on the acetylcholine-induced inward current (nonselective cationic current; InsACh) in guinea pig ileal smooth muscle were investigated using the conventional whole cell patch-clamp technique. When the external pH (pHo) was lowered, the amplitude of InsACh was increased, with no significant change in the reversal potential or no detectable induction of other ionic permeabilities. The dose-response curve for this effect was best described by a Hill-type equation with an apparent pKa value of 7.4 and a Hill coefficient of approximately 1. The effect of pHo was associated with a shift of the steady-state activation curve for InsACh; the half-maximum activation potential became more negative on lowering pHo. Similar results were obtained when InsACh was activated by intracellularly applied guanosine 5'-O-(3-thiotriphosphate). These results indicate that the external H+ activity is an efficient regulator of InsACh channel, and this may have a physiological importance for controlling the muscarinic receptor-mediated contractions in this muscle.

ATP-hydrolyzing excitation state of the reconstituted alpha 3 beta 3 complex of ATP synthase from the thermophilic bacterium PS3: structural characteristics shown by time-resolved small-angle X-ray scattering with synchrotron radiation

The ATP-hydrolyzing excitation state of the alpha 3 beta 3 complex of the ATP synthase from the thermophilic bacterium PS3 was investigated using time-resolved small-angle X-ray scattering with synchrotron radiation. The results showed the presence of the alpha 3 beta 3 complex at a steady state during ATP hydrolysis when the alpha 3 beta 3 hexamer reacted with Mg-ATP. The radius of gyration of the complex in the steady state was significantly larger than that of the Mg-AMP-PNP-hexamer complex, indicating a conformational change to an expanded structure during catalysis. This alpha 3 beta 3 complex dissociated into alpha 1 beta 1 heterodimers with apparent first-order reaction kinetics after all the ATPs were converted to ADPs. In contrast, when the alpha 3 beta 3 complex reacted with Mg-ADP, the complex dissociated into dimers with apparent first-order reaction kinetics without showing the steady state of the complex. The dimers, however, re-associated into the hexamer when Mg-ATP was added. The results were well-explained by a computer simulation based on non-linear chemical dynamics, in which a reaction mechanism that incorporates the dynamic structure of the hexamer in the steady state was considered.

Effects of rat bile-pancreatic juice on Fe2+ induced peroxidation of phospholipids

The effects of rat bile-pancreatic juice (BPJ) on Fe2+ induced oxidation of soybean phosphatidylcholine (PC) was monitored to investigate the influence of this digestive juice on oxidative damage in the gastrointestinal tract. A large volume of BPJ (50% in the suspension of PC, v/v) suppressed the lipid peroxidation, but a smaller volume had the reverse effect. BPJ could decompose free fatty acid hydroperoxides (FFA-OOH) at a lower concentration (approximately 0.2 mM) completely, although its phospholipase activity liberated FFA-OOH from PC hydroperoxides. Sodium deoxycholate enhanced the Fe2+ induced oxidation of PC in a concentration-dependent manner when PC was suspended in the buffer. Boiled BPJ suppressed Fe2+ induced and peroxyl radical initiated oxidation of sodium deoxycholate micelles of soybean PC up to approximately 50% (v/v). It was strongly suggested that rat BPJ had a biphasic effect on Fe2+ induced oxidation of phospholipids depending on the enhancement by bile salts and the inhibition by antioxidant components with radical-scavenging activity and hydroperoxide-decomposing activity.

Enzymic method for the amperometric determination of nicotinic acid in meat products

An enzymic method for the determination of nicotinic acid is described, based on the indirect electrochemical monitoring of nicotinic acid via its reaction with oxygen in the presence of nicotinic acid hydroxylase. Derivative amperometric signals due to oxygen depletion enable a one-point kinetic analysis to be carried out. Nicotinic acid hydroxylase catalyses the hydroxylation of nicotinic acid to produce 6-hydroxynicotinic acid, which is accompanied by a stoichiometric consumption of oxygen. The method was applied successfully to the analysis of real samples.

Purification of (-)-epigallocatechin from enzymatic hydrolysate of its gallate using high-speed counter-current chromatography

Epigallocatechin gallate (EGCG) was hydrolyzed at various concentrations of tannase under pH 6.0 at 35 degrees C, and the reaction mixtures were separated by high-speed counter-current chromatography with a two-phase solvent system composed of hexane-ethyl acetate-water (1:13:20). The best results were obtained when 2 mg/ml of the enzyme buffer solution was added to 0.3 M EGCG buffers at a rate of 0.1 ml/min. Using 10 mg of the enzyme, 342 mg of epigallocatechin were obtained at a purity of 99.1%.

Portal vein aneurysm in the liver associated with multiple vascular malformations

Portal vein aneurysm (PVA) includes focal dilatation of the portal vein, and was formerly thought to be a rare disease. We report a 46-year-old man with chronic aggressive hepatitis and intrahepatic portal vein aneurysm communicating with the hepatic vein. Hemangiomas in the liver and intracranial arteriovenous malformation (AVM) were also found. To our knowledge, this is the first report of a case of PVA in a patient with congenital intracranial AVM. As the PVA in this patient communicated with the hepatic vein, and as hemangiomas in the liver and intracranial AVM were also present, the pathogenesis in this patient seems to have been congenital anomaly of the vasculature.

Effects of neonatal administration of zearalenone on the reproductive physiology of female mice

The effects of neonatal (1-10 days) administration of various doses (5-30 micrograms/animal) of zearalenone, a mycotoxin, on the sexual maturation and reproductive physiology of female ICR mice were investigated. The drug was found to have mimic estrogen actions, causing delayed vaginal opening, persistent estrus (60-80% incidence) and sterility. Daily doses of zearalenone (10-30 micrograms/animal) for 3-5 neonatal days resulted in infertility accompanied by thickening of the vaginal epithelium, even after ovariectomy and adrenalectomy, indicating mucosal independence of endogenous estrogen. Thus, it may be possible that zearalenone acts by binding irreversibly to estrogen receptors in the target tissues.

Clinical significance of minimal residual disease in leukemia detected by polymerase chain reaction: is molecular remission a milestone for achieving a cure?

Polymerase chain reaction (PCR) technology has been useful in clarifying molecular or minimal residual disease (MRD) status in patients with leukemia. Although PCR has several inherent problems, accumulated data have demonstrated that patients with leukemia harbor PCR-detectable residual disease for a certain period despite clinical remission. This has been for approximately 1 year in childhood acute lymphoblastic leukemia and adult acute promyelocytic leukemia after chemotherapy and for approximately 2 years in chronic myelogenous leukemia after bone marrow transplantation. Ultimately, PCR-undectable residual disease is necessary for achieving cures in most patients. However, it is difficult to make an early prediction of subsequent relapse after obtaining PCR negatively, since the emergence of PCR-detectable disease occurs only several months before clinical relapse. Therefore, PCR negativity is necessary but not sufficient for achieving cures in most patients with leukemia. Periods of persistent PCR-detectable disease will require further investigations for relapse prediction. More accurate serial quantitation would clarify a precise MRD status in leukemia patients and might allow for more accurate prediction of relapse. Since PCR-undectable residual disease is necessary for cures in most patients, it can be proposed that a "molecular remission", defined as PCR-undetectable disease, is a milestone and target for achieving cure by cytoreductive therapy.

Excitatory neurotransmission in the mammalian bladder and the effects of suramin

OBJECTIVE

To compare the electrical and mechanical activity, and assess the effect of suramin on strips of detrusor from various species.

MATERIALS AND METHODS

Bladder muscle strips from guinea-pigs, rabbits, monkeys and sheep and detrusor strips from humans (obtained at operation) were studied. The mechanical responses to nerve stimulation were recorded with a force transducer and electrical activity was recorded with the double sucrose gap.

RESULTS

In all species acetylcholine was released from the nerves and a prolonged contraction was produced. A second transmitter, possibly adenosine triphosphate, produced a rapid transient contraction, the amplitude of which varied with the species. In the rabbit and guinea-pig the phasic contraction and accompanying depolarization were large, whereas in primates they were small and in sheep were intermediate. At high concentrations, suramin reduced the contraction and accompanying depolarization in rabbit and guinea-pig muscle but not in sheep. Suramin enhanced the late cholinergic responses and increased spontaneous mechanical activity in all species. These latter effects were not seen after desensitization of the receptors with the ATP analogue alpha, beta- methylene ATP.

CONCLUSION

Although suramin reduces the excitatory effect of nerve activity in some species, it would produce little beneficial effect in the human hyperexcitable bladder as any inhibitory effect might be offset by the increase in spontaneous activity.

Fusion properties of cells constitutively expressing human parainfluenza virus type 4A haemagglutinin-neuraminidase and fusion glycoproteins

We established HeLa cell lines that constitutively expressed the fusion (F) and/or haemagglutinin-neuraminidase (HN) glycoproteins of human parainfluenza virus type 4A (PIV-4A) and used them to analyse the roles of these glycoproteins in virus-induced cell fusion. No syncytium formation occurred, even in HeLa cells expressing both the F and HN proteins (HeLa-4aF+HN cells). Also no syncytium was found in a mixed culture of cells expressing the F protein (HeLa-4aF) and the HN protein (HeLa-4aHN). Syncytia were observed in HeLa-4aF cells transfected with the HN gene, but no syncytium formation was found in HeLa-4aHN cells transfected with the F gene. Co-cultivation of HeLa-4aF+HN cells with HeLa-4aF cells generated large polykaryocytes, whereas co-cultivation with HeLa-4aHN cells induced no cell fusion. Infection of HeLa-4aF cells with PIV-4A generated large syncytia and degenerated nuclei, whereas little or no polykaryocytes were found in HeLa-4aHN cells infected with PIV-4A. From the above findings, the following conclusions were drawn: (i) the expression of both the F and HN proteins in the same cell is necessary for cell fusion; (ii) the expression of the F protein alone enhances susceptibility to cell fusion; (iii) the constitutive expression of the HN protein promotes resistance to paramyxovirus-induced cell fusion.

Alternative treatment may lower the need for use of extracorporeal membrane oxygenation

Access to artificial surfactant and high frequency oscillatory ventilation (HFO) in Japan seems to affect the actual indications for extracorporeal membrane oxygenation (ECMO). The relation between the methods of treatment and survival and/or neurological sequelae of 27 neonates with severe respiratory failure who would have met the US ECMO entry criteria in the Neonatal Intensive Care Unit of National Children's Hospital, Tokyo between January 1988 and May 1992 were retrospectively analyzed. Out of 27 neonates, conventional treatment including artificial surfactant was successful in 6 cases (22%). High frequency oscillatory ventilation was used for the 21 cases who did not respond to conventional treatment and it was effective in 5 cases (19% of total). Extracorporeal membrane oxygenation was used on 11 (40% of total) of 16 cases who did not respond to HFO. Eight (29% of total or 73% of ECMO cases) of these cases survived and 3 cases (11% of total) died. The remaining 5 cases (19% of total) who met the exclusion criteria of ECMO died. No patient with respiratory distress syndrome (RDS) became ill enough to meet the US ECMO entry criteria. Six out of 8 congenital diaphragmatic hernia cases were saved on a delayed surgery protocol with HFO. Only about 1% of the neonates who were admitted to our NICU during the last 4 years needed ECMO treatment. Forty-one per cent of the patients who would have met the US ECMO entry criteria were treated successfully without ECMO. The necessity for ECMO is less in Japan than in the US because other methods can often be used successfully to treat severe respiratory disorders.

Colonic lysozymes of rabbit (Japanese white): recent divergence and functional conversion

Lysozyme was extracted from the feces of rabbit (Japanese White) with 2.5% acetic acid and purified by ion-exchange chromatography. Subsequent ion-exchange HPLC at pH 4.0 revealed the presence of two isozymes, namely rabbit colonic lysozymes 1 and 2. The amino acid sequences of these lysozymes were determined. The colonic lysozymes 1 and 2 showed 98% identity with each other and 94 and 95% identities with rabbit kidney lysozyme, respectively. The very high identities between kidney and colonic lysozymes indicate that the colonic isozymes diverged from the conventional kidney lysozyme very recently, probably after the divergence of rabbit from other rodents, accompanying the gene duplication. Despite the small changes in the sequences, the enzymatic properties of colonic lysozyme differ from those of the kidney lysozyme. The activity of the colonic lysozyme against Micrococcus luteus cells showed a narrow and acidic pH optimum, in contrast to the wide and high pH optimum of the kidney lysozyme. Changes in the enzymatic properties are analogous to those of the ruminant stomach lysozymes and may implicate adaptive evolution in the functional conversion of rabbit colonic lysozymes in gut.

Preparative separation of stereoisomeric 1-methyl-4-methoxymethylcyclohexanecarboxylic acids by pH-zone-refining counter-current chromatography

The application of pH-zone-refining counter-current chromatography (CCC) to the preparative separation of stereoisomeric acids is described. The separation was accomplished on the basis of the difference in acidity of the two stereoisomers. pH-Zone-refining CCC of 400 mg of a crude synthetic mixture of stereoisomeric 1-methyl-4-methoxymethylcyclohexanecarboxylic acids yielded 49.5 and 40 mg of the pure Z- and E-stereoisomers respectively. The two-phase solvent system consisted of hexane-ethyl acetate-methanol-water (1:1:1:1). Trifluoro acetic and octanoic acids were used as retainer acids. The eluent base was aqueous ammonia. The eluted fraction were monitored by gas chromatography-mass spectrometry.

Separation of alkaloids by pH-zone-refining counter-current chromatography

pH-Zone-refining counter-current chromatography was applied to the separation of alkaloids from a crude extract of Crinum moorei using a multilayer coil planet centrifuge. After methyl tert.-butyl ether and water were equilibrated, triethylamine (5-10 mM) was added to the organic phase and hydrochloric acid (5-10 mM) to the aqueous phase. The separation was performed by eluting the column with either the organic phase (displacement mode) or the aqueous phase (reverse-displacement mode) while the other phase was used as the stationary phase. From 3 g of the extract, crinine, powelline and crinamidine were separated in 2.5-7 h with minimum overlapping.

Necrotizing arteritis causing fatal massive intraperitoneal hemorrhage from a pancreatic pseudocyst

We report the histopathological findings from a medicolegal autopsy case caused by sudden massive hemorrhage from a necrotic pancreatic cyst into the abdominal cavity. The histological examination revealed that the wall of the cyst was filled with hematoma and consisted of granuloma at a relative early stage, involving marginating lymphocytes, foamy lipophages, cholesterin crystals, foreign body giant cells with neutrophiles, mast cells and fibrous tissues. Since there was no epithelial lining, the lesion was diagnosed as a pseudocyst. In the wall of this pseudocyst, small arteries showed acute intense necrotizing inflammatory reactions in association with fresh thrombi. Trace of elastic fibers remained in the wall of the arteries. Since the small veins in the wall showed varix-like changes without necrosis or inflammation, it is proposed that the lethal bleeding was caused by rupture of the small arteries that exhibited severe arteritis.

gamma delta T cells play a crucial role in the expression of 65,000 MW heat-shock protein in mice immunized with Toxoplasma antigen

Toxoplasma gondii is an obligate intracellular protozoan parasite and cellular immunity plays a crucial role in protection against infection with this pathogen. When mice are immunized with Toxoplasma homogenate, they readily acquire resistance against infection with a lethal dose of a low virulence Beverley strain of T. gondii. We have reported previously that expression of 65,000 MW heat-shock protein (hsp 65) in host macrophages closely correlates with protective potentials of hosts, while this protein is not expressed in Toxoplasma themselves. In this study, we examined the mechanism of expression of hsp 65 in mice immunized with Toxoplasma homogenate. Heat-shock protein was detected in peritoneal macrophages of BALB/c mice immunized 7 days previously by electroblot assay with a specific monoclonal antibody (mAb) for microbial hsp 65. Furthermore, an immunogold ultracytochemistry assay demonstrated that this protein was expressed on the cell surface of peritoneal macrophages in immune mice. This expression was not induced in those of immune athymic nude mice and SCID mice. Treatment of BALB/c mice with anti-Thy-1.2 mAb 1 day before immunization led to an almost complete loss of the expression of hsp 65. To determine the subsets of T cells responsible for induction of this protein, mice were depleted of gamma delta T cells, alpha beta T cells, CD4+ T cells or CD8+ T cells by treating with corresponding antibodies before immunization. From these experiments, gamma delta T cells were shown to be essential for the expression of hsp 65, although CD4+ alpha beta T cells also contributed to some extent. Thus, gamma delta T cells appear to play an important role in protective immunity against infection with T. gondii through mediating the expression of hsp 65 in host macrophages.

Expression of the c-met protooncogene in human hepatocellular carcinoma

The c-met protooncogene is a growth factor receptor with tyrosine kinase activity. Recently the hepatocyte growth factor was identified as the ligand for this receptor. Because the hepatocyte growth factor is a most potent mitogen in hepatocytes, possible involvement of c-met expression in hepatocarcinogenesis is suspected. In this study, we examined c-met expression in 23 hepatocellular carcinoma cases by means of Northern-blot analysis and an immunohistochemical study. Northern-blot analysis revealed c-met mRNA expression in the tumors of 6 of 19 patients (31.6%); in the immunohistochemical study, c-met protein was detected in 16 of 23 patients (69.6%). With both methods, c-met was found to be overexpressed in hepatocellular carcinoma compared with the surrounding normal liver. Comprehensive analysis showed that c-met protein expression was correlated with poor-to-moderate differentiation of cancer cells (p < 0.05). Tumor proliferative activity of hepatocellular carcinoma was evaluated by means of Ki-67 labeling index. All cases with increased tumor proliferative activity showed c-met protein expression, although the elevation of proliferative activity in the c-met-positive group was not statistically significant. These data suggest that the overexpression of c-met plays an important role in the development of hepatocellular carcinoma.

A study on left atrial transport function. Effect of age or left ventricular ejection fraction on left atrial storage fraction

Left atrial (LA) storage fraction is defined as the ratio of storage volume of the left atrium (LA) during ventricular systole to left ventricular (LV) stroke volume. To test their hypothesis that left atrial (LA) storage fraction is increased to compensate for impaired LV filling in the heart of aged subjects or with impaired LV ejection fraction, the authors studied 33 "normal" subjects and 25 patients with coronary artery disease. LA volume was measured by LA cineangiocardiography, and LV stroke volume and LV ejection fraction were measured by LV cineangiocardiography. To further evaluate the determinants of changes in LA storage fraction, they measured the ratio of LA active release volume to LV stroke volume, and the ratio of LA passive release volume to LV stroke volume. In "normal" subjects, LA storage fraction was increased with age (r = 0.584, P < 0.01). In patients with coronary artery disease, LA storage fraction was increased as LV ejection fraction was decreased (r = -0.525, P < 0.01). In both cases, LA active release fraction was significantly associated with changes in LA storage fraction rather than in LA passive release fraction. They conclude that LA storage fraction may be an important determinant of LV filling mainly through the LA active release fraction.

Carrier-mediated transport of H1-antagonist at the blood-brain barrier: a common transport system of H1-antagonists and lipophilic basic drugs

The blood-brain barrier (BBB) transport system for H1-antagonists was studied using primary cultured bovine brain capillary endothelial cells (BCEC). The uptake of [3H]mepyramine was inhibited by various H1-antagonists. Ketotifen competitively inhibited [3H]mepyramine uptake with an inhibition constant (Ki) of 46.8 microM. Lipophilic basic drugs such as propranolol, lidocaine and imipramine significantly inhibited [3H]mepyramine uptake. In particular, propranolol inhibited [3H]mepyramine uptake competitively at an inhibition constant (Ki) of 51.1 microM. Moreover, in ATP-depleted BCEC, [3H]mepyramine uptake was stimulated by preloading with H1-antagonists and lipophilic basic drugs. These results indicated that H1-antagonists are transported across the BBB via a carrier-mediated transport system common to lipophilic basic drugs.