The role of chloroplastic NAD(P)H dehydrogenase in photoprotection

After a brief exposure to supra-saturating light, leaves of a tobacco transformant, in which chloroplastic NAD(P)H dehydrogenase (NDH) was defective, showed more severe photoinhibition than the wild-type, when judged by the parameter of chlorophyll fluorescence Fv/Fm. Repeated application of supra-saturating light eventually resulted in chlorosis in the NDH-defective mutant, while the wild-type sustained less photodamage and was able to recover from it. The mechanism of the phenomena is discussed with respect to the potential role of NDH in photosynthesis.

Induction of smooth muscle cells in the fibrous capsule of human hepatocellular carcinoma but not in the septa of hepatic cirrhosis

We examined the expression of smooth muscle cytoskeleton in spindle-shaped cells in the capsule of hepatocellular carcinoma (HCC) and the septa of liver cirrhosis (LC). Serial sections of livers resected from 11 patients were stained with monoclonal antibodies against vimentin, desmin, smooth muscle actin (1A4, HHF35, CGA7) and smooth muscle myosin heavy chain isoforms (SM1, SM2). Capsular spindle-shaped cells exhibited a cytoskeletal feature indicative of intermediately differentiated smooth muscle cells. Computer-assisted morphometry revealed that the proportions of 1A4-, HHF35-, CGA7- and SM1- positive areas to vimentin-positive area were 88.0+/-11.0%, 50.8+/-17.4%, 25.3+/-16.4% and 19.4+/-12.4% (n=11) in main tumours and 86.6+/-9.4%, 50.9+/-18.7%, 21.1+/-12.3% and 17.6+/-9.7% (n=12) in daughter tumours, indicating that spindle-shaped cells are heterogeneous in cytoskeletal expression. Septal spindle-shaped cells in LC lacked the cytoskeletal proteins specific to differentiated smooth muscle cells (CGA7, SM1, SM2 and desmin). Electron microscopically, capsular spindle-shaped cells contained more microfilaments and less rough endoplasmic reticulum than do septal cells. Intermediately differentiated smooth muscle cells are induced in the capsule of HCC but not in the septa of LC, suggesting a role for stromal interaction by tumour cells in the induction of smooth muscle cells.

Effects of linear acceleration on fish behavior and eye movements

Behavioral responses and eye movements of fish during linear acceleration were reviewed. It is known that displacement of otoliths in the inner ear leads to body movements and/or eye movements. On the ground, the utriculus of the vestibular system is stimulated by otolith displacement caused by gravitational and inertial forces during horizontal acceleration of whole body. When the acceleration is imposed on the fish's longitudinal axis, the fish showed nose-down and nose-up posture for tailward and noseward displacement of otolith respectively. These responses were understood that the fish aligned his longitudinal body axis in a plane perpendicular to the direction of resultant force vector acting on the otoliths. When the acceleration was sideward, the fish rolled around his longitudinal body axis so that his back was tilted against the direction in which the inertial force acted on the otoliths. Linear acceleration applied to fish's longitudinal body axis evoked torsional eye movement. Direction of torsion coincided with the direction of acceleration, which compensate the change of resultant force vector produced by linear acceleration and gravity. Torsional movement of left and right eye coordinated with each other. In normal fish, both sinusoidal and rectangular acceleration of 0.1G could evoke clear eye torsion. Though the amplitude of response increased with increasing magnitude of acceleration up to 0.5 G, the torsion angle did not fully compensate the angle calculated from gravity and linear acceleration. Removal of the otolith on one side reduced the response amplitude of both eyes. The torsion angle evoked by rectangular acceleration was smaller than that evoked by sinusoidal acceleration in both normal and unilaterally labyrinthectomized fish. These results suggest that eye torsion of fish include both static and dynamic components.

Prognostic significance of angiogenesis in human pancreatic cancer

To evaluate whether angiogenic factors are of clinical relevance to actual human pancreatic cancers, we studied the intratumoral microvessel density (IMD), and PD-ECGF, VEGF protein expression in 40 pancreatic cancers using immunohistochemistry. We also investigated PD-ECGF and VEGF gene expression using reverse transcriptase-PCR (RT-PCR). Of the 40 pancreatic cancers studied, 30 carcinomas (75.0%) were evaluated to be PD-ECGF-positive and 10 carcinomas (25.0%) were determined to be PD-ECGF-negative. In contrast, 27 carcinomas (67.5%) were evaluated to be VEGF-positive, whereas 13 carcinomas (32.5%) were VEGF-negative. VEGF gene expression was moderately associated with an increase in the IMD (r2 = 0.181, P = 0.006), but no significant relationship was found between PD-ECGF gene expression and the IMD (r2 = 0.093, P = 0.059). However, tumours with positive expression for both PD-ECGF and VEGF had a higher IMD (P = 0.027). The results of the immunohistochemistry agreed well with the results of the quantitative RT-PCR. The median survival time of the hypervascular group was significantly shorter than that of the hypovascular group (P < 0.0001). In comparing the survival according to PD-ECGF and VEGF gene expression, the median survival time of the patients with positive PD-ECGF expression was significantly shorter than those with negative PD-ECGF expression (P = 0.040). Furthermore, the median survival time of the patients with positive VEGF expression was significantly shorter than those with negative VEGF expression (P = 0.048). However, the Cox multivariate analysis indicated that the IMD and VEGF expression were independent prognostic factors of the various clinicopathologic variables in pancreatic cancer patients (P = 0.0021 and P = 0.0443, respectively).

Cutting edge: dominant effect of Ile50Val variant of the human IL-4 receptor alpha-chain in IgE synthesis

Two variants of the IL-4R alpha-chain (IL-4Ralpha) gene have been recently identified in association with different atopic disorders. To clarify the etiological relationship between the two variants, we analyzed responsiveness to IL-4 of transfectants with four kinds of IL-4Ralpha carrying either Val or Ile at 50 and either Gln or Arg at 551. The substitution of Ile for Val augmented STAT6 activation, proliferation, and transcription activity of the Iepsilon promoter by IL-4, whereas that of Arg for Gln did not change these IL-4 signals. Arg551 was not associated with atopic asthma in the Japanese population. CD23 expression and IgE synthesis by IL-4 were augmented in Ile50-bearing PBMC, compared with those bearing Val50. Taken together, substitution of Arg551 does not enhance the IL-4 signal for generation of germline epsilon transcript, whereas the substitution of Ile50 contributes to enhancement of IgE synthesis.

Redox regulation of caspase-3(-like) protease activity: regulatory roles of thioredoxin and cytochrome c

Oxidative stress induces a variety of cellular responses, including apoptosis, and caspase family proteases are known to be involved in apoptosis. Caspase-3(-like) protease activity was examined in Jurkat T cells to investigate the mechanism of apoptosis induced by a thioloxidant, diamide. Caspase-3 was activated when cells were cultured with 200 microM diamide that induced apoptosis, whereas no caspase-3 activation was detected with 500 microM diamide that induced necrosis. When apoptosis was induced in cells with exposure to 200 microM diamide, the intracellular thioredoxin (TRX) levels were maintained and the intracellular generation of reactive oxygen intermediates was marginal. The cytosolic fractions of cytochrome c were increased earlier than the activation of caspase-3. In contrast, when cells were exposed to 500 microM diamide, intracellular reactive oxygen intermediate generation was increased and processing of caspase-3 was not detected despite cytochrome c release, resulting in necrosis. Caspase-3 activity in cell lysate precultured with anti-Fas Ab was suppressed dose dependently by diamide and restored by thiol-reducing agents, DTT or TRX. When cells were precultured with 5 mM of buthionine sulfoximine, an inhibitor of glutathione synthesis, intracellular TRX levels were maintained, and as low as 20 microM diamide could induce apoptosis associated with the increase of cytosolic cytochrome c and the activation of caspase-3. These results indicate that the activation of caspase-3 in diamide-induced apoptosis is mediated, at least partly, by cytochrome c release from mitochondria, and the cellular reducing environment maintained by TRX, as well as glutathione, is required for caspase-3 activity to induce apoptosis.

Accumulation of stress protein 72 (HSP72) in muscle and spleen of goldfish taken into space

Using Western blot analysis, here, we report the levels of HSP72 in several organs from goldfish which were taken into space on the NASA space shuttle. A remarkable accumulation of HSP72 was detected in muscle and spleen of those fish taken into space as compared with controls. These results suggested that the HSP72 induction is a kind of stress response at the molecular level introduced by the space environment consisting of microgravity and/or cosmic radiation as stressors.

Mechanism of vestibular adaptation of fish under microgravity

In a space experiment, the adaptation of goldfish behavior during flight and readaptation after landing were investigated. Six goldfish (1 normal, 1 with otoliths removed on both sides, 4 with otoliths removed on one side) were flown in a fish package (F/P) of Aquatic Animal Experiment Unit (AAEU). The dorsal light responses (DLRs) of fish with otoliths removed were recorded after operation until launch and after landing. The behaviors of the fish were recorded with a video camera on Mission Elapsed Time (MET) Day-00, 02, 05, 08, 12. On MET Day-00, two fish with otoliths removed on one side showed flexion of body toward the operated side. These fish also showed rolling behavior toward the operated side. However, the body flexion disappeared on MET Day-05 or MET Day-08. No rolling behaviors were observed after that time. Five fish showed backward looping behaviors during the mission. Although the frequency of looping episodes decreased after MET Day-08, five fish still showed looping behavior on MET Day-12, that was the last day of video recording on orbit. In microgravity, visual system of fish did not seem to provide sufficient cues to prevent them from looping or rolling. After landing, no looping and rolling behavior was observed. However, the tilt angle of the DLR increased in the fish with otolith removed 5 month before launch but not in normal fish and those with otoliths removed 2 weeks before launch. These results suggest that the behavioral dysfunction and the adaptational process in space are dependent on vestibular inputs.

Breast milk is not a significant source for early Epstein-Barr virus or human herpesvirus 6 infection in infants: a seroepidemiologic study in 2 endemic areas of human T-cell lymphotropic virus type I in Japan

In order to evaluate the possibility of Epstein-Barr virus (EBV) and human herpesvirus 6 (HHV-6) transmission via breast milk, a total of 331 serum specimens collected from bottle-fed and breast-fed children and their mothers, in 2 endemic areas of human T-cell lymphotropic virus type I (HTLV-I) in Japan, were assayed for antibodies to EBV and HHV-6. The seroprevalences of EBV and HHV-6 were over 95% both in the mothers of bottle-fed children and in those of breast-fed children. The seroprevalence of EBV at 12-23 months of age was 54.5% (36/66) and 55.8% (24/43) in breast-fed children and bottle-fed children, respectively. The seroprevalence of HHV-6 at 12-23 months of age was 90.9% (60/66) and 93.0% (40/43) in breast-fed children and bottle-fed children, respectively. No difference was observed between the seroprevalences of EBV and HHV-6 in breast-fed and bottle-fed children at 12-23 months of age. Our seroepidemiologic data indicate that breast milk is not a significant source of early EBV or HHV-6 infection in infancy.

Redox control of resistance to cis-diamminedichloroplatinum (II) (CDDP): protective effect of human thioredoxin against CDDP-induced cytotoxicity

Thioredoxin is a small ubiquitous protein with multiple biological functions, including cellular defense mechanisms against oxidative stress. In the present study, we investigated the role of human thioredoxin (hTRX) in the acquisition of cellular resistance to cis-diamminedichloroplatinum (II) (CDDP). The expression and activity of hTRX in Jurkat T cells was dose-dependently enhanced by exposure to CDDP, as determined by immunoblot analysis and insulin reducing assay. Furthermore, chloramphenicol acetyltransferase analysis using the hTRX promoter-reporter gene construct revealed that treatment of Jurkat cells with CDDP caused transcriptional activation of the hTRX gene, which might be mediated through increased generation of intracellular reactive oxygen intermediates. To examine the biological significance of hTRX induction, we established hTRX-overexpressing derivatives of L929 fibrosarcoma cells by stable transfection with the hTRX cDNA. The clones, which constitutively expressed the exogenous hTRX, displayed increased resistance to CDDP-induced cytotoxicity, compared with the control clones. After exposure to CDDP, the control cells showed a significant increase in the intracellular accumulation of peroxides, whereas the hTRX-transfected cells did not. Taken together, these results suggest that overexpressed hTRX is responsible for the development of cellular resistance to CDDP, possibly by scavenging intracellular toxic oxidants generated by this anticancer agent.

Evidence of sensory conflict and recovery in carp exposed to prolonged weightlessness

BACKGROUND

Evidence in support of the sensory conflict hypothesis for space motion sickness (SMS) is still needed.

HYPOTHESIS

We hypothesized that sensory conflict and recovery processes should be demonstrated in intact fish during initial days of microgravity exposure, as a disturbance and restoration of the dorsal light response (DLR; a functional model of visual-graviceptor interaction), respectively. We also expected that this would be true in an otolith-removed fish if it had been fully compensated for dysfunction before the exposure.

METHODS

The DLR of carp (Cyprinus carpio) was examined intermittently during the 8-d mission of Spacelab-J. Two carp, normal and labyrinthectomized (LB), made the flight.

RESULTS

In the normal carp, the DLR was unstable for the first 3 d inflight but gradually recovered thereafter. The recovery was characterized by gradual restoration of the DLR tilt speed. The LB fish whose otoliths had been removed 2 mo before the flight maintained DLR at the first inflight test session (22 h after launch), but DLR was disrupted at 2 d as in normal fish. The recovery process could not be evaluated in this fish, because the EEG cable which was attached to the fish for supplementary study became tightly twisted and thus immobilized the fish for the remainder of the experiment.

CONCLUSION

These findings provided additional evidence in fish for sensory-motor disorder and readjustment during the early phase of microgravity, thus supporting the sensory conflict hypothesis for SMS.

The looping behavior of fish in microgravity

Fish subjected to microgravity during space flight were monitored for their swimming behavior, particularly the looping response. Experiments were performed on normal fish, unilaterally labyrinthectomized fish, and bilaterally labyrinthectomized fish. Observation were compared against the behavior of other species which had been evaluated in microgravity during parabolic flight.

Biliary haptoglobin, a potent promoter of cholesterol crystallization at physiological concentrations

BACKGROUND/AIMS

Several proteins present in human bile have been reported to promote cholesterol crystallization and thus are potentially important in the formation of cholesterol crystals as the initial stage in gallstone pathogenesis. To be physiologically relevant, such proteins must either be present in high concentration in bile or have a potent promoting activity. The current study explored several of the more abundant but unexamined biliary proteins based upon their also having sufficiently high serum concentrations that antibodies were available for both their isolation and quantitation.

METHODS

Protein purification was accomplished by immunoaffinity chromatography of bile followed by delipidation. Con A affinity chromatography of bile was used to obtain the bound fraction, a portion of which was delipidated. Crystallization-promoting activity of both the purified proteins and Con A-bound glycoprotein fractions (CABG) was measured by a photometric crystal growth assay. A competitive antibody-capture ELISA assay was developed to measure concentrations of alpha 1-antitrypsin, transferrin, and haptoglobin in native bile.

RESULTS

At their relevant physiological concentrations, biliary haptoglobin (15 micrograms/ml) had a crystallization-promoting activity twice that of the biliary IgM (75 micrograms/ml) used as a reference standard (P < 0.05). Biliary transferrin (20 micrograms/ml) had only modest promoting activity (P < 0.05). Biliary alpha 1-antitrypsin (50 micrograms/ml), by contrast, showed no promoting activity. Delipidation of the CABG fraction decreased its promoting activity by 75%. Biliary haptoglobin accounts for about 30% of delipidated total CABG-promoting activity.

CONCLUSIONS

Biliary haptoglobin at its physiological concentration has a highly potent crystallization-promoting activity and thus becomes a candidate for major attention in understanding gallstone pathogenesis.(ABSTRACT TRUNCATED AT 250 WORDS)

The ratio of reduced glutathione/oxidized glutathione is maintained in the liver during short-term hepatic hypoxia

Controversy persists as to whether reperfusion-induced injuries actually occur in the hepatocyte. The liver is the major source of glutathione, a scavenger of hydrogen peroxide. The aim of this study was to evaluate the sensitivity of the ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG) [GSH:GSSG] as an index of hepatic metabolic stress. A total of 121 rats were studied. The superior mesenteric vein (SMV) was occluded for 30 min, and this was followed by 0, 10, or 120 min of reperfusion. Total glutathione and GSSG levels in the liver, bile, and plasma were quantified, using glutathione reductase-coupled enzymatic assays. Results indicated that the hepatic GSH/GSSG ratio was maintained after an occlusion of the SMV, despite a decrease in adenosine triphosphate (ATP) level and energy charge potential. However, plasma levels of total glutathione and GSSG in the inferior vena cava increased after SMV occlusion and continued to increase after reperfusion. Biliary GSSG efflux decreased during 30-min occlusion of the SMV, and remained low even after reperfusion. The liver maintains homeostasis despite a decrease in biliary GSSG efflux, probably by secreting excess GSSG into the hepatic vein when the SMV is occluded. We conclude that the total amount of glutathione and GSSG in the plasma is directly correlated with oxidative stress in the liver.

Recurrent splenic artery aneurysms developing after aneurysmectomy without splenectomy: report of a case

We report herein the case of a 47-year-old man who developed a huge splenic artery aneurysm (SAA) with splenomegaly, for which ligation of the splenic artery and partial aneurysmectomy was performed. A celiac arteriogram taken 2 months postoperatively revealed that two small aneurysms had developed in the collateral vessels, indicating that increased blood flow through the collateral circulation could be responsible for the formation of secondary aneurysms. This postoperative change suggests that the etiology is related to the SAA and thus, the possibility that aneurysms may develop in the collateral vessels following spleen-preserving procedures for SAA must be borne in mind and careful follow-up performed at regular intervals.

Complete obstruction of the inferior vena cava due to chronic relapsing pancreatitis: a case report

A woman aged 62 with long history of chronic relapsing pancreatitis presented with swelling and ulcer in the lower limbs and occasional gastrointestinal bleeding. The radiological imaging showed complete obstruction of Inferior Vena Cava (IVC) at the level of the pancreas and well developed collateral vessels. Portal vein and splenic vein were also obstructed and superior mesenteric venous blood drained into the liver via coronary vein. She was originally found to have pancreas head tumor, which was not resectable. A palliative operation was performed, but histological examination of pancreatic specimen suggested only chronic inflammation and no evidence of malignancy. She was diagnosed as tumor-forming type chronic pancreatitis. Although SPV or SMV-PV obstruction has been recognized as a complication of chronic pancreatitis, IVC obstruction can occur by the same mechanism. This is the only case but one ever reported. Not only splenoportography but IVC-graphy will contribute to more precise understanding of patient's condition with chronic pancreatitis.

Space experiment using large-sized fish: in case of carp in Spacelab-J mission

Two carp of 26 cm in size, intact and otolith-removed (LB), were flown on the Spacelab-J for 8 days in September 12-20, 1992. Light-dependent reaction to alternating direction of illumination was recorded for 10 min twice a day together with the cerebellar EEG activity, on 2 days before the launch, during the flight and for 4 days after the landing, in same fish chamber. Reproducing the video image, it was revealed that both carp were healthy during the mission, but the LB fish was almost immobilized from the 3rd test session (48 hours in flight) by tight twisting of the EEG cable. Both fish after landing tended to stay still on the bottom of the fish chamber. Findings that the body weight reduced remarkably in both fish and that nitrite and nitrate levels of the fish water were usually high, suggested that the fish metabolism might have been enhanced during the flight.

Isolation of a human biliary glycoprotein inhibitor of cholesterol crystallization

BACKGROUND

About 50% of populations in developed countries have bile supersaturated with cholesterol, which is a major risk factor for cholesterol gallstone formation. Despite the prevalence of supersaturated bile, only about 10% of these populations develop gallstones. The existence of a biliary protein that inhibits cholesterol crystallization was hypothesized to explain this discrepancy. This report outlines the purification and characterization of such a human biliary glycoprotein.

METHODS

Chromatographic methods were used for separation and characterization. Additional steps included activity analysis by crystal growth assay, electrophoresis, and deglycosylation.

RESULTS

The glycoprotein consists of a heterodimer, M(r) of 120 kilodalton, with subunits of M(r) of 63 kilodalton and 58 kilodalton. Each of the subunits is characterized by an isoelectric point of 6.6 and shows comparable inhibitory activity. Deglycosylation of the subunits show that they share a similar polypeptide backbone (M(r) of 35 kilodalton) based upon a highly similar amino acid profile. This suggests that differential subunit glycosylation alone may account for the apparent heterodimeric structure.

CONCLUSIONS

No other human biliary glycoprotein has been found thus far that shows cholesterol crystal growth-inhibiting activity. Thus, it may be of importance in preventing gallstone formation in healthy populations.

Postural control of fish related to gravity input

The disappearance of gravity input during space flight causes many functional disorders in animal and human postural control system. On the other hand, it has been shown that these functional deficits reduce or disappear with time and adapt to weightlessness. Unusual fish behavior was reported during the first few days of orbit flight and also during postflight recovery in Skylab 3 experiment. Similar fish behavior was observed in microgravity obtained during the parabolic flight of airplane. These results suggest that fish might provide a good model for investigating adaptation of sensory-motor interaction in microgravity. The fish generally show a "dorsal light response (DLR)" indicating how these postural mechanisms concern with the environment. That is, when a light is presented laterally, a fish rolls its dorsal surface toward the light an equilibrium point between the gravity vector and the light source vector. In addition, the DLR after bilaterally labyrinthectomy or changes of the DLR in microgravity show the involvement of other factors related to the changes of gravity. In this investigation, the behavioral changes of bilaterally labyrinthectomized (BL) and unilaterally labyrinthectomized (UL) fish adapted for more than 3 months on the ground postoperatively were used to analyze whether buoyancy was affected by injecting of a contrast medium into the swimming bladder.