Age-related changes in the brains of senescence-accelerated mice (SAM): association with glial and endothelial reactions

Twelve substrains of inbred senescence-accelerated mice (SAM) have been developed, among which the SAMP8 and SAMP10 strains show a significant age-related deterioration in learning and memory for passive and active avoidance tasks. These strains have, respectively, a low and high incidence of systemic senile amyloidosis. Although we found no amyloid deposits in their brain parenchyma, a variety of age-related alterations were identified, involving neurons, glia, and vessels in the brain tissues. Here we review the degenerative changes in aged SAMP8 and SAMP10 brains. These changes are generally similar to the pathology of aging human brain and may be characterized by their association with some specific glial reactions.

An early stage mechanism of the age-associated mitochondrial dysfunction in the brain of SAMP8 mice; an age-associated neurodegeneration animal model

In order to characterize the early stage of mitochondrial dysfunction, we investigated the redox state and oxidative phosphorylation of the brain mitochondria from 2-month-old Senescence-accelerated mouse (SAM)P8 and SAMR1 mice; SAMP8 mice exhibit various signs of age-associated neurodegeneration and rapid mitochondrial dysfunction, although SAMR1 mice do not. The redox state was estimated as the reduction rate of Cu-pyruvaldehyde-bis (N4-methylthiosemicarbazone) (Cu-PTSM), the reduction of which is closely related to the electron leakage from the mitochondrial electron transport system in the brain, using electron spin resonance spectrometry (ESRS). The oxidative phosphorylation was measured polarographically. The SAMP8 mouse brain mitochondria demonstrated higher redox state and a higher activity of mitochondrial respiration with lower respiration control ratio than the mitochondria of SAMR1 mouse brains. This indicates that an inefficient hyperactive state can exist in the mitochondrial electron transport system before the age-associated mitochondrial dysfunction develops.

Does AK-2123 (Senazole) have sensitizing effects on radiation, cisplatin and hyperthermia under aerobic conditions in vitro?

We investigated the sensitizing effects of AK-2123 (Senazole) on the interaction of radiation, cisplatin and hyperthermia under aerobic conditions in the rat yolk sac cell line NMT-1R in vitro. The effects were assessed by clonogenic assay. A cytotoxic effect of AK-2123 after 24 hours exposure was observed as a function of the dose. For NMT-1R cells, the ID70 of AK-2123 was 400 micrograms/ml for 24 hours exposure, which was employed for subsequent combined treatments. Although a statistically significant increase in the G1 cell fraction was observed after AK-2123 treatment with a dose of ID70 (p = 0.02) no enhancing effect of AK-2123 on radiation, cisplatin or heat response curves was detected under aerobic conditions in vitro.

Protective effect of rebamipide against ammonia-induced gastric mucosal lesions

We investigated the protective effect of rebamipide against ammonia-induced gastric mucosal lesions. Participation of prostaglandin E2 and nitric oxide in the action of rebamipide was also examined. Rebamipide was administered intraperitoneally (10-100 mg/kg) to male Wistar/ST rats (150-325 g) fasted for 24 hr. Thirty minutes later, 1% NH4OH (1 ml) solution was given intragastrically. One hour later, the length of the mucosal lesions was measured (lesion index), and prostaglandin E2 (PGE2) was determined by radioimmunoassay. A 1% NH4OH solution caused gastric mucosal lesions with hemorrhagic necrosis and submucosal edema. PGE2 synthesis was not affected by NH4OH but was significantly increased by rebamipide. Rebamipide decreased the severity of NH4OH-induced gastric mucosal lesions in a dose-dependent manner. Pretreatment with indomethacin (5 mg/kg, subcutaneously) did not affect the protective effect of rebamipide; however, pretreatment with N(omega)-nitro-L-arginine (L-NNA, 1-10 mg/kg, intravenously), an inhibitor of nitric oxide synthase, attenuated the protective effect of rebamipide in a dose-dependent manner. Simultaneous administration of L-arginine (100 mg/kg) and L-NNA completely restored the protective effect of rebamipide, whereas D-arginine was inactive. These results suggest that nitric oxide contributes significantly to the protective effect of rebamipide against ammonia-induced gastric mucosal lesions.

[Analysis of Mycobacterium tuberculosis-derived substance which induces interleukin-12 production from macrophages]

Protection of hosts against tuberculosis depends on expression of cellular immunity. To express cellular immunity, interleukin 12 (IL-12) has been shown to play an important role. Although Mycobacterium tuberculosis is known to induce IL-12 from macrophages (M phi s), the mechanism for the induction is still unclear. To understand the mechanisms of IL-12 induction from M phi s by M. tuberculosis, the IL -12-inducing ability of substances derived from M. tuberculosis was investigated in vitro. Production of IL-12 in culture medium of M phi s was measured by ELISA system using specific antibodies. Live M. tuberculosis H37Rv induced slightly higher IL-12 production than live M. tuberculosis H37Ra upon stimulation of human or mouse alveolar macrophages (hAM phi s or mAM phi s). Heat-killed M. tuberculosis failed to induce IL-12 production of alveolar macrophages (AM phi). The responses of hAM phi s and mAM phi s to M. tuberculosis were remarkably different. mAM phi s produced five times larger amount of IL-12, compared with that from hAM phi s. Human peripheral blood mononuclear cells (PBMC) obtained by the density gradient centrifugation were also used for induction of IL-12 production. Although production levels of IL-12 from PBMC stimulated with M. tuberculosis were below the detectable level, addition of interferon-gamma (IFN-gamma) or neutralizing antibody against IL-10 augmented the production of IL-12 from PBMC, suggesting that IFN-gamma and IL-10 regulate the production of IL-12 from M phi positively and negatively, respectively. To characterize the physicochemical properties of IL-12-inducing molecules, M. tuberculosis H37Rv was disrupted by pressing with 1,000 bar and centrifuged and separated into cytosol and cell wall fraction. The culture filtrate was also examined on IL-12-inducing activity. Among the three subjects examined, cytosol was found to induce the highest production of IL-12 from mAM phi s 1 day after the stimulation. Addition of IFN-gamma to the cytosol fraction markedly increased the production of IL-12 from mAM phi s. The molecular weight of IL-12-inducing substance was shown to be more than 30kDa by fractionating with molecular filters. Treatment of 30kDa-fraction with IL-12-inducing activity by proteinase K completely abolished the activity. Furthermore, approximately 90% of IL-12-inducing activity of 30kDa-fraction was lost by proteinase K treatment even in the presence of IFN-gamma. These results indicate that the major component of IL-12-inducing activity is a protein. The identification of this IL-12-inducing active substance may provide a new therapeutic tool for tuberculosis.

Ultrastructural and permeability features of microvessels in the olfactory bulbs of SAM mice

The ultrastructural features of microvessels showing increased permeability to intravenously injected horseradish peroxidase (HRP) were examined in the olfactory bulbs of senescence-accelerated prone mice (SAMP8), which showed age-related deficits in learning and memory, and senescence-accelerated resistant mice (SAMR1), which did not show the age-related deficits. HRP was visualized with tetramethyl benzidine (TMB) and diaminobenzidine (DAB) for light and electron microscopic examination, respectively. In the olfactory bulbs of 13-month-old SAMP8 mice, the staining reaction with TMB for HRP appeared in the neuropil of central area (granule cell layer and subependymal layer), in the pia mater and in the vascular wall. Some vessels located in the central area showed several changes observed at the ultrastructural level. The cytoplasm of the endothelial cells, especially in the arterioles, was segmentally thickened and contained numerous vesicles and vacuoles, some of which were HRP positive. The endothelial cell surface was occasionally undulated with microvillous protrusions. Membranous inclusions within the basal lamina, suggesting the cellular (presumably pericytal) degeneration, were frequently observed, especially in venules. The collagen deposits were occasionally observed in the subendothelial space of some vessels. Perivascular cells with vacuolated inclusions or lipid-like droplets were present around some vessels in the central area of the olfactory bulbs of aged SAMP8 mice. On the other hand, in the microvessels located in the areas negative for HRP-TMB reaction, except the vessel walls, the cytoplasm of the endothelial cells with smooth luminal surface was flattened and some vesicles located there contained HRP-DAB reaction product. Weak staining reaction with TMB for HRP appeared also in the central area of the olfactory bulbs of 3-month-old SAMP8 mice and 3- and 13-month-old SAMR1 mice. The cytoplasm of the endothelial cells in the olfactory bulbs of these mice was focally thickened and contained some cytoplasmic vesicles. Occasionally, the endothelial cell surface was moderately undulated with few microvillous protrusions. Membranous inclusions within the basal lamina were not observed in these animals. These findings indicate that the endothelial cells and pericytes in some vessels located in the central area of the olfactory bulb of aged SAMP8 mice, which show staining reaction with TMB for HRP, are ultrastructurally changed, suggesting their altered functions.

[The mechanisms of gastrointestinal mucosal injury and repair]

Peptic ulcer disease are usually accompanied by diffuse inflammation over the gastroduodenal mucosa in addition to severe local inflammation at the site of ulceration. It is well known that inflammatory cytokine are the main mediators of inflammation. Cytokines may also play a part in acute gastroduodenal mucosal lesions (AGML) caused by NSAID, H. pylori, and stress. Among cytokines most involved in AGML, tumor necrosis factor-alpha (TNF-alpha), interleukin (IL) 1, IL-6, and IL-8 modulate chemotaxis, chemokinetics, and aggregation and release of lysosomal enzymes from neutrophils. Ulcer healing requires interaction of various cellular and connective tissue components. The stimulus for increased cell proliferation is most likely initiated by EGF and/or TGF-alpha which are mitogenic peptides for gastric epithelial cell at the initial stage in ulcer healing after ulcer induction. Transforming growth factor-beta (TGF-beta) also potentially involved in the ulcer healing process. During the chronic stage of ulceration, the growth of granulation tissue and generation of new microvessels by angiogenesis is stimulated by the fibroblast growth factors, platelet derived growth factor, TGF-beta, prostaglandins and/or IL-1 and TNF-alpha. The quality of mucosal restoration may be the most important factor in determining whether ulcers will recur. The proper restoration of the mucosal architecture requires balanced stimulation and interaction of both epithelial and connective tissue components, as well as, activation of growth factors which controls these components.

Hybrid-type stabilizer for off-pump direct coronary artery bypass grafting

We have developed a mechanical stabilizer for use in off-pump direct coronary artery bypass grafting. We consider it an improvement on the sucker-type stabilizer, although it uses the mechanisms of the compressor-type. Our hybrid stabilizer effectively immobilizes the local heart surface with light compression and low evacuation. We believe that its use will eliminate the need for further immobilization and thus reduce cardiac invasiveness.

Ulcer recurrence: cytokines and inflammatory response-dependent process

H. pylori and nonsteroidal antiinflammatory drugs (NSAIDs) are important factors in the recurrence of peptic ulcer diseases. However, H. pylori-negative recurring ulcers can also be found in nonusers of NSAIDs. The aim of this paper is to review recent data pertaining to mechanisms of ulcer recurrence. Prostaglandin E2 generation is impaired in the tissues of the ulcer scar site and prostaglandin depletion induced by administration of indomethacin during the healing of experimental gastric ulcer predisposes to future ulcer recurrence. Therefore, the prostaglandin deficiency may impair the quality of ulcer healing and thus increase the likelihood of future ulcer recurrence. Persistent infiltration of polymorphonuclear cells is the most prominent finding in the gastric ulcer scar in rats treated with indomethacin. Concomitant administration of prostaglandin E1-analog with indomethacin attenuates inflammatory infiltration and reduces future ulcer recurrence. Therefore, the inflammatory responses at the ulcer scar site may be a key to the quality of ulcer healing. Recent clinical findings suggest a close relationship between the quality of ulcer healing, infiltration of neutrophils and mononuclear cells, and future ulcer recurrence. Gastroprotective drugs such as prostaglandin analogs and prostaglandin inducers improve the quality of ulcer healing and reduce future recurrence. Production of inflammatory cytokines is stimulated by ulcerogenic factors such as NSAIDs, stress, and H. pylori infection. Inflammatory cytokines such as interleukin-1beta and tumor necrosis factor-alpha cause recurrence of healed ulcer. Synthetic prostaglandin E2 inhibits recurrence as well as the production of the cytokines.

Effect of rebamipide on Helicobacter pylori infection in patients with peptic ulcer

This study was designed to assess whether the gastroprotective drug, rebamipide, aids in eradication of H. pylori. One hundred twenty patients, endoscopically diagnosed with gastric or duodenal ulcers and H. pylori infection, were randomly allocated to two treatment groups. Sixty patients received 40 mg of omeprazole twice a day, 1500 mg of amoxicillin three times a day, and 300 mg of rebamipide three times a day (group OAR); the other 60 patients received the same dosage of omeprazole and amoxicillin but no rebamipide for two weeks (group OA). All patients subsequently received an H2-receptor antagonist for six weeks. At the end of the treatment, endoscopy was performed to assess the status of the ulcers as well as the extent of H. pylori infection. In the intent-to-treat (73.3 vs 51.7%, P = 0.014) and per-protocol analyses (75.9 vs 55.3%, P = 0.021) the cure rates for H. pylori infection in group OAR were found to be significantly higher than those in group OA. Our findings suggest that rebamipide aids in curing H. pylori infection. This drug does not induce formation of resistant colonies and has few side effects.

[Gastrointestinal lesions in liver cirrhosis]

The gastrointestinal bleeding commonly observed in patients with liver cirrhosis is usually from esophageal and gastric varices, gastroduodenal ulcer, and congestive gastropathy. Portal hypertension is the major causative factor of pathogenesis of GI lesions. In the present review, we focus in gastric mucosal defense and Helicobacter pylori infection in liver cirrhosis. Gastric mucosal defense is reduced in liver cirrhosis, especially prostaglandins which play a role in the gastric mucosal defense decreased in the gastric mucosal of patients with liver cirrhosis and rat portal hypertension model. Although H. pylori is strongly associated with peptic ulcer disease and chronic gastritis, several studies showed no relationship between H. pylori infection and gastroduodenal ulcer or the infection and congestive gastropathy in liver cirrhosis. Reduced gastric mucosal defense may account for the pathogenesis of GI lesions in liver cirrhosis.

Rebamipide prevents recurrence of gastric ulcers without affecting Helicobacter pylori status

Rebamipide, a gastroprotective drug developed in Japan, accelerates ulcer healing and reduces recurrence of experimental gastric ulcers. We examined the effects of rebamipide, given during healing of human gastric ulcers infected with Helicobacter pylori, on the quality of ulcer healing and ulcer recurrence. Sixty H. pylori-positive patients with gastric ulcers were randomly allocated to three treatment groups: group O (N = 20) received 20 mg of omeprazole every day for eight weeks, group OR (N = 20) received the same dose of omeprazole and 300 mg of rebamipide three times a day for eight weeks, and group OA (N = 20) received the same dose of omeprazole for eight weeks and 1500 mg of amoxicillin three times a day for the first two weeks. After this treatment was completed no other medication was given. Endoscopic examinations were performed at the end of therapy (for healing rate), one month later (for rate of H. pylori eradication) and every three months for follow-up (for ulcer recurrence rate). At the end of therapy, biopsy specimens were taken from the gastric ulcer scar and examined under the microscope for neutrophil and mononuclear cell infiltration. The ulcer healing rate of the three groups was almost the same; H. pylori in group OA was 65% and that of the other two groups was 0%. The number of patients with a flat ulcer scar pattern (good quality of ulcer healing) was increased and the neutrophil infiltration was significantly improved in groups OR and OA compared to group O. The ulcer recurrence rate was significantly lower in group OA and group OR than in group O. In conclusion, rebamipide is almost equipotent to amoxicillin plus omeprazole for the reduction of ulcer recurrence. The decreased recurrence rate by rebamipide may be due to improvement of the quality of ulcer healing, reflected as in the suppression of inflammatory cell infiltration in the scar, which results from either cure of H. pylori infection and/or treatment with a gastroprotective drug such as rebamipide.

Increased mRNA levels of transforming growth factor-beta1 and monocyte chemoattractant protein-1 in ulcer relapse caused by interleukin-1beta in rats

This study investigated the mRNA expression of transforming growth factor-beta1 (TGF-beta1) and monocyte chemoattractant protein-1 (MCP-1) in rat gastric tissues in which ulcers had relapsed due to interleukin-1beta (IL-1beta) administration. Rats with healed ulcers were administered IL-1beta (1 microg/kg) and killed after 0, 12, 24, or 48 hr. Both TGF-beta1 and MCP-1 mRNA levels were increased in the scarred gastric tissues at 24 hr (fourfold), when ulcers had not relapsed. Furthermore, the expression of these genes also increased in the ulcerated gastric tissues at 48 hr (fivefold), when 90% of healed ulcers had relapsed. On the other hand, the number of macrophages that had infiltrated the scarred gastric tissues at 24 hr was two times higher than that at 0 hr. At 48 hr, the number of macrophages that had infiltrated gastric tissues in which ulcers had relapsed was similar to that at 24 hr. Thus, TGF-beta1 and MCP-1 may be implicated in the macrophage infiltration, thereby leading to ulcer relapse due to IL-1beta.

Nine patients with hepatocellular carcinoma surviving for more than six years after treatment, including two patients who have survived without recurrence after hepatic lobectomy

Of patients treated for hepatocellular carcinoma (HCC) accompanied by liver cirrhosis at our University Hospital between 1985 and 1990, clinical background factors in nine patients (7.0% of all patients) who survived for more than six years were examined to clarify the conditions that facilitate long-term survival. In particular, we describe two cases among these patients who have survived without the recurrence of a liver tumor for more than six years after hepatic lobectomy. In eight of nine patients, surgery was performed as the initial treatment. In seven patients, HCC was solitary and there was no portal invasion. Six patients were evaluated as Stage I according to clinical staging. Furthermore, the two patients without recurrence after treatment have been taking immunostimulators since their initial treatment until the present. The above observations suggest that surgical treatment should be considered in patients in whom hepatic reserve capacity is well maintained despite a tumor size greater than 2 cm. Subsequent recurrence should be detected earlier, and percutaneous ethanol injection therapy (PEIT) with a focus on maintaining liver function should be repeated. In addition, multi-disciplinary treatment including medication with immunostimulators is beneficial.

Retroperitoneal Castleman's disease of the hyaline vascular type presenting arborizing calcification

Castleman's disease (CD) usually manifests as a solitary mediastinal tumor and only rarely as an isolated retroperitoneal mass. In the latter instances it is difficult to distinguish radiographically from other retroperitoneal masses. We report a 22-year-old female patient with retroperitoneal CD of the hyaline vascular type presenting with arborizing calcification. This characteristic calcification pattern is considered unique to CD, and is useful in diagnosis when present.

A novel human tumor necrosis factor alfa mutein, F4614, inhibits in vitro and in vivo growth of murine and human hepatoma: implication for immunotherapy of human hepatocellular carcinoma

Although treatment for hepatocellular carcinoma (HCC) has recently improved, most patients still relapse and die from this disease. The development of new therapeutic and preventive strategies for HCC is, therefore, required. A novel mutant protein (mutein) of human tumor necrosis factor alfa (TNF-alpha mutein F4614, 1SSSRGDSD... 29V ... 155L) was developed to decrease several adverse effects of TNF-alpha. F4614 is known to lack hypotensive effects of human TNF-alpha without losing its anti-tumor effect in mice transplanted with Meth-A sarcoma. Our study investigated the anti-tumor effects of F4614 against hepatoma cells in vitro and in vivo. F4614 significantly inhibited growth of all four tumor cells in vitro. A murine hepatoma cell line, MH134, when incubated in the presence of F4614, exhibited upregulation of surface major histocompatibility complex (MHC) class-I, intercellular adhesion molecule-1 (ICAM-1) and B7-1 molecules, and a decreased proportion of cells in the G2/M phase of the cell cycle. In addition, F4614 induced apoptosis in a significant number of MH134 cells. TNF-alpha and F4614 (5 microg/mouse daily for 5 days) showed similar anti-tumor activities in syngeneic MH134-bearing mice and heterogeneic PLC/PRF/5-bearing athymic nude mice. Intratumoral injection of F4614 or TNF-alpha was more effective than intravenous injection. Immunohistochemical analysis of the tumors treated by F4614 revealed that tumors were surrounded with a large number of Mac-1+ cells and a small number of CD4+ and CD8+ T cells; that suggests that intratumoral injection of F4614 elicited host immunoreactions. Thus, F4614 may be a new strategy for immunotherapy of HCC.

Cytotoxic enhancement of low dose-rate irradiation in human lung cancer cells by mild hyperthermia

PURPOSE

The aim of this study was to investigate the cell killing induced by low dose-rate irradiation (LDRI) simultaneously combined with long duration mild hyperthermia in LK87 human lung cancer cells. Cell cycle alteration due to this combined treatment was also observed.

MATERIALS AND METHODS

Human lung adenocarcinoma cells, LK87, were treated with concurrent LDRI (50 cGy/hr) and mild hyperthermia (38 to 42 degrees C). Cell survival was estimated by clonogenic assay. Flow cytometry was performed with FACScan. The treatments were simultaneously performed for up to 48 hr (24 Gy).

RESULTS

Survival curves of mild hyperthermia alone revealed development of chronic thermotolerance up to 48 hr, whereas LDRI plus hyperthermia caused an exponential decrease in survival. The LDRI cytotoxicities were enhanced by mild hyperthermia over a non-lethal temperature range. The Do values calculated from dose response curves at 37, 38, 39, 40, 41 41.5 and 42 degrees C were 6.55, 5.25, 4.24, 3.99, 3.46, 1.83 and 0.70 Gy, respectively. Cell cycle analysis demonstrated a remarkable G2 and a mild G1 block for LDRI alone, but only a G1 block was observed for LDRI combined with 41 degrees C hyperthermia.

CONCLUSION

The LDRI cytotoxicity was enhanced by long duration mild temperature hyperthermia. The suppression of chronic thermotolerance was considered to be a mechanism involved in this sensitization.

A novel class of mosquitocidal delta-endotoxin, Cry19B, encoded by a Bacillus thuringiensis serovar higo gene

Partially digested HincII fragments of DNA from a mosquitocidal strain of Bacillus thuringiensis serovar higo were cloned into pBluescript II SK(+) and propagated in Escherichia coli. Recombinant cells were screened immunologically for the production of parasporal inclusion antigens. One E. coli clone harboring a recombinant plasmid exhibited larvicidal activity to Culex pipiens molestus, but not to Anopheles stephensi. Hybridization experiments revealed that the gene of the toxin protein is located on a 110 kb plasmid of B. thuringiensis serovar higo. Sequence analysis detected an open reading frame of 2046 nucleotides encoding a polypeptide of 682 amino acid residues with a predicted molecular weight of 78,467. The gene encoded five block regions commonly conserved in the insecticidal protein genes of B. thuringiensis. Amino acid sequence of the 78 kDa protein shared 49% identity and 56% similarity with that of the Cry19A protein from B. thuringiensis serovar jegathesan. A new class of delta-endotoxin protein, designated Cry19B, was established on the basis of this protein.

Age-related changes in blood pressure in the senescence-accelerated mouse (SAM): aged SAMP1 mice manifest hypertensive vascular disease

Age-related changes in systolic blood pressure were assessed, using the senescence-accelerated mouse (SAM) model for aging research with strains SAMR1, SAMP1, and SAMP8. Each of the strains manifested a characteristic change in blood pressure with age. The SAMR1 strain, with normal aging, did not have chronologic changes from 2 to 27 months of age. The SAMP1 strain, with accelerated senescence, had a significant increase in blood pressure with age, and some (8 of 39) mice manifested hypertensive vascular disease characterized by high blood pressure, cardiac hypertrophy, and arteriolar fibrinoid necrosis at 11 to 14 months of age. The gradual increase in blood pressure after 8 to 10 months was considered to be preceded by progressive renal changes, from glomerulonephritis to contraction of the kidney, suggesting that the high blood pressure in the SAMP1 strain was of renal origin. Blood pressure in the SAMP8 strain, with age-related deficits in learning and memory, gradually decreased after 5 to 7 months of age, and was suggested to be due to the astrogliotic changes in response to spongiform degeneration in the medulla oblongata at 11 to 14 and 15 to 18 months of age.

Autoimmune hepatitis types IIa and IV in young men

Two young men with autoimmune hepatitis types IIa and IV are reported here. These rare types of the disease could be diagnosed by using the diagnostic criteria for scoring of autoimmune hepatitis established by the International Group.

Identification of the critical portions of the human IL-4 receptor alpha chain for activation of STAT6

Interleukin-4 (IL-4) has been shown to activate Janus kinase (Jak)-1 and Jak-3, followed by activation of STAT (signal transducers and activators of transcription) 6. This Jak-STAT pathway is central to the initiation of IL-4 activities. In this study, we identified the essential region for the proliferation signal and activation of Jak-1, Jak-3, and STAT6 in the cytoplasmic domain of the human IL-4 receptor alpha chain (hIL-4R alpha) using a mouse T cell line CTLL-2. We found that the region between amino acid 353 and 393 is critical for the proliferation signal and activation of STAT6, but not for tyrosine phosphorylation of Jaks. These results suggest that in addition to the "Box-1" portion, which is known to be essential for Jak-1 activation, the more membrane-distal region of hIL-4R alpha is also necessary for activation of STAT6.

Characterization of mosquito larvicidal parasporal inclusions of a Bacillus thuringiensis serovar higo strain

The parasporal inclusion proteins of the type strain of Bacillus thuringiensis serovar higo (H44), that have moderate mosquitocidal activity, were characterized. The purified parasporal inclusions, spherical in shape, were examined for activity against the two mosquito species, Culex pipiens molestus and Anopheles stephensi and the moth-fly, Telmatoscopus albipunctatus. The LC50 values of the inclusion for the two mosquitoes were 3.41 and 0.15 microgram.ml-1, respectively. No mortality was shown for T. albipunctatus larvae by the inclusions at concentrations up to 1 mg ml-1. Solubilized parasporal inclusions exhibited no haemolytic activity against sheep erythrocytes. Parasporal inclusions consisted of eight proteins with molecular masses of 98, 91, 71, 63, 59, 50, 44 and 27 kDa. Of these, the 50 and 44 kDa proteins were the major components. Analysis with immunoblotting revealed that, among several inclusion proteins of B. thuringiensis serovar israelensis, only two proteins of 130 kDa and 110 kDa reacted weakly with antibodies against higo proteins. N-terminal amino acid sequences of the 98, 91, and 71 kDa proteins showed 85-100% identity to those of the two established Cry protein classes, Cry4A and Cry10A.

Progression to moderate or severe mitral regurgitation after percutaneous transvenous mitral commissurotomy using stepwise inflation technique

Progression to moderate or severe mitral regurgitation (MR) was studied after Inoue balloon percutaneous transvenous mitral commissurotomy (PTMC) using the stepwise inflation technique, performed at increments of 1 mm of balloon diameter, in 49 consecutive patients with rheumatic mitral stenosis (aged from 32-73 years; 8 males, 41 females). The patients were classified on the basis of the degree of MR after PTMC, compared with that before PTMC, into either Group A, development of moderate or more severe (> or = grade 2) MR (n = 8) or Group B, no increase in MR or development of mild (grade 1) MR (n = 41). Progression to moderate or severe MR was significantly associated only with advanced age (60 +/- 8 vs 52 +/- 10 years, p < 0.05) and narrower mitral valve area (0.87 +/- 0.35 vs 1.11 +/- 0.29 cm2, p < 0.05), but other characteristics before PTMC were similar in both groups. There was no difference between the two groups in the total number and degree of balloon inflation. Immediately before the final inflation, the left atrial mean pressure and v wave pressure were decreased in smaller degrees in Group A compared with Group B (-2 +/- 2 vs -5 +/- 4 mmHg, p < 0.05; -2 +/- 2 vs -6 +/- 6 mmHg, p < 0.05, respectively). Thus, the stepwise inflations require careful monitoring of changes in the left atrial pressure and waveform to recognize the aggravation of MR, especially in older patients with severe stenosis. Patients who do not have a significant drop in left atrial mean pressure and v wave pressure during stepwise inflations of the balloon might be at risk of development of moderate or severe MR after further dilations.

The offset cortical potential: an electrical correlate of movement inhibition in man

Nine normal subjects were asked to make either a brisk isometric pinch of a force transducer held between the forefinger and thumb, or to hold a pinch for approximately 15 s and then release the force suddenly without any overt antagonist contraction. EEG activity was averaged about the onset or offset of EMG activity, and movements were made in the subjects' own time. All subjects found the task simple. The EEG activity preceding offset of contraction (offset cortical potential) was significantly smaller in lateral leads than that seen before onset of contraction. Midline activation was similar in both tasks. We suggest that in the onset task, motor cortex activity related to the act to be performed contributes substantially to the EEG potentials in lateral leads. This activity is absent in the offset task which requires only withdrawal of tonic input to motor cortex. Midline activity, common to both onset and offset tasks, could reflect timing, attentional, or other processes. The results are discussed in relation to previous data from an isotonic relaxation task.