Plasma neuropeptide Y concentrations in patients on hemodialysis

BACKGROUND

Neuropeptide Y (NPY) is a 36-amino-acid peptide that was originally isolated from the porcine brain. NPY, in contrast to leptin, is one of the most potent appetite stimulants. In some previous studies, NPY was found to be correlated with mean blood pressure (MBP) and fluid volume in patients on hemodialysis (HD), contributing to volume-induced hypertension. However, it is still unclear which NPY-sensitive neuronal pathways are responsible for the various changes seen in response to central NPY administration. In this study we analyzed the correlation of circulating levels of NPY with parameters of nutritional conditions, and we investigated the relationships between NPY concentrations and clinical markers of fluid volume in patients on HD. We also evaluated the effects of high-flux dialysis membranes on plasma NPY levels as compared with those of low-flux membrane.

METHODS

Plasma NPY concentrations in patients on regular HD were measured using commercially available radioimmunoassay (RIA) kits. We examined the relationship between plasma NPY concentration and other clinical indices in patients on HD.

RESULTS

Plasma NPY concentrations were inversely correlated with the serum urea nitrogen levels (r = -0.32) as well as protein catabolic rate (PCR) (r = -0.28). Plasma NPY was also correlated with the increase in body weight between HD sessions (r = 0.29). On the other hand, plasma NPY concentrations were not correlated with MBP, atrial natriuretic peptide (ANP), or adrenomedullin (AM). The reduction rate of plasma NPY with a high-flux dialysis membrane was significantly higher than that with a low-flux dialysis membrane.

CONCLUSIONS

The secretion of NPY may be enhanced in a poor state of nourishment and stress induced by fluid volume overload in patients on HD, and plasma NPY is removed by a high-flux dialyzer.

Antibodies to GAD in Japanese patients classified as Type 2 diabetes at diagnosis. High titre of GAD Ab is a predictive marker for early insulin treatment--report of west Japan (Kyushu, Yamaguchi, Osaka) study for GAD Ab(+) diabetes

AIM

We evaluated the prevalence of GAD Ab in Japanese Type 2 diabetic patients treated with oral hypoglycaemic agents (OHA) and/or diet and followed GAD Ab(+) patients to assess the usefulness of GAD Ab as a marker for future insulin treatment prospectively.

METHODS

A total of 2658 Japanese Type 2 diabetic patients treated by OHA and/or diet were randomly selected between April 1996 and December 1998. The clinical characteristics at entry were assessed and patients were followed for 1-3 years.

RESULTS

The overall prevalence of GAD Ab among Type 2 diabetic patients was 2.0%. Forty-five had a history of diabetes of < or = 5 years (short history) while those with duration > 5 years (long history) totalled nine. Among them, 47% of patients with a short history did not require insulin in the follow-up period. However, none of those with a long history required insulin treatment within 2 years. Comparison of patients based on GAD titre in those with short history showed that 33% of patients in the high-titre group (> or = 20 U) required no insulin treatment in the first year of follow-up. In contrast, this proportion was 80% in the first and 67% in the second year in the low-titre group (< 20 U).

CONCLUSIONS

The prevalence of GAD Ab in Japanese patients with a short and long history of diabetes was 2.8% and 0.9%, respectively. The presence of GAD Ab in Japanese Type 2 diabetic patients with a short history of diabetes is a marker for early insulin treatment.

A phylogenetic hypothesis for the distribution of two genotypes of the pig tapeworm Taenia solium worldwide

Genetic polymorphism was determined among 13 isolates of Taenia solium from various regions using PCR-amplified sequences of 2 mitochondrial genes: cytochrome c oxidase subunit 1 and cytochrome b. The 2 phylogenies obtained were similar to each other regardless of the genes examined. The isolates from Asia (China, Thailand, Irian Jaya and India) formed a single cluster, whereas the isolates from Latin America (Mexico, Peru, Ecuador, Bolivia and Brazil) combined with those from Africa (Tanzania, Mozambique and Cameroon) to form an additional cluster. These results and historical data of swine domestication, distribution of pigs and colonization suggest that T. solium was introduced recently into Latin America and Africa from different regions of Europe during the colonial age, which started 500 years ago, and that the tapeworm of another origin independently spread in Asian countries.

Analysis of glucose tolerance in twin gestations using an oral glucose load

The effect of twin gestation on carbohydrate metabolism was evaluated using a 75 g oral glucose tolerance test (75 g OGTT). A 75 g OGTT was performed in 63 twin gestations and 3 791 singleton gestations during the third trimester. Plasma glucose concentrations were measured in the pregnant women under fasting conditions as well as 30 min, 1 h, and 2 h after ingestion of glucose (75 g oral load), and serum insulin concentrations were measured in fasting and 30 min post-ingestion samples. Women with twin gestations showed significantly lower plasma glucose concentrations during fasting and 30 min after the glucose load in the samples taken than those with singleton gestations. No significant difference in serum glucose concentrations was found in the other specimens. There were no cases of gestational diabetes mellitus in our study. Although women with twin gestations demonstrated lower plasma glucose concentrations than women with singleton gestations, the difference observed was subtle. We could not find any significant differences in these plasma glucose values as used to define a pathologic OGTT between twin and singleton pregnancies, with the exception of the fasting value.

NBT-II carcinoma behaviour is not dependent on cell-cell communication through gap junctions

To study the mechanism(s) underlying the proliferation of heterogeneous cell populations within a solid tumour, the NBT-II rat bladder carcinoma system was used. It has been first investigated whether the different cell populations are coupled through gap junctions (GJIC). Cells overexpressing the Cx43 were generated to test for any tumour suppressive activity in vivo. To determine whether GJIC is essential for tumour proliferation and the establishment of a cooperative community effect, NBT-II cells that are incompetent for cell coupling were generated. The data report that (i) carcinoma cells expressing or not FGF-1 are coupled through GJIC in vitro and in coculture and express the gap junction protein Cx43, (ii) overexpression of Cx43 in these cells does not affect their in vitro coupling capacities and in vivo tumourigenic growth properties, (iii) inhibition of GJIC through antisense strategy has no in vivo obvious consequence on the tumour growth properties of the carcinoma, and (iv) the community effect between two carcinoma cell populations does not critically involve cell coupling through gap junctions.

Separation of highly fluorescent proteins by SDS-PAGE in Acroporidae corals

This study characterized the spectral properties of Acropora tenuis, A. nasuta, A. secale, and A. aspera, all of which showed strong colorful fluorescence under ultraviolet light-A (black light). The emission maxima of fluorescence from the intact corals were 517, 482, 484, and 514 nm in A. tenuis, A. nasuta, A. secale, and A. aspera, respectively. Using a soluble fraction of cell-free extract of the corals, we applied a method of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) to separate each fluorescent protein component contained in the corals. Green fluorescent bands were detected in all Acropora examined, although their apparent molecular mass and relative content were different. A. aspera had two orange bands in addition to the green one. The major excitation and emission peaks of the orange fluorescence bands were almost identical (476 and 478 nm), however, they were discernible by their spectral profiles and molecular masses. Some biochemical properties of the highly fluorescent proteins of Acropora are described and implications of the results are discussed.

Association between IA-2 autoantibody epitope specificities and age of onset in Japanese patients with autoimmune diabetes

The IA-2 is a major autoantigen of type 1 diabetes belonging to the protein tyrosine phosphatase family. We report on the humoral autoimmunity to an alternatively-spliced variant of IA-2 (IA-2 variant) and autoimmune-mediated diabetes age of onset association with IA-2 autoantibody epitope specificities, in 144 recent-onset patients with type 1 diabetes and 54 GAD autoantibody-positive patients with type 2 diabetes. The cytoplasmic domain of IA-2 (IA-2ic) detected a somewhat greater proportion of patients expressing autoantibodies than IA-2 variant (56%vs. 52% of patients with type 1 diabetes and 17%vs. 9% of GAD autoantibody-positive patients with type 2 diabetes). Conversely, only 1% of IA-2 variant autoantibody-positive patients failed to react to IA-2ic construct. Among 80 patients with type 1 diabetes who were positive for autoantibodies to IA-2ic, 8% recognized the juxtamembrane region (JM, representing amino acids 601-629) only, 64% bound the protein tyrosine phosphatase (PTP)-like domain of IA-2 only, and 29% bound both JM and PTP epitopes. Autoantibodies to the PTP-like domain were prevalent in children and adolescents with type 1 diabetes. The age of disease onset in patients with IA-2JM autoantibodies only, was significantly higher than those in patients reacted with the PTP-like domain of IA-2 (P< 0.02). Among GAD autoantibody-positive patients with type 2 diabetes reacted with IA-2ic, 44% bound the JM region only, and 33% bound epitopes in the PTP-like domain only; 22% had autoantibodies to both regions. The frequency of GAD autoantibody-positive patients with type 2 diabetes positive for autoantibodies to the JM region only, was significantly higher than that in patients with type 1 diabetes (P< 0.01). IA-2PTP autoantibodies were significantly associated with HLA-DR4, while the additional reactivity to IA-2JM was associated with HLA-DR9 allele. These results suggest that autoantibody recognition of IA-2 epitopes in autoimmune diabetes is associated with age of disease onset, which may reflect the intensity of the beta-cell destruction process.

Gap junctions and fluid flow response in MC3T3-E1 cells

In the current study, we examined the role of gap junctions in oscillatory fluid flow-induced changes in intracellular Ca(2+) concentration and prostaglandin release in osteoblastic cells. This work was completed in MC3T3-E1 cells with intact gap junctional communication as well as in MC3T3-E1 cells rendered communication deficient through expression of a dominant-negative connexin. Our results demonstrate that MC3T3-E1 cells with intact gap junctions respond to oscillatory fluid flow with significant increases in prostaglandin E(2) (PGE(2)) release, whereas cells with diminished gap junctional communication do not. Furthermore, we found that cytosolic Ca(2+) (Ca) response was unaltered by the disruption in gap junctional communication and was not significantly different among the cell lines. Thus our results suggest that gap junctions contribute to the PGE(2) but not to the Ca response to oscillatory fluid flow. These findings implicate gap junctional intercellular communication (GJIC) in bone cell ensemble responsiveness to oscillatory fluid flow and suggest that gap junctions and GJIC play a pivotal role in mechanotransduction mechanisms in bone.

Relationship between age-related increases in rat liver lipid peroxidation and bile canalicular plasma membrane fluidity

Aging is associated with increased cellular levels of lipid peroxides and reactive oxygen species. This increase in the radical species may affect membrane fluidity and consequently membrane functions. We attempted to determine whether age-related increases in lipid peroxide and reactive oxygen species levels affect the annular fluidity of the bile canalicular plasma membrane in young (2-3 weeks old), adult (20 weeks old) and old (100 weeks old) rats. Hepatic levels of lipid peroxides measured with thiobarbituric acid reactive substances (TBARS), reactive oxygen species and reduced glutathione were significantly higher in the old rats than in the young and adult rats. Arachidonic acid (AA) levels increased and docosahexaenoic acid (DHA) levels decreased in the isolated canalicular plasma membrane of the old rats, and the ratio of DHA to AA thus decreased significantly with rat aging. Hepatic TBARS levels correlated negatively with molar ratios of DHA to AA. The annular fluidity of the bile canalicular plasma membrane decreased significantly in the old rats compared with that in the young and adult rats. These results suggest that the age-related decrease in DHA content of the bile canalicular plasma membrane and the molar ratio of DHA to AA may be associated with age-related deterioration of membrane annular fluidity.

Control of intracellular movement of connexins by E-cadherin in murine skin papilloma cells

The gap junctional intercellular communication-deficient mouse skin papilloma cell line P3/22 expresses Cx43 but not E-cadherin. The E-cadherin gene-transfected cells (P3E1) communicate in a calcium-dependent manner and they were used to study how E-cadherin restores the function of connexins. At low calcium, Cx43 molecules remain in the cytoplasm of P3E1 cells and appear at cell-cell contact areas only in high-calcium medium. While Cx43 is unphosphorylated in P3E1 cells in low-calcium medium, two phosphorylated bands appeared at high calcium. However, when Cx26, which has no C-terminal tail that can undergo phosphorylation, was expressed in P3E1 cells, this connexin also moved to the plasma membrane after the calcium shift and partly colocalized with Cx43, suggesting that C-terminal phosphorylation is not essential for E-cadherin-mediated intracellular transport of connexins. In low calcium, both Cx26 and Cx43 remained and colocalized in the endoplasmic reticulum. As early as 30 min after the shift to high-calcium medium, both Cx43 and Cx26 began to accumulate in the Golgi apparatus. Intracellular movement of connexins to the cytoplasmic membrane at high calcium was effectively blocked by cytochalasin D and brefeldin A. These results suggest that E-cadherin junction formation at high calcium leads to formation of actin cables, which directly or indirectly transport connexins from the cytoplasm to the cell-cell contact membranes via the Golgi apparatus.

Relationships of serum levels of insulinlike growth factors with indices of bone metabolism and nutritional conditions in hemodialysis patients

Insulinlike growth factor (IGF) I and IGF-II are synthesized in osteoblasts and stimulate proliferation, differentiation, and matrix synthesis in these cells. There is some evidence that IGFs act on bone cells not only by paracrine but also by endocrine pathways, suggesting that circulating IGFs may be of importance for the regulation of bone metabolism. On the other hand, the serum IGF-I level is also thought to be a good indicator of the nutritional conditions in hemodialysis patients. The present study was performed to analyze the correlations of circulating levels of IGF-I, IGF-II, IGF-binding protein (IGFBP) 1 and IGFBP-3 with biochemical markers of bone metabolism and parameters of the urea kinetic model which reflect nutritional conditions in hemodialysis patients. We also examined the differences between these relationships in male and female patients on hemodialysis. Sixty-two hemodialysis patients, 36 men (male group) and 26 women (female group), were included in this study. We measured the serum levels of IGF-I, IGF-II, IGFBP-1, and IGFBP-3. The bone mineral content (BMC) of the radius was measured by dual-energy X-ray absorptiometry. We calculated Kt/V, protein catabolic rate, and percent creatinine generation rate (%CGR). We also examined the relationships between serum levels of IGFs and BMC and the parameters of the urea kinetic model. It was found that the serum levels of IGF-I in the hemodialysis patients were almost the same as those in the control group. However, the serum levels of IGF-II, IGFBP-1, and IGFBP-3 in the hemodialysis patients were significantly higher than those in the control group. In the male group, the serum IGF-I levels showed a significant correlation with both serum intact parathyroid hormone levels and BMC, but no significant correlations between these indices were found in the female group. The serum levels of both IGF-I and IGF-II showed significant correlations with %CGR in the male group, but not in the female group. Stepwise multiple regression analysis was performed to clarify the relationship between serum levels of IGFs and BMC or %CGR. It was found that age, hemodialysis duration, serum intact parathyroid hormone levels, and sex were independent factors associated with BMC. The %CGR was associated independently with serum levels of IGF-I, and IGF-II and with the presence of diabetes mellitus. In conclusion, it is thought that serum levels of IGF-I and IGF-II can be used as indices of nutritional conditions in hemodialysis patients. However, the serum IGF-I level cannot be used as a marker of bone metabolism in hemodialysis patients.

Postural tachycardia syndrome in a 28-year-old Japanese woman

Postural tachycardia syndrome is defined as the development of orthostatic symptoms without orthostatic hypotension. We report a 28-year-old female patient with postural tachycardia syndrome who exhibited palpitation, low-grade fever and weight loss. Evaluation of autonomic nervous system functions showed that cardiovagal function was normal. Sweat response to acetylcholine was decreased. Excessive blood pressure elevation was seen in phase IV of the Valsalva maneuver. Pathophysiologic factors in this case were considered to be alpha adrenergic denervation and beta adrenergic hyperresponsiveness. It is important that this syndrome be widely recognized and properly diagnosed.

Reduction of malignant phenotype of HEPG2 cell is associated with the expression of connexin 26 but not connexin 32

Connexin (Cx) genes have a negative growth effect on tumour cells with certain specificity. However, it is not clear whether each Cx gene can act similarly in growth control. Hepatocytes normally express Cx26 and Cx32 as their major gap junction genes, but HepG2 cells, a hepatoma cell line, are deficient in gap junctional intercellular communication (GJIC) based on the down-regulation of Cx26 and aberrant localization of Cx32. In this study, we showed that some of the expressed Cx26 protein in HepG2 cells localized in the plasma membrane and contributed to recovery of GJIC, while the Cx32 protein remained localized in the cytoplasm. The Cx26-transfected clones showed a significantly slower growth in vivo as well as in vitro and reduced anchorage-independent growth ability compared with a mock-transfected clone. Cx26-transfected cells had more regular cell layers due to the re-establishment of the E-cadherin cell adhesion complex. E-cadherin expression following Cx26 transfection was induced. Cx26 expression simultaneously brought E-cadherin and beta-catenin proteins into the plasma membrane without any change in the expression level of beta-catenin protein. These results suggest that the expression of Cx26 contributes to negative growth control of HepG2 cells and the morphological change through the induction of E-cadherin and subsequent formation of cell adhesion complex.

A suspected case of proximal diabetic neuropathy predominantly presenting with scapulohumeral muscle weakness and deep aching pain

A 48-year-old man with a 14-year history of type 2 diabetes with proliferative diabetic retinopathy and distal symmetrical diabetic polyneuropathy visited our hospital. Eight months later, he subacutely developed difficulty in both shoulder movement and trouble standing up from a squatting position. This was accompanied by severe bilateral shoulder and thigh pain. Magnetic resonance imaging of the brain, cervical and lumbar spine, computed tomography of the shoulder and X-ray films of the cervical spine and shoulder revealed no abnormality. Cerebrospinal fluid showed a mild elevation of protein (0.93 g/l) without cell infiltration. Antiganglioside antibodies and point mutation of mitochondrial DNA at position 3243 were not found. Neuropathology of the sural nerve showed a moderate myelinated fiber loss, active axonal degeneration, but onion-bulb formation, endoneurial or epineurial vasculitis were not observed. Electromyography revealed neurogenic changes in the proximal upper limb muscles. Nerve conduction studies revealed mild bilateral slowing in nerve conduction velocity in both of the upper and lower limbs. The diagnosis of this patients was suspected to be a proximal diabetic neuropathy (diabetic amyotrophy). The pain and muscle weakness had persisted more severely in the shoulder than in the thigh throughout the clinical course. His unbearable symptoms could be partially alleviated by an administration of a selective serotonin reuptake inhibitor, fluvoxamine maleate. Proximal diabetic neuropathy is a rare disabling type of neuropathy, which is characterized with subacute bilateral muscle weakness and wasting in the proximal part of the lower limbs. The involvement of the scapulohumeral region observed in this case is very unusual in proximal diabetic neuropathy.

Relationship of androgens to muscle size and bone mineral density in women with polycystic ovary syndrome

OBJECTIVE

To investigate the relationship of androgens to regional muscle size and bone mineral density (BMD) in women with polycystic ovary syndrome (PCOS).

METHODS

Seventy-one amenorrheic and right-side dominant women with PCOS (mean age +/- standard deviation 28.1 +/- 6.7 years) were enrolled. Baseline characteristics included age, height, weight, and body mass index (BMI). Regional BMD and lean mass were measured by whole-body scanning with dual-energy x-ray absorptiometry. Serum levels of testosterone, dehydroepiandrosterone sulfate (DHEAS), and androstenedione were measured by radioimmunoassay. Correlations between regional BMD and variables were investigated using a Pearson correlation test and multiple regression analysis.

RESULTS

Serum testosterone levels correlated significantly with lean mass of the left arm, right arm, trunk, left leg, and right leg (r =.34, P <.05 to r =.50, P <.01). Regional lean mass correlated significantly with respective regional BMD (r =.30, P <.05 to r =.68, P <.001). These relationships remained significant after adjusting for age, height, and weight. Serum testosterone levels were not correlated with BMD of the bilateral arms and lumbar spine. Although serum testosterone levels correlated with leg BMD (r =.34, P <.05 to r =.45, P <.01), significance did not persist after adjusting for respective regional lean mass.

CONCLUSION

Testosterone influences regional BMD through increasing regional muscle mass in women with polycystic ovary syndrome.

CTLA4 gene polymorphism contributes to the mode of onset of diabetes with antiglutamic acid decarboxylase antibody in Japanese patients: genetic analysis of diabetic patients with antiglutamic acid decarboxylase antibody

AIM

The mode of onset is occasionally similar in Type 1 and Type 2 diabetes mellitus, and some patients with Type 2 diabetes are positive for antiglutamic acid decarboxylase antibody (GAD Ab). We investigated the contribution of Type 1 diabetes susceptibility genes to the progression of the insulin-deficient state and mode of onset of Type 2 diabetes in GAD Ab-positive (GAD-Ab+) patients. We examined the variable number of tandem repeats in the promoter region of the insulin gene (INS-VNTR, insulin-dependent diabetes mellitus (IDDM) 2) and cytotoxic T lymphocyte antigen 4 (CTLA4, IDDM12) as representative of Type 1 diabetes susceptibility genes.

METHODS

Patients with Type 2 diabetes who were GAD-Ab+ (n = 51) were selected for this study. In INS-VNTR, the class I allele was classified according to length (1S, 25-38 repeat units; 1M, 39-41 repeat units; 1L, 42-44 repeat units) and the exact class I allele length was analysed by specific polymerase chain reaction (PCR) amplifications. Analyses of classes II and III were performed by Southern blot. CTLA4 gene polymorphism (exon 1 position 49, G/A) was analysed by PCR-restriction fragment length polymorphism.

RESULTS

The distribution of INS-VNTR was no different between Type 1 diabetes and Type 2 diabetes with GAD Ab. The allele frequencies of CTLA4 gene polymorphism G and A in Type 2 diabetes/GAD-Ab+ were significantly different from those of Type 1 diabetes/GAD-Ab+ (G: 53%, A: 47% vs. G: 84%, A: 16%; P < 0.0001).

CONCLUSIONS

Our data showed that GAD-Ab+ Japanese patients presenting with Type 2 diabetes have shifted A allele while patients with abrupt onset have shifted G allele of CTLA4 gene polymorphism. Our results suggest that immunological function and polymorphism of the CTLA4 gene may contribute to the pathogenesis and progression of Type 1 diabetes.

Plasma adrenomedullin levels in patients on hemodialysis

Adrenomedullin (AM) is a hypotensive peptide that has recently been isolated from human pheochromocytoma. In this study, we measured plasma AM concentrations in 54 patients on hemodialysis (HD) and examined the clinical significance. We also evaluated the effects of high-flux and low-flux dialysis membranes on plasma AM levels. The average value of plasma AM at pre-HD (4.44 +/- 0.16 fmol/ml) was significantly elevated compared with that in 44 healthy volunteers (1.31 +/- 1.41 fmol/ml) (p < 0.0001). The plasma AM concentrations at pre-HD showed a negative correlation with age and mean blood pressure (MBP) at pre-HD. The plasma AM concentrations at post-HD showed a negative correlation with MBP at post-HD and a negative correlation with the reduction rate of AM. Multiple regression analysis showed that age and MBP were independent factors associated with plasma AM at pre-HD and that MBP and reduction rate of AM were independent factors associated with plasma AM at post-HD. We investigated the differences between high-flux dialyzers (PS-UW, PS-N and FB-F) and a low-flux dialyzer (AM-BC-F), and we found that high-flux dialyzers removed plasma AM more efficiently than a low-flux dialyzer did. In addition, in 3 patients on HD, plasma AM levels decreased significantly during isovolumic dialysis using a high-flux dialyzer, despite the fact that there were no significant changes in MBP and ANP. In conclusion, elevation in plasma AM level causes a fall in MBP in patients on HD, therefore, removal of AM by HD treatment using a high-flux dialyzer contributes to the stability of blood pressure during HD.

Attention and visual interference stimulation affect somatosensory processing: a magnetoencephalographic study

In our previous study, continuous visual (cartoon and random dot motion) and auditory (music) stimulation changed the somatosensory evoked magnetic fields following electrical stimulation of the median nerve in human subjects. They enhanced the middle-latency components (3M and 4M) generated in the contralateral primary somatosensory cortex, and reduced the MI component generated in the ipsilateral secondary somatosensory cortex. We speculated that such interference effects were caused by activation of polymodal neurons in areas 5 and/or 7 of the parietal lobe as well as in the medial superior temporal region and superior temporal sulcus. However, we could not exclude the effect of attention on such interference effects. In the present study, to know the effect of attention on visual and auditory interference in these changes, we stimulated the bilateral median nerves unilaterally in a random order, and asked subjects to count the number of times the left median nerve was stimulated while visual or auditory interference was applied. Five components (1M-5M) were identified in the hemisphere contralateral to the stimulated nerve and only one component (MI) was found in the ipsilateral hemisphere. The 3M and 4M components (33-75 ms in latency) were enhanced by both attention and visual interference stimulation but not by auditory stimulation. The 5M component (70-115 ms) and MI component (70-133 ms) were enhanced by attention, but were not changed by attention together with visual or auditory interference. Summarizing the results of our previous study and the present study, (1) visual interference alone enhanced the 3M and 4M but reduced the MI, and (2) attention alone also enhanced the 3M and 4M, and enhanced the 5M and MI. As a result, (3) visual interference with attention enhanced the 3M and 4M more, and showed no significant change of the 5M and MI. This was compatible with a summation of the effects caused by visual interference alone and attention alone, but some interactions between visual interference and attention might have taken place. The locations of dipoles of all components were not significantly changed by attention or any interference stimulation. These findings support the idea that there are significant interactions of activities relating to somatosensory stimulation, visual stimulation and cognitive function, in both the primary and the secondary somatosensory cortex in humans.

Suppressed gap junctional intercellular communication in carcinogenesis of endometrium

To examine whether and at which stage of endometrial carcinogenesis decreased connexin expression occurs, we investigated changes in the expression of the gap junction proteins, connexin 26 (Cx26), Cx32 and Cx43, in human endometrial hyperplasia and cancer samples. Forty-eight endometrial tissue samples (15 endometrial hyperplasias and 33 endometrial cancers) were subjected to immunofluorescence and RT-PCR analysis. In endometrial hyperplasia, Cx26 was aberrantly expressed in all samples as revealed immunohistochemically. There was weak or negative expression in 12 samples (80.0%) and diffuse expression in cytoplasm in 3 samples (20.0%). Cx32 expression in those samples was similar to that of Cx26; there was weak or negative expression in 11 samples (73.3%) and diffuse expression in 4 samples (26.7%). In endometrial cancer, Cx26 was expressed weakly or negatively in 25 samples (75.8%), diffusely in 6 samples (18.2%) and normally in 2 samples (6.1%), while Cx32 was expressed weakly or negatively in 26 samples (78.8%), diffusely in 5 samples (15.2%) and normally in 2 samples (6.1%). It was confirmed that weak staining of Cx26 and Cx32 was due to poor expression of their mRNA. All samples showed weak Cx43 protein expression as revealed by immunohistochemical analysis. In the majority of samples, concomitant expression levels of Cx26 and Cx32 protein were observed, confirming our long-term hypothesis that Cx26 and Cx32 are both abnormally regulated in a coordinated fashion in the endometrium. Our results indicate that during endometrial carcinogenesis, loss of gap junctional intercellular communication (GJIC) may occur due to the suppressed expression and the aberrant localization of connexin at relatively early stages.

Hodgkin's disease preceded by unique neurological symptoms

This is the first case report of Hodgkin's disease (HD) which showed both remission and exacerbation of neurological signs before a confirmed diagnosis of HD. The episodes occurred three times and multiple lesions were involved. Immunoabsorption plasmapheresis and double filtration plasmapheresis were effective for the first episode, whereas, corticosteroids partly improved the second and third episodes. Fever and lymph node swelling were apparent afterward and she was diagnosed as having HD from a supraclavicular lymph node biopsy. The remaining neurologic deficits responded to chemotherapy and radiotherapy. The neurological symptoms were considered as a paraneoplastic syndrome of HD.

Determination of bisphenol a in effluents of hemodialyzers

This study was designed to determine whether bisphenol A (BPA) is eluted from hemodialyzers in which polycarbonate and polysulfone based on BPA are used as materials. Four types of polysulfone hemodialyzer (PS hemodialyzer: PS-A, PS-B, PS-C and PS-D) and an ethylene-vinyl alcohol copolymer dialyzer (EVAL hemodialyzer) were used in this study. In the PS-C, PS-D and EVAL hemodialyzers, polycarbonate was used in the case headers at both ends of the hemodialyzer. In in vitro experiments, the hemodialyzers were filled with reverse osmotic water, and BPA concentrations were measured. Saline solution (200 ml) was then circulated through a blood circuit tube connected to the hemodialyzer, and BPA concentrations in the saline solution were measured. In in vivo experiments, BPA concentrations in whole blood samples from hemodialysis patients treated with PS-C (n = 3) and PS-D (n = 3) hemodialyzers were measured. In in vitro experiments, BPA was detected in the effluents of the PS-C, PS-D and EVAL hemodialyzers. In in vivo experiments, BPA was detected in whole blood samples from hemodialysis patients treated with the PS-D hemodialyzer (mean value, 0.77 ppb). This is the first report of BPA elution from hemodialyzers in which polycarbonate and polysulfone are used, and also the first report of detection of BPA in whole blood samples from patients on hemodialysis.

Involvement of gap junctions in tumor suppression: analysis of genetically-manipulated mice

Accumulating evidence indicates that gap junctions play an important role in the maintenance of normal cell growth, so that genes for the connexin gap junction proteins form a family of tumor-suppressor genes. Although mice from which nine types of connexin gene are deleted have been established, little information from carcinogenesis experiments with these mice is available. We have previously found several mutant forms of connexin 32 (Cx32) to be able to inhibit, in a dominant-negative manner, gap junctional intercellular communication (GJIC) exerted by wild-type Cx32. By introducing a gene for such a dominant-negative Cx32 mutant expressed under the control of a liver-specific albumin gene promoter, we have generated transgenic mouse lines in which the function of Cx32 is down-regulated only in the liver. Although GJIC was diminished in the transgenic liver as expected, the reduced GJIC did not affect viability nor the number of spontaneous liver tumors. Although susceptibility to diethylnitrosamine-induced hepatocarcinogenesis was significantly elevated in the transgenic mice, liver regeneration after partial hepatectomy was delayed compared with wild-type mice, suggesting that gap junctions function not only to suppress excessive cell growth but also to promote cell proliferation when necessary for normal function of tissues. Although the phenotype of Cx32-deficient mice was similar to that of the transgenic mice, the former showed more drastically altered phenotypes, i.e. increased BrdU incorporation in the quiescent liver and development of spontaneous liver tumors. We also established 3T3 fibroblasts from embryos lacking the Cx43 gene and characterized their growth. These fibroblasts showed no difference from the wild type in growth characteristics. From these and other studies, we suggest that gap junctions do not necessarily suppress cell growth but support an optimal growth rate.