[Relation between calcaneal bone mass and lifestyles in young adult women. Influence of experience of delivery and months post delivery]

The aim of this study was to clarify the cross-sectional relation between calcaneal bone mass and lifestyles in healthy pre-menopausal young adult women classified by the experience of pregnancy and the months after delivery. The 457 healthy Japanese women aged 20-39 years living in an urban community underwent a health check up for osteoporosis. Calcaneal bone was measured by ultrasound using the Lunar Achilles, and stiffness was used as an index of bone mass. The information on pregnancy, delivery and lactation, and lifestyles including past and current exercise and frequency of food consumption were collected by a questionnaire. In addition, two-day dietary records were obtained to assess the nutrient intake, and seven-day walking records as an index of physical activities. These subjects were divided into 3 groups according to the experience of pregnancy, and the time after delivery (subgroups of no experience of pregnancy, 12-35 months post-delivery and 36 months or more post-delivery), and the relation between stiffness index and lifestyle factors was examined in the 3 groups. 1) Stiffness correlated significantly with experience of pregnancy, age at menarche, current exercise and frequency of intake of dairy products. 2) In the group without experience of pregnancy, stiffness in women with current exercise habit was significantly higher than women without the habit. Those with past exercise habit, current milk consumption and current calcium intake showed relatively greater stiffness. 3) In the 12-35 months post-delivery group, there was no relation of past and current physical activity to stiffness. For women whose frequency of milk consumption or daily calcium intake were high, the stiffness was significantly greater. In addition, past milk consumption and current frequency of dairy products consumption tended to show higher stiffness. 4) In 36 months or more post-delivery group, women with current exercise habit exhibited significantly higher stiffness than women without the habit. Low calcium intake tended to show low stiffness. These results indicated that the effects of lifestyle on calcaneal bone mass were different depending on the experience of pregnancy and the months after delivery in pre-menopausal young adult women.

[The role of monocyte chemotactic and activating factor (MCAF)/monocyte chemoattractant protein (MCP)-1 in subgroups of rapidly progressive glomerulonephritis]

To elucidate the role of monocyte chemotactic and activating factor (MCAF)/monocyte chemoattractant protein(MCP)-1 in the pathogenesis of rapidly progressive glomerulonephritis (RPGN), we determined the urinary levels of MCAF/MCP-1 in 20 healthy subjects, 30 patients showing RPGN with crescents, and 39 patients with various types of renal diseases without crescents. We divided RPGN into two subgroups, the acute type and the insidious type, with regard to the declination rate of reciprocals of serum creatinine with time as previously reported. In addition, we divided the patients with RPGN into anti-neutrophil cytoplasmic antibody(ANCA)-related diseases and immune complex(IC)-mediated diseases with regard to etiology. Urinary levels of MCAF/MCP-1 were significantly higher in patients with RPGN as compared with those of other renal diseases and healthy volunteers(21.8 +/- 4.5 vs. 11.6 +/- 3.5, 1.0 +/- 0.1 pg/ml creatinine, respectively, p < 0.01, mean +/- SEM). There was no difference in the urinary levels of MCAF/MCP-1 between the acute and insidious types of RPGN patients. In addition, there was no difference in the urinary levels of MCAF/MCP-1 between the patients with ANCA-related and IC-mediated diseases. Urinary levels of MCAF/MCP-1 in patients with RPGN were correlated well with the percentage of both total crescents and fibrocellular/fibrous crescents and the number of CD68-positive infiltrating cells in the interstitium. Immunohistochemical examinations revealed that MCAF/MCP-1 positive cells were detected in tubular epithelial and endothelial cells and mononuclear infiltrated cells in the interstitium. Moreover, elevated urinary MCAF/MCP-1 levels in patients with RPGN, regardless of subgroups, were dramatically decreased during methylprednisolone pulse therapy induced convalescence. These results suggest that MCAF/MCP-1 may be involved in the pathogenesis of RPGN via macrophage recruitment and activation.

Differential regulation of the human insulin gene transcription by GG1 and GG2 elements with GG- and C1-binding factors

Using a human growth hormone reporter system, the introduced mutations in GG1 alone or both GG elements of GG1 and GG2 in the human insulin promoter abolished 94 or 96% of the beta-cell-specific transcriptional activity in a pancreatic islet beta-cell line of MIN6, while the mutations in GG2 or its total deletion abolished 85 or 86% of the transcriptional activity. When linked to the thymidine kinase promoter, mutations in GG1 or both GG elements abolished 74% of the transcriptional activity in MIN6 cells, while the mutations in GG2 or its total deletion abolished 55 or 54%. In the electrophoretic mobility shift assay (EMSA), one nuclear factor was shown to interact with two GG elements, and another C1-binding factor with GG1 and C1. The differential effects of deletions or selective mutations in the GG2 or GG1 sequence in the oligonucleotide probes on the binding activity of GG- or C1-binding factors in EMSA proved the requirement of both GG1 and GG2 or both GG1 and C1, respectively, for the transaction of these two factors. The molecular size of the GG-binding factor was estimated about 30 kDa. Based on these, we conclude that two GG elements contribute, with GG1 more critically than GG2, to the beta-cell-specific transcription of the human insulin gene through transaction with the GG- and C1-binding factors.

Interactive binding to the two principal ligand binding sites of human serum albumin: effect of the neutral-to-base transition

The relationship between the two principal ligand binding sites, sites I and II, on human serum albumin (HSA) was quantitatively and qualitatively examined by equilibrium dialysis and fluorescence spectroscopy. Among the three subsite markers to site I, only the binding of dansyl-L-asparagine (DNSA), which is a subsite Ib marker (K. Yamasaki et al., Biochim. Biophys. Acta 1295 (1996) 147), was inhibited by the simultaneous binding of a site II ligand, such as ibuprofen and diazepam. This indicates that, in contrast to subsite Ib, subsites Ia and Ic do not strongly interact with site II. The thermodynamic characteristics for the coupling reaction between DNSA and ibuprofen and between DNSA and diazepam, which gave positive coupling free energies and negative values for both coupling enthalpy and entropy, indicated that the reaction process was entropically driven. Increase of pH from 6.5 to 8.2 caused an increase in coupling constant and entropy for the mutual antagonism between DNSA and the site II ligands on binding to HSA. The site II ligand-induced red-shift of lambda(max) and solvent accessibility of DNSA in subsite Ib were decreased when the albumin molecule was isomerized from the neutral (N) to the base (B) conformation in the physiological pH region. Based on these findings, we conclude that a 'competitive' like strong allosteric regulation exists for the binding of these two ligands to the N conformer, whereas for the B conformer this interaction can be classified as nearly 'independent'. Since the distance between Trp-214, which resides within the site I subdomain, and Tyr-411, which is involved in site II, is increased by 6 A during the N-B transition (N.G. Hagag et al., Fed. Proc. 41 (1982) 1189), we propose a mechanism for the pH-dependent antagonistic binding between subsite Ib and site II, which involves the transmission of ligand-induced allosteric effects from one site to another site, modified by changes in the spatial relationship of sites I and II caused by the N-B transition.

[Emergency coronary artery bypass grafting with integrated myocardial protection]

In the following retrospective study we reviewed the early postoperative results of emergency CABG; the myocardial management was achieved by utilization of integrated myocardial protection including warm cardioplegic induction, performed at our hospital. From April 1st 1994 to October 30th 1998; 63 patients underwent emergency CABG with integrated myocardial protection. All surgical procedures were performed within 6 hours from the onset of disease or admission transferred from another hospitals. Age ranged 48 to 86 years (mean 69.9 +/- 8.5; 41 male, 22 female). AMI was present in 52, UAP in 11. Preoperative PTCA was done in 20 and IABP was inserted in 53. Cardiogenic shock in 26, mechanical complications in 6, three vessel disease in 48 and LMT disease in 17 was present. Eight patients (12.7%) died in the early postoperative period. Among evaluated risk factors for early postoperative death; the occurrence of cardiogenic shock, mechanical complications of AMI, preoperatively done PTCA and prolonged CPB time were significantly increasing the mortality rate in early postoperative death.

Non-invasive quantitative detection and applications of non-toxic, S65T-type green fluorescent protein in living plants

Green fluorescent protein (GFP) has emerged as a powerful new tool in a variety of organisms. An engineered sGFP(S65T) sequence containing optimized codons of highly expressed eukaryotic proteins has provided up to 100-fold brighter fluorescence signals than the original jellyfish GFP sequence in plant and mammalian cells. It would be useful to establish a non-invasive, quantitative detection system which is optimized for S65T-type GFP, one of the brightest chromophore mutants among the various GFPs. We demonstrate here that highly fluorescent transgenic Arabidopsis can be generated, and the fluorescence intensity of whole plants can be measured under non-disruptive, sterile conditions using a quantitative fluorescent imaging system with blue laser excitation. Homozygous plants can be distinguished from heterozygous plants and fully fertile progenies can be obtained from the analyzed plants. In the case of cultured tobacco cells, GFP-positive cells can be quantitatively distinguished from non-transformed cells under non-selective conditions. This system will be useful in applications such as mutant screening, analysis of whole-body phenomena, including gene silencing and quantitative assessments of colonies from microorganisms to cultured eukaryotic cells. To facilitate the elucidation of protein targeting and organelle biogenesis in planta, we also generated transgenic Arabidopsis that stably express the plastid- or mitochondria-targeted sGFP(S65T). Etioplasts in dark-grown cotyledons and mitochondria in dry seed embryos could be visualized for the first time in transgenic Arabidopsis plants under normal growing conditions.

Apoptosis and remodelling of beta cells by paracrine interferon-gamma without insulitis in transgenic mice

AIMS/HYPOTHESIS

To examine whether interferon-gamma destroys islet beta cells directly or indirectly through lymphocyte activation, or whether direct action of interferon-gamma on beta cells by itself induces diabetes without insulitis.

METHODS

To avoid possible nonspecific breakdown of beta cells by transgenic overexpression of interferon-gamma by the insulin promoter, we generated transgenic mice expressing interferon-gamma under the control of rat glucagon promoter (RGP-IFN-gamma-Tg mice).

RESULTS

The absence of insulitis in RGP-IFN-gamma-Tg mice enabled us to investigate the direct effects of paracrine interferon-gamma. In RGP-IFN-gamma-Tg mice, serum concentrations of interferon-gamma and tumour necrosis factor-alpha (TNF-alpha) were 50 and 6 times higher than those in their littermates, respectively, and glucose-responsive insulin secretion decreased to one-half the level of that in the littermates. Transgenic interferon-gamma induced remodelling of beta cells where apoptosis of many beta cells was compensated by their vigorous regeneration and diabetes did not occur in most of the RGP-IFN-gamma-Tg mice.

CONCLUSION/INTERPRETATION

Interferon-gamma alone is insufficient for the complete destruction of beta cells in vivo, and factors other than interferon-gamma including activated lymphocytes or other cytokines, are necessary in addition to interferon-gamma for the development of Type I (insulin-dependent) diabetes mellitus.

Delayed 5-HT release in the developing cortex of microencephalic rats

Postnatal changes in the fiber distribution and release of 5-HT in the somatosensory cortex (Sm) of methylazoxymethanol acetate (MAM)-induced microencephalic rats were studied. A transient accumulation of serotonergic fibers was observed in the Sm of the control and MAM rats in the first 2 weeks following birth. However, the density of serotonergic fibers was higher in the MAM rats than in the controls, and the distribution pattern of serotonergic fibers was more extensive in the MAM rats. The microdialysis indicated a high basal level and a delayed K+ -evoked 5-HT release in the Sm of MAM rats on postnatal day 10. The present results suggest morphological and functional alterations of serotonergic fibers in the Sm of MAM rats during the critical period of cortical formation.

Treating neonatal rats with 6-hydroxydopamine induced an increase in voluntary alcohol consumption

Brain dopamine (DA) and serotonin (5-HT) neurotransmission have been implicated in the mediation of alcohol-seeking behavior. We examined the effects of treatment of neonatal rats (3 days after birth) with the neurotoxin 6-hydroxydopamine (6-OHDA; 100 microg/10 microl, intracerebroventricularly) on the relationship between the levels of neurotransmitters and alcohol drinking behavior at the age of 14 weeks. 6-OHDA treatment reduced the levels of DA and its metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) in the nucleus accumbens (ACC), frontal cortex, striatum (STR), tegmentum/substantia nigra, and dorsal raphe nucleus. 5-HT levels in the ACC and STR were increased in the 6-OHDA-treated rats. 6-OHDA-treated rats showed increased alcohol consumption. There was a significant change in the ratio of [5-hydroxyindoleacetic acid]/[5-HT] in the ACC and STR of the treated rats, but no difference in the ratio of [DOPAC]/[DA] between the sham-operated controls and treated rats. 6-OHDA-treated rats had dopaminergic dysfunction in the five brain regions related to the reward system, in part, and a decrease in 5-HT turnover, including the accumulation of 5-HT in the ACC and STR. Furthermore, basal extracellular releases of DA and 5-HT of the ACC were significantly lower in the 6-OHDA-treated rats, compared with the controls. It was suggested that alcohol seeking behavior is associated with the alterations of dopaminergic neurons and the release of 5-HT in the mesocorticolimbic system.

Effects of oral supplementation with evening primrose oil for six weeks on plasma essential fatty acids and uremic skin symptoms in hemodialysis patients

Abnormalities in plasma composition of essential fatty acids (EFAs) may be associated with the etiology of pruritus and other skin problems in patients undergoing hemodialysis. To study whether an oral supplementation with omega-6 (n-6) EFAs would restore deranged plasma EFAs and ameliorate skin symptoms, 9 and 7 dialysis patients were randomly assigned to receive either gamma-linolenic acid (GLA)-rich evening primrose oil (EPO) or linoleic acid (LA) (2 g/day each) for 6 weeks. Plasma concentrations of EFA were analyzed by gas chromatography and uremic skin symptoms were assessed for dryness, pruritus and erythema by questionnaire and visual inspection in a double-blind manner. The patients given EPO exhibited a significant (p < 0.05) increase in plasma dihomo-gamma-linolenic acid (a precursor of anti-inflammatory prostaglandin E1) with no concomitant change in plasma arachidonic acid (a precursor of pro-inflammatory prostaglandin E2 and leukotriene B4). In contrast, those given LA exhibited a significant (p < 0.05) increase in LA but not in any other n-6 EFAs, whereas they exhibited a significant (p < 0.05) decrease in plasma docosahexaenoic acid. The patients given EPO showed a significant (p < 0.05) improvement in the skin scores for the three different uremic skin symptoms over the baseline values and a trend toward a greater improvement (0.05 < p < 0.1) in pruritus scores than those given LA. Results indicate that GLA-rich EPO would be a more favorable supplemental source than LA in terms of shifting eicosanoid metabolism toward a less inflammation status through modifying plasma concentrations of their precursor n-6 EFAs. Further studies are required to confirm the efficacy and safety of EPO therapy for the treatment of uremic pruritus.

Infrequent detectable somatic mutations of the RET and glial cell line-derived neurotrophic factor (GDNF) genes in human pituitary adenomas

RET is a receptor tyrosine kinase expressed in neuroendocrine cells and tumors. RET is activated by a ligand complex comprising glial cell line-derived neurotrophic factor (GDNF) and GDNF receptor-alpha (GDNFR-alpha). Activating mutations of the RET proto-oncogene were found in multiple endocrine neoplasia (MEN) 2 and in sporadic medullary thyroid carcinoma and pheochromocytoma of neuroendocrine origin. Mutations of the RET proto-oncogene and the glial cell line-derived neurotrophic factor (GDNF) gene were examined in human pituitary tumors. No mutations of the RET proto-oncogene including the cysteine-rich region or codon 768 and 918 in the tyrosine kinase domain were detected in 172 human pituitary adenomas either by polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP) or by PCR-restriction fragment length polymorphism (RFLP). Further, somatic mutations of the GDNF gene in 33 human pituitary adenomas were not detected by PCR-SSCP. One polymorphism of the GDNF gene at codon 145 of TGC or TGT was observed in a prolactinoma. The RET proto-oncogene message was detected in a normal human pituitary gland or 4 of 4 human pituitary adenomas with reverse transcription (RT)-PCR, and in rodent pituitary tumor cell lines with Western blotting. The expression of GDNF gene was detected in 1 of 4 human somatotroph adenomas, 1 of 2 corticotroph adenomas, and 2 of 6 rodent pituitary tumor cell lines with RT-PCR. Based on these, it is concluded that somatic mutations of the RET proto-oncogene or the GDNF gene do not appear to play a major role in the pituitary tumorigenesis in examined tumors.

The effects of oestrogen and progesterone on serotonin and its metabolite in the lateral septum, medial preoptic area and ventromedial hypothalamic nucleus of female rats

The effects of sex steroid hormones on serotonin and its metabolite, 5-hydroxyindole-3-acetic acid (5-HIAA) in the lateral septal nucleus (LS), the medial preoptic area (MPA) and the ventromedial nucleus of the hypothalamus (VMH) of female rats were investigated, using immunohistochemistry and high-performance liquid chromatography (HPLC). Female rats were divided into three groups: ovariectomized rats (OVX group); OVX-rats treated with estradiol benzoate alone (E2 group); and OVX-rats treated with E2 plus progesterone (E2 + P group). We analysed the density of serotonin-immunoreactive fibres with a computer-assisted image analysis system, and measured the tissue concentrations of serotonin and 5-HIAA. Many serotonin-immunoreactive fibres were observed in the LS, MPA and VMH in all three groups. The density of serotonin-immunoreactive fibres in the MPA and VMH was significantly lower in the E2 and E2+P groups compared to the OVX group, whereas the LS showed no detectable differences among the three groups. In the HPLC study, the concentrations of serotonin in the MPA and VMH of the E2 and E2+P groups were significantly lower than that in the OVX group. There was no significant difference in the concentration of serotonin in the LS. The concentration of 5-HIAA and the ratio of 5-HIAA/serotonin in the LS, MPA and VMH showed no significant differences among the OVX, E2 and E2+P groups. The present results suggest that E2 priming for sexual behaviour can affect the serotonergic system by decreasing serotonin content, but not the turnover rate, in the MPA and VMH of female rats.

Age-related degeneration of the serotoninergic fibers in the zitter rat brain

The serotonin neuron system was studied using immunohistochemical and neurochemical techniques in zitter mutant rats aged 1-14 months, which are characterized by abnormal metabolism of superoxides. The morphology of the serotoninergic neuron system and the serotonin level in the zitter rat were compared to those of age-matched Sprague-Dawley (SD) rats. Up to age 4 month, the density and distribution of serotoninergic fibers in the zitter rat brain were similar to those of control rats. However, several serotoninergic fibers with abnormal morphology, characterized by swollen varicosities, were observed in the cerebral cortex and caudate putamen of 6-month-old zitter rats. The density and distribution of these fibers in other regions of the brain were similar to those of control rats. The abnormal serotoninergic fibers increased in number and extended into other regions of the brain such as the thalamus, hippocampus, and vestibular nucleus. On the other hand, the density of normal serotoninergic fibers decreased throughout the brain of the 14-month-old zitter rat. Abnormal serotoninergic fibers have also been reported in the brain of normal older (24 months) SD rats. Neurochemical analysis revealed lower levels of serotonin, and 5-hydroxyindoleacetic acid, in all cortical areas (prefrontal, parietal, and occipital cortices), the caudate putamen, and the hippocampus of 12-month-old zitter rats. Levels differed significantly in the parietal cortex and hippocampus between the zitter and SD rats. Based on the morphological and neurochemical similarities, the present results suggest that age-related degeneration of serotoninergic fibers occurs in the zitter rat brain. Furthermore, degeneration of serotoninergic fibers appears to be induced by superoxide species. Thus, the zitter rat may provide a good model for studying the neurotoxic effects of superoxide species on the serotoninergic neuron system.

Clinical application of ultrasound 3 D imaging system in lesions of the gastrointestinal tract

BACKGROUND AND STUDY AIMS

The usefulness of the ultrasound 3 D imaging system (3 D-EUS) is reported. 3 D-EUS using an ultrasonic probe has been introduced as a result of the developments in 3 D-EUS (EU-IP) by Olympus. The 3 D-EUS image was reconstructed by composing the radial and linear images produced by 40 slices of radial image, which were obtained by spiral scanning of the ultrasonic probe in the sheath. This system also allowed numerous functions, such as multifreeze, high-resolution images, measurement etc. for a definitive diagnosis.

RESULTS

In the past three years, 190 lesions of the gastrointestinal tract were examined by 3 D-EUS. The rate of correct approach to the lesions was 89% (overall). The most inappropriate approach was a result of the oblique probe approach, or lesions sited in difficult positions. The radial, linear and 3 D images were generally good. Pulsation, deep attenuation and small lesions caused the worst images. Most small lesions were imaged thoroughly with radial imaging and so no significant changes can be seen with 3 D images. High-resolution images were more precise and finer than with plain EUS.

CONCLUSIONS

3 D-EUS contributed more useful and finer images for the EUS examinations. Gastrointestinal lesions are generally well displayed and recognizable. There are still a few problems to be solved for proper imaging, but there should be positive advances in diagnostic ability with the development of this system.

Dihydropyridine type calcium channel blocker-induced turbid dialysate in patients undergoing peritoneal dialysis

We previously reported that manidipine, a new dihydropyridine type calcium channel blocker, produced chylous peritoneal dialysate being visually indistinguishable from infective peritonitis in 5 patients undergoing continuous ambulatory peritoneal dialysis (CAPD) [Yoshimoto et al. 1993]. To study whether such an adverse drug reaction would also be elicited by other commonly prescribed calcium channel blockers in CAPD patients, we have conducted postal inquiry to 15 collaborating hospitals and an institutional survey in International Medical Center of Japan as to the possible occurrence of calcium channel blocker-associated non-infective, turbid peritoneal dialysate in CAPD patients. Our diagnostic criteria for drug-induced turbidity of dialysate as a) it developed within 48 h after the administration of a newly introduced calcium channel blocker to the therapeutic regimen, b) absence of clinical symptoms of peritoneal inflammation (i.e., pyrexia, abdominal pain, nausea or vomiting), c) the fluid containing normal leukocyte counts and being negative for bacterial and fungal culture of the fluid, and d) it disappeared shortly after the withdrawal of the assumed causative agent. Results showed that 19 out of 251 CAPD patients given one of the calcium channel blockers developed non-infective turbid peritoneal dialysis that fulfilled all the above criteria. Four calcium channel blockers were suspected to be associated with the events: benidipine [2 out of 2 (100%) patients given the drug], manidipine [15 out of 36 (42%) patients], nisoldipine [1 out of 11 (9%) patients] and nifedipine [1 out of 159 (0.6%)] in descending order of frequency. None of the patients who received nicardipine, nilvadipine, nitrendipine, barnidipine and diltiazem (25, 7, 2, 1 and 8 patients, respectively) exhibited turbid dialysate. In conclusion, we consider that certain dihydropyridine type calcium channel blockers would cause turbid peritoneal dialysate being similar to that observed in patients developing infective peritonitis. To avoid unnecessary antibiotic therapy the possibility of this adverse reaction should be ruled out whenever a CAPD patient receiving a dihydropyridine type calcium channel blocker develops turbid dialysate.

Histamine H1-receptor-mediated increase in the Ca2+ transient without a change in the Ca2+ current in electrically stimulated guinea-pig atrial myocytes

The effects of histamine on the intracellular Ca2+ concentration ([Ca2+]i), action potential and membrane currents were assessed in single atrial myocytes prepared from guinea-pigs. Histamine caused a concentration-dependent increase in the [Ca2+]i transient in indol/AM loaded myocytes when stimulated electrically at 0.5 Hz. However, the maximum increase in [Ca2+]i transient produced by histamine was less than 50% of that elicited by isoprenaline. The histamine-induced increase in [Ca2+]i transient was significantly inhibited by chlorpheniramine, but not by cimetidine. Pretreatment with nifedipine nearly completely suppressed the histamine-induced increase in [Ca2+]i transient. Cyclopiazonic acid did not affect the histamine response. In the whole-cell current-clamp mode of the patch-clamp method, both histamine and isoprenaline prolonged action potential duration (APD) in atrial myocytes. In the presence of Co2+ or nifedipine, the isoprenaline-induced APD prolongation was abolished and an APD shortening effect was manifested, while histamine still increased APD. The APD prolongation elicited by histamine was reversed by chlorpheniramine. In the voltage-clamp mode, the histamine-sensitive membrane current was inwardly rectifying and reversed close to the calculated value of the K+ equilibrium potential. Histamine had no apparent effect on L-type Ca2+ current, in contrast to the pronounced effect of isoprenaline. These results indicate that in guinea-pig atrial myocytes stimulation of H1-receptors with histamine does not directly activate Ca2+ channels but causes an elevation of [Ca2+]i transient by increasing Ca2+ influx through the channels during the prolonged repolarization of action potentials resulting from inhibition of the outward K+ current.

Abrogation of autoimmune diabetes in nonobese diabetic mice and protection against effector lymphocytes by transgenic paracrine TGF-beta1

Paracrine effect of transforming growth factor-beta1 (TGF-beta1) on autoimmune insulitis and diabetes was studied by transgenic production of the active form of porcine TGF-beta1 (pTGF-beta1) in pancreatic islet (islet) alpha cells in nonobese diabetic (NOD) mice under the control of rat glucagon promoter (RGP) (NOD-RGP-TGF-beta1). None of 27 NOD-RGP-TGF- beta1 mice developed diabetes by 45 wk of age, in contrast to 40 and 71% in male and female nontransgenic mice, respectively. None of the NOD-RGP-TGF-beta1 mice developed diabetes after cyclophosphamide (CY) administration. Adoptive transfer of splenocytes of NOD-RGP-TGF-beta1 mice to neonatal NOD mice did not transfer diabetes after CY administration. Adoptive transfer of three types of diabetogenic lymphocytes to NOD-RGP-TGF-beta1 and nontransgenic mice after CY administration led to the lower incidence of diabetes in NOD-RGP-TGF-beta1 mice versus that in nontransgenic mice: 29 vs. 77% for diabetogenic splenocytes, 25 vs. 75% for islet beta cell-specific Th1 clone cells, and 0 vs. 50% for islet beta cell-specific CD8(+) clone cells, respectively. Based on these, it is concluded that autoimmune diabetes in NOD mice is not a systemic disease and it can be completely prevented by the paracrine TGF-beta1 in the islet compartment through protection against CD4(+) and CD8(+) effector lymphocytes.

Analysis of loss of heterozygosity on chromosome 11 and infrequent inactivation of the MEN1 gene in sporadic pituitary adenomas

To investigate the role of tumor suppressor genes in sporadic pituitary adenomas, we first analyzed loss of heterozygosity on 11q13 with microsatellite analysis in 31 tumors. Loss of heterozygosity on 11q13 was detected in 1 mixed GH/PRL adenoma, and the somatic 22-bp deletion of the multiple endocrine neoplasia type 1 (MEN1) gene encoding menin was detected in this tumor. Trisomy 11 suggested by the decreased mean allelic ratios of 66% or 65% for 16 or 13 microsatellite markers, respectively, in 2 of 31 pituitary adenomas was confirmed by interphase fluorescence in situ hybridization. Screening for mutations of the MEN1 gene did not find mutations with PCR-single strand conformation polymorphism analysis in other pituitary adenomas retaining heterozygosity on 11q13. Based on these, it is concluded that inactivation of the MEN1 gene comprises a rare etiology for tumorigenesis of the pituitary gland, and that trisomy 11 or another gene(s) may contribute to the pathogenesis of sporadic pituitary adenomas.

Frequent overexpression of the cyclin D1 oncogene in invasive lobular carcinoma of the breast

Invasive lobular carcinoma comprises approximately 10% of human mammary cancers, yet little is known about the molecular basis of this carcinoma. Because cyclin D1 plays a role in the pathogenesis of breast carcinomas of the ductal type, we hypothesized that this confirmed oncogene might also participate in the development of lobular carcinomas. We sought to determine the frequency of cyclin D1 protein overexpression in invasive lobular carcinoma, to investigate the cause of the protein accumulation, and to identify the effects of high levels of the protein on the regulation of the cell cycle. The study group comprises 27 indisputable cases of invasive lobular carcinoma showing varying degrees of cytological atypia. Immunohistochemical staining using well-characterized monoclonal and polyclonal antibodies disclosed cyclin D1 protein in the majority of the invasive lobular carcinoma cells in 80% of the tumors. In marked contrast, only rare cells of the noninvasive component (lobular carcinoma in situ) in the same tissue sections showed positive staining. Southern blotting of nine cases did not reveal evidence of cyclin D1 gene amplification. Immunohistochemical staining for Ki-67, a protein present in all dividing cells, showed that most cells positive for cyclin D1 did not stain for Ki-67. We conclude that the vast majority of invasive lobular carcinomas show overexpression of cyclin D1 protein. The absence of cyclin D1 protein expression in the noninvasive cells suggests that the molecule plays a role in the progression to the invasive form of lobular carcinoma. In contrast to the ductal types of breast cancer, cyclin D1 gene amplification does not seem to cause the cyclin D1 protein overexpression in lobular cancers. The lack of correlation between cyclin D1 and Ki-67 expression suggests that the cyclin D1 oncogene acts through mechanisms other than simple acceleration of the cell cycle clock in this subtype of human breast carcinoma.

Granular cell tumor of the pituitary stalk

A 52-year-old woman, who had been treated for Parkinson disease for 2 years, was found to have a suprasellar granular cell tumor. The clinical and pathological features, as well as some of the nosologic problems of this rare tumor of the neurohypophysis are briefly discussed.

Effects of age and ethanol on dopamine and serotonin release in the rat nucleus accumbens

Neural functions in the nucleus accumbens (ACC) play an important role in alcohol drinking behavior. In the present study, we observed the effects of age and ethanol (EtOH) on dopamine (DA) and serotonin (5-HT) release in the ACC of freely moving 4-, 10-, and 16-month-old rats using brain microdialysis techniques. After co-perfusion with 200 mM ethanol, ACC DA, and 5-HT release were decreased significantly in 16-month-old rats compared to those at 4 months old. ACC DA and 5-HT neurons of aged rats were less sensitive to ethanol. On the other hand, both basal extracellular DA and 5-HT release in the ACC were significantly higher in 16-month-old than in 4-month-old rats. Therefore, aging results in opposite changes in basal and alcohol-induced DA and 5-HT release in the ACC.

6R-L-erythro-5,6,7,8-tetrahydrobiopterin is involved in brain vulnerability of senescence-accelerated mouse during the processes of aging

The effects of age on the dopamine (DA) turnover and 6R-L-erythro-5,6,7,8-tetrahydrobiopterin (6R-BH4), a cofactor for monooxygenases, were investigated in the striatum and midbrain of the senescence accelerated mouse (SAM) at 6, 12 and 15 months old. 6R-BH4 and DA levels were decreased significantly in the striatum of 15-month-old SAM-P/1 (senescence accelerated prone) mice. At 12 months old, DA level was decreased significantly in the striatum of SAM-P/1 compared with SAM-R/1 (senescence accelerated resistant) mice. The reduction of striatal DA level was shown to be related to the depletion of 6R-BH4 in the striatum during the processes of aging. Age-related decreases in striatal dopamine function occurred in SAM-P/1 mice earlier than in the SAM-R/1 mice. The striatal [DOPAC]/[DA] ratio, as the index of DA turnover, was increased significantly in the 15-month-old SAM-P/1 mice. On the other hand, the DA, 6R-BH4 levels and the ratio of [DOPAC]/[DA] did not show any changes in the midbrain of SAM-P/1 and SAM-R/1 during the processes of aging. It was suggested that brain vulnerability with aging may be associated with the levels of 6R-BH4.

Absence of germ-line mutations of the multiple endocrine neoplasia type 1 (MEN1) gene in familial pituitary adenoma in contrast to MEN1 in Japanese

Germ-line mutations of the MEN1 gene were analyzed in five cases of familial and four cases of sporadic multiple endocrine neoplasia type 1 (MEN-1), six cases in three independent pedigrees of familial pituitary adenoma without MEN-1, and three cases of familial isolated primary hyperparathyroidism (FIHP) in Japanese. Eight different types of germ-line mutations in all nine cases of MEN-1 were distributed in exons 2, 3, 7, and 10 and intron 7 of the MEN1 gene. Loss of heterozygosity (LOH) on 11q13 was detected in all nine tumors of these cases with microsatellite analysis. No germ-line mutation of the MEN1 gene was detected in three pedigrees of familial pituitary adenoma and three cases of FIHP. LOH on 11q13 was detected in two cases in one pedigree of familial pituitary adenoma, and one of them showed a heterozygous somatic mutation of the MEN1 gene. No LOH on 11q13 was detected in three cases of FIHP. Based on these, we conclude that the loss of function of menin is etiological for familial or sporadic MEN-1, but not for FIHP or most familial pituitary adenoma without MEN-1.

Application of the reversed elephant trunk technique during total thoracoabdominal replacement in patients with Marfan's syndrome

The reversed elephant trunk operation has been applied in patients with extensive aortic involvement as a scheduled staged operation. We report application of the same technique in two patients with Marfan's syndrome. The two patients underwent total replacement of the thoracoabdominal aorta for a DeBakey IIIb aortic dissection. The proximal end of the prosthetic graft was invaginated to facilitate future proximal operation. No complication related to the trunk had been observed during the follow-up period.