Preferential arborization of dendrites and axons of parvalbumin- and somatostatin-positive GABAergic neurons within subregions of the mouse claustrum

The claustrum coordinates the activities of individual cortical areas through abundant reciprocal connections with the cerebral cortex. Although these excitatory connections have been extensively investigated in three subregions of the claustrum-core region and dorsal and ventral shell regions-the contribution of GABAergic neurons to the circuitry in each subregion remains unclear. Here, we examined the distribution of GABAergic neurons and their dendritic and axonal arborizations in each subregion. Combining in situ hybridization with immunofluorescence histochemistry showed that approximately 10% of neuronal nuclei-positive cells expressed glutamic acid decarboxylase 67 mRNA across the claustral subregions. Approximately 20%, 30%, and 10% of GABAergic neurons were immunoreactive for parvalbumin (PV), somatostatin (SOM), and vasoactive intestinal polypeptide, respectively, in each subregion, and these neurochemical markers showed little overlap with each other. We then reconstructed PV and SOM neurons labeled with adeno-associated virus vectors. The dendrites and axons of PV and SOM neurons were preferentially localized to their respective subregions where their cell bodies were located. Furthermore, the axons were preferentially extended in a rostrocaudal direction, whereas the dendrites were relatively isotropic. The present findings suggest that claustral PV and SOM neurons might execute information processing separately within the core and shell regions.

A possible mechanism of the nucleus accumbens and ventral pallidum 5-HT1B receptors underlying the antidepressant action of ketamine: a PET study with macaques

Ketamine is a unique anesthetic reagent known to produce various psychotic symptoms. Ketamine has recently been reported to elicit a long-lasting antidepressant effect in patients with major depression. Although recent studies provide insight into the molecular mechanisms of the effects of ketamine, the antidepressant mechanism has not been fully elucidated. To understand the involvement of the brain serotonergic system in the actions of ketamine, we performed a positron emission tomography (PET) study on non-human primates. Four rhesus monkeys underwent PET studies with two serotonin (5-HT)-related PET radioligands, [(11)C]AZ10419369 and [(11)C]DASB, which are highly selective for the 5-HT1B receptor and serotonin transporter (SERT), respectively. Voxel-based analysis using standardized brain images revealed that ketamine administration significantly increased 5-HT1B receptor binding in the nucleus accumbens and ventral pallidum, whereas it significantly reduced SERT binding in these brain regions. Fenfluramine, a 5-HT releaser, significantly decreased 5-HT1B receptor binding, but no additional effect was observed when it was administered with ketamine. Furthermore, pretreatment with 2,3-dihydroxy-6-nitro-7-sulfamoylbenzo(f)quinoxaline (NBQX), a potent antagonist of the glutamate α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor, blocked the action of ketamine on the 5-HT1B receptor but not SERT binding. This indicates the involvement of AMPA receptor activation in ketamine-induced alterations of 5-HT1B receptor binding. Because NBQX is known to block the antidepressant effect of ketamine in rodents, alterations in the serotonergic neurotransmission, particularly upregulation of postsynaptic 5-HT1B receptors in the nucleus accumbens and ventral pallidum may be critically involved in the antidepressant action of ketamine.

Mental fatigue-induced decrease in levels of several plasma amino acids

To investigate the relation between plasma amino acid levels and mental fatigue, we measured the plasma concentrations of 20 amino acids in 9 healthy volunteers before and after a fatigue-inducing mental task session for 8 hr. As fatigue-inducing mental tasks, the subjects performed an advanced trail making test, a Japanese KANA pick up test, and a mirror drawing test. As a control, 8-hr relaxation session was performed in the same subjects at an interval of 4 weeks. Immediately after the fatigue session, the plasma levels of branched-chain amino acids, tyrosine, cysteine, methionine, lysine, and arginine were below those after a relaxation session. The values for other blood parameters including total protein, albumin, glucose, and total cholesterol did not show any differences between the 2 sessions. These results indicate that mental fatigue may be characterized by a decrease in the plasma level of these amino acids.

Relationship between plasma cyclo (His-Pro), a neuropeptide common to processed protein-rich food, and C-peptide/insulin molar ratio in obese women

Cyclo (His-Pro) (CHP) is a gut-brain peptide whose plasma levels in humans are increased after glucose ingestion and preferentially altered by oral glucose ingestion compared to intravenous administration in rats, suggesting a role in the enteroinsular response to nutrient ingestion. We were interested in examining levels of CHP in women of differing weights and comparing these levels to various parameters of insulin secretion. Plasma from 26 fasting, nondiabetic women ranging from 21 to 70 years of age and weighing 43 to 114 kg was assayed for CHP. Insulin and C-peptide levels were measured in 17 of the 26. Fasting CHP levels were elevated in obese compared to nonobese women (2075+/-144 vs. 905+/-187 pg/ml; p < 0.001) and were related by regression analysis to weight (r = 0.668, p < 0.001) and body mass index (r = 0.636, p = 0.001). The fasting C peptide/insulin molar ratio, which may be used as an estimate of hepatic insulin clearance (HIC), was inversely related to CHP levels (r = -0.568, p = 0.017). We conclude CHP levels are increased in obese women and inversely related to their C-peptide/insulin molar ratio. The elevation of CHP in those with a decrease in this estimate of HIC (obese) is interesting as the greater insulin response seen in normal persons after oral glucose compared to intravenous glucose has been postulated to be due to a decrease in HIC by some gut factor. The presence of such a factor in excess in the obese might explain part of their hyperinsulinemia.

Expression and regulation of type II iodothyronine deiodinase in human thyroid gland

We have studied the expression of type II iodothyronine deiodinase (DII) in human thyroid tumors and cultured human thyroid cells to elucidate the mechanisms involved in the regulation of DII expression in human thyroid gland. Three cases with hyperfunctioning thyroid adenoma, including a case that showed an activating mutation of G(s)alpha with a constitutive activation of cAMP production in cultured cells, and six cases with papillary thyroid carcinoma were analyzed in the present study. Free T(3) was increased, whereas free T(4) was within the normal range in all patients with hyperfunctioning thyroid adenoma. Thyroid tumor tissue and surrounding nontumor tissue were obtained at the time of surgery, and DII expression was compared between tumor tissue and nontumor tissue in each case. Northern analysis demonstrated the presence of DII messenger RNA (mRNA) approximately 7.5 kb in size in all of the tumor and nontumor tissues. DII mRNA and DII activity in hyperfunctioning thyroid adenoma were significantly increased compared with those in nontumor tissue in each case. In contrast, DII mRNA and DII activity in papillary thyroid carcinoma were decreased compared with those in nontumor tissue in each case. DII mRNA and DII activity in cultured human thyroid cells were significantly stimulated by TSH in a dose-dependent manner. The promoter activity of the human DII gene including the complete cAMP response element, transfected to cultured human thyroid cells, was stimulated by (Bu)(2)cAMP. In summary, these results suggest that DII expression in human thyroid gland is regulated at the transcriptional level through the TSH receptor-G(s)alpha-cAMP regulatory cascade, which may be related to the increase in circulating T(3) level in patients with Graves' disease and hyperfunctioning thyroid adenoma.

Expression of thyrotropin receptors in rat thymus

Thymic hyperplasia is associated with Graves' disease. It has been demonstrated that thyrotropin receptors are expressed in human thymus, and thymic thyrotropin receptors are suggested to be involved in the pathophysiology of Graves' disease. We have studied whether thyrotropin receptors are expressed in rat thymic tissue. Thyrotropin receptor mRNA was demonstrated in 5-day-old, 10-day-old, 20-day-old and adult rat thymus by reverse transcription polymerase chain reaction. Thyrotropin receptor mRNA was also demonstrated in cultured rat thymic epithelial cells. Thyrotropin stimulated cyclic AMP production in cultured rat thymic epithelial cells, suggesting the expression of functional thyrotropin receptors. The present results indicate that thyrotropin receptors are expressed in rat thymus.

Identification of monoclonal insulin autoantibodies in insulin autoimmune syndrome associated with HLA-DRB1*0401

We have characterized HLA and insulin autoantibodies in a Japanese female patient with insulin autoimmune syndrome. Serological HLA typing demonstrated the patient had HLA-DR4, and DNA typing showed she had HLA-DRB1*0401 which has not been reported in patients with insulin autoimmune syndrome in Japan. A single binding affinity of insulin autoantibodies was demonstrated by Scatchard analysis and immunoglobulin class of insulin autoantibodies was exclusively IgG-kappa. HLA-DRB1*0406 is strikingly associated with patients with insulin autoimmune syndrome who have polyclonal insulin autoantibodies. The present report demonstrated the first Japanese patient with insulin autoimmune syndrome carrying HLA-DRB1*0401 who was revealed to have monoclonal insulin autoantibodies. The present results indicate that HLA molecules are the major determinants of polyclonal insulin autoantibodies and monoclonal insulin autoantibodies in insulin autoimmune syndrome.

Thyrotropin receptors in brown adipose tissue: thyrotropin stimulates type II iodothyronine deiodinase and uncoupling protein-1 in brown adipocytes

It has been demonstrated that TSH receptors are expressed not only in thyroid gland but also in extrathyroidal tissues. Brown adipose tissue of guinea pig has been reported to express TSH receptor messenger RNA (mRNA), but the physiological roles of TSH receptors in brown adipose tissue have not been understood. We studied the expression and function of TSH receptors in rat brown adipose tissue and cultured rat brown adipocytes. Northern analysis demonstrated the expression of TSH receptor mRNA in rat brown adipose tissue and cultured rat brown adipocytes. TSH receptor mRNA in rat brown adipose tissue was decreased by cold exposure of the rat, and its mRNA in cultured rat brown adipocytes was also decreased by incubation with TSH or (Bu)(2)cAMP. TSH increased the intracellular cAMP concentration in cultured rat brown adipocytes in a dose dependent manner. Type II iodothyronine deiodinase mRNA, its activity, and uncoupling protein-1 mRNA in cultured rat brown adipocytes were significantly increased by incubation with TSH in a dose-dependent manner. These results suggest the expression of functional TSH receptors in brown adipose tissue, which may be involved in regulation of the expression of type II iodothyronine deiodinase and uncoupling protein-1.

Thyroid hormone activation in human vascular smooth muscle cells: expression of type II iodothyronine deiodinase

Thyroid hormone has been reported to have significant effects on the peripheral vascular system, including relaxation of vascular smooth muscle cells and antiatherosclerotic effects. To exert its biological activity, thyroxine, which is a major secretory product of thyroid gland, needs to be converted to 3,5,3'-triiodothyronine (T(3)) by iodothyronine deiodinase. Type I iodothyronine deiodinase (DI) is widely distributed and maintains circulating T(3) level, whereas type II iodothyronine deiodinase (DII) is present in a limited number of tissues to provide local intracellular T(3). In the present study, we have identified iodothyronine deiodinase in cultured human coronary artery smooth muscle cells (hCASMCs) and human aortic smooth muscle cells (hASMCs). All of the characteristics of the deiodinating activity in hCASMCs and hASMCs were compatible with DII. Northern analysis demonstrated that DII mRNA was expressed in both hCASMCs and hASMCs, and DII mRNA levels as well as DII activities were rapidly increased by dibutyryl-cAMP or forskolin. These data demonstrate, for the first time, the expression of DII in human vascular smooth muscle cells, which is regulated by a cAMP-mediated mechanism. The present results suggest a previously unrecognized role of local T(3) production by DII in the pathophysiology of human vascular smooth muscle cells.

Expression of type II iodothyronine deiodinase in brain tumors

Type II iodothyronine deiodinase (DII) messenger ribonucleic acid (mRNA) and its activity have been demonstrated in human normal brain. Although DII activity has been demonstrated in brain tumors, expression of DII mRNA has not been studied in these tumors. To investigate the mechanisms involved in the expression of DII activity in brain tumors, we studied DII mRNA and DII activity in astrocytoma (two cases), glioblastoma (three cases), and oligodendroglioma (one case). DII mRNA, the size of which was indistinguishable from that in control cerebral cortical tissue, was demonstrated in all of the brain tumors tested, although the intensity of the hybridization signal showed wide variation among the tumors. DII activity was also detected in all tumors. DII mRNA and DII activity were highest in the tissue from oligodendroglioma. A significantly positive correlation was observed between DII mRNA and DII activity in these tumors (r = 0.94; P < 0.01), suggesting that DII expression in brain tumors is regulated at the pretranslational level. The present results demonstrate, for the first time, that DII mRNA as well as DII activity are expressed in brain tumors, and that DII mRNA is significantly correlated with DII activity in those tissues.

[A case of acute respiratory distress syndrome induced by fulminant influenza A (H3 N2) pneumonia]

We report a rare case of acute respiratory distress syndrome (ARDS) induced by Influenza A (H3 N2) without secondary microbiological infection. A 69-year-old woman was admitted to our hospital because of cough and severe dyspnea. We diagnosed ARDS, because of the severe respiratory failure resistant to high-dose oxygen, the diffuse bilateral infiltrates without cardiomegaly on chest radiography, and the normal pulmonary artery wedge pressure. This patient was treated with high doses of methylprednisolone, antibiotics, globulins, urinastatin, neutrophilic elastase inhibitor, nitric oxide inhalation, and extracorporeal membrane oxygenation, but died on the thirteenth hospital day. Our final diagnosis was ARDS induced by fulminant influenza (A/Hong Kong/68 (H3 N2)) virus pneumonia, because the antibody titers of H3 N2 influenza of paired sera showed a 128-fold increase.

Expression and regulation of type II iodothyronine deiodinase in cultured human skeletal muscle cells

T4, which is a major secretory product of the thyroid gland, needs to be converted to T3 by iodothyronine deiodinase to exert its biological activity. After the molecular cloning of human type II iodothyronine deiodinase (DII) complementary DNA, DII expression was unexpectedly detected in human skeletal muscle tissue. In the present study, we have identified DII activity and DII messenger ribonucleic acid (mRNA) in cultured human skeletal muscle cells and studied the mechanisms involved in the regulation of DII expression in those cells. All of the characteristics of the deiodinating activity in cultured human skeletal muscle cells were compatible with those of DII. Northern analysis has demonstrated that DII mRNA, approximately 7.5 kb in size, was expressed in cultured human skeletal muscle cells. DII mRNA and DII activity were rapidly increased by (Bu)2cAMP, forskolin, or beta-adrenergic agonists and were negatively regulated by thyroid hormones in cultured human skeletal muscle cells. Although interleukin-1beta and interleukin-6 did not decrease DII expression in cultured human skeletal muscle cells, tumor necrosis factor-alpha decreased DII expression in those cells in a dose-dependent manner. These data have demonstrated, for the first time, that DII activity and DII mRNA are present in cultured human skeletal muscle cells, and that the DII expression is stimulated by beta-adrenergic mechanisms through a cAMP-mediated pathway and is negatively regulated by thyroid hormones and tumor necrosis factor-alpha.

Hepatic insulin clearance increases after weight loss in obese children and adolescents

BACKGROUND

Obesity is a rapidly increasing health problem among US youth. Hyperinsulinemia is associated with obesity and has been found to be a contributory factor for the development of cardiovascular disease in the obese. It has been suggested that hyperinsulinemia of obesity is a result of increased insulin secretion caused by insulin resistance. However, it has been shown in adults that decreased hepatic insulin clearance (HIC) is the primary cause of hyperinsulinemia in this population.

METHODS

We studied 15 obese children and adolescents (11 F, 4 M; 8.6 to 18.1 years) before and 10 weeks after their enrollment in a multidisciplinary weight reduction program, which included a protein-sparing modified fast, a moderate intensity progressive exercise program, and a behavior-modification intervention.

RESULTS

All patients lost weight (P < 0.05). Measurements of immunoreactive insulin (IRI) and C-peptide reactivity (CPR) were performed before the program and at 10 weeks. IRI levels dropped significantly, whereas CPR levels did not change. CPR/IRI molar ratios, considered an indirect estimation of HIC, rose significantly after weight loss.

CONCLUSIONS

Our data suggest that hyperinsulinemia seen in obese children and adolescents is caused by decreased HIC. The cause for this decrease remains unknown, but it is reversible upon weight loss.

A nondenaturing protein map of human plasma proteins correlated with a denaturing polypeptide map combining techniques of micro two-dimensional gel electrophoresis

Human plasma proteins were separated by combining four types of two-dimensional electrophoresis (2-DE) techniques to obtain systematic information on proteins and their constituent polypeptides. A micro gel system was employed to facilitate the analysis. A plasma sample was first analyzed under nondenaturing conditions of electrophoresis (Type I 2-DE) to characterize the properties of proteins under physiological conditions. The sample was then analyzed, employing nondenaturing isoelectric focusing in the first dimension and sodium dodecyl sulfate (SDS) electrophoresis in the second dimension (Type II 2-DE), to study the dissociation of noncovalently bound protein subunits. In the third type of 2-DE (Type III 2-DE), proteins were separated by nondenaturing isoelectric focusing and treated with urea/mercaptoethanol/SDS and then subjected to second-dimension SDS electrophoresis, to study the dissociation of disulfide-bonded polypeptides. In the fourth type of 2-DE (Type IV 2-DE), the conditions of denaturing 2-DE were employed; the sample was treated with SDS-mercaptoethanol-urea-Nonidet P-40, separated by denaturing isoelectric focusing, and then subjected to SDS electrophoresis. The combined 2-DE technique will be useful to construct a comprehensive database of plasma proteins combining a "nondenaturing protein map" (a protein map) and a "denaturing protein map" (a polypeptide map).

Microsphere embolism-induced elevation of nerve growth factor level and appearance of nerve growth factor immunoreactivity in activated T-lymphocytes in the rat brain

Changes in nerve growth factor (NGF) level and type of cells producing NGF were investigated in the rat brain after sustained cerebral embolism. The NGF level was determined by a two-site enzyme immunoassay specific for NGF. The cerebral cortex, striatum, and hippocampus of the embolized hemisphere maximally contained 2.4-, 2.4-, and 1.7-times higher NGF levels than the corresponding regions of the nonembolized hemisphere. A significant increase was transiently observed for 1 week in the cerebral cortex and striatum, whereas the increase was longer lasting, at least of 4 weeks' duration, in the hippocampus. To examine the localization of NGF-like immunoreactivity (NGF-LI), we used a newly developed anti-NGF peptide antiserum that specifically recognized a 30-kDa molecule(s) in the hippocampal extracts or in NGF cDNA-transfected cells, suggesting that the antibody predominantly reacted with the putative NGF precursor protein(s). NGF-LI, which was localized in neurons of the normal or non-embolized hemisphere, was reduced, and on the embolized side new signals emerged in small non-neuronal cells having a round shape. These included cells with common leukocyte antigen CD45 and T-lymphocyte antigen CD3, which did not appear in the normal or non-embolized hemisphere. NGF-LI and CD3 were colocalized in a substantial number of the cells, suggesting that some activated T-lymphocytes produce NGF for neuronal regeneration after sustained cerebral embolism.

Pretranslational regulation of rhythmic type II iodothyronine deiodinase expression by beta-adrenergic mechanism in the rat pineal gland

It has been demonstrated that type II iodothyronine deiodinase is present in rat pineal gland, and the deiodinase activity markedly increases during the hours of darkness, primarily through beta-adrenergic mechanism. We have studied the relationship between pineal type II iodothyronine deiodinase messenger RNA (mRNA) and the deiodinase activity to elucidate the mechanisms involved in the nocturnal rise in pineal deiodinase activity. Northern analysis has demonstrated that type II iodothyronine deiodinase mRNA is expressed in rat pineal gland, and the mRNA markedly increases during the hours of darkness. The nocturnal increase in pineal type II iodothyronine deiodinase activity is preceded by the increase in its mRNA. Daytime isoproterenol administration resulted in a rapid increase in pineal type II iodothyronine deiodinase mRNA followed by the increase in deiodinase activity. Propranolol treatment, bilateral superior cervical ganglionectomy, or constant light exposure significantly suppressed the nocturnal rise in type II iodothyronine deiodinase mRNA as well as the deiodinase activity. Moreover, isoproterenol or (Bu)2AMP stimulated type II iodothyronine deiodinase mRNA and the deiodinase activity in cultured rat pineal glands. These results suggest that the rhythmic change in pineal type II iodothyronine deiodinase activity is regulated at least in part at the pretranslational level by a beta-adrenergic mechanism transmitted through superior cervical ganglia.

Efficacy of L-846 in patients with insomnia: evaluation by polysomnography

The effects of L-846, an ultra-short-acting pyrazolopyrimidine hypnotic, on sleep were studied in nine insomniacs and two neurotic patients with insomnia. The patients were randomly assigned to receive 5 mg (n=6) or 10 mg (n=5) L-846. The study schedule comprised of one adaptation night, two baseline nights, three drug nights, and two withdrawal nights. Sleep latency and slow wave sleep (SWS) latency was largely shortened and %SWS increased in the early phase of sleep. No clear evidence of rebound insomnia was noted.

Wrist activity rhythm and sleep diary of delayed sleep phase syndrome

Wrist activity rhythm and sleep diary data in a case of delayed sleep phase syndrome were investigated. The sleep self-estimation was nearly compatible with the activity levels of the actigraph. The actigraphic data were also analyzed. The subject's most fixed period of activity was 24.31 h, and acrophase (time of day) that fixed the data to a 24 h period was 03.25 h. The subject has had reversed night and day sleep patterns for more than 7 years. It was very difficult to advance the sleep phase when the delayed phase has been continuous long-term under the state of poor social cues.

Primary culture of cells from hyperfunctioning thyroid adenoma with an activating mutation of G alphas

We analyzed cultured cells from hyperfunctioning thyroid adenoma and its surrounding thyroid tissue from a Japanese woman and determined the nucleotide sequences of genes encoding the alpha subunit of the stimulatory G-protein 1 (G alphas) and thyrotropin (TSH) receptor in its tumor tissue. Primary culture of cells from hyperfunctioning thyroid adenoma and its surrounding thyroid tissue revealed that cAMP production was constitutively activated while intracellular Ca2+ concentration was suppressed both at the basal level and in the response to TSH stimulation in the cells from tumor tissue compared with those from non-tumor tissue. Nucleotide sequence analysis demonstrated the somatic missense mutation at codon 201 (CGT(Arg)-CAT(His)) of G alphas gene in tumor tissue but not in its surrounding tissue. No mutation was observed in the transmembrane region of TSH receptor. These results suggest that cAMP regulatory cascade is constitutively activated while phospholipase C-Ca2+ signaling cascade is suppressed in hyperfunctioning thyroid adenoma with an activating mutation of G alphas gene in the present case.

Treatment of sleep apnea with a new separated type of dental appliance (mandibular advancing positioner)

We investigated a new separated type of dental appliance (mandibular advancing positioner: MAP) that is mobile and allows free adjustment of mandibular advancement. In 8 adult male patients with sleep apnea syndrome (SAS), the mean apnea index (AI) decreased from 31.1 to 4.2, and the mean apnea hypopnea index (AHI) decreased from 44.2 to 11.7. The distance of mandibular advancement using the Flankfort horizontal plane as a standard ranged in the 8 SAS patients from 1.8 to 5.0 mm by lateral cephalograms. A high positive correlation was observed between the distance of mandibular advancement and the rate of improvement in AI (R2 = 0.878), or the rate of AHI (R2 = 0.861), showing a higher improvement rate with more marked mandibular advancement.

[Therapeutic outline of sleep disorders]

The more sleep disorders become chronic, the more they become resistible for the treatments. Therefore, it is most important that physicians establish the good relationship with patients and correctly diagnose and treat patients who have acute or transient sleep complaints. Physicians can improve patients' quality of life by evaluation of disease, supportive psychotherapy which include Morita therapy and behavior therapy, sleep hygine advice, and appropriate medications. In all patients, it is necessary for physicians to be aware of the physical, psychological and pharmacological factors, social aspects, and environmental factors of patients, because all these factors play an important role in appearance of sleep disorders.

The Neuropeptide Cyclo(His-Pro) Levels are Increased in Diabetic Ketoacidosis and Fall with Treatment in Parallel with Levels of Glucagon

The importance of insulin deficiency and glucagon excess is recognized as critical in the pathogenesis of diabetic ketoacidosis (DKA). The finding of elevated levels of another gut peptide in DKA with potential relevant physiological effects might renew discussion of the pathogenesis of this disorder. Cyclo(His-Pro) is a gut-brain peptide found in gut of rat and man. In pancreas it is localized to alpha cells. A stereospecific hepatic bonding site has been found. We have shown that cyclo(His-Pro) augments the insulin response to oral glucose in rat by decreasing hepatic insulin clearance. In view of cyclo(His-Pro)'s location in alpha cells, the hepatic binding site and action described, we wondered if levels of cyclo(His-Pro) might be elevated in a hyperglucagonemic state such as DKA and whether these levels might correlate with those of glucagon and other commonly followed parameters in DKA. Plasma was collected from 7 nondiabetic controls and 9 patients in DKA before and after 4, 8, 12, and 24 h of therapy and assayed for glucose, HCO3, anion gap, glucagon and cyclo(His-Pro). Cyclo(His-Pro) levels were higher in DKA patients before therapy than controls (15.6 ± 3.2 vs. 8.0 ± 0.2 pmol/ml; p =0.023) as were glucagon levels (201 ± 4 vs. 56 ± 5ng/L; p = 0.006). Cyclo(His-Pro) levels fell significantly with treatment (15.6 ± 3.2 vs 8.1 ± 1.1; p = 0.024) and in parallel with those of glucagon. We conclude that cyclo(His-Pro) levels are increased in patients with DKA before therapy and fall in parallel with those of glucagon. This represents the first report of altered levels of this peptide in a disease state.

Northern analysis of type II iodothyronine deiodinase mRNA in rat Harderian gland

It has been known that type II iodothyronine deiodinase activity is present in rat Harderian gland and the activity is significantly increased by isoproterenol administration. We have performed Northern analyses to study whether the transcript for type II iodothyronine deiodinase is expressed in rat Harderian gland and whether the isoproterenol stimulation of type II iodothyronine deiodinase activity in rat Harderian gland is due to the change in its mRNA level. Northern analyses have demonstrated that type II iodothyronine deiodinase mRNA, approximately 7.5 kb in size, is expressed in rat Harderian gland, and the mRNA levels as well as the deiodinase activities are greater in hypothyroid rats than those in euthyroid rats. Type II iodothyronine deiodinase mRNA levels and the deiodinase activities in Harderian gland were increased by isoproterenol administration, and the increase in the mRNA levels preceded that in the deiodinase activities. These results indicate that 7.5 kb transcript for type II iodothyronine deiodinase is expressed in rat Harderian gland and beta-adrenergic stimulation of type II iodothyronine deiodinase activity is due at least in part to the increase in its mRNA level.

Excessive twitch movements in rapid eye movement sleep with daytime sleepiness

A man who showed excessive twitch movement, such as fragmentary myoclonus (FM) and periodic movements in sleep (PMS) predominantly during REM sleep, is reported. He complained of excessive daytime sleepiness (EDS). After examination, his twitch movements were shown not to accompany narcolepsy, and his EDS were considered to originate from nocturnal sleep disturbance caused by FM and PMS.

Expression and nocturnal increase of type II iodothyronine deiodinase mRNA in rat pineal gland

It has been demonstrated that thyroxine deiodinating activity is present in rat pineal gland, and its activity increases significantly during the night time. We have studied whether mRNA for type II iodothyronine deiodinase is expressed in rat pineal gland and whether the nocturnal rise of pineal T4 deiodinating activity is due to the change in type II iodothyronine deiodinase mRNA level. Reverse transcription-polymerase chain reaction amplification and Northern blot analyses have demonstrated that type II iodothyronine deiodinase mRNA is expressed in rat pineal gland and its mRNA level increases markedly at midnight. These results suggest that the nocturnal rise in pineal T4 deiodinating activity is due to the change in type II iodothyronine deiodinase mRNA level.

Diagnostic use of daytime polysomnography versus nocturnal polysomnography in sleep apnea syndrome

The usefulness of daytime polysomnography (DPSG) in the diagnosis of sleep apnea syndrome (SAS) is examined. Diagnostic use was investigated by conducting DPSG of two different time periods (Group M, 11.00-14.00 h, and Group A, 15.00-18.00 h). The subjects were 30 patients (28 men and two women; mean age, 54.0 years). Nocturnal polysomnography (NPSG) and DPSG were investigated by comparing indices of sleep, apnea index (AI) and arterial oxygen saturation (SaO2). There was no significant difference among these indices but there was a significant positive correlation between NPSG and DPSG in all variables related to sleep apnea. Moreover, there was no significant difference in the frequency of each type of apnea between NPSG and DPSG in either group. These findings suggest that DPSG is useful not only in diagnosing SAS but in evaluating its severity.

Discrete characteristics of antibodies raised against thyrotropin receptor-related peptides whose sequences are not conserved in the luteinizing hormone/chorionic gonadotropin receptor

In order to identify the specific regions in the human TSH receptor for TSAb and thyroid stimulation-blocking antibody (TSBAb), we produced rabbit antibodies raised against several peptides of the extracellular domain of the human TSH receptor, where sequences are not conserved in the LH/CG receptor, and measured the TSAb activity and TSBAb activity of those antibodies using Chinese hamster ovary cells expressing human TSH receptors. Only antisera from rabbits that were immunized with a peptide of amino acid 32-56, including the small insertion near the N-terminal end of the extracellular domain, showed apparent TSAb activities and have been shown to be significantly precipitated by IgG of patients with Graves' disease. TSAb activity positively correlated with the antibody titers against the peptide in those rabbits. In contrast, antisera from rabbits immunized with a peptide of amino acid 352-378, including a part of the large insertion near the C-terminal end of the extracellular domain, showed the obvious TSBAb activities. TSBAb activity also positively correlated with the degree of antibody titers against the peptide in those rabbits. Moreover, this peptide was significantly immunoprecipitated by the IgG from hypothyroid patients who had TSBAb, and the immunoprecipitation of this peptide positively correlated with TSBAb activities. These results suggest that the epitope responsible for TSAb is quite different from that for TSBAb in the extracellular domain of the human TSH receptor.

The bioactive peptide cyclo(His-Pro) may be absorbed following ingestion of nutritional supplements that contain it

OBJECTIVE

Food contains a number of peptides with potential bioactivity. We previously found ng/mliter to mcg/mliter quantities of cyclo(His-Pro)-like immunoreactivity in a number of foods and nutritional supplements. A number of activities have been attributed to cyclo(His-Pro) (CHP), including appetite inhibition and inhibition of insulin secretion in vitro. We wondered whether the cyclo(His-Pro)-like immunoreactivity present in nutritional supplements might be absorbed and, if so, whether parameters of insulin secretion would be altered.

METHODS

After performing a pilot study which suggested some common nutritional supplements contain CHP, a follow-up study was done to confirm and expand the findings of the pilot study. Eight fasting volunteers ingested approximately 250 mL of a CHP-containing supplement one day, and then an equienergetic CHP-free supplement the next.

RESULTS

Blood drawn for CHP, insulin, glucose, and C-peptide a number of times on both days revealed that when volunteers ingested CHP-containing supplements, CHP levels at 120 minutes were significantly higher than baseline (7.69 +/- 0.50 pmol/mL vs. 9.18 +/- 0.48 pmol/mL; p = 0.011 in the CHP group and 7.90 +/- 0.85 pmol/mL vs. 7.22 +/- 0.73 pmol/mL, p > 0.3 in the CHP-free group) and significantly higher than levels achieved when they drank CHP-free supplements. Levels of glucose, insulin, and C-peptide were not different in the two groups.

CONCLUSION

CHP in nutritional supplements may be absorbed when ingested orally and does not grossly affect glucose or parameters of insulin secretion.

Sex and age differences in soluble guanylate cyclase activity in human platelets

Soluble guanylate cyclase is a key enzyme of nitric oxide (NO)-related intracellular signal transduction in platelets. In the present study, we investigated the effects of sex and age on the enzyme activity in human platelets. Soluble guanylate cyclase activity was determined by generation of cyclic GMP in platelet cytosol. No significant differences in the basal activity of soluble guanylate cyclase were observed between in men and women, and between in young and old subjects. However, soluble guanylate cyclase activity in response to sodium nitroprusside, an exogenous NO donor, was higher in young men than in young and old women. Furthermore, the enzyme activity was lower in old than in young men, but there were no differences in female platelets between from young and old subjects. The present data suggest that NO-related signal transduction system in the platelet is affected by sex and age, which, to certain extent, contributes to different sensitivity of human platelets.

A paradoxical elevation of brain cyclo(His-Pro) levels in hyperphagic obese Zucker rats

Several studies suggest a role for endogenous cyclo(His-Pro) or CHP in appetite regulation. In the present study, we have examined the regional brain distribution of CHP in hyperphagic obese Zucker rats and their lean littermates. The data show a significant elevation in the levels of CHP in many brain regions, including hypothalamus of the obese rat. Within the hypothalamus, the lateral hypothalamic (LH) nucleus of obese rats had significantly higher levels of CHP when compared to that of the lean littermates. Administration of dehydroepiandrosterone, a steroid hormone known to decrease food intake and body weight gain, to obese rats led to decrease in the levels of CHP in the LH. These data further suggest a role for the endogenous CHP in attenuating food intake.

A novel analog of TRH, YM14673, causes a decrease in brain TRH receptors in vitro

Biochemical mechanisms by which analogs of thyrotropin-releasing hormone (TRH) produce their potent neuropharmacological actions on the brain remain ill-defined. We tested effects of YM14673, a novel analog of TRH, on TRH receptors in rat brains in vitro. No significant binding of [3H]YM14673 to brain plasma membranes occurred. In contrast, preincubation of membranes with YM14673 caused dose-dependent decreases in TRH binding. This was not due to competition for TRH binding sites or existence of metabolites of YM14673. Preincubation with DN1417 (an another TRH analog), cyclo(His-Pro) or methionine-enkephalin did not affect the binding. Affections of YM14673 on TRH binding were observed when cerebral cortical membranes were studied; those were not seen in membranes prepared from hypothalamus, striatum, midbrain, hippocampus, or pons-medulla. The present data indicate that YM14673 exerts its characteristic neuro-pharmacological functions through interacting with TRH binding sites in the brain.

Biology of enterostatin. II. Development of enzyme-linked immunosorbentassay (ELISA) for enterostatin (Val-Pro-Asp-Pro-Arg), the procolipase activation peptide

Enterostatins belong to a family of pentapeptides (e.g., Val-Pro-Asp-Pro-Arg in pig, horse, dog, and rat; Ala-Pro-Gly-Pro-Arg in human and chicken; and Val-Pro-Gly-Pro-Arg in rat) derived from the amino-terminus of procolipase after the action of trypsin. Pharmacologic studies with Val-Pro-Asp-Pro-Arg have suggested a role for this peptide in appetite regulation and pancreatic insulin secretion. Studies into the distribution of enterostatins or the role of endogenous peptides have not been possible due to the lack of a suitable method for enterostatin assay. To this end, we raised a highly specific antibody and developed an enzyme-linked immunosorbent assay for Val-Pro-Asp-Pro-Arg. Using the newly developed assay we have shown the presence of Val-Pro-Asp-Pro-Arg-like immunoreactivity (2455 +/- 440 pmol/g) in the rat brain.

Attenuation of alcohol-induced hypothermia by cyclo (His-Pro) and its analogs

Acute administration of cyclo (His-Pro) to rats cause a dose-dependent decrease in ethanol-induced hypothermia. Bromination of the imidazole moiety of histidine in cyclo (His-Pro) resulted in a significant increase in its potency to attenuate ethanol hypothermia. In contrast, benzylation of the imidazole moiety of histidine or the substitution of one or both of the amino acids in cyclo(His-Pro) led to a total loss of its thermomodulatory activity. In conclusion, it appears from these preliminary data that it may be possible to design analogs of CHP that may be effective antagonists for ethanol hypothermia.

Augmentation of dietary fat preference by chronic, but not acute, hypercorticosteronemia

Numerous studies have documented a role for corticosterone in appetitive behavior, including caloric intake and dietary fat preference. In the present study, we have examined the mechanism(s) underlying modulation of dietary fat preference by corticosterone. The results of these studies show a) an increased fat preference with increased basal urinary output, or decreased stimulation of corticosterone output on fasting, b) elevation of fat preference following chronic, but not acute, hypercorticosteronemia produced by exogenous corticosterone administration, and c) emergence of hypercorticosteronemia prior to the development of increased fat preference in developing rats. These observations have led us to suggest that increased fat preference after chronic hypercorticosteronemia may be secondary to changes in the levels or actions of agents known to affect fat intake.

Effects of acetazolamide on the sleep apnea syndrome and its therapeutic mechanism

Twenty male patients with sleep apnea syndrome were treated with acetazolamide (AZM), a carbonic anhydrase inhibitor. In 14 of the patient a significant decrease was found in the number of apnea, apnea index and % apnea time (percentage of time spent with apnea to the total sleep time) with improvement in sleep structure, clinical symptoms, such as insomnia, daytime excessive sleepiness and snoring. A significant decrease was also observed in arterial blood pH and HCO-3 in the 14 improved patients. On the other hand, no improvement occurred in the parameters of sleep apnea and sleep with AZM in the remaining six patients. Moreover, metabolic acidosis and an improvement in arterial blood gases did not occur with AZM in the six patients.

Identification of cyclo(His-Pro)-like immunoreactivity in human follicular fluid: correlation with steroid and peptide hormones

OBJECTIVE

The purpose of this study was to evaluate human follicular fluid (FF) for the presence of cyclo(His-Pro)-like immunoreactivity (CHP-LI). After verifying its presence, we quantitated the levels and investigated correlations with other follicular parameters, including hormone levels.

METHODS

Follicular fluid was collected from female volunteers undergoing controlled ovarian hyperstimulation. Fluid was collected by follicular puncture, either transvaginally (in vitro fertilization) or laparoscopically (gamete intrafallopian transfer) at the time of oocyte retrieval (N = 137). Follicular size was determined ultrasonographically. Assays for steroid and peptide hormones were determined with commercially available radioimmunoassay kits. CHP-LI was measured using a previously reported assay; parallel dilution curves and column chromatography aided in immunoidentity.

RESULTS

The mean FF CHP-LI concentration (13.10 +/- 1.83 nmol/L, N = 137) was greater than the corresponding serum values (9.42 +/- 2.45 nmol/L; N = 21) (P < .05). Large follicles (20 mm or greater; 14.45 +/- 1.74 nmol/L) contained significantly more CHP-LI than either medium follicles (16-19 mm; 11.51 +/- 1.88 nmol/L) or small follicles (15 mm or smaller; 10.83 +/- 2.12 nmol/L) (P < .05). Positive correlations were found between FF CHP-LI values and corresponding FF progesterone and prolactin concentrations (r = 0.67 and 0.62, respectively; P < .05).

CONCLUSION

Mean CHP-LI levels in the FF are greater than those in the corresponding serum. We suggest that the neuropeptide may be originating from either peptidase cleavage of precursor peptides or from granulosa cell production.

Does cyclo(His-Pro) act like amphetamine?

In many pharmacologic tests, cyclo(His-Pro) (CHP) appears to act like a dopaminergic agonist and augments the actions of amphetamine (AMP). Therefore, to determine whether CHP is an AMP-like peptide, a comparison between CHP and AMP was made using four separate tests known to be AMP-responsive. These include, food intake, locomotor activity, dopamine uptake and modulation of binding sites for amphetamine and mazindol. A decrease in food intake and increase in spontaneous locomotor activity and stereotypy was observed after peripheral administration of amphetamine but not CHP. Chronic CHP administration resulted into a decrease in striatal amphetamine - and increase in mazindol-binding sites; in contrast, chronic amphetamine decreased both amphetamine - and mazindol-binding sites. These results show a clear dissociation between CHP and AMP suggesting that CHP is not an amphetamine-like peptide.

Role of endogenous cyclo(His-Pro) in cold-induced hypothermia in the desert rat (Mastomys natalensis)

Central administration of exogenous cyclo(His-Pro) (CHP) is known to produce hypothermia in rodents. In the present study, we examined the role of endogenous CHP in cold-induced hypothermia in the desert rat, Mastomys natalensis. The results of these studies show that a rise in hypothalamic CHP content accompanied a decrease in rectal temperature during cold exposure. Immunoneutralization of endogenous CHP resulted in a significant decline in cold-induced hypothermia. In addition, central administration of cyclo(Ala-Gly), a structural analogue of CHP, also led to a decrease in cold-induced hypothermia. The results of these studies show that changes in endogenous CHP levels may affect body temperature regulation.

Corticosterone facilitation of inhibition of fat intake by enterostatin (Val-Pro-Asp-Pro-Arg)

Enterostatin or Val-Pro-Asp-Pro-Arg (VPDPR) is the amino-terminal pentapeptide of procolipase; VPDPR is generated during tryptic activation of procolipase to lipase. In rodents, exogenous VPDPR has been shown to cause a selective decrement in fat appetite. To understand the mechanism(s) underlying the action of this peptide, we have studied the effects of corticosterone, an adrenal hormone known to modulate caloric intake, on VPDPR-mediated inhibition of appetite. The results of this study show a significant increase in the inhibition of total caloric intake by 250 micrograms/kg VPDPR following corticosterone treatment (control, 2.3%; corticosterone treated, 22.7%). Furthermore, the decrement in the caloric intake in corticosterone-treated rats was exclusively due to the loss of fat intake.

Individual differences in the macronutrient preference profile of outbred rats: implications for nutritional, metabolic, and pharmacologic studies

While screening outbred male Holtzman Sprague-Dawley rats for their macronutrient (protein, carbohydrate, and fat) preferences, we noticed substantial group-to-group variation in the preference profile. This led us to analyze preference data on two hundred and seventy rats collected over a three-year period to determine whether preferences could be predicted. The results led us to conclude that observed variations in macronutrient preference profiles may be secondary to genetic heterogeneity in the outbred population. We have also shown that the outcome of the pharmacologic effects of two agents (insulin and enterostatin) on appetitive behavior will vary from animal to animal within a single group. Accordingly, researchers must be aware that the breeding history of the laboratory animal is a major factor in the outcome of the experiment and interpretation of the findings.

Identification of inositol 1,4,5-trisphosphate binding in human pheochromocytoma

An attempt was made to identify a specific binding of inositol 1,4,5-trisphosphate (IP3) to human chromaffin cell tumors. Crude microsomal fractions of pheochromocytomas possessed significant binding sites for [3H]IP3 with high- and low-affinity constants (Kd = 5.46 and 538 nM, respectively). The binding to these sites was rapid, saturable (reached equilibrium by 1 min at 0 degrees C) and reversible. Competition studies with other inositol phosphate analogs indicated the stereotypic specific binding for IP3. Although no significant difference was observed in the binding densities of IP3 between pheochromocytomas and adrenal nonfunctioning adenomas, the values of high-affinity constants were significantly lower in the former than the latter group (5.77 +/- 1.07, n = 5 vs. 11.30 +/- 1.98 nM, n = 4, p less than 0.05). The present data indicate that characteristics of IP3 binding sites are congruous with their receptor functions and that changes in its binding sites may contribute to the biochemical dissimilitudes in pheochromocytomas.

Inhibitory effects of okadaic acid on thyrotropin and prolactin secretion from rat anterior pituitaries

The present study was undertaken to elucidate the effects of okadaic acid, a potent inhibitor of protein phosphatases, on thyrotropin (TSH) and prolactin (PRL) secretion, and on the hydrolysis of inositol phospholipids in rat anterior pituitaries. Preincubation of anterior pituitaries with okadaic acid caused a dose dependent decrease in TRH- and K(+)-induced TSH secretion, whereas basal secretion of TSH was not affected by pretreatment with okadaic acid. In contrast, okadaic acid resulted in a marked inhibition in both basal, and TRH- and K(+)-stimulated PRL release from anterior pituitaries. In addition, pretreatment with okadaic acid caused a slight, but significant decrease in the formation of [3H]inositol phosphate ([3H]IP) in rat anterior pituitaries. The present study suggests that okadaic acid blocks the release of TSH and PRL by inhibiting Ca2+ influx and that inhibitory effects of okadaic acid on PRL release are, at least in part, due to the inhibition of inositol phospholipid hydrolysis.