Oral glucose ingestion stimulates cholecystokinin release in normal subjects and patients with non-insulin-dependent diabetes mellitus

The role of glucose in the regulation of plasma cholecystokinin (CCK) level was investigated in healthy control subjects and patients with non-insulin-dependent diabetes mellitus (NIDDM). Plasma CCK concentration was determined by a specific and sensitive bioassay and by a highly sensitive and reliable double-antibody radioimmunoassay using OAL-656 as an antiserum. In control subjects, ingestion of Trelan G-75 (1,200 mOsm/L,225 mL), which is equivalent to 75 g glucose as metabolic products, caused a rapid and significant increase in plasma CCK bioactivity from 1.3 +/- 0.2 to a peak of 5.8 +/- 0.6 pmol/L and immunoreactive CCK concentration from 1.2 +/- 0.1 to 4.6 +/- 0.6 pmol/L. Ingestion of 75 g glucose in 225 mL water (33.3% solution) increased plasma CCK bioactivity to a similar degree to that observed following Trelan G-75 (peak response, 4.5 +/- 0.4 pmol/L). The same volume of 0.9% NaCl solution or water failed to increase plasma CCK concentration. A smaller dose of glucose (50 b/150 mL water) increased plasma CCK concentration, although the peak level (3.0 +/- 0.5 pmol/L) was less than that observed following 75 g glucose. In patients with NIDDM, Trelan G-75 ingestion increased CCK concentration, but the peak level was lower, albeit insignificantly, than that of normal subjects. When the maximal increment of plasma CCK above the basal value was compared between control and NIDDM subjects, the differences were statistically significant (NIDDM, 3.6 +/- 0.1 pmol/L; control, 5.0 +/- 0.4; P < .01). However, integrated CCK responses to Trelan G-75 in NIDDM (165.8 +/- 15.5 pmol/120 min) were not significantly different from those in control subjects (189.8 +/- 15.9 pmol/120 min). Peak CCK bioactivity occurred within 10 to 30 minutes of ingestion, preceding the increase in glucose and insulin. These results suggest a possible effect of CCK on insulin release in humans, and that the CCK secretory response to glucose in well-controlled diabetic patients is not significantly altered.

Changes of GTP binding proteins, not neurofilament-associated proteins, in the brain of the neurofilament-deficient quail, "Quiver"

A neurofilament (NF)-deficient mutant of the Japanese quail was named "Quiver", as it showed generalized quivering as a clinical sign. NF consists of three major subunits; low, middle and high. We previously reported that the noradrenaline and 5-hydroxytryptamine content in the neostriatum of the Quiver's brain was different from that in the normal quail, although disappearance of the three NF proteins occurred in all areas of the Quiver's brain. Thus, NF-related proteins may show considerable changes in the specific sites of Quiver's brain. In this study, an examination was made of the changes in NF-related proteins in the Quiver, by immunoblotting analysis. The amounts of cyclin-dependent kinase 5 (cdk5), which phosphorylates NF proteins, and tau which is a substrate of cdk5, in the neostriatum of the Quiver, were essentially the same as those in the normal quail, although NF proteins could not be detected in the Quiver. The amount of alpha-tubulin in the Quiver's brain was similar to that in the normal quail. Next, we investigated the changes of GTP binding (G) proteins in the Quiver's brain, because cytoskeletal components such as tubulin and F-actin bind with G proteins. [32P]ADP-ribosylation of G proteins (Gs by cholera toxin and Gi/G0 by pertussis toxin) in the neostriatum of the Quiver increased significantly, although alpha subunits of G proteins showed no change by immunoblotting analysis. The ratios of the trimer form in G proteins thus appear to increase more in the NF-deficient Quiver brain than in the brain of the normal quail. The G proteins-mediated adenylate cyclase activities were the same in the brain of both the Quiver and the normal quail. Possible interactions between NFs and G proteins are discussed.

Multiple myeloma-associated systemic vasculopathy due to crystalglobulin or polyarteritis nodosa

Systemic vasculopathy is a rare complication of multiple myeloma (MM). We describe a patient diagnosed with MM who developed clinical features of systemic vasculopathy including gangrene, livedo reticularis, hypertension, renal failure, and perforation of the small intestine. Histopathologic examination of the small intestine revealed necrotizing vasculitis in the small arteries, along with crystalline deposits in the small vessels. To our knowledge, previously reported cases of systemic vasculopathy associated with MM include at least 9 cases due to crystalglobulin deposition in vessels and 2 due to polyarteritis nodosa. Deposits of crystalglobulin may have induced systemic necrotizing vasculitis in our patient.

Effect of brief hypoxia on reperfusion arrhythmias and release of Ca2+ by rat heart homogenate blocked by ryanodine

OBJECTIVES

We previously reported that a brief period of hypoxic perfusion (BHP) prior to ischemia in rat hearts improved functional recovery upon reperfusion with reduced Ca2+ overload. The present study was designed to determine whether the effect of BHP would be associated with a reduction in reperfusion arrhythmias and a preservation of function of the sarcoplasmic reticulum (SR).

METHODS

Hearts were subjected to 40 min of global ischemia and 30 min of reperfusion after a 20 min period of oxygenated perfusion (oxygenated group: OG), or a 10 min period of oxygenation and 10 min of hypoxic perfusion (hypoxic group: HG). We evaluated the release of Ca2+ by SR blocked by ryanodine, the recovery of left ventricular function, and the reperfusion induced ventricular tachycardia/fibrillation (VT/VF).

RESULTS

Functional recovery improved and the incidence and duration of reperfusion VT/VF were reduced in HG. In HG the uptake of Ca2+ in SR decreased during ischemia, but this decrease was less than that in OG. However, recovery of Ca2+ uptake after reperfusion did not differ between groups. The release of Ca2+ by SR blocked by ryanodine was inhibited in HG throughout the ischemia-reperfusion sequence.

CONCLUSIONS

Observations suggest that the benefits of BHP on recovery of function and reperfusion arrhythmias were associated with a decrease in release of Ca2+ by SR blocked by ryanodine.

Two isoforms of the prostaglandin E receptor EP3 subtype different in agonist-independent constitutive activity

We previously identified two isoforms of the mouse prostaglandin E receptor EP3 subtype, EP3 alpha and EP3 beta, with different carboxyl-terminal tails, produced through alternative splicing and showing different efficiency in inhibition of adenylate cyclase (Sugimoto, Y., Negishi, M., Hayashi, Y., Namba, T., Honda, A., Watabe, A., Hirata, M., Narumiya, S., and Ichikawa, A. (1993) J. Biol. Chem. 268, 2712-2718). To assess the role of the carboxyl-terminal tails in the G protein coupling properties of the EP3 receptor, we examined the Gi activities of EP3 alpha, EP3 beta, and the mutant receptor, in which the carboxyl-terminal tail was truncated at the splicing site. The EP3 alpha receptor showed marked agonist-independent constitutive inhibition of adenylate cyclase, while EP3 beta receptor had no agonist-independent inhibition. On the other hand, the truncated receptor showed only agonist-independent constitutive inhibition. The constitutive activity of these receptors on the stimulation of GTPase activity of Gi was also observed. Thus, alternative splicing produced two isoforms with different carboxyl-terminal tails and with different constitutive activity, and the truncation of the carboxyl-terminal tail caused full constitutive activity.

Antigenic analysis of Japanese encephalitis viruses in Asia by using monoclonal antibodies

Based on our previous study using monoclonal antibodies against three Japanese encephalitis (JE) virus strains, Nakayama-RFVL, Beijing 1 and Kamiyama, 25 JE virus strains isolated mainly in Japan and some from Southeast Asia between 1935 and 1979 fell into five antigenic groups, Nakayama, Beijing 1, Kamiyama, Muar and 691004. In the present study, monoclonal antibodies against Muar and 691004 strains were produced to analyze immunological characteristics of JE virus in detail. We obtained the Muar group-specific antibody and three anti-691004 monoclonal antibodies which showed different reactivities. Furthermore, antigenic comparison of the 22 JE virus strains isolated in Asia between 1963 and 1984 was performed by using the 15 monoclonal antibodies characterized by the different reactivities against the above five antigenic groups. Of these 22 strains, the 17 strains reacted with the Kamiyama group-specific monoclonal antibody, but anti-Nakayama, anti-Beijing 1 and anti-Muar group-specific monoclonal antibodies showed no reactivities with any of the strains. This suggested that the currently prevalent JE virus strains in Asia belonged to the Kamiyama group. The other five strains, ThCMP 1982, KE083, KE093, 733913 and Ling, did not react with the above four group-specific monoclonal antibodies, but all except the KE093 strain showed a similar pattern to the Kamiyama strain on the basis of the reactivities against the other 11 antibodies. The KE093 strain isolated from Thailand in 1983 showed immunologically outstanding difference from other strains.

Two cases of duodenal gangliocytic paraganglioma: immunocytochemical characteristics

Two cases of duodenal gangliocytic paraganglioma were studied by means of immunocytochemical methods using 41 kinds of antibodies. The tumors consisted of three histological types; carcinoid, ganglioneuroma and paraganglioma. Tumors of both cases exhibited immunoreactivity to at least one or as many as three of the following: calcitonin, calcitonin-gene related peptide, endocrine granule constituent, Leu7, neuropeptide Y and basic fibroblast growth factor. In addition, these tumors were also immunopositive for neuron specific enolase, S-100 protein, neurofilament protein, pancreatic polypeptide, chromogranin A, somatostatin, leuenkephalin, substance P and vasoactive intestinal peptide, as has been described in previous reports. In one case, tumor cells were immunopositive for adrenocorticotropin, bombesin, gastrin releasing peptide, myelin basic protein, neuroendocrine marker and tyrosine hydroxylase. Moreover, paraganglioma cells of tumors showed both argyrophilia and argentaffinity. These results suggest that duodenal gangliocytic paraganglioma may originate from embryonic neuroinsular complex.

Structure and function of kidney water channels

There is now firm evidence that water transporting proteins are expressed in renal and extrarenal tissues. In the kidney, proximal-type (CHIP28) and collecting duct (WCH-CD) water channels have been identified. We have cloned three kidney cDNAs with homology to the water channel (aquaporin) family, including a mercurial-insensitive water channel (MIWC), and a glycerol-transporting protein (GLIP) in collecting duct basolateral membrane. To elucidate water transporting mechanisms, a series of molecular and spectroscopic studies were carried out on purified CHIP28 protein and expressed chimeric and mutated CHIP28 cDNAs. The results indicate that CHIP28 transports water selectively, that CHIP28 monomers are assembled in membranes as tetramers, but that individual monomers function independently. Monomers contain multiple membrane-spanning helical domains. Based on these data and recent electron crystallography results, a model for water transport is proposed in which water moves through narrow pores located within individual CHIP28 monomers.

Reversal of daunomycin and vinblastine resistance in multidrug-resistant P388 leukemia in vitro through enhanced cytotoxicity by triterpenoids

Examined in vitro were the effects of some triterpenoids from Panax (Araliaceae) and Glycyrrhiza (Leguminosae) spp. on the sensitivity to daunomycin (DAU) and vinblastine (VBL) of adriamycin (ADM)-resistant P388 leukemia cells (P388/ADM), which were resistant to multiple anticancer drugs. Quasipanaxatriol, 20(S)-protopanaxatriol, ginsenoside Rh2, and compound K greatly enhanced the cytotoxicity of the anti-cancer drugs in P388/ADM cells. The extent of enhancement was different among the triterpene compounds; the 4- to 46-fold increase in DAU cytotoxicity was observed in P388/ADM cells in the presence of non-toxic or marginally toxic concentrations of individual compounds, while those for VBL were in the ratios of 2- to 37-fold. The maximum increase in cytotoxicity was observed with 50 microM quasipanaxatriol; the resistance indices defined to be the ratios of the IC50 values for P388/ADM and P388 parental cells decreased from 79 to 1.7 and from 180 to 4.9 in the cases of DAU and VBL, respectively. The reversal of DAU resistance in P388/ADM by quasipanaxatriol could be explained by the effective accumulation of the drugs mediated by the DAU-efflux blockage.

Functional reconstruction of a bilateral maxillectomy defect using a fibula osteocutaneous flap with osseointegrated implants

We have achieved functional reconstruction for a bilateral upper alveolar bone, gingival, and palatal defect that has various problems originating from instability of the prosthesis using the fibula osteocutaneous flap with osseointegrated implants. The flap had three bone segments and two skin paddles. The combined bone segments created the upper alveolar arch, and the skin paddles closed the palatal defect. Nine months later, prosthodontic treatment was performed successfully. Our procedure restored the patient to masticatory function of the upper jaw, intelligible speech, and natural facial appearance. As a result, quality of life of the patient was extremely improved.

Pancreatic enzyme activity after a pylorus-preserving pancreaticoduodenectomy reconstructed with pancreaticogastrostomy

This study was initiated to clarify whether the main hydrolytic enzymes of the pancreas are activated or inactivated when secreted into the stomach of patients who had undergone a pylorus-preserving pancreaticoduodenectomy (PPPD) and were given a pancreaticogastrostomy (PG) for the reconstruction. Seventeen such patients, 15 cancer patients and two pancreatic patients, who underwent PPPD-PG reconstruction were postoperatively followed up for 3 or more years to investigate the influence of the gastric acid on the p-type amylase and lipase activity. Results revealed that when the pH was < 3.0, both the p-type amylase and the lipase secretion remained inactivated, but when the pH was > 3.1, the activity of both enzymes increased proportionately. The pancreatic enzyme activity in the small intestine was also investigated in seven patients, six cancer cases and one case of pancreatitis, given a PPPD-PG reconstruction, and it was found that the pancreatic enzyme activity in the small intestine increased after milk loading. Further, the fecal pancreatic enzyme activity was investigated in 17 patients given a PPPD-PG reconstruction. Results reveal that the fecal p-type amylase, lipase, and chymotrypsin activity amounted to 21, 27, and 31% of the respective values seen in 10 healthy volunteers. However, the fecal pancreatic enzyme activity levels did not differ significantly from the levels seen in 20 pancreaticoduodenectomy patients given a pancreaticojejunostomy reconstruction. In conclusion, it was found that the main hydrolytic enzymes of the pancreas are activated when the gastric acidity is over pH 3.1, which normally occurs after ingestion of a meal.

Relationship between coronary angioscopic and intravascular ultrasound imaging and restenosis

In order to investigate the relationship between restenosis and the morphology detected by coronary angioscopy (CASC) and introvascular ultrasound imaging (IVUS), 17 patients were detected by CASC and IVUS immediately and 3 months after percutaneous transluminal coronary angioscopy (PTCA). The results showed that the dilation index by IVUS (DIu) was significantly lower in restenosis patients than in non-restenosis patients (0.42 +/- 0.08 versus 0.78 +/- 0.16, P < 0.01) and that the elastic recoil (ER) was higher in restenosis patients than in non-restenosis patients (4.51 +/- 1.42 mm2 versus 1.63 +/- 1.20 mm2, P < 0.01), and that the elastic recoil rate (ERR) was also higher in restenosis patients than in non-restenosis patients (57.3 +/- 8.07% versus 21.80 +/- 16.84% P < 0.01), and that coronary dissection, atheromatous plaque and calcification as well as the colour of inner coronary artery had no relation with chronic restenosis. In conclusion, the elastic recoil is one of the important factors of chronic restenosis after PTCA.

Possible function of SP-22, a substrate of mitochondrial ATP-dependent protease, as a radical scavenger

SP-22 was found to be a substrate protein of a mitochondrial ATP-dependent protease in bovine adrenal cortex. Its amino acid sequence was homologous to that of some prokaryotic and eukaryotic proteins such as thioredoxin peroxidase (formerly called thiol-specific antioxidant) in yeast and mammalian brains and the C22 component of alkyl hydroperoxide reductase in Salmonella typhimurium. In the present study, we found SP-22 to have the ability to scavenge reactive oxygen species, thus protecting radical-sensitive proteins such as tryptophan hydroxylase, glutamine synthetase and hemoglobin from oxidation. The protecting activity was enhanced by the addition of horse serum. The "serum factor(s)" seemed to be protein(s), since the physiological roles of SP-22 in adrenocortical mitochondria are discussed.

[An unusual case of peroneal muscular atrophy with rigidity, polyneuropathy, mental retardation, and diabetes mellitus developed in familial Parkinson's disease]

Familial polyneuropathy mimicking Charcot-Marie-Tooth disease associated with parkinsonism and dementia has been reported in literature. We present with similar peroneal muscular atrophy, rigidity of upper extremities, severe peripheral neuropathy, mental retardation and diabetes mellitus. The patient, a 42-year-old man, developed progressive muscle weakness, mental retardation and difficulty in walking in childhood. Because of his pes cavus, he had three surgical operations. At the age of 20 years, he developed distal muscular atrophy of lower limbs. On neurological examination, all limb muscles were atrophic, especially in lower one third of the thigh. Rigidity was noted in the upper extremities. Deep tendon reflexes were hyperactive in the upper and diminished in the lower extremities. Muscle CT revealed low density areas in all the muscles examined, specially in the gastrocnemius and anterior tibial muscles. Needle EMG showed neurogenic change in the forearm, but not in the lower limbs, because of no voluntary contractions obtained due to severe muscle atrophy. Marked slowing of motor conduction velocity with muscle action potentials of very low amplitude was found in the ulnar nerve. Muscle action potentials were not elicited in the median and peroneal nerves. Sensory action potentials were not elicited from the median, ulnar and sural nerves. These findings were consistent with axonal polyneuropathy. In the sural nerve biopsy, the densities of myelinated fibers were markedly decreased. However, unmyelinated fiber densities were relatively preserved. Onion bulb formation was not found. This patient may be classified into hereditary motor-sensory neuropathy (HMSN) type II based on the clinical findings delayed nerve conduction velocities and axonal degeneration in the sural nerve. He has also diabetes mellitus. CT of the brain revealed nothing particular. He is one of members with familial Parkinson's disease (PD) developed in Sagamihara. Peroneal muscular atrophies are not necessarily associated with PD, though it has been occasionally complicated in various neuro-degenerative diseases including parkinsonism. We are now following the patient to detect the symptom of Parkinson's disease for early treatment.

Vesicular monoamine uptake by digitonin-permeabilized PC12 cells: inhibitory effect of neuromodulators and drugs on the amine transport

Vesicular amine transport is crucial for activity of monoaminergic neurons since translocation of cytosolic amine to storage vesicles is required for both exocytotic release and reuptake of the neurotransmitter. We developed a convenient assay system for vesicular amine transport based on permeabilizing the plasma membrane of pheochromocytoma PC12 cells with digitonin at concentrations of 100 to 150 microM. Serotonin (5HT) is a better substrate than either epinephrine or norepinephrine in this assay system. In the presence of 2 mM ATP, 5HT uptake by the permeabilized cells increased linearly for at least 30 min at 25 degrees C, whereas without addition of exogenous ATP, 5HT uptake reached an apparent plateau after 20 min incubation. Reserpine (500 nM) completely blocked the ATP-dependent 5HT uptake in this system whereas nomifensine (10 microM) had no effect, indicating specificity for vesicular transport. Treatment of intact PC12 cells with AMP dose-dependently decreased 5HT uptake with an EC50 of 20-30 microM as measured after cell permeabilization. Treatment of the intact PC12 cells with forskolin and phorbol 12-myristate 13-acetate prior to permeabilization also down-regulated vesicular 5HT transport, whereas the addition of either of these agents into the reaction mixture for the amine uptake by already permeabilized cells did not alter the vesicular uptake activity. Thus, the system can be applied to studies on regulation of the vesicular amine transport by physiological signaling molecules, intracellular messengers, and drugs.

Ameliorative effects of tea catechins on active oxygen-related nerve cell injuries

Active oxygen species are suggested to be concerned with various senile disorders. Tea catechins, (+)catechin (CA), (-)epicatechin (EC) and (-)epigallocatechin gallate, are polyhydroxy-fravan derivatives from tea leaves and have been proposed to possess active oxygen scavenging effect. Tea catechins protected the cultured newborn-mouse cerebral nerve cells from death induced by glucose oxidase. The protective potency of (-)epigallocatechin gallate was weaker than those of EC and CA. Learning ability of mice was assessed by a step-down-type passive avoidance test, and memory impairment of mice was achieved by intracisternal injection of glucose oxidase or cerebral ischemia induced by 10 min occlusion of the common carotid arteries. Intracisternal injection of EC improved the memory impairment induced by intracisternal glucose oxidase, and i.v. injection of CA or EC improved that induced by the cerebral ischemia. CA and EC depressed carrageenin-induced edema in rat hind paw, but (-)epigallocatechin gallate did not. These results suggest that tea catechins ameliorate the injuries or impairments induced by active oxygens through scavenging intracellular active oxygens, and might become useful for protecting human from senile disorders such as dementia.

Effects of protein kinase inhibitors and protein phosphatase inhibitors on cyclic AMP-dependent down-regulation of vesicular monoamine transport in pheochromocytoma PC12 cells

Cyclic AMP down-regulates vesicular monoamine transport in PC12 cells and thereby decreased catecholamine reuptake from the extracellular fluid. We examined the effects of protein kinase inhibitors and protein phosphatase inhibitors on this cAMP action. Treatment of cells with a protein kinase inhibitor, K252a, increased vesicular amine transport and cellular amine uptake, thereby antagonizing the regulatory action of cAMP. In contrast, a protein phosphatase inhibitor, okadaic acid, had the opposite effect on the amine transport, i.e. it enhanced the cAMP action. These results suggest the involvement of a protein phosphorylation process in the cAMP-dependent modulation of vesicular monoamine transport.

Rapid turnover of tryptophan hydroxylase in serotonin producing cells: demonstration of ATP-dependent proteolytic degradation

A rapid and continuous proteolysis of tryptophan hydroxylase was demonstrated with two mast cell lines derived from rat basophilic leukemia cells (RBL2H3) and mouse mastocytoma (FMA3). Under conditions in which protein biosynthesis was arrested by administration of cycloheximide, the decay profile of tryptophan hydroxylase protein was traced by Western blot analysis. Incorporation of [35S]methionine and the chase experiment performed without interfering with the metabolic stage also showed that tryptophan hydroxylase had been cleaved rapidly. The half life of the enzyme was 11-15 min in RBL2H3 cells and 40-60 min in FMA3 cells, and the process was demonstrated to be dependent on intracellular ATP.

[123I-beta-methyl-iodophenyl-pentadecanoic acid myocardial scintigraphy in diabetic patients without overt ischemic heart disease]

Fatty acid metabolism in the myocardium is affected by metabolic disorders such as diabetes mellitus. We evaluated 123I-beta-methyl-iodophenyl-pentadecanoic acid (BMIPP) myocardial scintigraphy in 15 diabetes mellitus patients without overt coronary heart disease. Patients with overt coronary heart disease were excluded by careful history taking, resting electrocardiography, treadmill exercise testing, echocardiography and resting 201Tl scintigraphy. Patients with remarkably impaired left ventricular (LV) systolic function (%FS < 30%) were also excluded. BMIPP uptake scores as the ratio of heart/mediastinum (H/M) and liver/mediastinum (L/M) at 20 minutes after injection were analyzed and compared with clinical profile, serum parameters, and LV parameters obtained from echocardiography. Five of the 15 patients showed abnormal BMIPP images; two patients showed a decreased uptake in the inferior segments, while three showed a diffuse decrease in BMIPP uptake. Body mass index (BMI), fasting blood sugar (FBS), HbAlc, IRI, and LV end-diastolic diameter (LVEDD) were higher in these five patients with abnormal BMIPP findings (abnormal BMIPP group vs normal BMIPP group, BMI: 29 vs 23 kg/m2, p < 0.05; FBS: 178 vs 114 mg/dl, p < 0.01; HbAlc: 7.6 vs 6.2%, p < 0.01; IRI: 18.5 vs 9.5 microU/ml, p < 0.01; LVEDD: 52 vs 44 mm, p < 0.05). 123I-metaiodobenzyl-guanidine (MIBG) scintigraphy in the five patients with abnormal BMIPP uptake showed more severe defects than in the 10 patients with normal BMIPP imaging. BMIPP scintigraphy demonstrated a significant correlation between H/M and L/M by BMIPP (r = 0.74, p < 0.01). Furthermore, correlation between H/M by BMIPP scintigraphy and clinical parameters (BMI, systolic blood pressure, FBS, HbAlc, IRI) were found, suggesting that diabetes mellitus patients without over coronary heart disease show abnormal BMIPP imaging when their general glucose utility and 123I-MIBG uptake are severely impaired (progression of insulin resistance and sympathetic nerve involvement). BMIPP scintigraphy may be useful in investigating the pathogenesis and subclinical abnormality of diabetic heart.