Effects of sigma ligands on the cloned mu-, delta- and kappa-opioid receptors co-expressed with G-protein-activated K+ (GIRK) channel in Xenopus oocytes

1. Taking advantage of the functional coupling of the opioid receptors with the G-protein-activated K+ (GIRK) channel, we investigated the effects of sigma (sigma) ligands of various structural and pharmacological classes, (+)-N-allylnormetazocine ((+)-SKF10047) and (+)-cyclazocine, (+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine ((+)-3PPP), 1,3-di-(2-tolyl)guanidine (DTG), carbetapentane and haloperidol, on the inward K+ current responses in Xenopus oocytes co-injected with each of the cloned mu-, delta- and kappa-opioid receptor mRNAs and the GIRK1 mRNA. 2. (+)-SKF10047 acted as a delta- and kappa-agonist (EC50 values (microM) = 0.618 and 0.652, respectively) and mu-antagonist (IC50 value (microM) = 8.51). (+)-Cyclazocine acted as a kappa-agonist and mu-antagonist (IC50 = 33.2). (+)-3PPP acted as a kappa-agonist (EC50 = 18.08 and a mu-antagonist. DTG acted as a mu- and kappa-agonist (EC50 = more than 30 and 14.88, respectively). Carbetapentane acted as a kappa-agonist and mu-antagonist (IC50 = 11.2). Haloperidol acted as a mu- and delta-agonist (EC50 = 5.683 and 7.389, respectively). 3. All currents induced by sigma ligands were reduced by 1 microM naloxone, an opioid receptor antagonist, and blocked by 300 microM Ba2+, a GIRK channel blocker. It was also indicated that the antagonism by naloxone at the delta-- and kappa-opioid receptors was weaker than that of naloxone at the mu-opioid receptor. The sigma ligands tested had no effect on the current responses in the oocytes injected with each of the opioid receptor mRNAs alone or with the GIRK1 mRNA alone. 4. We conclude that various sigma ligands directly interact with the cloned mu-, delta- and kappa-opioid receptors in Xenopus oocytes. Our results suggest that the effects of the sigma ligands may be partly mediated by the opioid receptors.

[Congenital cholesteatomas in Japanese--forty from our experience and fifty-five from a survey of the Japanese literature]

To determine the locations of congenital cholesteatomas and to elucidate the relationship between ossicular anomalies and congenital cholesteatomas, cholesteatomas from our patients and those reported in the Japanese literature were investigated. We analyzed 40 ears with congenital cholesteatomas (38 patients) experienced by us during the past 9 years. Our criteria of congenital cholesteatoma were as follows: 1. The tympanic membrane manifests neither retraction, perforation, nor granulation, 2. There is no continuity between the tympanic membrane and the matrix of a cholesteatoma. Twenty patients with past histories of otitis media were included. Thirty-three patients (87%) were males and 2 had bilateral congenital cholesteatomas. The ages of the patients ranged from 2 to 46 years (mean: 10.7). A survey of the Japanese literature revealed 55 additional cases of congenital cholesteatoma reported by others.

Beta-cell loss and glucose induced signalling defects in diabetes mellitus caused by mitochondrial tRNALeu(UUR) gene mutation

Japanese diabetic patients with diabetic mothers were screened, using peripheral leukocytes, for an A to G transition at nucleotide pair 3243, a tRNALeu(UUR) mutation of the mitochondrial gene. This mutation was identified in four pedigrees from among 300 unrelated patients. Diabetes mellitus cosegregated with the mutation, except in one young subject, and was maternally inherited. Long-term follow-up revealed that the underlying disorder, in affected individuals, is a progressive impairment of insulin secretion. In accordance with this finding, the mutation was found to be highly prevalent in a diabetes mellitus subset termed slowly progressive IDDM; the mutation was identified in 3 out of 27 subjects enrolled in the prospective study of islet cell antibody (ICA)-positive, initially non-insulin-dependent diabetic Japanese patients, who are at high risk of progressing to insulin dependence over several years. The histologic characteristics of slowly progressive insulin-dependent diabetes mellitus include substantial loss, though incomplete, of pancreatic beta-cells. Mitochondrial gene defects in beta-cells could therefore cause glucose-induced signalling defects as well as beta-cell loss. This would explain the wide range of diabetic phenotypes, from NIDDM to IDDM, in patients with this mitochondrial gene mutation.

Responsiveness of rat nonparenchymal liver cells and spleen cells to the decomposition of erythrocytes exposed to di-n-butyl phthalate and its metabolite

We have reported that di-n-butyl phthalate (DBP) caused the depletion of circulating iron, characterized by the release of iron from both haemoglobin (Hb) and transferrin (Tf). The present study investigated whether the erythrocytes from DBP-treated rats were destroyed by nonparenchymal liver cells (NPC, including Kupffer cells) or spleen cells (SC). In the in vivo study, there were observed depletions of Hb in the blood and of iron in the hepatic Tf fraction, as well as an accumulation of iron in the hepatic hemosiderin (Hs) and splenic Tf fractions. In the in vitro study, mono-butyl phthalate (MBP), a metabolite of DBP, caused a depletion of iron in the plasma Tf, although a direct release of iron from Tf was not detectable. When erythrocytes from DBP-treated rats and erythrocytes preincubated with MBP both were incubated with NPC, respectively, the Hb was decomposed and the iron also accumulated in the cell debris. However, when the two kinds of erythrocytes were incubated with SC, respectively, no decomposition of Hb was observed at low and medium doses, but the highest dose induced an accumulation of iron to Tf. Therefore, the NPC may contribute in part to the decomposition of DBP- or MBP-affected erythrocytes.

[Liver resection in a case of multiple liver metastases of gastric cancer following hepatic arterial infusion chemotherapy]

A 61-year-old-man underwent subtotal gastrectomy (D2) for advanced gastric cancer with multiple liver metastases. After the operation, repeated hepatic arterial infusion chemotherapy was performed employing implantable catheter and port system with CDDP and MMC. The result was that the liver tumors showed a remarkable regression in size, and the serum CA 19-9 level decreased within normal range. But the tumor in the lateral segment grew and the CA 19-9 level increased again. There was no evidence of metastasis or recurrence except in the liver, and the metastatic tumors in right lobe became smaller by hepatic arterial infusion chemotherapy at this time. Therefore, lateral segment resection was performed for reductive surgery 14 months after the first operation. After that, the liver tumors did not grow and CA 19-9 kept within the normal range, while hepatic arterial infusion chemotherapy could be given. Thus, it seems that liver resection for reduction surgery following hepatic arterial infusion chemotherapy should be considered as a treatment for multiple liver metastases.

[A Japanese family with probably autosomal dominant adult-onset leukodystrophy]

We report here a family with leukodystrophy clinical features of which are characterized as adult onset, probably autosomal dominant inheritance, hyperreflexia, cerebellar ataxia, autonomic dysfunction and no peripheral nerve involvement. T2-weighted brain MRI revealed diffuse high signal areas in the cerebral white matter. The disorder in our subjects can be distinguished from most leukodystrophies in terms of genetic inheritance, clinical manifestations and laboratory data. Our family is quite similar to the kindred which Eldridge et al. described in 1984 as "hereditary adult-onset leukodystrophy simulating chronic progressive multiple sclerosis". Our family is the third report of this type of leukodystrophy and the first among non-Irish/Scottish family.

Expression of perforin in nasal lymphoma. Additional evidence of its natural killer cell derivation

Eight patients with nasal lymphoma in whom fresh-frozen tissues were available were studied to elucidate the nature of the lymphoma cells. Two cases were diagnosed as diffuse, large cell lymphoma, and the remaining six cases as diffuse, mixed cell types. Immunohistochemical studies revealed that all of the cases were positive for perforin, which is a specific marker for cytotoxic T or natural killer (NK) cells. As all of the cases were CD8 negative, the perforin-positive finding further confirmed the concept that nasal lymphoma is a distinct neoplastic entity derived from NK or NK-related cells. Light microscopic immunohistochemical studies revealed that these nasal lymphoma cases could be classified into Leu19(CD56)+Leu4(CD3)+ (two cases) and Leu19(CD56)+Leu4(CD3)- (six cases) types according to the phenotypes of the proliferating cells. However, simultaneous staining for perforin and Leu4 (CD3) using immunoelectron microscopy on the Leu19+Leu4+ cases showed that the perforin-positive cells were different from the Leu4-positive cells. This finding suggests that the Leu4-positive cells are not neoplastic NK cells but reactive T cells. Six cases were positive for EBER-1 by in situ hybridization analysis. This finding reconfirms the previous studies that Epstein-Barr virus plays a significant role in the pathogenesis of nasal lymphoma.

Familial occurrence of electrocardiographic abnormalities of the Brugada-type

Electrocardiographic abnormalities were pointed out in a 51-year-old Japanese male whose major complaint was dizziness. His electrocardiogram showed a complete right bundle branch block, and a prolonged His bundle-ventricle (HV) interval of 100 msec. Two members of his family died of heart disease and 3 members, including a case of sudden death, presented an abnormal electrocardiogram of the Brugada-type with persistent ST segment elevation in the right precordial leads and right bundle branch block. The signal-averaged examination was made in the children of cases that died with the diagnosis of sudden death. Four cases showed a tendency of delay in the HV interval and a positive finding in the late potential. Further studies are necessary to clarify the relationship between electrocardiographic abnormalities of the Brugada-type and atrioventricular conduction disorder as well as to clarify the genetic basis of this disorder.

Developmental toxicity of concanavalin A in rats: association with restricted migration of neural crest cells

Concanavalin A (Con A), a plant lectin, was injected iv into pregnant rats as a single dose of 5, 10 or 20 mg/kg on gestational day (GD) 8, to investigate developmental toxicity in foetuses at term and to examine histologically embryos between GD 10 and 12. There were high incidences of various malformations in the 10 and 20 mg/kg groups: externally, craniofacial dysplasia and closure defects of the ventral body wall; internally, anophthalmia and cardiovascular malformations; and in the skeleton, anomalies of the anterior region of the vertebrae and ribs. Histological examination revealed that neural crest cells (NCC) in the control embryos appeared to be streaming from the neural crest towards the ventral region on GD 10, 11 and 12, and reached the region of the branchial arches on GD 12. By contrast, those in the Con A-treated embryos were aggregated near the dorsal region on GD 10 and 11, and had not reached the destination even on GD 12. These findings suggest that pathogenesis of developmental toxicity of Con A in rats is associated with disturbance of NCC migration and inhibition of their pluripotentiality at the destination.

Expression of inter-alpha-trypsin inhibitor light chain (bikunin) in human pancreas

Expression of inter-alpha-trypsin inhibitor light chain (ITI-LC, also known as bikunin or urinary trypsin inhibitor) was examined in various human tissues. By reverse-transcription polymerase chain reaction, the mRNA was detected not only in the liver, a known site of ITI-LC production, but also in the kidney, heart, lung, and pancreas. By RNA blot analysis, the mRNA was also detected in the pancreas and liver, but not in the kidney, heart, or lung. The ITI-LC protein was immunohistochemically detected along the surface of pancreatic acinar cells. These results indicate the apparent expression of the gene for ITI-LC in the pancreas. ITI-LC protein on the surface of pancreatic acinar cells may play an important role in preventing autodigestion by exocrine enzymes such as trypsinogen and chymotrypsinogen.

Interactions between insulin-like growth factor-I (IGF-I) and the renin-angiotensin system in follicular growth and ovulation

The interactions between insulin-like growth factor-I (IGF-I) and the renin-angiotensin system (RAS) in follicular growth and ovulation were studied with the use of an isolated perfused rabbit ovary preparation. Ovulation failed to occur in either control ovaries or the experimental ovaries perfused with IGF-I in a concentration of 1, 10, or 100 ng/ml in the absence of gonadotropin. Exposure to IGF-I stimulated the secretion rate of angiotensin II-like immunoreactivity (Ang II-IR) in perfused rabbit ovaries in a dose-dependent manner. The percent increase in follicle diameter in ovaries perfused with IGF-I for 12 h was significantly correlated with the secretion rate of Ang II-IR at 12 h after exposure to IGF-I. The addition of IGFBP-3 to the perfusate did not induce ovulation in the absence of gonadotropin, but exposure to IGFBP-3 inhibited hCG-induced ovulation in a dose-dependent manner. In addition, IGFBP-3 significantly reduced the ovarian secretion rate of Ang II-IR and prostaglandins stimulated by hCG administration. Intrafollicular plasminogen activator (PA) activity significantly increased within 4 h after exposure to 100 ng/ml of IGF-I, compared with that in control ovaries perfused with medium alone. The concomitant addition of IGFBP-3 to the perfusate significantly reduced the IGF-I-stimulated PA activity in the preovulatory follicles at 4, 6, and 8 h after exposure to IGF-I. However, IGFBP-3 alone affected neither the ovarian secretion rate of Ang II-IR nor intrafollicular PA activity. Exposure to streptokinase, an exogenous PA, in vitro stimulated both follicular growth and the intrafollicular Ang II-IR content. In conclusion, IGF-I enhances both ovarian Ang II production and follicular development by stimulating intrafollicular PA activity.

Inhibitory effect of erythromycin on ion transport by stria vascularis and vestibular dark cells

A previous study showed that systemic administration of erythromycin caused a reversible decline in the endocochlear and cochlear microphonic potentials. Those data were thought to suggest that erythromycin caused hearing loss by interference with ion transport processes in the stria vascularis. The present study was undertaken to test this hypothesis by measuring the effects of erythromycin perfused on either the apical or basolateral side on the transepithelial short circuit current (Isc), a measure of the K+ secretion rate. Isc was measured from preparations of strial marginal cells and the homologous vestibular dark cells in vitro with a micro-Ussing chamber. Erythromycin was found to have no effect when perfused on the apical side but to cause a reversible decrease in Isc when perfused on the basolateral side for both epithelia. These data are consistent with the notion that at least one ototoxic effect of erythromycin is the inhibition of K+ secretion in the inner ear.

Transcranial magnetic stimulation in an adrenoleukodystrophy patient

We experienced an 11-year-old boy diagnosed as having adrenoleukodystrophy (ALD), and studied his motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS). He had intellectual and visual impairment, and MRI revealed high intensity of the parieto-occipital white matter. On evaluation of the long tracts, slight spasticity with equivocal Babinski signs was noted: however, the long tracts appeared intact on MRI, and short latency somatosensory evoked potentials (SSEPs) were completely normal. On TMS delivered through a circular coil, MEPs recorded from the relaxed first dorsal interosseous muscle showed that only the duration was significantly prolonged, which may be due to temporal dispersion of descending volleys in the pyramidal tracts, while the latency was not prolonged. TMS in ALD was considered sensitive and useful for detecting subtle involvement of the long tracts.

[A case of progressive multifocal leukoencephalopathy with methionine uptake demonstrated by PET]

We report here a 55-year-old man with progressive multifocal leukoencephalopathy (PML) associated with chronic adult T cell leukemia (ATL). Neurological examination revealed mild dementia, right homonymous hemianopsia and visual agnosia. Serologically anti-HTLV-I antibody was positive. Peripheral blood analysis showed ATL cells up to 23% in white blood cells. Because he did not have symptoms or signs directly related to ATL, it was considered that he had chronic ATL. T2-weighted cranial MRI demonstrated multiple hyperintensity lesions confined to the white matter from the bilateral occipital to parietal lobes, without enhancement after gadolinium administration or mass effect. We performed stereotactic biopsy of the left occipitoparietal white matter. Histological examination of the biopsied specimens showed demyelinated lesions, containing foamy macrophages and bizarre astrocytes. Oligodendrocytes contained nuclear inclusions which reacted with an antibody against the JC virus (JCV) antigen. These findings were consistent with those of PML. The genomic analysis of JCV from the biopsied brain revealed deletions in the regulatory region. We investigated cerebral blood flow, glucose and amino acid metabolism in this patient using positron emission tomography, and obtained the following three characteristic findings in the lesions: 1) luxury perfusion state, 2) decreased fluorodeoxyglucose (FDG) uptake, and 3) increased methionine (Met) uptake. These findings resembled those of low grade tumors.

[Recanalization of dural sinus occlusion following the disappearance of dural arteriovenous fistula: report of a case]

A 73-year-old female was admitted to our hospital because of disturbed consciousness and left-sided motor weakness. Computed tomographic scans demonstrated a hemorrhagic infarction in the right parietal region. Right carotid angiograms showed both the posterior portion of the superior sagittal sinus (SSS) and the entire left transverse sinus simultaneously occluded. Left carotid angiograms revealed an enlarged occipital artery, which had direct communications to the left sigmoid sinus and the superior petrosal sinus. These findings were consistent with dural arteriovenous fistula (D-AVF). The laboratory examinations yieled normal results. The patient was managed conservatively with glyceol and anticonvulsants for four weeks and eventually recovered with complete resolution of hemiparesis. Follow-up angiography carried out 6 weeks later showed the SSS, partially stenotic, but recanalized with no evidence of venous congestion. The D-AVF still remained opacified, but there was a marked reduction in retrograde flow to the sigmoid sinus. Further repeated angiograms obtained at 10 months after the onset confirmed complete recanalization of the SSS and disappearance of the D-AVF. From the timing of the angiographies, we considered that the sinus occlusion was caused by the high arterial flow to the fistula and its disappearance made recanalization of SSS possible.

[Saccular aneurysm associated with fenestration of the distal segment of basilar artery]

A 32-year-old man who presented with subarachnoid hemorrhage was found to have a saccular aneurysm arising from the proximal end of the fenestration formed at the distal third of basilar artery. The aneurysm dome was directed anteriorly and measured 3mm in diameter. It was successfully clipped via subtemporal transtentorial approach and the patient returned to his previous job. Basilar artery fenestration is angiographically found in 0.23-0.6%. The fenestration is most frequently located in the proximal basilar trunk close to the vertebro-basilar junction. In this report a rare case with an aneurysm associated with fenestration in the distal part of the basilar artery will be presented.

Purification and characterization of protein phosphatase 2C in rat parotid acinar cells: two forms of Mg(2+)-activated histone phosphatase and phosphorylation by cAMP-dependent protein kinase

Two forms of Mg(2+)-activated histone phosphatase activities were partially purified from rat parotid acinar cells using Mono Q and gel filtration chromatography. Both enzymes activities were dependent on the presence of Mg2+, showing little activity in the presence of EDTA. The activities fractionated on the Mono Q column into two peaks: the first was a minor peak of histone phosphatase activity; the second was a major peak. These two peaks eluted at distinct positions on the gel filtration column. The molecular masses of the two peak fractions corresponded to 46 and 55 kDa, respectively on SDS-gels. The first 46-kDa peak immunoreacted with anti-PP2Calpha phosphatase antibody and like PP2Calpha phosphatase could be phosphorylated by cAMP-dependent protein kinase. The second 55-kDa peak showed neither reactivity with anti-PP2Calpha phosphatase antibody nor phosphorylability by cAMP-dependent protein kinase, but retained a Mg2+ or Mn2+ dependence for its histone phosphatase activity. Ca2+ showed a strong inhibition on this activity. On the basis of these observations, we have identified the first peak enzyme as PP2Calpha phosphatase and the second peak as a novel PP2C-like phosphatase.

[A case of central homonymous hemianopsia due to cerebral infarction of the occipital tip]

A 54-year-old man was admitted to the hospital because of the restriction of the right visual field. Goldmann's visual field test revealed the right central hemianopsia. MRI showed the infarction of the left occipital lobe tip. Cerebral angiography showed the occlusion of the left calcarine artery but no abnormality in the branches of the middle cerebral artery (MCA). The occipital lobe tip receives the projection from the macular area and is supplied by both calcarine artery and a branch of MCA. Therefore, cases of central homonymous hemianopsia due to vascular disorders have been relatively rare and the macular vision is usually spared. In contrast to the above knowledge, only one artery occlusion resulted in the central hemianopsia in our case. Poor anastomosis between PCA and MCA in the occipital tip of our patient may explain occurrence of the infarction of that area.

[The clinical value of BMIPP on the evaluation of myocardial ischemia and metabolism before and after CABG]

To evaluate the clinical usefulness of BMIPP (15-(p-[125I]-iodophenyl)-3-R, S-methylpentadecanoic acid), BMIPP and T1 imaging were underwent before and after surgery in 25 CABG patients. Preoperatively the demonstrated lesion on BMIPP scintigram is almost the same as that on rest-T1 scintigram. A month after CABG, the recovery on T1 scintigram was remarkable, however improvement on BMIPP was limited. These results suggest that on the evaluation of myocardial ischemia, the clinical value of BMIPP is almost the same as that of rest-T1 before CABG. The postoperative discrepancy between T1 and BMIPP scintigram suggests that the restoration of myocardial circulation does not directly improve myocardial metabolism.