Effects of efonidipine hydrochloride (NZ-105), a new calcium antagonist, against acute renal failure in rats

1. We investigated the effect of efonidipine hydrochloride (NZ-105) against acute renal failure (ARF) in male Wistar rats. ARF was produced by ischemia or glycerol. 2. Ischemia-induced ARF was produced by right nephrectomy and clamping of the left renal artery for 60 min, followed by reperfusion. NZ-105 (20 mg/kg) was orally administered twice a day for 3 days before ARF. The plasma creatinine and urea nitrogen concentrations were markedly elevated in the ischemia ARF group on the 1st day, but the elevation was significantly suppressed by NZ-105 treatment. 3. Glycerol-induced ARF was produced by intramuscular injection of 50% (v/v) glycerol (10 ml/kg) in rats which were restricted to drinking water for 24 hr. NZ-105 (20 mg/kg) was orally administered twice a day for 3 days before ARF. NZ-105 significantly attenuated the severe impairment of creatinine and urea nitrogen clearances and the elevated fractional sodium excretion (FENa) caused by ARF. 4. In the kidney homogenate, NZ-105 (10(-6)-10(-4) M) inhibited lipid peroxidation induced by ascorbic acid and Fe or by NADPH and the inhibitory effect of NZ-105 was stronger than alpha-tocopherol, an antioxidant agent. NZ-105 (10(-5)-10(-3) M) showed radical scavenging action against diphenyl-p-picrylhydrazyl and galvinoxyl induced radicals. 5. These findings suggest that NZ-105 prevents the renal damage caused by the two kinds of ARF. Moreover, the inhibitory effects of NZ-105 against lipid peroxidation and radical formation may be one of the mechanisms involved in the prevention of ARF.

Three cases of malignant hypertension: the roles of endothelin-1 and the renin-angiotensin-aldosterone system

We experienced three cases of malignant hypertension. Plasma endothelin-1 (ET-1) was extremely high in all patients on admission (12.1 +/- 1.0 pg/ml, normal 1.5 +/- 0.5 pg/ml), and changed in parallel with the serum creatinine level. In one patient, during the recovery period, serum creatinine increased 1 mg/dl over a one-week period just after the increase of plasma ET-1 (14.2 pg/ml), while plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were stable. In contrast, the decline of renal dysfunction was larger in patients with high PRA and PAC. These data suggest that increased plasma ET-1 and an enhanced renin-aldosterone-angiotensin system act together in a vicious cycle to deteriorate renal function in patients with malignant hypertension.

PCR analysis of the Y chromosome long arm in azoospermic patients: evidence for a second locus required for spermatogenesis

We analyzed DNA from 63 Japanese men with either azoospermia or severe oligospermia whose Y chromosomes were cytogenetically normal. A total of 16 loci were examined: 15 loci on the long arm between DYS7E and DYZ1, and the YRRM1 locus, a candidate gene for the azoospermic factor, AZF. One patient with a pericentric inversion of the Y chromosome was also included. We detected micro-deletions in ten individuals. The YRRM1 gene was involved in only three of them. The remaining seven patients showed deletion between DYS7C and DYS239 in common, indicating the presence of at least one additional gene, deletion of which causes azoospermia.

Alterations in plasma concentrations of natriuretic peptides and antidiuretic hormone after subarachnoid hemorrhage

BACKGROUND AND PURPOSE

Hyponatremia is a common complication after subarachnoid hemorrhage. In this study we investigated the relations among hyponatremia, plasma natriuretic peptides, and antidiuretic hormone concentrations after subarachnoid hemorrhage.

METHODS

Blood samples for radioimmunoassay measurement of plasma brain natriuretic peptide-like immunoreactivity, atrial natriuretic peptide-like immunoreactivity, and antidiuretic hormone were obtained every 2 to 4 days until day 14 after subarachnoid hemorrhage.

RESULTS

Eleven of 20 patients with verified subarachnoid hemorrhage demonstrated mild hyponatremia (126 mEq/L < serum sodium < 135 mEq/L) during their clinical course. Atrial natriuretic peptide and antidiuretic hormone concentrations were significantly elevated on days 0 to 2 after onset of subarachnoid hemorrhage. Atrial natriuretic peptide concentrations remained high in patients who developed mild hyponatremia on days 6 to 14 after onset of subarachnoid hemorrhage. In contrast, antidiuretic hormone concentrations became significantly lower during the second week in these patients.

CONCLUSIONS

Mild hyponatremia after subarachnoid hemorrhage may be attributable not to the syndrome of inappropriate secretion of antidiuretic hormone but to cerebral salt-wasting syndrome. Atrial natriuretic peptide may be a causal natriuretic factor in cerebral salt-wasting syndrome.

Total synthesis of a modified ganglioside, de-N-acetyl GM2

Regio- and stereo-selective glycosylation of a sialyl donor 6 that carries a N-phthaloyl protecting group at C-5 with a lactosyl acceptor 7 armed with a pivaloyl group at O-2a was performed to give the expected glycotrioside 5. Subsequent glycosylation of 5 with 2-azido galactosyl donor 4 gave glycotetraosyl derivatives 18 and 19. After conversion of 18 into imidates 25 and 26, coupling with (2S,3R,4E)-3-O-benzoyl-2-N-tetracosanoylsphingenine (2) was executed to afford completely protected ganglioside analogues 27 and 28. Selective cleavage of the methyl ester and N,O-deprotection gave the target de-N-acetyl GM2 (1).

Expression of mouse phosphofructokinase-M gene alternative transcripts: evidence for the conserved two-promoter system

Molecular cloning of the 5' part of mouse phosphofructokinase-M cDNA was performed. In the 46 cDNA clones isolated, there were two classes of 5' untranslated sequences. One had an EcoRI site within its 5' untranslated sequence. This showed 83.0% similarity with human type B mRNA for phosphofructokinase-M. The other lacked an EcoRI site, showing 92.9% similarity with human type C mRNA. Using the reverse-transcription PCR technique, we found that the transcript with an EcoRI site was exclusively expressed in cardiac and skeletal muscles, while that without an EcoRI site was expressed in all the mouse tissues examined. The results suggested that the mouse phosphofructokinase-M gene was transcribed through alternative splicing by the multiple promoters. This transcription mechanism was considered to be evolutionarily conserved. The level of phosphofructokinase-M gene expression in mouse cardiac and skeletal muscles decreased in the ketotic diabetic state. Although the regulatory mechanism and the physiological significance are not fully known, this would indicate that phosphofructokinase-M gene transcripts are affected during the diabetic state.

[Criteria for the evaluating treatment on primary bone sarcoma]

The criteria for the evaluation of the treatment on primary bone sarcoma proposed by the Musculoskeletal Tumor Committee of the Japanese Orthopaedic Association (JOA) were accepted in 1993 by the Joint Committee for Cancer Therapy of the Japan Society for Cancer Therapy. The responses to treatment are classified as a complete response (CR), a partial response (PR), no change (NC), or as progressive disease (PD). It is a requirement that the condition of CR, PR, or NC continues for at least 4 weeks. The radiographical criteria are as follows: CR, the disappearance of the intramedullary lesions and the bone trabeculae recovering a normal appearance; PR, the circumscription of the extraosseous tumor and an appearance of sclerotic foci within the intramedullary lesion; NC, no changes noted in the extraosseous and intramedullary lesions; PD, an increase in the extraosseous or intramedullary lesion and/or the appearance of new lesions. Histopathological criteria are as follows: CR, no tumor cells appearing viable in any of the histologic sections; PR, greater than 90% tumor necrosis attributable to treatment; NC, 50 to 90% tumor necrosis and other secondary changes attributable to treatment; PD, less than 50% tumor necrosis. Responses in the clinical signs and symptoms including tumor size (or circumference of the extremities at the site of the tumor), pain and local heat are also graded as follows: PR, subsiding symptoms and/or decrease in the tumor size; NC, neither exacerbation nor decrease in the symptoms and no change in size; PD, the exacerbation of symptoms or an increase in size. Additionally, the serum alkaline phosphatase level can be used for evaluating the effect of the treatment on the osteosarcoma. The extent of the response to preoperative chemotherapy is a powerful predictor of patient survival.

Total en bloc spondylectomy for solitary spinal metastases

We have developed a technique for total en bloc spondylectomy through a posterior approach and now report our experience of 20 patients with a solitary or localised metastasis in the thoracic or lumbar vertebrae. There are two steps: an en bloc laminectomy, followed by en bloc resection of the vertebral body with an oncological wide margin and the insertion of a vertebral prosthesis. Pain was relieved in the 17 patients who could be assessed; 11 of the 15 patients with a neurological deficit were much improved, impending paralysis being prevented in 5 patients. There have been no local recurrences. Nine patients are at present alive with a mean follow up of 17.4 months.

The NOD mouse

The NOD mouse was discovered and established as an inbred strain in Japan. It is an excellent animal model for human Type 1 (insulin-dependent) diabetes mellitus in many aspects, including genetics, immunology, virology, and prevention and therapy. The diabetes and/or insulitis is controlled by at least 10 genes and results from the T cell-mediated destruction of beta cells. Retrovirus might also play a role in the pathogenesis. Insulitis and/or diabetes of the mice is easily prevented by a number of agents or manipulations, suggesting that diabetes of the mice develops only when many diabetogenic factors assemble. Some of the intervention trials using the mice are hoped to be applied to human Type 1 diabetes.

[Heterochronic occurrence of bilateral torsion of appendix testis a case report]

An 8-year-old boy who had undergone excision of the left appendix testis for torsion of the left appendix testis about one and a half years previously was brought to our department on February 18, 1991 because of right scrotal pain of 4 days' duration. Palpation revealed induration with tenderness of the superior portion of the right testicle. A scrotal ultrasonographic tomogram revealed a shadow probably representing an enlarged appendix testis. The patient was diagnosed as having torsion of the right appendix testis. There was refractory pain, and there was possibility of reactive epididymitis. So the patient underwent excision of the right appendix testis, two right appendices testis, which had enlarged to 5 mm in diameter were found, histopathological examination revealed slight bleeding and marked edema of the stroma, which may have been caused by torsion of the appendix testis. Scrotal pain subsided postoperatively. Bilateral torsion of the appendix testis is very uncommon, and our case is the 14th case reported. Torsion of the appendix testis occasionally develops. Torsion of the appendix testis occasionally develops bilaterally. When a small, tender mass at the superior pole of testis, torsion of the appendix testis should be considered.

[The value of hepatic arterial infusion chemotherapy for liver metastases--discussion from viewpoints of prevention of hepatic death and QOL]

The value of hepatic arterial infusion chemotherapy for liver metastases was discussed from the viewpoints of the prevention of hepatic death and the negative effect on QOL, based on the results of repeated hepatic arterial infusion chemotherapy for 128 patients with unresectable liver metastases employing implantable catheter and port system. In 70% of patients, hepatic death due to metastases was prevented by this therapy, and the negative effect on QOL by this therapy was limited. Thus, in spite of the limited effects on the prolongation of survival compared with systemic chemotherapy, there is a reasonable basis for the use of hepatic arterial infusion chemotherapy as a treatment for unresectable liver metastases.

A novel hypothyroid 'growth-retarded' mouse derived from Snell's dwarf mouse

This paper describes a novel mutant mouse that has been spontaneously derived from the Snell's dwarf (DW/J) mouse. It was named the 'growth-retarded mouse' because of a characteristic growth pause followed by the delayed onset of pubertal growth. The onset of the increase in pituitary GH content that normally occurs concomitant with pubertal growth was also delayed in the growth-retarded mice. The serum concentration of thyroxine was very low in these mice from the neonatal period through adulthood, and a supplement of tri-iodothyronine was effective in shortening the growth pause and commencing the suppressed pubertal growth. Histological and immunohistochemical studies revealed that the anterior pituitary gland of the growth-retarded mouse contains clustered unusual chromophobic cells which are not reactive to various antisera against anterior pituitary hormones and the gland becomes enlarged with age. Breeding data indicated that these characteristics of the mice show an autosomal recessive inheritance and the gene responsible was designated as 'grm'. Partial linkage analysis utilizing microsatellite polymorphism demonstrated that the grm gene does not identify with the lit or hyt genes. Based on comparison of the hormonal status and growth pattern between growth-retarded, dwarf and normal mice, we have suggested the existence of a mutual interaction, possibly positive feedback regulation, between the pituitary and thyroid glands, that develops or matures the hormonal network which is responsible for rapid somatic growth and metabolic changes at puberty in mice.

PCR localization of C-type natriuretic peptide and B-type receptor mRNAs in rat nephron segments

The present study was undertaken to investigate the presence of C-type natriuretic peptide (CNP) mRNA and its receptor, natriuretic peptide B-type receptor (ANPR-B) mRNA, in rat renal structures. The microlocalization of mRNAs coding for CNP and ANPR-B was carried out in the rat kidney, using an assay of reverse transcription and polymerase chain reaction (RT-PCR) in individual microdissected renal tubule segments, glomeruli, vasa recta bundle, and arcuate arteries. The PCR signal for CNP was detected in glomerulus, vasa recta bundle, and arcuate artery. The PCR product of ANPR-B was widely present in renal structures. Relatively large amounts of ANPR-B PCR product were detected in glomerulus, vasa recta bundle, arcuate artery, and distal nephron segments. A relatively high concentration of CNP (10(-7) M) stimulated guanosine 3',5'-cyclic monophosphate accumulation in glomerulus, medullary thick ascending limb, cortical collecting duct, and inner medullary collecting duct. Our data demonstrate that CNP can be produced locally in the glomerulus and renal vascular system and that ANPR-B is widely distributed in renal structures. Thus CNP may influence renal function and act in autocrine and paracrine fashions in the kidney.

Anterior decompression and fusion for cervical myeloradiculopathy secondary to ossification of the posterior ligament

The authors reviewed 85 patients who had undergone anterior decompression and cervical fusion for myeloradiculopathy due to ossification of the posterior longitudinal ligament. There were 72 males and 13 females; the average follow up was for 8.3 years. Sixteen patients (group I) underwent one vertebra subtotal spondylectomy with fusion, 58 (group II) two vertebra subtotal spondylectomy, and 11 (group III) three vertebra subtotal spondylectomy. Neurological recovery was assessed on the grading system of the Japanese Orthopaedic Association. The patients in group I had an average improvement of 75%, in group II 72% and in group III 23%. The severity of compromise of the spinal cord did not affect the postoperative improvement. Duration of disease, previous injury and advanced neurological symptoms all affected neurological recovery. Spondylectomy of at most two vertebrae, with fusion, is recommended for ossification of the posterior longitudinal ligament. If there is more extensive involvement laminoplasty may be indicated.

Differences related to the production of arachidonic acid between collagen- and thrombin-stimulated human platelets

The effects of collagen and thrombin on the liberation of free arachidonic acid were investigated in human platelets by fluorometric high-performance liquid chromatography. Collagen induced a concentration-dependent increase in the extent of platelet aggregation, as well as an accumulation of arachidonic acid in human platelets. By contrast, thrombin effectively provoked a potent aggregation at relatively low concentration without any accumulation of free arachidonic acid, although the accumulation of arachidonic acid was detected at a high concentration of thrombin (> 0.1 U/ml) that induced full aggregation. The selective liberation of arachidonic acid was found in thrombin-stimulated platelets. Non-selective liberation of fatty acids occurred in platelets that had been stimulated with a high concentration of collagen (10 micrograms/ml), as well as in platelets stimulated with A23187. The net amount of free arachidonic acid in collagen-stimulated platelets was estimated by use of eicosatetraenoic acid (ETYA), which is an inhibitor of both cyclooxygenase and lipoxygenase. ETYA markedly potentiated the accumulation of free arachidonic acid in collagen-stimulated platelets without changing the amounts of other fatty acids in the cell.

Distribution of kallikrein-binding protein mRNA in kidneys and difference between SHR and WKY rats

We investigated kallikrein-binding protein (KBP) mRNA distribution in the kidney of Sprague-Dawley (SD) rats, spontaneously hypertensive rats (SHR), and Wistar-Kyoto strain (WKY) rats. Northern blot analysis revealed that KBP mRNA was located mainly in the medulla and with lower amounts in SHR than in WKY rats. KBP mRNA in microdissected nephron segments was detected by reverse transcription and polymerase chain reaction (RT-PCR) followed by Southern blot analysis. In SD rats, the most abundant signals were consistently found in inner medullary collecting duct (IMCD), with small amounts in outer medullary collecting duct, proximal convoluted tubule, and glomerulus. No signals were found in connecting tubule and cortical collecting duct. The nephron distribution of KBP mRNA was similar in WKY and SD rats. Only a small amount of signal was found, however, in IMCD of SHR. In conclusion, 1) KBP mRNA was predominantly distributed in the medullary segments of the distal nephron, downstream from the known kallikrein activity site in the collecting duct, and 2) KBP mRNA expression was significantly decreased in the kidney of SHR.

Crystal structure of RNase T1 complexed with the product nucleotide 3'-GMP. Structural evidence for direct interaction of histidine 40 and glutamic acid 58 with the 2'-hydroxyl group of the ribose

The crystal structure of RNase T1 complexed with 3'-GMP has been determined. The glycosyl conformation of 3'-GMP is in the syn conformation, and the ribose adopts the O4'-endo pucker. This observed pucker is different from that in any complex structures of RNase T1. In the present complex, this energetically unfavorable conformation is stabilized by the water molecule with the bridged hydrogen bonds between the O2' and the O3' atoms of the ribose. The guanine base is recognized in the same manner as observed in the complex of 2'-GMP. The 2'-hydroxyl group of the ribose shows a tight hydrogen bond to both His-40 and Glu-58 with the suitable geometry for the proton transfer. These hydrogen bonds suggest that the two residues can participate directly in the proton transfer. His-92 is hydrogen bonded to two the proton transfer. His-92 is hydrogen bonded to two oxygen atoms of the phosphate group. Based on the geometry in the active site, the O1P atom may correspond to the O5' atom of the leaving nucleotide in the phosphoryl transfer or a water molecule as a nucleophile in the hydrolysis reaction. In the present complex, the conformations of the 3'-GMP molecule and the side chains of the catalytic residues would be represented as the conformation before the phosphoryl transfer reaction and/or after the hydrolysis reaction.

[Anesthetic management of a patient with mild hypothyroidism]

A patient with mild hypothyroidism underwent a repair of abdominal aortic aneurysm. Although the serum TSH level of this patient was very high and T4, free T4 levels were low, T3 level remained within normal ranges. Inhalation anesthesia with continuous epidural block was selected and there was no complication such as hypotension or hypothermia during perioperative period. Recently, several reports demonstrate that the preoperative supplemental therapy of the thyroid hormone should not be necessary in the case of mild hypothyroidism. Moreover, the biological potency of T3 is higher than that of T4. Thus, in patients whose T3 level is kept within normal ranges even if serum T4 level is low and serum TSH level is high, we may say that they are in euthyroid state. We think these patients can be anesthetized safely.

Intermittent priapism associated with lumbar spinal stenosis

Nine patients with intermittent priapism associated with lumbar spinal stenosis are described. They had severe intermittent claudication and priapism when walking, and 7 had sensory disturbances affecting the lumbosacral nerve roots at rest. Radiographs showed degenerative central stenosis in 6, and degenerative spondylolisthesis in 3. Seven were treated by surgical decompression and 2 refused operation. Six of the 7 had improvement in their priapism, but symptoms recurred in one as a result of spondylolisthesis developing after operation.

Effects of hyperosmolality on ANP-stimulated cGMP generation in rat inner medullary collecting duct

The inner medullary collecting duct (IMCD) is a major target site of atrial natriuretic peptide (ANP) for diuresis and natriuresis, and it is in a hypertonic condition made by the renal countercurrent multiplication system. We investigated the effects of hyperosmolality on ANP-stimulated cGMP generation in IMCD and glomerulus. Hypertonic solutions (490 and 690 mOsm/kg.H2O) were made by adding NaCl or urea to isotonic solution (290 mOsm/kg.H2O). Hypertonicity of 490 mOsm/kg.H2O using NaCl reduced both ANP-stimulated guanylate cyclase activity (from 7.7 +/- 1.1 to 4.1 +/- 0.5 fmol/mm/5 min) and cGMP generation (from 1.35 +/- 0.18 to 0.48 +/- 0.20 fmol/mm/3 min) in IMCD. Hypertonicity of 690 mOsm/kg.H2O using NaCl did not further reduce ANP-stimulated cGMP generation in IMCD. Hypertonicity using urea also inhibited ANP-stimulated guanylate cyclase activity and cGMP generation in IMCD. On the other hand, hypertonicity using NaCl stimulated AVP-stimulated cAMP generation in IMCD, while hypertonicity using urea reduced it. In glomeruli, hyperosmolality of 490 mOsm/kg.H2O using NaCl also reduced ANP-stimulated cGMP generation, and hypertonicity of 690 mOsm/kg.H2O using NaCl further reduced it. In summary, hyperosmolality using NaCl and urea inhibited ANP-sensitive guanylate cyclase activity and cGMP generation both in IMCD and glomeruli. However, the mechanisms at work may be different between NaCl and urea.