Maxi-K+ channel in single isolated cochlear efferent nerve terminals

Patch clamp recordings were obtained from isolated cochlear efferent nerve terminals. Channel activity was found in 85% of membrane patches, was present in on-terminal and excised patches and was characterized to originate from a maxi-K+ channel. An average of 2.0 +/- 0.1 (N = 33) maxi-K+ channels were found per active patch. In symmetrical solutions, the current-voltage relationship was linear and the single-channel conductance was 221 +/- 5 pS (N = 22). The open probability of the maxi-K+ channel increased with depolarization of the membrane potential and with an increasing free Ca2+ concentration on the cytosolic side. The open probability was insensitive to changes in the free Ca2+ concentration on the extracellular side. TEA (20 mM) and charybdotoxin (10(-7) M) decreased the open probability to nearly zero from the extracellular side but had no effect from the cytosolic side. The high incidence with which this channel was found suggests that the maxi-K+ channel is physiologically relevant which might include protection against overstimulation of the efferent synapse.

[Effects of ascorbic acid on trace element metabolism in the choroid-retina of streptozotocin-induced diabetic guinea pigs]

In order to investigate the effect of ascorbic acid on trace element metabolism in the choroid-retina, experimental diabetes mellitus was induced in Hartley guinea pigs with intraperitoneal injection of streptozotocin. After 4 weeks, ascorbic acid-deficient feed was given for 3 weeks. Trace elements of the choroid-retina were measured with inductively-coupled plasma emission spectrometry. The activity of superoxide dismutase and lipid peroxide content also were measured. The results indicated that zinc and magnesium increased in diabetes mellitus. However, with ascorbic acid deficiency in diabetes mellitus, zinc and magnesium significantly decreased. On the other hand, the activity of superoxide dismutase showed no change between either condition and lipid peroxide content decreased under ascorbic acid deficiency in diabetes mellitus. These findings suggested that ascorbic acid played an important role in chorioretinal damage of diabetes mellitus. However, it was also suggested that lipid peroxide has little influence on the choroid-retina under these conditions.

Relationship between hind-limb muscle atrophy and serum enzymes in tail suspended rats

Many studies on the effects of gravity have been reported using animals or human being since the gravity influences the biological body in space. Especially suspension techniques for rat have been used as a microgravity simulation. This study is a report on the relation between serum enzymes such as CK and muscle atrophy, caused by tail suspension in rats.

Influence to organs by ten weeks tail suspension

The subject of atrophy has been the focus of interest for morphologists as well as the scientist in the space medicine. Muscle atrophy was noted to be some influence of microgravity in the space. Using tail suspension techniques, we have studied the influence of gravity to rats. In the present study, we tried to study the influence of the long term microgravity, ten weeks tail suspension.

Atypical beta-adrenoceptor- (beta 3-adrenoceptor) mediated relaxation of canine isolated bronchial smooth muscle

To determine whether atypical beta-adrenoceptors (beta 3-adrenoceptors) exist in the airway smooth muscle, we studied isolated bronchial segments from dogs under isometric conditions in vitro. Addition of beta-adrenoceptor agonists produced a concentration-dependent relaxation of tissues precontracted with 10(-5) M acetylcholine, rank-order potency being isoproterenol (1) > or = salbutamol (0.95) > or = BRL 37344, a beta 3-selective adrenoceptor agonist (0.83) > norepinephrine (0.10). Under the condition that alpha- and beta 1-adrenoceptors had been blocked, the relaxant response to salbutamol was competitively antagonized by the beta 2-adrenoceptor antagonist ICI 118551 and the pA2 was 7.01 +/- 0.25 (SE), whereas the response to BRL 37344 was resistant, with an apparent pA2 of 5.66. However, cyanopindolol, an antagonist for atypical beta-adrenoceptors, antagonized the BRL-induced relaxation in a competitive manner, with a pA2 of 6.74 +/- 0.11. This pA2 was lower than that when salbutamol was used as an agonist (P < 0.05). Intracellular adenosine 3',5'-cyclic monophosphate (cAMP) levels were increased by BRL 37344 in a concentration-dependent fashion. These results suggest that beta 3-adrenoceptors may exist in canine bronchial smooth muscle and that the stimulation of this type of receptor causes a bronchodilation through a cAMP-dependent pathway.

Effect of L-dopa on human muscle sympathetic nerve activity

This study was undertaken to clarify the mechanism of orthostatic hypotension, one of the side effects frequently encountered after administration of levodopa (L-dopa). Muscle sympathetic nerve activity (MSNA) was measured concomitantly with blood pressure (BP), heart rate (HR) and calf blood flow (calf BF). The responses of these variables to head-up tilting (HUT) were analyzed before and after intravenous administration of L-dopa (50 mg) in eight healthy subjects. L-dopa induced significant increases in MSNA, with concomitant decreases in BP and no changes in calf BF in the supine position. At each angle of HUT, both MSNA and the calf BF increased, following administration of L-dopa. The pattern of MSNA changes was dissociated from that of the calf BF under the influence of L-dopa. These results suggest that peripheral, rather than central, mechanisms are involved in L-dopa-induced orthostatic hypotension.

Esophagitis in infants with hypertrophic pyloric stenosis: a source of hematemesis

This study was undertaken to clarify the source of blood in the vomitus of patients with hypertrophic pyloric stenosis (HPS). Twenty-one infants with HPS were examined. Hematemesis was noted in 14 infants. Esophagogastric endoscopy showed a 100% incidence of esophagitis and in one patient gastric erosion was also observed. Histological study of the esophageal mucosa showed evidence of esophagitis in 18 patients (85.7%). Preoperative pH monitoring showed gastroesophageal reflux (GER) in all infants. Excessive acid exposure (> or = 7%) was significantly correlated with the grade of esophagitis and the incidence of hematemesis, whereas acid exposure time was shorter in the cases without histological esophagitis. These results suggested that the source of bleeding in HPS is the esophageal mucosa affected by esophagitis secondary to excessive acid reflux. Although there is obvious massive gastroesophageal reflux in HPS, it is too difficult to evaluate the lower esophageal sphincter function in HPS.

Gene structure and expression of rice seed allergenic proteins belonging to the alpha-amylase/trypsin inhibitor family

Genomic and two novel cDNA clones for rice seed allergenic protein (RA) belonging to the alpha-amylase/trypsin inhibitor family were isolated and their nucleotide sequences determined. Ten cysteine residues deduced from nucleotide sequences were completely conserved among three cDNA clones including a clone, RA17, reported previously. One genomic clone, lambda 4, contained two RA genes, RAG1 and RAG2. Although RAG1 was cloned at the 5' portion only, two RA genes were arranged divergently. Nucleotide sequencing and DNA blotting analyses showed that RA are encoded by a multigene family consisting of at least four members. The transcriptional initiation site of RAG1 was localized at A, 26 bp upstream of the putative translational initiation codon, ATG, by the primer extension assay. The putative TATA box and CAAT box existed about 45 bp and 147 bp upstream of the transcription initiation site, respectively. A conserved sequence (ATGCAAAA) which was similar to the sequence (TGCAAAA) identified in rice glutelin promoters was observed in the 5' region of the two genes. In addition, RNA blotting analyses provided that RA genes specifically expressed in ripening seed and their transcripts accumulated maximally between 15 and 20 days after flowering.

Effect of metoclopramide on muscle sympathetic nerve activity in humans

For determining the effect of the activation of the central cholinergic system on the sympathetic nervous system, we measured muscle sympathetic nerve activity (MSNA) together with heart rate and blood pressure before and after an intravenous injection of metoclopramide. Immediately after metoclopramide injection, short-term increases in MSNA and heart rate followed a transient decrease in blood pressure, suggesting that increased sympathetic nerve activity may result from the unloading of arterial baroreceptors. Approximately 7 min after injection, MSNA and heart rate were again notably increased, followed by an increase in blood pressure. This late increase in MSNA may result from central activation of the sympathetic nervous system, but not as a result of the unloading of arterial baroreceptors. The results of this study suggest that metoclopramide activates the sympathetic nervous system by mediating the central cholinergic system in humans.

Involvement of nitric oxide pathway in the PAF-induced relaxation of rat thoracic aorta

1. The mechanism of the vasorelaxant effect of platelet activating factor (PAF) on rat thoracic aorta and the effect of aging on the PAF-induced relaxation were investigated. 2. PAF at concentrations causing relaxation induced marked increases in guanosine 3':5'-cyclic monophosphate (cyclic GMP) production, but did not induce an increase in adenosine 3':5'-cyclic monophosphate (cyclic AMP). 3. Removal of the endothelium by mechanical rubbing, and treatment with the PAF antagonists CV-3988, CV-6209 and FR-900452, the nitric oxide biosynthesis inhibitor, NG-nitro L-arginine, the radical scavenger, haemoglobin, and the soluble guanylate cyclase inhibitor, methylene blue, inhibited PAF-induced relaxation and abolished or attenuated PAF-stimulated cyclic GMP production. 4. The relaxation was greatest in arteries from rats aged 4 weeks. With an increase in age, the response of the arteries to PAF was attenuated. 5. Endothelium-dependent cyclic GMP production also decreased with increase in age of the rats. 6. These results suggest that PAF stimulates production of nitric oxide from L-arginine by acting on the PAF receptors in the endothelium, which in turn stimulates soluble guanylate cyclase in the smooth muscle cells, and so increases production of cyclic GMP, thus relaxing the arteries. Age-associated decrease in PAF-induced relaxation may result from a reduction of cyclic GMP formation.

Phylogeny of regulatory regions of vertebrate tyrosinase genes

Highly homologous DNA elements were found to be shared by the upstream regions of the mouse tyrosinase and tyrosinase related protein (TRP-1) genes. Several nuclear proteins were shown to bind to both of these upstream regions. Shared homologous DNA elements were also found in the 5' flanking sequences of Japanese quail and snapping turtle tyrosinase genes. Shared homologous nucleotide sequences were found to be scattered like an archipelago in the 5' upstream regions of mouse and human tyrosinase genes. Comparisons between Japanese quail and snapping turtle tyrosinase genes gave similar results. On the contrary, mammalian (mouse and human) and nonmammalian (quail and snapping turtle) tyrosinase genes did not show significant homology in their 5' upstream regions. In contrast, coding sequences in the first exons of vertebrate tyrosinase genes and their deduced amino acid sequences were found to be highly conserved except for their putative leader sequence-coding regions.

Meningioma in a neonate: case report

A 10-day-old female with a parasagittal meningioma presenting as a subcutaneous tumor is reported. Meningiomas within the 1st month of life are rare. The clinical and pathological characteristics of congenital meningioma are reviewed.

[The 5th report on long-term chemotherapy using erythromycin (EM) for chronic lower airway infection--cases followed over 7 years]

Clinical studies were made over 7 years on 9 cases to whom long-term chemotherapy with EM was administered for chronic airway infection. 1) Clinical effectiveness: Highly effective in 8 cases; Improvement in QOL was observed in 8 cases. Bacteriological effect: In 7 cases, pathogenic bacteria disappeared. 2) No side effects were observed. 3) Changes in PaO2 levels with the passage of time: In most cases, PaO2 reached a plateau within 1 year. Although in some cases, there was subsequent elevation. 4) The frequency of catching cold over the 7 years period was low with an average of 1.2 times/year per subject. In only 2 cases were subject hospitalized due to acute exacerbation triggered by a cold. 5) Mucociliary transport improved in 7 out of 8 cases examined. However, only 4 of these recovered normal transport. The effect of EM in the other cases in which clinical improvement was not demonstrated was deemed slightly effective. On the basis of the above findings, it was suggested that long-term chemotherapy using EM was clinically efficacious. This is based on the fact that its efficacy, including amelioration of QOL appeared within one year of the initiation of therapy, and continued without decline for over 7 years.

Nitric oxide synthase responsible for L-arginine-induced relaxation of rat aortic rings in vitro may be an inducible type

1. Characteristics of L-arginine-induced non-endothelial nitric oxide (NO) formation in rat isolated thoracic aorta were investigated. 2. Relaxation to L-arginine in arterial rings devoid of endothelium developed about 2 h after the first challenge with L-arginine and reached a maximum after a further 4 h of incubation. 3. After the arteries had relaxed in response to L-arginine, guanosine 3':5'-cyclic monophosphate (cyclic GMP) production was stimulated. In fresh arteries that had not yet relaxed in response to L-arginine, L-arginine failed to elevate cyclic GMP levels. 4. Glucocorticoids, actinomycin D and polymyxin B prevented the development of L-arginine-induced relaxation and L-arginine-stimulated increase in cyclic GMP formation. 5. Once L-arginine-induced relaxation developed, these agents no longer suppressed the relaxation and increase in cyclic GMP formation to L-arginine. 6. From these results, it is suggested that in the isolated thoracic aorta of the rat, endotoxin in the medium triggers induction of a non-endothelial NO synthase during prolonged incubation, which accelerates production of NO from added L-arginine to cause relaxation of the arteries via cyclic GMP. Glucocorticoids and protein synthesis inhibitors may prevent induction of NO synthase. It is suggested that the NO synthase mediating the production of muscle-derived NO from L-arginine is an inducible type.

[A report of two cases of multilocular cystic renal cell carcinoma: review of 51 cases reported and the results of a prognostic survey]

We report 2 cases of multilocular cystic renal cell carcinoma. One was in a 33-year-old male, presenting with ultrasonic abnormality of the left kidney at an annual employee health care examination. Computerized tomography (CT) demonstrated a 5 cm of multilocular cystic mass adjacent to the lower pole of the left kidney. Another was in a 44-year-old male, presenting with microscopic hematuria at an annual employee health care examination. CT of the abdomen revealed a 6.5 cm of multilocular cystic mass on the upper pole of the right kidney. Both were diagnosed as renal cell carcinoma by the angiography and underwent radical nephrectomy. Gross specimens showed typical multilocular cystic appearance and histopathology showed clear cell carcinoma infiltrating septa and replacing epithelium of the cyst walls. Both patients are alive without evidence of disease at, 21 months and 14 months after operation, respectively. Including our cases, 51 multilocular cystic renal cell carcinoma and multilocular cystic nephroma associated with renal cell carcinoma have been reported. From the review of the literatures and the answer of the questionnaires inquiring about the outcome of the patient to Japanese reporters, the outcome of 38 patients was ascertained. The 10-year survival rates and non-recurrence rate after operation calculated by the Kaphan-Meier formula were 97.3% and 90.3%, respectively. Because of the good prognosis of reported cases, we concluded that we should choose kidney-sparing surgery for the operation of multilocular cystic renal cell carcinoma.

[Attempt for modified radical mastectomy in the treatment of early breast cancer]

Until five years ago the Aichi Cancer Center had adopted the standard radical mastectomy where breast, major and minor pectoral muscles, and axillary adipose tissues were resected en bloc. In case tumor was found at the inner half or the center of the breast, parasternal lymph node dissection was concomitantly carried out. Recently, however, we begin to perform Auchincloss by which major and minor pectoral muscles can be conserved, as an attempt for modified radical mastectomy. In some cases, furthermore, breast conserving operation is made. The reasons why we changed the operation methods are: 1) Due to the advancement of diagnostic imaging and widespread self examination, percentage of early breast cancer has considerably increased. 2) Postoperative adjuvant therapy, especially adjuvant endocrine therapy, has remarkably progressed.

[Clinical assessment of urinary free L-fucose levels]

We measured urinary levels of free L-fucose in healthy subjects, patients with benign diseases, and patients with cancer using an automated analyzer and a newly isolated L-fucose dehydrogenase, and evaluated the clinical usefulness of the results. The values obtained were corrected for urinary creatinine as micromoles per gram of creatinine. The cutoff value, set at the mean + 2SD for the healthy subjects, was 250 mumol/g.Cr. Patients with gallbladder cancer, bile-duct cancer, liver cancer, pancreatic cancer, or cirrhosis of the liver had significantly higher levels of L-fucose than the healthy subjects. The diagnostic sensitivity for these five diseases, taken together, was 68% (144/213). Specificity for the detection of cancer was calculated by use of false positives for patients with cholelithiasis, hepatitis, and pancreatitis: it was 73% (76/104). Diagnostic accuracy for these seven diseases taken together was therefore 69% (220/317). We compared the positive ratio of the L-fucose level with that of the tumor markers AFD and CA19-9. The positive ratio of an L-fucose value above the cutoff was higher than the positive ratio of either marker in bile-duct cancer, gallbladder cancer, liver cancer, and pancreatic cancer. The results suggested that the urinary levels of free L-fucose reflected the metabolism of sugar chains of glycoconjugates, and may be usefully clinically as a tumor marker.

[Long-term chemotherapy using erythromycin (EM) for chronic lower airway infection: effectiveness of clarithromycin in EM ineffective cases--the fourth report]

The effectiveness of long-term chemotherapy using Erythromycin (EM) for chronic lower airway infection has been practically proved. However, there still exist some ineffective cases, or cases in which the clinical effect was scarcely seen. In the present study was administered Clarithromycin (CAM) to such cases and found that CAM was effective in alleviating symptoms in some of them. The results were presented along with clinical findings and other basic studies. The subjects were 4 cases in which EM was either ineffective or low in its clinical effect. The subjects consisted of 1 case of DPB and 3 cases of bronchiectasis. EM was clinically ineffective in 2 cases and slightly effective in the two others. The pathogen was Pseudomonas aeruginosa in all cases. The dosage of EM was 200-1200 mg/day. The period of administration ranged from 2 years to 6 years 9 months. CAM was given orally after meals at a dose of either 200 or 400 mg/day. Chemotherapy had continued for 3-8 months at the time of final observation (Feb. 1992). Clinical effectiveness was evaluated on the basis of sputum volume and PaO2 examination, as well as evaluation by the patients themselves. As a result, in all 4 cases, reduction in sputum volume and improvement of PaO2 were observed. All subjects evaluated CAM therapy as being more effective than EM therapy. Moreover, it was found that CAM inhibited both the elastase and leucocidin produced in one of the ineffective cases by P. aeruginosa, whereas EM didnt.(ABSTRACT TRUNCATED AT 250 WORDS)

[A clinical study of the continuous intra-arterial infusion chemotherapy of Ewing's sarcoma]

Eight cases of Ewing's sarcoma were treated by continuous intra-arterial infusion chemotherapy (i.a. infusion). Five cases gave no evidence of disease (mean 4 yr. 7 mos.), and 3 cases died (3 mos, 1 yr. 11 mo, 2 yrs. 5 mos.). The term of i.a. infusion was 3 mos. to 2 yrs. 3 mos. (mean 12 mos). Except in 2 cases, the primary tumors were suppressed by i.a. infusion, so these cases were not operated and no relapse resulted. The cumulative survival rate by Kaplan-Meier's method was 56.3%. The i.a. infusion for Ewing's sarcomas implies the possibility of limb-saving treatment with no operation.

Ca(2+)-activated nonselective cation, maxi K+ and Cl- channels in apical membrane of marginal cells of stria vascularis

Patch clamp recordings on the apical membrane of marginal cells of the stria vascularis of the gerbil were made in the cell-attached and excised configuration. Marginal cells are thought to secrete K+ into and absorb Na+ from endolymph. Four types of channel were identified; the most frequently observed channel was a small, nonselective cation channel which was highly similar to that found in the apical membrane of vestibular dark cells (Marcus et al., (1992) Am. J. Physiol. 262, C1423-C1429). The small nonselective cation channel was equally conductive (26.7 +/- 0.3 pS; N = 49) for K+, Na+, Rb+, Li+ and Cs+, 1.6 times more permeable to NH4+, but not permeable to Cl-, Ca2+, Ba2+ or N-methyl-D-glucamine. This channel yielded linear current-voltage relations which passed nearly through the origin (intercept: -2.2 +/- 0.4 mV, N = 49) when conductive monovalent cations were present on both sides of the membrane in equal concentrations. Channel activity required the presence of Ca2+ at the cytosolic face but not the extracellular (endolymphatic) face; there was essentially no activity for cytosolic Ca2+ less than or equal to 10(-7) M Ca2+ and full activity for greater than or equal to 10(-5) M. Cell-attached recordings had a conductance of 28.6 +/- 2.2 pS (N = 6) and a reversal voltage of -2.2 +/- 5.2 mV (N = 3) which was interpreted to reflect the intracellular potential of marginal cells under the present conditions. The three other types of channel were a Cl- channel (approximately 50 pS; N = 2), a maxi-K+ channel (approximately 230 pS; N = 1), and another large channel, probably cation nonselective (approximately 170 pS; N = 1). The 27 pS nonselective cation channel may be involved in K+ secretion and Na+ absorption under stimulated conditions which produce an elevated intracellular Ca2+; however, consideration of the apparent channel density in relation to the total transepithelial K+ flux suggests that these channels are not sufficient to account for K+ secretion.

[Changes in serum cytokine levels in patients with malignant bone and soft tissue tumors in the course of chemotherapy]

We studied seven patients with malignant bone and soft tissue tumors to examine the influence of chemotherapy on production of serum cytokines. Four types of cytokines (IL-1 beta, IL-2, IL-6, TNF alpha) were measured by ELISA method. A significant increase of IL-6 and TNF alpha production was observed after intravenous infusion of antitumor drugs. After intraarterial infusion of drugs there was a slight increase in the production of these cytokines. On the other hand, there were no changes in the IL-1 beta and IL-2 levels after infusion of the drugs. IL-6 and TNF alpha increased almost at the same time that the numbers of WBC (neutrophils) decreased after infusion. And this phenomenon was clear in the patients who had a good performance status.

The strain-dependent constitutive expression of murine serum amyloid-P component is regulated at the transcriptional level

The strain-dependent expression of murine serum amyloid P-component (SAP) has been known to be linked to the Sap locus. We have quantified the SAP mRNA in several inbred strains including DBA/2 and C57BL/6 mice which represent high and low producers of SAP at resting state, respectively, and found that the mRNA levels correlated well with the amount of SAP protein. Interestingly, the SAP mRNA level of F1 mouse between DBA/2 and C57BL/6 was low and similar to that of C57BL/6. Primer extension and ribonuclease (RNAase) protection analyses demonstrated that a single type of transcript was generated from the SAP gene and that the cap sites were identical regardless mouse strains tested under unstimulated and stimulated (by lipopolysaccharide (LPS) or interleukin-6 (IL-6)) conditions. To investigate possible structural difference of the SAP gene including 5' flanking region, we have cloned, sequenced and compared the SAP genes from DBA/2 and C57BL/6 mice. Sequence analyses revealed that the 5' flanking regulatory regions, as well as the coding regions, were well-conserved between the two strains. These results demonstrate that the strain-dependent SAP expression occurs at the transcriptional level but seems to be affected by neither different type of the transcripts nor structural difference of the 5' flanking and coding regions of the SAP gene. It was suggested that a possible transcription factor with suppressive activity, which is encoded by a gene linked to Sap, may be involved.