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Biomedical subjects

M Hirata

Publications and source records attributed to M Hirata.

At least 271 records · Page 15Linked to original sources
PubMed1995

A novel big defensin identified in horseshoe crab hemocytes: isolation, amino acid sequence, and antibacterial activity.

Hemocytes of the horseshoe crab (limulus) contain a family of arthropodous peptide antibiotics, termed the tachyplesin family, and antibacterial protein, called anti-LPS factor, of which the former is located in the small (S) granules and the latter in the large (L) granules of the hemocytes. In our ongoing studies on granular components, we have identified here a novel defensin-like substance present in both L- and S-granules. This substance strongly inhibits the growth of Gram-negative and -positive bacteria, and fungi, such as Candida albicans. The isolated substance, tentatively termed "big defensin," consists of 79 amino acid residues, of which the COOH-terminal 37 residues have a sequence similar to those of mammalian neutrophil-derived defensins, especially rat defensin. Characterization of the disulfide motif in big defensin indicated that the disulfide array is identical to that of beta-defensins from bovine neutrophils. One clear structural difference is that the limulus hemocyte-derived big defensin has an extension of the NH2-terminal hydrophobic sequence with 35 amino acid residues followed by the COOH-terminal cationic defensin portion. This amphipathic nature of big defensin seems likely to be associated with its potent antibacterial activity. Furthermore, antibacterial activities of the NH2-terminal hydrophobic region and the COOH-terminal defensin portion separated by tryptic digestion are significantly different: the former displays a more potent activity against Gram-positive bacteria, whereas the latter is more potent against Gram-negative bacteria. Big defensin, therefore, may prove to represent a new class of defensin family possessing two functional domains with different antimicrobial activities.

Amino Acid Sequence↗
PubMed1995

Large-volume intraoperative peritoneal lavage with an assistant device for treatment of peritonitis caused by blunt traumatic rupture of the small bowel.

The benefits of large-volume intraoperative peritoneal lavage (IOPL), with an assistant lavage device, were evaluated retrospectively in 114 patients with peritonitis caused by blunt traumatic rupture of the small bowel. Postoperative complications caused by infection were a major problem after rupture of the small bowel (46 of 114, 39.4%). Both prolongation of the interval between injury and laparotomy and rupture of the lower part of the small bowel were risk factors for postoperative complications caused by infection. Large-volume IOPL (25.2 +/- 2.1 L) with an assistant lavage device reduced the rate of complications caused by infection from 30 of 58 (51.8%) to 15 of 56 (26.8%). The volume used for IOPL was closely related to the occurrence of postoperative complications resulting from infection. No complications from infection occurred in patients who received lavage with of 28.3 +/- 2.7 L of saline, whereas complications occurred in those patients treated with a smaller volume of lavage fluid (18.0 +/- 2.5 L). Large-volume IOPL should be considered in patients with blunt rupture of the small bowel who are at risk for infection, and the assistant device for IOPL may be useful for such treatment.

Adolescent↗
PubMed1995

A case of drug eruption caused by the crude drug Boi (Sinomenium stem/Sinomeni caulis et Rhizoma).

We report a case of drug eruption caused by the crude drug Boi. A 41-year-old female patient had been diagnosed with chronic rheumatoid arthritis in the department of internal medicine. After ingestion of a decoction of the crude drug Boi for the alleviation of arthralgia, a slight fever developed, which was followed by systemic edematous erythema with itching. HPLC showed that the main components of the crude drug Boi are sinomenine and magnoflorine. The results of patch tests were negative for all oral drugs that the patient had been taking. Oral ingestion tests showed that the patient showed positive reactions to the as-is Boi boiling-water decoction and 1/10-volume sinomenine. Based on this, the drug eruption was judged to be caused by sinomenine. It is considered the first time that the causative component of a drug eruption was confirmed by oral ingestion tests with components of a crude drug of Kampo medicine (Sino-Japanese traditional medicine).

Adult↗
PubMed1995

Human CAP18: a novel antimicrobial lipopolysaccharide-binding protein.

CAP18 (18-kDa cationic antimicrobial protein) is a protein originally identified and purified from rabbit leukocytes on the basis of its capacity to bind and inhibit various activities of lipopolysaccharide (LPS). Here we report the cloning of human CAP18 and characterize the anti-LPS activity of the C-terminal fragment. Oligonucleotide probes designed from the rabbit CAP18 cDNA were used to identify human CAP18 from a bone marrow cDNA library. The cDNA encodes a protein composed of a 30-amino-acid signal peptide, a 103-amino-acid N-terminal domain of unknown function, and a C-terminal domain of 37 amino acids homologous to the LPS-binding antimicrobial domain of rabbit CAP18, designated CAP18(104-140). A human CAP18-specific antiserum was generated by using CAP18 expressed as a fusion protein with the maltose-binding protein. Western blots (immunoblots) with this antiserum showed specific expression of human CAP18 in granulocytes. Synthetic human CAP18(104-140) and a more active truncated fragment, CAP18(104-135), were shown to (i) bind to erythrocytes coated with diverse strains of LPS, (ii) inhibit LPS-induced release of nitric oxide from macrophages, (iii) inhibit LPS-induced generation of tissue factor, and (iv) protect mice from LPS lethality. CAP18(104-140) may have therapeutic utility for conditions associated with elevated concentrations of LPS.

Amino Acid Sequence↗
PubMed1995

Induction of cytochrome P450 3A (CYP 3A) by E 5110, a non-steroidal anti-inflammatory agent (NSAID), and typical CYP 3A inducers in primary cultures of dog hepatocytes.

First, the effect of E 5110, a non-steroidal anti-inflammatory agent (NSAID), on cytochrome P450 subfamilies in dog hepatocyte culture was examined. E 5110 has been shown to cause a drug interaction in dogs and humans via induction of cytochrome P450 3A (CYP 3A). When dog hepatocytes were cultured for 72 h in the presence of 2-30 microM E 5110, the activity levels of ethoxycoumarin O-deethylase (ECOD) and testosterone 6 beta-hydroxylase (6 beta-OH-T) rose dose-dependently. Subsequent Western blot analysis of microsomes from hepatocyte cultures indicated the presence of higher amounts of CYP 2B and 3A proteins than those of the control. Next, the P450 inducing potency of E 5110 was compared with those of phenobarbital, rifampicin, phenytoin and carbamazepine, which induce CYP 3A in human subjects and human hepatocyte cultures. E 5110 was found to be nearly as effective as phenytoin, but less potent than rifampicin, on the basis of 6 beta-OH-T induction.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1995

Expression of the proliferative cell nuclear antigen (PCNA) in adenocarcinoma of the gallbladder, and its relationship to prognosis.

Proliferative cell nuclear antigen (PCNA) has been correlated with degree of differentiation in some tumours, but information on PCNA expression in adenocarcinoma of the gallbladder is currently limited. Therefore, we examined PCNA expression in adenocarcinoma of the gallbladder, and its relationship to prognosis. The expression of PCNA was studied by immunohistochemistry in 70 formalin-fixed, paraffin-embedded specimens of surgically removed adenocarcinomas of the gallbladder. The percentage of stained nuclei was recorded, and the PCNA-labelling index (LI) was expressed as the ratio of labelled nuclei to the total number of nuclei counted. In all histological types, the PCNA-LI in the invasive zone of the tumour was higher than that in the luminal zone of the tumour (p < 0.05). The PCNA-LI showed a stepwise increase with decreasing degrees of differentiation in both the invasive and the luminal zone of the tumour (p < 0.01). In advanced adenocarcinomas, patients whose tumours had a PCNA-LI of less than 35 in the invasive zone had significantly longer survival rates than those with PCNA-LI equal to or greater than 35 (p < 0.01). Multivariate analysis, using the Cox proportional hazards model, indicated that a PCNA-LI > or = 35 in the invasive zone of the tumour was a significantly unfavourable prognostic factor (p = 0.002). The PCNA-LI of routinely processed specimens of adenocarcinoma of the gallbladder may be helpful for the evaluation of cell proliferation and prognosis.

Adenocarcinoma↗
PubMed1995

Chronic toxicity of tar from heavy-duty diesel exhaust following intratracheal instillations to the lungs of hamsters.

Chronic toxicity of tar from heavy-duty diesel exhaust (HD tar) was studied in male Syrian golden hamsters which received 15 mg, 7.5 mg or 1.5 mg of HD tar as the total dosages by intratracheal instillations once a week for 15 weeks. As a control group, hamsters were treated with the 0.1 ml of Tween 60: ethanol: phosphate buffer (pH 6.88, 0.25 M) solution (5.8: 8.7: 100 by volume) once a week in the same manner. The survival rate during the instillation period in the group given 15 mg of HD tar, the high-dose group of HD tar, was the lowest, and the effect was dose-dependent. However, the survival rates during the subsequent observation period showed no marked differences among HD tar treated groups. During their total life span, one papilloma in the larynx was seen in the 44 hamsters in the group given 1.5 mg of HD tar, one papilloma in the larynx was appeared in the 59 hamsters in the group given 1.5 mg of HD tar and one lung adenoma was developed in the 58 hamsters in the control group. There were no tumors in the respiratory tract in the group given 7.5 mg of HD tar. Concerning the histopathological findings of the lung, the incidence of alveolar cell or bronchiolar cell hyperplasia in the group given 1.5 mg of HD tar was significantly higher than that in the control group. From these results, although we could not observe any tumorigenicity or carcinogenic effect of HD tar, it would seem that HD tar caused weak but positive damage to the lungs of hamsters.

Animals↗
PubMed1995

[The reliability and the significance of serum amylase levels in the diagnosis of the pancreatic injury].

To clarify the diagnostic reliability and significance of serum amylase levels (SAL) in the patients with pancreatic injury (PI), we reviewed 67 PIs. The elapsed time between injury and arrival of the hospital (ETAI) in the patients with normal SAL (1.3 +/- 0.2 hours, mean +/- SE) was significantly shorter than those with hyperamylasemia (5.8 +/- 0.9 hours). SAL on arrival significantly correlated to ETAI in the patients with type I (contusion) and type III injury (ductal injury). Among 45 patients who had arrived over 3 hours after injury, none showed normal SAL. Regardless of severity of PIs, one third of the patients showed normal SAL on arrival within 3 hours after injury. Among 23 patients treated conservatively, SAL in 14 patients (60.9%) normalized within 48 hours after injury, and these patients had no complications related to PIs. Three of remaining 9, who had prolonged hyperamylasemia over 48 hours, had pancreatic ductal branch injury or pseudocysts. This frequency was significantly different compared to that in the patients whose SAL normalized within 48 hours after injury. In conclusion, SAL is unreliable and insignificant to diagnose PIs within 3 hours after injury. Not to overlook the PIs serologically, it is important to determine SAL over 3 hours after injury especially in the patients having stable vital signs and to whom PIs are strongly suspected clinically.

Adolescent↗
PubMed1995

Human T-lymphotropic virus type-I, and hepatitis A, B and C viruses in Nepal: a serological survey.

In 1987, 676 blood samples were collected from inhabitants of the Bhadrakali and Kotyang villages in Nepal. The samples were tested for the prevalence of antibody to hepatitis A virus (anti-HAV), hepatitis B surface antigen (HBsAg), antibody to hepatitis B core antigen (anti-HBc), second-generation antibody to hepatitis C virus (anti-HCV) and antibody to human T-lymphotropic virus type-I (anti-HTLV-I). Anti-HAV was present in 99.3% of the people surveyed. The prevalence of anti-HAV reached 100% in the < 25 age group and was as high or only slightly lower in all other age groups. The prevalence of HBsAg was 0.3% and of anti-HBc 7.7%. Anti-HCV was found in 0.1% of the residents. No significant difference by gender or village was noted in the prevalence of anti-HAV, HBsAg, anti-HBc, or anti-HCV. No anti-HTLV-I-positive persons were identified. These data suggest that the prevalence of hepatitis B and C virus infections in Nepal is low in contrast to hepatitis A virus infection, and that human T-lymphotropic type-I infection may be absent in this population.

Adolescent↗
PubMed1995

[Modification of vancomycin nephrotoxicity by other antibiotics in rats].

Vancomycin (VCM) was intravenously administered to rats for 14 days at doses of 150 mg/kg/day and 250 mg/kg/day alone or in combination with 1,000 mg/kg/day of latamoxef (LMOX), flomoxef (FMOX) or cefpirome (CPR) or 250 mg/kg/day of fosfomycin (FOM), and the influences of combined antibiotics on the VCM-induced renal damage were studied. The renal impairment caused by VCM alone was, morphologically, demonstrated mainly as regeneration of tubular epithelium: slight regeneration was observed in a half of rats administered 150 mg/kg/day and slight to extensive regeneration in all the rats administered 250 mg/kg/day. Clinical examinations found apparent increases in urinary LDH and MDH activities in rats administered 250 mg/kg/day, thus showing a good correlation with renal pathological changes. In addition, increase in kidney weight and increase in urinary NAG activity were noted, while changes in plasma urea-N and creatinine were mild, and gamma-GTP activity and protein in urine could not be used as a parameter of the renal impairment. The slight renal impairment as noted in rats administered VCM 150 mg/kg/day alone was not observed at all when LMOX or FMOX was administered concomitantly, and less pronounced even when FOM was administered concomitantly. When CPR was administered concomitantly, the changes were the same as those observed with VCM alone. The renal impairment in rats administered VCM 250 mg/kg/day was apparently less severe when combined with LMOX, FMOX and FOM than that in rats administered VCM alone, and this was supported by apparent reduction of clinical examination values as the parameter of VCM-induced nephrotoxicity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Structure and functions of endotoxin-binding peptides derived from CAP18.

CAP18 (cationic antimicrobial protein, 18kDa) is a 142 amino acid protein originally isolated from rabbit granulocytes using agglutination of LPS-coated erythrocytes as an assay. CAP-18 is composed of an N-terminal domain of unknown function (CAP181-105) and a C-terminal LPS-binding domain (CAP18106-142). Synthetic CAP18106-142 and CAP18106-137, a 32-amino acid peptide resulting from the truncation of 5 amino acids from the C-terminus of CAP18106-142, inhibited LPS-induced tissue factor generation, nitric oxide production and TNF release by macrophages. Mice treated with CAP18106-142 or CAP18106-137 were significantly protected from LPS lethality. Although CAP18106-142 and CAP18106-137 were highly active, other fragments of CAP18106-142, including CAP18110-142 with a truncated N-terminus, did not exhibit LPS-binding and LPS-neutralizing activities. Both peptides had broad anti-microbial activity against both Gram-negative bacteria such as Escherichia coli, Salmonella typhimurium, Klebsiella pneumoniae, Pseudomonas aeruginosa (IC50; 40-100 nM) and Gram-positive bacteria such as Staphylococcus aureus(Methicillin sensitive and resistant strains) and Streptococcus pneumoniae (IC50; 100-200nM). We cloned a CAP18 family protein from human granulocytes. The cloned cDNA encoded 140 amino acid residues. Human CAP18 (CAP181-140) was highly homologous to that of rabbit. A 32- amino-acid C-terminal fragment (CAP18104-135) was shown to bind LPS, inhibit LPS-induced tissue factor generation by murine macrophages, and protect mice from LPS lethality. This peptide exhibited antimicrobial activity against both Gram-negative and Gram-positive bacteria. We hypothesize that CAP18 and the derived peptides bind to LPS and alter the capacity of LPS to initiate disseminated intravascular coagulation. In this regard, CAP may act as host defense protein against infectious diseases, and have therapeutic potential for sepsis and endotoxin shock.

Acute-Phase Proteins↗
PubMed1995

Digital nerve conduction velocity for evaluation of peripheral nerve impairments in vibration syndrome.

In order to evaluate peripheral nerve impairments in vibration syndrome, sensory nerve conduction velocity (SCV) in the digital segment of the median nerve was measured by applying electrical stimulation to the wrist and recording from two pairs of electrodes attached to the middle finger. Fractionated SCVs were also measured in the palm-to-finger, wrist-to-palm, and elbow-to-wrist segments of the median nerve. Subjects were 65 patients with vibration syndrome and 48 healthy controls of similar age. SCVs in the digital nerve segment were significantly slower in the patients than in the controls. Significant slowing was also found in the wrist-to-palm segment. SCVs in the palm-to-finger and elbow-to-wrist segments did not differ between the two groups. Slowed SCVs were most frequently encountered in the digital segment (38% of the patients). The slowing in the wrist-to-palm segment was found in 20% of the patients. Present findings indicate that the digital segment is most frequently affected in vibration-induced neuropathy, and measurement of SCVs in the digital segment would serve to evaluate the peripheral neuropathy in vibration syndrome.

Case-Control Studies↗
PubMed1995

Nerve conduction velocities in the lower extremities among patients with vibration syndrome.

In order to clarify the effect of vibration syndrome (VS) on the peripheral nervous system (PNS) in the lower extremities, 59 patients with VS (age 58.5 +/- 5.1 years) and 49 age-matched controls (age 57.0 +/- 5.1 years) were examined for sensory nerve conduction velocities (SCV) in the sural nerve (SSCV) and the medial plantar nerve (PSCV) in the summer of 1993 and 1994. They had not been suffering from diseases and injuries which might have affected the SCV in the lower extremities. These patients were divided into two subgroups, one with past vibration exposure to chainsaw (N = 22) and the other with past vibration exposure to rock drills and other tools (N = 37). SCVs corrected by skin temperature were subjected to statistical analysis. In PSCV a significant reduction among all patients (40.8 +/- 4.24 m/s, p < 0.01) including two subgroups (chainsaw, 39.7 +/- 4.7 m/s, p < 0.01; rock drill and others, 41.0 +/- 4.6 m/s, p < 0.01) was observed compared with those of the controls (43.2 +/- 4.31 m/s), but there was no significant reduction in SSCV. Significantly more subjects with PSCV below the standard of PSCV (ten percentile value of those of the controls) were observed among all patients (17/59, 28.8%, p < 0.05) including two subgroups (chainsaw, 7/22, 31.8%, p < 0.05; rock drill and others, 10/37, 27.0%, p < 0.05) than in the controls (4/49, 8.2%). These findings suggested that VS affected the PNS function in the lower extremities and that its mechanism was considered to mediate a circulatory disturbance, and to differ from SCV reduction in the finger.

Case-Control Studies↗
PubMed1994

D-myo-inositol 1,4,5-trisphosphate binding domain of phospholipase C-delta 1.

D-myo-Inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) binding domain of phospholipase C-delta 1 (PLC-delta 1) was determined by examining binding activity of the synthetic peptide corresponding to residues 30-43 of PLC-delta 1. The peptide coupled with carrier proteins such as keyhole limpet hemocyanin or bovine serum albumin bound Ins(1,4,5)P3, whereas a scrambled peptide with the same amino acids did not do so. Polyclonal antibody against the peptide was examined to determine whether it would cause inhibition of the Ins(1,4,5)P3 binding to PLC-delta 1. Fab fragment of antibody to the peptide did inhibit binding to PLC-delta 1, in a dose-dependent manner. Thus it seems likely that the region of residues 30-43 of PLC-delta 1 is responsible for the binding of Ins(1,4,5)P3.

Amino Acid Sequence↗
PubMed1994

Molecular characterization of a mouse prostaglandin D receptor and functional expression of the cloned gene.

Prostanoid receptors belong to the family of G protein-coupled receptors with seven transmembrane domains. By taking advantage of nucleotide sequence homology among the prostanoid receptors, we have isolated and identified a cDNA fragment and its gene encoding a mouse prostaglandin (PG) D receptor by reverse transcription polymerase chain reaction and gene cloning. This gene codes for a polypeptide of 357 amino acids, with a calculated molecular weight of 40,012. The deduced amino acid sequence has a high degree of similarity with the mouse PGI receptor and the EP2 subtype of the PGE receptor, which together form a subgroup of the prostanoid receptors. Chinese hamster ovary cells stably expressing the gene showed a single class of binding sites for [#H]PGD2 with a Kd of 40 nM. This binding was displaced by unlabeled ligands in the following order: PGD2 > BW 245C (a PGD agonist) > BW A868C (a PGD antagonist) > STA2 (a thromboxane A2 agonist). PGE2, PGF2 alpha, and iloprost showed little displacement activity at concentrations up to 10 microM. PGD2 and BW 245C also increased cAMP levels in Chinese hamster ovary cells expressing the receptor, in a concentration-dependent manner. BW A868C showed a partial agonist activity in the cAMP assay. Northern blotting analysis with mouse poly(A)+ RNA identified a major mRNA species of 3.5 kb that was most abundantly expressed in the ileum, followed by lung, stomach, and uterus.

Amino Acid Sequence↗