A brief review of epidemiological studies on ischemic heart disease in Japan

The age-adjusted death rate from ischemic heart disease in Japan is the lowest among developed countries and the rates have decreased since 1970. The incidences of myocardial infarction in selected populations ranged between 0.12 and 2.56 per 1,000 for middle-aged males, and between 0.00 and 1.52 per 1,000 for females. The incidences of sudden death within 24 hours were from 0.00 to 1.58 per 1,000 for males and from 0.00 to 0.76 per/1,000 for females. The incidences in Japanese populations appeared to be far below those in Western populations. In the Cox proportional hazard regression model, hypertension and smoking were selected as independent risk factors for myocardial infarction in an agricultural district. It was noteworthy that the level of serum cholesterol was not associated with development of myocardial infarction in rural areas. No positive relation between dietary fat and serum cholesterol was observed in school children, suggesting that growth, sexual maturation and others might be confounding variables between them. The levels of serum cholesterol for females were more affected by menopause than those of blood pressures and body mass index. Although some polymorphisms in selected candidate genes appeared to be associated with some serum lipids and apolipoproteins, the effect of individual RFLP on the inter-individual variations in serum traits was relatively subtle in comparison with that of lifestyle factors.

National Nutrition Survey in Japan

The National Nutrition Survey in Japan has played an important role for nutrition policy in this country, by monitoring nutrition and health status of the Japanese since 1946. During those 50 years, diet of the Japanese has remarkably changed, with the proportion of fat intake in total energy being more than 25% and salt intake gradually decreased. The aim of this survey also has shifted from the policy making for food supplies to monitoring the over intake for prevention of diet-related chronic diseases and health promotion.

[Clinical significance of additional ST segment elevation immediately after successful reperfusion in patients with anterior wall acute myocardial infarction]

The clinical significance of additional ST segment elevation immediately after reperfusion in acute myocardial infarction (AMI) is still unclear. The influence of additional ST elevation on myocardial damage was examined in 62 patients with first anterior AMI. All patients had coronary reflow (thrombolysis in myocardial infarction: TIMI grade III) within 6 hours after the onset of infarction and no subsequent reocclusion for at least 14 days. The patients were classified into two groups: group ST (+), 26 patients with additional ST elevation (> or = 5 mm increase in sigma ST in lead V1-V6) immediately after reperfusion, and group ST(-), 36 patients without additional ST elevation. Myocardial damage was estimated by the number of abnormal Q wave before and 1 hour after reperfusion (nQpre and nQpost. There were no significant differences in the elapsed time, ECG indexes before reperfusion and regional wall motion (RWM: SD/chord; SD = standard deviation) in the acute phase and 14 days after the onset between the two groups. Moreover, within each group the patients were classified into two groups on the basis of RWM 14 days after the onset: group A = RWM < -2.5 in group ST (+) (n = 17); group B = RWM > or = -2.5 in group ST(+) (n = 9); group C = RWM < -2.5 in group ST (-) (n = 14); group D = RWM > or = -2.5 in group ST(-) (n = 22). There were no significant differences in the elapsed time between the four groups. nQpre was highest in group C and was lowest in group D (group A: 2.1, group B: 1.9, group C: 4.1, group D: 1.4), and nQpost was highest in group C and group A, and was lowest in group D (group A: 4.1, group B: 2.7, group C: 4.4, group D: 2.0). There was a significant increase in nQ after reperfusion (nQpost-nQpre) in group A and group B, which was greater in group A than in group B. The increase in sigma ST after reperfusion was greater in group A than in group B. There was no significant increase in nQ after reperfusion in group C and in group D, and both nQpre and nQpost were highest in group C, and lowest in group D. Infarct size was larger in group A and in group C than group B and group D, and there was no significant improvement in RWM in group A and in group C. In conclusion, additional ST elevation immediately after reperfusion seems to occur in patients with not so severe myocardial damage before reperfusion, and may reflect reperfusion injury. Additional ST elevation is not observed in patients with preceding extensive myocardial damage which may be irreversible or not still advanced at the time of reperfusion.

Application of catalyzed signal amplification in immunodetection of gonadotropin subunits in clinically nonfunctioning pituitary adenomas

Pituitary adenomas that are characterized by the absence of a particular clinical syndrome and the absence of excessive hormone secretion have been classified as nonfunctioning adenomas. Recent development of immunohistochemical analysis and hormonal assay have suggested that many of these tumors have function to secret the gonadotropin subunits. A novel procedure biotin amplification in immunohistochemistry, catalyzed signal amplification (CSA) has been reported recently. In this study, the authors applied this new method to tissues from 50 cases of clinically nonfunctioning adenomas. These cases had no evidence of endocrinological signs by hormone secretion. When the CSA system was applied in normal pituitary gland, each of subunits was positive even when the antibody was diluted 1:1,000,000, which is 1,000 folds of standard indirect immunoperoxidase method. Immunohistochemical staining by indirect immunohistochemical method revealed that all 50 adenomas were negative for all the anterior hormones, including growth hormone (GH), prolactin (PRL), adrenocorticotropic hormone (ACTH), beta-subunit of luteinizing hormone (LH beta), follicle-stimulating hormone (FSH beta), thyroid stimulating hormone (TSH beta), and a-subunit of glycoprotein (alpha SU). Using avidin-biotin complex (ABC) method, two cases were positive for FSH beta and four cases were positive for alpha SU, respectively, and the immunopositivities were observed weakly in scattered cells. By CSA system, 26 cases of 50 nonfunctioning adenoma were positive for FSH beta, 16 cases were positive for LH beta, and 29 cases were positive for alpha SU, respectively. The immunoreactivities were clearly observed in cytoplasm of many adenoma cells. This amplification procedure provides a means of greatly increasing the sensitivity of the immunohistochemistry including subunits of glycoproteins that are difficult to detect by previous indirect immunoperoxidase method or ABC method. This amplification procedure provides a great increase in the sensitivity of the immunohistochemistry for the detection of gonadotropin subunits and suggest that significant proportion of the nonfunctioning adenomas are gonadotropin subunit producing adenomas.

Localisation of apoptosis and expression of apoptosis related proteins in the synovium of patients with rheumatoid arthritis

OBJECTIVES

To investigate whether apoptosis occurs in the synovium of rheumatoid arthritis (RA), and the intermediate molecules operating in this process.

METHODS

DNA fragmentation was detected by in situ nick end labelling (ISNEL) in the synovium of patients with RA (n = 11) and control patients with femoral neck fracture (n = 5). The expression of proteins p53, p21WAFI/CIPI, c-myc, proliferating cell nuclear antigen (PCNA), and Bcl-2 was also examined by immunohistochemistry.

RESULTS

ISNEL positive synovial cells with apoptosis specific morphology were detected in extremely limited areas in only two RA synovial tissue specimens. Proteins p53, p21WAFI/CIPI, and c-myc, known inducers of apoptosis or cell cycle arrest or both, were expressed in the sublining cells independent of ISNEL positive cells. PCNA, a marker for cell proliferation, was observed in the synovial lining cells. Bcl-2, an inhibitor of apoptosis, was expressed mainly in infiltrated lymphocytes and in parts of the sublining layer cells of RA; it also did not correspond with ISNEL staining.

CONCLUSIONS

Our findings indicate that RA synovial cells undergo apoptosis in addition to cell proliferation, but the frequency of apoptosis was very low. We suspect that the apoptotic process in the RA synovium may be suppressed by over-expression of Bcl-2. Although expressed proteins p53, p21WAFI/CIPI, and c-myc were present in the RA synovium, these protooncogenes are probably not implicated in the apoptotic process.

Effect of oral administration of protease inhibitor on pancreatic exocrine function in WBN/Kob rats with chronic pancreatitis

The effect of oral administration of protease inhibitor (camostat) on pancreatic morphology and exocrine function (conscious rat model) was investigated using WBN/Kob rats with spontaneous chronic pancreatitis. In nontreated WBN/Kob rats (2-12 months of age), pancreatic fibrosis and parenchymal destruction compatible with human chronic pancreatitis appeared at 3 months and advanced with each month. Pancreatic secretion was markedly impaired at all ages. In WBN/Kob rats fed diets containing camostat (from 2-3 or 4-5 months of age), the pancreas was hypertrophic and did not show any histological appearances compatible with chronic pancreatitis, and moreover, exocrine function was thoroughly restored with increased plasma cholecystokinin concentrations. Oral administration of protease inhibitor has both preventive and therapeutic effects on pancreatic lesions and dysfunction in an animal model of chronic pancreatitis, probably via endogenous cholecystokinin release.

Expression of the major inner capsid protein, VP6, of avian rotavirus in mammalian cells

A gene encoding the major inner capsid protein, VP6, of avian rotavirus was inserted into the eukaryotic expression vector pAX-91 under the control of the SR alpha promoter and was expressed at a high level in simian COS7 cells. The expressed VP6 was indistinguishable in terms of electrophoretic mobility from the corresponding protein synthesized in simian MA104 cells infected with avian rotavirus. Binding assays with a series of monoclonal antibodies (mAbs) that corresponded to four antigenic sites on VP6 of avian rotavirus showed that the antigenic characteristics of the expressed product were identical to those of the native VP6 of avian rotavirus virions. Fiber-like structures that reacted strongly with antiserum against rotavirus were observed in VP6-expressing COS7 cells. Furthermore, an analysis of the tertiary structure of the expressed VP6 protein indicated that it adopts a trimeric configuration, similar to that of the major inner capsid protein of PO-13 virus. From these results, it appears that recombinant VP6 will facilitate studies of the structure and function of authentic VP6, an important protein in avian rotavirus.

Nucleotide sequence of 5'-upstream region and expression of a silkworm gene encoding a new member of the attacin family

A genomic clone encoding a new member of attacin, an insect antibacterial protein, was isolated from a genomic library of the silkworm, Bombyx mori, and the nucleotide sequence of the 5'-upstream region was determined. The region contained Bm 1, a highly repetitive element of B. mori and a lipopolysaccharide (LPS) response element (RE)(NF-kappaB binding site), CAAT box and TATA box. Northern blot analysis showed that the attacin gene expression was rapidly induced by bacterial cell wall components such as LPS from Escherichia coli and peptidoglycan (PG) from Micrococcus luteus, suggesting that attacin plays an important role in an early phase of the self-defense system upon bacterial infection.

Isolation and characterization of a new member of the insect defensin family from a beetle, Allomyrina dichotoma

A new family member of insect defensin, an antibacterial peptide, has been isolated from larvae of a beetle, Allomyrina dichotoma. The peptide consisted of 43 amino acids and 6 cystein residues were conserved in the same position as that of other insect defensins. The new defensin was found to be inducible by bacterial injection. Analysis of the antibacterial spectrum of A. dichotoma defensin indicated that this peptide showed antibacterial activity against Gram-positive bacteria like Staphylococcus aureus and Bacillus subtilis but not against Gram-negative bacteria like Escherichia coli and Pseudomonas aeruginosa, indicating a typical spectrum of the insect defensin family. In addition, A. dichotoma defensin also exhibited antibacterial activity against methicillin-resistant S. aureus (MRSA) isolated from a patient.

Cloning and sequence analysis of the highly expressed melanin-synthesizing gene operon from Streptomyces castaneoglobisporus

Streptomyces castaneoglobisporus HUT6202 overproduces a diffusible melanin-like pigment. An operon, designated mel, containing a gene that encodes tyrosinase, which is involved in the synthesis of melanin pigment, was cloned from the chromosomal DNA of the microorganism into the high-copy plasmid pAK114 and expressed in S. lividans. The tyrosinase activity of the transformed cells was at approximately a 110-fold higher level than that of the same host carrying the plasmid pIJ702, which has the same replication origin as pAK114 and carries the mel operon from S. antibioticus. The sequence analysis of the S. castaneoglobisporus mel operon revealed that an open-reading frame consisting of 378 base pairs(bp), designated ORF378, was found upstream of the tyrosinase gene (TYRC) consisting of 819 bp. In the present study, we constructed a chimeric mel operon consisting of ORF378 from S. castaneoglobisporus and the tyrosinase gene (TYRA) from S. antibioticus. The chimeric mel operon or the S. antibioticus mel operon, which consists of ORF438 and TYRA, expressed the tyrosinase activity in Escherichia coli intracellularly when located under the control of lacZ promoter, and the tyrosinase activity from the former was at a 30-fold higher level than that from the latter. This suggests that the gene contributing to the high expression of the tyrosinase activity in S. castaneoglobisporus is ORF378, rather than TYRC.

Endoscopic transpapillary bile duct biopsy without sphincterotomy for diagnosing biliary strictures: a prospective comparative study with bile and brush cytology

OBJECTIVES

Endoscopic transpapillary bile duct biopsy has a high sensitivity for detection of malignant biliary strictures, but is commonly performed after endoscopic sphincterotomy. We performed transpapillary biopsy without sphincterotomy, using a recently developed, malleable biopsy forceps, and prospectively studied the usefulness of this diagnostic procedure, compared with that of bile and brush cytology.

METHODS

We succeeded in transpapillary biopsy without sphincterotomy in 45 (87%) of 52 patients. In 43 patients with biliary strictures (31 malignant, 12 benign) who successfully underwent all endoscopic samplings by bile aspiration, brushing, and biopsy, the diagnostic value of these three sampling methods was compared.

RESULTS

Transpapillary biopsy (81%) had a significantly higher level of sensitivity for malignancy than bile (32%) and brush (48%) cytology. Transpapillary biopsy was more sensitive for bile duct cancer (88%) than for pancreatic cancer (71%), as were cytology techniques. No false positives were found in any of the three sampling methods. No complications accompanied the endoscopic procedures.

CONCLUSIONS

Transpapillary bile duct biopsy without sphincterotomy is a simple, safe, and effective technique for diagnosing biliary stricture. We recommend that this technique be performed routinely at initial endoscopic retrograde cholangiopancreatography for patients with a stricture or filling defect of the extrahepatic bile duct.

[A case of mitochondrial encephalomyopathy (MELAS)]

Mitochondrial encephalomyopathy is a hereditary syndrome showing impairment of muscle and the central nervous system. In this disorder, the following three syndromes have been identified on the basis of characteristic symptoms: Kearns-Sayre syndrome (KSS), mitochondrial encephalomyopathy with lactic acidosis, and stroke-like episodes (MELAS), and myotonic epilepsy with ragged-red fibers (MERRF). In this report, we describe a case of mitochondrial encephalomyopathy with renal disease. A 25-year-old man was referred to our hospital in May, 1992 for evaluation of long-standing proteinuria. He had a small stature, exotropia and no pretibial edema. No mental retardation was observed. Urinary protein excretion was 2.0 g/day and urine sugar was negative. Laboratory examination revealed a serum urea nitrogen 19 mg/dl, and a creatinine value of 1.5 mg/dl. Creatinine clearance was 45.8 ml/min. His serum and spinal fluid lactate value were elevated. Biopsied muscle showed an absence of ragged-red fibers, and the presence of an A-to-G point mutation at nucleotide pari 3243 in the mitochondrial tRNA(Leu(UUR)) in peripheral blood leucocytes. He was thought to have MELAS. On the renal biopsy specimens, light microscopic examinations showed minor glomerular abnormalities with two glomerular collapses and tubulo-interstitial damage. Electron microscopic examinations showed partial thickening of the glomerular basement membrane. We report here this rare case of MELAS with renal disease, and also review seventeen cases of mitochondrial encephalopathy associated with renal disease. The existence of a relationship between mitochondrial disorder and renal damage remains obscure.

[Use of cortical SEP for the prediction of neurological prognosis after cardiopulmonary resuscitation]

The improved technique of cardiopulmonary resuscitation (CPR) resulted in survival of many patients who had experienced cardiopulmonary arrest (CPA). However, when the recovery of brain function is poor, patients suffer from severe neurological sequelae, including persistent vegetative state. There have been no conclusive methods to predict the outcome of anoxic encephalopathy after CPR. Madl et al (1993) recorded cortical SEP over the parietal scalp electrodes after bilateral median nerve stimulation at the wrists in anoxic patients experiencing CPR. Their results indicated that the median SEP is useful for the early prediction of neurological prognosis after CPR. We studied short and long latency cortical SEPs evoked by the left median nerve stimulation in 18 consecutive anoxic patients within 48 hours after CPR. The absence of N20, N35, P45 indicated mortality of 86.4% (100% in Madl's results). Preserved N60 peak indicated the recovery of consciousness, while Madl's results showed that patients did not regain consciousness when the N60 latency was longer than 121 ms. Neurological prognosis showed the significant correlation with N20, P25 amplitude and not with amplitude ratio (N20 P25/P15 N20). Reduced amplitude of N20 P25 was consistent with the high score of GOS. N20 P25 was greater than 3.7 microV in all patients who regained consciousness. Recording of cortical SEP within 48 hours after CPR was useful for the prediction of neurological outcome.

Restoration of alpha v beta 5 integrin expression in neoplastic keratinocytes results in increased capacity for terminal differentiation and suppression of anchorage-independent growth

Loss of expression of specific integrins is a feature of poorly differentiated oral squamous cell carcinomas (SCCs) and cell lines derived from them. In order to test whether there is a direct link between loss of integrins and abnormal keratinocyte growth and differentiation, we 'repaired' an SCC line, H357, by transfection of its missing integrin subunit, alpha v. We analysed seven independent alpha v-expressing clones and compared them with four empty vector controls and with the parental cell line. alpha v was expressed on the cell surface as a functional alpha v beta 5 heterodimer. The parental cells expressed beta 5 mRNA and introduction of alpha v had no effect on beta 5 mRNA levels nor on cell surface levels of any other integrins examined. Introduction of alpha v had no consistent effect on the growth rate of cells on tissue culture plastic. However, anchorage-independent growth was strongly suppressed and the alpha v-transfectants showed an increased capacity for terminal differentiation, as assayed by expression of involucrin. These results are consistent with the known role of integrins in regulating keratinocyte terminal differentiation and suggest that integrin loss may be directly responsible for the abnormal behaviour of keratinocytes in a subset of oral SCCs.

Successful erythropoietin treatment for severe anemia in nephrotic syndrome without renal dysfunction

A 62-year-old woman presented with nephrotic syndrome and severe anemia although the renal function was not impaired. Renal biopsy revealed the histology of membranoproliferative glomerulonephritis, and the proteinuria was resistant to steroid therapy. Iron deficiency, bleeding and other causes of anemia were ruled out, however, her serum erythropoietin level was inappropriately low. The anemia was rapidly corrected by administration of recombinant human erythropoietin. It is suggested that inappropriately low erythropoietin level, in part at least, accounts for the anemia in nephrotic syndrome. It is proposed that erythropoietin therapy should be taken into consideration for severe anemia in nephrotic syndrome even when the renal function is not impaired.

Protective effect of vitamin E on chromium (VI)-induced cytotoxicity and lipid peroxidation in primary cultures of rat hepatocytes

Pretreatment of primary cultures of rat hepatocytes with alpha-tocopherol succinate (vitamin E) for 20 h prior to exposure to K2Cr2O7 resulted in a marked decrease of chromium (VI)-induced cytotoxicity, as evaluated by the leakage of lactate dehydrogenase, without affecting cellular uptake and the subcellular distribution of chromium. The levels of chromium (VI)-induced lipid peroxidation, as monitored by malondialdehyde formation, were also inhibited by pretreatment with the vitamin. Pretreatment with vitamin E normalized the levels of nonenzymatic antioxidants such as glutathione and vitamin C suppressed by dichromate, and caused a distinct accumulation of vitamin E in hepatocytes. However, vitamin E pretreatment did not affect the activities of enzymatic antioxidants including glutathione reductase, superoxide dismutase, and catalase suppressed by dichromate. These results indicate that the protective effect of vitamin E against chromium (VI)-induced cytotoxicity as well as lipid peroxidation, may be associated more with the level of nonenzymatic antioxidants than the activity of enzymatic antioxidants.

Formation of paramagnetic chromium in liver of mice treated with dichromate (VI)

The formation of paramagnetic chromium in the liver of male mice dosed with K2Cr2O7 (10, 20, and 40 mg Cr/kg) by a single ip injection was investigated by electron spin resonance (ESR) spectrometry. Both Cr(V) and Cr(III) complexes were detected in the mice livers at 15 min to 12 hr after Cr(VI) injection. The time course (15 min-12 hr) for the formation of paramagnetic Cr revealed that the hepatic levels of Cr(V) complexes decreased quickly during the first hour but decreased more slowly over the next 11 hr. However, in contrast to Cr(V), Cr(III) complexes appeared to persist for 12 hr after Cr(VI) treatment based on figures of Cr(III) signal. Thus, Cr(III) may be the ultimate form following reduction of Cr(VI) in liver. The total Cr content in liver of mice dosed with dichromate was also increased in a dose-dependent fashion (10-40 mg Cr/kg). However, Cr content in liver remained at similar levels for 15 min-6 hr, and slightly decreased at 12 hr after Cr(VI) injection. Under the same experimental conditions, hepatotoxicity, as estimated by the increase of serum ornithine carbamyl transferase activity, appeared at 3 hr after 20 and 40 mg Cr/kg of Cr(VI) injection, while 10 mg Cr/kg of Cr(VI) produced no hepatotoxicity even at 12 hr. Predosing with phenobarbital, which increased the hepatic levels of cytochrome P450, resulted in a decrease of the levels of Cr(V) and in a small increase of Cr content, without affecting Cr(VI) hepatotoxicity. On the other hand, pretreatment with buthionine sulfoximine, which depleted hepatic glutathione (GSH) levels, caused a decrease of Cr(VI) hepatotoxicity, but the levels of Cr(V) and Cr in the liver remained unchanged. These results demonstrated that in vivo formation of paramagnetic Cr, in particular Cr(V), in liver of mice is clearly detected and quantified by ESR spectrometry and that hepatic levels of cytochrome P450 and GSH are associated with the induction of biological effects by Cr(VI) in liver in vivo. The results also suggested that the formation of Cr(V) was not the only mechanism involved in the induction of hepatotoxicity by Cr(VI) compounds.

Human pancreatic phospholipase A2 stimulates the growth of human pancreatic cancer cell line

Phospholipase A2 (PLA2) from human pancreas, designated hPLA2-I, functions as a digestive enzyme. Interestingly, the present study demonstrated that the mature form of hPLA2-I stimulated the growth of a human pancreatic cancer cell line MIAPaCa-2, whereas the pro-form was ineffective. PLA2s from Laticauda semifasciata fraction I, Crotalus adamanteus venom, Streptomyces violaceoruber and bee venom, showed no proliferative effect to the growth of MIAPaCa-2. The Scatchard plot analysis revealed that the MIAPaCa-2 cell had a specific binding site for the mature hPLA2-I. The equilibrium binding constant (Kd) and the maximum binding capacity (Bmax) were 2.6 nM and 0.4 fmol/10(6) cells, respectively. These results suggest that the mature hPLA2-I, but not the pro-form, may function as a growth factor of pancreas carcinoma via the specific binding site.

[Histological studies on postnatal development of the musk gland in house musk shrews (Suncus murinus)]

The development of the musk gland in house musk shrews aged 0 to 21 days was studied lectin histochemically. On about 3 days of age, the musk gland could be discriminated from surrounding skin. This organ developed markedly on days 3 to 7, and its development continued to 21 days of age. Histologically, on day 1, the bulges that should develop into musk glands were identified in the vicinity of hair germs. On days 3 to 7, these bulges developed markedly, and on day 21 their structure revealed almost the same morphology with that in mature musk glands. We used 7 lectins; ConA, RCA I, PNA, SBA, UEA-I, DBA, and WGA. On day 1, 6 lectins except for WGA labelled the cell of the musk gland. WGA began to label it on day 3. Until 7 days of age, lectins bound to only the cytoplasm of the cell of musk glands. On days 12, however, PNA and UEA-1 labelled the cell membrane equally, and RCA I labeled it on day 21.

Nitric oxide synthase in cerebral ischemia. Possible contribution of nitric oxide synthase activation in brain microvessels to cerebral ischemic injury

The results of our continuing studies on the role of nitric oxide (NO) in cellular mechanisms of ischemic brain damage as well as related reports from other laboratories are summarized in this paper. Repetitive ip administration of NG-nitro-L-arginine (L-NNA), a NO synthase (NOS) inhibitor, protected against neuronal necrosis in the gerbil hippocampal CA1 field after transient forebrain ischemia with a bell-shaped response curve, the optimal dose being 3 mg/kg. Repeated ip administration of L-NNA also mitigated rat brain edema or infarction following permanent and transient middle cerebral artery (MCA) occlusion with a U-shaped response. The significantly ameliorative dose-range and optimal dose were 0.01-1 mg/kg and 0.03 mg/kg, respectively. Studies using a NO-sensitive microelectrode revealed that NO concentration in the affected hemisphere was remarkably increased by 15-45 min and subsequently by 1.5-4 h after MCA occlusion. Restoration of blood flow after 2 h-MCA occlusion resulted in enhanced NO production by 1-2 h after reperfusion. Administration of L-NNA (1 mg/kg, ip) diminished the increments in NO production during ischemia and reperfusion, leading to a remarkable reduction in infarct volume. In brain microvessels obtained from the affected hemisphere, Ca(2+)-dependent constitutive NOS (cNOS) was activated significantly at 15 min, and Ca(2+)-independent inducible NOS (iNOS) was activated invariably at 4 h and 24 h after MCA occlusion. Two hour reperfusion following 2 h-MCA occlusion caused more than fivefold increases in cNOS activity with no apparent alterations in iNOS activity. Thus, we report here based on available evidence that there is good reason to think that NOS activation in brain microvessels may play a role in the cellular mechanisms underlying ischemic brain injury.

Bacillopeptins, new cyclic lipopeptide antibiotics from Bacillus subtilis FR-2

Bacilopeptins, new iturin-group antifungal antibiotics, were isolated from the culture broth of Bacillus subtilis FR-2 obtained from the rhizosphere of garlic suffering from the basal rot caused by Fusarium oxysporum. Their structures were elucidated to be cyclic lipopeptides similar to bacillomycin L by NMR and mass spectral studies coupled with amino acid analysis. The absolute configuration of each amino acid residue was determined by chiral HPLC.

Bleomycin-induced beta-lactamase overexpression in Escherichia coli carrying a bleomycin-resistance gene from Streptomyces verticillus and its application to screen bleomycin analogues

A bleomycin-resistance gene, designated blmA, has been cloned from bleomycin-producing Streptomyces verticillus by Sugiyama et al. (Gene 151 (1994) 11-16). The present study shows that Escherichia coli harboring the blmA-carrying pUC plasmid overproduced beta-lactamase, encoded by an ampicillin-resistance gene on the plasmid, when cultured in the presence of bleomycin, which suggests that bleomycin may act as an inducer (or an activator) for the expression of the specific gene in the presence of blmA. We constructed a vector, designated pMAB50, which senses bleomycin and produces a pigment, using blmA and a Streptomyces tyrosinase gene located under the control of beta-lactamase promoter: E. coli harboring pMAB50 produced the melanin pigment in the presence of bleomycin-type antibiotics, suggesting that the transformed E. coli can be employed as a reporter organism to screen bleomycin analogues.