Purification and catalytic properties of a novel acetohexamide-reducing enzyme from rabbit heart

An enzyme catalyzing the metabolic reduction of acetohexamide [4-acetyl-N-(cyclohexyl-carbamoyl)benzenesulfonamide], an oral antidiabetic drug, was purified to homogeneity from the cytosolic fraction of rabbit heart. The molecular mass of the purified enzyme was estimated to be 110 kDa by gel filtration and nondenaturing PAGE and 28 kDa by SDS-PAGE, suggesting that the enzyme is composed of four identical-size subunits. 4-Benzoyl-pyridine and p-nitroacetophenone, typical substrates of carbonyl reductase [EC 1.1.1.184], were not reduced by the enzyme. Of drugs with a ketone group tested, only acetohexamide was a good substrate of the enzyme. the enzyme effectively reduced analogs substituted with various alkyl groups instead of the cyclohexyl group in acetohexamide, although it had little or no ability to reduce analogs substituted with various alkyl groups instead of the methyl group in acetohexamide. The enzyme was inhibited not only by quercetin, a well-known inhibitor of carbonyl reductase, but also by phenobarbital, a potent inhibitor of aldehyde reductase [EC 1.1.1.2]. These results indicate that the enzyme purified from rabbit heart is a novel enzyme responsible for the reduction of acetohexamide and its analogs.

[Intracavitary bacillus Calmette-Guerin therapy for upper tract transitional cell carcinoma]

Four patients with upper urinary tract transitional cell carcinoma were treated with bacillus Calmette-Guerin (BCG) via a percutaneous nephrostomy tube or a retrograde ureteral catheter. A 68-year-old female and an 80-year-old male had carcinoma in situ (CIS) in the left upper urinary tract (cases 1 and 2). A man aged 47 had CIS in the left upper urinary tract, bladder, and prostatic urethra (case 3). CIS in the left upper urinary tract was identified in a woman aged 63 with chronic renal insufficiency (case 4). Two patients (cases 1 and 2) responded to this therapy. In the other two patients nephrectomy was performed due to residual tumor. There were extensive tuberculous granulomas in the kidneys. In one resected kidney (case 4) carcinoma had invaded the renal parenchyma. The reviewed literature showed that BCG perfusion therapy was effective in 71% (27 of 38 renal units) for the upper urinary tract tumors and that there were 5 cases of severe complication, including sepsis in 2, high fever in 2, and ureteral stricture in 1. Based on the fact that the kidney receives a profuse blood supply and that the renal pelvis and ureter have a thin wall, careful management is mandatory to prevent severe adverse effects and insidious tumor progression.

Detection of dilated subarachnoid space around the optic nerve in patients with papilloedema using T2 weighted fast spin echo imaging

Images

Iodine-123 metaiodobenzylguanidine images reflect intense myocardial adrenergic nervous activity in congestive heart failure independent of underlying cause

OBJECTIVES

This study was undertaken to assess myocardial adrenergic activity using iodine-123 metaiodobenzylguanidine (MIBG) imaging in patients with heart failure.

BACKGROUND

In patients with congestive heart failure, adrenergic nerve activity is accelerated. However, whether myocardial adrenergic nerve activity reflects the severity of heart failure and its relation to the underlying cause have not yet been elucidated.

METHODS

Planar MIBG images were obtained from 96 patients with heart failure and compared with images from 9 age-matched healthy subjects. Groups 1 and 2 included 65 patients with heart failure related to impaired myocardial function and whose left ventricular ejection fraction was < 40% (group 1 = 40 patients with dilated cardiomyopathy; group 2 = 25 patients with ischemic cardiomyopathy). Group 3 included 31 patients with heart failure related to a mechanical abnormality and whose left ventricular ejection fraction was > 40% (mitral regurgitation in 16, aortic regurgitation in 9, aortic and mitral regurgitation in 4, ruptured aneurysm of Valsalva in 2). Myocardial uptake of MIBG was calculated as the heart/mediastinal activity ratio. Storage and release of MIBG were calculated as percent myocardial MIBG washout from 15 min to 4 h after isotope injection.

RESULTS

The heart/mediastinal activity ratio in the immediate images (15 min) showed a significant decrease only in patients with severe heart failure (groups 1 and 2). The myocardial washout was accelerated in all three heart failure groups. The level of myocardial washout was related to severity of heart failure and correlated well with New York Heart Association functional classification.

CONCLUSIONS

In severe heart failure associated with cardiomyopathy, norepinephrine uptake is reduced. In addition, myocardial adrenergic nerve activity is accelerated in proportion to severity of heart failure, independent of the underlying cause.

A case of subacute necrotizing fasciitis

We report a 48-year-old woman who developed necrotizing groin fasciitis with insidious onset. Before she visited us, she had been unsuccessfully treated with several kinds of antibiotics by other doctors for one month, because of a small ulcer covered by blackish necrotic tissue. She was referred to us because of high fever, an ulcer on the left labium majus, and a cellulitis-like lesion with severe pain on the lower abdomen. Methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus intermedius, and Bacteroides uniformis were isolated from the wound. After aggressive debridement on the eighth day after admission of the whole indurated area and the fascia of the underlying muscle, healthy granulation tissue covered the defect, and the wound was finally closed with a skin graft Long-term administration of antibiotics along with insufficient and delayed surgical treatment were considered to have caused the full development of this disease.

Felbamate relieves several abnormal pain sensations in rats with an experimental peripheral neuropathy

The antiepileptic drug, felbamate, was tested in a rat model of painful peripheral neuropathy (the chronic constriction injury model). Intraperitoneal doses of 150, 300 and 600 mg/kg were given to animals with established heat-hyperalgesia, mechanohyperalgesia, mechano-allodynia and signs of spontaneous pain (hindpaw guarding). Postinjection tests were conducted 2, 6, 12, 24 and 48 h later. The 150 mg/kg dose had little or no effect on any measure. Significant reductions in all measures of abnormal pain were seen after the 300 and 600 mg/kg doses; relief lasted 2 to 12 h. Side effects were trivial or absent by 2 h postinjection. Felbamate's actions were generally antihyperalgesic and antiallodynic, rather than analgesic, in that the responsiveness of the control (sham-operated) hindpaw was unaffected. We conclude that felbamate suppresses neuropathic pain sensations and that its effectiveness may be due to multiple mechanisms of action. The recently discovered severe side-effect liability of felbamate is likely to preclude its clinical application.

Benefits of arterial reconstruction in claudication

We conducted a midterm follow-up of 150 claudicants who underwent surgical reconstruction by assessing cumulative patency, survival, and palliation (graft patency in live patients) rates. Eighty-nine claudicants (group I) underwent direct (in situ) proximal revascularization, 33 (group II) had indirect (ex situ) proximal revascularization, while 28 (group III) had distal revascularization. The secondary patency rates at 3 years were 97.5% in group I, 97.0% in group II, and 75.0% in group III, respectively. Only one patient with limb graft thrombosis required below-knee amputation. There were 3 perioperative deaths (2 in group I and 1 in group II). The survival rates at 3 years were 86.0% in group I, 69.5% in group II, and 95.8% in group III, respectively. The palliation rates at 3 years were 84.8% in group I, 70.0% in group II, and 77.9% in group III, respectively. These findings indicate the midterm benefits of supra- and infrainguinal arterial reconstructions, and also suggest that the preoperative assessment of risks in individual patients, the selection of the appropriate operative procedure and graft material, and intensive postoperative follow-up and management of any associated disease are all important aspects in the treatment of claudicants.

Strain- and sex-related differences of acetohexamide reductase activities in liver microsomes and cytosol of rats: the Wistar-Imamichi strain lacks the male-specific microsomal enzyme activity

A marked strain-related difference was observed among acetohexamide reductase activities in liver microsomes of male rats. The microsomal enzyme activities in the Fischer-344 (Fischer), Sprague-Dawley (SD) and Wistar strains were 2.58 +/- 0.50, 1.60 +/- 0.44 and 0.79 +/- 0.41 nmol/min/mg protein, respectively. The microsomal enzyme activities in these rat strains were much higher in males than in females, indicating that the microsomal enzyme is a male-specific enzyme. The Wistar-Imamichi (Wistar-IM) strain was found to lack the male-specific microsomal enzyme activity. In Fischer, SD and Wistar strains of testectomized male rats, the microsomal enzyme activities were significantly increased by the treatment with testosterone. However, testosterone treatment was ineffective on the microsomal enzyme activity in the Wistar-IM strain. These results suggest that Wistar-IM rats has a genetic deficiency of the microsomal enzyme. There was no strain-related difference among the cytosolic enzyme activities in male rats. The cytosolic enzyme activities in Fischer and Wistar rats were higher in females than in males.

Stable human T-lymphotropic virus type I carrier rates for 7 years among a teenaged blood donor cohort of 1986 in Kumamoto, Japan

The human T-lymphotropic virus type I (HTLV-I) carrier rates for blood donors in Kumamoto, Kyushu, Japan for 8 years, 1986-1993, are currently available. The data show that 16-19-year-olds in 1986 and 20-29-year-olds in 1993 represent nearly the same cohort, because the median age in both groups is 24.5 years in 1993. Therefore, comparison of the HTLV-I positive rate for the two groups gives an estimate of the change in the rate over 7 years within the cohort. In males, 265 of 22,143 donors (1.20%) were seropositive for HTLV-I among 16-19-year-olds in 1986, and 214 were seropositive among 20,076 (1.07%) donors in 20-29-year-olds in 1993. In females, 203 were seropositive among 20,677 (0.98%) donors in 16-19-year-olds in 1986, and there 154 were seropositive among 18,660 (0.83%) donors in 20-29-year-olds in 1993. Thus, the seropositive rates declined in both sexes. However, the average annual rate of immigration to Kumamoto Prefecture was 2.37%. If seropositive rates for 20-29-year-olds in 1993 are adjusted for the dilution effect due to immigration (under the assumption that all immigrants were HTLV-I negative), the adjusted carrier rate for males is 1.26% and that for females is 0.98%. The adjusted carrier rates for both sexes are almost the same as those for 16-19-year-olds in 1986. This indicates that horizontal transmission was negligible for those in the cohort who were in their early reproductive period. Using all 8 year carrier rates for 16-19-year-olds and 20-29-year-olds, chronological changes of 20-29-year-olds, in the near future was estimated. The best goodness of fit model indicated that the HTLV-I carrier rate will decline exponentially, and that the rate will decrease by 50% approximately every 10 years for both sexes. It is probable that in recent years south-west Japan has lost the conditions that are favorable for HTLV-I endemicity and the virus will be virtually non-endemic within a few generations.

Severity and predicted outcome of postoperative Pseudomonas aeruginosa infections

The severity and predicted outcome of postoperative Pseudomonas aeruginosa (P. aeruginosa) infections (PPAI) was evaluated using a severity scoring system based on a simplification and modification of the APACHE II system. A total of 86 patients in whom P. aeruginosa was isolated from various sources were examined. PPAI developed in 50 patients, resulting in an overall mortality rate of 24%. An increased severity score (SS) correlated with an increased risk of developing PPAI. Thus, PPAI developed in 33% of the patients with an SS of 0-1, in 66.7% of those with an SS of 2-3, and in 100% of those with an SS of 6 or higher. Moreover, the mortality rate of the patients with an initial score of 6 or higher was 50%. The mean (+/- SD) initial severity score was 5.4 +/- 2.9 for survivors and 2.9 +/- 2.6 for nonsurvivors (P < 0.01). In the patients who subsequently died, the SS remained high throughout the clinical course despite therapy, whereas in the survivors the SS decreased progressively, reflecting a favorable clinical course. These results suggest that our severity scoring system was useful for predicting outcome and monitoring the response of PPAI to therapy.

Asterixis and astatic seizures in association with bilateral insular lesions in a patient with viral encephalitis

We report a 48-year-old man who suffered from viral encephalitis and developed involuntary movements of the hands and astatic seizures as sequelae. T2-weighted magnetic resonance imaging of the brain showed high intensity areas in the bilateral insulae. Electroencephalography (EEG) revealed spike and slow wave complexes and high-amplitude slow waves. The involuntary movements of the hands were diagnosed as asterixis by electromyography. Asterixis affected both hands. Administration of sodium valproate aggravated asterixis and EEG findings, but treatment with clonazepam markedly improved these findings and astatic seizures. The present case indicates that insular lesions might be also responsible for the development of asterixis.

Telomerase activity in gastric cancer

Although many genetic alterations have been reported in gastric cancer, it is not known whether all gastric tumors are capable of indefinite proliferative potential, e.g., immortality. The expression of telomerase and stabilization of telomeres are concomitant with the attainment of immortality in tumor cells; thus, the measurement of telomerase activity in clinically obtained tumor samples may provide important information useful both as a diagnostic marker to detect immortal cancer cells in clinical materials and as a prognostic indicator of patient outcome. Telomerase activity was analyzed in 66 primary gastric cancers with the use of a PCR-based assay. The majority of tumors (85%) displayed telomerase activity, but telomerase was undetectable in 10 tumors (15%), 8 of which were early stage tumors. Most of the tumors with telomerase activity were large and of advanced stages, including metastases. Survival rate of patients of tumors with detectable telomerase activity was significantly shorter than that of those without telomerase activity. Alterations of telomere length (reduced/elongated terminal restriction fragments) were detected in 14 of 66 (21%) gastric cancers, and all 14 had telomerase activity. Cellular DNA contents revealed that all 22 aneuploid tumors had detectable telomerase activity. The present results indicate that telomerase activation may be required as a critical step in the multigenetic process of tumorigenesis, and that telomerase is frequently but not always activated as a late event in gastric cancer progression.

Evidence for a short form of alpha 1(IV) as a major polypeptide in bovine lens capsule

The extracts from bovine lens capsule with acetic acid contained, after reduction, three major collagenous polypeptides with M(r) = 180k, 175k, and 160k, which were specifically immuno-stained with anti-type IV collagen polyclonal antibody. The biochemical properties of 180k and 160k polypeptides were akin and were distinct from that of 175k polypeptide [J. Biochem. (1993) 114,358-362]. In the present study, evidence that the 160k and 180k polypeptides from bovine lens capsule both originated from alpha 1(IV) was obtained on the basis of reactivity with a monoclonal antibody that recognizes alpha 1(IV) chain at the collagenous sequence contained in [KGEPGLPGRGFPGFP]. The epitope-bearing sequence was identified from the following three experiments. Pepsin-solubilized polypeptides from human placenta were purified by affinity chromatography on the antibody-coupled column and sequenced. The restriction map of the clones positively reactive with the monoclonal antibody from human placenta cDNA library was superimposed on that of human alpha 1(IV) cDNA at a specific region. Synthetic peptides corresponding to the sequence were assayed for inhibitory activity against the reaction between epitope-bearing pepsin fragments and the antibody. The 180k and 160k polypeptides showed similar intensities in protein staining as well as in immuno-staining with the monoclonal antibody. In contrast, the 175k polypeptide did not react with the monoclonal antibody, indicating that it is a genetically distinct type IV collagen chain, presumably alpha 2(IV) from its abundance. The 160k, a major type IV collagen polypeptide, is a short form of alpha 1(IV) present as a tissue form in bovine lens capsule.

Mac-1 expression and superoxide generation of the peripheral polymorphonuclear leukocyte following gastrectomy and esophagectomy

The aim of this study was to evaluate the characteristics of the polymorphonuclear leukocyte (PMN) function after surgical stress. We investigated Mac-1 expression and superoxide generation by peripheral PMNs and serum granulocyte-colony stimulating factor (G-CSF) concentrations in 15 patients who underwent either gastrectomy (n = 8) or esophagectomy (n = 7). The serum G-CSF rapidly increased within 24 hours after operation. The maximum levels of serum G-CSF in the cases of esophagectomy were about 5-8 fold those of gastrectomy, although the increases in PMN counts within 24 hours of esophagectomy were lower than those after gastrectomy. Mac-1 expression and superoxide generation by PMN counts and serum G-CSF. After esophagectomy, Mac-1 expression on peripheral PMNs remained elevated through the 7th day after operation, while superoxide generation by PMNs in response to PMA declined to below preoperative levels after the 3rd day. These results suggest that, after major surgery such as esophagectomy, there is a discrepancy between Mac-1 expression and superoxide generation by the peripheral PMN despite a high level of serum G-CSF.

[Clinical usefulness of polyamino acid particle agglutination test for detection of anti-HTLV-I antibody]

A new artificial carrier particle agglutination test using polyamino acid (polyamino PA) was developed for anti HTLV-I assay. We carried out the comparative study on anti-HTLV-I among polyamino PA, gelatin PA, EIA and WB methods. All of 76 ATL, 20 HAM/TSP, 53 patients with uveitis and 50 HTLV-I carriers were seropositive and 50 HTLV-I non carriers were seronegative with four methods. Eighteen of 503 patients include autoimmune diseases showed seropositive by polyamino PA and gelatin PA. One of 19 seropositives by EIA was false positive. All of 25 sera showed non-specific reaction by the gelatin PA were clearly negative by the polyamino PA. This is due to the fact that the polyamino acid particle has a greater specific gravity as carrier. The final judgement was got within 45 minutes. It was earlier more 30 minutes than the gelatin PA. The polyamino PA is a simple, rapid, sensitive and specific method. Therefore, it is useful for mass screening and clinical diagnosis.

Mechanism of inhibition of carbonyl reductase from rabbit kidney by phenylbutazone

Phenylbutazone showed significant inhibition against the metabolic reduction of acetohexamide catalyzed by carbonyl reductase purified from rabbit kidney. Thus, the inhibitory effect of phenylbutazone was kinetically examined. Phenylbutazone was a competitive inhibitor for the enzyme with respect to NADPH, whereas it noncompetitively inhibited the enzyme activity with respect to acetohexamide. A fluorescence study revealed that phenylbutazone decreases the binding of NADPH to the free enzyme (apoenzyme). These results suggest that phenylbutazone causes the inhibition of carbonyl reductase by competing with NADPH in its coenzyme-binding domain.

Mechanism of phospholipase D activation induced by prostaglandin D2 in osteoblast-like cells: function of Ca2+/calmodulin

Prostaglandin D2 (PGD2) stimulated the formation of choline in a dose-dependent manner in the range between 10 nM and 10 microM. The effect of PGD2 on the formation of inositol phosphates (EC50 was 20 nM) was more potent than that on the formation of choline (EC50 was 0.5 microM). The formation of choline stimulated by a combination of PGD2 and 12-O-tetradecanoylphorbol-13-acetate (TPA), an activator of protein kinase C, was additive. Staurosporine, an inhibitor for protein kinases, enhanced the PGD2-induced formation of choline, but H-7, another inhibitor for protein kinases, had little effect. PGD2 stimulated Ca2+ influx from extracellular space dose-dependently. The depletion of extracellular Ca2+ by EGTA reduced the PGD2-induced formation of choline. W-7 and trifluoperazine dihydrochloride, antagonists of calmodulin, dose-dependently inhibited the PGD2-induced choline formation. These results strongly suggest that PGD2 activates phospholipase D in a Ca2+/calmodulin dependent manner in osteoblast-like cells, and that protein kinase C is not essential for the PGD2-induced activation of phospholipase D.

Role of melatonin deficiency in the development of scoliosis in pinealectomised chickens

We studied the possible role of melatonin deficiency in experimentally-induced scoliosis. A total of 90 chickens underwent pinealectomy on the third day after hatching: 30 were treated with serotonin, 30 with melatonin and 30 received no therapy (control group). Scoliosis developed in all the control group, in 22 of the serotonin group, and in only 6 of the melatonin group. The six melatonin-treated chickens with scoliosis had less severe spinal deformities than those in the serotonin-treated group. There were lower blood melatonin concentrations in chickens with scoliosis than in those without. Our findings suggest that melatonin deficiency contributes to the aetiology of this experimental scoliosis, probably by interfering with the normally symmetrical growth of the proprioceptive system involving the paraspinal muscles and the spine.

Role of melatonin deficiency in the development of scoliosis in pinealectomised chickens

We studied the possible role of melatonin deficiency in experimentally-induced scoliosis. A total of 90 chickens underwent pinealectomy on the third day after hatching: 30 were treated with serotonin, 30 with melatonin and 30 received no therapy (control group). Scoliosis developed in all the control group, in 22 of the serotonin group, and in only 6 of the melatonin group. The six melatonin-treated chickens with scoliosis had less severe spinal deformities than those in the serotonin-treated group. There were lower blood melatonin concentrations in chickens with scoliosis than in those without. Our findings suggest that melatonin deficiency contributes to the aetiology of this experimental scoliosis, probably by interfering with the normally symmetrical growth of the proprioceptive system involving the paraspinal muscles and the spine.

Influence of aging on acetohexamide reductase activities in liver microsomes and cytosol of male rats

The influence of aging on the reductase activity of acetohexamide, an oral antidiabetic drug with a ketone group, was examined in liver microsomes and cytosol of male rats. Acetohexamide reductase activities in liver microsomes of male rats at 26 and 31 months of age were much lower than that in liver microsomes of male rats at 9 weeks of age. Testectomy markedly decreased acetohexamide reductase activity in liver microsomes of the 9-week old rats and the decreased enzyme activity was significantly increased by testosterone administration. These results indicate, at least in part, that aging decreases the enzyme activity by decreasing the secretion of testosterone from the testes. On the other hand, aging (26 months of age) did not affect acetohexamide reductase activity in liver cytosol of male rats, although the enzyme activity at 31 months of age was slightly but significantly lower than that in liver cytosol of male rats at 9 weeks of age. Testectomy or testosterone administration had no effect on the enzyme activity in liver cytosol of 9-week old male rats.

Combined testosterone treatment in pubertal and adult periods induces male-specific acetohexamide reductase activity in liver microsomes of female rats

The influence of testosterone treatment on acetohexamide reductase activities in liver microsomes and cytosol of female rats was examined. Acetohexamide reductase activity in liver microsomes was much lower in female rats than in male rats. Combined testosterone treatment in pubertal and adult periods induced male-specific acetohexamide reductase activity in liver microsomes of female rats. However, testosterone treatment only during puberty or during adulthood was without effect. Testosterone secreted from the testes during puberty appeared to have a significant effect similar to neonatal imprinting in the induction of acetohexamide reductase activity in liver microsomes of female rats. The combined testosterone treatment, or testosterone treatment only during puberty or during adulthood had no effect on acetohexamide reductase activity in liver cytosol of female rats.

Autonomously replicating sequences identified in transcriptional regulatory regions of human N-myc gene

The regions upstream from the human N-myc gene were examined for both transcription and replication. The plasmids containing several N-myc regions linked to the bacterial chloramphenicol acetyltransferase (CAT) gene were transfected to human neuroblastoma IMR32 cells. The results indicated that the region spanning from the PstI to the BamHI site (N-mycP-B; about 800 bp adjacent to the RNA start site), possessed enhancer activity. Various segments of the N-myc gene, overlapping the transcriptional regulatory regions, were subcloned into pUC19, and the plasmids were transfected to IMR32 cells together with a hygromycin B resistance-expression vector. The transfected cells were cultured in the presence of hygromycin B to establish cell lines resistant to the drug. Among the cell lines obtained, only the cells co-transfected with pN-mycP-B, the region of which contains enhancer activity described above, harboured the replicated pN-mycB-P in an episomal state. The results of BrdU labelling followed by CsCl isopycnic centrifugation suggested that the pN-mycP-B replicated once per cell cycle (in S phase) in concord with the replication of chromosomal DNA. In an in vitro DNA replication system using the nuclear extract from IMR32 cells, pN-mycP-B functioned as an template DNA of replication. Deletions up to 200 bp in the N-mycP-B region did not abolish the replicating activity, regardless of the positions of deletion, but deletions of longer than 300 bp did. These results suggest that the replicating activity of the fragment upstream of the human N-myc gene requires certain length, as well as the specific sequences not yet determined.

Catalytic properties of carbonyl reductase from rabbit liver for analogs of acetohexamide and 4-acetylpyridine

A correlation was observed between the values of specificity constant (kcat/Km) of carbonyl reductase from rabbit liver for acetohexamide analogs and their partition coefficients. This result indicates that the hydrophobicity in straight-chain alkyl groups of acetohexamide analogs plays an important role in the catalytic activity and substrate-binding capacity of the enzyme. Furthermore, the double logarithmic plots of kcat/Km values of the enzyme for 4-acetylpyridine analogs with a straight-chain alkyl group up to five carbon atoms against their partition coefficients gave a straight line. On the other hand, the plots for 4-acetylpyridine analogs with a straight-chain alkyl group over five carbon atoms and with a branched-chain alkyl group were away from the straight line. It is reasonable to postulate that a hydrophobic pocket is located in the substrate-binding domain of the enzyme.