Variant forms of glucokinase gene in Japanese patients with late-onset type 2 diabetes

We have applied the technique of single-strand conformation polymorphism analysis to detect mutations of the glucokinase gene in 50 Japanese patients with late-onset type 2 diabetes and in 50 normal Japanese subjects. Out of the 50 patients with late-onset type 2 diabetes, we observed three kinds of variant patterns: one in exon 1b, one in exon 4, and one in exon 5. The incidence of these patterns was one in exon 1b, two in exon 4 and one in exon 5. Direct sequencing of exon 1b and exon 5 revealed mutations in intron areas at the 12th nucleotide downstream from the 5' splice points in two cases. Direct sequencing of exon 4 revealed a heterozygous silent mutation, CCC[Pro]-->CCG[Pro] at codon 145. In contrast, 50 normal Japanese subjects showed no variant patterns in any exons. Our results showed that although 8% (4 out of 50) of Japanese patients with late-onset type 2 diabetes have variant forms of the glucokinase gene, none is expected to cause apparent qualitative changes in glucokinase. We think that the frequency of mutations of the glucokinase gene which could cause qualitative change is very low in Japanese patients with late-onset type 2 diabetes.

Multiple pulmonary hamartomas: report of a case

Among lung tumors, multiple hamartomas are uncommon while multiple chondromatous hamartomas are extremely rare, with only 12 cases having been previously reported. A case of multiple pulmonary chondromatous hamartomas in a 58-year-old Japanese man who has been followed up for 28 years is herein presented.

Analysis of clonality by amplification of short tandem repeats. Carcinomas of the female reproductive tract

The clonal composition of cancers of the female reproductive tract was evaluated by analysis of patterns of X-chromosome inactivation. Using DNA extracted from frozen tissues or paraffin-embedded archival specimens as template, polymerase chain reaction (PCR) was performed to generate amplified DNA fragments of exon 1 of the X-linked androgen receptor gene, which contains a highly polymorphic trinucleotide repeat. Predigestion of tumor DNA with methylation-sensitive restriction endonuclease Hha I or Hpa II permitted selective PCR amplification from the methylated (uncleaved) allele. Of a total of 54 tumors analyzed, 50 cases showed heterozygosity (93%) and were therefore informative for clonal analysis. Monoclonal composition of the tumors was suggested in a total of 49 of 50 cases, including 12 adenocarcinomas of the uterine endometrium, 13 squamous cell carcinomas of the uterine cervix, 6 adenocarcinomas of the uterine endocervix, and 18 epithelial tumors of the ovary. However, polyclonal composition was observed in one mucinous carcinoma of the ovary, in which we previously showed that both GGT-->GAT and GGT-->GTT mutations are present in > 20% of total K-ras copies in the tissue. Our studies demonstrate the utility of PCR amplification of highly polymorphic repetitive sequences for analysis of patterns of X-chromosome inactivation. This approach is practical for the analysis of clonal cell composition in a high proportion of both formalin-fixed and frozen archival tissues.

Effect of successful angioplasty following thrombolysis on infarct size and left ventricular function

The role of the angioplasty following thrombolysis in acute myocardial infarction has been discussed in several studies, however the effect of successful angioplasty on infarct size and left ventricular function has not been properly evaluated. Successful reperfusion was achieved in 79 out of 104 patients with primary anterior acute myocardial infarction. These patients were classified as follows, according to the type of intervention during the acute phase: 50 patients in which thrombolysis was successful (the thrombolysis group); 12 patients who underwent successful immediate angioplasty following successful thrombolysis (the immediate angioplasty group); and 17 patients in which rescue angioplasty was successful (the rescue angioplasty group). The 25 patients whose infarct-related vessels were not reperfused after intervention were classified as the non-reperfused group. Infarct size, evaluated as defect volume by T1-201 SPECT, 1 month after the onset, was 840 +/- 154 units (mean +/- S.D.) in the immediate angioplasty group and was similar to that in the thrombolysis group (948 +/- 88 units), but significantly smaller than in the non-reperfused group (1759 +/- 108 units). There were no significant differences in left ventricular function in the immediate angioplasty group and the thrombolysis group. Successful rescue angioplasty did not have any beneficial effect on left ventricular functions or infarct size, when compared with the failed thrombolytic group (1105 +/- 169 units vs. 1617 +/- 169 units). End-diastolic volume (52 +/- 3 ml/m2) in the successful rescue angioplasty group, however, was significantly smaller than in the failed thrombolysis group (67 +/- 3 ml/m2).(ABSTRACT TRUNCATED AT 250 WORDS)

The role of GABA in the central regulation of AVP and ANP release and blood pressure due to angiotensin and carbachol, and central GABA release due to blood pressure changes

To assess whether GABA given intracerebroventricularly (i.c.v.) affects vasopressin (AVP) and atrial natriuretic peptide (ANP) release and changes in blood pressure in response to i.c.v. angiotensin (AT II) and carbachol (CB), or whether changes in blood pressure affect GABA release in the brain, experiments were carried out. In experiment I (Ex I), GABA (100 micrograms) with AT II (50 ng) or CB (25 ng) was i.c.v. administered in conscious rats (n = 12). The same dose of AT II or CB alone also was administered without GABA (n = 12). In experiment II (Ex II), AT II (100 ng/kg per min) or nitropuruside (NP, 10 micrograms/kg per min) was intravenously (i.v.) infused and GABA release in the area adjacent to the paraventricular nucleus was determined, using the microdialysis method, in conscious rats (n = 12). In the experiments, mean arterial blood pressure (MABP), heart rate (HR), plasma AVP and/or ANP and plasma Na+ and K+ levels were measured. In Ex I, i.c.v. AT II increased plasma AVP and MABP without changes in HR and plasma ANP, but i.c.v. GABA never affected these responses. Icv CB also increased plasma AVP and MABP with decreased HR, but did not affect plasma ANP. Icv GABA abolished bradycardiac responses, but did not affect the others. In Ex II, the pressor response to i.v. AT II increased GABA release without apparent decreases in plasma AVP. However, the depressor response to NP produced decreases in GABA release with increased plasma AVP. These results shows that i.c.v. GABA did not affect AVP and pressor responses to i.c.v. AT II and CB, but changes in blood pressure modulates GABA release in the brain with changes in plasma AVP.

Presence of membrane-bound proteinases that preferentially degrade oxidatively damaged erythrocyte membrane proteins as secondary antioxidant defense

Human erythrocytes were oxidized with xanthine/xanthine oxidase/ferric ion or ADP/ferric ion at 37 degrees C for several hours. Band 3 protein and spectrin of the oxidized cells were found to be significantly modified as analyzed by radiolabeling with tritiated borohydride. Sodium dodecylsulfate-polyacrylamide gel electrophoresis of the xanthine/xanthine oxidase/ferric iron-oxidized cells and subsequent immunoblotting with anti band 3 protein showed that band 3 protein was fragmented into smaller molecular-weight fragments. When the cell membrane obtained from the oxidized cells were incubated at pH 7.4 and 37 degrees C for several hours in the presence of alpha-tocopherol, extensive degradation of band 3 protein and spectrin was observed. Band 3 protein was found to be most susceptible to the degradation. Degradation of band 3 protein was also observed after similar incubation of the membrane from the ADP/ferric ion-oxidized cells. Membrane-bound serine- and metalloproteinases were responsible for the degradation of band 3 protein, because the degradation was remarkably inhibited by diisopropyl fluorophosphate and phenylmethylsulfonyl fluoride, and partially by ethylenediaminetetraacetic acid. Hence, the membrane proteins became susceptible to membrane-bound proteinases by oxidative stress. This observation suggests that these membrane-bound proteinases exist to remove oxidatively damaged proteins from the cell membrane.

DNA-binding characterization of a novel anti-tumour benzo[a]phenazine derivative NC-182: spectroscopic and viscometric studies

NC-182 is a novel anti-tumour compound having a benzo[a]phenazine ring. Fluorescence, absorption and c.d. spectroscopy, as well as viscometric titrations, were systematically performed to investigate the interaction mode of this drug with DNA and its effect on DNA conformation, based on comparative measurements with distamycin (DNA minor-groove binder) and daunomycin (DNA-base intercalator). NC-182 was found to be a potent intercalator of DNA, especially the B-form DNA, although no specificity was observed against the base-pair. The binding of NC-182 to B-DNA behaves biphasically, depending on the molar ratio (r) of drug to DNA: NC-182 acts to render the B-form structure rigid at relatively low r value and to promote the transformation of B- to non-B forms at high r values. It was also shown that NC-182 promotes the unwinding of Z-form DNA to B-form. Viscometric, u.v. 'melting' and c.d. experiments further showed that (1) the DNA duplex structure is thermally stabilized by intercalation with NC-182 and (2) the intercalation of NC-182 into a poly(dA).2poly(dT) DNA structure thermally stabilizes the triplex structure, resulting in a melting point close to that of the duplex structure; the melting curves of triplex and duplex structures coincide at r > 0.06. These observations make a significant contribution to our understanding of the biological properties of this novel benzo[a]phenazine derivative, a new anti-tumour tumour agent against multidrug-resistant and sensitive tumours.

Vagally mediated heart rate recovery after exercise is accelerated in athletes but blunted in patients with chronic heart failure

OBJECTIVES

Vagally mediated heart rate recovery after exercise was assessed in patients with chronic heart failure and in well trained athletes by analyzing the postexercise heart rate decay.

BACKGROUND

Vagal reactivation is an important cardiac deceleration mechanism after exercise. However, alterations of this mechanism under pathologic conditions have not been characterized because of the lack of a specific index.

METHODS

To find a vagally mediated component of heart rate recovery, the time constants of the beat-by-beat heart rate decay for the first 30 s (T30) and the first 120 s (T120) after exercise were obtained at six levels of exercise in eight normal volunteers: 1) at maximal exercise, 2) at anaerobic threshold, 3) at anaerobic threshold with propranolol administration, 4) at anaerobic threshold with atropine administration, 5) at anaerobic threshold with concomitant administration of both drugs, and 6) at 50% of anaerobic threshold. To investigate the effects of heart failure and endurance training on vagally mediated heart rate recovery, T30 and T120 at anaerobic threshold were obtained in 20 patients with chronic heart failure and in 9 cross-country skiers.

RESULTS

In normal volunteers, T30 and T120 were markedly prolonged by atropine administration, indicating that both time constants are mediated by vagal reactivation. Moreover, T30 was almost independent of the exercise intensity and sympathetic blockade, whereas T120 was affected by sympathetic nerve activity and exercise work load. These results indicate that T30 is mediated primarily by vagal reactivation, independent of sympathetic withdrawal, and is significantly smaller in athletes (p < 0.01) and significantly larger in patients with chronic heart failure (p < 0.01) than that in respective age-matched normal control subjects.

CONCLUSIONS

The T30 value could be a specific index for vagally mediated heart rate recovery. Vagally mediated heart rate recovery after exercise is accelerated in well trained athletes but blunted in patients with chronic heart failure.

Molecular cloning and chromosomal assignment of the mouse C-type natriuretic peptide (CNP) gene (Nppc): comparison with the human CNP gene (NPPC)

The mouse C-type natriuretic peptide (CNP) genomic fragment was isolated from a mouse genomic DNA library. The mouse CNP gene is composed of at least two exons and one intron. The 5'-flanking region contains an array of cis-acting regulatory elements and a dinucleotide CA repeat (microsatellite). Analysis of the deduced amino acid sequences revealed that mouse preproCNP is a 126-amino-acid peptide and that its C-terminal 22-residue peptide preceded by Lys-Lys is identical to porcine, rat, and human CNPs. On the basis of the polymerase chain reaction-analyzed microsatellite length polymorphisms among recombinant inbred strains of mice, the CNP gene (Nppc) was assigned to mouse chromosome 1. Furthermore, the human CNP 5'-flanking region was extended for sequencing, and comparison of the mouse and human CNP genomic sequences revealed regions of conservation and diversity. Using somatic hybrid cell methodology, the CNP gene (NPPC) was assigned to human chromosome 2. The present study has added another locus to the conserved syntenic group in mice and humans.

A comparative ESR study of some paramagnetic materials as probes for the noninvasive measurement of dissolved oxygen in biological systems

The ESR properties of three types of paramagnetic material, active charcoal, fusinite and a stable nitroxide radical 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPONE), were examined in order to evaluate their suitability as probes to measure dissolved intra- and extra-cellular oxygen. Although, with changes in oxygen concentration, a greater change in the linewidth of ESR signals was observed with fusinite or active charcoal, it took a long time (15 min for active charcoal and more than 6 h for fusinite) for equilibrium to be achieved. On the other hand, equilibrium was reached very rapidly in the case of the TEMPONE spectra although the sensitivity to changes in oxygen concentration was only moderate. Furthermore, since lipid bilayers are permeable to TEMPONE, this compound can be used to measure intracellular oxygen concentration when employed in combination with membrane-impermeable spin-broadening reagents which act on ESR signals arising from extracellular probes. A perdeuterated derivative of TEMPONE is useful in that it gives a greater signal-to-noise ratio and greater sensitivity to changes in oxygen concentration. In conclusion, active charcoal is suitable as a probe for extracellular oxygen in a system where changes are slow, while nitroxide is a versatile probe for measuring rapidly changing intra- and extra-cellular oxygen concentrations.

Immunohistochemical analysis of p53 in gynecologic tumors

Immunohistochemical staining for the p53 protein was performed in microwave-fixed, paraffin-embedded sections of normal, premalignant and malignant tissues of the female genital tract using a monoclonal antibody, PAb 1801. No staining was detected in normal and premalignant tissues, whereas nuclear staining of cancer cells was observed in 12 (22%) of 55 cervical squamous cell carcinomas, 4 (25%) of 16 cervical adenocarcinomas, 37 (42%) of 88 endometrial carcinomas, 23 (38%) of 60 ovarian adenocarcinomas, and 6 (100%) of 6 squamous cell carcinomas arising in dermoid cysts. Of interest, 1 of 7 endometrial cancers with concomitant atypical hyperplasia showed weak nuclear staining in a few atypical hyperplastic glands in addition to the cancerous lesions. Although staining was associated with cancers having a high histologic grade and serous papillary adenocarcinomas of the endometrium, it did not correlate with invasion, metastasis, or clinical stage. Comparison of the staining patterns with molecular analysis of mutations in the p53 gene showed the expected correlation of nuclear staining with missense mutations but not with nonsense mutations, which consistuted one third of all mutations found in this series. In addition, cytoplasmic staining did not predict mutation.

[An epidemiological study of penicillin-resistant Streptococcus pneumoniae in Japan]

In order to investigate penicillin resistance (Pcr) in Streptococcus pneumoniae from clinical sources in Japan, a total 1,127 strains of S. pneumoniae was collected at random from 36 institutions participating to "Working group for Pcr S. pneumoniae" around the country in 1993-1994. These strains were isolated more frequently from sputum (38.2%), throat (31.4%), nasal discharge (16.4%), and otorrhea (5.7%). A small number of isolates from blood (19 strains; 1.8%), cerebrospinal fluid (11 strains; 1.0%), and pleural fluid (2 strains; 0.2%) were included respectively. Patients from whom S. pneumoniae was isolated have mostly been associated with children < or = 12 years of age and adults 60 < or = years olds. These isolates were tested for susceptibility to penicillin G, ampicillin, oxacillin, cefixime, cefdinir, imipenem, panipenem, erythromycin, clindamycin, minocycline, and vancomycin by an agar dilution method using Mueller Hinton agar supplemented with 10% sheep blood. Strains with the MICs > or = 0.125 micrograms/ml for penicillin G were defined as a Pc resistance. Of the 1,127 strains, 471 strains (41.8%) were identified as a Pc resistance. Pcr S. pneumoniae were almost resistant to other beta-lactams, including ampicillin, oxacillin, ceftizoxime, cefixime, cefdinir. Although, the MICs of imipenem and panipenem ragned from 0.004-2.0 micrograms/ml with 2 peaks distributions, these antibiotics inhibited the growth of most of Pcr S. pneumoniae at the lowest concentrations of < or = 0.5 microgram/ml. Only vancomycin resistant strain was not detected in these isolates. Most of the Pcr strains were simultaneously resistant to macrolides and minocycline. Further more, isolation frequencies of Pcr S. pneumoniae in west Japan, were relatively high compared with those of east Japan.

Lysine deficient diet and lysine replacement affect food directed operant behavior

As a test for specific hunger for amino acids with the goal of identifying brain regions which might mediate motivation to alleviate L-lysine (Lys) deficiency, rats were trained to lever press to receive complete diet. Rats were given Lys deficient (Lys-def) diet ad lib. Intraperitoneal (IP) injection of Lys, 2 h before the test session, inhibited lever pressing. Lys injected animals pressed at nearly the same low rate as did animals fed ad lib complete diet, although the response of saline injected animals was also partially decreased. Next, osmotic minipumps were implanted IP and animals given Lys-def diet ad lib. Chronic Lys infusion also strongly inhibited lever pressing. Rats allowed ad lib access to Lys to drink drank significantly more Lys than when given complete diet. Lys chronically infused by minipump into the lateral hypothalamus, also inhibited pressing by rats given Lys-def diet. Therefore, animals lacking Lys in the diet will work to receive complete diet, but replacement of Lys by drinking, chronic IP infusion, or directly into the lateral hypothalamic area inhibits bar pressing behavior.

Cervical/vaginal dysplasias of transgenic mice harbouring human papillomavirus type 16 E6-E7 genes

Half of the female transgenic mice harbouring human papillomavirus type 16 (HPV-16) E6-E7 genes under control of the mouse mammary tumour virus promoter, developed malignant tumours, including salivary gland carcinomas, lymphomas and skin histiocytomas. Although the E6-E7 genes are aetiological factors for human anogenital carcinoma, the transgenic mice produced no tumours in the anogenital tract. We investigated cytological and histological changes in the anogenital tract of the same transgenic mice. Seventeen (77%) of 22 transgenic mice developed dysplastic and/or hyperplastic changes in the cervix and vagina. HPV-16 E6-E7 mRNA signals were observed in the genital lesions, while they were not detected in the normal cervices and vaginas of transgenic mice and control mice by RNA in situ hybridization analysis. RNA/PCR analysis using poly(A)+ RNA showed that only a full-length E6-E7 RNA was expressed in three scraped cell samples from dysplasia, whereas full-length and spliced E6-E7 transcripts were in three cell samples from dysplasia/hyperplasia. These results suggest that expression of both E6 and E7 genes of HPV-16 is important for inducing dysplastic and hyperplastic changes in the genital epithelium.