Properties of Ca(2+)-mediated inactivation of L-type Ca channel in smooth muscle cells of the guinea-pig urinary bladder

The properties of Ca(2+)-mediated inactivation as revealed by a conventional double-pulse protocol were examined by using the whole-cell patch clamp technique. A U-shaped relationship between the conditioning potential and the Ca2+ current (ICa) inactivation was observed, with a maximum inactivation of 52 +/- 4% (n = 5) at 10 mV with 0.5 mM EGTA in the patch pipettes. The maximum inactivation was reduced significantly, to 31 +/- 5.7% (n = 12) and 32 +/- 7.0% (n = 5), when a high concentration of EGTA (20 mM) or a more efficient Ca2+ chelator, BAPTA, was included in the patch pipettes, respectively. The same double-pulse protocol was applied under conditions where the stored Ca2+ was depleted by using caffeine or the stored Ca2+ release function was blocked by using ryanodine or procaine and heparin. No significant difference in the maximum ICa inactivation before (45%) and after (50%) application of 10 mM caffeine was observed. The maximum ICa inactivations of 48 +/- 3.2% (n = 4) and 52 +/- 8.4% (n = 6) were still observed after treatment of the cell with ryanodine (20 microM) or loading 10 mM procaine and 1 mg/mL heparin in the patch pipettes, respectively. These results suggest that Ca2+ mobilization from an internal Ca2+ store is not essential for the Ca(2+)-mediated inactivation observed in the double-pulse experiment, rather influx of Ca2+ through a voltage-dependent Ca channel seems to be important for ICa inactivation.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of galactosamine-induced hepatitis on the aerobic and anaerobic metabolism of the rat exposed to high-altitude hypoxia

Galactosamine-induced hepatitis caused a marked increase in plasma lactate and pyruvate, but completely abolished the increase in ketone bodies in the rat exposed to an 8000 m simulated altitude. Plasma free fatty acid as the precursor of ketone bodies was higher in the galactosamine-treated rats during and after an exposure to 8000 m altitude. Treatment of the rat with galactosamine markedly reduced activities of citrate synthase, fumarase, glutamate dehydrogenase and fructose 1,6-bisphosphatase, but increased hexokinase and glucose 6-phosphate dehydrogenase in the liver. The effect of galactosamine-induced hepatitis on the energy metabolism can be explained by a reduction of mitochondrial oxidative enzymes and gluconeogenesis, and involves a shift of the aerobic metabolism to anaerobic glycolysis at high altitude.

Hotspots of homologous recombination in mouse meiosis

The molecular mapping of recombinational breakpoints in the proximal region of the mouse MHC has revealed four hotspots at which breakpoints are clustered. A direct comparison of the nucleotide sequences of two independent hotspots revealed common molecular elements: a consensus sequence of the middle-repetitive MT-family, a repeat of tetramer sequences and a sequence homologous to a solitary LTR of mouse retroviruses. Extremely high frequency of recombination is observed at these hotspots when particular MHC haplotypes are used in genetic crosses. Wild mouse-derived wm7 haplotype instigates recombination at the hotspot located at the 3'-end of the Lmp-2 gene only during female meiosis. Fine genetic analysis demonstrated that the wm7 haplotype carries a genetic factor to instigate recombination and another factor to suppress recombination specifically during male meiosis. In addition, there is no dose effect of the hotspot on frequency of recombination. Finally, we described an attempt to establish an efficient in vitro assay system for monitoring recombination using plasmid DNAs that contain the Lmp-2 hotspot and nuclear extracts prepared from mouse testis.

Molecular characterization of galactosemia (type 1) mutations in Japanese

We characterized two novel mutations of the galactose-1-phosphate uridyltransferase (GALT) gene in two Japanese patients with GALT deficiency and identified N314D and R333W mutations, previously found in Caucasians. One novel missense mutation was an G-to-A transition in exon 8, resulting in the substitution of arginine by histidine at the codon 231 (R231H). GALT activity of the R231H mutant construct was reduced to 15% of normal controls in a COS cell expression system. The other was a splicing mutation, an A-to-G transition at the 38th nucleotide in exon 3 (318A-->G), resulting in a 38-bp deletion in the GALT cDNA by activating a cryptic splice acceptor site. In seven Japanese families (14 alleles for classic form and one allele for Duarte variant) with GALT deficiency, the R231H and 318A-->G mutations were found only on both alleles of the proband. The N314D and R333W mutations were found on one allele each. The Q188R was prevalent in the United States but not in Japanese patients. The N314D mutation was associated with the Duarte variant in Japanese persons, as well as in the United States. We speculate that classic galactosemia mutations appear to differ between Japanese and Caucasian patients. Our limited data set on galactosemia mutations in Japanese suggests that the N314D GALT mutation encoding the Duarte variant arose before Asian and Caucasian people diverged and that classic galactosemia mutations arose and/or accumulated after the divergence of Asian and Caucasian populations.

A phase II study of cisplatin in patients with biliary tract carcinoma

A phase II study of cisplatin was performed in 13 previously untreated patients with unresectable biliary tract carcinoma. The drug was given intravenously at a dose of 80 mg/m2/day once every 4 weeks. Of 13 patients evaluated, 1 showed partial response lasting 3 months, while no patients showed complete response. Of 9 patients, whose serum level of carcinoembryonic antigen (CEA) was high (> or = 10 ng/ml) before treatment, 4 showed > or = 50% reduction in serum CEA level after treatment. The current study indicates that cisplatin does not have significant antitumor activity against biliary tract carcinoma.

Recombination in the class III region of the mouse major histocompatibility complex

The sites of meiotic recombination in the class II region of the mouse major histocompatibility complex (MHC) are clustered at hotspots. To search for hotspots in the class III region, we mapped recombinational breakpoints of 79 Ab:H2-D recombinants with 11 DNA markers; these included Tnx, the gene for an extracellular matrix protein, tenascin X, the Notch-related Int3 gene, and a microsatellite marker, D17Mit13, none of which had previously been mapped precisely. The results gave the gene order of Eb-61.1-Int3-Tnx-Cyp21/C4-Bf-Hsp68c-D17Mit13+ ++-Tnfa/Tnfb-D. The crossover sites in 40 of the 79 recombinants were confined within the Eb/Int3:Tnx/Cyp21 interval. The result demonstrated that an unequal distribution of recombination is a general feature of the mouse MHC, suggesting the presence of a recombinational hotspot within the Int3:Tnx interval.

Clinical significance of diffuse delta EEG activity in chronic schizophrenia

1) Forty-three chronic schizophrenics with diffuse delta activity (DDA) in their rest-awake EEGs were compared with 23 chronic schizophrenics with normal EEGs. 2) The DDA group was divided into three sub-groups according to the temporal persistence of DDA: brief, intermittent, and prolonged. The intermittent DDA is analogous to intermittent rhythmic delta activity (IRDA). 3) The disorganized type of schizophrenia was frequent in the DDA group and the residual type was frequent in the normal EEG group. 4) The doses of neuroleptics, as well as those of phenothiazines and butyrophenones, were higher in the DDA than in the normal group. 5) The frequency of co-administration of carbamazepine was higher in the DDA than in the normal group, and the rate increased with the degree of abnormality. 6) In a 1 year follow-up of the DDA group, reducing doses of neuroleptics resulted in a tendency for DDA to disappear, and reducing the doses of adjunctive carbamazepine caused DDA to disappear. 7) There was no correlation between DDA and the psychiatric symptoms, intelligence level, or CT findings.

Dropout of young non-insulin-dependent diabetics from diabetic care

We investigated the follow-up status and prognosis of 109 patients with non-insulin-dependent diabetes mellitus aged from 10 to 19 years old (66 males and 43 females). Patients who had not attended hospital for at least 20 months up to the end of September 1990 were regarded as defaulters, and were surveyed by questionnaire. There were 62 defaulters (56.9%) among the 109 patients originally enrolled in diabetes care. The defaulters had a significantly higher body mass index (both males and females), mean arterial blood pressure, and fasting blood glucose level than the patients still attending the diabetes clinic, as well as a significantly worse lipid profile. The main reason given for non-attendance was a busy schedule. Compared with patients attending the diabetes clinic, a lower percentage of the defaulters remained on a diet or took regular exercise. Rapid eating was more common among the defaulters than the attendees (92.9% vs. 60%, P = n.s.). Thus, the lifestyle of the defaulters seemed to be undesirable for young diabetic patients. These findings emphasize the importance of effective education and follow-up for young obese patients with non-insulin-dependent diabetes mellitus.

[Late phase II study of irinotecan hydrochloride (CPT-11) in advanced gastric cancer. CPT-11 Gastrointestinal Cancer Study Group]

A multi-institutional collaborative late phase II study of irinotecan hydrochloride (CPT-11) was performed on patients with advanced gastric cancer. CPT-11 was administered as a 100 mg/m2 weekly intravenous infusion or as 150 mg/m2 fortnightly. Of 81 registered patients, 77 cases were eligible and 60 cases were evaluable for response. The overall response rate for evaluable cases was 23.3% (14/60), and the response rate was 16.1% (9/45) for the patients who had received prior chemotherapy. The primary tumor showed a 4.5% response, while metastatic lesions in the lymph-nodes, lungs, and liver showed response rates of 36.4%, 33.3%, and 17.4%, respectively. The major toxicities (> or = Grade 3) were leukopenia (41.2%), anemia (28.9%), diarrhea (22.4%) and anorexia (19.7%). These toxicities were generally reversible. CPT-11 showed activity against advanced gastric cancer, suggesting that further clinical studies of CPT-11 combined with other active chemotherapy agents are warranted.

[A late phase II study of CPT-11, irinotecan hydrochloride, in patients with advanced pancreatic cancer. CPT-11 Study Group on Gastrointestinal Cancer]

A late phase II study of CPT-11 was conducted to evaluate the antitumor effect and toxicity of CPT-11 in patients with advanced pancreatic cancer as a cooperative study of 19 institutions. From February 1990 to June 1992, 61 patients with advanced pancreatic cancer were enrolled in this study. Fifty-seven patients were evaluable for toxicity and 35 for response. CPT-11 was administered as a 100 mg/m2 weekly intravenous infusion (regimen A) or as a 150 mg/m2 every two weeks (regimen B). The response rate was 11.4% (4/35). The primary tumor showed a 10.3% (3/29) response and the liver metastases showed a 10.5% (2/19) response. The major toxicities were myelosuppression and gastrointestinal symptoms. The incidences (> or = Grade 2) of leukopenia, anemia, anorexia, nausea/vomiting, alopecia and diarrhea were 61.4% (35/57), 56.1% (32/57), 70.2% (40/57), 56.1% (32/57), 40.4% (23/57) and 36.8% (21/57), respectively. The incidence of diarrhea was higher with regimen A than with regimen B, but the antitumor activity was no different between the two regimens. These results suggested that CPT-11 has some antitumor activity against advanced pancreatic cancer.

Benign neurogenic amyotrophy in Klinefelter's syndrome

Two cases of benign neurogenic amyotrophy associated with Klinefelter's syndrome are reported. Both presented with slowly progressive, diffuse neurogenic muscle atrophy of juvenile onset. Both had a karyotype of XXY. Amplification, by the polymerase chain reaction, of a fragment of androgen receptor that was related to bulbospinal muscular atrophy, showed no abnormality. Treatment with androgen in one case provided no benefit. Benign neurogenic amyotrophy in the Klinefelter's syndrome is likely to be an independent type of motor neuron disease and suggests that the X chromosome plays an important part in the biology of motor neurons.

Sex determination from the tibia: standards for contemporary Japan

It is vital that skeletal biologists and forensic anthropologists observe populations over time so that changes can be detected and monitored. The purpose of this study is to determine if temporal changes are manifest in the skeleton and, if so, develop appropriate standards to determine sex from the tibia in the contemporary inhabitants of Japan. Osteometric data were obtained from 84 recent Japanese skeletons located at Jikei Medical University, Tokyo. The collection was assembled from the anatomy dissecting room between 1960-1970. With a mean age of about 56 years for males and 51 for females, this sample represents individuals who lived through WWII. Seven tibial measurements were taken and subjected to SPSS-X discriminant function analysis. Results indicated that proximal and distal breadth measurements were selected by the stepwise procedure as the most discriminating. In addition, a number of combinations of measurements were used to develop formulae that would be suitable for fragmentary bones. Average prediction accuracy ranged from 80% from minimum shaft circumference to 89% with proximal epiphyseal breadth. Classification accuracy was higher in males (96%) than in females (79%). Compared with earlier studies of the Japanese, Jikei tibiae are longer, especially in females and thus exhibit less sexual dimorphism. The present research provides new standards that better reflect the Japanese people of today. Furthermore, unlike earlier length based formulae, these results allow sexing from fragmentary bones.

No dosage effect of recombinational hotspots in the mouse major histocompatibility complex

The sites of meiotic recombination in the proximal region of the mouse major histocompatibility complex (MHC) are clustered at hotspots. Some MHC haplotypes derived from Asian wild mice increase the frequency of recombination at such hotspots when heterozygous with standard laboratory haplotypes. The wm7 and cas3 haplotypes have a hotspot close to the Lmp-2 gene (Lmp-2 hotspot), and the cas4 haplotype has a hotspot about 100 kilobase (kb) proximal, close to the Pb gene (Pb hotspot). To examine the effect of a double dose of hotspots, we estimated the rate of recombination and determined the location of the breakpoints in crosses of wm7/cas3 and wm7/cas4. In 3570 backcross progeny we identified 29 new recombinants in the H-2K to Ab interval, at a frequency of 0.81%. This frequency is 40-fold higher than in crosses between laboratory haplotypes and very similar to those previously obtained in crosses between these wild and standard laboratory haplotypes. Thus, a double dose of hotspots has no additive effect on the frequency of meiotic recombination. The site-specificity of recombination was also conserved. Twenty-three breakpoints were confined within 5.4 kb in the Lmp-2 hotspot, and six breakpoints from the cas4 cross were located in the Pb hotspot, which we have now confined to a 15 kb segment.

Histological estimation of age at death using microradiographs of humeral compact bone

The purpose of this study is to develop an age estimating method for skeletal remains using microradiographs of compact bone. Compact bones of the humerus were collected from 40 Japanese males ranging from 23 to 80 years of age. Microradiographs taken from cross-sections were histomorphometrically examined by using an image analyzer. Histological parameters used in this study included 10 items, that is, osteon number, double-zoned osteon number, type II osteon number, low-density osteon number, osteon fragment number, resorption space number, total and average osteon area, and total and average Haversian canal area. The osteon fragment number showed the highest correlation coefficient with advancing age (r = 0.786). The measurement data obtained from 10 histological parameters were subjected to multiple regression analysis for producing multiple regression equations for age estimation. In practice, 8 histological parameters were selected for the equation and its multiple correlation coefficient and standard error of estimate were 0.903 and 6.1, respectively.

Role of glutamate dehydrogenase reaction in the control of citrate pool in yeast

1. Role of NADP-glutamate dehydrogenase in the depletion of citrate was analyzed using permeabilized yeast cells. 2. Citrate was converted to 2-oxoglutarate, which was then metabolized to glutamate by NADP-glutamate dehydrogenase in the presence of ammonium ion. 3. Formation of 2-oxoglutarate plus glutamate was in good agreement with the concentration of citrate decreased. Glutamate formation can be a good indicator of the depletion of citrate, because 70% of the citrate decreased was converted to glutamate. 4. Glycolytic activity was closely correlated with the decrease in citrate under the in situ conditions. 5. NADP-glutamate dehydrogenase increased in anaerobically grown yeast cells. 6. An effective depletion of citrate by increased synthesis of NADP-glutamate dehydrogenase can explain the lowered mechanism of citrate causing glycolytic stimulation under the anaerobic growth conditions of yeast.

Phase II study of CPT-11, a new camptothecin derivative, in metastatic colorectal cancer. CPT-11 Gastrointestinal Cancer Study Group

PURPOSE

A phase II study was conducted to evaluate the antitumor effect and toxicity of CPT-11 in patients with metastatic colorectal cancer.

PATIENTS AND METHODS

From December 1989 to March 1991, 67 patients with metastatic colorectal cancer were enrolled in this study. Sixty-three patients were assessable for toxicity and response. Their median age was 57 years (range, 24 to 72). Forty-six patients (73%) had a good performance status of 0 or 1. Fifty-one patients (81%) had received prior chemotherapy. The major sites of metastasis were liver (63%) and lung (44%). CPT-11 was administered as a 100 mg/m2 weekly intravenous infusion, or as 150 mg/m2 every 2 weeks. The dose was reduced based on the grade of leukopenia and diarrhea, if necessary.

RESULTS

A partial response was obtained in 17 of 63 assessable patients (27%; 95% confidence interval, 16% to 38%). The response rate in patients with prior radiotherapy or chemotherapy was 25% (13 of 52). Liver metastases showed a 15% (six of 40) response and lung metastases showed a 39% (11 of 28) response. The median duration of partial response was 127 days (range, 49 to 353) and the median overall duration of response was 208 days (range, 99 to 381). The major toxicities (> or = grade 3) were leukopenia (16%), diarrhea (13%), nausea and vomiting (13%), and alopecia (11%). Adverse effects were generally well tolerated and reversible. Treatment could be continued on an outpatient basis for patients without severe toxicity. Hemorrhagic cystitis was not encountered in this study.

CONCLUSION

CPT-11 showed promising antitumor activity against metastatic colorectal cancer that was resistant to prior therapy. Further clinical trials of combination chemotherapy using CPT-11 are justified.

Human seminal phosphatase. Properties and comparison with plant phosphatases

1. Phosphatase activities were determined in various seminal fluid and plant tissues. 2. Human semen showed a markedly higher phosphatase activity, and some plants and mushrooms exhibited a considerably higher phosphatase activity. 3. Phosphatase purified from human seminal fluid showed a pH optimum of 5-6 and was potently inhibited by L-(+)-tartrate. 4. Tartrate could not inhibit most plant phosphatases, but inhibited the mushroom phosphatase with a one-order lower affinity than that of the seminal enzyme.

De-acclimatization process of rats acclimatized to high altitude hypoxia

The de-acclimatization process in rats acclimatized to high altitude hypoxia was analyzed according to the changes in the activities of hepatic enzymes. The activities of tryptophan 2,3-dioxygenase and tyrosine aminotransferase in the liver of non-acclimatized rats were increased, whereas those of acclimatized rats were decreased after exposure to a simulated altitude of 8,000 m. When the acclimatized rats were kept under normoxic conditions for 8 days and over, the suppression of enzyme induction was nullified, and both enzymes were induced by exposure to the simulated 8,000 m altitude. De-acclimatization of rats acclimatized to hypoxia can be completed in 8-11 days.

Carbonic anhydrase II deficiency in three unrelated Japanese patients

Three Japanese patients with carbonic anhydrase II (CAII) deficiency from three families were described. The parents of one patient were unrelated, the parents of each of the other two patients were first cousins. All the patients had renal tubular acidosis, osteopetrosis, symmetrical cerebral calcification and mental retardation. They exhibited poor activity and poor appetite in the neonatal period, and then developed psychomotor retardation. Two of them were diagnosed as having osteopetrosis at 10 months and 36 years of age, respectively, and the other as having osteomalacia at 28 years of age. All patients had recurrent episodes of muscle weakness. The CAII enzyme activity and protein levels in red blood cells in each of the three patients were deficient. Their parents exhibited approximately 50% normal levels of CAII activity and protein. This is the first report of patients with CAII deficiency in the Japanese population.

Inhibition by aluminum ion of NAD- and NADP-dependent isocitrate dehydrogenases from yeast

1. NADP-dependent isocitrate dehydrogenase from yeast was potently inhibited by aluminum ion competitively with respect to the substrate isocitrate, and noncompetitively with the other substrate NADP. Ki value was determined to be 0.43 microM. 2. Aluminum ion acted as only a weak allosteric inhibitor of yeast NAD-dependent isocitrate dehydrogenase toward isocitrate, and as a noncompetitive inhibitor toward NAD. 3. Inhibition by aluminum ion of NADP- and NAD-isocitrate dehydrogenases can reduce the aerobic energy production in yeast, and may contribute to the biological toxicity of aluminum in ecosystems and human life.

The amplified long genomic sequence (ALGS) located in the centromeric regions of mouse chromosomes

We reported previously that the haploid genome of standard strains of laboratory mice contains approximately 70 copies of an amplified long genomic sequence, designated ALGS, that includes a retroposon of the gene for elongation factor 2 (MER). The length of each repeating unit is more than 60 kb, and the sequence of the unit is highly conserved among the repeats. In the present study, Southern blot analysis of the genomes of wild rodents demonstrated that the ALGS is present in all subspecies of Mus musculus and is abundant in M. spicilegus, whereas it is absent in M. spretus as well as in Rattus and other closely related genera. This result indicates that the amplification occurred after the species differentiation with the genus Mus and at least prior to the differentiation of subspecies of M. musculus. To locate chromosomal positions of the ALGS, in situ hybridization was carried out with laboratory strains and wild mice. It appears that the ALGS is located in the centromeric regions of most chromosomes in laboratory mice, M. musculus and M. spicilegus, whereas no positive signals were observed with M. spretus, in accordance with the results from the Southern blotting analysis.

Changes in ventricular 1,2-diacylglycerol content in rats following monocrotaline treatment

OBJECTIVE

1,2-Diacylglycerol may initiate cardiac hypertrophy, probably by activating protein kinase C. To test this hypothesis we determined the 1,2-diacylglycerol content of hypertrophied tissue.

METHODS

Rats were treated with monocrotaline and developed severe right ventricular hypertrophy followed by congestive heart failure. 1,2-Diacylglycerol content and fatty acid composition, DNA concentrations, and RNA concentrations in the right ventricle from monocrotaline treated rats were compared with values obtained from the left side or from control rats.

RESULTS

During the first week, the right ventricle showed no significant change in 1,2-diacylglycerol content and a small increase in RNA concentration. However, the 1,2-diacylglycerol content was significantly increased by 55% at two weeks after monocrotaline injection, when DNA and RNA synthesis was also enhanced to its highest level when compared with control rats (37% and 18%, respectively). At four weeks after monocrotaline injection, conversely, the 1,2-diacylglycerol content was decreased by 25% in the right ventricle from monocrotaline treated rats, most of which had pleural and peritoneal effusions indicating congestive heart failure, although RNA synthesis was sustained at a high level. The fatty acid composition of 1,2-diacylglycerol did not differ significantly between the right and left ventricles or control rat ventricles.

CONCLUSIONS

These results suggest that 1,2-diacylglycerol accumulation is associated with development of hypertrophy in monocrotaline treated rats. In contrast, at a stage of congestive heart failure 1,2-diacylglycerol production decreased, suggesting that intracellular transduction mechanisms may be attenuated.