Resonant photorefractive effect in InGaAs/GaAs multiple quantum wells

Semi-insulating InGaAs/GaAs multiple quantum wells are fabricated by metal-organic vapor-phase epitaxy and proton implantation. Two-wave mixing gain and four-wave mixing diffraction efficiency are measured at wavelengths of 0.91-0.94microm in the Franz-Keldysh geometry. We observe a large photorefractive effect caused by the excitonic electro-optic effect. The maximum diffraction efficiency reaches ~1.5x10(-4) .

Development and clinical application of high performance liquid chromatography for the simultaneous determination of plasma levels of theophylline and its metabolites without interference from caffeine

A high performance liquid chromatography (HPLC) method has been developed for the simultaneous determination of plasma levels of theophylline and its metabolites without interference from caffeine or caffeine metabolites. The method is simple and of practical use because it is applicable even to plasma samples from patients who take caffeine-containing beverages. The method was also reproducible with a coefficient of variation of less than 5% for each analyte. The levels of theophylline, determined by HPLC, were validated by their high correlation to the levels obtained by fluorescence polarization immunoassay. HPLC was used to determine theophylline levels in patients with bronchial asthma. The data revealed that the ratio of 1,3-dimethyluric acid, the major metabolite of theophylline, to theophylline concentration in the plasma was within a narrow range in most patients (0.055 +/- 0.01, n = 66), regardless of the method of theophylline administration or the time of blood sampling. Conversely, this ratio was as low as 0.027 +/- 0.005 in the patient with a long plasma half-life of theophylline. These results suggest that it may be possible to predict the plasma half-life of theophylline for each patient from a single blood sample. This may be useful when planning theophylline administration, especially in patients with abnormal theophylline metabolism.

Host genes affecting survival period of chemically induced bladder cancer in mice

Treatment of C57BL/6 J (B6) and NON male mice with N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) resulted in a high incidence of bladder cancer. The mean survival period, however, differed significantly by strain: 481+/-219 days in B6 (n = 31) and 203+/-119 days in NON (n = 30) (P < 0.0001). Major causes of death were renal failure due to obstruction of the urinary tract, or local invasion of tumors. The fact that the BBN-treated NON x B6 reciprocal F1 mice had survival periods as short as those of the parental NON mice suggests a genetically dominant susceptibility in NON or recessive resistance in B6. A linkage analysis of 248 back-cross mice to B6 suggested at least two quantitative trait loci determining the length of the survival period: one was mapped close to D2Mit260 (logarithm of odds, LOD, score 2.21), a microsatellite marker locus 83 cM from the centromere on chromosome 2, and another was close to D6Mit159, 7 cM from the centromere on chromosome 6 (LOD score 2.51).

Gastric epithelial cells stimulate Helicobacter pylori growth

Helicobacter pylori infects only human gastric epithelium, causes gastritis, and is strongly associated with gastroduodenal ulceration and gastric cancer. Colonization of the stomach with H. pylori is accompanied in the acute stage by an increased number of neutrophils in the lamina propria, indicative of gastric inflammation. It is interesting that H. pylori colonizes specifically human gastric-type epithelial cells. We studied whether the presence of gastric epithelial cells influenced H. pylori growth. H. pylori (NCTC 11637) was cultured on Skirrow agar with 7% horse blood. Kato-III cells, a human gastric cancer cell line, were cultured with RPMI 1640 plus 10% fetal bovine serum (FBS). Kato-III cells (10(5)/ml) were cultured with/ without H. pylori (10(8) cfu/ml) with RPMI 1640 + 1% FBS for 3 days. The number of Kato-III cells was counted with a hemacytometer. H. pylori with/without Kato-III cells was cultured with RPMI 1640 + 10% FBS for 2 hours, and plated on Skirrow agar. After 3 days we counted the number of H. pylori colonies. To detect the H. pylori colonies, we used a colony hybridization method. DNA of colonies was transferred to positively charged nylon membrane and hybridized by PCR with Hpl (5'-CTG-GAG-AGA-CTA-AGC-CCT-CC-3') and Hp2 (5'-ATT-ACT-GAC-GCT-GAT-TGT-GC-3')-amplified primers. We previously reported that the number of Kato-III cells was significantly decreased by co-incubation with H. pylori. The number of H. pylori colonies was significantly increased by coincubation with Kato-III cells. We conclude that the presence of human gastric epithelial cells is important for the growth of H. pylori.

Rathke cleft cyst: MR and biomedical analysis of cyst content

PURPOSE

At least one type of Rathke cleft cyst has unique MR findings, specifically, high intensity on T1-weighted images and iso- to low intensity on T2-weighted images relative to white matter. To clarify the influence of cyst content on MR images, we analyzed the cyst content by biomedical methods after surgical removal.

METHOD

We studied five patients diagnosed with Rathke cleft cyst, whose MR images showed high intensity on T1-weighted images and iso- to low intensity on T2-weighted images. After surgery, total protein and cholesterol levels were quantified, and correlations of protein and cholesterol content with T1 and T2 signal intensities were performed in vitro.

RESULTS

All five cysts had very high concentrations of protein (11,700-26,600 mg/dl, mean 17,940 mg/dl) with nearly no cholesterol (at most 2.0 mg/dl). Along with increases in protein concentration in vitro, the signal intensity of T1-weighted images increased, while that of T2-weighted images decreased. In contrast, the cholesterol concentration sequence influenced the signal intensity of neither T1- nor T2-weighted images.

CONCLUSION

The unique MR finding of Rathke cleft cysts--high signal intensity on T1-weighted images and low signal intensity on T2-weighted images--might depend mainly on protein concentration, not on cholesterol.

Protective role of melatonin and the pineal gland in modulating water immersion restraint stress ulcer in rats

We investigated the protective effect of melatonin on stress-induced gastric lesions in rats. Fasted rats were subjected to water immersion restraint stress for 4 h and the percentage of corpus mucosa containing hemorrhagic lesions was determined. Thirty minutes before restraint stress, melatonin or vehicle was administered i.p. In another experiment, pinealectomy was performed 1 week before water immersion restraint stress. Administration of melatonin at 1 and 5 mg/kg significantly decreased gastric lesions by 46 and 74%, respectively. In contrast, pinealectomy significantly enlarged the lesion area, although this effect was counteracted by melatonin at a dose of 1 mg/kg i.p. However, this protective effect of melatonin was abolished by i.p. pretreatment with indomethacin at 5 mg/kg. These results suggest that melatonin has gastroprotective properties against stress-induced gastric injury in rats and that the pineal gland contributes to gastric protection via prostaglandin-dependent mechanisms.

Central nervous system action of melatonin on gastric acid and pepsin secretion in pylorus-ligated rats

We recently demonstrated that centrally administered melatonin at low doses inhibits the induction of gastric lesions by water-immersion restraint stress. To investigate the mechanism of the potent anti-ulcer action of melatonin, the central nervous system (CNS) effects of melatonin on gastric acid and pepsin secretion were studied in conscious pylorus-ligated rats. Intracisternal (i.c.) melatonin (1-100 ng) dose-dependently decreased acid and pepsin output, while a higher i.p. dose (1 microg) had no inhibitory effect. The i.c. melatonin did not change serum gastrin concentrations. Serum melatonin concentrations at 1 and 4 h after i.c. administration of 10-100 ng melatonin did not differ from those in rats receiving i.c. vehicle. The present results suggest that melatonin administered centrally modulates the secretion of gastric acid and pepsin which may explain, at least in part, the protective, anti-stress role of melatonin in the gastric mucosa observed in our previous study.

Percutaneous Transluminal Angioplasty (PTA) with Wallstent for Internal Carotid Artery Stenosis. A Case Report

SUMMARY

A 67 year-old male who had suffered from myocardial infarction, was admitted to our clinic to examine his internal carotid artery stenosis revealed by preoperative study for heart surgery. Although he had no neurological symptoms, the angiograms showed severe stenosis of his right internal carotid artery. To improve stenotic internal carotid artery, PTA was performed employing a selfexpanding stent. The stenotic right internal carotid artery was improved from 75% to 11% immediately after the stenting though restenosis mildly occurred up to 16% three months later. No complication occurred during this stenting procedure. Afterwards the patient uneventfully received coronary artery bypass grafting (CABG) surgery.

Hepatocellular carcinomas infected with the novel TT DNA virus lack viral integration

A novel DNA virus designated TT virus (TTV) was cloned from a patient with posttransfusion hepatitis and is thought to be a new hepatitis virus. At present, hepatitis B virus (HBV) and hepatitis C virus (HCV) are known to induce hepatocellular carcinoma (HCC). But, actually, in Japan approximately 5 to 10% of HCCs are in HBV-negative and HCV-negative (NBNC) patients. In order to study the possible role of TTV in hepatocarcinogenesis, we investigated the frequency of the TTV genome in liver tissue of 20 HCC patients. As a result, 3 of 8 NBNC HCC patients and 5 of 12 HBV- or HCV-associated HCC patients were TTV positive, and TTV was shown not to be specific for NBNC HCC. For all TTV-positive patients, we also confirmed that the TTV genome was not integrated into host hepatocyte DNA.

Conserved structural regions involved in the catalytic mechanism of Escherichia coli K-12 WaaO (RfaI)

Escherichia coli K-12 WaaO (formerly known as RfaI) is a nonprocessive alpha-1,3 glucosyltransferase, involved in the synthesis of the R core of lipopolysaccharide. By comparing the amino acid sequence of WaaO with those of 11 homologous alpha-glycosyltransferases, four strictly conserved regions, I, II, III, and IV, were identified. Since functionally related transferases are predicted to have a similar architecture in the catalytic sites, it is assumed that these four regions are directly involved in the formation of alpha-glycosidic linkage from alpha-linked nucleotide diphospho-sugar donor. Hydrophobic cluster analysis revealed a conserved domain at the N termini of these alpha-glycosyltransferases. This domain was similar to that previously reported for beta-glycosyltransferases. Thus, this domain is likely to be involved in the formation of beta-glycosidic linkage between the donor sugar and the enzyme at the first step of the reaction. Site-directed mutagenesis analysis of E. coli K-12 WaaO revealed four critical amino acid residues.

Central nervous system action of melatonin on gastric acid and pepsin secretion in pylorus-ligated rats

We recently demonstrated that centrally administered melatonin at low doses inhibits the induction of gastric lesions by water-immersion restraint stress. To investigate the mechanism of the potent anti-ulcer action of melatonin, the central nervous system (CNS) effects of melatonin on gastric acid and pepsin secretion were studied in conscious pylorus-ligated rats. Intracisternal (i.c.) melatonin (1-100 ng) dose-dependently decreased acid and pepsin output, while a higher i.p. dose (1 microg) had no inhibitory effect. The i.c. melatonin did not change serum gastrin concentrations. Serum melatonin concentrations at 1 and 4 h after i.c. administration of 10-100 ng melatonin did not differ from those in rats receiving i.c. vehicle. The present results suggest that melatonin administered centrally modulates the secretion of gastric acid and pepsin which may explain, at least in part, the protective, anti-stress role of melatonin in the gastric mucosa observed in our previous study.

Induction of protection against oral infection with cytotoxin-producing Escherichia coli O157:H7 in mice by shiga-like toxin-liposome conjugate

We have previously reported that purified Shiga-like toxins (SLT), SLT-I and SLT-II coupled with liposomes induced a substantial amount of anti-SLT-I and anti-SLT-II IgG antibody production, respectively, in mice. The levels of anti-SLT antibody in the sera of SLT-liposome-immune mice correlated well with the protection against subsequent challenge with SLT. In this study, mice were immunized intraperitoneally with the mixture of SLT-I-liposome and SLT-II-liposome and protection against oral infection with cytotoxin-producing Escherichia coli O157:H7 was evaluated. All of the mice that received immunization with the mixture of SLT-I-liposome and SLT-II-liposome were protected against subsequent intravenous challenge with 10 LD50 of either SLT-I or SLT-II. Eight weeks after primary immunization, mice were inoculated intragastrically with 10(9) CFU of E. coli O157:H7 strain 96-60. All SLT-liposome-immune mice tested survived without any apparent symptom while control mice died within 5 days. In addition, as shown by other antigen-liposome conjugates, SLT-liposome induced undetectable anti-SLT IgE antibody production while they induced substantial amounts of anti-SLT IgG antibodies. These results suggest that SLT-liposome conjugate may serve as a candidate vaccine that induces protection against cytotoxin-producing E. coli infection.

Detection of Coxiella burnetii specific DNA in blood samples from Japanese patients with chronic nonspecific symptoms by nested polymerase chain reaction

The nested polymerase chain reaction (PCR) was used for direct species-specific detection of Coxiella burnetii in blood samples from 52 patients with chronic nonspecific symptoms, but no diagnostic or treatment history of Q fever. All patients had been in ill-health with general fatigue, muscle and joint pain, headache, etc., for one to more than 10 years. Seventeen (33%) showed evidence of C. burnetii infection, based on amplification of 438-bp fragments specific to C. burnetii by nested PCR, and 94% of positive patients reported close contact with animals. In contrast, five (9.6%) of 52 samples from healthy adult controls and two (2.8%) of 70 cord blood samples were positive by nested PCR. These data suggest a high prevalence of infection among adult patients with long term, nonspecific complaints who live in close contact with animals and the possible existence of a chronic post-acute Q fever syndrome in Japan.

[Hepatic osteodystrophy]

Bone thinning causing both fractures and severe pain not associated with fractures has been recognized in patients with chronic liver diseases. The patients most commonly affected are those with primary or secondary biliary cirrhosis, but those with alcoholic liver disease and cirrhosis after active chronic hepatitis may also be involved. Chronic liver disease has also been recognized as an important cause of osteoporosis in both sexes, with the mechanism thought to be a combination of calcium and/or vitamin D. The 9.1% patients with chronic active hepatitis accompanied with osteodystrophy. But 50% cirrhotic patients accompanied with osteodystrophy. Bone densitometry was determined by Digital Image Processing Method (Osteodystrophy < mean-2SD: age- and sex-matched normal value). Serum levels of osteocalcin (BGP) and parathyroid hormone (PTH) in patients of hepatic cirrhosis without osteodystrophy were lower than those with osteodystrophy. These results were suggested that hepatic osteodystrophy was rapidly turnover osteodystrophy. To function physiologically, vitamin D must be hydroxylation in liver to 25-(OH)-D and subsequently by the kidney to 1 alfa, 25-(OH)2-D. Osteodystrophy associated with hepatic cirrhosis is due to a defect in the 1 alfa-hydroxylation by the kidney rather than a hepatic hydroxylation defect. 1 alfa OH-D3 is very useful for treatment for hepatic osteodystrophy.

Lansoprazole elevates the ratio of serum pepsinogen I v.s. pepsinogen II

In order to investigate the mechanism by which proton pump inhibitor increases serum pepsinogen levels, we evaluated the effects of ulcer location and IgG antibody against Helicobacter pylori on lansoprazole-induced elevations. Patients with endoscopically proven peptic ulcer received lansoprazole 30 mg/day for 6 or 8 weeks; pepsinogen I and II levels, along with antibody to H. pylori, were measured in fasting blood samples. We found that whether or not antibody to H. pylori was present, pepsinogen I and II levels and the I/II ratio rose significantly in lansoprazole-treated patients. Patients with stomach-body ulcers showed smaller increases in both pepsinogens than did those with ulcers in the gastric angle/antrum or in the duodenum. In conclusion, lansoprazole increases serum levels of both pepsinogens I and II, although a larger increase in pepsinogen I elevates the pepsinogen I/II ratio. The relatively small increases seen in patients with stomach-body ulcers suggest atrophic changes in the gastric mucosa in patients with stomach-body ulcer.

Effect of barbiturate on central pain: difference between intravenous administration and oral administration

OBJECTIVE

To examine whether the oral administration of barbiturates is of clinical use in a patient with central pain.

SETTING

Pain Clinic, Osaka University Medical Hospital, Osaka, Japan.

PATIENT

A patient with central pain after loss of his left upper extremity.

INTERVENTIONS

A 50-mg dose of intravenous amobarbital, which produced a plasma concentration of 2.5-4.0 microg/ml, was effective in reducing the central pain. Subsequently, doses of 300-400 mg/day were administered orally; these succeeded in achieving similar plasma concentration levels.

RESULTS AND CONCLUSIONS

Oral administration of barbiturate did not alleviate central pain, even when the plasma concentration was the same as the effective level in intravenous use. Pharmacokinetic and pharmacodynamic factors more complex than simple plasma concentrations may be involved in producing the difference in the effects.

Helicobacter pylori, neutrophils, interleukins, and gastric epithelial proliferation

Infection of Helicobacter pylori causes chronic gastritis and plays an important role in the pathogenesis of gastroduodenal ulceration. H. pylori has also been suggested to be involved in the genesis of adenocarcincoma and MALT lymphoma of the stomach. H. pylori infection is associated with increased gastric epithelial proliferation, which can be reversed by a successful eradication of the organism. Although the mechanisms of increased gastric epithelial proliferation is not known, the enhanced epithelial proliferation is important in developing gastric carcinoma. Whether or not H. pylori de nove stimulates gastric epithelial proliferation is controversial, but gastric infection with H. pylori activates a mucosal inflammatory response by consisting of large numbers of polymorphonuclear and mononuclear cells, that also includes expression of various cytokines including interleukin-8. We review the mechanisms of H. pylori in enhanced gastric epithelial cell proliferation and cytokines in patients with H. pylori infection.

Clinical efficacy of lactulose in cirrhotic patients with and without subclinical hepatic encephalopathy

Seventy-five cirrhotic patients with hyperammonemia in the past or at the time of the study were randomly divided into two groups (treated with lactulose or nontreated) in 14 hospitals in Japan. Thirty-six cirrhotic patients were diagnosed as having subclinical hepatic encephalopathy (SHE), and 39 were diagnosed as non-SHE. SHE was diagnosed when the results of all three of the quantitative psychometric tests used (number connection test, and symbol digit and block design tests of the Wechsler adult intelligence scale [revised]) were abnormal as compared with age-matched normal values. The mean number of abnormal psychometric test results and the prevalence of SHE were used for a quantitative evaluation of the efficacy of the lactulose treatment. Twenty-two of the SHE patients were treated with lactulose (45 mL/d) for 8 weeks, and the other 14 SHE patients did not receive lactulose. In the SHE patients administered lactulose, the results of the quantitative psychometric evaluation were significantly improved at 4 and 8 weeks after the beginning of the lactulose administration. The SHE had disappeared in 10 (50%) of the 20 treated patients at week 8, but it persisted in 11 (85%) of the untreated 13 patients. We concluded that lactulose treatment in cirrhotic patients with SHE is effective with respect to psychometric tests.

Quantitative reverse transcription-PCR-HPLC for nerve growth factor mRNA using a deletion RNA as an internal standard

We have developed a convenient method for the routine measurement of the absolute amount of nerve growth factor (NGF) mRNA in tissue samples. The method consists of RNA extraction, amplification by reverse transcription-PCR and detection by high-performance liquid chromatography. The addition of a deletion mutant RNA to tissue samples as an internal standard enabled correction for RNA recovery during extraction, and the target mRNA and the internal standard were both amplified with the same PCR primers. The conditions were optimized so that the procedure was conducted in the region where the calibration curve was linear, thereby allowing high reproducibility and reliability. The method was applied to the measurement of NGF mRNA in tissues such as skin and skeletal muscle, where the levels are too low to be easily detected by Northern blotting analysis: skin, 14.1 +/- 4.6 fg/mg tissue and skeletal muscle, 11.0 +/- 2.2 fg/mg tissue (mean +/- SD, n = 10). The coefficient of variation of this method was less than 2.8%. This approach should also be applicable to the routine assay of the absolute amount of other mRNAs present at low levels in tissues.

Nosocomial spread of cephem-resistant Escherichia coli strains carrying multiple Toho-1-like beta-lactamase genes

Escherichia coli HKY56, which demonstrated resistance to various beta-lactams except carbapenems, was isolated from the throat swab of an inpatient in 1994. Conjugal transfer of cephem resistance from HKY56 to E. coli CSH2 was not successful. Three cefotaxime-resistant E. coli clones harboring plasmid pMRE001, pMRE002, or pMRE003, each of which carried a 3.4-, 5.8-, or 6.2-kb EcoRI fragment insert, respectively, were obtained from HKY56. Although restriction analysis suggested their different origins, these clones showed similar profiles of resistance to various beta-lactams. The sequence of 10 amino acid residues at the N terminus of beta-lactamase purified from E. coli HB101(pMRE001) was identical to that of Toho-1. This Toho-1-like beta-lactamase-1 (TLB-1) was able to hydrolyze cefoperazone and cefotaxime efficiently, but it failed to hydrolyze cephamycins. A Toho-1-specific DNA probe was hybridized with three distinct EcoRI fragments derived from the chromosomal DNA of strain HKY56, and these fragments corresponded to DNA inserts carried by pMRE001, pMRE002, and pMRE003, respectively. PCR and Southern hybridization analysis suggested that all six cephem-resistant E. coli strains, strains HKY273, HKY285, HKY288, HKY305, HKY316, and HKY335, which were isolated in 1996 at the same hospital where strain HKY56 had been isolated, also possessed multiple Toho-1-like beta-lactamase (TLB) genes, and the hybridization patterns obtained with the Toho-1-specific probe were quite similar among these six isolates. The DNA fingerprinting patterns observed by pulsed-field gel electrophoresis revealed that among the E. coli isolates tested, all isolates except HKY56 possessed a similar genetic background. These findings suggested that E. coli strains that carry chromosomally multiplied TLB genes may have been proliferating and transmitted among patients in the same hospital.

Clinical efficacy of lactulose in cirrhotic patients with and without subclinical hepatic encephalopathy

Seventy-five cirrhotic patients with hyperammonemia in the past or at the time of the study were randomly divided into two groups (treated with lactulose or nontreated) in 14 hospitals in Japan. Thirty-six cirrhotic patients were diagnosed as having subclinical hepatic encephalopathy (SHE), and 39 were diagnosed as non-SHE. SHE was diagnosed when the results of all three of the quantitative psychometric tests used (number connection test, and symbol digit and block design tests of the Wechsler adult intelligence scale [revised]) were abnormal as compared with age-matched normal values. The mean number of abnormal psychometric test results and the prevalence of SHE were used for a quantitative evaluation of the efficacy of the lactulose treatment. Twenty-two of the SHE patients were treated with lactulose (45 mL/d) for 8 weeks, and the other 14 SHE patients did not receive lactulose. In the SHE patients administered lactulose, the results of the quantitative psychometric evaluation were significantly improved at 4 and 8 weeks after the beginning of the lactulose administration. The SHE had disappeared in 10 (50%) of the 20 treated patients at week 8, but it persisted in 11 (85%) of the untreated 13 patients. We concluded that lactulose treatment in cirrhotic patients with SHE is effective with respect to psychometric tests.

Clinical efficacy of lactulose in cirrhotic patients with and without subclinical hepatic encephalopathy

Seventy-five cirrhotic patients with hyperammonemia in the past or at the time of the study were randomly divided into two groups (treated with lactulose or nontreated) in 14 hospitals in Japan. Thirty-six cirrhotic patients were diagnosed as having subclinical hepatic encephalopathy (SHE), and 39 were diagnosed as non-SHE. SHE was diagnosed when the results of all three of the quantitative psychometric tests used (number connection test, and symbol digit and block design tests of the Wechsler adult intelligence scale [revised]) were abnormal as compared with age-matched normal values. The mean number of abnormal psychometric test results and the prevalence of SHE were used for a quantitative evaluation of the efficacy of the lactulose treatment. Twenty-two of the SHE patients were treated with lactulose (45 mL/d) for 8 weeks, and the other 14 SHE patients did not receive lactulose. In the SHE patients administered lactulose, the results of the quantitative psychometric evaluation were significantly improved at 4 and 8 weeks after the beginning of the lactulose administration. The SHE had disappeared in 10 (50%) of the 20 treated patients at week 8, but it persisted in 11 (85%) of the untreated 13 patients. We concluded that lactulose treatment in cirrhotic patients with SHE is effective with respect to psychometric tests.