Cloning and expression of the gene for hydroxypyruvate reductase (D-glycerate dehydrogenase from an obligate methylotroph Hyphomicrobium methylovorum GM2

The gene encoding hydroxypyruvate reductase, catalyzing the asymmetric reduction of hydroxypyruvate to D-glycerate, and its flanking regions were isolated from a methylotrophic bacterium, Hyphomicrobium methylovorum GM2. Nucleotide sequencing of the recombinant plasmids revealed that the hydroxypyruvate-reductase gene codes for the 322-amino-acid protein with calculated molecular mass 35,726 Da. The sequence was confirmed by sequencing the intact enzyme and peptides obtained by digestion of the enzyme with Achromobacter proteinase I. The amino acid sequence of the enzyme showed similarity to members of the D-isomer-specific 2-hydroxyacid dehydrogenase family. The recombinant plasmid, which was constructed by ligation of the cloned gene and an expression vector pKK223-3, was introduced into Escherichia coli HB101. The recombinant enzyme purified from the transformed E. coli cells was indistinguishable from the enzyme isolated from H. methylovorum GM2 by immunological and enzymological analyses.

The Accuracy of Micro-molds Produced by a UV Laser Induced Polymerization

This research work deals with the development of a simple and practical method for manufacturing metallic micromachine parts on the order of 0.01–1.0 mm in size. In this method, an ultraviolet laser beam is irradiated onto the surface of a liquid photopolymer material through a mask. The irradiated pattern is then developed to produce a solidified photopolymer mold. Finally, the metallic part is made by an electroforming process. This paper deals with the first process, the making of the photopolymer mold. At first, the accuracy of the mold is estimated by applying the theories of diffraction and absorption of light. Next, the accuracy is examined experimentally. The results show an accuracy of ± 1 μm can be obtained when a proximity transfer of 10 μm between the mask and the photopolymer surface is used. By stacking thin films, thick and high aspect ratio molds with a reasonably high accuracy are made.

Echography of inferior vena cava for estimating fluid removed from patients undergoing hemodialysis

Twenty-eight chronic hemodialysis patients were studied, and 118 consecutive measurements of the diameter of their inferior vena cava (VCD) were performed with ultrasonography. There was a significant correlation between the percent change in VCD in the expiratory phase (delta VCD-E%) and the percent change of in body weight (delta BW%). The average VCD-E in predialysis was 10.7 +/- 3.2 mm/m2 and this value decreased gradually following ultrafiltration and reached a minimal diameter of 7.5 +/- 2.8 mm/m2 in postdialysis. Three cases developed hypotension due to fluid removal. Their VCD-E value showed a rapid reduction below 7.5 mm/m2 in the early phase of hemodialysis, then maintained a plateau. The hypotension was thought to be caused by hypovolemia due to overdehydration. We conclude that VCD-E was an effective indicator for determining the volume of fluid removed, and the dry weight was attained safely and correctly by means of undergoing ultrafiltration to keep the value of VCD-E above 7.5 +/- 2.8 mm/m2.

Prevalence of human herpesvirus 6 variants A and B in patients with chronic fatigue syndrome

Peripheral blood mononuclear cells collected from 13 patients with chronic fatigue syndrome and 13 healthy controls were analyzed for the presence of human herpesvirus 6 (HHV-6) DNA by variant-specific polymerase chain reaction and dot blot hybridization. HHV-6 DNA was detected in 7 of 13 (53%) patients, and of those 7 patients, 4 were positive for HHV-6 variant A DNA and 3 were for variant B. No HHV-6 DNA was detected in the controls. Serum antibody titers to the late antigen and antibody prevalence to the early antigen of HHV-6 were significantly higher in the patient group. These results suggest active replication of HHV-6 in patients with chronic fatigue syndrome.

[Hodgkin's disease with a giant thymic cyst]

An asymptomatic 26-year-old male was admitted to our hospital for examination of an abnormal mediastinal shadow on chest X-ray. Chest CT showed a large mass in the anterior mediastinum with marked para-aortic lymph node enlargement. The mass consisted mostly of multiloculated low-density areas surrounded by a rim of enhancing parenchymal tissue. Both the cystic tumor and surrounding lymph nodes were resected. The tumor measured 18 x 10 x 2 cm and contained about 450 ml of straw colored fluid. Pathological examination revealed a thymic cyst, the wall of which was composed of Hodgkin's lymphoma cells and nodular sclerotic lesions containing many lacunar cells and Reed-Sternberg cells.

[Simultaneous bilateral testicular tumors: a case report]

We report a case of bilateral simultaneously-occurring testicular tumors. A 43-year-old man was admitted to our clinic with a complaint of right inguinal pain in May 1992. Under the diagnosis of bilateral testicular neoplasms, bilateral high orchiectomy was performed. Histological examination revealed typical seminoma of bilateral testes. The patient was diagnosed with stage IIIO seminoma, and he was treated with combination chemotherapy (PVB). No evidence of disease has been seen after chemotherapy.

Seroepidemiology of hepatitis C virus infection in Japan and HCV infection in haemodialysis patients

Since January 1990, Japanese Red Cross Blood Centres have introduced hepatitis C virus screening with a first-generation ELISA. From April to December 1992, approximately 0.98% among 10,905,489 blood donations screened by a second-generation assay were anti-HCV-positive in all Japan. Seropositivity of anti-HCV increased with the age and serum transaminase value in both sexes. In blood donors having a history of transfusion, the anti-HCV reactive rate was 7.4%. The results of the study made by the Japanese Red Cross Non-A, Non-B Hepatitis Research Group show the effectiveness of implementation of HCV screening to prevent posttransfusion hepatitis. Consecutive haemodialysis patients with chronic renal failure are at risk for infection by a variety of blood-borne agents transmitted within dialysis units. Because of their immunocompromised state, they frequently also have an unusual susceptibility to a variety of nosocomial infections, such as HBV, HCV, and HTLV-I. We tested the prevalence of anti-HCV in 1423 (848 males and 575 females) haemodialysis patients from 18 hospitals in Kumamoto Prefecture, Japan, using the Ortho first generation anti-HCV screening assay. There were 316 patients (22.2%) positive for HCV antibodies. The second-generation test was positive in most haemodialysis patients who were reactive to the first-generation assay. The prevalence of HCV infection increased with the duration of haemodialysis, yet there was a high frequency of HCV seropositivity even without blood transfusion. Acquisition of HCV in dialysis patients could be explained by HCV infection within the unit other than by blood (all haemodialysis are done with disposable kits, syringes, and needles), by secondary HCV infection after the immunodeficiency of haemodialysis, or by HCV infection of the kidney or glomerular deposition of immune HCV/anti-HCV complexes leading to chronic renal failure (as with HBV infection of the liver and kidney.

Establishment of a human small cell lung cancer cell line producing a large amount of anti-diuretic hormone

A new cancer cell line (Lu-165) producing a large amount of anti-diuretic hormone (ADH, 2.8 micrograms/g protein) was established from a 50-year-old small cell lung cancer patient presenting with a syndrome of inappropriate anti-diuretic hormone secretion. These cells grew well in serum-supplemented medium and during more than 100 passages they continued producing a large amount of this hormone. This cell line will be a useful tool for studies of the biochemistry and pathology of ADH-producing cancer.

Hepatitis C virus particle detected by immunoelectron microscopic study

To clarify the morphology of hepatitis C virus (HCV), an indirect immunogold electron microscopic study was carried out on two plasma samples with high HCV RNA titres using polyclonal and monoclonal antibodies specific to the putative HCV envelope protein. Spherical virus-like particles, 55 to 65 nm in diameter with spike-like projections, were found in 1.14 to 1.16 g/ml fractions after sucrose density gradient centrifugation. These particles were found only in HCV-infected blood donors and had morphological features similar to those of flaviviruses. Moreover, these particles specifically reacted with the polyclonal and monoclonal antibodies to the putative HCV envelope protein. This is the first known report in which the morphology of the HCV particle is clearly shown.

[Experimental study of differentiation between tumor and inflammation using MR imaging: correlation between VX2 tumors and croton oil induced inflammation in the rabbit's femoral muscle]

We evaluated the various Magnetic Resonance (MR) sequences for differentiation between tumors and inflammation. Experimental models of rabbit's tumors (VX2) and inflammation induced by croton oil in the femoral muscle were used for this evaluation. Both types of lesions presented a high intensity area on T2-weighted and heavy T2-weighted images. An inflammatory lesion was revealed with iso-/low intensity area and tumors were defined as high signal lesions on Sinc saturation fat suppression T1-weighted, standard T1-weighted and fat suppression T1-weighted images by the 3 Point dixon method. T1, T2 values of tumor and inflammatory lesions were also measured. The T1 value of the tumors was 1186 +/- 58 msec (n = 5) and that of the inflammatory lesion was 1097 +/- 40 msec (n = 3). The T2 value of the tumors was 71 +/- 13 msec (n = 5) and that of the inflammatory lesions was 70 +/- 5.5 msec (n = 3). There were no significant differences between both the T1 and T2 values. Calculated relative proton density was 0.69 +/- 0.14 (n = 4) in the tumors, and 0.42 +/- 0.12 (n = 3) in the inflammatory lesions. A statistical difference (p < 0.05) was found in both value. These results suggest that a T2-weighted image is not useful for differentiation between tumors and inflammation, and a T1-weighted image might be useful for such differentiation. This phenomenon is related to the difference of the proton density.

Significance of specific antibody assay for genotyping of hepatitis C virus

Group I and II hepatitis C virus genotypes were determined by a newly developed serological genotyping assay. This assay detected antibodies against group-specific recombinant proteins in the putative NS4 protein region (amino acid no. 1676-1760) by an enzyme-linked immunosorbent assay. This region of the hepatitis C virus peptide has many group-specific amino acids; fewer than 50% of these amino acids are identical between groups I and II. Genotypes determined by the serological genotyping assay were compared with those determined by a method in which the polymerase chain reaction was used in 91 chronic hepatitis patients. The group-specific polymerase chain reaction was performed within the genome region corresponding to the putative NS5 protein, where the group II hepatitis C virus genome is 57 nucleotides longer than that of group I. Among 91 chronic hepatitis C patients who had positive results in the second-generation hepatitis C virus antibody (core and NS3 region) assay, hepatitis C virus RNA was detected in 80 patients by polymerase chain reaction in the 5' untranslated region and in 78 patients by this group-specific polymerase chain reaction. As a result, in 76 of 91 patients (84%) genotypes determined by the serological genotyping assay showed complete agreement with those determined by the group-specific polymerase chain reaction, and none of the patients revealed a group opposite to that of hepatitis C virus genotype. The detection rate of the serological genotyping assay (89 of 91; 98%) was even higher than that of the polymerase chain reaction assay (78 of 91; 86%).(ABSTRACT TRUNCATED AT 250 WORDS)

[Stereochemistry of benzanilides and N-methylbenzanilides]

Conformations of benzanilide , N-methylbenzanilide and those with a methyl group(s) ortho to the amide bond in solution and in the crystal have been studied. N-Methylbenzanilide exists in cis-amide (E) form in the crystal. In CDCl3 solution, cis-amide form is also predominant (99%), while benzanilide exists in trans-amide (Z) form in the crystal and in solution. In the crystal, all the methyl-substituted benzanilides exist in trans-amide conformation and the introduction of an ortho-methyl group(s) makes the interplanar angles of the aromatic rings and the amide group (Aramide) larger. N-Methylbenzanilides exist in cis form in the crystal except the compound which has four methyl groups ortho to the amide bond. For the N-methylbenzanilides, the effects of introduction of one or two ortho-methyl groups on the dihedral angles of Ar-amide are smaller than that for the secondary benzanilides. In solution, benzanilides exist exclusively in trans conformation except for the compound 12 which has a minor cis conformer (3%) in CDCl3, whereas N-methylbenzanilides exist in equilibrium between the major cis-form and the minor trans-form. The tetramethyl derivative exists in trans conformation in solution as observed in the crystal. For N-methylbenzanilides, an introduction of a methyl group(s) ortho to the amide bond seems to destabilize the cis-amide conformation in solution, resulting in an increased ratio of the trans-amide conformation.

Production of endothelin-1 and thrombomodulin by human pancreatic cancer cells

Analysis of bioactive substances produced by cancer cells is one approach to understanding the biological features of human cancer. One of these bioactive substances is endothelin (ET)-1, a peptide with potent vasoconstrictive activity produced by vascular endothelial cells. We have previously reported the production of ET-1 by several types of human cancer, especially pancreatic cancer cells. To elucidate whether these cancer cells might share biological characteristics with vascular endothelial cells, we investigated the production of three ET isoforms in pancreatic cancer cells, using a specific radioimmunoassay. Further, we also investigated whether these cells produce thrombomodulin (TM), another product of endothelial cells functioning as a modulator of procoagulant activity. ET-1 was detected in 11 of 12 pancreatic cancer cell lines (92%) while ET-2 and ET-3 were detectable in only one cell line. Gel filtration analysis confirmed the presence of ET-1. Moreover, TM was detected in the cell lysates of 11 of the 12 cell lines (92%) and it was released into the culture medium in the majority (58%) of these cell lines. TM mRNA was also detected in these cells. In addition, TM was demonstrated immunocytochemically along the cell surface. These results suggest that pancreatic cancer cells share two characteristics with endothelial cells: the production of ET-1 and TM.

[Xenon-133 rCBF SPECT by newly designed bolus inhalation method]

Single photon emission computed tomography (SPECT) with 133Xe gas inhalation method enables measurement of regional cerebral blood flow (rCBF) quantitatively. But this method is inferior to the method with 99mTc-HMPAO or 123I-IMP in the quality of images. Efficient administration of 133Xe gas more than usual is supposed to improve quality of SPECT images. In this study we designed bolus inhalation method, a new method to efficiently administer 133Xe gas of usual dose (1,850 MBq), and examined its fundamental aspects and clinical feasibility. The method was initiated by bolus administration of 133Xe gas synchronously in inspiration phase via a small tube connected to a mouthpiece and was followed by steady breathing of the gas in a closed circuit with a spiro-bag. Introduction of this method provided almost twofold increase in count ratio at the head in comparison with a conventional inhalation method. Consequently, considerable improvement in the quality of rCBF images was achieved by optimization of a reconstruction filter of SPECT.

Intracranial vertebral artery dissection in Wallenberg syndrome

PURPOSE

To assess the prevalence of vertebral artery dissection in Wallenberg syndrome.

METHODS

Sixteen patients (12 men, 4 women; mean age at ictus, 51.6 years) with symptoms of Wallenberg syndrome and an infarction demonstrated in the lateral medulla on MR were reviewed retrospectively. The study items were as follows: (a) headache as clinical signs, in particular, occipitalgia and/or posterior neck pain at ictus; (b) MR findings, such as intramural hematoma on T1-weighted images, intimal flap on T2-weighted images, and double lumen on three-dimensional spoiled gradient-recalled acquisition in a steady state with gadopentetate dimeglumine; (c) direct angiographic findings of dissection, such as double lumen, intimal flap, and resolution of stenosis on follow-up angiography; and (d) indirect angiographic findings of dissection (such as string sign, pearl and string sign, tapered narrowing, etc). Patients were classified as definite dissection if they had reliable MR findings (ie, intramural hematoma, intimal flap, and enhancement of wall and septum) and/or direct angiographic findings; as probable dissection if they showed both headache and suspected findings (ie, double lumen on 3-D spoiled gradient-recalled acquisition in a steady state or indirect angiographic findings); and as suspected dissection in those with only headache or suspected findings.

RESULTS

Seven of 16 patients were classified as definite dissection, 3 as probable dissection, and 3 as suspected dissection. Four patients were considered to have bilateral vertebral artery dissection on the basis of MR findings.

CONCLUSIONS

Vertebral artery dissection is an important cause of Wallenberg syndrome.