Exocytosis relating proteins in the nervous system

Hypothetical models of the molecular mechanism underlying presynaptic exocytosis were reviewed and the exocytosis relating proteins were categorized into four groups: docking, anchoring, fusion and inhibiting proteins. HPC-1/syntaxin, an axonal membrane protein, was classified as an anchoring protein, not as the vesicle docking protein, because electron microscopic study using cryoimmunogold technique revealed that HPC-1 distributed over the entire axonal membrane, where the synaptic vesicles were not 'docked' to the membrane. Since selective toxin or antibody against HPC-1 affected exocytosis, HPC-1 might be a necessary component for the exocytosis, but HPC-1 by itself seemed to have no ability to bind synaptic vesicles to the membrane in vivo. The molecular mechanism for Ca-dependent, rapid exocytosis and possible roles of the exocytosis relating proteins in the neurite morphogenesis are discussed.

Cerebral protective effects of VA-045, a novel apovincaminic acid derivative, in mice

The cerebral protective effects of VA-045, a novel apovincaminic acid derivative, were investigated in mice under conditions of normobaric hypoxia, histotoxic anoxia by potassium cyanide (KCN), and complete ischemia. VA-045 and thyrotropin releasing hormone (TRH) showed a significant protective effect on normobaric hypoxia. The duration of action of the protective effect of VA-045 was longer than that of TRH. VA-045 but not TRH significantly prolonged the survival time following administration of KCN. VA-045 and TRH showed a positive effect on complete ischemia, and the duration of the protective effect of VA-045 was longer than that of TRH. Beneficial effects of VA-045 for treating cerebral hypoxia, anoxia and ischemia will be discussed.

Ventilation-perfusion inequality and diffusion impairment in acutely injured lungs

To assess the significant role of diffusion impairment and its unequal distribution in acutely injured lungs with alveolar flooding, oleic acid was intravenously injected into twenty-five mongrel dogs. The animals were divided into two groups, A and B. 0.1% CO in air was delivered, as an inspired gas, to the animals of group A. Simultaneously, saline containing a trace amount of six foreign inert gases was infused through a peripheral vein. While allowing the animals in group B to breathe air, saline containing ethylene, acetylene and freon 22 was infused. After injection of oleic acid, group A revealed increase in intrapulmonary shunt accompanied by a marked broadening of ventilation-perfusion (VA/Q) and diffusing capacity-perfusion (G/Q) distributions. A considerable amount of total cardiac output was received by the lung areas with low G/Q ratios where significant diffusion limitation was predicted to occur. Group B showed that excretion of freon 22 (gas with lower diffusivity) in injured lungs was considerably distorted as compared to those of ethylene and acetylene (gases with higher diffusivities), again ascertaining the importance of diffusion limitation in lungs with exudate in alveolar regions.

Increased serum levels of C-terminal parathyroid hormone-related protein in different diseases associated with HTLV-1 infection

We analyzed the serum levels of C-terminal parathyroid hormone-related protein (C-PTHrP) in asymptomatic carriers of human T lymphotropic virus type 1 (HTLV-1) and patients with three HTLV-1 related diseases; adult T-cell leukemia (ATL), HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP) and HTLV-1 uveitis (HU). Serum C-PTHrP levels were significantly elevated in HTLV-1-infected individuals, irrespective of whether they were symptomatic or asymptomatic, when compared with that of the seronegative controls. In ATL patients, a good correlation was demonstrated between the serum C-PTHrP level and serum calcium or lactic dehydrogenase (LDH) level. Thus the elevated serum C-PTHrP level could be a characteristic marker of HTLV-1 carrier state, and the determination of its level in ATL patients could be useful for the assessment of the prognosis and as one of the tumor markers. The determination of the serum level of C-PTHrP in various stages of the HTLV-1 carrier state would help to understand the mechanism of the development of hypercalcemia in ATL.

Analysis of cell surface antigens using anti-rat hepatocyte monoclonal antibodies, particularly HAM 1

The expression of antigens on rat hepatocytes was examined by immunoelectron microscopy using monoclonal antibody HAM 1. The antigen recognized by HAM 1 was expressed mainly on both sinusoidal and bile-canalicular faces and only sparsely on the contiguous face. All rat hepatoma cell lines examined were intensely labeled with HAM 1, but poorly labeled with HAM 3, HAM 4, and HAM 5, as revealed by flow cytofluorometry and radioimmunoassay. Expression levels of HAM 1 antigen on the AH 44 hepatoma cell line similar to the degree seen in normal liver were demonstrated by radioimmunoassay. HAM 1 antigen was also expressed weakly on lymphocytes, thymocytes, and some bone marrow cells, but not on red blood cells, and differed from the MHC class I antigen recognized by HAM 2 and OX 18. Significant amounts of cell surface antigens recognized by all the monoclonal antibodies (HAM 1-HAM 5) were confirmed by radioimmunoassay on the cell surface of primary cultured hepatocytes. These results suggest that the rat hepatoma cell lines employed are different from normal hepatocytes, that primary cultured hepatocytes are more similar to normal hepatocytes in the degree of expression of their cell surface antigens, and that HAM 1 antigen appears to be a significant antigen on both normal and transformed hepatocytes.

[The correlation between the MICs deduced from Showa disk method and the MICs determined by micro-dilution method]

Disc diffusion technique is useful to routine drug susceptibility testing for bacteria in clinical laboratories because of the advantages on simplicity and cost. Kirby-Bauer (KB) method recommended by NCCLS is using widely as a standard method of disk diffusion test, and simply categorize microorganisms as being susceptible, moderately susceptible, intermediate or resistant to different antimicrobial agents by the use of break point. In the determination of breakpoints, the relationship between MICs and clinical results and pharmacokinetics parameters (Cmax, T1/2 and AUC) are significantly considered. However, there are variance of pharmacokinetics among a race, moreover, breakpoint is not yet established in Japan. In report to doctor from clinical laboratory, the MIC might be better than that by breakpoint since there are such problems of breakpoint. Showa disk was developed as mono-disk method being able to deduce MIC from the linear regression between MIC and zone diameter. Therefore, it is thought that Showa disk is one of valuable methods for the routine drug susceptibility testing for bacteria in Japan. There is one problem, which is that MIC deduced by Showa disk is based on the relationship with agar dilution method although the determination method of MIC is going to turn into micro-dilution method, so we compared the MICs deduced from zone diameter of Showa disk method with the MICs determined by broth micro-dilution method by using a challenge set of 110 gram-positive and gram-negative bacteria for 7 antimicrobial agents. The total agreement of MIC within 1-log2 dilution difference was 77% and the correlation coefficient was 0.929. As results, a good relationship was obtained except the results of tetracycline and ofloxacin for beta-lactamase non-producing H. influenzae, and ceftizoxime for E. coli, and K. pneumoniae.

Further evidence of no linkage between schizophrenia and the dopamine D3 receptor gene locus

The dopamine hypothesis of schizophrenia proposed that dopaminergic pathways are involved in the etiology of the disease. In particular, interest among psychiatrists has focused on the D2 receptor because of its affinity to antipsychotic drugs. Recently a new dopamine receptor gene has been cloned, and named the dopamine D3 receptor. The D3 receptor is a potential site for antipsychotic drug action and may be involved in the pathophysiology of schizophrenia. We have carried out a linkage study between the susceptibility gene for schizophrenia and polymorphism of the dopamine D3 receptor gene in two Japanese pedigrees. The LOD scores were negative for all genetic models and for all affective status at a recombination fraction theta = 0. Linkage of DRD3 has been excluded for the model 1 (dominant model) and the model 3 (recessive model). The LOD score was -3.43 at theta = 0 for model 1 (dominant model) and broad definition of affected status. These results were consistent with previous studies.

Correlation between the in vitro and in vivo effects of fourteen beta-lactam compounds in mice with systemic infection

The in vivo effect of 14 beta-lactam compounds was compared with the in vitro effect in mice systemically infected with Pseudomonas aeruginosa E7 or Klebsiella pneumoniae 3K-25. The microorganisms were inoculated intraperitoneally, and the in vivo effect of the drug was expressed as the median effective dose (ED50) determined by subcutaneous administration of the drug 1 h after the inoculation. In the mice infected with P. aeruginosa, the ability of the drug to kill the bacteria in a short time (killing activity) was markedly correlated with the ED50 (r = -0.704), but there was no correlation with the maximum concentration, half-life or area under the curve of the drug. The coefficient of multiple correlation of the ED50 with killing activity+time above the minimum bactericidal concentration (MBC) was 0.824 (contribution rate, 67.9%). In the mice infected with K. pneumoniae, the killing activity was highly correlated with MBC (r = 0.899), and the coefficient of multiple correlations with MBC+time above MBC was 0.919 (contribution rate, 84.4%). These results suggest that beta-lactam compounds have strong bactericidal activity in mice with systemic infection and that drugs with a long time above MBC are effective for this condition.

Operative treatment of syndesmotic disruptions without use of a syndesmotic screw: a prospective clinical study

A new protocol for the selected omission of transsyndesmotic fixation in Weber class C ankle fractures was prospectively evaluated in 21 consecutive patients. As proposed in a previous cadaveric study (J. Bone Joint Surg., 71A:1548-1555, 1989), the protocol suggested that transsyndesmotic fixation was not required if (1) rigid bimalleolar fracture fixation was achieved or (2) lateral without medial fixation was obtained (i.e., with accompanying deltoid tears) if the fibular fracture was within 4.5 cm of the joint. According to this protocol, only 3 of 21 patients (14%) required transsyndesmotic fixation. Ten of the patients who did not receive transsyndesmotic fixation underwent pronation-external rotation stress radiographs in a fashion analogous to the previous cadaveric study. At 1- to 3-year follow-up, no stress (N = 10) or static view (N = 18) widening of the mortise or syndesmosis was seen in any patient, which supports (with the above guidelines) a limited, rather than routine, use of supplemental transsyndesmotic fixation. Clinical results from this prospective study seem to substantiate previously proposed biomechanical guidelines for the selected omission of transsyndesmotic fixation. Given these guidelines, transsyndesmotic fixation was unnecessary in many cases and the need can be determined before surgery by assessing the integrity of the deltoid ligament and level of the fibular fracture.

Subtype analysis of HTLV-1 in patients with HTLV-1 uveitis

The hypothesis that HTLV-1 uveitis, a recently identified disease entity associated with human T-cell leukemia virus type I (HTLV-1), is caused by a specific subtype of the virus was tested. The nucleotide sequences of the long terminal repeat of HTLV-1 from five patients with HTLV-1 uveitis (HU) and four with adult T-cell leukemia were phylogenetically analyzed. Our results showed that both subtypes which had been identified in Japan were associated with HU, indicating that there was no difference in pathogenicity between these phylogenetic subtypes. One of the subtypes was more frequently isolated in Okinawa than in Kyushu, suggesting a bias in the prevalence of each subtype among the inhabitants of these two areas of Japan.

[Bactericidal activities of isepamicin and ofloxacin against Pseudomonas aeruginosa evaluated using an in vitro pharmacokinetic simulation system]

Bactericidal activities of isepamicin and ofloxacin against Pseudomonas aeruginosa E7 were examined using an in vitro computer programmed pharmacokinetic simulation system. Concentration of the drugs simulated the pharmacokinetic data obtained in healthy human adult subjects after 200 mg or 400 mg I.M. administration of isepamicin (ISP), and 300 mg P.O. administration of ofloxacin (OFLX). P. aeruginosa cell counts were depressed by ISP or OFLX to -4 log -(-)5 log levels of magnitude below the initial cell counts. The time required in recovery of cell counts to the initial level after treatment with ISP (200 mg) was longer than that after OFLX (300 mg) treatment. An excellent synergistic effect was observed between ISP and OFLX.

[High oxygen breathing improves inhomogeneities of ventilation-perfusion distributions in acutely injured lungs]

Using twenty-five mongrel dogs either with or without alveolar flooding induced by oleic acid administration, the effects of high oxygen breathing (60% O2) on ventilation--perfusion (VA/Q) distributions in the lungs were systematically investigated. VA/Q distributions were examined by multiple inert gas elimination technique, from which the VA/Q values describing mean positions of perfusion (Q) and ventilation (VA) distributions against the VA/Q axis were calculated (mean Q and mean VA). As the first measure of dispersion for VA/Q distribution, the log standard deviation was estimated (log SD (Q) and logSD (VA)). As the second measure of dispersion, the area under the curve, constructed by plotting inert gas arterial-to-alveolar partial pressure differences as a function of blood-gas partition coefficient, was calculated (aAD area). High oxygen breathing slightly enhanced the dispersion of VA/Q distributions in the normal dogs but decreased that in the dogs injured with oleic acid. Therefore, we concluded that high oxygen breathing worsened the inhomogenieties of VA/Q distributions in normal lungs but did improve those in acutely injured lungs.

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.