Self-maintenance and self-reproduction in an abstract cell model

Living cells must maintain their membranes by active metabolism. The membrane is not static but a dynamic structure that has evolved along with its internal reactions. When we reflect on the emergence and evolution of primitive cells, we should not forget the mutual dependency between membranes and metabolic cycles inside the cell. In this paper, we present a simple abstract model of the self-maintaining cell. A metabolic cycle will produce a self-assembling membrane that will enclose the metabolic cycle. We show that a self-maintaining cell has the potential to reproduce itself spontaneously. Further, we have demonstrated two different ways of cellular reproduction depending on the mobility of chemicals. In the first case, a cell releases autocatalytic chemicals that create new cells outside the mother cell. In the second case, a cell grows larger and divides itself into daughter cells by creating a new internal dividing membrane.

SLAM (CDw150) is a cellular receptor for measles virus

Measles virus continues to be a major killer of children, claiming roughly one million lives a year. Measles virus infection causes profound immunosuppression, which makes measles patients susceptible to secondary infections accounting for high morbidity and mortality. The Edmonston strain of measles virus, and vaccine strains derived from it, use as a cellular receptor human CD46 (refs 3, 4), which is expressed on all nucleated cells; however, most clinical isolates of measles virus cannot use CD46 as a receptor. Here we show that human SLAM (signalling lymphocyte-activation molecule; also known as CDw150), a recently discovered membrane glycoprotein expressed on some T and B cells, is a cellular receptor for measles virus, including the Edmonston strain. Transfection with a human SLAM complementary DNA enables non-susceptible cell lines to bind measles virus, support measles virus replication and develop cytopathic effects. The distribution of SLAM on various cell lines is consistent with their susceptibility to clinical isolates of measles virus. The identification of SLAM as a receptor for measles virus opens the way to a better understanding of the pathogenesis of measles virus infection, especially the immunosuppression induced by measles virus.

Lung abscess caused by Paecilomyces lilacinus

We report the case of a 57-year-old man who was referred to our department for further investigation of an abnormal chest shadow. Radiography on admission demonstrated a coin lesion in the right hilum. To make a final diagnosis, right middle lobectomy was performed and the mass was revealed to be a fungal abscess. Further examination confirmed that the fungus was Paecilomyces lilacinus. This is the first reported case of lung abscess caused by P. lilacinus in an otherwise healthy person.

Different turnover rate of hepatitis C virus clearance by different treatment regimen using interferon-beta

BACKGROUND/AIM

Since patients with high viral load and HCV subtype 1b are known to respond poorly to interferon (IFN) therapy, the viral dynamics of HCV RNA after initiation of interferon therapy were examined in the present study with respect to two different administration regimens, once vs. twice a day.

METHODS

Twenty-two patients with chronic hepatitis C confirmed by liver biopsy and with >1 Meq/ml of HCV RNA and HCV subtype 1b were randomly assigned to two different IFN administration regimens (6 million units of IFN once a day or 3 million units of IFN twice a day), and the serum HCV RNA level was serially measured.

RESULTS

Graphs of HCV RNA levels vs. treatment time showed an initial rapid fall, followed by a slower clearance phase. Fitting the data to a model for HCV decay proposed by Neumann et al. showed that the treatment efficacy was significantly higher with twice daily administration. Negativity for HCV RNA measured by Amplicor assay in the twice-a-day administration group was 18%, 73% and >89% at 1, 2 and 3 weeks, respectively, in contrast to 0%, 0%, and 18%, respectively, with once-a-day administration. However, a significant reduction of platelet count and albumin level, a marked increase in serum aspartate aminotransferase/alanine aminotransferase, and a high incidence of renal toxicity (proteinuria) were found in patients receiving IFN twice a day in comparison with those receiving it once a day.

CONCLUSION

The twice-a-day administration of IFN accelerated the clearance of HCV RNA from serum, leading to a more efficient virological response for patients with chronic hepatitis C, but with a high rate of renal toxicity.

Virus entry is a major determinant of cell tropism of Edmonston and wild-type strains of measles virus as revealed by vesicular stomatitis virus pseudotypes bearing their envelope proteins

The Edmonston strain of measles virus (MV) that utilizes the human CD46 as the cellular receptor produced cytopathic effects (CPE) in all of the primate cell lines examined. In contrast, the wild-type MV strains isolated in a marmoset B-cell line B95a (the KA and Ichinose strains) replicated and produced CPE in some but not all of the primate lymphoid cell lines. To determine the mechanism underlying this difference in cell tropism, we used a recently developed recombinant vesicular stomatitis virus (VSV) containing as a reporter the green fluorescent protein gene in lieu of the VSV G protein gene (VSVDeltaG*). MV glycoproteins were efficiently incorporated into VSVDeltaG*, producing the VSV pseudotypes. VSVDeltaG* complemented with VSV G protein efficiently infected all of the cell lines tested. The VSV pseudotype bearing the Edmonston hemagglutinin (H) and fusion (F) protein (VSVDeltaG*-EdHF) infected all cell lines in which the Edmonston strain caused CPE, including the rodent cell lines to which the human CD46 gene was stably transfected. The pseudotype bearing the wild-type KA H protein and Edmonston F protein (VSVDeltaG*-KAHF) infected all lymphoid cell lines in which the wild-type MV strains caused CPE as efficiently as VSVDeltaG*-EdHF, but it did not infect any of the cell lines resistant to infection with the KA strain. The results indicate that the difference in cell tropism between these MV strains was largely determined by virus entry, in which the H proteins of respective MV strains play a decisive role.

[Basic study on anti-bacterial urethral catheter. II. Potency of a new anti-bacterial catheter and its durability in experimental models]

The potency and effectiveness of an anti-bacterial catheter coated with a mixture of silver citrate, soybean lecithin and liquid silicon at the ratio of 2:2:8 were compared with those of commercially available anti-bacterial and conventional urethral catheters. This new anti-bacterial catheter showed a strong activity and excellent durability in ordinary in vitro experimental studies. In the present series we have developed new in vitro experimental models for the evaluation of anti-bacterial catheters in inhibiting bacterial ascent via intraluminal or extraluminal route. The characteristic features of the silver citrate/lecithin catheter, namely strong activity and excellent durability, were confirmed using these new models that mimic urinary catheter-associated clinical infections.

[Basic study on anti-bacterial urethral catheter. I. Development of a new anti-bacterial coating material for silicon catheters]

In order to develop a new anti-bacterial urethral catheter, we studied anti-bacterial and anti-adherent coating material suitable for silicon catheters. Several aspects of various silver compounds were examined, including anti-bacterial activity, chemical property and toxicity. Among silver citrate, silver phosphate and silver oxide, which were found to have excellent anti-bacterial activities, silver citrate was regarded as the material of choice for anti-bacterial coating in terms of durable activity and biological safety. It was also found that several surfactants inhibited bacterial adherence to the surface of silicon catheters. Among them soybean lecithin exhibited excellent anti-adherent activity in a dose dependent manner. Finally, a mixture of silver citrate, soybean lecithin and liquid silicon at the ratio of 2:2:8 was regarded as an ideal anti-bacterial coating material for silicon catheters.

Avoidance of bone marrow suppression using A-5021 as a nucleoside analog for retrovirus-mediated herpes simplex virus type I thymidine kinase gene therapy

Gene therapy using the herpes simplex virus thymidine kinase (HSV-TK) gene combined with an anti-herpes drug, ganciclovir (GCV), has been applied for human diseases, especially for cancer treatment. However, bone marrow toxicity has been the most consistent adverse effect of GCV treatment in clinical settings. We evaluated the cytotoxic activity of a novel guanosine analog, (1'S,2'R)-9[[1',2'-bis(hydroxymethyl)cycloprop-1'-yl]methyl]guanin e (A-5021), against retrovirus-mediated HSV-TK gene-transduced human lung cancer cells. The bone marrow toxicity of A-5021 and GCV was studied by colony formation assay in both rodent and human bone marrow specimens. We demonstrated that A-5021 had potent cytotoxic activity equal to that of GCV against the retroviral vector-mediated HSV-TK gene-transduced lung cancer cell lines. Further, phosphorylated A-5021 could be transferred to neighboring cells, and this analog killed HSV-TK- neighboring cells, as was the case for GCV. In contrast, A-5021 did not exhibit an inhibitory effect on bone marrow progenitor cells and colony formation (the 50% inhibitory concentration of the colony-forming units in culture = >100 microg/mL in human bone marrow specimens and >66 microg/mL in rodent bone marrow specimens). These results indicate that A-5021 has potent cytotoxic activity as a nucleoside analog for gene therapy using HSV-TK gene, and can be used much more safely than GCV.

[Second reconstructions after failure of free-tissue transfer in the head and neck region]

A retrospective study was performed on 74 patients seen in our hospital between 1990 and 1999 who underwent head and neck reconstructive surgery involving a free flap. Reconstructive surgery was unsuccessful in 5 cases (6.8%). A pedicled myocutaneus flap was used in two cases for the second reconstruction attempt, while a second free flap (jejunum) was used in two other patients. In these cases, a bilateral neck dissection was performed prior to the second free flap reconstruction and neck infection was found. The head and neck artery and vein were unsuitable as recipient vessels in the second operation. Instead, the cephalic vein was used as a source of vein grafts and as a recipient vein.

A simultaneous monitoring of Lens culinaris agglutinin A-reactive alpha-fetoprotein and des-gamma-carboxy prothrombin as an early diagnosis of hepatocellular carcinoma in the follow-up of cirrhotic patients

To elucidate the risk factors for developing hepatocellular carcinoma (HCC) during the follow-up of patients with liver cirrhosis (LC), outpatients with LC were examined periodically by means of serum biochemical assessments, ultrasonography, and computed tomography. Risk factors for HCC were statistically analyzed. We also examined an efficacy of Lens culinaris agglutinin A-reactive profiles of alpha-fetoprotein (AFP-L3%) and des-gamma-carboxy prothrombin (DCP) value using a highly sensitive DCP determination kit (ED036) for the early recognition of HCC. The AFP-L3% and the ED036 value were retrospectively determined with stored serum samples. HCC was diagnosed in 21 of the 78 patients with LC during the follow-up period (mean follow-up period: 42 months). The estimated cumulative incidence of HCC was 25% with 3 years and 48% with 5 years. The most significant risk factor for the development of HCC in LC patients was found to be the mean serum AFP concentration from the year before the HCC detection (p=0.02). At the time of the recognition of HCC, the positive rates of the tumor markers were: serum AFP concentration 14%, serum DCP value 5%, AFP-L3% was 33%, and that of ED036 43%. The positive rate in collaborative use of AFP-L3% and ED036 was 67%. The simultaneous determination of the AFP-L3% and the ED036 value was shown to be effective for the early detection of HCC.

Hepatic heme metabolism in rats with fever induced by interleukin 1beta

We have recently reported that the content of hepatic cytochrome P450 (CYP) apparently decreased in fever model rats, which were created by repeated injection of recombinant human interleukin-1beta (rhIL-1beta) into the cerebroventricle. To make clear the biochemical mechanism of the decreased CYP content, we examined the effect of fever on the activities of hepatic enzymes involved in the biosynthetic and degradative pathways of heme. The activities of delta-aminolevulinic acid synthase, a rate-limiting enzyme in the heme biosynthesis, and porphobilinogen synthase in the liver of rhIL-1beta-induced fevered rat were significantly lower than those in the control, whereas the activity of heme oxygenase, a key enzyme in the heme-degradative pathway, markedly increased in the fevered rat. Moreover, the heme saturation of tryptophan 2,3-dioxygenase in the fevered rat liver was decreased to 43% of the control. These results indicate that fever diminishes the hepatic heme content by decreasing the heme biosynthesis and by accelerating the heme degradation. The deficiency of hepatic heme pool may be one of the main mechanisms that cause the impairment of CYP synthesis.

Synthesis and structure-activity relationships of a new class of selective EP3 receptor agonist, 13,14-didehydro-16-phenoxy analogues of prostaglandin E1

A series of 13,14-didehydro-16-phenoxy analogues of prostaglandin E1 was synthesized and their agonistic activity on EP receptor subtypes was evaluated. 13,14-Didehydro-16-phenoxy-1-decarboxy analogues, 7e and 7f, display highly selective activity on the EP3 receptor subtype, thus, their utility as a selective anti-ulcer agent can be expected.

Development of an experimental apparatus for investigating lymphatic pumping activity of murine mesentery in vivo

The present study has been attempted to establish a modified intravital microscope system for investigating murine lymphatic pumping activity in vivo and evaluate whether or not there is rhythmic pumping activity of murine mesenteric lymphatic vessels in vivo. We designed and constructed a custom organ chamber with a semicircular channel (8 mm in radius, 5 mm in width, 3 mm in depth), being suitable for the superfusing of murine mesentery in vivo. A marked lymphatic pumping activity was observed in the mesenteries of DDY mice. The maximal and minimal diameter and frequency in the pumping activity were 60.9 +/- 1.0 microm, 53.7 +/- 1.8 microm and 12.8 min(-1) (n = 5), respectively. Both NE (norepinephrine, 10(-8)-10(-6) M) and TEA (tetraethylammonium, 1-10 mM) caused dose-dependent constriction of the mesenteric lymphatic vessels in the mice. These findings suggest that a modified intravital microscope system with a specially designed and constructed edge-monitoring device enables us to investigate in vivo lymphatic circulation in murine mesenteries.

Synthesis and antiviral activity of novel anti-VZV 5-substituted uracil nucleosides with a cyclopropane sugar moiety

A series of 5-substituted uracil nucleoside derivatives with a 1(1'S, 2'R)-[1',2'-bis(hydroxymethyl)cyclopropyl]methyl group as an acyclosugar moiety were synthesized and evaluated for their anti-herpetic activities. Among the compounds synthesized, (E)-5-halovinyluracil derivatives showed superior anti-varicella zoster virus (VZV) activity over acyclovir (ACV) but were less potent than ACV against herpes symplex virus type-1 (HSV-1). IC(50) values for the VZV Kawaguchi strain were 0.027 for Br, 0.070 for Cl, and 0.054 microg/mL for I derivatives and 3.4 microg/mL for ACV. The most potent compound, (1'S,2'R)-5-[(E)-2-bromoethenyl]-1-[[1', 2'-bis(hydroxymethyl)cycloprop-1'-yl]methyl]-2,4-(1H, 3H)-pyrimidinedione (3a), was 40-60-fold more potent than ACV against clinical isolates of VZV. It showed good oral bioavailability in rats (68.5%) and, unlike (E)-5-(2-bromovinyl)-1-beta-D-arabinofuranosyluracil (BVaraU), did not result in the release of (E)-5-(2-bromovinyl)uracil (BVU), a potent dihydropyrimidine dehydrogenase inhibitor, in plasma after oral administration.

Surgical management of pulmonary aspergilloma. Role of single-stage cavernostomy with muscle transposition

OBJECTIVE

We reviewed the outcome of the patients with aspergilloma who were treated surgically.

METHODS

Between July 1991 and October 1996, 11 patients with pulmonary aspergilloma underwent surgery. One underwent sequential bilateral tboracotomy and two underwent re-operation. The total number of operations was 14. Surgical procedures consisted of 5 cavernostomies with muscle transposition, 3 cavernostomies with muscle transposition and thoracoplasty, 1 lobectomy 1 pneumonectomy, 1 segmentectomy and 3 partial resections.

RESULTS

Morbidity and mortality rates were 28.6% and 7.1%, respectively Two patients who underwent cavernostomy and muscle transposition experienced a relapse of aspergilloma 19 and 29 months after the operation, respectively, but both successfully underwent re-operation, including cavernostomy. Both are free of symptoms 28 and 30 months after re-operation, respectively. All survivors except for one who died of multiple organ failure remain free of symptoms 14 to 60 months after the most recent operation.

CONCLUSION

Our experience was not a controlled trial and two relapsed cases had undergone cavernostomy, our series may suggest that single-stage cavernostomy with muscle transposition is a viable surgical option for patients with pulmonary aspergilloma.

Roles of three histidine kinase genes in hyphal development and virulence of the pathogenic fungus Candida albicans

The pathogenic fungus Candida albicans harbors three histidine kinase genes called CaSLN1, CaNIK1, and CaHK1. The disruption of any one of these three genes impaired the hyphal formation and attenuated the virulence of C. albicans in a mouse systemic candidiasis model. The effects of the disruption on hyphal formation and virulence were most severe in the cahk1Delta null mutants. Although the double disruption of CaSLN1 and CaNIK1 was impossible, further deletion of CaSLN1 or CaNIK1 in the cahk1Delta null mutants partially restored the serum-induced hypha-forming ability and virulence. When incubated with radiolabelled ATP, the recombinant CaSln1 and CaNik1 proteins, which contained their own kinase and response regulator domains, were autophosphorylated, whereas CaHk1p was not. These results imply that in C. albicans, CaSLN1 and CaNIK1 function upstream of CaHK1 but are in distinct signal transmission pathways.

Various extrahepatic manifestations caused by hepatitis C virus infection

It has been reported that hepatitis C virus (HCV) causes not only liver disease but also disorders of other organs and tissues. Previously, many HCV-related extrahepatic manifestations have been reported. In this study, we report 2 patients in whom tongue cancer was detected during the treatment of HCV-related liver disease. In one patient, tongue cancer was detected during the treatment of HCV-related liver cirrhosis, and articular rheumatism developed thereafter. The duration of HCV-related liver disease was 10 years. In the other patient, tongue cancer was detected during the treatment of HCV-related hepatocellular carcinoma. This patient had a past history of thyroid disease. The duration of HCV-related liver disease was 6 years. In these patients, the possibility that several conditions incidentally and concurrently developed cannot be denied. However, the conditions described above may be regarded as HCV-related extra-hepatic manifestations. In patients with HCV infection, it is important to examine conditions in organs other than the liver. Careful follow-up is needed.

Budd-Chiari syndrome complicated by hepatocellular carcinoma with no evidence of infection with hepatitis virus: a case report

Hepatocellular carcinoma occurs in patients with Budd-Chiari syndrome. However, the etiology of hepatocellular carcinoma accompanied with Budd-Chiari syndrome has not been elucidated. We report a case of Budd-Chiari syndrome with membranous obstruction of the inferior vena cava complicated by hepatocellular carcinoma in an 80 year-old man. There was no evidence of co-infection with hepatitis A, B, C, D, E, and G virus. Histologically, the non-cancerous liver tissue showed chronic venous congestion with no evidence of hepatitis virus-associated liver cirrhosis. This case suggests that chronic venous congestion of the liver may be one of the pathologic conditions that occurs in hepatocellular carcinoma.

Amino acid substitutions at position 481 differently affect the ability of the measles virus hemagglutinin to induce cell fusion in monkey and marmoset cells co-expressing the fusion protein

The hemagglutinin (H) protein of the measles virus (MV) Edmonston strain induced cell fusion in Cos (monkey) and B95a (marmoset) cells, when co-expressed with the fusion (F) protein, whereas the H protein of the wild-type KA strain induced fusion in B95a cells, but not in Cos cells. Asparagine residue at position 481 of the KA H protein was replaced by various amino acids through site-directed mutagenesis. Substitution with tyrosine, which was found at position 481 of the Edmonston H protein, enabled the mutant KA H protein (N481Y) to induce cell fusion in Cos cells co-expressing the F protein, which could be completely blocked by anti-CD46 antibody. This mutant, however, did not cause CD46 downregulation, unlike the Edmonston H protein. The other H protein mutants (N481S, N481T, N481D, N481H, N481F) did not produce syncytia in Cos cells. On the other hand, all of the mutants retained the ability to induce cell fusion in B95a cells. Thus, while tyrosine at position 481 was indispensable for the MV H protein's interaction with CD46, the residue at this position does not appear to be critically involved in the interaction with the receptor for wild-type strains present on B95a cells.

Involvement of ATP-sensitive K(+) channels in spontaneous activity of isolated lymph microvessels in rats

Physiological roles of ATP-sensitive K(+) channels for spontaneous activity in isolated rat mesenteric lymph microvessels (maximum diameter approximately 80-150 microm) were investigated. The lymph microvessels were cannulated with glass micropipettes and pressurized at a perfusion pressure of 6 cmH(2)O. Changes in the diameter and frequency of spontaneous contractions in the lymphatics were measured with videomicroscopy. Pinacidil (K(+)-channel opener) inhibited the spontaneous activity. In the presence of glibenclamide (selective ATP-sensitive K(+)-channel blocker; 10(-7) and 10(-6) M) and tetraethylammonium (TEA; nonselective K(+)-channel blocker; 10(-4) and 10(-3) M), the pinacidil-induced inhibition of the spontaneous contractions in lymph microvessels was significantly reversed. Glibenclamide and TEA themselves, however, did not affect the frequency of spontaneous activity in the lymph microvessels. These results suggest that ATP-sensitive K(+) channels are involved in the regulation of spontaneous activity in the smooth muscles of isolated lymph microvessels of rat mesenteries.

cDNA cloning and chromosomal mapping of rat Smad2 and Smad4 and their expression in cultured rat articular chondrocytes

Smad proteins are known to transduce signalling of TGF-beta receptor superfamily. We report here the entire sequences of rat Smad2 and Smad4 which have not been identified yet. Entire sequences were identified by degenerated polymerase chain reaction and following phage library screening and 5' RACE. The predicted amino acid sequences of rat Smad2 and Smad4 are highly conserved among rat, human and mouse. We also mapped these Smads to chromosome 18q.12.3. Unlike endothelial cells, TGF-beta1 stimulates articular chondrocyte proliferation as well as extracellular matrix production, and acts as a repairing agent against cartilage destruction. Since both Smad2 and Smad4 are essential factors for TGF-beta signalling, we examined their expression and regulation in cultured articular chondrocytes. Northern blot analysis showed that TGF-beta1 significantly increased the mRNA level of Smad2 but not of Smad4 in a dose- and time-dependent manner, suggesting that the augmentation of TGF-beta1 action is caused by increasing the expression of the downstream signalling molecule.