Assembly of JC virus-like particles in COS7 cells

JC virus lacks an appropriate cell line to support virus replication. The establishment of a JC pseudovirus assembly system could play an alternative role for a virus culture system. COS7 cells and a transfer vector, pcDL-SR alpha 296, were used to express JC viral structural genes. VP231-SR alpha, which encodes VP2/VP3 and VP1, but lacks 137 bp of the 5'-terminus of agnogene, showed both efficient nuclear migration and quantitative expression of the major capsid protein VP1. JC pseudovirus assembly was observed in the nucleus of VP231-SR alpha transfected cells. Evidence of JC pseudovirus assembly is presented. The further utilization of this system, which includes a study for the viral morphogenesis, serological diagnosis, as well as the potential application for gene transfer vector, is discussed.

[Progressive multifocal leukoencephalopathy]

Progressive multifocal leukoencephalopathy (PML) is the only polyomavirus infection in human caused by JC virus. Clinically PML is diagnosed by neurological signs, supported by MRI and PET, but its pathologic diagnosis at brain biopsy remains to be a confirmative method, although the PCR method, using csf, gives a predictive value. Virological study of the regulatory region of viral genome has suggested that PML-inducing viral type may be derived from the urine-excreted virus (archetype) by mechanisms involving nucleotide deletion and duplication. Viral neurotropism has been shown to be closely related to transcriptional function of the viral promoter-enhancer which cellular proteins bind to and is activate by. Of these, NF-1 binding proteins, glial factor-1, Tst-1 (SCIP, Oct-6) and others should be tested for their specificity to human glial cell.

A rat model of Parkinson's disease induced by Japanese encephalitis virus

In Fischer rats infected with Japanese encephalitis virus (JEV) at 13 days after birth and sacrificed 12 weeks later, the major pathological changes resembled those found in Parkinson's disease. Specifically there was neuronal loss with gliosis which was confined mainly to the zona compacta of the substantia nigra, with a notable absence of lesions in the cerebral cortex and cerebellum. Changes were bilateral being most severe in the central part of the zona compacta. Immunohistochemical studies with anti-tyrosine hydroxylase (TH) demonstrated that the number of TH-positive neurons was significantly decreased in the substantia nigra compared to controls, while comparable numbers of TH-positive neurons were found in the basal ganglia in both JEV-treated rats and age-matched controls. JEV-infected rats showed marked bradykinesia, with significant behavioral improvement being observed following administration of L-DOPA. Immunohistochemical studies failed to detect JEV antigens in any region of the rat brain and the JEV genome was undetectable in the substantia nigra and the cerebral cortex using the reverse transcription-polymerase chain reaction (RT-PCR). The findings suggest that JEV infection of rats under the conditions described may serve as a model of virus induced Parkinson's Disease.

The role of topoisomerase I in HIV-1 replication

The mechanisms involved in the restriction of the cellular tropism of HIV-1 to cells of primate origin remain to be clearly defined. However, a number of studies have shown that this is determined not only at the level of the cellular receptor(s) or virus entry, but at a number of additional and later stages in virus replication. We have recently reported that the reverse transcription of HIV-1 RNA is markedly enhanced by the association of the gag encoded nucleocapsid p15 protein and cellular topoisomerase 1. In the present study we have now investigated if the recruitment of cellular topoisomerase I during virus replication is important in determining the cellular tropism of HIV-1. Employing a stable murine cell line, L929, expressing both human CD4 and topoisomerase I, it could be demonstrated that effective proviral DNA synthesis occurred following infection. In contrast in cells expressing only human CD4 proviral DNA synthesis was not detected. In addition we have co-expressed fusin, a protein known to act as an accessory factor as the virus entry stage in infection of T cell tropic HIV-1, to support viral entry completely. However no progeny virus could be detected after HIV-1 infection. These results suggest that reverse transcription in vivo is critically dependent on the presence of cellular topoisomerase I, and support the view that involvement of this enzyme is in HIV-1 replication. Moreover the findings suggest that other factors which remained to be identified, are involved in restricting HIV-1 replication in non-primate cells.

Michelin tire syndrome: a congenital disorder of elastic fibre formation?

We describe a 15-month-old girl with Michelin tyre syndrome. She had hirsuties and marked skin folds. Histological examination showed fragmented elastic fibres in addition to smooth muscle hamartoma. On electron microscopy, decreased deposition of elastin was observed. We speculate that elastic fibre abnormalities may account for the characteristic skin changes in the Michelin tyre syndrome.

The role of topoisomerase I in HIV-1 replication

The mechanisms involved in the restriction of the cellular tropism of HIV-1 to cells of primate origin remain to be clearly defined. However, a number of studies have shown that this is determined not only at the level of the cellular receptor(s) or virus entry, but at a number of additional and later stages in virus replication. We have recently reported that the reverse transcription of HIV-1 RNA is markedly enhanced by the association of the gag encoded nucleocapsid p15 protein and cellular topoisomerase I. In the present study we have investigated if the recruitment of cellular topoisomerase I during virus replication is important in determining the cellular tropism of HIV-1. Employing a stable murine cell line, L929, expressing both human CD4 and topoisomerase I, it could be demonstrated that effective proviral DNA synthesis occurred following infection. In contrast in cells expressing only human CD4, proviral DNA synthesis was not detected. In addition we have co-expressed fusin, a protein known to act as an accessory factor as the virus entry stage in infection of T cell tropic HIV-1, to support viral entry completely. However no progeny virus could be detected after HIV-1 infection. These results suggest that reverse transcription in vivo is critically dependent on the presence of cellular topoisomerase I, and support the view that involvement of this enzyme is important in HIV-1 replication. Moreover the findings suggest that other factors which remained to be identified, are involved in restricting HIV-1 replication in non-primate cells.

Phosphatidylserine externalization is a downstream event of interleukin-1 beta-converting enzyme family protease activation during apoptosis

Phosphatidylserine (PS), a class of acidic phospholipids, normally localizes on the internal surface of cellular plasma membranes. The internal PS is externalized when cells undergo apoptosis; however, the mechanism for this is largely unknown. To study the mechanism of PS externalization during development of apoptosis, we examined the correlation between the activation of interleukin-1 beta-converting enzyme (ICE) family protease and PS externalization in human monocytic leukemia U937 cells and in their apoptosis-resistant variants, UK711 and UK110, after treatment with etoposide and anti-Fas antibody. We found that PS externalization accompanied the development of apoptosis and the activation of ICE family proteases in these cell lines. Furthermore, inhibitors of ICE family proteases, Z-Asp and Z-VAD, prevented apoptosis and PS externalization in etoposide-treated U937 cells. These results indicate that PS externalization is a downstream event of ICE family protease activation during apoptosis development. Because ICE family proteases play a crucial role in apoptosis, PS externalization could be a rational and useful marker for the development of apoptosis.

Negative pressure breathing and the control of skin blood flow during exercise in a hot environment

Factors which modify the relationship between body temperature and skin blood flow during exercise in heat were studied. Direct measurement of right atrial pressure during exercise in heat showed that the leveling off of forearm blood flow took place when blood temperature exceeded 38 degrees C and central venous pressure was lower than 6.3 mm Hg. Continuous negative pressure breathing increased the forearm and chest blood flow and the esophageal temperature at which leveling off was observed shifted from 37.7 degrees C to 38.0 degrees C. When the leveling off temperature was compared between subjects with high and low blood volume, the subject with low blood volume showed the leveling off of forearm blood flow at a temperature of 37.6 degrees C, while it was 38.0 degrees C in the subject with high blood volume. All these results suggest the involvement of cardiopulmonary mechanoreceptors, while further studies are required to clarify the mechanism which the leveling off of skin blood flow is observed at 38 degrees C of body temperature.

Antiproliferative activity in vitro and in vivo of the spicamycin analogue KRN5500 with altered glycoprotein expression in vitro

The spicamycin analogue KRN5500 (NSC 650426; SPA) is derived from Streptomyces alanosinicus. The unique structure contains a purine, an aminoheptose sugar, glycine, and a tetradecadiene fatty acid. SPA potently inhibits the growth of certain human tumor cell lines in vitro (IC50 for growth <100 nM) and displays marked activity in vivo in Colo 205 colon carcinoma xenografts. Selective inhibition of labeled precursor incorporation was not evident at 1 or 4 h of exposure to the drug, but at 8 h, [3H] leucine incorporation was inhibited by approximately 40% at or below the IC50 for cell growth. Because of the structural similarity of SPA to inhibitors of glycoprotein processing, we examined the effect of SPA on indicators of glycoprotein synthesis and processing in HL60TB promyelocytic leukemia and Colo 205 colon carcinoma cells. Brief periods of exposure ( approximately 30 min) to SPA at the IC50 for growth increased incorporation of [3H]mannose. When examined by Western blotting after prolonged (40-48 h) incubation with lectins that target mannose-containing carbohydrates, Galanthus nivalis agglutinin and concanavalin A, a qualitative change in the pattern of mannose-containing glycoproteins was observed in HL60TB cells. Significant changes in the pattern of surface glycoprotein expression in intact cells were demonstrated by flow cytometry using fluorescence-labeled lectins. An increase in the number of cells binding G. nivalis agglutinin (indicating terminal mannose) was noted, but a decrease in the amount of lectin bound per cell was noted for wheat germ agglutinin (detecting sialic acid and terminal beta-N-acetyl glucosamine residues). Electron microscopy revealed loss of microvilli, and the Golgi apparatus appeared inflated. Our findings, therefore, raise the possibility that cells exposed to SPA have altered glycoprotein processing after exposure to low concentrations of drug, prior to the occurrence of overt cytotoxicity. These effects are consistent with a prominent early effect of SPA on the enzymatic machinery or organelles important for proper glycoprotein processing and emphasize the novelty of this agent's likely mechanism of action.

Detection of latent varicella-zoster virus infection in human vestibular and spiral ganglia

Varicella-zoster virus (VZV) becomes latent in the sensory ganglia after primary infection and VZV DNA has been found in human trigeminal, thoracic, and geniculate ganglia. In this study, human vestibular and spiral ganglia, which do not received innervation from the skin, were examined for VZV DNA using the polymerase chain reaction. VZV DNA was detected in 2 of 10 (20%) vestibular ganglia and in 2 of 10 (20%) spiral ganglia from five adults. VZV DNA was undetectable in either type of ganglion from a newborn and from two of the five adults. These two adults were VZV seronegative. The results indicate that VZV becomes latent in several types of sensory ganglion after primary infection and suggest the possibility that reactivation of the virus from the vestibular and spiral ganglia may cause disorders in the labyrinth.

Clinical significance of serum c-erbB-2 protein in patients with primary breast cancer

We measured serum c-erbB-2 protein concentration in 167 patients with primary breast cancer. The rate of positive results was 6%. The positivity rate of serum c-erbB-2 protein did not differ among stages I, II, IIIa and IIIb. However the positivity rate on stage IV was 50% (3/6) and significantly higher than the other stages (p=0.0006). The rate of;positive results correlated significantly with lymph node status (p=0.0037). We concluded that the level of serum c-erbB-2 protein reflected the malignant characteristics of primary breast cancer and its measurement may be useful for a preoperative evaluation of primary breast cancer.

Propagation of the human polyomavirus, JCV, in human neuroblastoma cell lines

Susceptibility to infection by the human polyomavirus, JCV, is determined by intracellular mechanisms which control transcription and replication. Originally thought to propagate well only in human cells of oligodendroglial lineage, JCV has recently been shown to infect astrocytes, astrogliomas, and a neuroblastoma cell line. The data reported here describe two cell types that have been subcultured from a human neuroblastoma cell line, SK-N-SH. The SH-SY5Y subclone displays neuronal phenotypes and is not susceptible to JCV infection, while the SH-EP subclone displays glial cell phenotypes and is susceptible to infection. Binding of nuclear proteins from the permissive SH-EP cells to the nuclear factor-1 (NF-1) site in the JCV regulatory DNA sequences results in a gel shift pattern that is different from the nonpermissive SH-SY5Y cell proteins. Northern analysis of mRNA for the four classes of NF-1 proteins showed a predominance of the NF-1/X class in SH-EP cells similar to the highly permissive human fetal glial cells. Very low levels of mRNA for NF-1/X were seen in the nonpermissive SH-SY5Y cells, similar to that seen for the nonpermissive HeLa cells. Several other cell lines tested that were permissive for JCV infection also showed synthesis of the NF-1/X class of proteins. SH-EP cells represent a cell line in a glial cell lineage which is susceptible to JCV multiplication. These cells may be a useful cell culture system for the investigation of DNA binding factors which correlates with viral susceptibility.

Protein composition and morphology of human foamy virus intracellular cores and extracellular particles

Characterization of human foamy virus (HFV) gag-encoded precursors and the search for a Gag-Pol polyprotein and mature proteins derived from proteolytic processing were carried out in HFV-infected cells and with purified preassembled cores and extracellular virus by Western blotting and radioimmunoprecipitation using antisera against synthetic peptides corresponding to putative Gag and protease proteins. Precursor proteins, Pr78gag/74gag and Pr135pol, were found in the nucleus of epithelial and fibroblast cells 3-4 days after HFV infection. Kinetic analysis of HFV Pr78gag and Pr74gag indicated that Pr78gag is a precursor to Pr74gag. South-Western blot analysis indicated that Pr78gag and Pr74gag have properties associated with nucleic acid binding protein although they lack the typical zinc-finger motifs found in retroviral nucleocapsid proteins. Western blot analyses of preassembled HFV cores isolated from the cytoplasm of infected cells and purified by sucrose gradient centrifugation demonstrated the presence of Pr78gag/74gag and Pr135pol, but no proteolytically processed Gag proteins were observed. The majority of extracellular HFV particles were found to have pentagon-shaped cores, as observed intracellularly, and are believed to be the immature extracellular form of the virus. The highest concentration of extracellular particles, estimated by EM, Western blot, and reverse transcriptase assays were found in sucrose gradient fractions having a density of 1.21-1.24 g/cm3. Western blot analysis revealed that Pr78gag/74gag and Pr135pol were the major viral proteins associated with these extracellular particles, as only small amounts of putative proteolytically cleaved capsid (p32) were observed. Our results support the notion that Pol is translated independent of Gag in HFV-infected cells.

Multiple hilar cysts of the liver in patients with alcoholic cirrhosis: report of three cases

The present report concerns the clinicopathological study of three patients with alcoholic cirrhosis (a 40-year-old man, a 52-year-old woman and a 48-year-old man) who had multiple cysts along their intrahepatic bile ducts. The cysts were visible on gross examination of the liver and, in two cases, an enlargement of the cysts had been detected in abdominal computed tomography scans performed 1 year apart. Histologically, the cysts consisted of proliferating and dilated peribiliary glands. The cysts occasionally compressed the original bile ducts. The latter showed mucosal hyperplasia with antral-type gland metaplasia. Neoplastic changes and necroinflammation were not seen. Immunohistochemical assays revealed that the peribiliary glands and antral-type glands expressed not only cytokeratin and carbohydrate antigen 19-9, but also c-MET protein, the hepatocyte growth factor receptor which may be related, at least in part, to the cystic dilatation of the peribiliary glands.

Lack of evidence for the transmission of JC polyomavirus between human populations

Human polyomavirus JC virus (JCV), the causative agent of progressive multifocal leukoencephalopathy, is ubiquitous in humans, infecting children asymptomatically then persisting in renal tissue. Since JCV DNA can readily be detected from urine, it should be a useful tool with which to study the mode of virus transmission in humans. Based on this notion, we examined the extent to which JCV was transmitted from the American to Japanese populations in Okinawa Island, Japan. (A population of about 50 000 American soldiers and families have been stationed in Okinawa since 1945.) Four JCV types (A to D) were identified in American populations in U.S.A., whereas only type B was prevalent in elder Japanese in Okinawa who had reached adulthood by 1945. Thus, types A, C, and D served as indicators of the transmission of JCV from American to Japanese populations. We then examined whether types A, C, and D were detectable in Japanese in Okinawa aged 30-50 years who may have been in contact with Americans during childhood. However, all the 125 isolates from the younger Japanese population were type B without exception. From this finding, we concluded that JCV is rarely transmitted between human populations.

[Mechanism of neuronal damage in AIDS]

Neurologic problems in AIDS are usually caused by opportunistic infections or secondary malignancy of the central nervous system (CNS), but brain damage occurs primarily as the result of HIV infection in CNS. In one of the typical opportunistic virus infections of CNS, progressive multifocal leukoencephalopathy (PML), oligodendroglial cells which maintain and support myelin sheaths are specifically attacked by JC virus. As the consequence, demyelination occurred, which could well explain the neuronal deficits. In contrast, in HIV the viral target cells are not neuronal cells, but infiltrating macrophages in CNS. Thus, the indirect injury such as HIV-related neurotoxic substances and macrophage-released cytokines would be augmented to induce diffuse neuronal damage in HIV infected brains. Recent discovery of co-receptor, chemokine receptor (CCR5) which is expressed in macrophages, may give a clue to understand the mechanism of HIV encephalopathy more precisely.

Clival chordoma presenting as acute esotropia due to bilateral abducens palsy

A case involving a 14-year-old girl having clival chordoma with symptoms of diplopia, acute esotropia, and bilateral abducens palsy is reported. Magnetic resonance imaging revealed a clival tumor invading the posterior edges of the bilateral cavernous sinuses. After removal of the tumor, no ocular manifestations were noted. The importance of acute esotropia as a sign indicating a possible brainstem mass is emphasized.

Childhood bronchial mucoepidermoid tumors

A very rare case of a childhood bronchial mucoepidermoid tumor is presented. A 4-year-old girl was hospitalized with prolonged pneumonia. Computed tomography of the chest showed a tumor with calcifications in the right upper lobe. Subsequently, the patient underwent right upper lobectomy. Histologically, the tumor was a low-grade mucoepidermoid tumor originating from the bronchus. Three years postoperatively there has been no evidence of disease. A review of the literature indicates that 30 cases of bronchial mucoepidermoid tumors in children have been reported. Symptoms result from associated bronchial obstruction. Children with recurrent or prolonged pneumonia should undergo aggressive diagnostic investigation by chest tomography or bronchoscopy. Appropriate therapy for childhood bronchial mucoepidermoid tumor is total resection of the lesion while sacrificing as little of the normal lung tissue as possible.

Clinicopathological study of choroid plexus tumors: immunohistochemical features and evaluation of proliferative potential by PCNA and Ki-67 immunostaining

This report concerns the retrospective immunohistochemical characterization and evaluation of the proliferative potential of eight choroid plexus tumors (CPTs) that included six cases of choroid plexus papilloma (CPP), one of whom had a recurrence, and two cases of choroid plexus carcinoma (CPC). Antibodies to prealbumin, glial fibrillary acidic protein (GFAP), vimentin, keratin, and carcinoembryonic antigen (CEA) were used to determine the immunohistochemical features of interest. The proliferative potential was evaluated with antibodies to proliferating cell nuclear antigen (PCNA) and Ki-67. Antibody binding was visualized by the avidin-biotin-peroxidase complex (ABC) method. Immunoreactivity was scored on a-to 4+ scale, and in the case of PCNA and Ki-67, expected as staining index (SI). All seven CPP specimens were immunostained for prealbumin, but not for CEA. Expression of GFAP, vimentin and keratin varied from one CPP case to another. Both CPCs expressed CEA, but not prealbumin, GFAP and keratin; one of them was vimentin-positive. As determined by immunostaining for Ki-67, the proliferative potential was lower in the CPPs than in the CPCs. Among the former, the highest Ki-67 SI was seen in the primary lesion of a recurring papilloma. On the other hand, immunostaining for PCNA gave less consistent SI values. Our results show that immunohistochemical assays for prealbumin and CEA expression are of significant value for the differential diagnosis of CPPs and CPCs, and that high Ki-67 SI values may serve as an indicator of CPP recurrence, even if the primary lesion is benign.

[A patient with Sjögren syndrome with central pontine myelinolysis and hypokalemic myopathy]

We report a 42-year-old woman who presented with intermittent episodes of muscular weakness lasting approximate 7 to 10 days, about once a year, since 1985. During these episodes of weakness, hypokalemia and elevation of serum creatine kinase were noted. On admission, xerostomia, keratoconjunctivitis sicca (positive Schirmer test), abnormal sialographic findings (apple tree-like appearance), and positive serum autoantibodies against ss-A and nucleus were noted. These findings were compatible with Sjögren syndrome. She also had hyperchloremic metabolic acidosis with normal anion gap, hypokalemia and renal calcifications. Therefore, she had renal tubular acidosis (type 1) in addition to Sjögren syndrome. Brain magnetic resonance imaging (MRI) demonstrated a symmetrical circumscribed lesion in the ventral part of the central pons. We considered this lesion to be central pontine myelinolysis (CPM), because of its typical location and characteristic MRI appearance. This CPM was clinically silent. Pathogenesis and etiology of CPM are obscure, and CPM associated with hypokalemia without hyponatremia has rarely been reported in the literature. However, this is the first report of CPM associated with Sjögren syndrome and hypokalemic myopathy complicated with renal tubular acidosis.