Sequence analysis and molecular characterization of genes required for the biosynthesis of type 1 capsular polysaccharide in Staphylococcus aureus

We previously cloned a 19.4-kb DNA region containing a cluster of genes affecting type 1 capsule production from Staphylococcus aureus M. Subcloning experiments showed that these capsule (cap) genes are localized in a 14.6-kb region. Sequencing analysis of the 14.6-kb fragment revealed 13 open reading frames (ORFs). Using complementation tests, we have mapped a collection of Cap- mutations in 10 of the 13 ORFs, indicating that these 10 genes are involved in capsule biosynthesis. The requirement for the remaining three ORFs in the synthesis of the capsule was demonstrated by constructing site-specific mutations corresponding to each of the three ORFs. Using an Escherichia coli S30 in vitro transcription-translation system, we clearly identified 7 of the 13 proteins predicted from the ORFs. Homology search between the predicted proteins and those in the data bank showed very high homology (52.3% identity) between capL and vipA, moderate homology (29% identity) between capI and vipB, and limited homology (21.8% identity) between capM and vipC. The vipA, vipB, and vipC genes have been shown to be involved in the biosynthesis of Salmonella typhi Vi antigen, a homopolymer polysaccharide consisting of N-acetylgalactosamino uronic acid, which is also one of the components of the staphylococcal type 1 capsule. The homology between these sets of genes therefore suggests that capL, capI, and capM may be involved in the biosynthesis of amino sugar, N-acetylgalactosamino uronic acid. In addition, the search showed that CapG aligned well with the consensus sequence of a family of acetyltransferases from various prokaryotic organisms, suggesting that CapG may be an acetyltransferase. Using the isogenic Cap- and Cap+ strains constructed in this study, we have confirmed that type 1 capsule is an important virulence factor in a mouse lethality test.

A catalogue of genes in the cardiovascular system as identified by expressed sequence tags

The heart, which is composed of all the cellular components of the circulatory system, is a representative organ for obtaining genes expressed in the cardiovascular system in normal and disease states. We used partial sequences of cDNA clones, or expressed sequence tags, to identify and tag genes expressed in this organ. More than 3500 partial sequences representing > 3000 cDNA clones have been obtained from either the 5' or 3' end of inserts derived from human heart cDNA libraries. Of 3132 cDNA clones analyzed by sequence similarity searching against the GenBank/EMBL data bases, 1485 (47.4%) were found to represent additional, previously undiscovered genes, whereas 267 clones were matched to human brain expressed sequence tags. Clones matching to known genes were catalogued according to their putative structural and cellular functions. cDNA probes from reverse-transcribed mRNAs of fetal and adult hearts were used to study differential expression of selected clones in cardiac development. Cataloguing genes expressed in the heart may provide insight into the genes involved in health and cardiovascular disease.

Pyogenic liver abscess in beta-thalassemia major--report of two cases

Pyogenic liver abscess, which may lead to devastating consequences, is an uncommon medical problem in pediatrics and has generally been reported in compromised hosts. This article describes two patients with beta-thalassemia major and hemochromatosis complicated by Klebsiella pneumoniae liver abscess. One of the patients had severe complications, including subphrenic abscess, pleural effusion and meningitis. To present knowledge, the occurrence of K. pneumoniae liver abscess in patients with beta-thalassemia major has never before been reported in the literature.

Cellular distribution of pulmonary Mn and CuZn superoxide dismutase: effect of hyperoxia and interleukin-1

Pulmonary superoxide dismutase (SOD) plays an important role in the lung defense against O2 toxicity. We have previously demonstrated that tracheal insufflation of interleukin-1 alpha (IL-1) selectively enhances pulmonary MnSOD and protects rats against O2 toxicity. However, little is known about the cellular distribution of pulmonary MnSOD- and CuZnSOD-specific proteins. We performed immunohistochemistry in plastic sections (2 microns thick) to determine the effects of hyperoxia and IL-1 on the cellular distribution of pulmonary MnSOD and CuZnSOD in rats. MnSOD and CuZnSOD were present in all lung cells. Smooth muscle and endothelial cells appeared to contain higher immunoreactive MnSOD and CuZnSOD proteins than other lung cell types. Exposure of rats to 100% O2 for 24 hr had no effect on the cellular distribution and intensity of pulmonary MnSOD. However, at 50 hr after O2 exposure the intensity of pulmonary MnSOD was reduced. In contrast, tracheal insufflation of IL-1 markedly enhanced the intensity of pulmonary MnSOD in rats exposed to O2 for 50 hr. Neither O2 exposure nor IL-1 insufflation had any apparent effect on the distribution and intensity of pulmonary CuZnSOD. We conclude that IL-1 selectively enhances pulmonary MnSOD and that this effect is manifested in most lung cells, particularly smooth muscle and endothelial cells.

Long term clinical and virologic outcome of primary hepatitis C virus infection in children: a prospective study

To investigate the long term natural course of primary hepatitis C virus infection in children from the beginning, we prospectively followed up 88 children at risk because of frequent blood transfusions or of hepatitis C virus infection from the mother. Ten of the 88 children contracted primary infection during follow-up. In the acute stage of infection acute hepatitis with elevation of aminotransferases and a positive IgM antibody was found in both children infected during open heart surgery, 3 of the 5 multiply transfused children with congenital hemolytic anemia and none of the 3 infants infected by their mothers. Four of the 10 children later lost hepatitis C virus RNA, whereas 6 had a chronic course. Three of the latter 6 children had abnormal aminotransferase activities in the chronic phase. Our study suggests that the very young age of primary infection and the underlying status of the host may affect the clinical course of hepatitis C virus infection in children.

Anti-human sperm monoclonal antibody HS-11: a potential marker to detect bovine sperm capacitation and acrosome reaction in vitro

The crossreactivity between bull spermatozoa and monoclonal antibodies initially raised against mouse spermatozoa and human spermatozoa was tested by indirect immunofluorescent assay. The three anti-human spermatozoa monoclonal antibodies examined (HSK-9, HS-11, HS-63) crossreacted with methanol-fixed bull spermatozoa, whereas the anti-mouse spermatozoa monoclonal antibodies (MS-4 and MS-7) did not. A separate experiment was conducted to determine the binding ability of HSK-9, HS-11 and HS-63 with live (fresh) bull spermatozoa incubated (39 degrees C in CO2 incubator) in a capacitation medium (modified Tyrode's supplemented with 10 micrograms heparin ml-1). The binding of the monoclonal antibodies to the intra-acrosomal antigens of live bull spermatozoa was determined at 0, 2, 4, 6 and 8 h of incubation. At the beginning of incubation, binding was minimal (3.2 +/- 1.7%), but a much higher percentage of spermatozoa exhibited fluorescent staining after 2 h. The maximal binding was observed after incubation for 8 h (72.0 +/- 8.2%). The third experiment was performed to determine binding of HS-11 to frozen-thawed spermatozoa and to test whether there was any variation among bulls in HS-11 binding to spermatozoa, and to assess whether such binding is an indication of sperm capacitation. Frozen-thawed semen samples from five bulls were assessed for antibody binding after 0, 2, 4 and 6 h of incubation. Maximal binding was observed at 4 h. Lysophosphatidylcholine (100 micrograms ml-1) induced acrosome reaction assay was performed to assess sperm capacitation at various intervals.(ABSTRACT TRUNCATED AT 250 WORDS)

Response to supplementary vaccination with recombinant or plasma hepatitis B vaccine in healthy non-responding children

Fifty-three children who failed to respond to four doses of plasma hepatitis B (HB) vaccine (anti-HBs titre < 10 IU l-1) were divided into two groups and received revaccination with either three doses of recombinant HB vaccine (10 micrograms/dose, by 0, 1, 6 month schedule; group A) or two additional doses of plasma HB vaccine (5 micrograms/dose, by 0, 1 month schedule; group B) respectively. Thirty-two vaccinees in group A had a response rate (with anti-HBs > 10 IU l-1) of 53.1% (17/32), 87.5% (28/32), and 100% (32/32) after first, second and third doses of the vaccine respectively. Twenty-one vaccinees in group B had a response rate of 61.9% (13/21) after two additional doses of plasma vaccine. High anti-HBs titres (> 1000 IU l-1) were noted in 50% of the vaccinees in group A after three doses of vaccine. Comparing anti-HBs response between group A and group B after two additional doses of HB vaccine, group A had a higher anti-HBs titre (geometric mean titre 104.7 IU l-1 versus 75.9 IU l-1) along with a better seroconversion rate (87.5 versus 61.9%). However, the differences in vaccine dose between the two groups may also be a contributory factor. Our findings indicate that three doses of recombinant HB vaccine were invariably effective in eliciting a good immune response in previous non-responders to the four doses of plasma HB vaccine. Therefore, it is speculated that these young vaccinees who did not respond to four doses of plasma HB vaccine may not be real non-responders, but hyporesponders.

Productive infection of human endometrial stromal cells by human cytomegalovirus

Cultured endometrial stromal cells were susceptible to productive human cytomegalovirus (HCMV) infection. Infection of endometrial stromal cells resulted in pronounced cytopathic effects including cell rounding and aggregation, fusions, and some lysis, although not in the synchronous fashion observed in infected fibroblasts. The aggregation events were reminiscent of normal endometrial stromal cell responses to cyclical estrogen/progesterone levels. Immunofluorescence analysis demonstrated expression of viral gene products suggesting a productive virus infection. One-step growth analysis showed that infectious virus was produced but the titers were two logs lower than those obtained in fibroblasts even though HCMV DNA accumulated to similar levels in both cell types. In contrast, viral DNA replication was greatly reduced in endometrial stromal cells immortalized with a temperature-sensitive SV40 large T gene at both permissive and nonpermissive temperatures. A more detailed analysis of viral gene expression by Northern blotting revealed earlier appearances and greater initial levels of viral transcripts in endometrial stromal cells. No HCMV gene expression was observed at 120 hpi in these cells even though half of the cells were still intact and cellular gene expression was functional. Since this was the time of peak virus production, it seems plausible that reduced viral gene expression at late times p.i. was a major contributor to the reduced titers observed in endometrial stromal cells. These in vitro results coupled with in vivo observations by others of endometritis associated with HCMV suggest that further investigation into the effects of HCMV on the endometrium is warranted.

Kimura's disease--report of four cases

Kimura's disease is a rare benign condition that occurs predominantly in Oriental young people. The patients displayed a variety of manifestations such as painless, tumor-like masses in the head and neck regions, or in the salivary glands with associated lymphadenopathy. They are sometimes initially mistaken for malignant tumors, resulting in improper management. We present four cases of Kimura's disease and a comprehensive review of the literature to increase awareness and alert surgeons and pathologists to consider the possibilities of this disease, especially in Oriental patients having peripheral blood eosinophilia and/or elevated serum IgE.

Cytomegalovirus-induced persistent mononucleosis in an infant

Chronic mononucleosis has recently gained much attention in the literature. Almost all cases of this new syndrome have been ascribed to persistent Epstein-Barr virus infection. However, a case presented with infantile chronic mononucleosis syndrome caused by persistent cytomegalovirus infection. Transient clonal chromosomal change was noted during follow-up.

Freezing of mammalian livers with glycerol and antifreeze proteins

We have tested a protocol that uses a new cryoprotective solution for preserving mammalian livers in a frozen state. This protocol is based upon our studies on the mechanisms that freeze tolerant animals use to survive freezing in nature. The cryoprotective solution contains glycerol and antifreeze proteins, both of which are found in freeze tolerant animals. Whole rat livers were frozen to -3 degrees C, maintained at that temperature for 6 hours and then warmed to 37 degrees C. Post thawing bile production and microscopic analysis of tissue slices were used to verify liver function and tissue morphology. We conclude that antifreeze proteins used in the concentrations chosen here have a protective effect on the whole liver during freezing.

Riboflavin synthesis genes are linked with the lux operon of Photobacterium phosphoreum

Four genes immediately downstream of luxG in the Photobacterium phosphoreum lux operon (ribEBHA) have been sequenced and shown to be involved in riboflavin synthesis. Sequence analyses and complementation of Escherichia coli riboflavin auxotrophs showed that the gene products of ribB and ribA are 3,4-dihydroxy-2-butanone 4-phosphate (DHBP) synthetase and GTP cyclohydrolase II, respectively. By expression of P. phosphoreum ribE in E. coli using the bacteriophage T7 promoter-RNA polymerase system, ribE was shown to code for riboflavin synthetase, which catalyzes the conversion of lumazine to riboflavin. Increased thermal stability of RibE on expression with RibH indicated that ribH coded for lumazine synthetase. The organization of the rib genes in P. phosphoreum is quite distinct, with ribB and ribA being linked but separated by ribH, whereas in E. coli, they are unlinked and in Bacillus subtilis, RibB and RibA functions are coded by a single gene.

Use of the translational mobility of a plasma membrane protein to assess fertilization of mouse oocytes and viability of mouse zygotes and two-cell embryos

The fluorescence photobleaching recovery (FPR) technique was used to measure the translational mobility of a glycoprotein recognized by the monoclonal antibody (mAb) S75 in plasma membranes of mouse oocytes, zygotes, and two-cell embryos. Glycoprotein fractional mobility (f) was significantly decreased in membranes of unfertilized oocytes compared to zygotes or two-cell embryos (f values, 46 +/- 2 and 65 +/- 2%, respectively; p < 0.0001). Reduced apparent glycoprotein mobility was also observed in morphologically degenerated zygotes and two-cell embryos compared to viable zygotes and two-cell embryos (f values, 8 +/- 1 and 60 +/- 3%, respectively; p < 0.0001). These results indicate that the FPR technique can be used to assess oocyte fertilization and preimplantation embryonic viability. This method may be useful in the evaluation of embryonic viability following in vitro fertilization and in the detection of toxic effects of novel compounds on embryonic development.

Protein synthesis and ecdysteroidogenesis in prothoracic glands of the tobacco hornworm (Manduca sexta): stimulation by big prothoracicotropic hormone

The 28-kDa size variant of prothoracicotropic hormone (big PTTH) stimulates ecdysteroidogenesis by prothoracic glands of Manduca sexta. In the present studies, big PTTH stimulated in vitro incorporation of [35S]methionine into proteins of prothoracic glands from Day 7 last instar larvae. In 2-hr incubations, big PTTH elicited an approximately 2-fold increase in total protein-specific activity. The effect appeared to be tissue specific, as big PTTH had no effect on incorporation of label into proteins of control tissue (fat body). Electrophoretic separation of tissue homogenates, followed by autoradiography and densitometric analysis, revealed increased incorporation of radiolabel into numerous glandular proteins. The result suggested that the effect of big PTTH was a general stimulation of protein synthesis, not specific stimulation of a subset of glandular proteins. Big PTTH-stimulated ecdysteroidogenesis was inhibited by cycloheximide, indicating that the increase in protein synthesis is a requisite for enhanced hormone production. Analysis of gland incubation media revealed numerous radiolabeled proteins. The effect of big PTTH on incorporation of [35S]methionine into media proteins was considerably more variable than the effect of big PTTH on tissue incorporation. The result is consistent with the hypothesis that prothoracic glands may release proteins in addition to ecdysteroids.

The nitric oxide donor, sodium nitroprusside, increased intranuclear and cytosolic free calcium concentration in single PU5-1.8 cells

In the present study, the effect of sodium nitroprusside (SNP), a nitric oxide (NO) releasing agent, on the intracellular free calcium concentration ([Ca2+]i) was studied. Our results demonstrate that SNP could increase [Ca2+]i in single PU5-1.8 cells, a murine macrophage cell line, as determined by confocal laser scanning microscope with calcium green-1 fluorescent probe. In the presence of hemoglobin, a NO scavenger, the effect of SNP on the Ca2+ level was suppressed. Our data also show that the intranuclear Ca2+ ([Ca2+]n) was always higher than those in cytosol. Stimulation of cells with 1mM SNP induced an immediate increase of [Ca2+]n with a delayed rise of cytosolic Ca2+ ([Ca2+]c). Interestingly, when cells were subsequently treated with 2mM SNP, an increase of [Ca2+]c with a similar pattern to the rise [Ca2+]n was observed. In Ca(2+)-free buffer, SNP also raised the [Ca2+]n and [Ca2+]c. When Ca2+ was added to the buffer, a second peak of [Ca2+]n and several spikes of [Ca2+]c were observed. These results thus indicate that 1) NO may increase both [Ca2+]n and [Ca2+]c in PU5-1.8 cells; 2) the increase of [Ca2+]n requires both internal and external Ca2+. Moreover, the diverse responses in these cells suggest that the regulation of Ca2+ in these areas may be different.

Differential diagnosis of extrahepatic biliary atresia from neonatal hepatitis: a prospective study

The clinical presentations of cholestasis in infancy caused by neonatal hepatitis and biliary atresia are very similar. Diagnosis may be difficult on many occasions, but the surgical treatment of biliary atresia should be performed as early as possible. We established a 3-day workup protocol for the differential diagnosis of biliary atresia and neonatal hepatitis and compared the diagnostic accuracy, sensitivity, specificity, and predictive values of various methods. One hundred and twenty-six infants, including 84 with neonatal hepatitis (age, 65.1 +/- 24.1 days) and 42 with biliary atresia (age, 60.3 +/- 31.1 days), were studied prospectively from July 1982 to December 1990. The diagnostic accuracy of various methods was as follows: liver histology, 96.8%; color of duodenal juice, 91.6%; peak radioisotope count in duodenal juice, 84.2%; ultrasonographic examination of the hepatobiliary system, 80.2%; and persistence of clay-colored stool, 80.2%. After stepwise logistic regression, the diagnostic methods of significance were liver biopsy, color of duodenal juice, abdominal ultrasonography, and stool color. However, stool color and the onset of jaundice could not differentiate severe neonatal hepatitis from biliary atresia. The diagnostic methods of significance then were liver biopsy and duodenal juice color. With this 3-day protocol, no biliary atresia was missed although four cases of neonatal hepatitis were misdiagnosed, resulting in unnecessary laparotomy; we found an overall diagnostic accuracy of 96.8%. We conclude that this 3-day diagnostic protocol is very helpful in the differential diagnosis of neonatal hepatitis and biliary atresia. Liver histologic examination is the most reliable single test for the differential diagnosis.

Rapid growth of Lymnaea viridis, the intermediate host of Fasciola hepatica, under laboratory conditions

Reported in this communication is a unusually rapid growth of Lymnaea viridis, the intermediate host of Fasciola hepatica, maintained in the laboratory for experimental purposes. When the snails were fed on blue-green algae at about 20 degrees C, they attained a shell length of 12 mm in 37 days from the date of hatching. The snails began laying eggs from 18 to 24 days following hatching.

Characteristics of the Hopfield associative memory utilizing isomorphism relations

Isomorphism relations are utilized to analyze the Hopfield associative memory. When the number of fundamental memories m=/<3, it is proved that two Hopfield associative memories are isomorphic if they have the same mutual distances between the fundamental memories. The number of stable states and the synchronous convergence time of a Hopfield associative memory are shown to be less than or equal to 2 to the power 2(m-1) and 4 to the power 2(m-1), respectively, where m>/=1.

Protection against oxygen toxicity by tracheal insufflation of endotoxin: role of Mn SOD and alveolar macrophages

Endotoxin and the cytokines, tumor necrosis factor and interleukin-1, are known to protect adult rats against O2 toxicity. However, whether the effect of endotoxin is mediated through its direct effect on lung cells or through cytokines is not clear. In this study, we demonstrated that endotoxin at a dosage of 5 micrograms/rat (14-20 micrograms/kg) attenuated O2-induced pulmonary injury and markedly prolonged the survival of rats exposed to 100% O2. Endotoxin was more protective when given by intratracheal insufflation or intravenous injection than by intraperitoneal injection. The endotoxin-induced O2 tolerance was associated with a selective enhancement of pulmonary manganese superoxide dismutase, but not Cu,Zn SOD, mRNA. In addition, depletion of 84% rat alveolar macrophages by liposome-encapsulated dichloromethylene diphosphonate, resulted in a marked reduction (86%) of endotoxin-induced release of tumor necrosis factor into the alveolar space. However, endotoxin was still protective in these alveolar macrophage-depleted animals.

Acute hemiplegia in infancy and childhood

From 1982 to 1991, there were 57 patients diagnosed with various intracranial disorders manifested initially with acute hemiplegia at the Department of Pediatrics, National Taiwan University Hospital. There were 33 boys and 24 girls, aged 12 days to 18 years old. In etiological consideration, cerebrovascular disease (66.7%), intracranial tumors (12.3%) and head trauma (10.5%) accounted for most of the cases. Besides acute hemiplegia, cranial nerve palsy (47.4%), disturbed consciousness (42.1%), headache (42.1%), vomiting (31.6%), focal seizure (21.1%) and fever (21.1%) were also common manifestations. Neuroimage studies of CT/MRI scan and angiography were the most useful diagnostic tools. Treatment modalities included medical treatment in 25 patients and surgical intervention in 16 patients and supportive treatment in the others. There were 12 fatal cases, half of whom died directly of intracranial pathology. The survivors exhibited various neurological deficits, in which motor deficits, mental retardation, and subsequent seizures were the three most common sequelae.