Inhibition of glucose uptake and suppression of glucose transporter 1 mRNA expression in L929 cells by tumour necrosis factor-alpha

Recombinant human tumour necrosis factor-alpha (rhTNF-alpha) arrested the growth and suppressed glucose uptake of mouse fibrosarcoma L929 cells in vitro. When the cells were treated with rhTNF-alpha for 24 hours, the mRNA level of glucose transporter 1 (GLUT 1), which is the only GLUT found to be present in L929 cells in our study, was suppressed in a dose-dependent manner. Since the growth of tumour cells depends mainly on glucose catabolism, our findings may indicate that rhTNF-alpha inhibits L929 cells growth by lowering the glucose transport through suppression of GLUT 1 mRNA expression in the cells.

Clinical features and risk factors of pulmonary oedema after enterovirus-71-related hand, foot, and mouth disease

BACKGROUND

In Taiwan, from April to July, 1998, an epidemic of hand, foot, and mouth disease associated with enterovirus 71 (EV71) occurred with fatal complications. We did a clinical study of EV71-related diseases in Taiwan.

METHODS

We studied 154 children with virus-culture confirmed EV71 infection. Children were divided into three groups: 11 patients with pulmonary oedema; 38 patients with central nervous system (CNS) involvement and no pulmonary oedema; and 105 children without complications. We compared the clinical features, laboratory findings, risk factors, and outcome among these three groups.

FINDINGS

Nine children with pulmonary oedema had hand, foot, and mouth disease, one had herpangina, and one had febrile illness with eight children with limb weakness and one with limb hypesthesia. All children had had sudden onset of tachycardia, tachypnoea, and cyanosis 1-3 days after onset of the disease. Nine of 11 children died within 12 h of intubation; one child was braindead within 15 h and died 17 days after intubation; one child was in deep coma and died 3 months later. In children with CNS complication and no pulmonary oedema, one child died of pneumonia after 4 months of ventilator support and four children had sequelae. All 105 children without complications recovered. There was a significant association between CNS involvement and pulmonary oedema (odds ratio 12.4 [95% CI 2.6-60.1], p=0.001). Risk factors for pulmonary oedema after CNS involvement were hyperglycaemia, leucocytosis, and limb weakness. Hyperglycaemia was the most significant prognostic factor for pulmonary oedema (odds ratio 21.5 [3-159], p=0.003).

INTERPRETATION

EV71 can cause hand, foot, and mouth disease, CNS involvement with severe sequelae, and fatal pulmonary oedema. Hyperglycaemia is the most important prognostic factor.

A histological analysis of liver injury in freezing storage

As part of a more extensive study on the use of high subzero freezing for cryopreservation of mammalian livers we have tried to single out the effects of freezing and thawing on tissue damage. We compared the morphology of livers after freezing and thawing with what we considered an optimal high subzero cryopreservation protocol with the morphology of livers preserved under the same thermal conditions and in the same solution in a supercooled state, without freezing. The results show that while hepatocytes survive high subzero cryopreservation, detachment of endothelial cells occurs in every freezing experiment. On the other hand, the endothelial cells in livers that are not frozen are intact. This suggests that endothelial cell damage is caused by freezing and may be an important factor in high subzero freezing cryopreservation of the liver.

Source memory in Parkinson's disease

Three experiments (ns = 14 per group) are reported which investigated the ability of Parkinson patients to remember the characteristics of conditions under which a memory was acquired. In Exp. 1, subjects were required to indicate for each item in a recognition memory test whether it was spoken by Experimenter 1 or by Experimenter 2 (external-external source memory). In Exp. 2, subjects had to indicate for each item whether it was generated by themselves or by the experimenter (internal-external source memory). In Exp. 3, subjects had to judge whether an item was generated by themselves in saying or in thinking (internal-internal source memory). We found that patients with Parkinson's disease were not impaired in the previous two kinds of source memory (Exp. 1 and 2) but were impaired in internal-internal source memory (Exp. 3) relative to the age-matched control groups. In addition, both groups' performance could be improved when given distinctive cues, i.e., perceptual cues in Exp. 1 and different-domain cues in Exp. 2. These results suggest that the availability of cues was critical for Parkinson's disease in source memory. Finally, the result of Exp. 2 also showed generation effects for patients with Parkinson's disease. The generation effect refers to better memory of information by people when they had to produce it, e.g., producing associates to a word, compared with memory of information given to them.

Characterization of a brain-specific nuclear LIM domain protein (FHL1B) which is an alternatively spliced variant of FHL1

We have amplified and sequenced a novel, alternatively spliced variant of a human gene coding for the four-and-a-half LIM domain protein 1 (FHL1). This gene is located at chromosome Xq27 and the spliced variant is named FHL1B. The ORF of FHL1B cDNA codes for a LIM-only protein that possesses a zinc finger and three tandem repeats of LIM domains at the N-terminus with an active bipartite nuclear localization signal (NLS) motif and a possible RBP-J binding region at the C-terminus. FHL1B and FHL1 have the same N-terminal three-and-a-half LIM domains but different C-terminal protein sequences, due to the presence of an additional alternative exon 4b in FHL1B causing a frame-shift in the 3'coding region. RT-PCR results revealed that the expression of FHL1 is not restricted in skeletal muscle and heart, but is widely distributed in other tissues, including brain, placenta, lung, liver, kidney and pancreas, albeit as a low abundance transcript. In contrast, FHL1B is specifically expressed in brain. The C-terminal alternative region in FHL1B is sufficient to localize FHL1B in the nucleus of mammalian cell. FHL1B is probably related to neural differentiation and certain fragile X syndrome.

An incidental case of human Heterophyes nocens infection diagnosed by sectional morphology in a biopsy specimen of the small intestine

A case of human infection with Heterophyes nocens (Heterophyidae) was incidentally found in a biopsy specimen of the Meckel's diverticulum at the upper part of the small intestine. The patient was a 58-year-old man living in a rural area of Talsonggun, Kyongsangbuk-do. He had gastrointestinal symptoms such as epigastric pain, indigestion, and abdominal discomfort for 3 months, and severe diarrhea, abdominal pain, and vomiting for about 1 month before hospitalization. Endoscopy of the upper part of the small intestine revealed a Meckel's diverticulum, and it was excised and histopathologically examined. Three adult flukes were incidentally found sectioned in the mucosa, and they were identified as H. nocens. The patient had a history of eating raw mullets at a fish market in Pusan 6 months ago, and the mullets were presumed to be the source of infection. This case brings a considerable interest in that specific diagnosis of heterophyid infections could be done by sectional morphology of the worms.

Typhoid fever presenting as infection-associated hemophagocytic syndrome: report of one case

This report describes a 13-year-old boy who had high fever with severe pancytopenia and acute psychosis as initial presentation. Bone marrow examination was compatible with infection-associated hemophagocytic syndrome (IAHS). Blood culture showed no growth of bacteria while the culture of bone marrow yielded Salmonella typhi. The clinical condition stabilized shortly after the use of ceftriaxone. This case illustrates that typhoid fever must be included in the differential diagnosis of IAHS. In cases with IAHS, bacterial culture as well as morphological study of bone marrow is necessary for the evaluation of etiological agent and to avoid injudicious use of chemotherapy.

Determination of organochlorine pesticide residues in foods using solid-phase extraction clean-up cartridges

Fourteen organochlorine pesticide residues in fatty foods were determined using a simple and rapid procedure based on solid-phase extraction (SPE) clean-up cartridges with octadecyl (C18)-bonded porous silica, a tandem C18 and Florisil column, Alumina-N and Florisil. A Florisil cartridge eluted with 12 ml petroleum ether-ethyl ether (95 + 5) was the most efficient clean-up procedure capable of eliminating the matrix interference and satisfying the agreed acceptable recovery for the large numbers of organochlorine pesticides in nine kinds of foods having different fat contents. Average recoveries of organochlorine pesticides in shellfish, fish and meats ranged from 77 to 105%, 84 to 98% and 85 to 107%, respectively. In addition, analysis of a certified Standard Reference Material (SRM 1945) verified the satisfactory performance of Florisil clean-up cartridge. This SPE method not only yielded comparable results for nonfatty foods, but also provided a reliable separation and quantification of organochlorine pesticides for analyzing a large number of foods with a wide range of fat content.

Penicillin-nonsusceptible Streptococcus pneumoniae infections in children

The emergence of penicillin-nonsusceptible Streptococcus pneumoniae (PNSSP) has brought a new clinical challenge. In Taiwan, reports of the prevalence and clinical features of PNSSP infections in children are limited. This study reviewed the resistance patterns of all clinical isolates of S. pneumoniae obtained from patients under 17 years of age from January 1993 through July 1998 in a medical center. Their clinical features and treatment responses were analyzed, with special attention paid to those patients with invasive PNSSP infections. Totally, 170 clinical isolates of S. pneumoniae were obtained from 168 patients aged under 17 years. Among those infections, there were 56 sinusitis (including 4 sinusitis with bacteremia), 44 pneumonia (including 23 pneumonia with bacteremia or empyema), 23 otitis media (including 5 otitis media with bacteremia), 9 simple bacteremia, 9 conjunctivitis, 8 meningitis, 4 peritonitis, 3 skin infections and the other 14 isolates were colonization. One hundred eleven isolates (65.3%) showed reduced penicillin susceptibility by the disk diffusion method. A trend of increasing percentiles of PRSP was noted: 27.3% (3/11) in 1993, 37.5% (9/24) in 1994, 55.5% (10/18) in 1995, 77.5% (31/40) in 1996, 66.0% (31/47) in 1997, and 87.1% (27/31) in 1998. Minimum inhibitory concentration (MIC) determinations by the E-test showed some of the isolates were intermediately resistant. Prior antibiotic usage was associated with a higher incidence of PNSSP infections. However, most children responded well to antimicrobial treatment.

Enhanced cytotoxicity and suppression of glucose transport rate by combined treatment of recombinant human tumour necrosis factor-alpha and hyperthermia on L929 cells

Combined treatment with human recombinant TNF-alpha (rhTNF-alpha) and hyperthermia at 43 degrees C arrested the growth of mouse fibrosarcoma L929 cells in vitro. The cytotoxic effect was enhanced in combined treatment compared with that following administration of rhTNF-alpha or hyperthermia alone. When the cells were subjected to hyperthermia at 43 degrees C for 3 hours and then incubated with 0.4 ng/ml rhTNF-alpha at 37 degrees C for 24 hours, a statistically significant 65% decrease in the rate of cellular glucose uptake was observed. This suppressive effect was synergistic in terms of effect achieved by rhTNF-alpha or hyperthermia individually. Since the growth of tumour cells depends mainly on catabolism of glucose, our findings indicate that one manner by which combined rhTNF-alpha and hyperthermia treatment inhibits L929 cell growth may be by reducing the supply of glucose to the cells.

Cytochrome P450 MA expression in insecticide-resistant German cockroaches (Dictyoptera: Blattellidae)

Cytochrome P450 monooxygenases are detoxification enzymes commonly involved in insecticide resistance by insects. Recently, an overexpressed form of this enzyme, P450 MA, was purified from an insecticide-resistant strain of German cockroach, Blattella germanica (L.), and polyclonal antisera (anti-P450 MA) was produced. To test hypotheses that the overexpressed condition of P450 MA has evolved in > 1 geographic location and that P450 MA might be involved in insecticide resistance to specific insecticides, investigations were conducted using 4 insecticide-resistant and 1 susceptible German cockroach strains. In western blots that used anti-P450 MA antiserum as a probe, substantial differences in expression of P450 MA were observed. Strains showing the highest P450 MA expression had both the highest tolerance to the organophosphate insecticide chlorpyrifos and cytochrome P450-mediated demethylation activity. Results support the hypothesis that cytochrome P450 MA is potentially overexpressed in insecticide-resistant populations on a global scale.

Functional analysis of the Staphylococcus aureus collagen adhesin B domain

The Staphylococcus aureus collagen adhesin (CNA) occurs in at least four forms that differ in the number (one, two, three, or four) of B domains. The B domains contain 187 amino acids and are located between the domains that anchor CNA to the cell envelope and the ligand-binding A domain. To determine whether a B domain is required for functional expression of CNA, we cloned the 2B cna gene from S. aureus strain Phillips and then eliminated both B domains by overlapping PCR. The absence of a B domain did not affect processing of the collagen adhesin to the cell surface or the ability to bind collagen. Based on our recent demonstration that the capsule can mask CNA on the surface of S. aureus cells (A. F. Gillaspy et al., Infect. Immun. 66:3170-3178, 1998), we also investigated the possibility that multiple B domains can extend the ligand-binding A domain outward from the cell surface and thereby overcome the inhibitory effect of the capsule. Specifically, we cloned the naturally occurring 4B CNA variant from S. aureus UAMS-639 and, by successive elimination of B domains, generated 1, 2, and 3B variants that are isogenic with respect to the 4B clone. After introducing each variant into microencapsulated and heavily encapsulated strains of S. aureus and growing cells under conditions known to affect capsule production (e.g., growth on Columbia agar), we correlated capsule production with exposure of CNA on the cell surface and the ability to bind collagen. Under no circumstance was the masking effect of the capsule reduced by the presence of multiple B domains. These results indicate that the B domains do not extend the ligand-binding A domain outward in a fashion that can overcome the inhibition of collagen binding associated with capsule production.

Inhibition of glucose transporter gene expression by antisense nucleic acids in HL-60 leukemia cells

Glucose is the basic source of energy for mammalian cells. The energy-independent transport of glucose down its concentration gradient is mediated by the facilitative glucose transporter family (GLUT). It has long been recognised that glucose transporter genes are overexpressed in many human cancer cells, to help provide extra energy for the rapid growth of cancer cells. In the present study, antisense oligonucleotides and plasmid-derived antisense RNA against GLUT-1 gene were synthesized and transfected into human leukemia HL-60 cells to investigate the effect of these antisense nucleic acids on tumour growth. Our results show that antisense nucleic acids inhibited the proliferation of HL-60 cells by 50-60% and the mRNA expression of GLUT-1 gene was suppressed as detected by Northern hybridization.

Croup syndrome in children: five-year experience

To investigate the etiology and clinical features of croup syndrome, clinical records of hospitalized children with a diagnosis of croup syndrome were reviewed from April 1990 to January 1996. There was a total of 132 children, aged between three months and seven years with a mean age of 21.3 +/- 16.8 months. A diagnosis of laryngotracheobronchitis was made in 123 (93.2 percent) children. Twenty-three pathogens were identified in twenty-two of them, including seven parainfluenza viruses, five respiratory syncytial viruses, four influenza A viruses, four Mycoplasma pneumoniae, and three adenoviruses. Bacterial tracheitis was confirmed by bronchoscopic examination in seven cases (5.3 percent). Cultures of the respiratory secretions yielded viridans streptococci in six and Staphylococcus aureus in one child. Two children (1.5 percent) had spasmodic croup. No case with epiglottitis was noted in the present study. A fever lasting for more than three days was noted in five (71 percent) children with bacterial tracheitis and thirty-five (28 percent) children with laryngotracheobronchitis (p = 0.048). Among children with laryngotracheobronchitis, an associated diagnosis of pneumonia, acute otitis media, or paranasal sinusitis was more frequently observed in those with fever > 3 days (40 percent) than those with a shorter duration of fever (17 percent, p = 0.013). In conclusion, a child with a longer duration of fever and more severe manifestations of airway obstruction probably has a bacterial cause of croup syndrome or a bacterial complication. Bacterial tracheitis is more common than epiglottitis in Taiwan.

Kinetics of enamel demineralization in vitro

Previously, we reported that the rate (R) of hydroxyapatite dissolution in acetic, lactic, and phosphoric acid solutions is a function of the degree of saturation with respect to the dissolving mineral, DS (defined as the ratio of the mean ionic activity product for hydroxyapatite [Ca5OH(PO4)3] in solution to its solubility product constant), and the sum of the acid activities (sumBiH) in solution: R = K(1-DS)m(sumBiH)n. The present study was undertaken to explore the general validity of this model in describing the kinetics of enamel demineralization. Thin sections of human enamel were exposed to partially saturated 0.1 mol/L lactic acid solutions, at two different DS levels, and at pH values of 4.3 to 6.0. Thin sections of human enamel were also exposed to solutions with four different concentrations of acetic and lactic acids (pH 4.3) with three different DS values and, at one DS value, to solutions of propionic acid. Mineral loss was monitored by quantitative microradiography. In solutions with pH values of 4.3 and 5.0, "lesions" were formed with well-defined surface layers, whereas, in solutions with pH 6.0, "lesions" were produced with no apparent surface layers. The formation of relatively intact surface layers was consistent with predicted phase transformations. Rates of mineral loss were found to be inversely proportional to both the degree of saturation with respect to enamel mineral, DS(En), and the pH of the solution and increased with increased activities of each organic acid, consistent with the proposed model. However, at the same DS(En) and acid activity, rates of demineralization were the same in the acetic and propionic acid solutions, whereas rates of demineralization in lactic acid were greater. It is suggested that specific interactions of acid species with enamel mineral may modify the rate of enamel demineralization. These in vitro findings suggest that relatively small differences in DS(En) values found in plaque fluid may result in very significant differences in the rate of enamel demineralization in vivo.

Sequence analysis of VP1 and VP7 genes suggests occurrence of a reassortant of G2 rotavirus responsible for an epidemic of gastroenteritis

G2 rotavirus was prevalent in a 1993 epidemic of acute gastroenteritis in Taiwan. In this study, the genetic relationship among G2 rotavirus strains was analysed. The VP7 genes were amplified and sequenced. Except for one strain isolated in 1981, the nucleotide sequences of the VP7 genes of most of the G2 rotaviruses were very similar (identity > 97%) and were closely related to that of a Japanese G2 reference strain, S2. The genetic relatedness of G2 rotaviruses was analysed further by RNA-RNA hybridization. The genomes of the major G2 strains of 1993 did not hybridize well with those of the G2 strains of previous seasons in RNA segments 1, 6 and 7. Partial nucleotide sequences of the VP1 gene were analysed and appeared to be similar among the major G2 strains from the same epidemic (identity > 98%), whereas the identity of the VP1 genes of the major G2 strains of the 1993 epidemic to those of previous seasons was only about 84%. Since the numbers of mutations accumulated in the VP1 and VP7 genes over a period of 10 years were comparable, the significant change in the VP1 genes of the major strains of the 1993 epidemic suggests that these G2 rotaviruses had evolved by genetic reassortment.

Toxicological and antioxidant effects of short-term dehydroepiandrosterone injection in young rats fed diets deficient or adequate in vitamin E

This study examined the in vivo antioxidant and/or prooxidant effect of short-term dehydroepiandrosterone (DHEA) injection and the effect of dietary vitamin E. Male Sprague-Dawley rats (4 wk old) were fed vitamin E-deficient or vitamin E-adequate (30 mg DL-alpha-tocopheryl acetate/kg) diet for 4 weeks followed by intraperitoneal injection of DHEA for 1 week. The results showed that DHEA injection caused a dose-dependent decrease in body weight, and this effect was more pronounced in vitamin E-deficient rats. In contrast, DHEA injection significantly increased liver, kidney and adrenal weights. Hepatic vitamin E content was significantly lowered by vitamin E deficiency, which led to significantly increased ex vivo and iron-induced lipid peroxidation. DHEA injection did not affect hepatic vitamin E content but significantly decreased ex vivo and iron-induced lipid peroxidation in vitamin E-deficient rats. Hepatic total sulfhydryl (SH) groups and non-protein SH contents were not affected by vitamin E but were significantly increased by DHEA injection, which at 100 mg/kg was not more effective than at 50 mg/kg. Hepatic glutathione S-transferase (GST) activity was significantly decreased by DHEA, but vitamin E alleviated such a decrease. DHEA injection significantly increased hepatic glucose 6-phosphate dehydrogenase (G6PD) activity, and the effect was dose dependent in vitamin E-deficient rats. Thus, DHEA may compensate for vitamin E deficiency in vivo, and this effect is masked when dietary vitamin E is adequate. The antioxidant effect of DHEA is accompanied by decreased body weights, enlarged (fat-laden) tissues and altered activities of hepatic GST and G6PD.

Dietary intake and residues of organochlorine pesticides in foods from Hsinchu, Taiwan

The levels of contamination with various organochlorine pesticides (such as total HCH, heptachlor, heptachlor epoxide, aldrin, dieldrin, endrin, endosulfan, and total DDT) of different foods from 3 traditional markets were determined to estimate Taiwanese daily intake of organochlorine pesticides. Of the 18 organochlorine pesticides investigated, alpha-HCH, beta-HCH, lindane, delta-HCH, heptachlor, heptachlor epoxide, dieldrin, endrin, alpha-endosulfan, p,p'-DDE, and p,p'-DDT were detected at concentrations ranging from 0.26 to 10.2 ng/g wet weight. Contamination with organochlorine pesticides followed the order heptachlor > dieldrin > alpha-endosulfan > HCH isomers > heptachlor epoxide > DDT. Frequencies of detection of organochlorine pesticide residues ranged from 2.0 to 52.3%. alpha-Endosulfan was the most frequently detected organochlorine pesticide in the foods analyzed, followed by heptachlor epoxide (47.6%) and alpha-HCH (38.9%). Estimated daily intakes (EDIs) of organochlorine pesticides from foods were 1.137 micrograms for total HCH, 2.147 micrograms for heptachlor, 0.702 microgram for heptachlor epoxide, 0.624 microgram for endosulfan, 0.098 microgram for cyclodiene, and 0.541 microgram for total DDT. These EDIs were only 0.075% of the acceptable daily intake (ADI) for lindane, 47.5% of ADI for heptachlor and heptachlor epoxide, 0.045% of ADI for total DDT, and 1.01% of ADI for aldrin and dieldrin. Therefore, consumption of the foods analyzed does not pose a risk to consumer health.

Promoter analysis of the cap8 operon, involved in type 8 capsular polysaccharide production in Staphylococcus aureus

The production of type 8 capsular polysaccharide (CP8) in Staphylococcus aureus is regulated in response to a variety of environmental factors. The cap8 genes required for the CP8 production in strain Becker are transcribed as a single large transcript by a primary promoter located within a 0.45-kb region upstream of the first gene of the cap8 gene cluster. In this study, we analyzed the primary cap8 promoter region in detail. We determined the transcription initiation site of the primary transcript by primer extension and identified the potential promoter sequences. We found several inverted and direct repeats upstream of the promoter. Deletion analysis and site-directed mutagenesis showed that a 10-bp inverted repeat of one of the repeats was required for promoter activity. We showed that the distance but not the specific sequences between the inverted repeat and the promoter was critical to the promoter activity. However, insertion of a DNA sequence with two or four helix turns in this intervening region had a slight effect on promoter activity. To demonstrate the biological significance of the 10-bp inverted repeat, we constructed a strain with a mutation in the repeat in the S. aureus Becker chromosome and showed that the repeat affected CP8 production mostly at the transcriptional level. By gel mobility shift assay, we demonstrated that strain Becker produced at least one protein capable of specific binding to the 10-bp inverted repeat, indicating that the repeat serves as a positive regulatory protein binding site. In addition, reporter gene fusion analysis showed that the cap8 promoter activity was influenced by various growth media and affected most by yeast extract. Our results suggest that yeast extract may exert its profound inhibitory effect on cap8 gene expression through the 10-bp inverted repeat element.

In vivo and in vitro association of 14-3-3 epsilon isoform with calmodulin: implication for signal transduction and cell proliferation

Using a yeast two-hybrid screen, human 14-3-3 epsilon protein was found to interact with human calmodulin. In vitro binding assay between human 14-3-3 epsilon protein/peptide and calmodulin was demonstrated by native gel electrophoresis, and the interaction was shown to be calcium dependent. Our results, along with the association of the 14-3-3 epsilon protein with other signaling proteins, suggest that the 14-3-3 protein could provide a link between signal transduction and cell proliferation.

Pertussis toxin-induced lung edema. Role of manganese superoxide dismutase and protein kinase C

The mechanism by which pertussis toxin (Ptx) causes lung edema is not clear. We investigated the role of pulmonary manganese superoxide dismutase (MnSOD) and protein kinase C (PKC) in Ptx-induced lung edema. We demonstrated that intraperitoneal injection of Ptx at a concentration of 5 microg/100 g body weight caused a similar degree of lung edema in 2 d, as measured by lung wet weight/dry weight ratio, in heterozygous MnSOD gene (Sod2)-knockout mice (Sod2(+/-)) and in their wild-type littermates (Sod2(+/+)). The level of lung MnSOD activity in Sod2(+/-) mice was approximately half that of Sod2(+/-) mice. Ptx had no effect on levels of lung MnSOD messenger RNA, immunoreactive protein, or enzyme activity in either Sod2(+/+) or Sod2(+/-) mice. Ptx also had no effect on lung copper-zinc SOD, catalase, and glutathione peroxidase activities in these mice. On the other hand, Ptx caused the activation of lung PKC, for example, by translocation of a 72-kD PKC isoform from the cytosolic fraction to the membrane fraction. Pretreatment of mice with bisindolylmaleimide, a PKC inhibitor, prevented both the Ptx-induced activation of PKC and lung edema. These data suggest that Ptx-induced lung edema in mice is, at least in part, due to the activation of lung PKC.

Radiation hybrid mapping of human cytosolic malate dehydrogenase (hcMDH) to the short arm of chromosome 2

Compartmentalization of human cytosolic malate dehydrogenase, hcMDH, together with its isozyme partner-mitochondrial form, hmMDH, plays an important role in the aerobic metabolism of the malate-aspartate shuttle and the citric acid cycle. However, they share few structural homology at the molecular level. The pseudogenes of mMDH has been reported in mice but hcMDH has no pseudogenes as shown by Southern blot analysis. A single band only was detected for the EcoRI digestion with 9.4 kb long of human genomic DNA and HindIII cutting with 2.8 kb long. hcMDH gene was mapped to chromosome 2 by somatic cell hybrid analysis and further localised to 268.72 cR from the top telomere of Chromosome 2 (near 2p15) by radiation hybrid mapping. The genes falling into this region may be related to dilated cardiomyopathy (DCM), several types of cancers and immunoregulation mechanism of cancers.

Anaesthesia Incident Monitoring Study in Hospital Kuala Lumpur--the second report

Critical incident reporting is a useful quality improvement technique for reducing morbidity and mortality in anaesthesia. This study analyses 93 cases in Kuala Lumpur Hospital from July 1995 to January 1997. The main incidents during anaesthesia in this study were airway incidents. While human error was identified as the main factor contributing to the occurrence of adverse incidents. Critical incident monitoring plays an important role in identifying potential problems, which may lead to disaster. The findings from this report of the anaesthesia incident monitoring study continued to indicate the occurrence of similar problems seen in an earlier report. The identification of common incidents can be used to identify risk factors and minimise repetition of such incidents.

Long-term response to hepatitis B vaccination and response to booster in children born to mothers with hepatitis B e antigen

Hepatitis B (HB) vaccine provides an uncertain duration of protection and the optimal timing of booster vaccine remains unclear. This study examined the immune response at 10 years of 118 children who had developed protective anti-HB surface (anti-HBs) levels after a primary series of HB immunizations in infancy. All of the children were born to hepatitis B e Antigen (HBeAg)-positive hepatitis B surface antigen (HBsAg) carrier mothers. HB markers in all subjects and cellular immune response in some were determined. A booster was given to all subjects after the collection of samples and another blood sample was collected 4 weeks later. The results showed that a total of 39 (33%) of the children were seronegative for anti-HBs. T-cell proliferative response to HBsAg was noted in 47% of children. On HBsAg stimulation, leukocyte samples from a significantly higher proportion of subjects produced cytokines (81% of T cells produced interleukin-2 [IL-2] and 100% produced IL-5). The booster dose of HB vaccine induced the production of a protective level of anti-HBs (>/=10 mIU/mL) in all subjects. Cellular immunity was augmented with a positive rate of 58%, 90%, and 100% for HBsAg-induced T-cell proliferation, IL-2 production, and IL-5 production, respectively. Although 14 (11.9%) of the subjects were HB core antibody positive at 10 years of age, no new HBsAg carrier was detected. The results of this study show that protection afforded by HB vaccination persisted to the age of 10 years in all vaccinees. Immunologic memory was detected in all subjects including those who had lost their anti-HBs seropositivity. These results suggest that no booster vaccination is needed before 10 years of age. The most sensitive marker of immunologic memory is IL-5 production of T cells. (HEPATOLOGY 1999;29:954-959.)

Cloning and characterization of a cDNA encoding a novel fibroblast growth factor preferentially expressed in human heart

A novel human fibroblast growth factor (hFGF), which shows 75% sequence homology with fibroblast growth factor-9, was isolated in random sequencing of a human heart cDNA library. The full-length sequence is 928 bp, the encoded protein is composed of 168 amino acid residues, and its pI value and molecular weight were estimated to be 8.13 and 19.1 kDa, respectively. RT-PCR using Marathon human heart cDNA shows that the coding region is approximately 507 bp. Southern hybridization showed a single band which indicates that this is a single copy gene. Northern hybridization done on a human multiple tissues blot showed that the gene is preferentially expressed in human heart, very weakly detectable in human brain and not detectable in 18 other different human tissues.

The absence of 150-kDa insulin-like growth factor complexes in fetal rat serum is not due to a lack of functional acid-labile subunit

Most of the insulin-like growth factors (IGFs) in adult rat or human plasma circulate in 150-kDa heterotrimeric complexes with IGF-binding protein-3 (IGFBP-3) and an acid-labile subunit (ALS). These 150-kDa complexes are not present, however, in rat serum at birth. As ALS is the critical determinant in the formation of the 150-kDa complexes in adult rat serum, the present study asks whether the absence of 150-kDa complexes in fetal rat serum results from a low abundance of ALS. We report that ALS mRNA is expressed in term fetal rat liver at 30% of the levels in adult liver, that radioiodinated rat ALS is not proteolyzed by incubation with fetal rat serum, and that sufficient functional ALS is present in fetal rat serum to form 150-kDa complexes with recombinant human IGFBP-3. These results indicate that the low levels of 150-kDa complexes in perinatal rat serum are not due to low circulating levels of ALS.

Proteolysis of insulin-like growth factor binding protein-3 in serum from pregnant, non-pregnant and fetal rats by matrix metalloproteinases and serine proteases

The insulin-like growth factors (IGFs) in adult mammalian plasma circulate predominantly in 150-kDa complexes that also contain IGF-binding protein-3 (IGFBP-3) and an acid-labile subunit. Proteolysis of IGFBP-3 within the 150-kDa complex decreases its affinity for IGFs, facilitating their release to the tissues. By contrast, 150-kDa complexes are not detected in serum from fetal or pregnant adult rats. Decreased complex formation results from insufficient availability of IGFBP-3 due to increased IGFBP-3 proteolysis. The present study characterizes IGFBP-3 protease activity in serum from fetal, pregnant and non-pregnant adult rats by comparing the effect of different protease inhibitors. Proteolysis of exogenous recombinant human IGFBP-3 (for fetal and pregnancy serum) or endogenous IGFBP-3 (for non-pregnant adult rat serum) following incubation at 37 degrees C was measured by ligand blotting. In all three sera, IGFBP-3 proteolysis was inhibited completely by: (i) EDTA, a chelator of divalent cations. Inhibition was reversed by zinc, but not by calcium ions; (ii) 4-(2-aminoethyl)-benzenesulfonyl fluoride (AEBSF), an inhibitor of serine proteases; and (iii) a specific tissue inhibitor of matrix metalloproteinases (TIMP-1). Recombinant human matrix metalloproteinase-3 (MMP-3) proteolyzed recombinant human IGFBP-3 or endogenous rat IGFBP-3 in non-pregnancy serum pretreated with AEBSF to inactivate endogenous serine proteases. These results suggest that serine proteases initiate the activation of latent MMP precursor, and that the activated MMP directly degrades IGFBP-3.

Characterization of the human 36-kDa carboxyl terminal LIM domain protein (hCLIM1)

We characterized a human cDNA clone encoding a 36-kDa carboxyl terminal LIM domain protein with a PDZ domain at the amino terminal. This full-length cDNA clone has a predicted open reading frame (ORF) of 329 amino-acid residues. The ORF of this cDNA encodes the human homolog of rat CLP36, and the putative protein is named human 36-kDa carboxyl terminal LIM domain protein (hCLIM1, nomenclature approved by the HUGO/GDB Nomenclature Committee). The hCLIM1 probe was used to hybridize with poly(A)+ RNA of various human tissues. Strong signals were detected in heart and skeletal muscle; moderate signals were detected in spleen, small intestine, colon, placenta, and lung; weaker levels were detected in liver, thymus, kidney, prostate, and pancreas; and no observable signals were detected in brain, testis, ovary, and peripheral blood leukocytes. The hCLIM1 gene was studied by fluorescence in situ hybridization (FISH), somatic cell hybrid analysis, and radiation hybrid mapping, and it is located at the human chromosome 10q26.

Nonexercise stress transthoracic echocardiography: transesophageal atrial pacing versus dobutamine stress

OBJECTIVES

To compare transesophageal atrial pacing stress echocardiography with dobutamine stress echocardiography for feasibility, safety, duration, patient acceptance and concordance in inducing wall motion abnormalities.

BACKGROUND

Transesophageal atrial pacing is an effective method of increasing heart rate and has been used in the assessment of coronary artery disease.

METHODS

Both tests were performed in sequence on the same patients in random order. Transesophageal atrial pacing stress echocardiography began at a heart rate of 10 beats/min above the baseline value and was increased by 20 beats/min every two min until 85% of the age-predicted maximum heart rate or another end point was reached. Dobutamine echocardiography was performed using three-min stages and a maximum dose of 40 microg/kg per min. Atropine (total dose < or =2 mg) was administered at the start of the 40 microg/kg per min stage if needed to augment heart rate or during pacing if Wenckebach heart block occurred.

RESULTS

Transesophageal atrial pacing stress echocardiography was feasible in 100 of 104 patients (96%); the duration (8.6+/-3.6 min) was significantly shorter than that of dobutamine stress echocardiography (15.1+/-3.9 min) (p = 0.0001). With transesophageal atrial pacing stress echocardiography, the recovery period was shorter, symptoms and dysrhythmias were fewer, hypertension and hypotension were less common and target heart rate was more frequently achieved. No complications occurred with either test. Patient acceptance was satisfactory. Agreement between results of both tests was good for segmental wall motion scoring with a 16-segment model, scores 1 to 5 (kappa: rest, 0.79; peak, 0.57) and test interpretation (normal, ischemia, infarction or resting wall motion abnormality with ischemia) (kappa: 0.77).

CONCLUSIONS

Transesophageal atrial pacing stress echocardiography is a feasible, well-tolerated alternative to dobutamine stress echocardiography. It can be performed rapidly and shows good agreement with dobutamine stress echocardiography in the induction of myocardial ischemia.

An evaluation of the safety and immunogenicity of a five-component acellular pertussis, diphtheria, and tetanus toxoid vaccine (DTaP) when combined with a Haemophilus influenzae type b-tetanus toxoid conjugate vaccine (PRP-T) in Taiwanese infants

OBJECTIVE

Immunologic interference particular to the Haemophilus influenzae type b (Hib) response has been observed with previous acellular pertussis-Hib combination vaccines. To test this hypothesis a clinical trial to assess the safety and immunogenicity of a five-component (pertussis toxoid [PT], filamentous hemagglutinin [FHA], pertactin [PRN], and fimbriae 2 and 3 [FIM]), pertussis vaccine combined with diphtheria and tetanus toxoids (DTaP) when given simultaneously with a lyophilized Hib-tetanus toxoid conjugate vaccine (PRP-T) in infants at 2, 4, 6, and 18 months of age was conducted. The study compared two methods of administration: both vaccines combined in a single syringe and administered as a single injection, or both vaccines administered concurrently but at separate sites of injection.

METHODS

Healthy 2-month-old infants were enrolled at the National Taiwan University Hospital. DTaP, PRP-T, and oral poliomyelitis vaccine (OPV) were given at 2, 4, 6, and 18 months. Reaction information was collected by telephone 2 days after each vaccination. Serum was collected at 2, 6, 7, 18, and 19 months of age.

RESULTS

One hundred thirty-five healthy infants were enrolled in Taiwan, of which 127 (94%) completed the 18-month booster: 68 received the combined vaccine and 67 the separate vaccines. All vaccines were well tolerated. No differences in rates of local and systemic reactions were seen between the two methods of administration. No serious adverse events were reported. Serologic responses were comparable between the groups. Pertussis responses (enzyme-liked immunoabsorbant assay units [EU]/mL) at 7 months were, for combined versus separate, PT (131 vs 105), FHA (116 vs 116), PRN (100 vs 77), and FIM (922 vs 702). At 19 months, pertussis results were, for combined versus separate, PT (216 vs 182), FHA (203 vs 200), PRN (263 vs 197), and FIM (892 vs 732). Only the 7-month PT response in the combined group was significantly higher (combined 131 EU/mL vs separate 105 EU/mL). After the third dose (age 6 months), all subjects achieved serologic serum antibody levels indicative of protection against Hib, diphtheria, tetanus, and poliovirus types 1, 2, and 3. In fact, 96% of children had anti-PRP levels indicative of protection (>/=0.15 microgram/mL) against Hib after only two doses. At 7 months, anti-PRP geometric mean titer values were 11.8 micrograms/mL in the combined group compared with 13.0 micrograms/mL in the separate group. The anti-PRP geometric mean titers after the 18-month booster were 58.5 micrograms/mL in the combined group versus 55.3 micrograms/mL in the separate group.

CONCLUSION

The five-component DTaP vaccine may be combined with PRP-T vaccine without clinically significant immunologic interaction when given in a 2-, 4-, 6-, and 18-month schedule.

Isolation of Eikenella corrodens from polymicrobial hepatic abscess: report of one case

Eikenella corrodens is a rare cause of hepatic abscess. We report a case of a hepatic abscess caused by (1) Bacteroides fragilis, (2) Streptococcus constellatus and (3) E. corrodens, which illustrates potential problems of antibiotic coverage due to the presence of Eikenella species. The infection followed an episode of acute gastroenteritis and the clinical course appeared indolent evolving over one week. Besides empirical antibiotics, initial percutaneous aspiration was performed and yielded pus which grew E. corrodens concomitantly with Streptococcus species. E. corrodens was sensitive to penicillin but resistant to clindamycin and metronidazole. But B. fragilis was resistant to penicillin. So the antibiotics were switched to amoxicillin/clavulanate. Unfortunately fever persisted and the abscess increased in size. Therefore echo-guided percutaneous drainage with pigtail catheter was installed. Fever subsided 5 days later. After 21 days treatment of antibiotics, the patient was discharged in good condition despite having some sterile fluid in the residual abscess cavity. Two months after discharge the follow-up echogram confirmed complete resolution of the residual abscess. This patient shows us the existence of E. corrodens in pediatric patients, especially when the hepatic abscess is very likely from the spread of an oral or abdominal infection.

Molecular-Beam Electric-Resonance Optothermal Spectroscopy Study of the Rotational Spectrum of the Less Stable Conformer of Methyl Vinyl Ether

The pure rotational spectrum of the less stable conformer of methyl vinyl ether has been measured in an electric-resonance optothermal spectrometer. Analysis of the microwave spectrum shows that the less stable conformer is effectively planar with a low barrier between two gauche forms of the conformer. The rotational constants for the high-energy conformer, obtained from a least-squares fit to a threefold barrier internal rotation Hamiltonian are A = 39 192.490(26) MHz, B = 4527.5496(39) MHz, and C = 4181.2146(43) MHz. The threefold barrier to internal rotation is determined to be V3 = 427.516(71) cm-1. The dipole moment for the conformer has been measured using the Autler-Townes splitting of states in a strong, resonant microwave field. The dipole moment is µtot = 1.9(2) D [µa = 1.3(1) D, µb = 1.4(1) D]. The effectively planar structure of the conformer and the magnitude of the dipole moment are in good agreement with previous ab initio calculations. The experimentally determined threefold barrier to methyl rotation of the present study also agrees well with the value calculated from ab initio methods, 515 cm-1. Copyright 1999 Academic Press.

Recombinant acyl-CoA:cholesterol acyltransferase-1 (ACAT-1) purified to essential homogeneity utilizes cholesterol in mixed micelles or in vesicles in a highly cooperative manner

Acyl-coenzyme A:cholesterol acyltransferase (ACAT) is an integral membrane protein located in the endoplasmic reticulum. It catalyzes the formation of cholesteryl esters from cholesterol and long-chain fatty acyl coenzyme A. The first gene encoding the enzyme, designated as ACAT-1, was identified in 1993 through an expression cloning approach. We isolated a Chinese hamster ovary cell line that stably expresses the recombinant human ACAT-1 protein bearing an N-terminal hexahistidine tag. We purified this enzyme approximately 7000-fold from crude cell extracts by first solubilizing the cell membranes with the zwitterionic detergent 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate, then proceeding with an ACAT-1 monoclonal antibody affinity column and an immobilized metal affinity column. The final preparation is enzymologically active and migrates as a single band at 54 kDa on SDS-polyacrylamide gel electrophoresis. Pure ACAT-1 dispersed in mixed micelles containing sodium taurocholate, phosphatidylcholine, and cholesterol remains catalytically active. The cholesterol substrate saturation curves of the enzyme assayed either in mixed micelles or in reconstituted vesicles are both highly sigmoidal. The oleoyl-coenzyme A substrate saturation curves of the enzyme assayed under the same conditions are both hyperbolic. These results support the hypothesis that ACAT is an allosteric enzyme regulated by cholesterol.

Seasonal variation of chickenpox, mumps and rubella in Taiwanese children estimated by pediatric clinics

To determine the seasonal variation of childhood infectious diseases in Taiwan, the incidence rates of chickenpox, mumps and rubella were studied by analyzing patient's records collected from pediatric clinics in northern, central, southern and eastern Taiwan from January 1, 1993 to December 31, 1993. The study revealed that a chickenpox outbreak was most likely to occur in autumn, followed by a second peak in spring, and the lowest rate in summer. In this study, the highest monthly incidence of chickenpox was 540 cases per 100,000 population. The highest incidence of mumps occurred in the spring, the second highest in autumn, and the lowest during summer. Cases of rubella occurred in the spring, summer and autumn, but not in the winter. The data on chickenpox from this study revealed a similar seasonal pattern every year to that of the Department of Health of the National Quarantine Service on Taiwan. The chickenpox virus is known to be relatively sensitive to elevations in ambient temperature and is characterized by its occurrence mainly in slightly humid seasons.

Synthesis and cytotoxicity of 2-acetyl-4,8-dihydrobenzodithiophene-4, 8-dione derivatives

2-Acetyl-4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-dione (9) and 2-acetyl-4,8-dihydrobenzo[1,2-b:5,4-b']dithiophene-4,8-dione (19), together with 10 related mono- and disubstituted derivatives, were synthesized and evaluated in vitro by NCI against eight cancer types. All compounds showed significant activity against melanoma, HL-60 leukemia, NCI-H23 non-small-cell lung cancer, OVCAR-3 ovarian cancer, and MDA-MB-435 and MDA-N breast cancer cell lines. Compound 11, 2-(1'-acetoxyethyl)-4,8-dihydrobenzo[1,2-b:4,5-b']dithiophene-4, 8-dione, showed the highest overall potency (mean GI50 = 40 nM).

Trichloroethylene biodegradation by phenoloxidizing cultures grown from various conditions

The rate and extent of trichloroethylene (TCE) degradation by three cultures of phenol oxidizing bacteria grown from two chemostats and one from rotating biological contactors was investigated. Batch experiments were performed to measure the disappearance of TCE both with the resting cell alone and with the formate added. Experimental data were then compared with mathematical predictions from a model describing TCE transformation. Through nonlinear regression analysis, a best fit between the measurements and predictions was achieved when residual sum of squares reached a minimum. Based on the resultant parameters of transformation capacity and reaction rate, the suspended cells with a mean cell retention time (MCRT) of 3.8 days were the most active in degrading TCE, while the attached bacteria had the least activity. Based on the results presented herein, it is recommend that using suspended-growth reactors operated at short MCRT to produce desirable cells for cometablic transformation of TCE.

Health status of urban and rural elders in Korea

The main purpose of this study was to describe the differences in health status between urban and rural elders in Korea. The sample consisted of one thousand one hundred non-institutionalized individuals, aged 65 or over, living in three metropolitan cities and two rural provinces. The modified Cornell Medical Index, ADL, IADL, and existing medical diagnosis were used to measure the health status of the elders. Rural elders reported significantly more health problems than urban elders. Differences in ADL and IADL scores were not statistically significant. There was a difference in the types of health problems between the urban and rural elders. While more rural elders reported that they were diagnosed as having neuralgia and arthritis, more urban elders reported that they had diabetes. The results of this study demonstrated that rural elders had significantly more health problems than urban elders even after all the other variables were controlled. However, in Korea, most health care resources available to elders are concentrated in large urban cities. This study suggests that it is important to invest more health care resources in rural areas to meet the needs of all elders in Korea.

Comparison of once daily cefpodoxime proxetil suspension and thrice daily cefaclor suspension in the treatment of acute otitis media in children

An open-labeled and randomized trial was conducted to compare the efficacy and safety of once daily cefpodoxime proxetil suspension (10mg/kg/day) and thrice daily cefaclor (45mg/kg/day) in the treatment of acute otitis media in children. A total of 57 children aged from 6 months to 9 years were enrolled; 23 were treated with cefpodoxime and 34 with cefaclor. Satisfactory clinical outcome, either cure or improvement, was achieved at the end of treatment in 90% of patients in the cefaclor group and 95% of patients in the cefpodoxime group (p > 0.05). Clinical recurrence was identified at the follow-up visits in one case of the cefaclor group (3%), and none in the cefpodoxime group (p > 0.05). These drugs were well tolerated by 14/21 (67%) in the cefpodoxime-treated group and 27/32 (84%) in the cefaclor-treated group. The incidence of adverse events was slightly higher in the cefpodoxime group than in the cefaclor group, however the difference did not reach statistical significance (p > 0.05). The daily cost of once-daily cefpodoxime was lower than that of thrice-daily cefaclor. We conclude that cefpodoxime administered once daily is as effective and safe as cefaclor administered thrice daily in the treatment of acute otitis media in children. The less dosing frequency and lower daily price of cefpodoxime provide additional benefits.

Immunogenicity and safety of Haemophilus influenzae type b conjugate vaccine (HibTITER) and a combination vaccine of diphtheria, tetanus, pertussis and HibTITER (TETRAMUNE) in two-month-old infants

A study was undertaken to evaluate the safety and immunogenicity of a combination vaccine (TETRAMUNE) of conjugate Haemophilus influenzae type b (Hib) vaccine (HibTITER) and DTP (Diphtheria, Tetanus and Pertussis) vaccine. A total of 93 healthy children were randomized to receive either TETRAMUNE (combined group), or DTP and HibTITER administered concurrently (separate group) in separate syringes at approximately 2, 4 and 6 months of age in Taiwan. Serologic responses were largely comparable between the two vaccine groups; almost all subjects were seropositive to Hib PRP (polyribosylribitol phosphate) and were protected against diphtheria and tetanus after 2 doses of vaccine and mounted prominent responses to the components of Bordetella pertussis. Subjects in the combined group did not experience more adverse reactions compared with those in the separate group. We concluded that HibTITER was highly immunogenic and safe when administered concurrently with DTP vaccine to Taiwanese children. TETRAMUNE was also safe and immunogenic and might reduce the number of injections to achieve the same protection.

Chromosomal mapping, tissue distribution and cDNA sequence of four-and-a-half LIM domain protein 1 (FHL1)

We have isolated and sequenced a human heart cDNA clone encoding a novel LIM-only protein. This full-length cDNA clone has a predicted open reading frame (ORF) encoding 280 amino acids. The ORF of this cDNA codes for a LIM-only protein that possesses four repeats of LIM domain and an extra zinc finger and this putative protein is named four-and-a-half LIM domain protein 1 (FHL1). FHL1 is unique when compared with other LIM-only proteins because it possesses an odd number of zinc fingers. When the FHL1 cDNA probe was used to hybridize with poly-(A) RNA of various human tissues, a very strong signal was detected in skeletal muscle, a moderate one in the heart; only weak signals were associated with the placenta, ovary, prostate, testis, small intestine, colon and spleen, and virtually no signal could be detected in brain, lung, liver, kidney, pancreas, thymus and peripheral blood leukocytes. The FHL1 gene was located to human chromosome at Xq27.2 by somatic cell hybrid mapping, fluorescent in situ hybridization (FISH) and radiation hybrid mapping.

The rise of nuclear and cytosolic Ca2+ can be uncoupled in HeLa cells

It has long been assumed that ionized Ca2+ is transmitted from the cytosol to the cell nucleus through the nuclear pore complexes to trigger many nuclear functions such as gene transcription after agonist stimulation. However, this hypothesis has been challenged recently. In the present study, we have investigated the interplay of Ca2+ in the cytosol and nucleus of HeLa cells upon histamine stimulation by using confocal microscopy. In resting cells, addition of histamine (50 microM) produced synchronous Ca2+ signals in the cytosol and nucleus with a stronger fluo-3 emission in the nucleus. Our results also demonstrate that the rise of cytosolic and nuclear free Ca2+ can be uncoupled after histamine stimulation. This assertion is supported by the following observations: (1) when heparin was injected into the cytosol, the increase in fluo-3 fluorescence in the cytosol mediated by histamine was almost eliminated while that in the nucleus still occurred; (2) when heparin was in the nucleus, the increase in the free nucleoplasmic Ca2+ concentration ([Ca2+]n) elicited by histamine was abolished while the rise of cytosolic Ca2+ level ([Ca2+]c) was seen; (3) when we injected inositol 1,4,5-trisphosphate (IP3) directly into the nucleus, [Ca2+]n increased; and (4) in the cells given cytosolic injections of BAPTA-dextran (70 kDa), histamine evoked additional Ca2+ transients in the nucleus. These results suggest that the nucleus of the HeLa cell has its own IP3-sensitive Ca2+ store and that the Ca2+ signals in the nucleus and cytosol can be uncoupled.

Ca2+ is released from the nuclear tubular structure into nucleoplasm in C6 glioma cells after stimulation with phorbol ester

It is well established that cellular Ca2+ is an important messenger that controls many nuclear functions but the source of nuclear Ca2+ is far from clear. It has long been thought that Ca2+ is translocated from the cytosol over a long distance to activate the nuclear transcription machinery. However, this model is at best an incomplete one. With the aid of confocal microscopy, we observed tubules extended deep inside the nucleus of C6 cells in agreement with previous studies (Fricker et al. (1997) J. Cell Biol. 136, 531-544). When cells were stimulated with phorbol 12-myristate 13-acetate or phorbol 12,13-diacetate, Ca2+ was released from these tubules. DiOC6(3), a vital marker for intracellular membranes, stained the tubule in the nucleus of the same cell used for Ca2+ imaging. Moreover, results from labelling the cells with rhodamine 123 further indicate that the tubule was formed by a double-membraned invagination with mitochondria inside. Studies with acridine orange showed that chromatin was excluded from the tubules. Taken together, our results demonstrate that the nuclear tubule is a structural entity responsible for the release of Ca2+ into the nucleoplasm after stimulation with phorbol ester.

Factors affecting the collagen binding capacity of Staphylococcus aureus

To determine whether the ability of Staphylococcus aureus to bind collagen involves an adhesin other than the collagen adhesin encoded by cna, we examined the collagen binding capacity (CBC) of 32 strains of S. aureus. With only two exceptions, a high CBC corresponded with the presence of cna. Both exceptions involved cna-positive strains with a low CBC. The first was a single strain (ACH5) that encoded but did not express cna. The second were the mucoid strains Smith diffuse and M, both of which encoded and expressed cna but bound only minimal amounts of collagen. Analysis of capsule mutants suggests that the reduced CBC observed in the mucoid strains was due to masking of the collagen adhesin on the cell surface and that this masking effect is restricted to heavily encapsulated strains. Differences in the CBC of the remaining cna-positive strains were correlated to variations in the level of cna transcription and were independent of the number of B domain repeats in the cna gene. In all cna-positive strains other than ACH5, cna transcription was temporally regulated, with cna mRNA levels being highest in cells taken from exponentially growing cultures and falling to almost undetectable levels as cultures entered the post-exponential growth phase. The CBC was also highest with cells taken from exponentially growing cultures. Mutation of agr resulted in a slight increase in cna transcription and a corresponding increase in CBC during the exponential growth phase but did not affect the temporal pattern of cna transcription. Mutation of sar resulted in a more dramatic increase in CBC and a delay in the post-exponential-phase repression of cna transcription. Mutation of both sar and agr had an additive effect on both CBC and cna transcription. We conclude that (i) cna encodes the primary collagen-binding adhesin in S. aureus, (ii) sar is the primary regulatory element controlling expression of cna, and (iii) the regulatory effects of sar and agr on cna transcription are independent of the interaction between sar and agr.

Susceptibility of heterozygous MnSOD gene-knockout mice to oxygen toxicity

Recent studies have shown that homozygous Mn superoxide dismutase (Sod2) gene-knockout mice (Sod2(-/-)) die shortly after birth with extensive myocardial injury, whereas heterozygous mutants (Sod2(+/-)) are phenotypically normal in room air. In the current study, we showed that Sod2(+/-) mice with approximately 50% of normal pulmonary MnSOD activity and normal levels of lung CuZnSOD, catalase, and glutathione peroxidase activities were not substantially more susceptible to 100% O2 toxicity than their normal Sod2(+/+) littermates. The mean (+/- SD) survival of Sod2(+/-) mice in 100% O2 was 101.4 +/- 14.8 h (n = 20) versus 103.2 +/- 11.3 h (n = 20) for Sod2(+/+) littermates (P > 0.60). In addition, Sod2(+/-) mice with approximately 50% of normal heart MnSOD activity and Sod2(+/+) mice did not develop any ultrastructural abnormalities in the myocardium at 75 h or 90 h after 100% O2 exposure. These results suggest that in mice, only 50% of MnSOD activity may be sufficient for normal resistance to 100% O2 toxicity.

The nucleus of HeLa cell contains tubular structures for Ca2+ signalling

It has long been assumed that Ca2+ are translocated from the cytosol to the cell nucleus by a long distance to activate transcription machinery buried deep in the nucleoplasm. However, this model has been recently challenged. When HeLa cells were loaded with fluo-3, highly fluorescent spots of approximately 2 microns in diameter were observed in the cell nucleus while the fluo-3 signals were low in their neighbouring nucleoplasm as determined by confocal microscopy. These fluorescent spots were devoid of but usually associated with chromatin on their boundary. When cells were stimulated by ionomycin (1 microM), the fluo-3 fluorescence in these spots increased faster than that in their neighbouring nucleoplasm. In another experiment, optical sections with hot spot(s) were used to construct 3-D images to study the morphology of the hot spots. Views of reconstruction from different angles indicated that the hot spots formed a tubular structure with a connection to the nucleocytoplasmic interface. Moreover, injection of calcium green-dextran (70 kDa), a Ca(2+)-sensitive indicator conjugated with an inert molecule of large molecular size, into the cytosol leads to a formation of signals also in a tubular shape inside the nucleoplasm. This suggests that the 'channels' are real inside the nucleus and they are derived from an invagination of the double-membraned nuclear envelope. Taken together, our results indicate (1) tubular structures are found inside the cell nucleus; (2) they are extended from the cytosol into the nucleus through the invagination of the double membraned nuclear envelope; (3) molecules of molecular size up to 70 kDa could penetrate into these 'tunnels'; (4) Ca2+ can be released or transported into the cell nucleus through these tubular structures after ionomycin stimulation; and (5) the structures are usually associated with chromatin.

Bacteremia and fungemia in hematological and oncological children with neutropenic fever: two-year study in a medical center

A retrospective study of bacteremia in children with neutropenic fever admitted to a medical center in Taiwan from Jan. 1994 to Dec. 1995 was performed. There were in total 273 episodes of neutropenic fever during this period, but only 79 pathogens were isolated from blood specimens in 70 episodes. Klebsiella pneumoniae (27.8%), E. coli (10.1%), Staphylococcus aureus (10.1%) and Pseudomonas aeruginosa (7.6%) were the most common pathogens. All the isolates of S. aureus were methicillin sensitive. About half of K. pneumoniae (10/22) was multiple-drug resistant. There were seven infection-related mortality cases, three due to multiple-drug resistant K. pneumoniae, one due to S. aureus, one alpha-hemolytic streptococcus and two fungemia (Cryptococcus neoformans and Fusarium sp.). Vancomycin is not necessary in initial empiric therapy of neutropenic fever, while cefazolin or oxacillin may be included in cases with central venous access device. Antibiotics to cover intestinal flora, especially K. pneumoniae, are paramount in our hospital.