Mapping of the Cryptococcus neoformans MATalpha locus: presence of mating type-specific mitogen-activated protein kinase cascade homologs

In this study we investigated the relationship between the MATalpha locus of Cryptococcus neoformans and several MATalpha-specific mitogen-activated protein (MAP) kinase signal transduction cascade genes, including STE12alpha, STE11alpha, and STE20alpha. To resolve the location of the genes, we screened a cosmid library of the MATalpha strain B-4500 (JEC21), which was chosen for the C. neoformans genome project. We isolated several overlapping cosmids spanning a region of about 71 kb covering the entire MATalpha locus. It was found that STE12alpha, STE11alpha, and STE20alpha are imbedded within the locus rather than closely linked to the locus. Furthermore, three copies of MFalpha, the mating type alpha-pheromone gene, a MATalpha-specific myosin gene, and a pheromone receptor (CPRalpha) were identified within the locus. We created a physical map, based on the restriction enzyme BamHI, and identified both borders of the MATalpha locus. The MATalpha locus of C. neoformans is approximately 50 kb in size and is one of the largest mating type loci reported among fungi with a one-locus, two-allele mating system.

Hepatofugal flow on computed tomography of arterial portography: its correlation with esophageal varices bleeding

BACKGROUND/AIMS

To study the portal flow patterns from CTAP (computed tomography of arterial portography), then to predict the existence of esophageal varices bleeding clinically.

METHODOLOGY

192 patients who underwent CTAP from superior mesenteric artery infusion were recruited in this study. The obtained images were classified according to our proposed criteria. Stage 0: hepatopetal flow, when all the contrast medium from the superior mesenteric vein entered the portal vein. Stage 1: when the contrast medium opacified the splenic vein or the other collateral vessels. Stage II: when the contrast medium opacified the paraesophageal vessels without entering the inner wall of the esophagus. Stage III: when the contrast medium opacified the collaterals up to the inner wall of the esophagus.

RESULTS

The incidence of bleeding esophageal varices was correlated to the different stages of collateral flows pattern obtained. The esophageal varices bleeding rates were 0/137, 1/16, 1/14, 16/25 for stage 0, I, II and III, respectively. The incidence of bleeding esophageal varices was significantly higher in stage III group than in the other groups (P < 0.001). The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of stage III patients in regard to the occurrence of bleeding esophageal varices were estimated as 80.0%, 98.8%, 88.9%, 94.8%, and 94.3%, respectively.

CONCLUSIONS

Our results show that CTAP demonstrates the portal flow patterns and collateral veins clearly, which can serve as an excellent imaging modality to predict the risk of esophageal varices bleeding.

Caspase-dependent apoptosis by ectopic expression of E2F-4

E2F is a family of transcription factors which regulates cell cycle and apoptosis of mammalian cells. E2F-1-3 localize in the nucleus, and preferentially bind pRb, while E2F-4 and 5 have no nuclear localization signal and preferentially bind p107/p130. E2F-6 suppresses the transcriptional activity of other E2F proteins. DP-1 and 2 are heterodimeric partners of each E2F protein. Using tetracycline-responsive promoters, here we compared the effects of ectopic expression of E2F-1, DP-1 and E2F-4 on cell cycle progression and apoptosis in Chinese hamster cell lines. We found that E2F-4, as well as DP-1 and E2F-1, induced growth arrest and caspase-dependent apoptosis. E2F-4 did not have a marked effect on cell cycle progression, while E2F-1 induced DNA synthesis of resting cells and DP-1 arrested cells in G1. Ectopic expression of E2F-4 did not activate E2F-dependent transcription. Our results suggest that expression of E2F-4 at elevated levels induces growth arrest and apoptosis of mammalian cells through a mechanism distinct from E2F-1 and DP-1.

Growth enhancement of fowls by dietary administration of recombinant yeast cultures containing enriched growth hormone

In present study the methylotrophic yeast, Pichia pastoris, was used to express a recombinant growth hormone (rGH) gene of swine. A synthetic secretion cassette was constructed using the promoter of the alcohol oxidase1 gene (AOX1), and a alpha-factor signal peptide. After electroporatic transformation and zeocin selection, several clones exhibited high levels of rGH protein expression constituting more than 20% of total yeast protein. Over 95% of rGH was shown to be export into the culture supernatant. Yeast transformant containing the highest recombinant growth hormone level (rGH yeast) and native GS115 Pichia pastoris (non-rGH yeast, as a control) were separately cultured, harvested and adsorbed by wheat bran. Yeast cultures of four dosages (0.05, 0.1, 0.2, and 0.4%) were mixed respectively with chick basal diet and fed to simulated country chickens for 9 weeks. The results showed that, when compared to control chicks, the percentage of body weight gain was improved significantly (P<0.05) in chicks fed with diets containing 0.1 or 0.2% rGH-rich yeast culture at brooding stage, and in chicks fed with 0.4% rGH-rich yeast culture at growing stage. The average weight gain in rGH yeast treated groups for the full-term (0 to 63d) and short term (43 to 63d) of growth were 10.6 and 9.4%, respectively, better than the non-rGH yeast control group. These experimental data suggest that the use of rGH-containing yeast as a supplement in fed provided an alternative approach for growth improvement in simulated country chickens.

Endometrial stromal sarcoma of the vagina

Endometrial stromal sarcoma is a rare tumor and has unique histopathologic features. Most tumors of this kind occur in the uterus; thus, the vagina is an extremely rare site. A 34-year-old woman presented with endometrial stromal sarcoma arising in the vagina. No correlative endometriosis was found. Because of the uncommon location, this tumor was differentiated from other more common neoplasms of the vagina, particularly embryonal rhabdomyosarcoma and other smooth muscle tumors. Although the pathogenesis of endometrial stromal tumors remains controversial, the most common theory of its origin is heterotopic Müllerian tissue such as endometriosis tissue. Primitive cells of the pelvis and retroperitoneum are an alternative possible origin for the tumor if endometriosis is not present. According to the literature, the tumor has a fairly good prognosis compared with other vaginal sarcomas. Surgery combined with adjuvant radiotherapy appears to be an adequate treatment.

Properties of various Rho1 mutant alleles of Cryptococcus neoformans

The RHO1 homologue of Cryptococcus neoformans complemented Saccharomyces cerevisiae rho1 mutations. The results of overexpression and site-specific mutagenesis of CnRHO1 in C. neoformans and S. cerevisiae indicated that although CnRHO1 could functionally substitute for the RHO1 gene of S. cerevisiae, mutants of cnrho1 manifested unique features in certain aspects.

Expression of Bcl-2 inhibited Fas-mediated apoptosis in human hepatocellular carcinoma BEL-7404 cells

Apoptosis plays an important role in embryonic development, tissue remodeling, immune regulation and tumor regression. Two groups of molecules (Bcl-2 family and "Death factor" family) are involved in regulating apoptosis. In order to know about the effect of Bcl-2 on apoptosis induced by Fas, a typical member of "Death factor" family, the transfection experiments with expression vectors pcDNA3-fl and pcDNA3-bcl-2 were performed in BEL-7404 cells, a human hepatocellular carcinoma cell line which expresses endogenous Fas, but not FasL and Bcl-2. The data showed that the expression of FasL in pcDNA3-fl transfected hepatoma cells obviously induced the apoptosis of the cells. However, the overexpression of Bcl-2 in pcDNA3-bcl-2 transfected 7404/b-16 cells counteracted pcDNA3-fl transient transfection mediated apoptosis. Further study by co-transfection experiments indicated that Bid but not Bax (both were pro-apoptotic proteins of Bcl-2 family) blocked the inhibitory effect of Bcl-2 on Fas-mediated apoptosis. These results suggested that Fas-mediated apoptosis in human hepatoma cells is possibly regulated by Bcl-2 family proteins via mitochondria pathway.

Effects of disulfide bonds formed during isolation process on the structure of the postsynaptic density

The biochemical, morphological and structural properties of rat postsynaptic densities (PSDs) isolated under conditions where disulfide bond formation was allowed or curtailed were studied here. Biochemical analyses revealed that the isolated PSDs were composed by a similar set of proteins regardless of the differences in their isolation processes. The PSDs isolated under the conditions where disulfide bond formation was curtailed were more easily dissociated by treatments with urea, guanidine hydrochloride and deoxycholate than the PSDs isolated under conditions where disulfide bond formation was allowed. Consistently, the structure of the PSDs isolated under the former condition appeared to be more fragmented than those isolated under the latter condition, as revealed by electron microscopy. The results indicate that the disulfide bonds formed during the isolation process significantly tighten the PSD structure and further suggest that the PSD in vivo is a protein aggregate whose constituent proteins be held together primarily by non-covalent interactions.

Cytotoxic and nongenotoxic effects of phenolic compounds in human pulp cell cultures

Phenolic compounds are widely used in clinical dentistry as sedatives for the dental pulp, as disinfectants for caries, and as root canal medications. The pathobiological effects of various phenolic compounds on human dental pulp fibroblasts were investigated with Hoechst 33258 fluorescence assay and DNA precipitation assay. All phenolic compounds showed cytotoxicity in Hoechst 33258 fluorescence assay by inhibiting cellular DNA in a concentration-dependent manner. The 50% inhibition concentrations required to decrease the cellular DNA contents by guaiacol, phenol, eugenol, and thymol were 9.8, 4.5, 0.9, and 0.5 mM, respectively. However these phenolic compounds did not cause DNA single-strand breaks in cultured human pulp fibroblasts. These results indicate that phenolic compounds are cytotoxic agents but are without genotoxic effects on human pulp fibroblasts in vitro. However care should be taken to reduce the possibility of pulpal as well as periapical irritations from inadvertent extrusion of these substances in clinical usage.

Cytotoxicity evaluation of perforation repair materials on human periodontal ligament cells in vitro

Perforation of a tooth structure resulting in communication of the pulp space with periodontium occasionally occurs during endodontic therapy. For the best prognosis, the perforation area must be sealed as soon as possible. Because these materials will be in direct contact with periodontal tissues, their cytotoxic potential must be evaluated before clinical use. The purpose of this study was to determine the cytocompatibility of three perforation repair materials (amalgam, resin, and glass ionomer). Cultured human periodontal ligament (PDL) cells were used to evaluate the cellular response resulting from these materials by cell viability and proliferation assays. Twenty-seven 5 x 4 mm cylinders of each material were fabricated for this study. All tested materials were cytotoxic to human PDL cells. Both types of material and time affected cell viability and proliferation. Resin exhibited the most cytotoxic effects followed by glass ionomer and amalgam during a 14-day incubation period. Amalgam and glass ionomer slightly inhibited cell viability and growth in the first 24 hr, compared with the control. Amalgam or glass ionomer may initially react more favorably to PDL cells than resin. The present model of cultured human PDL cells is simple, relatively cheap, and easily established and propagated under standardized conditions in any laboratory. Furthermore, this method allows long-term observation of human cellular reactions and thus might be a preliminary screening test for initial biocompatibility of dental materials.

Striatal glutamate release during novelty exposure-induced hyperactivity in olfactory bulbectomized rats

Striatal glutamate release during novelty exposure-induced hyperactivity was studied by microdialysis in freely-moving olfactory bulbectomized (OBX) rats. After collecting three 10 min basal striatal dialysate samples, the animals were transferred to an open-field apparatus (novelty) and locomotor activity recorded for 60 min. OBX rats showed significantly more locomotor activity (1210+/-270 cm) than sham-operated rats (420+/-70 cm), but only in the first 10 min after exposure to the novel environment. During the same period, striatal glutamate levels increased to 163+/-21% of the basal value in OBX rats, while no changes were seen in the striatum of sham-operated controls. These findings suggest that olfactory bulbectomy results in an increased response of the striatal glutamatergic system to novelty stress, and may consequently cause hyperactivity.

Comparison of skeletal muscle microcirculation between clamp ischemia and microsurgical ischemia

We compared ischemia reperfusion injury-associated vasospasm and perfused capillary density (PCD) at the microcirculatory level between clamp ischemia and microsurgical ischemia in rat skeletal muscle. Rat cremaster muscle was prepared as an island flap, attached only with pudic-epigastric vessels branching from external iliac vessels. Two types of ischemia, with clamping only or with microvascular anastomosis, were applied at the external iliac vessels for 2 hours followed by 1-hour reperfusion before in vivo microscopic examination for hemodynamic changes. At the end of observation, small segments of the vessels at the clamping site and microsurgical anastomoses site were also harvested for histological examination. It was found that the first- and second-order arterioles had about 12-15% diameter reductions in both groups, whereas diameter reductions of the third-order arterioles were up to 37.8% in the microsurgical ischemia group, much greater than that in the clamp ischemia group (2.3%). There was also no significant difference in PCD reduction between the two groups, although the red blood cell velocity was much slower in the microsurgical ischemia group. Histological examination of the anastomosis site showed massive accumulation of polymorphonuclear neutrophils on the venous endothelium. These results suggested a different degree of endothelial damage and local leukocyte activation between microsurgical ischemia and clamp ischemia. Therefore, we conclude that clamp ischemia cannot replace microsurgical ischemia for studying microcirculatory changes in free tissue transfer.

Prospective study of the outcomes of ambulatory patients with excessive warfarin anticoagulation

BACKGROUND

Warfarin sodium therapy is highly effective in preventing thromboembolism. Its major toxic effect is hemorrhage, the risk of which increases with the international normalized ratio (INR). Data on the rate of major hemorrhage and the rate of INR decay after an episode of excessive anticoagulation therapy would help guide management of elevated INRs in the outpatient setting.

METHODS

We prospectively followed up outpatients in an anticoagulant therapy unit from April 24, 1995, through March 1, 1996. Study patients had to be taking warfarin for longer than 1 month and have an INR target range of 2.0 to 3.0. Consecutive outpatients with an INR greater than 6.0 were identified and compared with a randomly selected concurrent set of patients whose INR was in the target range. Major hemorrhage was defined as fatal, intracranial, or requiring hospitalization and transfusion of at least 2 U of blood.

RESULTS

One hundred fourteen patients with INRs greater than 6.0 were identified and compared with 268 patients with INRs in the target range. None of the patients had clinically apparent bleeding at the time of the INR measurement, and none received phytonadione (vitamin K1). Patients did not differ significantly in age, sex, indication, or duration of warfarin therapy. Ten patients with an INR greater than 6.0 (8.8%; 95% confidence interval, 4.3%-15.5%) sought medical attention for abnormal bleeding, and 5 of these experienced a major hemorrhage during 14-day follow-up (4.4%; 95% confidence interval, 1.4%-9.9%) compared with none of the patients with an in-range INR (P<.001). Thirty-three percent of patients with INRs greater than 6.0 had INRs less than 4.0 within 24 hours, 55% within 48 hours, 73% within 72 hours, and nearly 90% within 96 hours of temporary discontinuation of warfarin therapy.

CONCLUSIONS

Outpatients with INRs greater than 6.0 face a significant short-term risk of major hemorrhage. Randomized trials are needed to determine the net benefit of preventive treatment with phytonadione.

New alkaloids from Annona purpurea

Three new alkaloids, promucosine (1), romucosine F (2), and romucosine G (3), along with 28 known compounds, were isolated from the MeOH extract of stems of Annona purpurea. The structures of 1-3 were determined on the basis of spectral data and chemical evidence.

Carbon urea breath test is not as accurate as endoscopy to detect Helicobacter pylori after gastrectomy

BACKGROUND

This study was conducted to determine (1) whether Helicobacter pylori infection decreases in conjunction with time elapsed after gastrectomy and (2) the diagnostic efficacy of (13)C urea breath test (UBT) for H pylori in patients after gastrectomy.

METHODS

From January 1997 to June 1998, 86 patients who had undergone gastrectomy and 180 patients with dyspepsia without gastrectomy were enrolled. A UBT for the analysis of excess (13)CO(2)/(12)CO(2) ratio (ECR) was obtained for each patient. Each patient also underwent endoscopy to obtain gastric biopsies for histology and H pylori culture. The presence of H pylori by either histology or culture served as the standard to test the efficacy of UBT. The 86 patients with a prior gastrectomy were categorized into 3 subgroups (I, less than 1 year; II, 1 to 3 years; III, greater than 3 years), according to the interval between surgery and UBT. The initial H pylori status of these 86 patients was determined by histologic evaluation of the resected stomach.

RESULTS

At trial initiation, the postgastrectomy group had a lower H pylori infection rate (52.3%) as compared with the dyspeptic control group (80%). The initial H pylori status among subgroups I, II, and III was similar. There was a trend for the presence of H pylori in the stomach to decrease with increasing time elapsed after surgery (I to III: 68.8%, 48.3%, 36%, respectively; p < 0.05). The maximum UBT sensitivity and specificity achieved were 82.2% and 87.8% in the gastrectomy group and 97.2% and 96.3% in the dyspeptic group, with cutoff points of 2.5 and 4.0, respectively.

CONCLUSION

The prevalence of H pylori diminishes with time elapsed after gastrectomy. UBT for detection of H pylori is more effective in patients without prior gastrectomy than in patients who have undergone gastrectomy and is less effective than endoscopy for patients who have had a gastrectomy.

A novel episomal shuttle vector for transformation of Cryptococcus neoformans with the ccdB gene as a positive selection marker in bacteria

We report the engineering of a new shuttle vector featuring its episomal maintenance in Cryptococcus neoformans and the lethal Escherichia coli ccdB gene for positive selection in bacteria. Telomere-like sequences from C. neoformans and the STAB fragment confer episomal maintenance to the vector (pPM8) upon transformation in C. neoformans. The vector generated high transformation frequencies and each transformant was estimated to harbor thirty copies of the plasmid. The plasmids recovered in E. coli from the C. neoformans transformants showed no evidence of rearrangement. This construct will be very useful for cloning and studying the regulation of genes in C. neoformans.

Residuals analysis of the generalized linear models for longitudinal data

The generalized estimation equation (GEE) method, one of the generalized linear models for longitudinal data, has been used widely in medical research. However, the related sensitivity analysis problem has not been explored intensively. One of the possible reasons for this was due to the correlated structure within the same subject. We showed that the conventional residuals plots for model diagnosis in longitudinal data could mislead a researcher into trusting the fitted model. A non-parametric method, named the Wald-Wolfowitz run test, was proposed to check the residuals plots both quantitatively and graphically. The rationale proposedin this paper is well illustrated with two real clinical studies in Taiwan.

Comprehensive cloning and expression analysis of glycolytic genes from the filamentous fungus, Aspergillus oryzae

We cloned all the glycolytic genes from Aspergillus oryzae and analyzed their transcriptional regulation by the carbon source in the medium. The deduced amino-acid sequences of the glycolytic genes showed high identity (approximately 41-93%) to those from other lower eukaryotes. Genomic Southern hybridization indicated that all the genes existed as a single copy in the genome. Comparison of mRNA levels between mycelia grown on glucose and on pyruvate showed that most of the A. oryzae glycolytic genes were induced by glucose in the medium. The overall expression profiles of the A. oryzae glycolytic genes resembled those of Saccharomyces cerevisiae. The expression of one of the phosphofructokinase genes (pfkB), however, was repressed by glucose while both PFK1 and PFK2 were induced in S. cerevisiae. These findings indicate that further analysis of the transcriptional regulation of the A. oryzae glycolytic genes will be useful for investigating the evolutionary change of transcription regulation in lower eukaryotes and to construct promoters for industrial applications.

Mutation of p53 gene codon 63 in saliva as a molecular marker for oral squamous cell carcinomas

The inactivation of tumor suppressor gene (TSG) is important during multistage carcinogenesis. The p53 TSG is frequently mutated in oral squamous cell carcinomas. These mutations can serve as very specific markers for the presence of tumor cells in a background of normal cells. In this study, 10 oral squamous cell carcinoma patients and 27 normal dental students were collected from Chung Shan Medical and Dental College Hospital, Taichung, Taiwan. Extractions of DNA from saliva were obtained. Exon 4 and intron 6 within the p53 gene were amplified with polymerase chain reactions (PCRs) followed by DNA sequence analysis. DNA sequence analysis of PCR products revealed that five of eight (62.5%) tumor saliva samples and five of 27 (18. 52%) healthy saliva samples contained p53 exon 4 codon 63 mutations. These results were significantly different by using Chi-square test (P<0.05). The majority of the base substitutions were C deletions. Probable hot spots for the mutation were identified at exon 4 codon 63, which has not been observed before in head and neck cancers. Our study indicated that mutation of p53 codon 63 in saliva might be a molecular marker for oral squamous cell carcinomas. In addition, the amount of DNA recovered from saliva in most cases is sufficiently large and its quality suitable to enable PCR amplification which could be used in the search for mutations. The protocol described is rapid, cheap, and easy to perform, and may be useful for epidemiological studies for oral carcinogenesis.

Identification of a pre-S2 mutant in hepatocytes expressing a novel marginal pattern of surface antigen in advanced diseases of chronic hepatitis B virus infection

BACKGROUND AND AIMS

The expression of hepatitis B viral (HBV) antigens in liver tissue reflects the replicative status of chronic HBV infection. We have previously recognized a novel marginal pattern of hepatitis B surface antigen (HBsAg) in hepatocytes, which usually clusters in groups and emerges at the late non-replicative phase. This study was designed to investigate whether the marginal-type HBsAg represented the gene product of a specific HBV-surface mutant.

METHODS

Microdissection of cirrhotic nodules homogeneously expressing marginal HBsAg was performed on two of 12 resected livers from HBsAg-seropositive patients with hepatocellular carcinoma. The gene presumably encoding marginal HBsAg was polymerase chain reaction (PCR)-cloned, sequenced and analysed. In vitro transfection and expression of the cloned surface mutant plasmids were performed on the Huh7 cell line to illustrate intrahepatic HBsAg expression.

RESULTS

Immunohistochemical staining revealed that the marginal HBsAg was positive for pre-S1 and thus contained large surface proteins. The PCR cloning and sequencing of the genes presumably encoding marginal-type HBsAg in both cases revealed the same deletion at the 5' terminus (nt 2-55) of pre-S2. A point mutation on the small-surface (S) antigen was also found in one case. The pre-S2 deletion sequence and the mutation sites of the S gene coincide with human lymphocyte antigen-restricted T- and/or B-cell epitopes. In vitro transfection of the mutant plasmid revealed a blot-like retention or accumulation of HBsAg in the cytoplasm or at the periphery of hepatocytes, accompanied by a decreased secretion of HBsAg in the culture supernatant, mimicking intrahepatic expression.

CONCLUSION

A natural pre-S2 deletion mutant was identified in hepatocytes expressing a novel marginal pattern of HBsAg, which probably contains mutant, large, surface proteins. The biological significance of the pre-S2 deletion mutant should be interesting in view of the clustering proliferation of hepatocytes expressing marginal HBsAg.

Neurocognitive attention and behavior outcome of school-age children with a history of febrile convulsions: a population study

PURPOSE

A prospective population-based case-control study was performed to ascertain whether febrile convulsion (FC) in early childhood is associated with neurocognitive attention deficits in school age.

METHODS

A total of 103 children, confirmed to have FC by age 3 years from a population survey of 4,340 live-birth newborns in Tainan City, Taiwan, was followed up until at least age 6 years. An achievement test, behavioral ratings, and computerized neurocognitive battery assessing various subcomponents of attention were given to 87 FC children (FC group) and 87 randomly selected population-matched control (CC group).

RESULTS

Compared with the CC group, the FC group did not have scholastic performance or behavioral outcome disadvantage. Overall FC group performance was distinguished by significantly higher scores in the achievement test and fewer missing errors (p < 0.005) and commission errors (p < 0. 05), less variability in reaction time (p < 0.005), and a nonsignificant trend of impulsivity. Attention performance of the FC and CC groups were comparable. Within the FC group, age at onset, complex FC, recurrence of FC, development of unprovoked seizures, or prior use of phenobarbital had no adverse effects on neurocognitive attention outcome.

CONCLUSIONS

This population study suggests that FC in early childhood does not have adverse effects on behavior, scholastic performance, and neurocognitive attention. On the contrary, the FC group demonstrated significantly better control of distractibility and attention at school age.

Cryptococcus neoformans STE12alpha regulates virulence but is not essential for mating

The Cryptococcus neoformans STE12alpha gene, a homologue of Saccharomyces cerevisiae STE12, exists only in mating type (MAT)alpha cells. In S. cerevisiae, STE12 was required for mating and filament formation. In C. neoformans, haploid fruiting on filament agar required STE12alpha. The ability to form hyphae, however, was not affected by deletion of STE12alpha when convergently growing MATa strains were present. Furthermore, ste12alpha disruptants were fertile when mated with MATa strains, albeit with reduced mating frequency. Most importantly, the virulence of a ste12alpha disruptant of serotype D strain was significantly reduced in a mouse model. When the ste12alpha locus was reconstituted with the wild-type allele by cotransformation, virulence was restored. Histopathological analysis demonstrated a reduction in capsular size of yeast cells, less severe cystic lesions, and stronger immune responses in meninges of mice infected with ste12alpha cells than those of mice infected with STE12alpha cells. Using reporter gene constructs, we found that STE12alpha controls the expression of several phenotypes known to be involved in virulence, such as capsule and melanin production. These results demonstrate a clear molecular link between mating type and virulence in C. neoformans.

Induction of apoptosis in KB cells by pingyangmycin

Pingyangmycin (PYM; Bleomycin A(5)), an antitumour antibiotic is currently used during anticancer therapy. Previous experiments demonstrated that the therapeutic efficiency of PYM for treatment of malignant tumours is considered to be related to its ability to cause DNA strand breaks in vitro. However, very little is known about the interaction of PYM with the target cells, and it is still unclear how PYM enters the cells. In this study, cell death induced by PYM was studied in a human squamous cell carcinoma cell line (KB cells). In order to determine if cell death occurred by necrosis (reproductive cell death) or apoptosis (programmed cell death), KB cells were exposed to different concentrations of PYM and evaluated by biochemical and morphological criteria. Our results indicate that KB cells displayed an arrest in the G(2)-M phase of the cell cycle and became enlarged and polynucleated before dying at the low concentrations of PYM. In contrast, when cells were exposed to high concentrations of PYM, morphological changes identical to those usually associated with apoptosis were observed as well as internucleosomal digestion of genomic DNA. In conclusion, we demonstrate that PYM is able to induce two distinct modes of cell death depending on the doses of PYM.

Swyer-James syndrome complicated by lung abscess

Swyer-James syndrome, a rare disease with unilateral hyperlucent lung due to bronchiolitis obliterans and pulmonary artery hypoplasia, generally develops after lower respiratory tract infection during early childhood. Invasive procedures, including bronchoscopy and angiography, are often necessary for a definitive diagnosis. We report a 17-year-old man admitted because of cystic bronchiectasis complicated by lung abscess. Chest roentgenography showed the typical findings of Swyer-James syndrome. Noninvasive magnetic resonance angiography was used to confirm hypoplasia of the right pulmonary artery. The patient received antibiotic therapy, underwent a right lower lobectomy for the lung abscess, and recovered.

Molecular cloning and characterization of rpbA encoding RNA polymerase II largest subunit from a filamentous fungus, Aspergillus oryzae

We have cloned rpbA encoding the RNA polymerase II largest subunit (polIIL) from a filamentous fungus, Aspergillus oryzae. The rpbA product included eight highly conserved regions and the carboxyl-terminal domain (CTD). A. oryzae polIIL CTD with 184 amino acids was composed of 25 CTD consensus repeats, which was a similar number to those of lower eukaryotes. The amino acids in each repeat of A. oryzae polIIL, however, conformed less to the CTD consensus than those of polIILs from other lower eukaryotes.