Genetic variation of the apolipoprotein B gene in Korean patients with coronary artery disease

In view of the clinical importance of apolipoprotein B (apo B) as a major risk factor for coronary artery disease (CAD), we investigated the two polymorphisms (signal peptide and XbaI) of the apo B gene in 235 Korean patients with CAD and in 216 normal controls. The insertion allele (INS) frequency of signal peptide polymorphism was significantly higher in cases than the controls (P<0.05). Signal peptide polymorphism was also associated with levels of plasma cholesterol, triglyceride and low density lipoprotein-cholesterol. However, XbaI polymorphism was not associated with plasma lipid levels. Therefore, our results suggest that signal peptide polymorphism of the apo B gene might be one of the factors in explaining an association in Korean CAD patients.

SMRT corepressor interacts with PLZF and with the PML-retinoic acid receptor alpha (RARalpha) and PLZF-RARalpha oncoproteins associated with acute promyelocytic leukemia

Retinoic acid receptors (RARs) are hormone-regulated transcription factors that control key aspects of normal differentiation. Aberrant RAR activity may be a causal factor in neoplasia. Human acute promyelocytic leukemia, for example, is tightly linked to chromosomal translocations that fuse novel amino acid sequences (denoted PML, PLZF, and NPM) to the DNA-binding and hormone-binding domains of RARalpha. The resulting chimeric receptors have unique transcriptional properties that may contribute to leukemogenesis. Normal RARs repress gene transcription by associating with ancillary factors denoted corepressors (also referred to as SMRT, N-CoR, TRAC, or RIP13). We report here that the PML-RARalpha and PLZF-RARalpha oncoproteins retain the ability of RARalpha to associate with corepressors, and that this corepressor association correlates with certain aspects of the leukemic phenotype. Unexpectedly, the PLZF moiety itself can interact with SMRT corepressor. This interaction with corepressor is mediated, in part, by a POZ motif within PLZF. Given the presence of POZ motifs in a number of known transcriptional repressors, similar interactions with SMRT may play a role in transcriptional silencing by a variety of both receptor and nonreceptor transcription factors.

Immunocytochemical analysis of peptide hormone processing: importance of the positively charged N-terminal domain of signal peptide in correct ER targeting in yeast cells

We used a morphological approach to determine the topogenic role of the signal peptide in mediating the ER translocation of yeast prepro-alpha-factor. In prepro-alpha-factor-somatostatin hybrids, changes in the N-terminal amino acid sequence from wild-type NH2-Met-Arg-Phe (MRF) to NH2-Met-Phe-Lys (MFK) caused a subtle difference in protein trafficking in yeast cells. Immunofluorescence microscopy on semithin cryosections and immunoelectron microscopy on ultrathin sections showed that the transposition of the charged amino acid at N-terminus caused the precursors to be associated with either nucleus or mitochondria. This suggests that the secretory proteins are mistargeted to the irrelevant organelles as the result of inefficient ER translocation. Structural aspects of nuclear or mitochondrial targeting proteins and common principles in membrane translocation systems account for the mistargeting of overexpressed mutant hybrid precursors that are not rapidly translocated into the ER. Based on our immunocytochemical study on individual cells, we propose here that the positively charged N-terminal domain of signal peptide is important not merely in the efficiency of ER translocation, but also in appropriate targeting of peptide hormone precursors in yeast cells where post-translational ER translocation is known to occur frequently.

Genetic variations of the apo E-CI-CII cluster gene in Koreans

OBJECTIVES

To investigate the allele frequencies of the apolipoprotein (apo) E-CI-CII cluster gene in Koreans, and its relation to plasma lipid and lipoprotein levels.

METHODS

The study subjects consisted of healthy Korean individuals (apo E, 145; apo CI and CII, 81) who were randomly selected via health screening. For polymorphism analysis, DNA was amplified by polymerase chain reaction (PCR). The one-way analysis of variance (ANOVA) test was performed to compare the mean of lipid levels among different genotypes.

RESULTS

The apo E polymorphism in the Korean population appeared as the E4/2, E3/2, E3/3, E4/3, and E4/4 genotypes. The epsilon 3 allele was the most frequent, as in other populations. The apo E polymorphism showed the lack of association with plasma lipid levels in this population. On the other hand, we demonstrated AvaII polymorphism of the apo CII gene by PCR technique. Cholesterol and triglyceride levels were varied significantly among the AvaII genotypes (p < 0.05).

CONCLUSION

No effect of the apo E allele on lipid levels was seen in the Korean population. This result suggests that it might be one of the factors in explaining the low prevalence rate of atherosclerosis in the Korean population. Also, the AvaII polymorphism analysis by PCR is a simple and less time-consuming method.

Type II protein kinase A up-regulation is sufficient to induce growth inhibition in SK-N-SH human neuroblastoma cells

We have previously reported that overexpression of RII beta subunit of protein kinase A, which markedly reduces RI alpha protein, induces growth inhibition in SK-N-SH human neuroblastoma cells. To determine whether the reduction of RI alpha or protein kinase A isozyme type I is essential in the growth inhibition of SK-N-SH cells, we overexpressed RI alpha in sense and antisense orientation. Type I protein kinase A activity was increased in the RI alpha-overexpressing cells and was decreased in the RI alpha antisense-expressing cells. However, the changes in type I protein kinase A activities did not affect cell growth. Overexpression of RII beta or C alpha increased type II protein kinase A and inhibited cell growth in both cell lines regardless of the type I protein kinase A level. These results indicate that type II protein kinase A is the main effector in the cAMP-mediated growth regulation of SK-N-SH human neuroblastoma cells.

Iatrogenic secondary infertility caused by residual intrauterine fetal bone after midtrimester abortion

Eleven women with secondary infertility had ultrasonographic findings of intrauterine calcification. Infertility developed in all women after operative termination of midtrimester pregnancy. Dilation and curettage or hysteroscopic removal confirmed residual fetal bony fragments. The removal of these bony fragments was associated with therapeutic success for infertility.

Association between genetic variations of apo AI-CIII-AIV cluster gene and hypertriglyceridemic subjects

Several studies have suggested that genetic variations of the apolipoprotein (apo) AI-CIII-AIV cluster gene are associated with hyperlipidemia or atherosclerosis. These investigations were carried out mainly with Caucasian groups; there have been few associated studies involving non-Caucasian groups. This study was conducted to elucidate the association between five restriction fragment length polymorphisms (RFLPs) of the apo AI-CIII-AIV cluster gene and Korean hypertriglyceridemic subjects. The rare allele frequencies of the XmnI and SstI polymorphic sites in the patients were significantly higher than those of the control group (P <0.05). These two polymorphic sites had relation to linkage disequilibrium in the hypertriglyceridemic subjects (delta = -0.2733). In addition, S2 allele frequency of the SstI RFLP in Koreans was more frequent than that of Caucasians reported previously. The rare allele of XmnI and SstI polymorphic sites was associated with increased triglyceride concentrations in the hypertriglyceridemic group (P <0.005). Koreans have a much lower prevalence of hyperlipidemia than Caucasians. Nevertheless, this study showed a similar trend with results from Caucasian groups, thereby confirming that genetic variations of the apo AI-CIII-AIV cluster gene are likely to be significant markers for hypertriglyceridemic subjects. Thus, RFLP loci of the apo AI-CIII-AIV cluster gene may be a useful genetic marker for clinical or population studies.

Genetic variation of the angiotensin-converting enzyme gene: increased frequency of the insertion allele in Koreans

In view of the clinical importance of angiotensin-converting enzyme (ACE) as a major marker for cardiovascular diseases, we investigated insertion/deletion (I/D) polymorphism of the ACE gene in Koreans. Genotype frequencies were examined by polymerase chain reaction in 171 patients with coronary artery disease (CAD) and 120 healthy subjects. Allele frequencies of ACE polymorphism in Koreans were not significantly different between patient and control groups. In addition, association between ACE genotypes and the number of stenosed coronary arteries was not detected. ACE genotypes in the CAD group were not associated with body mass index and plasma lipid levels. Thus, our results suggest that, at least in Koreans, I/D polymorphism of the gene is unlikely to be a useful marker for CAD subjects. However, the I allele frequency of Koreans (0.58) was higher than that of Caucasian populations (0.47) but lower than that of Samoan (0.91) and Yanomami (0.85) populations. Here, we discuss the clinical and ethnic importance of ACE polymorphism.

Identification and expression of uvi31+, a UV-inducible gene from Schizosaccharomyces pombe

The Schizosaccharomyces pombe uvi31+ gene has been previously isolated as a UV-inducible gene [Lee JK et al. (1994) Biochem Biophys Res Commun 202:1113-1119]. This gene encodes a protein of about 12 kDa with 57% amino acid sequence similarity to Escherichia coli BolA protein which is known to be involved in switching between the cell elongation and septation systems during the cell division cycle. The putative Mlul cell cycle box (MCB), SWI4/6-dependent cell cycle box (SCB), and gear-box elements are found in the upstream region of uvi31+ gene, suggesting that this gene shows the cell cycle-regulated and growth phase-dependent expression. Interestingly, the level of uvi31+ transcript varies throughout the cell cycle, peaking in G1 phase before septation, and also shows the growth phase-dependent pattern during cellular growth, increasing maximally at the diauxic shift phase just before stationary phase. Furthermore, the transcript level of this gene is raised after S phase arrest, and is also increased maximally at 4 hr after UV irradiation of 240 J/m2. These results suggest that the delayed induction of uvi31+ gene after UV irradiation may be caused by cell cycle control of this gene after DNA replication checkpoint arrest. Thus, the uvi31+ gene may play a role in controlling the progress of the cell cycle after DNA damage (UV irradiation).

Proliferating cell nuclear antigen expression and its relationship to malignancy potential in invasive colorectal carcinomas

PURPOSE

Cellular proliferative activity is a useful indicator of biologic aggressiveness in colorectal carcinoma. Immunohistochemical analysis of proliferating cell nuclear antigen (PCNA) has important advantages of maintaining tissue architecture and technical simplicity. The aim of this study was to investigate the correlation between proliferative activity and malignancy potential in colorectal carcinomas to determine whether proliferative index of cancer cells has prognostic significance using immunohistochemical technique.

METHODS

Proliferation index at the invasive tumor margin of 86 paraffin sections of advanced colorectal carcinomas was assessed by immunohistochemical study using a mouse monoclonal antibody to PCNA (PC-10) and was compared with conventional clinicopathologic factors and other possible prognostic parameters, including p53 overexpression, tissue carcinoembryonic antigen immunoreactivity pattern, and flow cytometric DNA ploidy. In addition, recurrence and survival were analyzed in accordance with degree of PCNA expression.

RESULTS

PCNA labeling index (PCNA-LI) increased significantly as the Astler-Coller stage advanced (P = 0.0001). Strong correlations were observed between PCNA-LI and various pathologic parameters, including histologic differentiation (P = 0.0027), lymphatic invasion (P = 0.0001), vascular invasion (P = 0.0001), lymph node metastasis (P = 0.0001), and liver metastasis (P = 0.0036). Mean PCNA-LI was also significantly higher in tumors with DNA aneuploidy (P = 0.0006) and negative and cytoplasmic patterns of carcinoembryonic antigen immunoreactivity (P = 0.01). Linear relationships were demonstrated between PCNA-LI and clinical outcomes; recurrence rate was significantly greater in the group with higher than the mean PCNA-LI, who underwent curative resection (P < 0.01), and four-year survival rates for both overall and curative cases with higher than the mean PCNA-LI were significantly poorer than those with lower than mean PCNA-LI (P < 0.005 and P < 0.01, respectively).

CONCLUSION

Evaluation of PCNA-LI at the invasive tumor margin in colorectal carcinomas is suggested to be valuable in predicting those people with a higher potential for metastasis and recurrence after surgery; thus, the evaluation is helpful in planning reasonable adjuvant therapy, even in the earlier stages.

3-Deazaadenosine analogues inhibit the production of tumour necrosis factor-alpha in RAW264.7 cells stimulated with lipopolysaccharide

The effects of 3-deazaadenosine (DZA), 3-deaza(+/-)-aristeromycin (DZAri) and 3-deazaneplanocin (DZNep) on tumour necrosis factor-alpha (TNF-alpha) production were examined in the mouse macrophage cell line, RAW264.7, stimulated with lipopolysaccharide (LPS). The 3-deazaadenosine analogues inhibited the TNF-alpha production and the inhibition was dependent upon the concentration of the analogue. DZA reduced the level of TNF-alpha mRNA suggesting that DZA acts at a transcriptional step. In contrast, DZAri and DZNep had little effect on mRNA levels for TNF-alpha, implying that these compounds inhibit a post-transcriptional or translational biosynthetic step of TNF-alpha synthesis. The observation that homocysteine (Hcy) potentiated the DZA inhibition of TNF-alpha production and of TNF-alpha mRNA levels suggests that the inhibition of TNF-alpha production may be caused by elevated levels of 3-deazaadenosylhomocysteine (DZAHcy). The results show that the 3-deazaadenosine analogues are potent inhibitors of TNF-alpha production in the RAW264.7 cell line stimulated with LPS and suggest that these analogues may be effective agents for the treatment of diseases in which TNF-alpha plays an important pathogenic role.

Complementation of a yeast top2ts mutation by a cDNA encoding rat DNA topoisomerase II alpha

A series of yeast expression plasmids which comprise segments of the cDNA sequences encoding rat topo II alpha have been constructed. The transcription of these constructs is under the control of the yeast GAL1 promoter. Galactose-dependent expression of the cloned rat topo II alpha cDNA complemented a yeast top2ts mutation, as well as a deletion mutation at the yeast TOP2 locus. Truncation of 12 N-terminal amino acids and/or 158 C-terminal amino acids of rat topo II alpha had no effect on its ability functionally to substitute for top2ts. Moreover, a cDNA construct with mutated putative leucine zipper domain (amino acids 993-1013) retained the complementation activity. These observations suggest that transformants capable of conditional topo II alpha expression can be exploited as a useful model system for studies on the structure-function relationships of wild-type and mutated topo II alpha, as well as the interplay of potential antitumor drugs with the enzyme.

Psychosocial and demographic predictors of pediatric psychotropic medication use

The effects of age, gender, and family background on children's use of prescription psychoactive medications were studied. Patient and prescribing information was obtained for children enrolled as dependents in any of five prescription drug benefit plans during the period from December 29, 1992, through December 28, 1993. A binary response model was specified under the assumption of logistic distribution of probabilities of psychotropic drug use. The independent variables were family size, parenting type (single- or two-parent family), parental use of psychotropic medications, and child's age, gender, and the interaction between age and gender. Logistic regression analysis was conducted not only for overall psychotropic drug use but also for antidepressants, antianxiety drugs, and CNS stimulants. The sample included 3144 children; 3.9% received psychotropic drugs. Family size and parenting type had no effect on overall use of psychotropic drugs by children, but children were more likely to receive psychotropic drugs if the parents took them. The study showed an interaction between age and gender. At younger ages, boys were more likely than girls to receive psychotropic drugs; the opposite was true at older ages. For particular subcategories of drugs the study showed that (1) boys were more likely than girls, and young children were more likely than older children, to receive CNS stimulants, (2) children from single-parent families were less likely to use antidepressants than children from two-parent households, and (3) the influence of mothers' psychotropic drug use extended to all three drug classes, but the influence of fathers' psychotropic drug use existed for antidepressants only. The effects of demographic and familial factors on children's use of psychotropic drugs varied according to the drug class.

Topogenic effect of positively charged N-terminal amino acid in ER translocation of yeast alpha-factor precursor

Expression of fusion proteins between prepro-alpha-factor and somatostatin (SRIF) in yeast, resulted in the correct processing and secretion of the heterologous 14-amino acid SRIF peptide (1). When the chimeric genes were placed under the control of yeast acid phosphatase (PHO5) promoter, significant amount of an unglycosylated form of the fusion precursor molecule accumulated intracellularly, suggesting disruption of an endoplasmic reticulum-mediated function. We report here that the appearance of the precursor is due to an alteration in the three amino terminal residues of the chimera, i.e., Met-Arg-Phe in native prepro-alpha-factor is changed to Met-Phe-Lys in the hybrids. The unglycosylated precursor represents a population of molecules that are disrupted at an early stage of targeting to or translocation across the endoplasmic reticulum membrane. Our data demonstrate that the N-terminus plays an important role in topogenesis. Furthermore, these results show that translocation and glycosylation can be uncoupled from protein synthesis in vivo, and therefore can be posttranslational events in yeast.

Nucleotide sequence variation in the hypervariable region of the hepatitis C virus in the sera of chronic hepatitis C patients undergoing controlled interferon-alpha therapy

Ten patients with hepatitis C virus (HCV) infection (experimental group) were treated with interferon-alpha (IF-alpha). Dosage was six million units per day for one week and then three times a week for another six months. Seven HCV-infected patients (control group) did not receive IF-alpha therapy. The hypervariable region (HVR) of HCV in the sera of patients was amplified by reverse transcription-polymerase chain reaction (RT-PCR), and the variation of amino acid sequence in this region was determined. Serum alanine aminotransferase (ALT) activities in five patients treated for six months with IF-alpha fell to the normal range, when HCV was not detected in the sera of three patients. The nucleotide sequence variation in HVR of HCV in the sera of five patients who responded well to the IF-alpha therapy was relatively less than that in another five patients who did not respond to IF-alpha therapy and those in the control patients. These results indicate that the effectiveness of IF-alpha therapy was related to the sequence variation of HVR of HCV. This may have resulted from the selection pressure by humoral antibodies directed to HVR of HCV. It is concluded that the higher rate of sequence variation in HVR of HCV was compatible with a lower degree of effectiveness of IF-alpha therapy.

Identification of the DNA damage-responsive elements of the rhp51+ gene, a recA and RAD51 homolog from the fission yeast Schizosaccharomyces pombe

The Schizosaccharomyces pombe rhp51+ gene encodes a recombinational repair protein that shares significant sequence identities with the bacterial RecA and the Saccharomyces cerevisiae RAD51 protein. Levels of rhp51+ mRNA increase following several types of DNA damage or inhibition of DNA synthesis. An rhp51::ura4 fusion gene was used to identify the cis-acting promoter elements involved in regulating rhp51+ expression in response to DNA damage. Two elements, designated DRE1 and DRE2 (for damage-responsive element), match a decamer consensus URS (upstream repressing sequence) found in the promoters of many other DNA repair and metabolism genes from S. cerevisiae. However, our results show that DRE1 and DRE2 each function as a UAS (upstream activating sequence) rather than a URS and are also required for DNA-damage inducibility of the gene. A 20-bp fragment located downstream of both DRE1 and DRE2 is responsible for URS function. The DRE1 and DRE2 elements cross-competed for binding to two proteins of 45 and 59 kDa. DNase I footprint analysis suggests that DRE1 and DRE2 bind to the same DNA-binding proteins. These results suggest that the DRE-binding proteins may play an important role in the DNA-damage inducibility of rhp51+ expression.

Outpatient prescription drug use by children enrolled in five drug benefit plans

This study examined prescription drug use among ambulatory children younger than 18 years of age enrolled in five drug benefit plans. Data for this study were obtained from the pharmacy benefit manager who administers the drug benefit plans. During the study period of December 29, 1992, through December 28, 1993, 3144 children younger than 18 years of age (34.0% of the total plan enrollment) were enrolled in the five drug benefit plans. A total of 8547 prescription drugs were dispensed to the study population. The mean prescription price was $16.38, and the mean duration of therapy was 11.7 days. The mean prescription price was $1.56 more for boys than for girls. The most frequently dispensed drugs were antibiotics (42.0%), followed by cold preparations (15.9%). The annual prevalence rate of prescription drug use was 59.1 cases per 100 children. The study population-based annual frequency rate was 3.2 prescriptions per child, and the drug user-based annual frequency rate was 5.5 prescriptions per child. The annual expenditures were $51.85 per child and $90.39 per drug users, with the out-of-pocket expenditures being $19.09 and $33.04, respectively. The prevalence rate varied little by sex. However, both frequency and expenditure rates differed by sex and decreased with age. Higher levels of cost sharing per prescription were associated with higher prevalence, frequency, and expenditure rates. Larger cost-sharing differentials between generic and brand name drugs were associated with higher rates of generic drug use but were not always associated with lower expenditure rates.

Differential expression of the rhp51+ gene, a recA and RAD51 homolog from the fission yeast Schizosaccharomyces pombe

The rhp51+ gene encodes three transcripts of 1.9, 1.6 and 1.3 kb which have at least six polyadenylation sites. Primer-extension analysis revealed that two transcription start points (tsp) at - 166 and - 136 were responsible for the DNA damage inducibility of this gene. Northern blot analyses showed that the three transcripts were expressed differentially in response to a variety of DNA damage. During the mitotic cell cycle, only the largest transcript exhibited periodic expression, reaching the maximal level in front of the cdc22+ transcript which peaks at the G1/S boundary. Unexpectedly, the steady-state levels of the three transcripts were differentially regulated during the growth cycle. The largest and smallest transcripts accumulated in large quantity at the diauxic shift and during the entry into stationary phase, respectively. To localize the regions responsible for the differential expression of rhp51+, we constructed rhp51::ura4 and ura4::rhp51 hybrid genes, and analyzed their expression patterns in response to methyl methanesulfonate (MMS)-induced DNA damage. The results showed that the promoter region and 5' half of rhp51+ are sufficient to confer damage-responsiveness while the 3' end of the gene alone can direct the formation of multiple, discrete 3' ends of the transcripts. From these results, we conclude that this novel one gene-multiple product system is possible through the cooperation of both the promoter and 3' terminal regions.

Evidences for possible involvement of Rhp51 protein in mitotic events including chromosome segregation

To understand the role of the Rhp51 protein in Schizosaccharomyces pombe, we examined the phenotypes of the null mutant for the rhp51+ gene. Unlike Saccharomyces cerevisiae rad51 mutants, S. pombe rhp51 mutants (rhp51delta cells) displayed slow growth and heterogeneity in cell size, indicating perturbation of the cell cycle. Furthermore, many aberrant nuclear structures found in 4',6'-diamidino-2-phenylindole (DAPI)-stained rhp51delta cells and the caffeine hypersensitivity of the mutant cells suggested an involvement of the Rhp51 protein in normal chromosome segregation. These data suggested that the Rhp51 proteins were required for normal cell growth as well as a DNA repair pathway. Moreover, rhp51delta mutants showed a considerable sensitivity to ultraviolet (UV) light-irradiation as well as methyl methanesulfonate (MMS) treatment, indicating that the Rhp51 proteins are involved in both the active excision mechanism of UV-induced DNA damage and recombinational repair in S. pombe. Taken together, we suggest that the role(s) of the Rhp51 protein in S. pombe may be different from those of Rad51 in S. cerevisiae.

Isolation and characterization of the promoter region of the rat DNA topoisomerase II alpha gene

A genomic DNA clone containing the 5'-end of the rat topo II alpha gene was isolated and the intron/exon structure of a 4.0 kb region encompassing the translation initiation site was determined. Multiple transcription initiation sites were found at positions -128, -110, and -100 bp upstream of the ATG codon. A minimal promoter region extending from -192 to the translation initiation codon was identified on transient expression analysis. This region lacks a TATA motif, is moderately GC-rich and contains a high number of CpG dinucleotides, which is characteristic of a housekeeping gene promoter. The fragment extending to position -242 exhibited maximal promoter activity. Putative regulatory elements were delineated within and immediately upstream of the minimal promoter region. On gel retardation and DNase I footprint analyses, two regions, between positions -195 to -159 which interact with protein factor(s) were identified. The minimal promoter region of the rat topo II alpha gene showed high sequence homology with that of human topo II alpha. In a 250 bp region upstream of the translation initiation site, the sequence identity was about 70%. The basic structure of the regulatory region of the rat topo II alpha gene was found to be similar to that of the human counterpart.

A simple and efficient method for the isolation of total RNA from the fission yeast Schizosaccharomyces pombe

A simple and efficient procedure was described for the isolation of total RNA from the fission yeast Schizosaccharomyces pombe. The present study demonstrated that the quality and the quantity of S. pombe RNA were increased by substituting phenol/chloroform mixture for phenol as a deproteinizing agent in the first vortexing step and using an ice bath instead of a dry ice-ethanol bath in the freezing step. Additionally, this protocol had the advantage of extracting total RNA without any degradation of S. pombe cells. Furthermore, the high amounts and quality of RNA extracted by this modified procedure enabled us to perform some experiments such as Northern blot, S1 mapping, primer extension, and reverse transcriptase reaction-polymerase chain reaction (RT-PCR) without further RNA purification. We suggest that this procedure is very useful to analyse primary structures and steady-state levels of RNA from S. pombe.

Characterization of SFP2, a putative sulfate permease gene of Saccharomyces cerevisiae

The SFP2 gene of Saccharomyces cerevisiae has been characterized. The deduced amino acid sequence contained twelve highly hydrophobic domains and showed 50, 47, 44 and 48% homologies to Neurospora crassa sulfate permease II (CYS14), soybean GMAK170 nodulin, human colon mucosa protein (DRA) and a putative open reading frame (ORF) downstream of Escherichia coli prs (phosphoribosyl pyrophosphatate synthetase) gene, respectively, in the aligned regions. Cells lacking SFP2 were viable and displayed no obvious decrease in their growth rate. Southern blot analysis revealed that SFP2 exists as a single copy in haploid genome. Northern blot analysis showed that SFP2 produced a 2.8-kb transcript which was highly expressed under sulfur derepressing condition. SFP2 mRNA was found to turn over with a half-life of approximately 15 min, which may contribute to the regulation of sulfate permease function, and reached its maximal level in about 22 h after depression.

Effects of topical nasal decongestants on histology of nasal respiratory mucosa in rabbits

The aim of this study was to evaluate histologic changes after long-term administration of the topical nasal decongestants phenylephrine and oxymetazoline. Ninety healthy rabbits were divided into 3 groups for topical administration for 1 week, 2 weeks, and 4 weeks. Each group was subdivided into 3 subgroups by topical administration of phenylephrine. oxymetazoline, and physiologic saline as controls. Each study group thus consisted of 10 rabbits. Phenylephrine was administered by 2 puffs in the left nostril 5 times daily and oxymetazoline by 2 puffs twice a day using metered sprayers giving 0.10 ml in each puff with a dosage used in clinical practice. For statistical significance the Kolmogorov-Smirnov test was used. Light and electron microscopic examination were performed after obtaining nasal respiratory mucosa from the nasal septum of the rabbits. Administration of phenylephrine and oxymetazoline for more than 2 weeks caused histologic changes including ciliary loss, epithelial ulceration, inflammatory cell infiltration and subepithelial edema, and the changes were more pronounced with increasing administration duration of the decongestants. Ciliary loss was prominent in the 4-week phenylephrine and oxymetazoline groups. There were significantly severer changes in the morphologic variables in the decongestant groups compared with the control group according to administration duration (p < 0.05). Dilatation or vacuolization of mitochondria and endoplasmic reticula and vesicles ill the cytoplasm were observed in the 2- and 4-week phenylephrine groups as well as the 2- and 4-week oxymetazoline groups. Mild widening of the intercellular space was observed in the 4-week phenylephrine group. Purulent maxillary sinusitis developed in 6 of 10 rabbits treated for 4 weeks with phenylephrine. The results of this study suggest that the administration of decongestants may cause ciliary loss with subsequent inflammatory changes in the nasal respiratory mucosa.

Biochemical characteristics of four common molecular variants in glucose-6-phosphate dehydrogenase-deficient Chinese in Singapore

Biochemical characteristics were determined for four common molecular variants of glucose-6-phosphate dehydrogenase (G6PD) deficiency and 10 non-deficient Chinese males in Singapore. The variants included one Mediterranean (nt563 C-->T), two Canton (G-->T at nt1376) and one each of Kaiping (1388 G-->A) and Chinese-5 (1024 C-->T) variants. Molecular identification was carried out by amplication of genomic DNA with specific oligonucleotide primers followed by digestion with restriction enzymes that recognize artificially created or naturally occurring restriction sites. All the variants had low enzyme activity in red cells (0.2-0.6 IU/g Hb). All but the Chinese-5 variant (nt1024) had a normal Km for NADP (7-10 microM). The Mediterranean variant had a high utilization of deamino-NADP (296%), followed by the Canton variant 1376 substitution (131%). The Km for glucose-6-phosphate was low in the Mediterranean and 1376 variant (18-40 microM) but high in the 1024 substitution (104 microM). Electrophoretic mobility in TEB buffer (pH 8.6) was slightly faster (103%) for the 1376 mutation while 100% for all the others. All but the 1024 substitution had increased analogue utilization for galactose-6-phosphate and 2-deoxy-glucose-6-phosphate (58 and 68% for the Mediterranean mutation and 14-23% for the 1376 and 1388 substitutions, respectively), and reduced heat stability.

A 33 kDa Pit-1-like protein binds to the distal region of the human thyrotrophin alpha-subunit gene

Our previous studies demonstrated that at least two DNA regions with upstream limits between positions -223 to -190 and positions -151 to -135 of the human TSH gene are important for transcriptional regulation by TRH in GH3 rat pituitary cells. The proximal region (-151 to -135 bp) including the cAMP-responsive element (CRE) was required for the induction of the TSH gene by TRH, while the distal region (-223 to -190 bp) containing an element similar to the binding site for the pituitary-specific transcription factor, Pit-1, was necessary to amplify the effects of TRH. To determine whether a pituitary-specific nuclear protein, in addition to the CRE-binding protein, is involved in the molecular mechanism of TRH regulation, a gel retardation assay and Southwestern blot analysis were performed on the distal region with GH3 cell nuclear extracts. GH3 extracts generated a distinct DNA-protein complex that was effectively eliminated in the presence of excess unlabelled DNA fragment, and TRH treatment increased the affinity of protein binding remarkably. Excess Pit-1 DNA-binding sequence from the rat prolactin gene inhibited formation of the complex, but mutation of the Pit-1 consensus sequence in the distal region did not eliminate the complex. In addition, Southwestern experiments showed that a 33 kDa nuclear protein present in GH3 cells bound to this region and its binding affinity was increased slightly 2 h after TRH treatment, with the maximal increase (fivefold) at 3 h, which was similar to the results when using gel retardation. Phosphatase treatment of nuclear protein also resulted in a loss of binding affinity. Taken together, these data indicate that the interaction of a pituitary-specific nuclear protein, identical or closely related to Pit-1, with the distal region may be involved in the TRH stimulation of human TSH gene expression.