Genetic Determinants of Type 2 Diabetes in Asians

Type 2 diabetes (T2D) has become a major health problem throughout the world and the epidemic is particularly severe in Asian countries. Compared with European populations, Asians tend to develop diabetes at a younger age and at much higher incidence rates given the same amount of weight gain. Genome-wide association studies (GWAS) have identified over 70 loci associated with T2D. Although the majority of GWAS results were conducted in populations of European ancestry, recent GWAS in Asians have made important contributions to the identification of T2D susceptibility loci. These studies not only confirmed T2D susceptibility loci initially identified in European populations, but also identified novel susceptibility loci that provide new insights into the pathophysiology of diseases. In this article, we review GWAS results of T2D conducted in East and South Asians and compare them to those of European populations. Currently identified T2D genetic variants do not appear to explain the phenomenon that Asians are more susceptible to T2D than European populations, suggesting further studies in Asian populations are needed.

Clinical implications of systemic inflammatory response markers as independent prognostic factors for advanced pancreatic cancer

BACKGROUND

Cancer-associated inflammation is a key molecular feature of pancreatic ductal adenocarcinoma. In this study, we systematically evaluated the prognostic relevance of systemic inflammatory response (SIR) markers in patients with advanced pancreatic cancer.

METHODS

A total of 321 consecutive patients with pathologically-confirmed locally advanced or metastatic pancreatic adenocarcinoma were retrospectively recruited. The patients were divided into a test set (n = 110) and a validation set (n = 211). The associations between overall survival (OS) and clinically available SIR markers including white blood cell (WBC) count, absolute neutrophil count, absolute lymphocyte count, absolute monocyte count, platelet count, neutrophil-lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR) and lymphocyte/monocyte ratio (LMR) were analyzed using Kaplan-Meier curves and multivariate Cox proportional models.

RESULTS

High WBC count, neutrophil count, monocyte count, NLR, PLR and low LMR were significantly associated with decreased OS in the test set. Using the validation set for confirmation, we found also in multivariate analysis an independent value of WBC count (hazard ratio (HR): 2.176, 95% confidence interval (CI): 1.560-3.035, P < 0.001), neutrophil count (HR: 2.807, 95% CI: 2.000-3.940, P < 0.001), monocyte count (HR: 1.848, 95% CI: 1.315-2.598, P < 0.001), NLR (HR: 2.204, 95% CI: 1.590-3.055, P < 0.001), PLR (HR: 1.537, 95% CI: 1.114-2.122, P = 0.009) and LMR (HR: 0.569, 95% CI: 0.412-0.784, P = 0.001) for OS in patients with advanced pancreatic cancer.

CONCLUSIONS

Our study confirmed that SIR markers can be used to determine optimal therapeutic strategies for individual patients and to predict pancreatic cancer prognosis.

Non-invasive prenatal testing for fetal aneuploidies in the first trimester of pregnancy

OBJECTIVES

To evaluate the feasibility of non-invasive prenatal testing (NIPT) of maternal plasma samples collected from pregnant Chinese women in early gestation, between 8 + 0 and 12 + 6 weeks' gestation.

METHODS

In this pilot study, 212 women with high-risk pregnancies were recruited at a single Chinese Hospital. Fetal aneuploidies associated with chromosomes 21, 18, 13, X and Y were detected by massively parallel sequencing of maternal plasma DNA samples. Invasive prenatal diagnosis by either chorionic villus sampling or amniocentesis and then karyotyping was offered to all women to confirm both positive and negative NIPT results. Fetal DNA fraction was also determined in male pregnancies, by the relative percentage of Y-chromosome sequences. All confirmed NIPT-negative pregnancies were followed up to birth and neonates were clinically evaluated for any symptoms of chromosomal disease.

RESULTS

Autosomal aneuploidies trisomy 21 (n = 2), 18 (n = 1) and 13 (n = 1) were detected by NIPT and confirmed by amniocentesis and karyotyping. There were one false-positive 45,X sample and two false-negative samples associated with fetal karyotypes 47,XXY and 45,X[16]/47,XXX[14]. In the 100 male pregnancies, the median fetal DNA fraction was 8.54% and there was a trend towards an increasing fetal fraction from 8 + 0 to 12 + 6 weeks' gestation. The majority (95%) of pregnancies had a fetal DNA fraction > 4%, which is generally the limit for accurate aneuploidy detection by NIPT. Across this early gestational time period, there was a weak inverse relationship (R(2)  = 0.186) between fetal DNA fraction and maternal weight.

CONCLUSIONS

NIPT is highly reliable and accurate when applied to maternal DNA samples collected from pregnant women in the first trimester between 8 + 0 and 12 + 6 weeks.

Merlin sumoylation is required for its tumor suppressor activity

Merlin, encoded by the Neurofibromatosis 2 (NF2) gene, is a multifunctional tumor suppressor that integrates and regulates extracellular cues and intracellular signaling pathways, both at the plasma membrane and in the nucleus, to control cell proliferation, migration and invasion. Molecular mechanisms regulating merlin's tumor-suppressive activity have not been clearly defined. Here we report that merlin can be sumoylated on Lysine residue (K76) in vitro and in vivo. Sumoylation mediates merlin's intramolecular and intermolecular binding activities and regulates its cytoplasm/nucleus trafficking. Interestingly, sumoylation of merlin is regulated by its phosphorylation via Akt and PAK2 kinases. Mutation of K76 into arginine (R) abolishes its sumoylation, disrupts merlin cortical cytoskeleton residency and attenuates its stability. Using a K76R mutant merlin in a subcutaneous U87MG xenograft model, we demonstrate that merlin sumoylation is required for tumor-suppressive activity. Taken together, our findings indicate that merlin is sumoylated and that this post-translational modification is essential for tumor suppression.

Lipoprotein receptor-related protein 1 variants and dietary fatty acids: meta-analysis of European origin and African American studies

OBJECTIVE

Low-density lipoprotein-related receptor protein 1 (LRP1) is a multi-functional endocytic receptor and signaling molecule that is expressed in adipose and the hypothalamus. Evidence for a role of LRP1 in adiposity is accumulating from animal and in vitro models, but data from human studies are limited. The study objectives were to evaluate (i) relationships between LRP1 genotype and anthropometric traits, and (ii) whether these relationships were modified by dietary fatty acids.

DESIGN AND METHODS

We conducted race/ethnic-specific meta-analyses using data from 14 studies of US and European whites and 4 of African Americans to evaluate associations of dietary fatty acids and LRP1 genotypes with body mass index (BMI), waist circumference and hip circumference, as well as interactions between dietary fatty acids and LRP1 genotypes. Seven single-nucleotide polymorphisms (SNPs) of LRP1 were evaluated in whites (N up to 42 000) and twelve SNPs in African Americans (N up to 5800).

RESULTS

After adjustment for age, sex and population substructure if relevant, for each one unit greater intake of percentage of energy from saturated fat (SFA), BMI was 0.104 kg m(-2) greater, waist was 0.305 cm larger and hip was 0.168 cm larger (all P<0.0001). Other fatty acids were not associated with outcomes. The association of SFA with outcomes varied by genotype at rs2306692 (genotyped in four studies of whites), where the magnitude of the association of SFA intake with each outcome was greater per additional copy of the T allele: 0.107 kg m(-2) greater for BMI (interaction P=0.0001), 0.267 cm for waist (interaction P=0.001) and 0.21 cm for hip (interaction P=0.001). No other significant interactions were observed.

CONCLUSION

Dietary SFA and LRP1 genotype may interactively influence anthropometric traits. Further exploration of this, and other diet x genotype interactions, may improve understanding of interindividual variability in the relationships of dietary factors with anthropometric traits.

Combined effects of 17 common genetic variants on type 2 diabetes risk in a Han Chinese population

AIMS/HYPOTHESIS

The recent advent of genome-wide association studies has considerably accelerated the identification of type 2 diabetes loci. We aimed to investigate the combined effects of multiple genetic variants, alone or in combination with conventional risk factors, on type 2 diabetes and diabetes-related traits in Han Chinese.

METHODS

We genotyped 17 variants in 17 loci in a population-based Han Chinese cohort including 3,210 unrelated individuals. A genetic risk score (GRS) was calculated on the basis of these variants. The discriminatory ability was assessed by the area under the receiver operating characteristics curve.

RESULTS

The odds ratio for type 2 diabetes and hyperglycaemia with each GRS point (per risk allele) was 1.18 (95% CI 1.12-1.23, p = 1.3 x 10(-12)) and 1.12 (95% CI 1.09-1.16, p = 7.5 x 10(-14)), respectively. Compared with participants with GRS < or =11.0 (7.63%), those with GRS > or =19.0 (8.87%) had a 4.58-fold higher risk (95% CI 2.49-8.42) of type 2 diabetes. The GRS also showed a significant association with lower beta cell function estimated by HOMA of beta cell function (p = 8.4 x 10(-10)). In addition, we observed significant interactive effects between GRS and BMI on fasting glucose and HbA(1c) levels (p = 0.04 and p = 0.03 for interaction, respectively). Discrimination of diabetes risk was improved (p < 0.001) when the GRS was added to a model including clinical risk factors. The AUCs were 0.62 and 0.77, respectively, for the GRS and conventional clinic risk factors alone, and 0.79 when the GRS was added.

CONCLUSIONS/INTERPRETATION

In this Han Chinese population, the GRS of 17 combined variants modestly but significantly improved discrimination of the conventional risk factors for type 2 diabetes.

Association of GCKR rs780094, alone or in combination with GCK rs1799884, with type 2 diabetes and related traits in a Han Chinese population

AIMS/HYPOTHESIS

The GCKR rs780094 and GCK rs1799884 polymorphisms have been reported to be associated with dyslipidaemia and type 2 diabetes in white Europeans. The aim of this study was to replicate these associations in Han Chinese individuals and to identify the potential mechanisms underlying these associations.

METHODS

The single nucleotide polymorphisms rs780094 and rs1799884 were genotyped in a population-based sample of Han Chinese individuals (n = 3,210) and tested for association with risk of type 2 diabetes and related phenotypes.

RESULTS

The GCKR rs780094 A allele was marginally associated with reduced risk of type 2 diabetes (OR 0.85, 95% CI 0.73-1.00, p value under an additive model [p((add))] = 0.05) and significantly associated with reduced risk of impaired fasting glucose (IFG) or type 2 diabetes (OR 0.86, 95% CI 0.77-0.96, p([add]) = 0.0032). It was also significantly associated with decreased fasting glucose and increased HOMA of beta cell function (HOMA-B) and fasting triacylglycerol levels (p([add]) = 0.0169-5.3 x 10(-6)), but not with HOMA of insulin sensitivity (HOMA-S). The associations with type 2 diabetes and IFG remained significant after adjustment for BMI, while adjustment for HOMA-B abolished the associations. The GCKR rs780094 was also associated with obesity and BMI, independently of its association with type 2 diabetes. The GCK rs1799884 A allele was significantly associated with decreased HOMA-B (p([add]) = 0.0005), but not with type 2 diabetes or IFG. Individuals with increasing numbers of risk alleles for both variants had significantly lower HOMA-B (p([add]) = 5.8 x 10(-5)) in the combined analysis.

CONCLUSIONS/INTERPRETATION

Consistent with observations in white Europeans, the GCKR rs780094 polymorphism contributes to the risk of type 2 diabetes and dyslipidaemia in Han Chinese individuals. In addition, we showed that the effect on type 2 diabetes is probably mediated through impaired beta cell function rather than through obesity.

Predictors of the scleroderma phenotype in fibroblasts from systemic sclerosis patients

BACKGROUND

Fibroblasts from skin lesions generally exhibit the scleroderma phenotype in the early stage of in vitro culture, and act as one of the most important samples to investigate systemic sclerosis. However, not all cell lines from patients show the scleroderma phenotype, and little prospective evidence can be relied on to predict the phenotype of fibroblasts from systemic sclerosis patients.

OBJECTIVE

This study aims to find the predictive factors related to fibroblast phenotypes.

METHODS

Fibroblast lines from 15 patients with systemic sclerosis were established through explant culture, with their scleroderma phenotypes being determined by real-time reverse transcription-polymerase chain reaction (RT-PCR) of procollagen transcription. Logistic regression analysis was used to analyse the clinical data of these patients. Haematoxylin-eosin staining was performed to observe histopathological differences. Expression of methylation-related factors was detected by real-time reverse transcription-polymerase chain reaction.

RESULTS

Eight of the 15 fibroblast cell lines from patients with systemic sclerosis exhibited the scleroderma phenotype. Logistic regression analysis yielded an equation (Y = -9.718 + 2.525X1) in which X1 significantly represents the Valentini Disease Activity Index. Histopathology results demonstrated that the scleroderma phenotype was positively correlated with leucocyte infiltration. Further laboratory observations showed increased expression of Dnmt1 in the positive phenotype fibroblasts and a positive correlation between elevations of Dnmt1 and the maintenance period of the scleroderma phenotype.

CONCLUSIONS

The results of this study suggest that the Valentini Disease Activity Index and expression of Dnmt1 may act as indicators of the scleroderma phenotype in fibroblasts. Additionally, these data also imply that epigenetic factors, such as Dnmt1, may be involved in the maintenance of the scleroderma phenotype. Our analyses may be beneficial to the research in systemic sclerosis.

Autoantibodies and neuropsychiatric events at the time of systemic lupus erythematosus diagnosis: results from an international inception cohort study

OBJECTIVE

To examine, in an inception cohort of systemic lupus erythematosus (SLE) patients, the association between neuropsychiatric (NP) events and anti-ribosomal P (anti-P), antiphospholipid (lupus anticoagulant [LAC], anticardiolipin), anti-beta2-glycoprotein I, and anti-NR2 glutamate receptor antibodies.

METHODS

NP events were identified using the American College of Rheumatology case definitions and clustered into central/peripheral and diffuse/focal events. Attribution of NP events to SLE was determined using decision rules of differing stringency. Autoantibodies were measured without knowledge of NP events or their attribution.

RESULTS

Four hundred twelve patients were studied (87.4% female; mean +/- SD age 34.9 +/- 13.5 years, mean +/- SD disease duration 5.0 +/- 4.2 months). There were 214 NP events in 133 patients (32.3%). The proportion of NP events attributed to SLE varied from 15% to 36%. There was no association between autoantibodies and NP events overall. However, the frequency of anti-P antibodies in patients with central NP events attributed to SLE was 4 of 20 (20%), versus 3 of 107 (2.8%) in patients with other NP events and 24 of 279 (8.6%) in those with no NP events (P = 0.04). Among patients with diffuse NP events, 3 of 11 had anti-P antibodies (27%), compared with 4 of 111 patients with other NP events (3.6%) and 24 of 279 of those with no NP events (8.6%) (P = 0.02). Specific clinical-serologic associations were found between anti-P and psychosis attributed to SLE (P = 0.02) and between LAC and cerebrovascular disease attributed to SLE (P = 0.038). There was no significant association between other autoantibodies and NP events.

CONCLUSION

Clinically distinct NP events attributed to SLE and occurring around the time of diagnosis were found to be associated with anti-P antibodies and LAC. This suggests that there are different autoimmune pathogenetic mechanisms, although low sensitivity limits the clinical application of testing for these antibodies.

Relapse patterns and outcomes in a population-based study of Nova Scotia patients with germ cell tumors (GCT)

15564

Objectives: To examine the frequency and pattern of relapse in a population-based cohort of Nova Scotia patients with germ cell tumors (GCT). Presentation and outcome of these patients will be described with an emphasis on late relapsers. Methods: A retrospective chart review of all patients diagnosed with GCT in Nova Scotia between 1984 and 2004 was completed. Data regarding initial diagnosis and treatment as well as data at time of relapse was collected. Relapse was defined as any recurrence of tumor after initial definitive therapy. Late relapse (LR) was defined as a relapse >2 years from initial definitive therapy or previous relapse. Results: Of the 383 patients diagnosed with GCT during the 20 year period, 135 received chemotherapy. 15/135 (3.7%) patients initially treated with chemotherapy relapsed; 10 early and 5 late. 1/10 early relapsers was alive and NED at 2 years from relapse compared to 4/ 5 late relapsers at 4 years. 3 of the 245 patients whose treatment did not include chemotherapy experienced a LR for a total of 8/383 (2.1%) of all patients. Median time to all LR was 6.6 years. Pathology for 6/8 (75%) patients with LR was nonseminomatous GCT. 50% of patients with LR died. Common to all LR survivors was complete surgical resection ± chemotherapy. All patients with LR who died had either no surgical resection or incomplete surgical resection of disease. Conclusions: The incidence of all GCT patients with LR was 2.1% and the incidence of LR post chemotherapy was 3.7% in this population. The only other population based report of incidence of LR in all GCT patients was 1.3%. A mixture of stages, pathology, and sites of metastases was observed with no obvious baseline or treatment differences between early and late relapsers. Interestingly, in this population, patients with LR had better outcomes than early relapsers. The success to curing patients with LR appears to be complete surgical resection of disease.

No significant financial relationships to disclose.

Detection of Hong Kong 97-like H5N1 influenza viruses from eggs of Vietnamese waterfowl

Three H5N1 influenza viruses were isolated from shell washes of duck and goose eggs confiscated from travelers coming from Vietnam. All eight gene segments of these viruses share high sequence identity with the H5N1 avian influenza viruses that caused outbreaks in poultry and humans in Hong Kong in 1997. Animal studies indicate that these isolated viruses are able to replicate in mouse lung and could be found in the organs of ducks without causing any clinical signs or death. However, the viruses are highly pathogenic for chickens. Although the source of these recently isolated Hong Kong 97-like H5N1 viruses is undetermined, their detection in the egg shell of duck and goose suggests that this particular genotype of H5N1 virus may have re-emerged in nature or may have been circulating continuously.

[Acoustic analysis in patients with trauma to unilateral cricoarytenoid joint by computer technique]

OBJECTIVE

To investigate the acoustic characteristics of unilateral cricoarytenoid joint trauma and evaluate the effect of acoustic analysis technique on the diagnosis and treatment of this disease.

METHOD

The voice signals of sustained vowel [a] were measured using a micro-computer with Dr. Speech software in 50 healthy adults and 30 patients with unilateral cricoarytenoid joint trauma. The acoustic parameters (jitter, shimmer and NNE) and spectrographic characteristics (harmonic waves, formants and noise) were analyzed. The acoustic changes before and after the treatment of arytenoid motion were observed and compared.

RESULT

All acoustic parameters were significantly increased in trauma of unilateral cricoarytenoid joint. The pathologic spectrograph showed decrease or loss of harmonic waves and formants, and increase of noise, in middle and high frequencies. There was a relationship between NNE and the position of the vocal cord. After the treatment of arytenoid motion, 33% patients were cured and had normal acoustic parameters and spectrograph. 47% were improved with reduced parameters and improved spectrograph. The acoustics in 20% cases didn't change at all after treatment. The acoustic parameters were significantly decreased after the treatment of arytenoid motion.

CONCLUSION

The present study suggested that the acoustic parameters may estimating the degrees of voice lesion as objective standards and NNE may judge the degree of glottic closure. Both acoustic parameters and spectrograph are of value in the diagnosis, treatment effect and prognosis observation to cricoarytenoid joint trauma.

Polyhydroxybutyrate biosynthesis in Caulobacter crescentus: molecular characterization of the polyhydroxybutyrate synthase

Caulobacter crescentus was investigated with respect to polyhydroxybutyrate (PHB) biosynthesis. Polyhydroxyalkanoate (PHA) accumulation contributing to approximately 18% of the cell dry weight was obtained in the presence of glucose. Gas chromatography-mass spectrometry and gel permeation chromatography of the purified PHA showed that this polyester was solely composed of 3-hydroxybutyrate and had a weight average molar mass of 5.5 x 10(5) g mol(-1) and a polydispersity of 1.6. An ORF encoding a conserved, hypothetical protein which shared approximately 47% identity with the PHB synthase from Azorhizobium caulinodans was identified within the complete C. crescentus genomic sequence. This putative C. crescentus PHB synthase gene, phaC, consisted of a 2019 nt stretch of DNA (encoding 673 aa residues), which encoded a PHB synthase with a molecular mass of approximately 73 kDa. This is currently the largest PHA synthase identified. The phaC coding region was subcloned into vector pBBR1-JO2 under lac promoter control. The resulting plasmid, pQQ4, mediated PHB accumulation in the mutant Ralstonia eutropha PHB(-)4 and recombinant Escherichia coli JM109(pBHR69), which produced the beta-ketothiolase and acetoacetyl-CoA reductase from R. eutropha, contributing to approximately 62% and 6% of cell dry weight, respectively. Functional expression of the coding region of phaC was confirmed by immunoblotting and in vitro PHB synthase activity.

[Advances on the biological effect indices for fine particles (PM2.5) in air]

Fine particles are complex mixture of air pollutants containing not only a great deal of organic compounds but also varied kind of metals, such as B(a)p, Pb, Cd, Cr etc. Most of those compounds are toxic. Some of them are the cause of lung inflammation and asthma, some are genotoxic with a potential of carcinogenesis. Because the fine particles can be inhaled into lung and deposit in lung tissue, which have adverse effects on human health. Epidemiological studies indicated that increased mortality and morbidity, especially for cardiovascular and lung diseases, was associated with the amount of ambient fine particles. Although some scientists thought fine particles damaging the body through oxidant stress, inflammation and genetic materials and so on, the mechanism for them is not known well. Therefore, it is necessary to explore the biological effects of fine particle on human health in the future.

Identification of a new urinary metabolite of carbon disulfide using an improved method for the determination of 2-thioxothiazolidine-4-carboxylic acid

A new method is reported for the analysis of 2-thioxothiazolidine-4-carboxylic acid (TTCA) in urine that is amenable to automation and provides greatly simplified chromatograms. The method comprises the addition of tetrahydro-2-thioxo-2H-1,3-thiazine-4-carboxylic acid, which is chemically similar to TTCA, as internal standard, purification on an Oasis HLB solid-phase extraction column, and analysis by HPLC with UV detection. The limit of detection for TTCA was 40 pmol/mL of urine, recovery was 79.3 +/- 1.0%, and detection was linear over at least 3 orders of magnitude. In addition, during the analysis of urine samples from workers exposed to CS(2), a novel urinary metabolite of CS(2) was recognized. The new metabolite demonstrated a dose response, was present at approximately 30% the level of TTCA, and was charaterized to be 2-thioxothiazolidin-4-ylcarbonylglycine (TTCG). Administration of TTCG to rats resulted in excretion of TTCA suggesting that TTCG is a likely precursor of TTCA. Although urinary excretion of both TTCA and TTCG resulted from administration of captan, only TTCA was detected following administration of methyl isothiocyanate. The greater selectivity of TTCG suggests that co-analysis of TTCA and TTCG in urine may aid in differentiating exposures to CS(2), captan and isothiocyanates.

Induction of unspliced c-fos messenger RNA in rodent brain by kainic acid and lipopolysaccharide

The c-fos transcriptional factor forms an activator protein-1 (AP-1) complex with proteins from the Jun family, which plays an important role in the central nervous system. The responses of AP-1 transcriptional factors induced by kainic acid (KA) treatment have been well studied, although the transcriptional regulation of these KA-induced factors has not been clearly characterized. To investigate the role of different stimuli in controlling of the splicing of c-fos mRNA, we performed reverse transcriptional polymerase chain reaction. The results showed that spliced and unspliced c-fos is present in rat brain following KA treatment and in lipopolysaccharide (LPS)-treated primary mouse cortical brain cell cultures. Furthermore, tyrosine kinase and protein phosphatase inhibitors alter the preponderance of c-fos transcripts following LPS treatment.

Matrix-assisted in vitro refolding of Pseudomonas aeruginosa class II polyhydroxyalkanoate synthase from inclusion bodies produced in recombinant Escherichia coli

In order to facilitate the large-scale preparation of active class II polyhydroxyalkanoate (PHA) synthase, we constructed a vector pT7-7 derivative that contains a modified phaC1 gene encoding a PHA synthase from Pseudomonas aeruginosa possessing six N-terminally fused histidine residues. Overexpression of this phaC1 gene under control of the strong Ø10 promoter was achieved in Escherichia coli BL21(DE3). The fusion protein was deposited as inactive inclusion bodies in recombinant E. coli, and contributed approx. 30% of total protein. The inclusion bodies were purified by selective solubilization, resulting in approx. 70-80% pure PHA synthase, then dissolved and denatured by 6 M guanidine hydrochloride. The denatured PHA synthase was reversibly immobilized on a Ni(2+)-nitrilotriacetate-agarose matrix. The matrix-bound fusion protein was refolded by gradual removal of the chaotropic reagent. This procedure avoided the aggregation of folding intermediates which often decreases the efficiency of refolding experiments. Finally, the refolded fusion protein was eluted with imidazole. The purified and refolded PHA synthase protein showed a specific enzyme activity of 10.8 m-units/mg employing (R/S)-3-hydroxydecanoyl-CoA as substrate, which corresponds to 27% of the maximum specific activity of the native enzyme. The refolding of the enzyme was confirmed by CD spectroscopy. Deconvolution of the spectrum resulted in the following secondary structure prediction: 10% alpha-helix, 50% beta-sheet and 40% random coil. Gel filtration chromatography indicated an apparent molecular mass of 69 kDa for the refolded PHA synthase. However, light-scattering analysis of a 10-fold concentrated sample indicated a molecular mass of 128 kDa. These data suggest that the class II PHA synthase is present in an equilibrium of monomer and dimer.

Parathyroid hormone/parathyroid hormone-related peptide type 1 receptor in human bone

The parathyroid hormone/parathyroid hormone-related peptide (PTH/PTHrP) receptor (denoted as PTH-1R) is a key signaling factor through which calcium-regulating hormones PTH and PTHrP exert their effects on bone. There are contradictory reports regarding the capability of osteoclasts to express PTH-1R. To address this issue in humans, bone biopsy specimen samples from 9 normal controls and 16 patients with moderate to severe secondary renal hyperparathyroid bone disease (2 degrees HPT) with elevated PTH levels were studied to determine whether osteoclasts in the bone microenvironment express PTH-1R messenger RNA (mRNA) and protein. We report that osteoclasts express the PTH-1R mRNA but the protein is detected only in patients with 2 degrees HPT. The PTH-1R mRNA and protein also were found in osteoblasts, osteocytes, and bone marrow cells. Receptor expression was higher in osteoclasts and osteoblasts of patients with 2 degrees HPT than normal controls (98.0 +/- 1.1% vs. 65.7 +/- 14.3% and 65.8 +/- 3.4% vs. 39.1 +/- 6.2%; p < 0.01, respectively). Approximately half of osteoclasts found in bone of patients with 2 degrees HPT have the PTH-1R protein. In patients with 2 degrees HPT, a positive relationship exists between erosion depth, a parameter of osteoclastic activity, and the percentage of osteoclasts with PTH-1R protein (r = 0.58; p < 0.05). In normal controls, an inverse relationship exists between the percentage of osteoblasts with receptor mRNA, mRNA signals/cell, and serum PTH levels (r = -0.82 and p < 0.05 and r = -0.78 and p < 0.01, respectively). The results provide the novel evidence of PTH-1R in human osteoclasts and suggest a functional role for the receptors in 2 degrees HPT.

[Measurement of formaldehyde in disinfectant with spectrophotometry]

Formaldehyde in disinfectant was measured by acetylacetone spectrophotometry. The regression equation was linear when the formaldehyde concentration was smaller than 10 micrograms/ml. The detection limit was 0.08 microgram/ml. The accuracy was less than 3.9% and the recovery varied between 100.2%-108.2% for formaldehyde disinfectant with different concentration, which was similar to titrimetry. It was demonstrated that the method was simple, reproducible, sensitive, precise and accurate, making it important for assay of formaldehyde in disinfectant when disturbance caused titrimetry unavailable.

Cloning and expression of MP13 gene from rat hippocampus, a new factor related to guanosine triphosphate regulation

C-Fos and the Fos-related antigens (FRA) are induced by various stimuli. A novel 35-37 kDa FRA was induced much longer after the treatment using kainic acid (KA) and may be very important for neuronal survival after brain damage. To identify this long-term FRA, we have constructed a cDNA library derived from hippocampus after KA treatment and screened it with an antibody highly conserved M-peptide region of FRAs. One gene, MP13, was cloned with a 1662 bp open reading frame and coded for a 554-amino acid protein. MP13 has a leucine zipper region, a glutamine repeat region, and has high similarity to the activator of the small guanosine triphosphate (GTP)ase Rab5. Gel retardation analysis revealed that MP13 functions as a GTP regulation related factor.