C-reactive protein predicts incident fracture in community-dwelling elderly Japanese women: the Muramatsu study.

SUMMARY: In a 6-year cohort study of 751 community-dwelling elderly Japanese women, we found that C-reactive protein (CRP) is a significant predictor of osteoporotic fracture in elderly Asian women, who have significantly lower CRP levels than Caucasians. Mechanisms explaining such an association should be further studied. INTRODUCTION: While CRP, a systemic inflammation marker, is thought to be associated with osteoporosis, evidence supporting this claim has been limited. We aimed to assess the association between CRP levels and incident osteoporotic fracture in elderly women. METHODS: We conducted a cohort study with a follow-up period of 6 years. The study included 751 Japanese women aged 69 years or older. We measured serum high-sensitivity CRP (hs-CRP) levels as a major predictor. Covariates included age, body mass index, forearm bone mineral density, calcium intake, serum 25-hydroxyvitamin D, postural sway, osteoporosis medication, and physical activity. The primary outcome was incident limb and vertebral fractures. The Cox proportional hazards model was used to calculate the hazard ratio (HR) of fracture. RESULTS: Median hs-CRP values in study participants were 0.16 mg/L in the lowest tertile, 0.36 mg/L in the medium tertile, and 1.14 mg/L in the highest tertile. The hs-CRP values in these women were substantially lower than in their Caucasian counterparts. Limb or vertebral fractures occurred in 50 subjects during 4,250 person-years. Low CRP levels were associated with low incidence of limb or vertebral fractures (P for trend = 0.035). The adjusted HRs of fracture for the medium and highest quartiles of hs-CRP levels, compared to the lowest quartile, were 2.22 (95% CI, 1.02-4.84) and 2.40 (95% CI, 1.10-5.24), respectively. CONCLUSIONS: CRP is a significant predictor of osteoporotic fracture in elderly Asian women who have substantially lower CRP levels than Caucasians. Mechanisms explaining such an association should be further studied.

Vitamin D sufficiency is associated with low incidence of limb and vertebral fractures in community-dwelling elderly Japanese women: the Muramatsu Study.

UNLABELLED: Data on the association between vitamin D status and osteoporotic fracture in Asians are sparse. We conducted a 6-year cohort study of 773 community-dwelling elderly Japanese women and found that serum 25-hydroxyvitamin D (25(OH)D) ≥ 71 nmol/L was associated with a reduced risk of osteoporotic limb and vertebral fractures. INTRODUCTION: Data on the association between vitamin D status and osteoporotic fracture in Asians are sparse. This study aimed to clarify the association between vitamin D and other markers of nutritional status with the incidence of fracture in elderly Japanese women. METHODS: We conducted a cohort study with a 6-year follow-up of 773 community-dwelling women aged 69 years and older. The 6-year follow-up ended in 2009. We assessed serum 25-hydroxyvitamin D, undercarboxylated osteocalcin (an index of vitamin K status), and calcium intake. The primary outcome was incident limb and vertebral fractures. Covariates were forearm bone mineral density (BMD), age, body mass index, osteoporosis treatment, and physical activity. RESULTS: The mean serum 25(OH)D concentration was 60.0 nmol/L. Thirty-seven limb fractures and 14 vertebral fractures occurred in 4,392 person-years. Lower forearm BMD was significantly associated with increased incident fracture (P = 0.0242). The adjusted hazard ratios (HR) of fracture for the first quartile (<47.7 nmol/L) and the third quartile (59.2-70.9 nmol/L) of serum 25(OH)D, compared to the fourth quartile (≥71.0 nmol/L), were 2.82 (95% confidence interval (CI), 1.09-7.34) and 2.82 (95%CI, 1.09-7.27), respectively. The pooled adjusted HR was 0.42 (95%CI, 0.18-0.99) when the incidence in the fourth quartile (≥71.0 nmol/L) was compared to the other three quartiles combined (<71.0 nmol/L). Vitamin K status and calcium intake were not associated with incident fracture. CONCLUSIONS: Sufficient vitamin D status, i.e., serum 25(OH)D ≥ 71 nmol/L, is associated with low limb and vertebral fracture risk in community-dwelling elderly women.

Gene silencing by the tRNA maturase tRNase ZL under the direction of small-guide RNA.

We have been developing a unique system for the downregulation of a gene expression through cutting a specific mRNA by the long form of tRNA 3'-processing endoribonuclease (tRNase Z(L)) under the direction of small-guide RNA (sgRNA). However, the efficacy of this system and the involvement of tRNase Z(L) in the living cells were not clear. Here we show, by targeting the exogenous luciferase gene, that the efficacy of the sgRNA/tRNase Z(L) method can become comparable to that of the RNA interference technology and that the gene silencing is owing to tRNase Z(L) directed by sgRNA not owing to a simple antisense effect. We also show that tRNase Z(L) together with sgRNA can downregulate expression of the endogenous human genes Bcl-2 and glycogen synthase kinase-3beta by degrading their mRNAs in cell culture. Furthermore, we demonstrate that a gene expression in the livers of postnatal mice can be inhibited by an only seven-nucleotide sgRNA. These data suggest that sgRNA might be utilized as therapeutic agents to treat diseases such as cancers and AIDS.

Correlations between bone mineral density and demographic, lifestyle, and biochemical variables in community-dwelling Japanese women 69 years of age and over.

INTRODUCTION: A few epidemiologic studies have comprehensively attempted to identify risk factors for low bone mineral density (BMD) in elderly Asian women. The purpose of this study was to identify demographic, lifestyle, and biochemical factors correlated with BMD in elderly Japanese women 69 years of age and over. METHODS: The study design was cross-sectional. The subjects were 583 ambulatory women aged 69 years and over, and their average age was 74.3 (SD 4.4) years. Predictor variables were age, reproductive history, anthropometric indices, grip strength, calcium intake, lifestyle information, and serum 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D (1,25(OH)(2)D), osteocalcin (OC), and undercarboxylated osteocalcin (ucOC) values. The outcome variable was forearm BMD measured with a DTX-200 osteometer. RESULTS: Simple linear regression analyses showed that BMD was significantly positively associated with body height, weight, body mass index, grip strength, serum albumin concentration, and "housework," and negatively associated with age, years since menopause, age at menarche, number of children, serum 1,25(OH)(2)D concentration, serum OC concentration, and ucOC concentration. The stepwise multiple regression analysis showed that weight (beta=0.00316, SE=0.00028, R(2)=0.180), age (beta=-0.00321, SE=0.00050, R(2)=0.108), log-transformed serum OC (beta=-0.0445, SE=0.0064, R(2)=0.053), log-transformed serum 1,25(OH)(2)D (beta=-0.0401, SE=0.0074, R(2)=0.050), "farmwork" (beta=0.00904, SE=0.00426, R(2)=0.005), and serum 25(OH)D concentration (beta=0.000281, SE=0.000120, R(2)=0.003) were significantly associated with BMD. CONCLUSION: It was concluded that body weight is a major predictor of forearm BMD among the factors measured in this study in independent Japanese women 69 years of age and over and that serum 1,25(OH)(2)D concentration may be associated with cortical BMD. Maintenance of body weight is very important for maintaining BMD in this population, unless a large weight aggravates obesity-related diseases. A follow-up study is needed to confirm these findings.

DNA-binding activity of LndI protein and temporal expression of the gene that upregulates landomycin E production in Streptomyces globisporus 1912.

The gene lndI is involved in the pathway-specific positive regulation of biosynthesis of the antitumour polyketide landomycin E in Streptomyces globisporus 1912. LndI was overexpressed in Escherichia coli as a protein C-terminally fused to the intein-chitin-binding-domain tag and purified in a one-step column procedure. Results of in vivo LndI titration, DNA gel mobility-shift assays and promoter-probing experiments indicate that LndI is an autoregulatory DNA-binding protein that binds to its own gene promoter and to the promoter of the structural gene lndE. Enhanced green fluorescent protein was used as a reporter to study the temporal and spatial pattern of lndI transcription. Expression of lndI started before cells entered mid-exponential phase and peak expression coincided with maximal accumulation of landomycin E and biomass. In solid-phase analysis, lndI expression was evident in substrate mycelia but was absent from aerial hyphae and spores.

Hypovitaminosis D and hyperparathyroidism in physically inactive elderly Japanese living in nursing homes: relationship with age, sunlight exposure and activities of daily living.

BACKGROUND AND AIMS: The purposes of this study were to investigate the prevalences of hypovitaminosis D and hyperparathyroidism in physically inactive elderly people living in Japanese nursing homes and determine any correlations with demographic, environmental and/or life-style factors. METHODS: We targeted 220 elderly people living in nursing homes for the physically disabled in Japan. Of these, 133 (women, 113; men, 20) subjects who agreed and met our inclusion criteria were studied. The average age of the subjects was 84.6 years (SD 8.2). Serum 25-hydroxyvitamin D3 (25[OH]D3), intact parathyroid hormone (intact PTH), creatinine, and albumin concentrations were measured in each subject. Total hours of sunshine during the previous 5 weeks, activities of daily living (ADL) levels, and dietary vitamin D intake were also measured. ADL levels were evaluated using the Physical Self-Maintenance Scale (5-point scale). The examinations were performed between October and December, 1999. RESULTS: The average concentrations of serum 25(OH)D3 and intact PTH were 29.9 nmol/L (SD 13.1) and 5.04 pmol/L (SD 2.27), respectively. The prevalences of hypovitaminosis D (25[OH]D3<30 nmol/L) and hyperparathyroidism (intact PTH>6.90 pmol/L) were 77/133 (57.9%) and 21/133 (15.8%), respectively. Serum 25(OH)D3 concentrations were positively associated with hours of sunshine (R2=0.371, p<0.001) and serum albumin concentrations (R2=0.086, p<0.001), but not with age (p=0.075) or total ADL score (p=0.527). A negative association between serum intact PTH and 25(OH)D3 levels was found in subjects who were 80 years or older (p<0.001) but not in subjects under the age of 80 years. CONCLUSIONS: Hypovitaminosis D and hyperparathyroidism are commonly seen in elderly Japanese with low ADL levels. Hypovitaminosis D seems to adversely affect PTH levels, especially in the very elderly.

Low serum concentrations of 25-hydroxyvitamin D in young adult Japanese women: a cross sectional study.

OBJECTIVES: The vitamin D nutrition status of young adult women is unclear, but a recent preliminary report suggested that they may have vitamin D insufficiency. This study assessed the serum concentrations of 25-hydroxyvitamin D (25[OH]D), an index of vitamin D nutrition status, in young adult Japanese women in comparison with those in older women and investigated whether serum 25(OH)D concentrations are associated with other calcium-related hormones and bone mass. METHODS: A cross sectional study of 77 healthy women, age 19 to 66 y, working in nursing homes in Japan was conducted in the winter of 1999 and 2000. The investigation included blood tests, forearm bone mass measurements, and a lifestyle questionnaire. RESULTS: The mean serum 25(OH)D concentration in women younger than 30 y was 34.0 nmol/L (standard deviation [SD] = 11.0) and significantly lower than that in women 30 y and older (50.0 nmol/L, SD = 14.4). The proportion of subjects younger than 30 y who had serum 25(OH)D concentrations less than 30 nmol/L was 42.1% and was significantly higher (P < 0.001) than the proportion of those 30 y and older (10.3%). There was a weak but significant linear association between serum 25(OH)D concentrations and forearm bone mineral content (R(2) = 0.114, P = 0.0052) but not between serum 25(OH)D concentrations and bone mineral density. The association held after adjusting for body weight (R(2) = 0.139, P = 0.0111). Serum intact parathyroid hormone concentrations were within the normal range and not associated with serum 25(OH)D concentrations. CONCLUSIONS: Serum 25(OH)D concentrations in young adult Japanese women (<30 y old) are lower than those of older adult women (30 to 66 y), and lower serum 25(OH)D concentrations are likely associated with lower forearm bone mineral content.

Vitamin D insufficiency in Japanese female college students: a preliminary report.

Vitamin D insufficiency, a risk factor for osteoporosis, has been well investigated in elderly women worldwide, but little information has been available for younger women. This study aimed to determine serum 25-hydroxyvitamin D [25(OH)D] levels in Japanese female college students, and to test whether there is an association between 25(OH)D and bone strength. Subjects were 77 Japanese female junior college students aged 19-24 years. Serum 25(OH)D was measured with high performance liquid chromatography. Bone strength of the calcaneus was evaluated using the osteo sono-assessment index (OSI), a combined index reflecting the bone mass, bone architecture, and elasticity, as measured by quantitative ultrasound densitometry (AOS-100, Aloka). The mean 25(OH)D concentration was 34.2 nmol/L (SD +/- 12.1). The proportion of subjects with 25(OH)D less than 30 nmol/L, a cut-off value for vitamin D insufficiency, was 31/77 (40.3%). Simple linear regression analysis showed that there was a significant linear relationship between 25(OH)D and OSI (R2 = 0.098, p = 0.0069). The association held even after adjusting for weight (partial R2 = 0.098, p = 0.0023). Body weight was also a significant predictor of OSI (partial R2 = 0.105, p = 0.0034). These results suggest that vitamin D insufficiency may be prevalent in healthy young women. Moreover, low levels of 25(OH)D in young women may adversely affect bone strength. An additional, newly designed epidemiological study with a sufficient sample size is needed to confirm the present findings.

The inhibitory effect of the autoantigen La on in vitro 3' processing of mammalian precursor tRNAs.

Mammalian tRNA 3' processing endoribonuclease (3' tRNase) can remove a 3' trailer from various precursor (pre)-tRNAs. We investigated what effect the autoantigen La has on 3' processing, since the La protein is known to bind to a 3'-terminal uridine tract of pre-tRNAs. We tested sixteen different pre-tRNA(Arg) substrates containing various 3' trailers with or without a 5' leader sequence for in vitro processing by pig 3' tRNase, and for gel-retardation in the presence or absence of human La protein. The R-TUUU series consists of four pre-tRNAs containing 6, 8, 11 and 15 nt 3' trailers ending with UUU and no 5' leader, while the R-TAGC series consists of the same four pre-tRNAs as R-TUUU except that the terminal sequence is AGC. The R-6LTUUU and R-6LTAGC series are derived from R-TUUU and R-TAGC, respectively, by adding a 6 nt 5' leader. La differentially inhibited their processing and bound to the pre-tRNAs; the 50 % inhibitory concentrations for the R-TUUU, R-TAGC, R-6LTUUU, and R-6LTAGC series were 82 to >850, >850, 2 to 292 and 573 to 785 nM, respectively, and the dissociation constants were 10 to 840, >850, 3 to 203 and 155 to 520 nM, respectively. These results indicate that both the terminal sequence UUU and the 5' leader contribute to more severe inhibition of 3' processing via tighter interaction with La. With respect to the R-TUUU and R-6LTUUU series, on the whole, the La inhibition was enhanced as the 3' trailer lengths decreased. Taken together, our results suggest that the La protein sterically hinders 3' tRNase from binding a pre-tRNA molecule probably near the cleavage site.

Effective suppression of HIV-1 gene expression by a mammalian tRNA 3' processing endoribonuclease and external guide sequence oligozymes.

We examined the suppression of virus expression by cleaveage of the HIV-1 RNA gene using a mammalian tRNA 3' processing endoribonuclease and an External Guide Sequence Oligozyme (EGS) in vivo. We constructed an EGS expression vector that used the tRNA(met) promoter as an expression cassette for EGS. The EGS expression vector was targeted to the upstream region of gag, region. The EGS expression vector was co-transfected into COS cells with the HIV-1 gene plasmid vector. As compared with the EGS non-expressing cells and the EGS expressing cells, the EGS expressing cells with the targeted gag start codon had a clearly decreased amount of the HIV-1 gag p24 protein. The EGS expressing cells with the targeted gag start codon showed effective suppression of HIV-1 gene expression. Thus, these studies describe novel gene targeting agents for the inhibition of gene expression and antiviral activity.

A case of an ameloblastic fibro-odontoma arising from a calcifying odontogenic cyst.

This case report describes an ameloblastic fibro-odontoma arising from a calcifying odontogenic cyst (COC) in the mandible of a twenty-three-year old male. The patient was referred to the Department of Oral Surgery, Tokyo Dental College, on March 30th, 2000, complaining of a painful swelling, which had appeared three weeks earlier on his left mandibular molar region. In a pathological view, the lesion was a round cyst the size of a chicken-egg, dark red in color, and surrounded by a thick membrane. The cyst had an epithelium of varying thickness which included many ghost cells and an enamel-like structure on the inside, and a thick wall of connective tissue with an ameloblastic fibro-odontoma on the outside. Enamel organ-like epithelial islands were structured radially in the form of strands with immature dentin. Cytokeratin 19 was strongly immunoreactive in the epithelium of the lesion; osteopontin and osteocalcin reacted in the mesenchymal cells and weakly in the epithelial element of this tumor.

The RNA/protein symmetry hypothesis: experimental support for reverse translation of primitive proteins.

Although the "RNA-world" theory, or the RNA-first theory is renowned for a promising theory of biogenesis, it is also possible that both RNAs and proteins have coevolved forming a stable metabolic complex from the very beginning. I investigated this possibility assuming that the genetic information flowed symmetrically in the era of the origin of life, i.e. the primitive translation machinery worked in both directions (from RNA to protein and from protein to RNA). According to this RNA/protein symmetry theory, the genetic information would have come from existing cellular proteins via reverse translation. This process would have been completed in a short period of time without searching an enormous RNA sequence space. Furthermore, reverse translation would have ensured biological continuity; proteins that were essential for cellular metabolism would have been utilized in the same way as before the protein sequence information would have been transferred into the RNA sequences. I also propose a possible mechanism for the process of reverse translation. The reverse translation would proceed in the 3' to 5' direction using a set of at least 20 reverse transfer RNAs (rtRNAs) that can recognize their specific amino acid residue and carry their corresponding codon. A source of genetic information would be a primary sequence of a protein molecule. Several basic steps of reverse translation were demonstrated using rtRNA(Arg).

Are the serum 25-hydroxyvitamin D concentrations in winter associated with forearm bone mineral density in healthy elderly Japanese women?

The objective of this study was to investigate whether the serum 25-hydroxyvitamin D (25[OH]D) concentrations in winter are associated with the BMD in elderly Japanese women. The subjects were 117 healthy elderly Japanese women. Serum 25(OH)D concentrations were determined by high-performance liquid chromatography. Forearm BMD in the non-dominant arm was measured by dual-energy X-ray absorptiometry (DXA) using a DTX-200 Osteometer. The mean age of the subjects was 66.1 (SD 6.5) years (range: 46-80). The average 25(OH)D concentration was 59.1 nmol/L (SD 16.1), and five of the subjects had low 25(OH)D concentrations (< 30 nmol/L). Forearm BMD decreased linearly with age (r2 = 0.275). There was no linear association between the serum 25(OH)D concentrations and the forearm BMD (p = 0.9483). Multiple regression analysis did not reveal any association between the two (p = 0.5318) when age (p < 0.0001, r2 = 0.271) and weight (p < 0.0001, r2 = 0.153) were taken into account. Our cross-sectional study failed to reveal any association between the serum 25(OH)D concentrations and the forearm BMD in elderly Japanese women, suggesting that 25(OH)D does not play an important role in the determination of BMD. A follow-up study should be conducted to confirm the results of our cross-sectional study.

Summer/winter differences in the serum 25-hydroxyvitamin D3 and parathyroid hormone levels of Japanese women.

Serum 25-hydroxyvitamin D3 [25(OH)D3] is produced in the skin in response to exposure to ultraviolet radiation, and is a good indicator of vitamin D nutritional status. The aim of this study was to determine summer/winter differences in serum 25(OH)D3 and parathyroid hormone (PTH) in Japanese women and how the summer and winter values are related. The subjects were 122 healthy Japanese women aged 45-81 years (average age: 65.7 years). They were medically examined twice, in September 1997 and February 1999. Serum 25(OH)D3 and intact PTH were determined by high-performance liquid chromatography and a two-site immunoradiometric assay respectively. Lifestyle information was obtained through an interview. The seasonal differences (winter minus summer) in 25(OH)D3 [delta25(OH)D3] and intact PTH concentrations were -18.8 nmol/l (SD 19.2, P<0.0001) and 0.98 pmol/l (SD 1.02, P<0.0001) respectively. The correlation coefficient between summer (x) and winter (y) 25(OH)D3 levels was 0.462 (P<0.0001), with a linearly fitted line of y=0.42x+26.4. This relationship was interpreted as subjects with higher summer 25(OH)D3 values having greater reductions in winter 25(OH)D3 concentrations. There were inter-individual differences in delta25(OH)D3, although the summer and winter 25(OH)D3 concentrations were well-correlated. Since delta25(OH)D3 was not associated with any of the lifestyle factors, seasonal differences in the 25(OH)D3 concentrations of an individual appeared to reflect her ability to produce 25(OH)D3 photochemically in the skin. Sun bathing would be a less effective means of attaining adequate vitamin D nutritional status in a person with a small seasonal difference in 25(OH)D3, i.e., one with a low 25(OH)D3 level.

Serum 25-hydroxyvitamin D concentrations and related dietary factors in peri- and postmenopausal Japanese women.

BACKGROUND: Few studies of vitamin D nutrition in Asian populations have been conducted. OBJECTIVE: The objective was to assess 25-hydroxyvitamin D [25(OH)D] concentrations in healthy elderly Japanese women during the winter and to determine whether 25(OH)D concentrations are associated with lifestyle. DESIGN: We investigated 151 women aged 66.5 +/- 6.7 y (f1.gif" BORDER="0"> +/- SD) living in a rural community in February 1999. Serum 25(OH)D and intact parathyroid hormone were measured by using HPLC and an immunoradiometric assay, respectively. Information on lifestyle factors, including sunshine exposure and the consumption of vitamin D-rich foods, was also obtained through an interview. RESULTS: The mean (+/-SD) 25(OH)D concentration was 59.9 +/- 17.0 nmol/L. Vitamin D insufficiencies (<30 nmol/L) were found in 4.6% of the women, a value lower than that found in white populations. No correlation was found between age and 25(OH)D concentrations (r = 0.004, P = 0.957). The 25(OH)D concentration of subjects who consumed fish frequently (>/=4 times/wk) was 10.1 nmol/L higher (P < 0.001) than that of subjects with a moderate consumption of fish (1-3 times/wk). Additionally, those who did not consume eggs had significantly lower 25(OH)D concentrations than did those who consumed eggs >/=1 time/wk (P < 0.05). CONCLUSIONS: : The nutritional status of vitamin D in Japanese populations seems to be better than that in most Western populations. Frequent fish consumption is believed to help maintain adequate concentrations of serum 25(OH)D in elderly Japanese women during the winter.

Anomalous RNA substrates for mammalian tRNA 3' processing endoribonuclease.

Mammalian tRNA 3' processing endoribonuclease (3' tRNase) is an enzyme responsible for the removal of a 3' trailer from pre-tRNA. The enzyme can also recognize and cleave any target RNA that forms a pre-tRNA-like complex with another RNA. To investigate the interaction between 3' tRNase and substrates, we tested various anomalous pre-tRNA-like complexes for cleavage by pig 3' tRNase. We examined how base mismatches in the acceptor stem affect 3' tRNase cleavage of RNA complexes, and found that even one base mismatch in the acceptor stem drastically reduces the cleavage efficiency. Mammalian 3' tRNase was able to recognize complexes between target RNAs and 5'-half tDNAs, and cleave the target RNAs, although inefficiently, whereas the enzyme had no activity to cleave phosphodiester bonds of DNA. A relatively long RNA target, the Escherichia coli chloramphenicol acetyltransferase (CAT) mRNA, was cleaved by 3' tRNase in the presence of appropriate 5'-half tRNAs. We also demonstrated that an RNA complex of lin-4 and lin-14 from Caenorhabditis elegans can be recognized and cleaved by pig 3' tRNase.

Correct folding of a ribozyme induced by nonspecific macromolecules.

The 50-nucleotide hammerhead ribozyme HH-S was tested for self-cleavage. The self-cleavage was very inefficient, and only 13% of HH-S was transformed to its cleavage products. Surprisingly, the percentage of cleavage of HH-S was increased to 30% when 1 microg of tRNA was added to the reaction mixture (6 microL). Other macromolecules such as DNAs and proteins were examined to see if they also augmented cleavage of HH-S, and it was found that most of the macromolecules tested, except nucleotide monomers, did indeed enhance HH-S cleavage. The self-cleaving reaction was almost saturated in 30 min, and only 13% of HH-S was cleaved at 37 degrees C for a 70-min reaction, indicating that 87% of HH-S was in kinetically trapped inactive conformations. Time courses for the reaction of the HH-S self-cleavage were also measured in the presence of tRNA, an oligodeoxyribonucleotide, or BSA. Cleavage of HH-S, which had already reached a plateau of 13% cleaved, increased gradually after the addition of the effector molecules. The first-order rate constant for the self-cleavage reaction in the absence of an effector was comparable to that in the presence of BSA, indicating that the effector molecules do not affect the chemical step of self-cleavage. These results demonstrate that a variety of nonspecific macromolecules can induce conformational change of the hammerhead even in such a low concentration as 0.003% (w/v). This conformational change may occur by macromolecular collisions, or nonspecific weak interactions between HH-S and effectors. Alternatively, a molecular crowding effect may cause the conformational change.

Age and sex differences in the bone mineral density of the distal forearm based on health check-up data of 6343 Japanese.

Bone mineral density (BMD) predicts osteoporotic fractures. The incidence of osteoporotic fractures in Japan is lower than among Caucasians, but fewer data on the BMD of Asians have been reported. This study attempted to clarify the age and sex differences in the forearm BMD of healthy adult Japanese and to assess racial differences between Japanese and Caucasians. The subjects were 6343 healthy adult Japanese (5281 females, 1062 males) who underwent a health check-up at a health care service center between February 1995 and August 1999. Subjects' age ranged from 15 to 80 years. The BMD of the distal radius and ulna of the non dominant forearm was measured by dual-energy X-ray absorptiometry. Overall, the forearm BMD of men was greater than that of women in all age groups. Peak BMD was 0.484 g/cm2 in the 40-44 year age group of women and 0.590 g/cm2 in the 30-34 year age group of men. The forearm BMD of women under 50 years of age (the average age at menopause) increased slightly with age (2.0%/decade, p < 0.0001), but it did not among their male counterparts. After 50 years of age, BMD of the women decreased linearly (-1.6%/year, p < 0.0001) with age, the rate of decrease being 1.7-fold faster than in their male counterparts. Rates of gain and loss of forearm BMD differ between the sexes. In comparison with data previously reported, we did not find any evidence of racial differences in BMD as an explanation for the lower incidence of osteoporotic fractures in Japan.

Serum parathyroid hormone in healthy Japanese women in relation to serum 25-hydroxyvitamin D.

The aim of this work was to clarify levels of serum parathyroid hormone (PTH) in healthy adult women and to study the relationship between PTH and 25-hydroxyvitamin D [25(OH)D]. One hundred sixty-nine healthy women aged 40 years or older in a community were studied. The average age of the subjects was 65.3 years (SD 8.2). All subjects had normal serum creatinine levels. Serum intact PTH and 25(OH)D were measured in these subjects. The mean intact PTH concentration was 2.19 pmol/l (SD 1.02). High intact PTH levels above the reference range were observed in four women (2.4%), all of whom were aged 70 years or older. Intact PTH increased with age with a correlation coefficient of 0.192 (p = 0.013). However, there was no correlation (r = -0.125, p = 0.105) between intact PTH and 25(OH)D whose concentrations were more than 37.5 nmol/l. In conclusion, PTH levels of healthy adult Japanese women are lower than previous reports from Western countries, which may be due to the high 25(OH)D levels of the present subjects and/or an ethnic difference. In addition, there is no association between serum 25(OH)D and PTH levels in this Japanese population, supporting a cutoff level of 25(OH)D less than 37.5 nmol/l for the elevated PTH level.

Effective suppression of HIV-1 gene expression by a mammalian tRNA 3' processing endoribonuclease and external guide sequence oligozymes.

We examined the suppression of virus expression by cleavage of the HIV-1 RNA gene using a mammalian tRNA 3' processing endoribonuclease and an External Guide Sequence Oligozyme (EGS) in vivo. We constructed an EGS expression vector that used the tRNA(met) promoter as an expression cassette for EGS. The EGS expression vector was targeted to the upstream region of gag, region. The EGS expression vector was co-transfected into COS cells with the HIV-1 gene plasmid vector. As compared with the EGS non-expressing cells and the EGS expressing cells, the EGS expressing cells with the targeted gag start codon had a clearly decreased amount of the HIV-1 gag p24 protein. The EGS expressing cells with the targeted gag start codon showed effective suppression of HIV-1 gene expression. Thus, these studies describe novel gene targeting agents for the inhibition of gene expression and antiviral activity.