Baseline and changes in serum uric acid independently predict 11-year incidence of metabolic syndrome among community-dwelling women.

INTRODUCTION: Metabolic syndrome (MetS) is associated with an increased risk of major cardiovascular events. In women, increased serum uric acid (SUA) levels are associated with MetS and its components. However, whether baseline and changes in SUA predict incidence of MetS and its components remains unclear. METHODS: The subjects comprised 407 women aged 71 ± 8 years from a rural village. We have identified participants who underwent a similar examination 11 years ago, and examined the relationship between baseline and changes in SUA, and MetS based on the modified criteria of the National Cholesterol Education Program's Adult Treatment Panel (NCEP-ATP) III report. RESULTS: Of these subjects, 83 (20.4%) women at baseline and 190 (46.7%) women at follow-up had MetS. Multiple linear regression analysis was performed to evaluate the contribution of each confounding factor for MetS; both baseline and changes in SUA as well as history of cardiovascular disease, low-density lipoprotein cholesterol, and estimated glomerular filtration ratio (eGFR) were independently and significantly associated with the number of MetS components during an 11-year follow-up. The adjusted odds ratios (ORs) (95% confidence interval) for incident MetS across tertiles of baseline SUA and changes in SUA were 1.00, 1.47 (0.82-2.65), and 3.11 (1.66-5.83), and 1.00, 1.88 (1.03-3.40), and 2.49 (1.38-4.47), respectively. In addition, the combined effect between increased baseline and changes in SUA was also a significant and independent determinant for the accumulation of MetS components (F = 20.29, p < 0.001). The ORs for incident MetS were significant only in subjects with age ≥ 55 years, decline in eGFR, and no baseline MetS. CONCLUSIONS: These results suggested that combined assessment of baseline and changes in SUA levels provides increased information for incident MetS, independent of other confounding factors in community-dwelling women.

Interaction between gender and uric acid on hemoglobin A1c in community-dwelling persons.

INTRODUCTION: Higher glycated hemoglobin (Hb) (HbA1c) is significantly associated with an increased risk of cardiovascular disease (CVD). Serum uric acid (SUA) levels are associated with glucose intolerance and type 2 diabetes. Whether gender-specific differences regarding the relationship between SUA levels and HbA1c exist is unknown. AIM: We recruited 1636 (men, 696 aged of 70 ± 10 years; women, 940 aged of 70 ± 9 years) participants and enrolled in the study during their annual health examination from a single community. We investigated the association between SUA levels and HbA1c within each gender. RESULTS: Multiple linear regression analysis showed that in men, SUA (ß = -0.091, p = 0.014) with prevalence of antidiabetic medication (ß = 0.428, p < 0.001) and eGFR (ß = 0.112, p = 0.016) were significantly and negatively associated with HbA1c, and in women, SUA (ß = 0.101, p = 0.002) with prevalence of antidiabetic medication (ß = 0.458, p < 0.001) were significantly and positively associated with HbA1c. Moreover, the interaction between gender and SUA (ß = 0.445, p < 0.001) as well as gender (ß = -0.465, p < 0.001), prevalence of antidiabetic medication (ß = 0.444, p < 0.001), eGFRCKDEPI (ß = 0.074, p = 0.014), and SUA (ß = -0.356, p < 0.001) was a significant and independent determinant of HbA1c. A significant interactive effect of gender and SUA on determinants of HbA1c was noted in patients not on antidiabetic medications, regardless of age, HbA1c, and renal function. CONCLUSIONS: The interaction between gender and SUA was associated with HbA1c independent of other metabolic factors in community-dwelling persons.

Induction of bud formation of embryonic mouse tracheal epithelium by fibroblast growth factor plus transferrin in mesenchyme-free culture.

Embryonic mouse tracheal epithelium, which branches in an epithelial-mesenchymal recombination culture with bronchial mesenchyme, was cultured under mesenchyme-free conditions. When embedded in a basement-membrane-like matrix and cultured in a serum-free medium supplemented with fibroblast growth factor 1 (FGF1), the tracheal epithelium did not branch, whereas the bronchial epithelium underwent branching morphogenesis. When the medium was enriched with transferrin (Tf), bud formation was induced in the tracheal epithelium and some buds branched secondarily. FGF7 and FGF10, in cooperation with Tf, induced tracheal bud formation to the same extent as FGF1, although the optimum concentrations differed. A bromodeoxyuridine-labeling study comparing cultures with and without Tf showed no Tf-specific amplification of cell proliferation. A whole-mount in situ hybridization study of the expression of Bmp4 and Shh genes in explants of mesenchyme-free culture revealed that both genes were ubiquitously expressed and that expression did not correlate with bud formation. This expression pattern was different from the distally localized expression pattern observed in normal lung rudiments and in extratracheal buds induced by the recombined bronchial mesenchyme. These results suggest that both bronchial and tracheal bud formations were initiated without localized exposure of the epithelium to FGFs and were not accompanied by localized expression of Bmp4 and Shh in the epithelium.

[Two cases of Chlamydia psittaci infection occurring in employees of the same pet shop].

We report here 2 cases of psittacosis in a pet shop. In the first case, a 44-year-old male was admitted with fever, and a chest radiograph showed an infiltration shadow in the right lower lung. One day later, a colleague of the first patient, a 42-year-old man, developed fever and was admitted. In this patient, chest radiography revealed an infiltration shadow in the left lower lung. Both patients had mild liver dysfunction. The serum titer of a complement fixation (CF) test against Chlamydia psittaci was elevated fourfold in the first case and sixteen-fold in the second on the analysis of paired acute- and convalescent-phase serum specimens. Clinical symptoms and abnormal laboratory data were attenuated by the administration of minocycline for 2 weeks. Since both patients worked in same pet shop and since some parakeets at the shop had died, we speculated that the psittacosis had originated from these birds.

[Diagnostic imaging of osteoporosis: special reference to diagnosis by radiography and DXA].

Primary osteoporosis is diagnosed by diagnostic criteria, eg. whether non-traumatic vertebral body is or not, or the severity of low bone mass. As a diagnostic imaging of osteoporosis, grading of radiographic osteopenia, and Singh index in the upper end of femur are well-known. Vertebral fracture associated with osteoporosis shows wedge, fish or flat deformity, but it is necessary to differentiate from Schmorl node and so on. DXA is a main stream of bone mineral quantification method, and its image is expressed the distribution of bone mineral density per unit area.

Isolation and characterization of murine coronavirus mutants resistant to neutralization by soluble receptors.

Murine coronavirus mutants resistant to neutralization with soluble receptors were isolated to study the receptor-binding site on the S proteins since such mutants were expected to have mutations in an important site for receptor-binding. We have isolated five soluble receptor-resistant (srr) mutants which had mutations of a single amino acid at 3 different positions in S protein. Srr mutant 11 with an amino acid change at position 65 (Leu to His) in the S1 subunit showed an extremely reduced binding by virus overlay protein blot assay. However srr mutants with a mutation at 1114 (Leu to Phe) (srr mutants 3, 4 and 7) or 1163 (Cys to Phe) (srr mutant 18) in the S2 subunit had receptor-binding activity similar to that of wild type cl-2. These results suggest that an amino acid at position 62 located in a conserved region among MHV strains is in particular important for receptor binding. We also discuss why srr mutants with a mutation in S2 showed high resistance to neutralization by soluble receptor, irrespective of their binding to MHV receptors.

Differential receptor-functionality of the two distinct receptor proteins for mouse hepatitis virus.

We compared the virus-binding activity and receptor-functionality of the receptor proteins isolated from mouse hepatitis virus (MHV)-susceptible BALB/c mice (MHVR1) and MHV-resistant SJL mice (MHVR2). By using a soluble receptor protein which lacked the transmembrane and intracytoplasmic domains, virus overlay protein blot assay and neutralization tests showed that MHVR1 bound to JHM cl-2 virus with 300-500 times higher efficiency than to MHVR2. MHVR1 was revealed to have 10-30 fold higher receptor-functionality than MHVR2 when examined by measuring virus-binding to the receptor expressed on the cell surface. These findings suggested that the differences in susceptibility between BALB/c and SJL mice may depend upon the genotype of the MHV receptor.

Identification of spike protein residues of murine coronavirus responsible for receptor-binding activity by use of soluble receptor-resistant mutants.

We previously demonstrated by site-directed mutagenesis analysis that the amino acid residues at positions 62 and 214 to 216 in the N-terminal region of mouse hepatitis virus (MHV) spike (S) protein are important for receptor-binding activity (H. Suzuki and F. Taguchi, J. Virol. 70:2632-2636, 1996). To further identify the residues responsible for the activity, we isolated the mutant viruses that were not neutralized with the soluble form of MHV receptor proteins, since such mutants were expected to have mutations in amino acids responsible for receptor-binding activity. Five soluble-receptor-resistant (srr) mutants isolated had mutations in a single amino acid at three different positions: one was at position 65 (Leu to His) (srr11) in the S1 subunit and three were at position 1114 (Leu to Phe) (srr3, srr4, and srr7) and one was at position 1163 (Cys to Phe) (srr18) in the S2 subunit. The receptor-binding activity examined by a virus overlay protein blot assay and by a coimmunoprecipitation assay showed that srr11 S protein had extremely reduced binding activity, while the srr7 and srr18 proteins had binding activity similar to that of wild-type cl-2 protein. However, when cell surface receptors were used for the binding assay, all srr mutants showed activity similar to that of the wild type or only slightly reduced activity. These results, together with our previous observations, suggest that amino acids located at positions 62 to 65 of S1, a region conserved among the MHV strains examined, are important for receptor-binding activity. We also discuss the mechanism by which srr mutants with a mutation in S2 showed high resistance to neutralization by a soluble receptor, despite their sufficient level of binding to soluble receptors.

Mouse susceptibility to mouse hepatitis virus infection is linked to viral receptor genotype.

We have reported that the receptor for mouse hepatitis virus (MHV) expressed in MHV-susceptible BALB/c mice (MHVR1) has 10 to 30 times the virus-binding activity of the MHV receptor expressed in MHV-resistant SJL mice (MHVR2) (N. Ohtsuka, Y. K. Yamada, and F. Taguchi, J. Gen. Virol. 77:1683-1992, 1996). This fact indicates the possibility that the difference in MHV susceptibility between BALB/c and SJL mice is determined by the virus-binding activity of the receptor. To test this possibility, we have examined MHV susceptibility in mice with the homozygous MHVR1 gene (R1/R1 genotype), mice with the MHVR1 and MHVR2 genes (R1/R2 genotype), and mice with the homozygous MHVR2 gene (R2/R2 genotype) produced by cross and backcross mating between BALB/c and SJL mice. All 63 F2 and backcrossed mice with the MHVR1 gene (R1/R1 and R1/R2) were susceptible to MHV infection, and all 57 with the homozygous MHVR2 gene (R2/R2) were resistant. We have also examined the MHV receptor genotypes of several mouse strains that were reported to be susceptible to MHV infection. All of those mice had the MHVR1 gene. These results suggest the possibility that the viral receptor determines the susceptibility of the whole animal to MHV infection.

Testosterone does not eliminate the attenuating effect of estrogen on progressive glomerular injury in estrogen-treated hypercholesterolemic male Imai rats.

Hypercholesterolemic Imai rats spontaneously develop proteinuria and glomerulosclerosis, especially males. Estrogen attenuates the progressive glomerular injury in these male rats. To clarify whether this attenuating effect of estrogen depends on a reduction of testosterone and/or a reduction of the sex-related factors, we investigated whether testosterone administration eliminates the attenuating effect of estrogen on the development of glomerular injury in estrogen-treated male Imai rats. Estrogen significantly reduced sex-related low molecular weight protein excretion to undetectable levels; and treatment with estrogen and testosterone failed to increase these levels. Unexpectedly, treatment with estrogen and testosterone attenuated glomerular injury more than treatment with estrogen only. Estrogen significantly increased both levels of estrogen and growth hormone (GH), whereas it suppressed testosterone levels. Testosterone administration resulted in an increase in serum testosterone levels of about fivefold above the control levels, but reduced the elevated serum GH to the levels of the controls. These results suggest that estrogen appears to play a protective role by itself or in association with sex-related factors, independent of the levels of serum testosterone, and that testosterone does not exert its effect on augmenting glomerular injury and rather may act to attenuate glomerular injury associated with a reduction of GH levels.

The ovaries attenuate the aggravating effect of testosterone on glomerular injury in Adriamycin-induced nephropathy of female rats.

To clarify whether the ovaries have a potential to attenuate the aggravating effect of testosterone (T) on glomerular injury, we investigated the effect of T in female rats with or without ovaries, using Adriamycin (ADR)-induced nephropathy in female Sprague-Dawley rats. Group 1 consisted of female control rats, group 2 received T, groups 3 and 4 were subjected to ovariectomy (OVX) at 5 weeks of age, and group 4 received further T treatment. Group 5 consisted of male control rats. T was injected subcutaneously every 4 weeks from 5 weeks of age through the end of the experiment. ADR 2 mg/kg was administered intravenously to all rats twice, at 8 weeks of age and 20 days later. Body weight, blood pressure, urinary protein and serum constituents were investigated every 4 weeks from 4 through 24 weeks after the second ADR injection. Each group was studied morphologically 24 weeks after the second ADR injection. Treatment with T or with OVX and T significantly increased the urinary protein excretion. OVX had no significant effect on the urinary protein excretion. Treatment with either T or OVX did not induce any significant effects on the renal function with regard to blood urea nitrogen (BUN), serum creatinine (Cr) and Cr clearance (Ccr) levels, but a combined treatment with OVX and T significantly lowered the serum albumin levels, increased the levels of BUN and Cr and lowered the Ccr values. The glomerulosclerosis index was significantly and markedly higher in control male rats than in control females. Treatment with T resulted in a slight but significant increase in glomerular injury to levels similar to those seen in ovariectomized rats. Combined treatment with OVX and T significantly aggravated glomerular injury in a somewhat accelerated manner, associated with a significant increase in glomerular tuft volume. Our results suggested that the ovaries could not completely suppress glomerular injury worsened by T administered at serum levels similar to those of male rats, but they had a potential to attenuate glomerular injury induced by T, and the protective effect of the ovaries on glomerular injury may be related to their attenuating effect on glomerular growth.

Different effect of estrogen administration from castration on glomerular injury in unilaterally nephrectomized male Sprague-Dawley rats.

We have already reported an equally attenuating effect of castration or estrogen administration on the development of focal segmental glomerulosclerosis (FSGS) in the animal models of a short-term experimental period ended at 24 weeks. In the present study, to clarify the importance of the experimental period in studying the pathogenesis of the development of FSGS, we investigated a long-term effect of castration or estrogen administration on FSGS using an experimental model of uninephrectomized Sprague-Dawley (SD) rats ended at 54 weeks. Thirty male SD rats received unilaterally right nephrectomy at 6 weeks of age. They were divided into three groups: group 1 was control; group 2 was castrated at 6 weeks, and group 3 was administered 0.2 mg estrogen subcutaneously once a month from 6 weeks of age. Body weight, urinary protein, serum albumin and other serum constituents were investigated every 12 weeks from 18 to 54 weeks of age. Each group was studied morphologically at the end of the experiment. Castration attenuated glomerular injury to the same extent as seen in the study of a short-term experimental period, while estrogen administration failed to attenuate glomerular injury, although each treatment equally suppressed an urinary excretion of a sex-related low-molecular-weight (LMW) protein. Castration reduced significantly kidney weight (KW), glomerular volume (GV) and serum growth hormone (GH) levels, but estrogen treatment failed to reduce KW and GV, and conversely elevated GH levels. These results suggest that a sex-related LMW protein influenced by castration or estrogen treatment may not play an important role in the development of FSGS and that an increase in plasma GH levels may contribute to the failure of an attenuating effect of estrogen on glomerular injury.

Attenuating effect of castration on glomerular injury is age-dependent in unilaterally nephrectomized male Sprague-Dawley rats.

To clarify a role of sex hormones in greater susceptibility of young rats than adults to the development of focal and segmental glomerulosclerosis (FSGS), we castrated animals at different ages and investigated whether the attenuating effect of castration on FSGS is age-dependent in unilaterally nephrectomized male Sprague-Dawley (SD) rats. At 6 weeks of age, all groups received unilateral right nephrectomy (Nx) and group 2 was simultaneously castrated, while group 1 received a sham operation. Group 3 was castrated at 3 months of age, and group 4 at 6 months of age. Body weight, blood pressure, urinary protein and serum constituents were investigated every 2 months from 4 to 14 months of age. At 6 and 14 months of age, rats were studied morphologically. Castration at 6 weeks of age or at 3 months of age significantly inhibited the compensatory glomerular hypertrophy and hyperfunction with regard to the creatinine clearance as seen in Nx rats at 6 months of age and significantly reduced glomerular injury at the end of the experiment, while castration at 6 months produced neither an inhibitory effect on glomerular hypertrophy nor an attenuating effect on glomerular injury. Serum levels of growth hormone (GH) and somatomedin-C (SmC) were decreased by castration to a greater extent when castrated at younger age. These findings indicated that GH and SmC influenced by male sex hormone seem to play a more important role at younger age than in adults in exerting its effect on glomerular growth, leading somehow to glomerular injury in aging, unilaterally nephrectomized male SD rats.

Difference in virus-binding activity of two distinct receptor proteins for mouse hepatitis virus.

The receptor proteins, MHVR1 (Bgp C or splice variant of mmCGM1 containing two ectodomains) and MHVR2 (mmCGM2) have been reported to be functional receptors for MHV, although there was a significant difference in their virus-binding activity as determined by virus overlay protein blot assay (VOPBA). To compare the receptor function of these proteins, their virus-binding capacities were tested by using soluble forms of the proteins which lacked the transmembrane and intracytoplasmic domains. To estimate the amounts of these proteins expressed, an epitope of influenza HA protein, for which specific monoclonal antibody was available, was used as a tag. Recombinant soluble MHVR1 and MHVR2, expressed in RK 13 cells using recombinant vaccinia virus were secreted into the culture fluids of infected cells expressing these proteins. The inhibitory effect on virus infectivity of MHVR1 was shown to be about 500-fold higher than that of MHVR2. A similar disparity was observed in virus binding by VOPBA. These two proteins worked as functional receptors when they were expressed on resistant BHK-21 cells. However, the efficiency of MHV infection in BHK-21 cells expressing MHVR1 was about 30-fold higher, as compared with those expressing MHVR2. These data show that the receptor function of MHVR1 was significantly higher than that of MHVR2 and suggests that the difference in susceptibility between SJL and BALB/c mice might be due to the specific receptor protein expressed in those animals.

Ovariectomy attenuates proteinuria and glomerular injury in unilaterally nephrectomized female Sprague-Dawley rats.

To determine the contribution of the ovary to the development of glomerulo-sclerosis, we investigated the effect of ovariectomy on glomerulosclerosis, using the unilaterally nephrectomized (Nx) female Sprague-Dawley rat. At 6 weeks of age, groups 2 and 3 underwent unilateral right nephrectomy and group 3 was simultaneously ovariectomized, while group 1 underwent a sham operation. Body weight, blood pressure, urinary protein, serum albumin, cholesterol, blood urea nitrogen and serum creatinine were checked every 2 months from 2 to 12 months after right nephrectomy. Control group 1, the Nx group 2 and the ovariectomized (Nx + ovariectomized) group 3 were studied morphologically at 6 and 12 months after nephrectomy. Body weight significantly increased in ovariectomized rats as compared with control and Nx rats. Nx rats became proteinuric with age. Ovariectomy significantly reduced proteinuria to the same levels in the controls. The glomerulosclerosis index was significantly higher in Nx rats than in either controls or ovariectomized rats. Ovariectomy attenuated glomerular injury in Nx rats, though not to the same levels in the control rats. Three groups showed no significant differences in either blood pressure or plasma somatomedin C. Growth hormone (GH) was significantly decreased by ovariectomy. The severity of glomerular injury and the glomerular tuft volume correlated with GH levels. Our results suggested that a decrease in plasma GH may contribute to the attenuating effect of ovariectomy on the development of glomerular injury in aging unilaterally Nx female Sprague-Dawley rats.

Effect of ovariectomy on glomerular injury in hypercholesterolemic female Imai rats.

To clarify the pathogenesis of focal and segmental glomerulosclerosis, we investigated the effect of ovariectomy in hypercholesterolemic female Imai rats. At 5 weeks of age, control female (group 1) and control male rats (group 3) were sham-operated, female rats (group 2) were ovariectomized and male rats (group 4) were castrated. Body weight, blood pressure, urinary protein and serum constituents were checked every 2 months from 2 through 12 months of age. All groups were studied morphologically at 6 months of age and further female groups (1 and 2) studied at 12 months. Both control female and control male rats developed marked proteinuria, to a significantly greater extent in the male rats. Castration reduced proteinuria, while ovariectomy did not influence it and there were no significant differences in proteinuria among the control females, the ovariectomized females and the castrated males. Control male rats had significantly lower serum albumin levels, higher cholesterol levels and a significantly greater impairment of renal function in blood urea nitrogen (BUN) levels than did the control female rats at 6 months. Castration significantly increased serum albumin levels and lowered BUN levels, while ovariectomy did not basically influence these values in the female rats. The glomerulosclerosis index at 6 months of age was significantly higher in the control males than in the control females. Castration attenuated glomerular injury, while ovariectomy aggravated glomerular injury to the same levels as found in the castrated males. This aggravating effect of ovariectomy observed at 6 months, however, disappeared at 12 months. These results suggested that sex-related factors regulated by the ovaries may play an inhibitory role in the development of glomerulosclerosis before 6 months of age, but not thereafter, in hypercholesterolemic female Imai rats.

Sex difference in progression of adriamycin-induced nephropathy in rats.

To clarify the pathogenesis of focal-segmental glomerulosclerosis, we investigated the sex-related difference and the effect of castration in Adriamycin (ADR) induced nephropathy of Sprague-Dawley rats. At 5 weeks of age, group 1 female and group 2 male rats were sham operated, and group 3 male rats were castrated. ADR 2 mg/kg was intravenously administered to all rats at 8 weeks of age twice at a 20-day interval. Body weight, blood pressure, urinary protein, and serum constituents were investigated every 4 weeks, 4-20 weeks after the second ADR injection. Each group was studied morphologically 12 and 20 weeks after the second ADR injection. ADR induced massive proteinuria in male rats, whereas it induced significantly lower proteinuria in female rats, and castration significantly reduced proteinuria of male rats to an extent equal to the levels seen in female rats. Control male rats had significantly lower serum albumin levels and a significantly greater impairment of renal function (blood urea nitrogen and creatinine levels) than the female rats or the castrated male rats at 20 weeks. The glomerulosclerosis index was significantly higher in control male rats than in female rats, and castration attenuated glomerular injury of male rats to an extent close to the levels seen in female rats, though there was a significant difference in the glomerulosclerosis index between female rats and castrated male rats. The three groups did not differ in blood pressure and plasma somatomedin C and serum growth hormone levels, whereas the plasma testosterone levels were decreased to undetectable in female and castrated male rats, resulting in a reduction of sex-related low molecular weight protein in urine. These observations suggest that sex hormones such as testosterone and estrogen and/or sex-related low molecular weight protein regulated by testosterone and estrogen may play a contributory role in sex differences in the progression of glomerulosclerosis in ADR-treated rats.