RNA motifs that determine specificity between a viral replicase and its promoter

The 3' end of brome mosaic virus RNA contains a tRNA-like sequence that directs its RNA synthesis. A stem loop structure in this sequence, stem loop C (SLC), was investigated using NMR, and correlated with its ability to direct RNA synthesis by its replicase. SLC consists of two discrete domains, a flexible stem with an internal loop and a rigid stem containing a 5'-AUA-3' triloop. Efficient RNA synthesis requires the sequence on only one side of the flexible stem and a specific compact conformation of the triloop. A high resolution structure of the triloop places the 5' adenine out in solution, and the 3' adenine within the triloop, held tightly through stacking and unusual hydrogen bonds. This high resolution structure of an RNA promoter from a (+)-strand RNA virus provides new insights into how the RNA-dependent RNA polymerase binds to the RNA to initiate synthesis.

The CC chemokine CK beta-11/MIP-3 beta/ELC/Exodus 3 mediates tumor rejection of murine breast cancer cells through NK cells

CK beta-11 chemoattracts T cells, B cells, dendritic cells, macrophage progenitors, and NK cells and facilitates dendritic cell and T cell interactions in secondary lymphoid tissues. We hypothesized that expression of CK beta-11 in tumor cells may generate antitumor immunity through these interactions. After transduction with the retroviral vector L(CK beta 11)SN, the murine breast cancer cell line C3L5 (C3L5-CK beta 11) showed expression of retroviral mRNA by Northern analysis and production of functional CK beta-11 by chemotaxis of human NK cells to C3L5-CK beta 11 supernatant. Only 10% of mice injected with C3L5-CK beta 11 developed tumors, compared with 100% of mice injected with a transduced control C3L5 line (C3L5-G1N). Importantly, the in vitro growth characteristics of the CK beta-11-transduced cell line were unaffected, suggesting the difference in growth in vivo was a result of chemokine production. Vaccination with C3L5-CK beta 11 partially protected animals from parental C3L5 challenge. Immunodepletion with anti-asialo-GM1 or anti-CD4 during C3L5-CK beta 11 vaccination significantly reduced CK beta-11 antitumor activity compared with control and anti-CD8-treated groups. Splenocytes from NK-depleted animals transferred the acquired immunity generated with C3L5-CK beta 11 vaccination, while splenocytes from the CD4-depleted animals did not. These results indicate, for the first time, that expression of CK beta-11 in a breast cancer cell line mediates rejection of the transduced tumor through a mechanism involving NK and CD4+ cells. Furthermore, CK beta-11-transduced tumor cells generate long-term antitumor immunity that requires CD4+ cells. These studies demonstrate the potential role of CK beta-11 as an adjuvant in stimulating antitumor responses.

Impact of abnormal uptakes in bone scan on the prognosis of patients with lung cancer

The detection of bone metastases is important in the management of patients with lung cancer because bone metastasis has a major impact on the prognosis and choice of treatment modality. Bone scan has been widely used for early detection of bone metastases but its low specificity complicates confirmation of bone scan findings. To evaluate the effects of abnormal bone scan findings on the prognosis of patients with lung cancer, we retrospectively analyzed the effect of abnormal uptakes on the prognosis of patients with primary lung cancer. The overall survival of patients with abnormal bone uptake was not significantly different from those without abnormal uptake. However, the patients with more than two abnormal bone uptakes had significantly shorter survival than those with no abnormal uptake (P<0.05). To confirm the effect of abnormal bone uptakes on survival, we compared the survival curves of three patient groups without knowledge of bone scan findings: group A, stage I-IIIB with more than two abnormal bone uptakes (potential stage IV); group B, stage IIIB with no abnormal bone uptake (true stage IIIB); and group C, stage IV with no abnormal bone uptake. Group A revealed shorter survival than group B (P<0.05). But, there was no significant difference in survival times between group A and group C. In the Cox regression analysis, the presence of more than two abnormal bone uptakes was a significant prognostic factor (P=0.0277), together with performance status, stage, and albumin. These results suggest that one or two abnormal bone uptake at diagnosis did not affect overall survival of the patients, and that the patients with more than two abnormal bone uptakes are considered as clinical stage IV because of high probability of bone metastases.

Effect of a lipidic extract from lepidium meyenii on sexual behavior in mice and rats

OBJECTIVES

To determine the effect of oral administration of a purified lipidic extract from Lepidium meyenii (MacaPure M-01 and M-02) on the number of complete intromissions and mating in normal mice, and on the latent period of erection (LPE) in rats with erectile dysfunction.

METHODS

Mice and rats were randomly divided into several experimental and control groups. A 10% ethanol suspension of M-01 and M-02 was orally administered for 22 days to the experimental groups according to the dosage specified by the experimental design. On day 22, 30 minutes after the dose was administered to the male mice, 2 virgin female mice were placed with 1 male mouse. The number of complete intromissions of each male mouse in 3 hours was recorded. In an assessment of 1 day of mating, each male mouse was cohabited with 5 estrous female mice overnight. The number of sperm-positive females was recorded. The LPE was measured to assess the sexual function in rats with erectile dysfunction. By using a YSD-4G multifunction instrument, an electric pulse at 20 V was applied to stimulate the rat's penis, and the duration from the start of the stimulus to full erection was measured in seconds as the LPE.

RESULTS

In the normal male mice, the number of complete intromissions during the 3-hour period was 16.33 +/- 1.78, 46.67 +/- 2.39, and 67.01 +/- 2.55 for the control group, M-01 group, and M-02 group, respectively. In the assessment of mating, the number of sperm-positive females increased from 0.6 +/- 0.7 in the control group to 1.5 +/- 0.5 in the M-01 experimental group. The LPE of male rats with erectile dysfunction was 112 +/- 13 seconds with a regular diet (control group). The oral administration of M-01 at a dose of 180 or 1800 mg/kg body weight and M-02 at a dose of 45, 180, or 1800 mg/kg body weight reduced the LPE to 54 +/- 12 seconds, 54 +/- 13 seconds, 71 +/- 12 seconds, 73 +/- 12 seconds, and 41 +/- 13 seconds, respectively. The LPE of the surgical rats treated with M-01 at the lowest dose (45 mg/kg) was 121 +/- 12 seconds; thus, the change was not significant.

CONCLUSIONS

Oral administration of M-01 and M-02 enhanced the sexual function of the mice and rats, as evidenced by an increase in the number of complete intromissions and the number of sperm-positive females in normal mice, and a decrease in the LPE in male rats with erectile dysfunction. The present study reveals for the first time an aphrodisiac activity of L. meyenii, an Andean Mountain herb.

Refolding and purification of Zymomonas mobilis levansucrase produced as inclusion bodies in fed-batch culture of recombinant Escherichia coli

Zymomonas mobilis levansucrase was overproduced by the fed-batch culture of recombinant Escherichia coli harboring a novel expression system that is constitutively expressed by the promoter from the Rahnella aquatilis levansucrase gene. Most of the levansucrase was produced as inclusion bodies in the bacterial cytoplasm, accounting for approximately 20% of the total cellular protein. Refolding after complete denaturation by high concentrations of urea or guanidine hydrochloride was not successful, resulting in large amounts of insoluble aggregates. During the development of the refolding method, it was found that direct solubilization of the inclusion bodies with Triton X-100 reactivated the enzyme, with a considerable refolding efficiency. About 65% of inclusion body levansucrase was refolded into active levansucrase in the renaturation buffer containing 4% (v/v) Triton X-100. The in vitro refolded enzyme was purified to 95% purity by single-step DEAE-Sepharose ion exchange chromatography. Triton X-100 was removed by this ion exchange chromatography.

A tetrodotoxin-producing Vibrio strain, LM-1, from the puffer fish Fugu vermicularis radiatus

Identification of tetrodotoxin (TTX) and its derivatives produced from a Vibrio strain in the intestine of the puffer fish Fugu vermicularis radiatus was performed by thin-layer chromatography, electrophoresis, high-performance liquid chromatography, and gas chromatography-mass spectrometry, together with a mouse bioassay for toxicity. It was demonstrated that the isolated bacterium produced TTX, 4-epi-TTX, and anhTTX during cultivation, suggesting that Vibrio strains are responsible for the toxification of the puffer fish.

Relationship between endometrial estrogen and progesterone receptors, and sonographic endometrial appearance in the preovulatory phase

OBJECTIVES

The purpose of the present study is to evaluate the relationship between endometrial concentrations of estrogen receptor (ER) and progesterone receptor (PR), and sonographic endometrial findings in the preovulatory phase of menstrual cycle.

STUDY DESIGN

In 45 cycles of 45 infertile women with tubal factor only, transvaginal sonographic assessments and biopsy for immunohistochemical staining of the endometrium were made in the preovulatory phase of unstimulated, normal menstrual cycle. Immunohistochemical localization of ER and PR was scored according to intensity of staining and proportion of cells specifically stained in glandular epithelium and stroma, and the results were analysed according to the sonographic endometrial thickness (< 6 mm, 6-10 mm, or > 10 mm) and patterns. Endometrial patterns were classified as A, centrally hyperechogenic triple-line pattern or non-A, not triple-line.

RESULTS

There were no significant differences in the endometrial thickness, serum estradiol level and serum progesterone level between A and non-A groups. The receptor scores of epithelial and stromal ER and epithelial PR were comparable in A and non-A groups. However, the receptor score of stromal PR was significantly higher in A group, with 4.8 +/- 1.4 compared with 2.7 +/- 1.7 in non-A group (p < 0.001). There were no differences in the receptor scores of epithelial ER, epithelial PR, stromal ER and stromal PR among the 3 groups according to the endometrial thickness.

CONCLUSIONS

This study suggests that high PR expression in endometrial stroma could be related to the sonographic triple-line or multilayered pattern of endometrium in the preovulatory period.

Biphasic effects of dithiocarbamates on the activity of nuclear factor-kappaB

Dithiocarbamates are well-known antioxidants and nuclear factor-kappaB (NF-kappaB) inhibitors. Recently, they have been characterized as zinc ionophores. Concentration-dependent biphasic effects of dithiocarbamates on NF-kappaB activity have been widely reported. We studied the mechanism of this phenomenon in relation to Zn(2+) influx. Two dithiocarbamates, pyrrolidine dithiocarbamate and diethyldithiocarbamate, showed concentration-dependent biphasic effects in inhibiting NF-kappaB activation in cerebral endothelial cells. These unique effects of dithiocarbamates on NF-kappaB were tightly linked to their ability to elevate intracellular Zn(2+)500 microM), dithiocarbamates started to lose their ability to promote Zn(2+) influx and to inhibit NF-kappaB activation. These results might provide insight into the appropriate use of dithiocarbamates in various disorders.

Azotobacter vinelandii nitrogenases containing altered MoFe proteins with substitutions in the FeMo-cofactor environment: effects on the catalyzed reduction of acetylene and ethylene

Altered MoFe proteins of Azotobacter vinelandii Mo-nitrogenase, with amino acid substitutions in the FeMo-cofactor environment, were used to probe interactions among C(2)H(2), C(2)H(4), CO, and H(2). The altered MoFe proteins used were the alpha-195(Asn) or alpha-195(Gln) MoFe proteins, which have either asparagine or glutamine substituting for alpha-histidine-195, and the alpha-191(Lys) MoFe protein, which has lysine substituting for alpha-glutamine-191. On the basis of K(m) determinations, C(2)H(2) was a particularly poor substrate for the nitrogenase containing the alpha-191(Lys) MoFe protein. Using C(2)D(2), a correlation was shown between the stereospecificity of proton addition to give the products, cis- and trans-C(2)D(2)H(2), and the propensity of nitrogenase to produce ethane. The most extensive loss of stereospecificity occurred with nitrogenases containing either the alpha-195(Asn) or the alpha-191(Lys) MoFe proteins, which also exhibited the highest rate of ethane production from C(2)H(2). These data are consistent with the presence of a common ethylenic intermediate on the enzyme, which is responsible for both ethane production and loss of proton-addition stereochemistry. C(2)H(4) was not a substrate of the nitrogenase with the alpha-191(Lys) MoFe protein and was a poor substrate of the nitrogenases incorporating either the wild-type or the alpha-195(Gln) MoFe protein, both of which had a low V(max) and high K(m) (120 kPa). Ethylene was a somewhat better substrate for the nitrogenase with the alpha-195(Asn) MoFe protein, which exhibited a K(m) of 48 kPa and a specific activity for C(2)H(6) formation from C(2)H(4) 10-fold higher than the others. Neither the wild-type nitrogenase nor the nitrogenase containing the alpha-195(Asn) MoFe protein produced cis-C(2)D(2)H(2) when turned over under trans-C(2)D(2)H(2). These results suggest that the C(2)H(4)-reduction site is affected by substitution at residue alpha-195, although whether the effect is related to the substrate-reduction site directly or is mediated through disturbance of the delivery of electrons/protons is unclear. Ethylene inhibited total electron flux, without uncoupling MgATP hydrolysis from electron transfer, to a similar extent for all four A. vinelandii nitrogenases. This observation indicates that this C(2)H(4) flux-inhibition site is remote from the C(2)H(4)-reduction site. Added CO eliminated C(2)H(4) reduction but did not fully relieve its electron-flux inhibition with all four A. vinelandii nitrogenases, supporting the suggestion that electron-flux inhibition by C(2)H(4) is not directly connected to C(2)H(4) reduction. Thus, C(2)H(4) has two binding sites, and the presence of CO affects only the site at which it binds as a substrate. When C(2)H(2) was added, it also eliminated C(2)H(6) production from C(2)H(4) and also did not relieve electron-flux inhibition fully. Thus, C(2)H(2) and C(2)H(4) are likely reduced at the same site on the MoFe protein. Two schemes are presented to integrate the results of the interactions of C(2)H(2) and C(2)H(4) with the MoFe proteins.

Production of recombinant snakehead rhabdovirus: the NV protein is not required for viral replication

Snakehead rhabdovirus (SHRV) affects warm water fish in Southeast Asia and belongs to the genus Novirhabdovirus by virtue of its nonvirion gene (NV). Because SHRV grows best at temperatures between 28 and 31 degrees C, we were able to use the T7 expression system to produce viable recombinant SHRV from a cloned cDNA copy of the viral genome. Expression of a positive-strand RNA copy of the 11, 550-nucleotide SHRV genome along with the viral nucleocapsid (N), phosphoprotein (P), and polymerase (L) proteins resulted in the generation of infectious SHRV in cells preinfected with a vaccinia virus vector for T7 polymerase expression. Recombinant virus production was verified by detection of a unique restriction site engineered into the SHRV genome between the NV and L genes. Since we were now able to begin examining the function of the NV gene, we constructed a recombinant virus containing a nonsense mutation located 22 codons into the coding sequence of the NV protein. The NV knockout virus was produced at a concentration as high as that of wild-type virus in cultured fish cells, and the resulting virions appeared to be identical to the wild-type virions in electron micrographs. These initial studies suggest that NV has no critical function in SHRV replication in cultured fish cells.

Mx mRNA expression and RFLP analysis of rainbow trout Oncorhynchus mykiss genetic crosses selected for susceptibility or resistance to IHNV

Three interferon-inducible Mx genes have been identified in rainbow trout Oncorhynchus mykiss and their roles in virus resistance have yet to be determined. In mice, expression of the Mx1 protein is associated with resistance to influenza virus. We report a study to determine whether there was a correlation between the expression of Mx in rainbow trout and resistance to a fish rhabdovirus, infectious hematopoietic necrosis virus (IHNV). A comparison of Mx mRNA expression was made between different families of cultured rainbow trout selected for resistance or for susceptibility to IHNV. A trout-specific Mx cDNA gene probe was used to determine whether there was a correlation between Mx mRNA expression and resistance to the lethal effects of IHNV infection. Approximately 99% of trout injected with a highly virulent strain of the fish rhabdovirus, IHNV, were able to express full length Mx mRNA at 48 h post infection. This is markedly different from the expression of truncated, non-functional Mx mRNA found in most laboratory strains of mice, and the ability of only 25% of wild mice to express functional Mx protein. A restriction fragment length polymorphism (RFLP) assay was developed to compare the Mx locus between individual fish and between rainbow trout genetic crosses bred for IHNV resistance or susceptibility. The assay was able to discriminate 7 distinct RFLP patterns in the rainbow trout crosses. One cross was identified that showed a correlation between homozygosity at the Mx locus and greater susceptibility to IHN-caused mortality.

Reduced glutathione oxidation ratio and 8 ohdG accumulation by mild ischemic pretreatment

A critical role of oxidative stress has been implicated in ischemic brain damage. Mild ischemic pretreatment and/or synthesis of heat shock proteins (HSPs) has been suggested to protect against oxidative brain damage. However, experimental support of this suggestion have proven to be difficult partly because sensitive indices to assess oxidative consequences of ischemic brain damage were few. In this study, we have attempted to establish biochemical assay systems to quantitate oxidative brain damage following ischemia. We produced experimental brain ischemia in the Mongolian gerbil (Meriones unguiculatus) and examined the hippocampus for ischemic brain damage. The results obtained from ischemic gerbil hippocampus demonstrated that oxidative brain damage can be quantitated by determining glutathione oxidation ratio together with the accumulation of the oxidative DNA damage product, 8-hydroxy-2'-deoxyguanosine (8 ohdG). Our results also demonstrated a role for mild ischemic pretreatment and synthesis of HSPs against oxidative brain damage. We showed that mild 2-min ischemic pretreatment reduced the degree of both glutathione oxidation ratio and 8 ohdG accumulation in gerbil hippocampus subsequent to 10 min ischemic challenge. We also showed that the accumulation of HSP70 was closely associated with the reduction of oxidative brain damage. To our knowledge, this is the first report to investigate glutathione redox states and oxidative DNA damage levels to evaluate a protective role of mild ischemic pretreatment and HSP synthesis following brain ischemia. Our data validate the previous suggestions and provide new additional data that argue for the protective role of mild ischemic pretreatment and HSP70 synthesis against oxidative brain damage.

Expression of cyclooxygenase-1 and -2 in rheumatoid arthritis synovium

The aim of this study was to investigate the expression and localization of cyclooxygenase-1 and -2 (COX-1 and COX-2) in synovial tissues from patients with rheumatoid arthritis (RA). Synovial tissues from 9 patients with RA and 5 patients with osteoarthritis (OA) were examined for COX-1 and COX-2 expressions by immunohistochemical staining using 2 polydonal COX-1 and COX-2 antibodies. In RA synovia, synovial lining cells showed intense immunostaining for COX-1, whereas slight to moderate staining was observed in inflammatory cells, stromal fibroblast-like cells and vascular endothelial cells. There was no significant difference in COX-1 expression between RA and OA synovia. The localization of COX-2 expression dearly differed from that of COX-1 expression, being most intense in inflammatory cells. However, there was no difference in COX-1 and COX-2 expressions between RA and OA synovial tissues. Our observations support that inflammatory mechanisms modulated by COX-1 and COX-2 in chronic RA synovium might be similar to those in chronic OA synovium.

Clinical usefulness of basal FSH as a prognostic factor in patients undergoing intracytoplasmic sperm injection

OBJECTIVE

To determine if basal serum follicle stimulating hormone (FSH) level could be a prognostic factor of the clinical outcome in intracytoplasmic sperm injection (ICSI) cycles in the couples with male factor infertility.

MATERIALS AND METHODS

From December 1995 to March 1998, total 118 patients underwent in vitro fertilization and embryo transfer (IVF-ET) with ICSI due to male factor infertility were included in this study. Patients were allocated to the low basal FSH group (< 8.5 mIU/ml) and the high basal FSH group (> or = 8.5 mIU/ml). The basal levels of FSH were measured in the 3rd day of menstrual cycle preceding ovarian stimulation cycle in total IVF cycles by immunoradiometric assay (IRMA). Statistical analysis was performed using Student's t-test, Fisher's exact test, and chi 2 test as appropriate. Statistical significance was defined as p < 0.05.

RESULTS

The total dose of exogeneous gonadotropin required in the high basal FSH group was significantly higher than that in the low basal FSH group. The numbers of retrieved oocytes and oocytes with grade I, II were significantly higher in the low basal FSH group. The clinical pregnancy rate per cycle in the low basal FSH group (16.2%) was significantly higher than that in the high basal FSH group (4.0%).

CONCLUSION

These results suggested that the basal serum FSH levels could be predictive of pregnancy outcome and the results of controlled ovarian hyperstimulation (COH) in ICSI cycles.

Structural comparison of zebrafish Elav/Hu and their differential expressions during neurogenesis

The present communication reports the isolation and characterization of three new zebrafish elav/Hu (Kim, C.-H., Ueshima, E., Muraoka, O., Tanaka, H., Yeo, S.-Y., Huh, T.-L. and Miki, N., Zebrafish elav/HuC homologue as a very early neuronal marker. Neurosci. Lett., 216 (1996) 109-112) homologues, HuA, HuD and HuG. While HuA and HuG showed weak and ubiquitous expressions, HuD, as well as HuC, were specifically expressed in the neuronal cells. The first expression of HuD was detectable of the 10-somite stage, that is, several hours later than HuC. After 24 h of embryonic development, although HuD and HuC expressions overlapped overall, the cells expressing HuD were restricted to subsets of the HuC-positive neuronal cells in the brain and spinal cord. These differentially regulated spatial and temporal expression patterns implied distinct roles for HuC and HuD in neuronal determination and neuronal differentiation, respectively.

Effects of hydrochlorothiazide and furosemide diuretics on human bone marrow stromal osteoprogenitor cells

Thiazide diuretics have been shown to decrease bone loss and improve bone mineral density, while long-term furosemide therapy has been suggested to decrease bone mineral content. However, the direct effects of these diuretics on osteoblastic cells are not well established. Some investigators have reported direct effects of thiazides on osteoblastic cells but the results remain controversial, and there are few data about the direct effect of furosemide on osteoblastic cells. We investigated the effects of hydrochlorothiazide (HCTZ) and furosemide on proliferation, alkaline phosphatase activity, osteocalcin, and interleukin-6/interleukin-11 (IL-6/IL-11) secretion in cultured normal human bone marrow stromal osteoprogenitor cells (hBMSCs). Treatment with HCTZ or furosemide for 24 hours in the concentration range of 10(-6) to 10(-4) mol/L did not affect 3H-thymidine incorporation in hBMSCs. Cellular alkaline phosphatase activity and osteocalcin production were not changed significantly by treatment with HCTZ or furosemide (up to 10(-4) mol/L) during culture. There was also no significant difference in IL-6 and IL-11 production in hBMSCs. These results suggested that HCTZ or furosemide had no significant direct effect on proliferation, alkaline phosphatase activity, osteocalcin, and IL-6/IL-11 production in hBMSCs, and the effects of these diuretics on bone mass may be related to the indirect action on calcium balance.

Novel biphasic effect of pyrrolidine dithiocarbamate on neuronal cell viability is mediated by the differential regulation of intracellular zinc and copper ion levels, NF-kappaB, and MAP kinases

Nuclear factor kappaB (NF-kappaB) is a transcription factor involved in the expression of a wide range of genes, most of which code for proteins that play a role in immunity and inflammation. Pyrrolidine dithiocarbamate (PDTC) is a well-known inhibitor of NF-kappaB. Although its mechanism of action is conferred by its antioxidant property, other mechanisms by which PDTC can act as a prooxidant, metal chelator, and free thiol group modulator have recently been suggested. Here we report that PDTC caused a dual effect on cell viability in neuronal rat pheochromocytoma (PC12) cells, depending on its concentration. Increase of intracellular zinc and copper ion levels selectively potentiated the cytotoxic PDTC effect in a dose-dependent manner, and thiol reagents, such as glutathione and N-acetylcysteine, as well as divalent metal-chelating reagents, such as EDTA and bathocuproline disulfonic acid, blocked its cell death effect. The differential effect of PDTC on cell viability correlates well with the inhibition of NF-kappaB activities. In addition, PDTC differentially activated microtubule-associated protein (MAP) kinases, such as extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), but not p38, depending on its dose, and the coaddition of glutathione (GSH), other antioxidants, and metal ions also modulated their activities. Furthermore, stable Bcl-2 expression blocked the PDTC-induced cell death. These results suggest that the thiol groups and free zinc and copper ion levels are important for the novel biphasic PDTC effect on cell viability, which is associated with the differential activation of NF-kappaB and MAP kinases.

Prevalence and risk factors of low quantitative ultrasound values of calcaneus in Korean elderly women

Quantitative ultrasound (QUS) of bone is a new radiation-free, low-cost method that measures both bone mass and bone quality. This study was performed to establish the normative data of QUS for Korean women and to determine the prevalence and risk factors of low quantitative ultrasound values in a Korean elderly population. We studied 238 healthy women aged 20-29 years working at a hospital, and 552 women over 50 years of age living in six villages of Chung-Up district, a rural area of South Korea, using QUS measurement of bone. Broadband ultrasound attenuation and speed of sound were measured at the calcaneus, and an index combining these factors (stiffness index) was calculated. T-score was calculated from the data of young normal subjects. Of the 552 elderly women, 34.2% had T-scores between -1.0 and -2.5, and 11.8% had T-scores below -2.5. The prevalence of low quantitative ultrasound values increased with older age, longer duration following menopause, lower body mass index, younger age at menopause and smoking. In multiple logistic regression analysis, age (odds ratio = 1.40 per 5 years, P < 0.05), duration following menopause (odds ratio = 1.35 per 5 years, P < 0.05) and body mass index (odds ratio = 0.78 per quartile, P < 0.05) were independently associated with low quantitative ultrasound values. These results suggested that quantitative ultrasound measurement of the calcaneus could be a useful tool for epidemiological surveys of bone mass.

Suppression of endogenous insulin secretion by exogenous insulin in patients with insulinoma

OBJECTIVE

Previous studies have demonstrated that endogenous insulin secretion is not suppressed by exogenous insulin in patients with insulinoma. In this study we examined whether insulin secretion in insulinoma patients is suppressed by exogenous insulin during hypoglycaemia.

SUBJECTS AND METHODS

Sixteen insulinoma patients (5 men and 11 women) and 10 normal subjects were studied. Hyperinsulinaemic glucose clamp studies were performed at both euglycaemia (4.5 mmol/l glucose) and hypoglycaemia (2.5 mmol/l glucose).

RESULTS

In normal subjects, plasma C-peptide levels were suppressed by 66% during the euglycaemic hyperinsulinaemic clamps (P < 0.01). In contrast, in insulinoma patients, plasma C-peptide levels increased by 25% during the clamps (P < 0.05). In the hypoglycaemic hyperinsulinaemic clamps, plasma C-peptide levels were nearly completely (91%) suppressed in normal subjects and partially (39%) suppressed in patients with insulinoma (P < 0.01). The decrease in C-peptide levels during the hypoglycaemic clamps was > 30% in 12 (75%) of 16 insulinoma patients and > 50% in 8 (50%) patients.

CONCLUSIONS

This study demonstrated that in patients with insulinoma, insulin secretion was not suppressed by exogenous insulin during euglycaemia but was suppressed during hypoglycaemia, although the degree of suppression was less than that in normal subjects. Our results suggest that the feedback regulation of insulin secretion by exogenous insulin is partially retained in patients with insulinoma.

Testosterone 5 alpha-reductase inhibitors, menaquinone 7 produced by a Bacillus and phenazine methosulfate

Menaquinone 7 (MW: 649, C46H64O2), a natural electron acceptor for steroid ring A dehydrogenations, produced by Bacillus sp. SNU-299, was isolated as a rat prostate testosterone 5 alpha-reductase inhibitor with an IC50 value of 4.0 x 10(-5) M from the cultured broth. Phylloquinone was as active as the purified microbial metabolite with an IC50 value of 6.6 x 10(-4) M. On the basis of this evidence, the inhibitory activities of electron carriers, menadione, phenazine methosulfate, and 2,6-dichlorophenolindophenol, for rat prostate testosterone 5 alpha-reductase were tested, and the IC50 values were 3.1 x 10(-6) M, 4.9 x 10(-8) M, 8.9 x 10(-5) M, respectively. A product of the 5 alpha-reductase enzyme reaction and an electron and proton carrier, NADP+, inhibited the 5 alpha-reduction by rat prostate testosterone 5 alpha-reductase with an IC50 value of 9.2 x 10(-5) M. However, the inhibition effect of a proton carrier, carbonylcyanide-m-chlorophenylhydrazone, for rat prostate testosterone 5 alpha-reductase was substantially inactive.

Altered responsiveness to chemokines due to targeted disruption of SHIP

SHIP has been implicated in negative signaling in a number of hematopoietic cell types and is postulated to downregulate phosphatidylinositol-3-kinase- (PI-3K-) initiated events in diverse receptor signaling pathways. Because PI-3K is implicated in chemokine signaling, we investigated whether SHIP plays any role in cellular responses to chemokines. We found that a number of immature and mature hematopoietic cells from SHIP-deficient mice manifested enhanced directional migration (chemotaxis) in response to the chemokines stromal cell-derived factor-1 (SDF-1) and B-lymphocyte chemoattractant (BLC). SHIP(-/-) cells were also more active in calcium influx and actin polymerization in response to SDF-1. However, colony formation by SHIP-deficient hematopoietic progenitor cell (HPCs) was not inhibited by 13 myelosuppressive chemokines that normally inhibit proliferation of HPCs. These altered biologic activities of chemokines on SHIP-deficient cells are not caused by simple modulation of chemokine receptor expression in SHIP-deficient mice, implicating SHIP in the modulation of chemokine-induced signaling and downstream effects.

Improved estimates of effective dose equivalent using two optimal anisotropic responding dosimeters

Although the use of two dosimeters, one on the chest and the other on the back, successfully solved the underestimation problem for posterior incident photon beams, the two-dosimeter approach still has some problems-significant overestimations for lateral, overhead, and underfoot beam directions when isotropic-responding dosimeters are used for measurement. A solution to this problem is to intentionally construct the dosimeters to under-respond as the beam direction departs from normal incidence and approaches lateral, overhead, or underfoot beam directions. The objective of this study is to develop a dosimeter that does not significantly overestimate effective dose equivalent (H(E)) for lateral, overhead, and underfoot beam directions, while maintaining good performance for anterior and posterior beam directions. Several dosimeter geometries were investigated using Monte Carlo simulation to find the best geometry using aluminum oxide (Al2O3) as dosimeter attenuator material. Then, the developed Optimal Anisotropic Responding dosimeters were tested for 0.08, 0.30 and 1.00 MeV photon beams of various beam directions. The dosimeters did not overestimate H(E) by more than 80% considering all photon energies and beam directions, which is much less than the overestimation of isotropic-responding dosimeters (202%). The dosimeters also showed similar performance compared to isotropic-responding dosimeters for anterior and posterior beam directions. Finally, the dosimeters were applied to effective dose (E) and the results are compared with those of H(E).

Topical intrastromal steroid during laser in situ keratomileusis to retard interface keratitis

PURPOSE

To evaluate the effect of an intraoperative topical intrastromal steroid on the incidence and severity of nonspecific diffuse intralamellar keratitis (NSDIK).

SETTING

T.L.C. The Laser Center, Brea, California, USA.

METHODS

This prospective study included 2 cohort groups, each consisting of 105 consecutive eyes treated with laser in situ keratomileusis (LASIK) for myopia and astigmatism. Group A received the standard LASIK medication protocol and Group B, an additional drop of prednisolone sodium phosphate 1% solution on the undersurface of the cap immediately after it was reflected, prior to initiating the laser treatment. After the laser treatment was completed, the flap was repositioned; 1 minute after the steroid application, the interface was irrigated. All patients were examined postoperatively and placed in 1 of 4 categories: no interface keratitis, grade 1 (mild), grade 2 (moderate with decreased vision), or grade 3 (severe with decreased vision).

RESULTS

The incidence of NSDIK in Group A was 17.1% (18 eyes); 14 eyes (78.0%) were grade 1 and 4 (22.0%), grade 2. The incidence in Group B was 6.7% (7 eyes); all eyes were grade 1. Topical intrastromal steroid application significantly reduced the incidence and severity of NSDIK (P < .01).

CONCLUSION

We propose that intraoperative intrastromal steroid application is a safe and effective way to reduce the incidence and severity of NSDIK.

Metabolic effect of decreasing nonesterified fatty acid levels with acipimox in hyperthyroid patients

Glucose intolerance is often found in patients with hyperthyroidism, but the pathogenetic mechanisms are not fully understood. Since lipolysis is increased in hyperthyroidism, elevated plasma nonesterified fatty acids (NEFAs) may contribute to abnormal glucose metabolism in hyperthyroidism. The aim of this study was to investigate whether decreasing the plasma NEFA level with acipimox can affect glucose metabolism in hyperthyroidism. We performed an intravenous glucose tolerance test (IVGTT) with acipimox 250 mg or placebo in six untreated hyperthyroid men and six age- and body mass index (BMI)-matched controls. Fasting plasma NEFA levels were significantly higher in the hyperthyroid patients versus the controls (997.0 +/- 303.4 v290.5 +/- 169.1 micromol/L, P < .001). Plasma NEFAs decreased rapidly with acipimox treatment in both controls and hyperthyroid patients. In the controls, the glucose disappearance constant (K(G)) was not different for acipimox treatment versus placebo (2.18 +/- 0.62 v 2.42 +/- 1.00% x min(-1)). In hyperthyroid patients, acipimox treatment increased the K(G) significantly compared with placebo treatment (2.44 +/- 0.84 v 1.58 +/- 0.37% x min(-1), P < .05). Changes in K(G) values with acipimox treatment were inversely correlated with changes in plasma NEFA levels (r = -.65, P < .05). Acipimox treatment increased the acute insulin response (AIR) in hyperthyroid patients (943 +/- 381 v 698 +/- 279 microU/mL x min, P < .05), whereas it did not change the AIR in controls. Changes in the AIR with acipimox treatment correlated significantly with changes in the K(G) (r = .70, P < .05). There was a weak correlation between changes in the AIR with acipimox treatment and changes in plasma NEFA levels (r = -.55, P = .06). In summary, decreasing the plasma NEFA level with acipimox in hyperthyroid patients increases both the K(G) and AIR during an IVGTT. These findings suggest that the abnormal glucose metabolism in hyperthyroidism could be attributed, at least in part, to the increase of plasma NEFA.

TECK, an efficacious chemoattractant for human thymocytes, uses GPR-9-6/CCR9 as a specific receptor

Chemokines regulate leukocytes trafficking in normal and inflammation conditions. Thymus-seeding progenitors are made in bone marrow and migrate to the thymus where they undergo their maturation to antigen-specific T cells. Immature T cells are in thymic cortex, while mature thymocytes are in medulla. Chemokines may be important for homing of thymus-seeding progenitors, and/or differential thymocyte localization in thymus. Here we report that GPR-9-6, now called CC chemokine receptor 9 (CCR9), is a receptor for thymus-expressed chemokine, TECK. Among a panel of chemokines tested, TECK specifically induced calcium flux in CCR9-expressing cell lines. We also showed that TECK efficaciously induced chemotaxis of immature CD4(+)CD8(+) double-positive, and mature CD4(+) and CD8(+) single-positive human thymocytes. Our data suggest that TECK/CCR9 interaction may play a pivotal role in T-cell migration in the thymus.