Biotin influences palatal development of mouse embryos in organ culture

Maternal biotin deficiency is strongly teratogenic in CD-1 mice. The most common malformations are craniofacial and limb defects such as cleft palate, micrognathia and micromelia. The effect of biotin deficiency on palatal development in mouse embryos on d 12 of gestation was studied by culturing mouse embryonic palates in serum-free medium using a suspension culture system. In control embryos palatal processes developed to the fused stage after 72 h in culture. The fusion of palatal processes was further increased by the addition of biotin (10(-8) mol/L) to the medium. The addition of organic acids such as propionic, beta-methyl crotonic or beta-hydroxy isovaleric acids as well as avidin to the medium did not affect the stage of palatal formation. Cycloheximide completely blocked the fusion of palatal shelves. In embryos from biotin-deficient mice, the incidence of fusion between the palatal shelves was < 7% and increased to > 30% when biotin (10(-8)-10(-6) mol/L) was added to the medium. The addition of fatty acids to the organ culture medium did not have any effect on the fusion of palatal processes. The incorporation of 35S-methionine into protein from biotin-deficient embryo explants was 88% of that in controls. The results indicate that biotin deficiency may interfere directly with synthesis of specific proteins and the formation of palatal processes.

Functional role of coronary collaterals with exercise in infarct-related myocardium

We evaluated the regional myocardial blood flow in collateral dependent infarct-related areas to examine the functional role of coronary collaterals. Regional myocardial blood flow was measured by positron emission tomography with 13N-ammonia at rest and during low-grade exercise (bicycle ergometer fixed at 25 W for 6.5 min). The study was performed in 24 subjects, consisting of 19 patients with prior myocardial infarction, and five normal individuals. Regional myocardial blood flow was calculated using the radioactivity in myocardial tissue measured by positron emission tomography and the radioactivity in arterial blood. Concerning the infarct related area, the exercise caused myocardial blood flow to decrease by 18.4% (P < 0.01) in the collateral-dependent areas (n = 8) of angiographically positive collaterals, and to increase by 14.4% (P = not significant) in the areas (n = 10) of negative collaterals. Four patients in whom the myocardial blood flow in all walls, including the normal areas, decreased with exercise were excluded from this evaluation. Myocardial blood flow in collateral-dependent infarct-related areas appeared to decrease transiently by low-grade exercise. Our results suggest that collaterals increase the incidence of exercise-induced ischemia, but may protect the infarct related but viable myocardium from necrosis.

Immunocytochemical colocalizations of serotonin, aromatic L-amino acid decarboxylase and polypeptide hormones in A- and PP-cells of the chicken endocrine pancreas

The colocalization of serotonin and aromatic L-amino acid decarboxylase (AADC) in the avian pancreatic polypeptide-containing PP-cells and glucagon-storing A-cells of the chicken endocrine pancreas was investigated using combined pre-embedding immuno-peroxidase and post-embedding immunogold electron microscopic immunocytochemistry. The avian pancreatic polypeptide-immunoreactive cells manifested by the labeling of immunogold particles on secretory granules were also immunoreactive with antisera directed against serotonin and AADC, an enzyme involved in the synthesis of serotonin. In PP-cells immunoreactivity against the anti-serotonin serum was stronger in secretory granules than in the cytoplasmic matrix, whereas immunoreaction with the anti-AADC serum was observed to be more intense in the cytoplasmic matrix. Immunoreactions with the serotonin and AADC antisera were also found in secretory granules of glucagon-storing A-cells. These results indicate that serotonin is co-stored within secretory granules of both A- and PP-cells, and that AADC is localized within secretory granules of A-cells, and may be present in the cytoplasmic matrix of PP-cells. It is probable that serotonin is synthesized and released simultaneously with secretory granules from both A- and PP-cells of the chicken endocrine pancreas.

Identification of two human sequence-specific DNA-binding proteins which interact with the direct repeats in the squirrel monkey retrovirus long terminal repeat

Squirrel monkey retrovirus (SMRV) is a xenotropic endogenous virus of the squirrel monkey. The long terminal repeat of the SMRV contains four direct repeats (43 or 42 bp) with different degrees of perfection in the U3 region. Herein, we found two human nuclear proteins (SMBP1 and SMBP2) which bind specifically to the direct repeats with different affinities. The binding proteins recognize overlapped sequences in the 5' region of the repeats. SMBP1 and 2 are monomeric proteins of 35 and 17 kDa, respectively.

Characterization and gene cloning of 1,3-beta-D-glucan synthase from Saccharomyces cerevisiae

1,3-beta-D-Glucan synthase of Saccharomyces cerevisiae was solubilized and purified up to 700-fold by product entrapment. The specific activity of the partially purified enzyme was around 4 mumol glucose incorporated.min-1.mg protein-1. In SDS/PAGE, enrichment of a 200-kDa protein was clearly observed in parallel with the increase in specific activity. mAbs that could immunoprecipitate the 1,3-beta-D-glucan synthase activity were isolated, and some of them also recognized this 200-kDa protein in the Western blot. Internal amino acid sequences of this 200-kDa protein were determined after lysyl endopeptidase digestion. With the information of these amino acid sequences, we cloned two genes, GSC1 and GSC2 (glucan synthase of S. cerevisiae 1 and 2), which are very similar to each other (88% at the amino acid level); hydropathy profiles of both proteins suggest that these genes encode integral membrane proteins which can be assumed to have approximately 16 transmembrane domains. Disruption of each gene was not lethal, but disruption of both genes was lethal. The 1,3-beta-D-glucan synthase activities of membrane and partially purified enzyme of gsc1::URA3 cells were significantly lower than those of the wild-type and gsc2::LEU2 cells.

Prognostic significance of the MIB-1 proliferation index for patients with squamous cell carcinoma of the esophagus

BACKGROUND

A number of studies have indicated that the ki-67 proliferation index is of important prognostic significance for a variety of neoplasias. It was the aim of this study to investigate whether any correlation exits between the MIB-1 proliferation index and various clinicopathologic parameters in squamous cell carcinomas of the esophagus from 72 patients (20 women: median age, 64 years; range, 45-79 years; and 52 men: median age, 61 years; range, 43-77 years).

METHODS

Proliferative activity was determined using an immunohistochemical method with monoclonal antibody MIB-1 (ABC method), for tumor samples obtained from individuals who underwent esophagectomy in the period from 1983 to 1991. The percentage proliferation index (PI) was calculated as the number of positive cells divided by the total number of cells examined. Thirty-nine patients (54%) died of recurrence of esophageal cancer, with a median survival span of 15 months (range, 1-58 months). Thirty-three patients (46%) were still alive at the time of this study; their median follow up was 57 months (range, 40-98 months).

RESULTS

Significant differences between proliferative index values were recorded for the following parameters: survival rate, P < 0.0001; presence of lymph node metastasis, P < 0.05; size of the primary esophageal lesion, P < 0.01; proliferation pattern of the tumor, P < 0.01; and age of the patients, P < 0.05. No correlation was found regarding histologic differentiation, clinical stage, location of the lesion, intraepithelial cancerous spread, lymphatic and blood vessel invasion, and sex of the patients.

CONCLUSION

The MIB-1 proliferation index may be a powerful prognostic marker for patients with squamous cell carcinomas of the esophagus.

[Drug sensitivity and expression of beta-lactamase in enterococci isolated at Okayama University Hospital]

The following results were obtained from a study of Enterococci isolated at the Okayama University Hospital from 1990 to 1994. 1) The isolation frequency of Enterococci was about 6% for each year. 2) The percentage of Enterococcus faecalis (E. faecalis) among Enterococci decreased each year, but the percentage of Enterococcus faecium (E. faecium), and Enterococcus avium (E. avium) increased each year. 3) Results of drug sensitivity tests revealed that the incidence of ofloxacin (OFLX) resistant E. faecalis and E. avium increased each year. Also, the resistance of E. faecalis to ampicillin (ABPC), the primary medication choice for treating E. faecalis, increased each year. 4) A few vancomycin (VCM) non-sensitive Enterococci were isolated. These bacteria showed low-sensitivity toward ABPC, imipenem (IPM), gentamicin (GM), and OFLX, and the extent of multiple drug resistance increased each year. 5) One hundred strains of Enterococci were selected to examine the expression of beta-lactamase using the broth method and the iodine-starch method. However, beta-lactamase producing strains were not detected.

Brain histaminergic system in mast cell-deficient (Ws/Ws) rats: histamine content, histidine decarboxylase activity, and effects of (S) alpha-fluoromethylhistidine

The mast cell-deficient [Ws/Ws (White spotting in the skin)] rat was investigated with regard to the origin of histamine in the brain. No mast cells were detected in the pia mater and the perivascular region of the thalamus of Ws/Ws rats by Alcian Blue staining. The histamine contents and histidine decarboxylase (HDC) activities of various brain regions of Ws/Ws rats were similar to those of +/+ rats except the histamine contents of the cerebral cortex and cerebellum. As the cerebral cortex and cerebellum have meninges that are difficult to remove completely, the histamine contents of these two regions may be different between Ws/Ws and +/+ rats. We assume that the histamine content of whole brain with meninges in Ws/Ws rats is < 60% of that in +/+ rats. So we conclude that approximately half of the histamine content of rat brain is derived from mast cells. Next, the effects of (S) alpha-fluoromethylhistidine (FMH), a specific inhibitor of HDC, on the histamine contents and HDC activities of various regions of the brain were examined in Ws/Ws rats. In the whole brain of Ws/Ws rats, 51 and 37% of the histamine content of the control group remained 2 and 6 h, respectively, after FMH administration (100 mg/kg of body weight). Therefore, we suggest that there might be other histamine pools including histaminergic neurons in rat brain.

Antigen-receptor induced clonal expansion and deletion of lymphocytes are impaired in mice lacking HS1 protein, a substrate of the antigen-receptor-coupled tyrosine kinases

HS1, an intracellular protein expressed specifically in hematopoietic cells, is rapidly tyrosine phosphorylated after cross-linking of antigen receptors on B and T lymphocytes, implicating involvement of this molecule in the signal transduction pathways from the antigen receptors as a substrate of membrane-associated tyrosine kinase(s). The development of lymphoid cells in HS1-deficient mice, generated through gene targeting, appeared normal. However, antibody production to T-independent antigen and proliferative responses of splenic B and T cells after cross-linking of the antigen receptors were impaired in these mutant mice. Furthermore, B cells in the peritoneal cavity of the mutant mice were resistant to multivalent cross-linking of the antigen receptor, which causes apoptosis of such cells in normal mice. Crossing the HS1-deficient mice with the mice harboring transgenes encoding alpha and beta chains of T-cell antigen receptor against a male H-Y antigen resulted in a progeny that demonstrated a significantly impaired ability of thymic negative selection. These results indicate that HS1 is a novel molecule involved in the antigen-receptor-derived signaling pathways and plays important roles not only in clonal expansion, but also in clonal deletion of B and T cells.

Cysteine proteinases in GH4C1 cells, a rat pituitary tumor cell line, are secreted by the constitutive and regulated secretory pathways

Secretory granules of GH4C1 cells, a rat pituitary tumor cell line, are known to be induced by the treatment of estradiol (E2), insulin, and epidermal growth factor (EGF). We examined changes in the localization of cathepsins B, H, and L, lysosomal cysteine proteinases, in GH4C1 cells before and after hormonal treatment. Northern blotting and immunofluorescence microscopy showed that both mRNAs and intracellular protein concentrations of these enzymes were increased in the hormone-induced cells. By immunoelectron microscopy, immunogold particles indicating cathepsins B, H, and L were localized not only in lysosomes but also in some secretory granules. To further examine the molecular forms of these proteinases in secretory granules, radiolabeling and immunoprecipitation methods were applied to the media of the cells incubated with or without secretagogues (100 nM 12-O-tetradecanoylphorbol-13-acetate and 50 microM forskolin); the proforms of cathepsins B, H, and L were secreted from the cells by the constitutive pathway, whereas the mature forms of cathepsins B and H, and the proform and mature form of cathepsin L were secreted by the regulated pathway. These results suggest that in hormone-induced GH4C1 cells, cathepsins B, H, and L are sorted from the Golgi complex not only into lysosomes but also into secretory granules, in which proforms of cathepsins B and H, and a part of procathepsin L are processed into mature forms.

[Study on pyrimidine nucleoside phosphorylase (PyNPase) activity in resected tissues of patients with gastric cancer]

Pyrimidine nucleoside phosphorylase (PyNPase) activity was measured in gastric cancer tissue from 25 patients who underwent resections of gastric cancer. The relation between the activity and host and tumor factors in gastric cancer was studied, and the following results were obtained. 1. PyNPase activity was 128.3 +/- 99.5 in cancer tissue and 37.2 +/- 23.1 in non-cancer tissue. The level was significantly higher in cancer tissue (p < 0.0001). 2. With respect to host factors, the PyNPase activity tended to be high in patients in whom cell-mediated immune response was maintained. 3. With respect to tumor factors, the values tended to be high in patients who were positive for lymph vessel and venous invasion, and positive for lymph node metastasis. 5'-deoxy-5-fluorouridine(5'-DFUR) is an anticancer agent which manifests antitumor effects when it is transformed into 5-FU by PyNPase. When this agent is administered to gastric cancer patients, it can be expected to be more effective in the above types of patients because of its characteristics.

Restoration of surface IgM-mediated apoptosis in an anti-IgM-resistant variant of WEHI-231 lymphoma cells by HS1, a protein-tyrosine kinase substrate

The HS1 protein is one of the major substrates of non-receptor-type protein-tyrosine kinases and is phosphorylated immediately after crosslinking of the surface IgM on B cells. The mouse B-lymphoma cell line WEHI-231 is known to undergo apoptosis upon crosslinking of surface IgM by anti-IgM antibodies. Variants of WEHI-231 that were resistant to anti-IgM-induced apoptosis expressed dramatically reduced levels of HS1 protein. Expression of the human HS1 protein from an expression vector introduced into one of the variant cell lines restored the sensitivity of the cells to apoptosis induced by surface IgM crosslinking. These results suggest that HS1 protein plays a crucial role in the B-cell antigen receptor-mediated signal transduction pathway that leads to apoptosis.

Simultaneous occurrence of aneurysmal subarachnoid hemorrhage and remote intracerebral hemorrhage--case report

A 77-year-old female presented with a rare aneurysmal subarachnoid hemorrhage accompanied by a remote hypertensive intracerebral hemorrhage. With a past history of hypertension, she suddenly developed right hemiparesis followed by delayed loss of consciousness. Left carotid angiography demonstrated a left internal carotid-posterior communicating artery aneurysm. The intracerebral hematoma was located in the posterior limb of the internal capsule ipsilateral to the ruptured aneurysm. The aneurysm was clipped with a fenestrated clip 3 weeks after the onset. The rise in blood pressure at the onset of intracerebral hemorrhage probably caused the rupture of the internal carotid-posterior communicating artery aneurysm.

Simultaneous determinations of histamine and N tau-methylhistamine by high-performance liquid chromatography-chemiluminescence coupled with immobilized diamine oxidase

A method for the simultaneous determinations of histamine and its metabolite N tau-methylhistamine by HPLC-chemiluminescence coupled with immobilized diamine oxidase was developed. The method was based on the determination of chemiluminescence formed by the reaction of a luminol-ferricyanide mixture in alkaline medium with hydrogen peroxide which is one of the metabolic products of histamine and N tau-methylhistamine formed by diamine oxidase. HPLC with postcolumn derivatization resulted in good separation of the two amines and gave linear relationships between the concentrations of both and their chemiluminescence intensities. The lower limits of chemiluminescent detection of histamine and N tau-methylhistamine were 5 and 10 pmol, respectively. The immobilized column showed good operational stability for more than 1 month, during which period 200 samples were analyzed. With this system, the histamine contents of the cerebral cortex, forestomach, glandular stomach, and kidney of Wistar rats were found to be 0.30, 58, 396, and 2.4 nmol/g wet wt, respectively. These values are very similar to those determined by HPLC-fluorometry. The N tau-methylhistamine contents of these tissues were 0.36, 0.40, 0.72, and 3.8 nmol/g wet wt, respectively. This method will be useful for studying the roles of histamine in both brain and peripheral tissues.

Cloning and sequence analysis of the aminopeptidase My gene from Mycoplasma salivarium

The complete nucleotide sequence of a major component of aminopeptidase My purified from Mycoplasma salivarium was determined. The protein gene encoded a protein consisting of 520 amino acids with a molecular mass of 58079 Da. The protein contained two tryptophan residues, one of which was encoded by UGA. A computer-aided homology search suggested that aminopeptidase My had properties similar to those of leucine aminopeptidase (EC 3.4.11.1).

A novel cell surface antigen, immature thymocyte antigen-1, is involved in the differentiation of murine thymocytes

A mAb, 1-23, which recognizes a novel cell surface Ag on immature murine thymocytes (designated as IMT-1 for immature thymocyte antigen-1) was prepared. IMT-1 was found to be expressed on 40 to 50% of CD4-8- double negative (DN), 5 to 10% of CD4-8+, and 5 to 20% of CD4+8+ double positive (DP) thymocytes in adult mice, but not expressed on CD4+8- thymocytes or peripheral T lymphocytes. It was not expressed on either nonlymphoid cell lines or thymic stromal cells. In subsets of DN thymocytes, IMT-1 was detected on 40 to 50% of the heat-stable Ag+, 15% of CD44+25+, 70% of CD44-25+, and 70% of CD44-25- populations, whereas it was not detected on heat-stable Ag- and CD44+25- populations. IMT-1+ thymocytes expressed low levels of or no CD3 molecules. In fetal thymuses, IMT-1 was expressed on a minor population of thymocytes at day 14.5 and 15.5 of gestation. However, at day 16.5 of gestation, a majority of DN as well as DP thymocytes became IMT-1-positive. Addition of the 1-23 Ab to the fetal thymus organ culture relatively increased CD8+ SP thymocytes. These results show that IMT-1 is expressed during the late DN stage as well as the early DP stage of thymocyte maturation and suggest the possible involvement of IMT-1 in thymocyte differentiation.

A novel cell surface antigen, immature thymocyte antigen-1, is involved in the differentiation of murine thymocytes

A mAb, 1-23, which recognizes a novel cell surface Ag on immature murine thymocytes (designated as IMT-1 for immature thymocyte antigen-1) was prepared. IMT-1 was found to be expressed on 40 to 50% of CD4-8- double negative (DN), 5 to 10% of CD4-8+, and 5 to 20% of CD4+8+ double positive (DP) thymocytes in adult mice, but not expressed on CD4+8- thymocytes or peripheral T lymphocytes. It was not expressed on either nonlymphoid cell lines or thymic stromal cells. In subsets of DN thymocytes, IMT-1 was detected on 40 to 50% of the heat-stable Ag+, 15% of CD44+25+, 70% of CD44-25+, and 70% of CD44-25- populations, whereas it was not detected on heat-stable Ag- and CD44+25- populations. IMT-1+ thymocytes expressed low levels of or no CD3 molecules. In fetal thymuses, IMT-1 was expressed on a minor population of thymocytes at day 14.5 and 15.5 of gestation. However, at day 16.5 of gestation, a majority of DN as well as DP thymocytes became IMT-1-positive. Addition of the 1-23 Ab to the fetal thymus organ culture relatively increased CD8+ SP thymocytes. These results show that IMT-1 is expressed during the late DN stage as well as the early DP stage of thymocyte maturation and suggest the possible involvement of IMT-1 in thymocyte differentiation.

Isolation and characterization of a peptide isomerase from funnel web spider venom

A novel peptide isomerase was purified from the venom of funnel web spider, Agelenopsis aperta. The complete primary structure of the isomerase has been established by sequence analyses of polypeptide chains, assignments of disulfide bridges, carbohydrate analyses, and mass spectrometry of sugar chains. The isomerase was found to be a 29-kDa polypeptide that consists of an 18-residue light chain and a 243-residue heavy chain connected by a single disulfide bridge. The heavy chain contains three intramolecular disulfide bridges and one N-linked oligosaccharide chain with a simple trimannosyl core structure. A sequence homology search showed a significant similarity of the enzyme with serine proteases, particularly around a putative catalytic triad of the isomerase. The isomerase specifically interconverts the configuration of Ser46 of a 48-amino-acid peptide, omega-agatoxin-TK, and the conversion rate from L-Ser to D-Ser was approximately two times faster than the reverse reaction.

Ontogenetic development of histamine receptor subtypes in rat brain demonstrated by quantitative autoradiography

The postnatal ontogenetic development of the histamine receptor subtypes was studied in rat brain by quantitative receptor autoradiography with highly sensitive imaging plates. H1 receptor binding sites labeled with [3H]pyrilamine were detected on postnatal day 2 (P2) and increased very slowly until P9, and then rapidly reaching the adult levels in the hypothalamus, hippocampus, and amygdala by P16. The densities of H1 receptor binding sites in the cortex, striatum, thalamus, and substantia nigra were relatively low during development. H3 receptor binding sites labeled with [3H](R) alpha-methylhistamine were not detectable until P9. On P9, their density was higher in the substantia nigra than in other regions. Subsequently, H3 receptor binding increased, reaching the adult levels in the substantia nigra on P16 and in the other regions on P23. The histamine concentration was initially very high, but decreased to the adult level by P16. On the contrary, the activity of L-histidine decarboxylase of whole brain tissue was low on P5, and increased markedly from P16 to P23, to the adult level on P30. Administration of (S) alpha-fluoromethylhistidine (FMH), a specific inhibitor of L-histidine decarboxylase (HDC), significantly decreased both the HDC activity and histamine concentration during postnatal development. FMH treatment did not change H1 receptor binding in any brain region, but significantly increased H3 receptors in the substantia nigra and striatum on P23. Unilateral injection of 6-hydroxydopamine into the striatum on P2 resulted in up-regulation of H3 receptor binding sites in the dorsomedial (11%) and dorsolateral (18%) regions of the striatum and substantia nigra (31%) on P23, but no change in the H3 receptor density in the nucleus accumbens or frontal cortex on P11 and P23. These results demonstrate that the developmental patterns of H1 and H3 receptors are heterogeneous and independent of each other. There are marked mismatches of presynaptic and postsynaptic markers of the histaminergic neuron system as in other aminergic systems.

Effects of fluvastatin on human biliary lipids

The 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors have rapidly become widespread in the treatment of hypercholesterolemia and are known to be variable in efficacy. To investigate the effect on biliary lipids, a 3-month study using fluvastatin was devised. A total of 19 patients were enrolled in this study: all had hypercholesterolemia (7 men, 12 women; 13 with type IIa, 6 with type IIb). After an observation period of 4-6 weeks with placebo, fluvastatin at a daily dose of 30 mg was administered for 3 months. Fasting blood samples were taken early in the morning, before, and once a month during 3 months of fluvastatin treatment, for measurement of serum lipids. Cerulein-stimulated bile in the gallbladder was sampled using a duodenal tube, and the changes in biliary lipids were assessed. There was a marked decrease in serum total cholesterol after 12 weeks of treatment (21%; p < 0.001). However, there was no significant difference in the bile cholesterol saturation index (CSI): values before and after 3 months of drug administration were 0.93 and 0.99, respectively (Admirand-Small method). There were no significant changes in either the fatty acid composition of biliary lecithin or in the bile acid composition of bile. In conclusion, on the basis of these results, short-term (3 months) administration of fluvastatin does not appear to affect CSI.

Laser vaporization of the ovarian surface in polycystic ovary disease results in reduced ovarian hyperstimulation and improved pregnancy rates

OBJECTIVE

Our purpose was to examine the efficacy of laser vaporization of the ovarian surface in polycystic ovary disease to reduce repeated ovarian hyperstimulation syndrome and thereby improve pregnancy outcome.

STUDY DESIGN

Twenty-six infertile patients with polycystic ovary disease who previously had ovarian hyperstimulation syndrome after stimulation with human menopausal gonadotropin and who failed to conceive were studied. All patients were treated by potassium titanyl phosphate and neodymium-yttrium-aluminum-garnet laser and evaluated. Patients not ovulating spontaneously after vaporization were treated with either clomiphene citrate or human menopausal gonadotropin.

RESULTS

After vaporization spontaneous ovulation was confirmed in six patients. For ovulation induction three patients received clomiphene citrate and 17 received human menopausal gonadotropin. Of the patients treated with human menopausal gonadotropin, mild ovarian hyperstimulation syndrome was found in three patients, and the incidence of ovarian hyperstimulation syndrome decreased significantly. Pregnancy was confirmed in 19 of 26 patients.

CONCLUSION

Laser vaporization is promising for the prevention of ovarian hyperstimulation syndrome and improving pregnancy outcome in patients with polycystic ovary disease who have previously had ovarian hyperstimulation syndrome.

Upper-extremity Musculoskeletal Disorders in Keyboard Operators in Brazil: A Cross-sectional Study

This study sought to determine the prevalence of upper-extremity musculoskeletal disorders (UEMSDs) among keyboard operators in Sao Paulo, Brazil, and to compare this prevalence with that among other office workers. One hundred and thirty keyboard operators (mean age 33 years, 60 male/70 female) and 138 office workers (mean age 35 years, 82 male/56 female) from two computing centers were interviewed by a research assistant using a standardized questionnaire. Symptomatic subjects, defined as those who reported upper extremity pain or lost work time due to pain in the preceding 12 months, were examined by a rheumatologist. Mean (SD) lengths of employment were 9 (6) years for keyboard operators and 8 (6) years for office workers. Upper-extremity pain during the preceding seven days was reported by 66 keyboard operators (51%) and by 18 office workers (13%) (p < 0.0001); during the preceding 12 months, by 90 keyboard operators (69%) and by 26 office workers (19%) (p < 0.0001). UEMSDs were diagnosed following physical examination in 50 keyboard operators and in 12 office workers (9%) (p < 0.0001). Tenosynovitis was the most common disorder diagnosed among the keyboard operators (n = 23). Among the keyboard operators the prevalence of UEMSDs was significantly lower for males (p = 0.017, OR = 0.38, 95%CI = 0.17-0.86). The presence of a diagnosed UEMSD was significantly associated with duration of employment (p = 0.005) and lack of or insufficient rest breaks (p = 0.012). Keyboard operators had significantly more UEMSDs than did office workers. Strategies aimed at the reduction of repetitive strain injuries among keyboard operators, such as the provision of adequate work breaks, should be evaluated.

Characterization of a chemically reactive propranolol metabolite that binds to microsomal proteins of rat liver

We have characterized a chemically reactive propranolol (PL) metabolite which binds to proteins in rat liver microsomes. During incubation with rat liver microsomes (1 mg of protein) fortified with an NADPH-generating system, 4-hydroxypropranolol (4-OH-PL) quickly disappeared from the reaction medium, but none of the possible metabolite peaks was detected under the high-performance liquid chromatographic conditions used. The consumption of 4-OH-PL depended on microsomes and NADPH. The reaction was not affected by inhibitors of cytochrome P450 or FAD monooxygenase, but was markedly diminished in the presence of cytosol and ascorbic acid. The effect of cytosol was inhibited by potassium cyanide but not by sodium benzoate or dimethyl sulfoxide, and was also not affected by heating at 60 degrees C for 30 min, suggesting that superoxide (SO) ion was involved in the reaction and that it was blocked by superoxide dismutase (SOD) present in the cytosol. Cu,Zn-SOD, purified from cytosol, effectively mimicked the suppressive effect of cytosol. Incubation of 4-OH-PL in an SO-generating system of xanthine and xanthine oxidase generated 1,4-naphthoquinone (1,4-NQ), which was identified by TLC, HPLC, and GC/MS. 1,4-NQ was also formed in microsomal incubates containing NADPH and small amounts of microsomes (below 0.1 mg of protein). These results indicate that 4-OH-PL is converted by SO, or some reactive oxygen species derived from it, to 1,4-NQ which binds to proteins and is one of the reactive metabolites of PL.