Perceived physical and emotional trauma as precipitating events in fibromyalgia. Associations with health care seeking and disability status but not pain severity

The spectrophotometry and photofluorescence techniques were used in the studies on photochemical transformations of lactate dehydrogenase exposed to UV irradiation with a dose of 2.25 kJ/m2, in the native state and in the presence of exogenous modifiers: sodium azide, beta-carotene, histidine, D-mannitol, and tret-butanol. It was shown that UV irradiation of the mixtures of lactate dehydrogenase with sodium azide, beta-carotene, and histidine results in restoration (by 99, 65, and 63%, respectively) of the level of catalytic activity of the enzyme as compared to that observed after irradiating it in the absence of the protectors. The protective effect provided by mannitol during UV irradiation of the lactate dehydrogenase was 23%. Thus, it was shown that active oxygen species--singlet molecular oxygen and hydroxyl radical--make significant contributions to photomodification of lactate dehydrogenase.     

A role for the actin cytoskeleton of Saccharomyces cerevisiae in bipolar bud-site selection

The effects of structure on the estrogenicity and antiestrogenicity of hydroxylated polychlorinated biphenyls were investigated using the following estrogen-sensitive assays: competitive binding to the rat and mouse cytosolic estrogen receptor (ER); immature rat and mouse uterine wet weight, peroxidase and progesterone receptor (PR) levels; induction of luciferase activity in HeLa cells stably transfected with a Gal4:human ER chimera and a 17mer-regulated luciferase reporter gene; proliferation of MCF-7 human breast cancer cells; induction of chloramphenicol acetyl transferase (CAT) activity in MCF-7 cells transiently transfected with a full-length human ER expression plasmid and a plasmid containing an estrogen-responsive vitellogenin A2 promoter linked to a CAT reporter gene. The chemicals synthesized for this study contained a 4-hydroxy group in one ring, a 2- or 3-chloro substituent meta or ortho to the hydroxyl group, and variable substitution (2',3',4',5'-, 2',3',4',6'-, 2',3',5',6'-tetrachloro and 2',4',6'-trichloro) in the chlorophenyl ring. The compounds included: 2,2',3',4',5'- (A), 2,2',3',4',6'- (B), and 2,2',3',5',6'-pentachloro- (C); 2,2',4',6'-tetrachloro-4-biphenylol (D); 2',3,3',4',5'- (E), 2',3,3',4',6'- (F), and 2',3,3',5',6'-pentachloro (G); and 2',3,4',6'-tetrachloro-4-biphenylol (H). With the exception of 2',3,4',6'-tetrachloro-4-biphenylol (H), all of the compounds competitively bound to the mouse and rat ER with relative binding affinities [compared to 17beta-estradiol (E2)] varying from 1.4 x 10(-3) to 5.3 x 10(-5). The structure-ER binding relationships for the hydroxy-PCB congeners were different in the rat and mouse, and no dose-dependent estrogenic activities were observed in the mouse or rat uterus. Several hydroxy-PCB congeners exhibited antiestrogenic activity (primarily in the mouse uterus) and two compounds, 2,2',3',5',6- and 2,2',3',4',6'-pentachloro-4-biphenylol, inhibited E2-induced uterine wet weight, PR binding, and peroxidase activity in the mouse uterus. 2,2',3',4',5'- and 2,2',3',4',6'-Pentachloro-4-biphenylol induced CAT activity in MCF-7 cells transiently transfected with the Vit-CAT plasmid; the remaining congeners did not induce CAT activity but exhibited antiestrogenic activity in MCF-7 cells cotreated with 10(-9) E2 plus 10(-5) M hydroxy-PCBs. Complementary structure-estrogenicity relationships were observed utilizing the HeLa cell luciferase induction and MCF-7 cell proliferation assays. The placement of the 2- or 3-chloro groups in the phenolic ring had minimal effects on estrogenic activity, whereas 2,4,6-trichloro- and 2,3,4,6-tetrachloro substitution in the chlorophenyl ring (B, D, F, and H) were required for this response. Substitution in the phenolic ring was also not important for structure-antiestrogenicity relationships, and the most active compounds (A, C, E, and G) contained 2',3',4',5'- and 2',3',5',6'-tetrachlorophenyl groups. Thus, structure-estrogenicity/antiestrogenicity relationships for this series of hydroxy-PCBs were complex and response-specific.     

Vascular MADs: two novel MAD-related genes selectively inducible by flow in human vascular endothelium

Vascular endothelium is an important transducer and integrator of both humoral and biomechanical stimuli within the cardiovascular system. Utilizing a differential display approach, we have identified two genes, Smad6 and Smad7, encoding members of the MAD-related family of molecules, selectively induced in cultured human vascular endothelial cells by steady laminar shear stress, a physiologic fluid mechanical stimulus. MAD-related proteins are a recently identified family of intracellular proteins that are thought to be essential components in the signaling pathways of the serine/threonine kinase receptors of the transforming growth factor beta superfamily. Smad6 and Smad7 possess unique structural features (compared with previously described MADs), and they can physically interact with each other, and, in the case of Smad6, with other known human MAD species, in endothelial cells. Transient expression of Smad6 or Smad7 in vascular endothelial cells inhibits the activation of a transfected reporter gene in response to both TGF-beta and fluid mechanical stimulation. Both Smad6 and Smad7 exhibit a selective pattern of expression in human vascular endothelium in vivo as detected by immunohistochemistry and in situ hybridization. Thus, Smad6 and Smad7 constitute a novel class of MAD-related proteins, termed vascular MADs, that are induced by fluid mechanical forces and can modulate gene expression in response to both humoral and biomechanical stimulation in vascular endothelium.     

Correction of hypermutability, N-methyl-N'-nitro-N-nitrosoguanidine resistance, and defective DNA mismatch repair by introducing chromosome 2 into human tumor cells with mutations in MSH2 and MSH6

The human DNA mismatch repair genes hMSH2 and hMSH6 encode the proteins that, together, bind to mismatches to initiate repair of replication errors. Human tumor cells containing mutations in these genes have strongly elevated mutation rates in selectable genes and at microsatellite loci, although mutations in these genes cause somewhat different mutator phenotypes. These cells are also resistant to killing by certain drugs and are defective in mismatch repair. Because the elevated mutation rates in these cells may lead to mutations in additional genes that are causally related to the other defects, here we attempt to establish a cause-effect relationship between the hMSH2 and hMSH6 gene mutations and the observed phenotypes. The endometrial tumor cell line HEC59 contains mutations in both alleles of hMSH2. The colon tumor cell line HCT15 contains mutations in hMSH6 and also has a sequence change in a conserved region of the coding sequence for DNA polymerase delta, a replicative DNA polymerase. We introduced human chromosome 2 containing the wild-type hMSH2 and hMSH6 genes into HEC59 and HCT15 cells. Introduction of chromosome 2 to HEC59 cells restored microsatellite stability, sensitivity to N-methyl-N'-nitro-N-nitrosoguanidine treatment, and mismatch repair activity. Transfer of chromosome 2 to HCT15 cells also reduced the mutation rate at the HPRT locus and restored sensitivity to N-methyl-N'-nitro-N-nitrosoguanidine treatment and mismatch repair activity. The results demonstrate that the observed defects are causally related to mutations in genes on chromosome 2, probably hMSH2 or hMSH6, but are not related to sequence changes in other genes, including the gene encoding DNA polymerase delta.     

Metabolic activation of aromatic amines by human pancreas

Epidemiologic studies have suggested that aromatic amines (and nitroaromatic hydrocarbons) may be carcinogenic for human pancreas. Pancreatic tissues from 29 organ donors (13 smokers, 16 non-smokers) were examined for their ability to metabolize aromatic amines and other carcinogens. Microsomes showed no activity for cytochrome P450 (P450) 1A2-dependent N-oxidation of 4-aminobiphenyl (ABP) or for the following activities (and associated P450s): aminopyrine N-demethylation and ethylmorphine N-demethylation (P450 3A4); ethoxyresorufin O-deethylation (P450 1A1) and pentoxyresorufin O-dealkylation (P450 2B6); p-nitrophenol hydroxylation and N-nitrosodimethyl-amine N-demethylation (P450 2E1); lauric acid omega-hydroxylation (P450 4A1); and 4-(methylnitrosamino)-1-(3-pyridyl-1-butanol) (NNAL) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) alpha-oxidation (P450 1A2, 2A6, 2D6). Antibodies were used to examine microsomal levels of P450 1A2, 2A6, 2C8/9/18/19, 2E1, 2D6, and 3A3/4/5/7 and epoxide hydrolase. Immunoblots detected only epoxide hydrolase at low levels; P450 levels were <1% of liver. Microsomal benzidine/prostaglandin hydroperoxidation activity was low. In pancreatic cytosols and microsomes, 4-nitrobiphenyl reductase activities were present at levels comparable to human liver. The O-acetyltransferase activity (AcCoA-dependent DNA-binding of [3H]N-hydroxy-ABP) of pancreatic cytosols was high, about twothirds the levels measured in human colon. Cytosols showed high activity for N-acetylation of p-aminobenzoic acid, but not of sulfamethazine, indicating that acetyltransferase-1 (NAT1) is predominantly expressed in this tissue. Cytosolic sulfotransferase was detected at low levels. Using 32P-post-labeling enhanced by butanol extraction, putative arylamine-DNA adducts were detected in most samples. Moreover, in eight of 29 DNA samples, a major adduct was observed that was chromatographically identical to the predominant ABP-DNA adduct, N-(deoxyguanosin-8-yl)-ABP. These results are consistent with a hypothesis that aromatic amines and nitroaromatic hydrocarbons may be involved in the etiology of human pancreatic cancer.     

Human vestibular schwannoma growth in the nude mouse: evaluation of a modified subcutaneous implantation model

HYPOTHESIS: Based on the hypothesis that vestibular schwannomas can be successfully implanted and grown in the nude mouse model, an in vivo experiment was designed for subcutaneous implantation of solid vestibular schwannoma tissue. BACKGROUND: Vestibular schwannomas are benign tumors arising from Schwann cells of cranial nerve VIII. Little in vivo research has been carried out with these tumors, due in part to the difficulty to grow cells in culture or maintain tumor in an animal model. Recently, vestibular schwannomas have been implanted in nude mice with moderate success. The current study evaluates a modification of prior techniques in an effort to establish a dependable research model. METHODS: Thirty-six nude mice were implanted with variable-sized vestibular schwannoma tissue from three human subjects. Volumes implanted ranged from 14-170 mm3. Mice were observed for 28 days and individual volumes recalculated. Eleven of the mice were observed for a total of 56 days with volumes re-evaluated, and tumors subsequently were removed for assessment of viability and vascularity. RESULTS: At 28 days, 36 tumors (100%) showed take with 34 tumors (94%) showing macroscopic growth. The 11 tumors observed for 56 days showed a trend of stable or decreased size at 56 days compared with that of the 28-day measurement. Overall growth from time of implantation to measurements at 56 days was noted in 8 (73%) of 11 tumors when measured at the skin and in 10 (91%) of 11 tumors when direct tumor volume was measured. One hundred percent of tumors evaluated microscopically at 56 days was viable. All tumors at the time of removal had significant vascularity with a mean of 70.68% (SD = 23.42) of surface covered with vessels. There were no significant differences in take and growth for the larger tumor specimens compared with those of smaller sizes. CONCLUSION: Human vestibular schwannomas successfully can be implanted and maintained in the subcutaneous pocket of the nude mouse. This in vivo tumor model provides a reliable, accessible base for further research with vestibular schwannomas.     

Laparoscopic cholecystectomy during pregnancy is safe for both mother and fetus

The use of laparoscopic cholecystectomy in pregnant women has been slow to gain wide acceptance for two reasons: one is the potential for mechanical problems related to the pregnant uterus and the other is fear of fetal injury resulting from instrumentation or the pneumoperitoneum. To assess the effects of laparoscopic cholecystectomy on both the mother and the unborn fetus, we reviewed our surgical experience over a 5-year period analyzing indications for the procedure along with complications and outcome. During this 5-year period, 22 patients ranging in age from 17 to 31 years underwent laparoscopic cholecystectomy during pregnancy. Gestational ages ranged from 5 to 31 weeks with two patients being in the first trimester, 16 in the second, and four in the third. The primary indications for surgical intervention were persistent nausea, vomiting, pain, and inability to eat in 17 patients, acute cholecystitis in three, and choledocholithiasis in two. In all patients a pneumoperitoneum was established by means of a closed technique starting in the right upper quadrant of the abdomen. Two of the 22 patients also underwent successful transcystic common bile duct exploration with removal of common duct stones. All 22 patients survived the surgical procedure without complications, and there were no fetal deaths or premature births related to the procedure. Based on the preceding results, it would appear that laparoscopic cholecystectomy during pregnancy is safe for both the mother and the unborn fetus. Indications for this procedure should include stringent criteria such as unrelenting biliary tract symptoms or the complications of cholelithiasis. If at all possible, when laparoscopic cholecystectomy is indicated, it should be performed either in the second trimester or early in the third.