EGFR mutations in exons 18-21 in sporadic breast cancer.
Explore the source record for details and available documents.
Breast Neoplasms↗
Biomedical subjects
P Chambers
Publications and source records attributed to P Chambers.
Expression of hTERT immortalises normal human urothelial cells without inactivation of the p16/Rb pathway.
The CDKN2A locus is frequently inactivated in urothelial cell carcinoma (UCC), yet how this alteration contributes to bladder tumorigenesis is not known. Although most UCC express telomerase, inactivation of the p16/Rb pathway is generally required for in vitro immortalisation. This and the involvement of p16 in senescence of normal human urothelial cells (NHUC) suggest that CDKN2A deletion may aid bypass of senescence and allow immortalisation. CDKN2A encodes p16 and p14ARF and therefore inactivation of this locus can disrupt both the Rb and p53 tumour suppressor pathways. Retrovirus-mediated transduction was used to specifically modulate the p16/Rb and/or p53 tumour suppressor pathways in NHUC and to express human telomerase reverse transcriptase (hTERT). Expression of hTERT bypassed Rb and p53 pathway-dependent barriers to proliferation and immortalised NHUC. TERT-NHUC had normal karyotypes, were non-tumorigenic and unexpectedly retained CDKN2A. Thus, the phenotypic significance of inactivation of CDKN2A in UCC may not be solely related to bypass of senescence. Phenotypic assays in human urothelial cells have relied on cell strains derived from invasive tumours or NHUC immortalised by expression of SV40-large T. The production of genetically normal but immortal NHUC lines now provides a valuable platform for experiments to examine the timing and combination of events necessary for UCC tumorigenesis.
Base Sequence↗
Systemic scleroderma: a spatiotemporal clustering.
BACKGROUND AND AIMS: The aetiology of systemic scleroderma remains poorly understood. Twin studies suggest a low genetic input. Of the incriminated environmental agents, silica and vinyl chloride monomer exposure appear the most convincing. Spatiotemporal clustering has been demonstrated only three times previously. We now report a fourth cluster around Edenhope, western Victoria in terms of numerator and denominator estimates, cumulative incidence, distribution in time and space, and possible aetiological factors. METHODS: Prevalence/cumulative incidence numerator and denominator values were obtained and validated. Each case was age-and gender-matched with two controls. A standardized postal questionnaire was used to obtain data on current, past history, family history, and occupational and non-occupational environmental exposure. RESULTS: Six systemic scleroderma cases and one mixed connective tissue disease patient with a predominance of scleroderma features were identified. The 5-year cumulative incidence was 6.1/10,000, tenfold higher than the Sydney estimates for a similar, though non-identical time period. The gender ratio was 1:1. No cases were genetically related. A family history of scleroderma was validated in one instance and a family history of Raynaud's was noted in first degree relatives of two cases and one control. In all instances, Edenhope residence preceded disease onset. No one environmental agent was implicated in all cases. CONCLUSION: A spatiotemporal cluster of systemic scleroderma was confirmed and validated. It occurred with a tenfold increased cumulative incidence to that expected and also extended beyond the initially defined 50 km radius of Edenhope. The cases identified were not related. Although no one specific environmental agent was identified, the spatiotemporal clustering would be compatible with an agent occurring at relatively high frequency, but with low disease conversion rates, such as silica inhalation (assuming sufficiently small particle size) or reaction to an infective agent.
Aged↗
Augmentation mammoplasty and "silicone-osis".
BACKGROUND: Claims have been made that breast augmentation induces a previously unrecognized disease ("silicone-osis"). AIMS: To confirm the existence of "silicone-osis", qualify and quantify its characteristics. METHODS: In this population-based retrospective cohort study, the health status of 458 female Sydney residents who had augmentation mammoplasty for cosmetic reasons ("augmentation mammoplasty-exposed" or "exposed" cohort) between 1979 and 1983 was compared with the health status of 687 female Sydney residents who had non-silicone-associated plastic surgery ("augmentation mammoplasty-nonexposed" or "non-exposed" cohort). Both groups were matched for age (+/- 5 years), year of plastic surgery (+/- 2 years), plastic surgeon, anaesthetist and mode of anaesthesia. Outcome measures comprised dummy symptoms to assess reporting bias, as well as symptoms and symptom clusters from a comprehensive 78-symptom list. RESULTS: Dummy variables were not over-reported by the exposed cohort. The following individual symptoms developed more commonly in the exposed cohort after index plastic surgery: "memory loss/confusion", "altered bowel habit", "chest pain made worse by deep breathing", "shortness of breath after walking up 10 steps", "breast pain", "sweating mainly at night" and "tunnel vision". Of eight identified symptom clusters, three were rejected as biologically unimportant: "joint swelling of the bunion joint", "haemorrhoids" and "breast lumps" (the latter two occurring more commonly in the non-exposed cohort). In contrast, five symptom clusters were thought to have potential biological importance and occurred more commonly in the exposed cohort. The symptom "night sweats" was common to all five clusters, and comprised the sole symptom in one instance. The other four multisymptom clusters were also characterized by "low energy" (lethargy) and "pins and needles", whereas "breast pain", "impaired memory", "muscle pain" and "reflux", occurred in three of the four clusters. CONCLUSION: Cluster analysis suggested the existence of a multisystem disorder occurring more commonly in the exposed cohort and characterized by night sweats, lethargy, breast pain, impaired mentation, reflux, paraesthesiae, hand muscle weakness and myalgia. The argument against this being a new disease entity --"silicone-osis"-- however, was its presence, albeit at lower frequency, in the silicone-unexposed cohort. Thus this study did not confirm the existence of a new disease entity "silicone-osis" uniquely and causally associated with silicone exposure. The possible interpretations of these findings are discussed.
Autoimmune Diseases↗
Protective immune responses elicited in mice by immunization with formulations of poly(lactide-co-glycolide) microparticles.
Parenteral administration of microparticle encapsulated DNA elicits immune responses to the encoded antigens. Experiments were performed to test whether the addition of certain lipophilic agents to such formulations enhanced the activity of a beta-galactosidase (beta-gal) DNA vaccine. Addition of either taurocholic acid (TA) or monomethoxy polyethylene-glycol-distearoylphosphatidylehanolamine (PEG-DSPE) increased the efficiency of DNA encapsulation. Immunization of mice with encapsulated DNA formulations containing either compound significantly increased the number of antibody positive responders over that achieved with non-lipid containing particles. Moreover, responding animals demonstrated trends towards higher antibody titers and increased T cell responses. Tumor protection against the CT26.CL25 tumor cell line was demonstrated with lipid and non-lipid containing formulations. These results are the first demonstration of protection obtained by parenteral administration of PLG encapsulated DNA vaccines.
Animals↗
Women's health after plastic surgery.
BACKGROUND: Allegations that exposure to endogenous silicone, especially related to breast implants, might be causally related to connective tissue disease originated from case studies. More recent comparative studies have implied no such increased risk. The aims of the present study were to compare the prevalence and/or incidence of autoimmune and connective tissue disorders in a population-based cohort of female Sydney residents stratified by augmentation mammoplasty status. METHODS: In this population-based retrospective cohort study, the health status of female Sydney residents who had augmentation mammoplasty for cosmetic reasons between 1979 and 1983 was compared with that of female Sydney residents who had non-silicone-associated plastic surgery over the same period. Both groups were matched for age (+/- 5 years), year of plastic surgery (+/- 2 years), plastic surgeon, anaesthetist and mode of anaesthesia. Outcome measures comprised rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, sicca symptoms polymyositis/ dermatomyositis, connective tissue disease overlap, digital vasospasm, abnormal nailfold capillaroscopy, elevated antinuclear antibody titre, carpal tunnel syndrome, tendonitis, osteoarthritis, psoriatic arthritis, livedo reticularis, thyroid disease, multiple sclerosis, axillary lymphadenopathy, fibromyalgia and breast carcinoma. RESULTS: There was no difference in the occurrence of connective tissue diseases or connective tissue disease-related parameters, thyroid disorders, fibromyalgia or multiple sclerosis between cohorts. However, axillary adenopathy and low titre positive antinuclear antibody (ANA) occurred with a significantly greater frequency in the exposed cohort (odds ratio (OR) = 3.50, 95% confidence interval (CI) = 2.10-5.84 and OR = 1.29, 95% CI = 1.03-1.62, respectively). Axillary adenopathy correlated with capsular contracture (relative risk (RR) = 2.07, 95% CI = 1.22-3.51) and also the self-reported development of digital vasospasm (RR = 3.20, 95% CI = 1.46-7.03) after breast augmentation. CONCLUSIONS: No association was found between augmentation mammoplasty exposure and various connective tissue diseases and/or their related features. However, axillary adenopathy and low titre ANA were detected more frequently in the exposed cohort. Women with axillary adenopathy were more likely to have breast capsular contracture and report digital vasospasm post-dating surgery. Given comparable frequencies of higher titre ANA of both cohorts, the finding of elevations of low titre ANA is of dubious clinical significance.
Adult↗
Two methods for quantifying DNA extracted from poly(lactide-co-glycolide) microspheres.
DNA can be formulated with synthetic polymers such as poly(lactide-co-glycolide) (PLG) to generate microparticles. Researchers have used either UV spectroscopy or fluorometry with PicoGreen((R)) dye to quantify PLG-encapsulated DNA. While the sensitivity of DNA detection and quantification by PicoGreen is higher ( approximately 12 pg/ml) compared to UV ( approximately 0.5 microg/ml), each method as an analytical tool has limitations. The premise of this work addresses the usefulness and limitations of each method to determine encapsulation efficiencies in PLG microspheres post-process, and to quantify release of DNA from microspheres during in vitro release experiments. In addition, assay conditions for accurate and reproducible extraction of DNA from PLG microspheres using a biphasic (aqueous/organic) solvent system are described. It was also determined that residual poly(vinyl alcohol) and DNA isoforms (linear, nicked, supercoiled) affected PicoGreen/DNA fluorescence values.
DNA↗
The production of nerve growth factor by human bladder smooth muscle cells in vivo and in vitro.
OBJECTIVE: To measure the concentrations of nerve growth factor (NGF) in tissue biopsies taken from subjects with a normal bladder and from patients diagnosed to have idiopathic detrusor instability (associated with a reduction in the density of motor nerves), and to use an in vitro model to study the mechanisms of NGF expression. MATERIALS AND METHODS: Biopsy specimens were obtained during endoscopic and open surgery from patients undergoing routine bladder surgery. The patients were divided into two categories based upon urodynamic characterization. The NGF content in samples from 11 normal bladders and seven idiopathic unstable bladders were measured using an enzyme-linked immunosorbent assay. The mechanisms influencing net NGF production were explored using detrusor cells in vitro. RESULTS: The mean (SEM) NGF content was significantly higher in unstable tissues, at 0.96 (0.05) pg/microg protein, than in the normal bladder, at 0.53 (0.05) pg/microg protein. In the cell model, acetylcholine (10 micromol/L), noradrenaline (1 and 10 micromol/L) and ATP (1 micromol/L) caused a significant increase in net NGF production; acetylcholine at 1 micromol/L had no effect. Direct stimulation of protein kinase C (PKC) by phorbol ester (33 ng/mL) or elevation of cAMP using forskolin (10 micromol/L) increased NGF, suggesting that at least two intracellular pathways (PKC- and PKA-dependent) are involved. The expression of c-Fos was increased by phorbol 12-myristate 13-acetate added before NGF, suggesting that c-Fos may be involved in regulating NGF production. CONCLUSION: These data suggest a role for NGF in the physiology and pathophysiology of the human bladder, and indicate some of the possible mechanisms which might regulate NGF production.
Biopsy↗
Male systemic sclerosis and occupational silica exposure-a population-based study.
BACKGROUND: The continuing uncertainty about the silica-systemic sclerosis relationship led to the investigation of its role as a disease determinant in a large population-based study of systemic sclerosis. AIMS: To compare the frequency, socioeconomic and educational status, age-specific prevalence and duration of occupational silica exposure in males with and without systemic sclerosis. To assess the temporal relationship between exposure and disease onset. To estimate disease latency. To compare disease characteristics between silica-exposed and non-silica-exposed male cases. METHODS: The study was case-control in design. The exposure variable was occupational silica exposure as assessed by an occupational health officer blinded to case/control status and the outcome variable was systemic sclerosis. The employed instrument comprised either a standardised telephone questionnaire (interviewed cases and controls) or medical records (deceased or living-status-unknown cases). RESULTS: Sixty of 160 cases (37.5%) and 11 of 83 (13.3%) controls had occupational silica exposure (OR=3.93; 1.84-8.54). Comparison of data between 64 interviewed cases and all controls demonstrated initial occupational silica exposure occurring before age 40, comparable educational status but significantly different cumulative socioeconomic status with cases being over-represented in semi-skilled and unskilled occupations. Cross-sectional 'current' occupational data underestimated cumulative silica exposure by more than 50%. Silica exposure uniformly preceded onset of second disease symptoms and disease diagnosis. In most, it also preceded onset of first disease symptoms. Disease latency approximated two decades. No disease features distinguished silica-associated systemic sclerosis from idiopathic systemic sclerosis. The duration of silica exposure in the interviewed silica-exposed cases did not significantly exceed that of silica-exposed controls. CONCLUSIONS: Male systemic sclerosis displays socioeconomic dependence. Silica is a disease determinant in male systemic sclerosis, with disease features including a long latency and clinical characteristics indistinguishable from idiopathic disease. Cross-sectional 'current' occupational data underestimate cumulative occupational silica exposure.
Adolescent↗
Drug resistance and drug combination features of the human immunodeficiency virus inhibitor, BCH-10652 [(+/-)-2'-deoxy-3'-oxa-4'-thiocytidine, dOTC].
The heterosubstituted nucleoside analogue dOTC [( )-2'-deoxy-3'-oxa-4'-thiocytidine, BCH-10652] is a racemic compound structurally related to 3TC (lamivudine), but has the oxygen and sulphur in the furanosyl ring transposed. Both the enantiomers (-)dOTC (BCH-10618) and (+)dOTC (BCH-10619) had equivalent activity against wild-type strains of HIV-1 in C8166 T-cells (EC50 1.0-10.0 microM) and in PBMCs (EC50 0.1-3.0 microM). Investigation of the activity of dOTC and its enantiomers against laboratory strains of HIV-1 with defined resistance to 3TC, AZT (zidovudine), ddl (didanosine), PMEA (adefovir), nevirapine and saquinavir indicated that sensitivity was maintained (<3-fold change in EC50) in all cases, with the exception of HIV-1RF 3TC-resistant viruses. The degree of resistance recorded for dOTC (four- to sevenfold), (-)dOTC (five- to eightfold) and (+)dOTC (five- to >18-fold) against these M1841 or M184V mutants, was significantly less than that recorded for 3TC (>100-fold). In addition, the inhibitory effect of the compounds against clinical isolates of HIV-1 recovered from patients with suspected resistance to 3TC and AZT was investigated. Clinical isolates were genotyped using the Murex Line Probe Assay (LiPA) and subgrouped into wild-type, 3TC-resistant and dual 3TC/AZT-resistant, as well as undefined or mixed genotype populations. Compared with the mean EC50 values obtained with genotypically and phenotypically wild-type clinical isolates, the mean EC50 values calculated for isolates phenotypically resistant to 3TC or 3TC and AZT were only 2.6-, 1.6- and 8.2-fold higher for dOTC, (-)dOTC and (+)dOTC, respectively. When the rate of emergence of virus resistant to dOTC and its enantiomers in vitro was investigated, virus resistant to (+)dOTC was readily selected for (<10 passages), and a methionine (ATG) to isoleucine (ATA) amino acid change at codon 184 was identified. In contrast, virus resistant to dOTC and (-)dOTC took longer to appear (15-20 passages), with a methionine (ATG) to valine (GTG) amino acid change at position 184 identified in both cases. In addition, virus passaged 20 times in the presence of dOTC also had a partial lysine (AAA) to arginine (AGA) exchange at position 65. These viruses showed only low-level resistance to dOTC and its enantiomers, but were highly resistant to 3TC. The antiviral effects of dOTC in combination with the nucleoside RT inhibitors AZT, 3TC, d4T (stavudine) and ddl, the non-nucleoside RT inhibitor nevirapine and the protease inhibitors saquinavir, ritonavir and indinavir was investigated. Two-way drug combination assays were carried out in peripheral blood mononuclear cell (PBMC) cultures by measuring the reduction in p24 viral antigen levels, and data was analysed using the MacSynergy II program. dOTC in combination with 3TC or d4T showed a moderate synergistic effect while all other combinations had an additive interaction.
Anti-HIV Agents↗
A putative alternatively spliced variant of the P2X(1) purinoreceptor in human bladder.
Activation of purinergic P2X receptors, putatively P2X1, may be important in the initiation of contraction in human detrusor. Purinergic transmission may be more important in muscle taken from patients with bladder instability. In this study the presence of the P2X1 receptor subtype was confirmed using RT-PCR. In addition, the results indicate, at the mRNA level, the presence of a splice variant of P2X1 that is lacking part of the second transmembrane domain. It is therefore possible that human bladder expresses multiple isoforms of the P2X1 receptor which may be potential sites for modifying or regulating putative purinergic activation of the human bladder.
Alternative Splicing↗
Focal changes in nerve, muscle and connective tissue in normal and unstable human bladder.
OBJECTIVE: To compare and quantify, in a morphological study, the changes that occur in the connective tissue elements (elastin and collagen), muscle fibre diameters and nerve densities between normal, idiopathic and neuropathic bladders. MATERIALS AND METHODS: Bladder tissue was obtained from 27 patients undergoing cystectomy for carcinoma, from 12 with idiopathic instability and from seven neuropathic patients who were undergoing ileocystoplasty. A combination of histochemical and immunohistochemical techniques were used to detect detrusor muscle, connective tissue and nerve profiles in the bladder tissue. RESULTS: In both idiopathic and neuropathic bladder tissue the structural changes were highly punctate. From the density of nerve profiles, three areas were defined: (i) apparently unaffected normal fascicles with a high density of nerves, no hypertrophy of the muscle and no infiltration of elastin and collagen. The nerve density in these areas was similar to that in normal bladder tissue. (ii) Fascicles with a low density of nerve profiles, muscle hypertrophy but no connective tissue infiltration. (iii) Areas with few nerve profiles, muscle hypertrophy and extensive elastin and collagen infiltration within the fascicles. The mean (sem) density of nerve profiles in control tissue was 752 (53) nerves/mm2 and in the idiopathic bladders was 905 (91), 81 (20) and 74 (38) nerves/mm2 in the three defined areas, respectively. In the neuropathic tissues the nerve profile densities were 672 (249), 57 (23) and 37 (28) nerves/mm2, respectively. Fibre diameter, elastin and collagen content and nerve density were measured in normal and unstable bladder tissue using these three defined areas. The mean (sem) fibre diameter was 6.81 (0.52) in normal bladder; in idiopathic bladder tissue the fibre diameters in the three areas were 6.72 (0.62), 7.06 (0.62) and 7.34 (1.15) micrometer, respectively, and in neuropathic bladders were 6.75 (0.62), 8.24 (0.62) and 9.35 (0.62) micrometer, respectively. The relative areas of elastin were 0.79 (0.70), 0.56 (0.45) and 18.3 (4.1)% for the control, normal and affected areas of the neuropathic bladders, respectively, and the relative areas of collagen were 3.5 (1.3), 6.15 (3.6) and 15.7 (5. 0)%, respectively. The pattern was similar in idiopathic bladders. CONCLUSION: These observations suggest that the primary defect in the idiopathic and neuropathic bladders is a loss of nerves accompanied by a hypertrophy of the cells. These changes may continue with further hypertrophy of the cells and an increased production of elastin and collagen within the muscle fascicles.
Connective Tissue Diseases↗
Detection and characterization of proteins encoded by the second ORF of the M2 gene of pneumoviruses.
The nucleotide sequence of the M2 gene of pneumonia virus of mice (PVM) was determined. The sequence showed that the gene encoded a protein of 176 amino acids with a predicted molecular mass of 20165 Da from a major ORF, which is smaller than the equivalent proteins encoded by human, bovine and ovine respiratory syncytial (RS) viruses. The PVM M2 protein is conserved, having 41% similarity to the equivalent human RS virus protein. In common with the M2 genes of the RS viruses and avian pneumovirus (APV), the PVM mRNA also contained a second ORF (ORF2) that partially overlaps the first ORF and which is capable of encoding a 98 residue polypeptide. No significant sequence identity could be detected between the putative M2 ORF2 proteins of PVM, APV and the RS viruses. The expression of the M2 ORF2 proteins of the pneumoviruses was investigated by using monospecific antisera raised against GST fusion proteins. Western blot analysis demonstrated the presence of polypeptides encoded by M2 ORF2 of PVM and RS virus corresponding with those predicted by in vitro translation studies, but this was not the case for APV. The PVM polypeptide was present as three distinct products in vivo. The PVM and RS virus polypeptides were also detected in cells by immunofluorescence, which showed that both were present in the cytoplasm with a degree of localization in inclusion bodies. No APV M2 ORF2 protein could be detected in vivo. The RS virus M2 ORF2 polypeptide was shown to accumulate during infection and the potential implications of this are discussed.
Amino Acid Sequence↗
Familial risk estimation in systemic sclerosis.
BACKGROUND: Familial systemic sclerosis has been rarely reported. Assumptions have therefore been made implying no familial disease aggregation. This study critically challenges the assumption using a methodical population-based epidemiological approach to quantify the prevalence and characteristics of familial systemic sclerosis. METHODS: In this retrospective cohort study the systemic sclerosis prevalence in first degree family members was compared between 715 systemic sclerosis patients (710 families) and 371 randomly ascertained age and gender group-matched general practice controls (371 families). These data, obtained by telephone questionnaire (living patients) or medical records review (deceased patients and untraceable patients of unknown living status), were validated, where necessary, and expressed in terms of relative risk, absolute risk and population point prevalence. RESULTS: Systemic sclerosis affecting first degree members was validated in ten of 710 families. Reporting of systemic disease in another four more distant family members, and the co-occurrence of systemic and localised disease in three families was also documented. Observed and expected disease subtype concordance was 80% (44-97%) and 68% respectively and the female predominance among familial cases was similar to that for non-familial disease. The risk of disease in a subsequent first degree relative was compared to the risk in an initial first degree family member. Its estimated magnitude was wide (11-158). However, use of population prevalence data to determine the expected number of systemic sclerosis patients in the negative cohorts' families suggests the higher estimate is more realistic. Despite the high magnitude, the absolute disease risk in first degree family members remained low--approximating 1%. The population prevalence of familial systemic sclerosis approximated 1.4/million. CONCLUSIONS: This study substantially increases the otherwise small list of documented instances of familial systemic sclerosis. More importantly, it quantifies the risk for the first time, ranking it as the disease's most powerful determinant identified to date.
Cohort Studies↗
Systemic sclerosis prevalence and mortality in Sydney 1974-88.
BACKGROUND: Systemic sclerosis prevalence and mortality estimates have demonstrated wide variability. The sole Australian study published to date demonstrated high prevalence rates when compared to overseas estimates. The prevalence and mortality findings reported in this paper derive from a larger study which addressed the distribution and determinants of systemic sclerosis within Sydney. AIMS: To determine systemic sclerosis prevalence and mortality rates within Sydney over 15 years, 1974-88. METHODS: Cases were ascertained from multiple sources including death certificates, hospitals, physicians, vascular surgeons' and dermatologists' private practices, a systemic sclerosis self-help group and private medical laboratories. RESULTS: Overall, 715 cases were identified. Females comprised 77% (95% CI: 74-80) of cases. Disease of the limited subtype accounted for 79% (95% CI: 76-82) of all systemic sclerosis, being relatively more frequent in living than deceased cases, and in females than males. Crude prevalence estimates appeared to rise between 1975 (4.52/100,000 95% CI:3.75-5.29/100,000) and 1988 (8.62/100,000 95% CI:7.64-9.60/100,000) as did estimates of diffuse disease. However, diffuse disease prevalence, when expressed as a proportion of total disease prevalence, showed no significant temporal change. Although crude mortality rates also showed apparent temporal increases (0.24/100,000 in 1975 to 0.80/100,000 in 1988) standardised mortality rates showed less convincing trends (0.41/100,000 in 1976 and 0.40/100,000 in 1988). Death certificate-derived mortality rates provided relatively large underestimates of total mortality. However, these underestimates were relatively constant over time. CONCLUSIONS: This study has demonstrated systemic sclerosis prevalence and mortality rates comparable to overseas estimates, consistently higher prevalence and mortality rates in females than males, proportionally higher rates of diffuse disease in males than females and in deceased cases than living cases, a diffuse: limited disease ratio apparently stable over time, apparently increasing temporal prevalence and mortality rates and, by implication, rising incidence rates. The observed temporal rise in diffuse disease prevalence and the absence of a convincing fall in diffuse disease mortality suggests a rising temporal incidence rate of diffuse disease. Standardised mortality rates demonstrated less consistent trends than did crude mortality rates and failed to demonstrate convincing declines in mortality subsequent to the introduction of ACE inhibitors for management of systemic sclerosis renal disease. Death certificate-derived systemic sclerosis mortality rates considerably and consistently underestimated systemic sclerosis-all cause mortality.
Data Collection↗
Ryanodine receptors in human bladder smooth muscle.
The role of intracellular Ca2+ release in the activation of human bladder smooth muscle is controversial. We have measured the expression of mRNA encoding for the ryanodine receptor (RyR) isoforms (RyR1, RyR2 and RyR3) in isolated human detrusor smooth muscle. mRNA for RyR2 was detected in all samples but no mRNA for RyR1 or RyR3 could be found. Human bladder smooth muscle cells in culture are unresponsive to caffeine, suggesting the absence of a functional RyR system. However, mRNA encoding for RyR2 was detected in these cells. Using saponin-permeabilized cells, a Ruthenium Red-sensitive Ca(2+)-dependent 45Ca2+ release could be demonstrated from the sarcoplasmic reticulum (SR). These data confirm the functional presence of Ca(2+)-induced Ca2+ release (CICR) in cells and suggest that the properties of the RyR2 isoform in human detrusor may change when the cells are maintained in culture. The implications of these observations to detrusor smooth muscle function are discussed.
Calcium↗
Pyrido [1,2a] indole derivatives identified as novel non-nucleoside reverse transcriptase inhibitors of human immunodeficiency virus type 1.
Pyrido [1,2a] indole derivatives were identified as potent inhibitors of human immunodeficiency virus type 1 (HIV-1) replication during a random screening programme. The compounds showed no antiviral activity against HIV-2 or in cells chronically infected with HIV-1, but had good inhibitory effect against purified HIV-1 reverse transcriptase (RT) in an in vitro assay. They were therefore classified as non-nucleoside RT inhibitors (NNRTI). The synthesis of additional compounds of the same class revealed a structure-activity relationship. The most potent compound of the series, BCH-1, had similar antiviral activity to the licensed NNRTI nevirapine against laboratory strains of HIV-1 cultured in cell lines and primary clinical isolates of HIV-1 cultured in peripheral blood mononuclear cells. However, BCH-1 showed greater cytotoxicity, providing a narrow selectivity index in the order of 35. BCH-1 had equivalent antiviral activity against viruses resistant to the nucleoside RT inhibitors zidovudine, didanosine and lamivudine and maintained better activity (less than threefold change in IC50) than nevirapine against viruses resistant to a range of NNRTIs with the single amino acid changes L100I, K103N, E138K or Y181C in the RT. Viruses with single V106A or Y188C amino acid changes showed five- and 10-fold resistance to BCH-1, respectively, in contrast to nevirapine, which had a > 100-fold change in IC50. However, virus with both V106A and Y188C amino acid changes showed higher level resistance (> 15-fold) to BCH-1. Virus with > 10-fold resistance to BCH-1 was rapidly selected for after growth in increasing concentrations of compound and was shown to be cross-resistant to nevirapine. Sequencing of this virus revealed two amino acid changes at positions 179 (V to D) and 181 (Y to C) in the RT. BCH-1 represents a new class of NNRTI, which may act as a lead to identify more selective compounds.
Amino Acid Substitution↗
Nucleotide sequence of the genes encoding the matrix and small hydrophobic proteins of pneumonia virus of mice.
The nucleotide sequences of the genes encoding the matrix (M) protein and the small hydrophobic (SH) protein of pneumonia virus of mice (PVM) are described. The matrix protein gene contains a large open reading frame encoding polypeptide of 257 residues which shows considerable (38.6-42.1%) amino acid identity with the matrix proteins of other pneumoviruses. The matrix gene also contains a second, smaller, open reading frame (ORF) as seen with the equivalent genes of other pneumoviruses. The PVM second open reading frame is capable of encoding a polypeptide of 46 residues and shows no significant similarity with the proteins encoded by the equivalent open reading frames of the other pneumoviruses. The gene adjacent to that encoding the matrix protein encodes a small, 92 residue, polypeptide which has a central hydrophobic domain and is structurally similar to the small hydrophobic protein of respiratory syncytial virus.
Amino Acid Sequence↗