Biomedical subjects
Publications and source records attributed to J Parsons.
Investigation of furans, pyrroles and pyrazolones identified 3-pyridyl-2,5-diaryl-pyrroles as potent, orally bioavailable inhibitors of p38 kinase. 3-(4-pyridyl-2-(4-fluoro-phenyl)-5-(4-methylsulfinylphenyl)-pyrrol e (L-167307) reduces secondary paw swelling in the rat adjuvant arthritis model: ID50 = 7.4 mg/kg/b.i.d.
The serine/threonine kinase p38 is a ubiquitous, highly conserved, stress responsive, signal-transducing enzyme. It regulates the production of proinflammatory mediators and is the target of the cytokine synthesis inhibitory pyridinylimidazoles. We have expressed human p38 in Drosophila S2 cells and characterized preparations of mixed unphosphorylated/monophosphorylated (inactive) and homogeneously diphosphorylated (active) forms of the enzyme. We observed that only the active preparation of the enzyme has significant kinase activity when assayed using an ATF2-GST fusion protein as the substrate. We determined that the value of KM[ATP] in this reaction is 25 microM and that the pyridinylimidazole inhibitor of p38 kinase activity, SB203580, competes with ATP. We have found that a tritiated pyridinylimidazole, SB202190, has an equal affinity for both the active and inactive forms of the enzyme and that SB203580 competes with it equally well for binding to either form of the enzyme. However, ATP can compete with the tritiated inhibitor for binding to only the active form of the enzyme. Further, we demonstrate in vivo that at concentrations consistent with its IC50 as a cytokine inhibitor, SB203580 can inhibit stimulus-induced phosphorylation of p38 at the Thr-Gly-Tyr activation motif. Our observations suggest that pyridinylimidazoles may block the biological activity of p38 kinase by binding to the inactive form of p38 and reducing its rate of activation. Under these conditions, ATP would not effectively compete with the inhibitors in vivo.
BACKGROUND: This study aimed to explore the relationship between complications and risk factors in the type 2 diabetes population, and to assess the level of assistance people with diabetes receive in controlling their risk factors. METHODS: Participants were recruited from representative population surveys of South Australians aged over 18 years. Participants were asked a series of questions about their risk factors and the advice and assistance they received from their general practitioner (GP) in modifying their risk factors. Additionally, participants were clinically tested for a number of macro and microvascular complications. RESULTS: South Australians with type 2 diabetes have a high prevalence of risk factors, with the majority being overweight or obese, doing no vigorous exercise and having high blood pressure. They also have a high prevalence of complications, with 53% having at least one macrovascular complication and 66% having at least one microvascular complication. Additionally, participants reported high levels of GP advice and assistance on the risk factors where pharmacological controls were available, but low levels of assistance where non-pharmacological interventions were needed to control the risk factor. CONCLUSIONS: The prevalence of diabetes risk factors and complications among South Australians with type 2 diabetes is a cause for concern, as is the lack of assistance offered by GPs to modify risk factors. Multi-disciplinary approaches to the control of risk factors and patient self-management and education are critical to the progression and success of diabetes care.
OBJECTIVE: To assess the presence and outcome of Doppler detectable shunts following implantation of the Cook detachable PDA coil. DESIGN: Prospective study. SETTING: Tertiary paediatric cardiac centre. PATIENTS: 76 consecutive patients undergoing coil implantation (80 procedures). MAIN OUTCOME MEASURES: Detection and colour Doppler echocardiographic appearance of residual or recurrent shunts, the timing of the appearance of recurrent shunts, and the time taken for spontaneous resolution of these shunts. RESULTS: Immediate occlusion was achieved in 52 patients. At one month 63 patients had complete occlusion and after three months the duct was completely occluded in 67 patients. In 27 cases small residual shunts were detected on echocardiography 10 minutes after the completion of the implantation procedure; 15 of these had resolved by 24 hours and 20 had resolved by three months. Recurrent shunts were detected after apparent initial complete occlusion in 11 cases 24 hours after coil implantation and in two cases one month after the procedure. Six recurrent shunts resolved on later follow up. Residual shunts appeared as single jets after implantation of a single coil, but up to three separate jets were detected after implantation of multiple coils. CONCLUSIONS: Spontaneous resolution of small residual shunts occurs in most patients. The recurrence of small shunts after apparent complete occlusion suggests that recanalisation of the duct may occur in a small percentage of patients up to one month after occlusion. Residual shunts may take the form of multiple residual jets that may require implantation of further coils to achieve complete duct occlusion.
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Modern surgeons have at their disposal a vast array of advanced technological data dissemination devices. The ring of high resolution monitors circling the typical operating area to display pre-operative and real-time patient data is esteemly supportive. The drawback, however, is that such displays require the surgeons to frequently shift their head and gaze away from the principle field of interest. We describe a new display technique that provides surgeons with a lightweight, wearable display surface that permits localization of medical data of main interest near the field of operation with minimal head and gaze movements.
Focal adhesion kinase (pp125(FAK)) is a protein tyrosine kinase that is localized to focal adhesions in many cell types and which undergoes tyrosine phosphorylation after integrin binding to extracellular matrix. In some cells the C-terminal non-catalytic domain of pp125(FAK) is expressed as a separate protein referred to as FRNK (FAK-related, non-kinase). We have previously shown that overexpression of FRNK inhibits tyrosine phosphorylation of pp125(FAK) and its substrates as well as inhibiting cell spreading on fibronectin. In this report we identify Ser148 and Ser151 as residues in FRNK that are phosphorylated after tyrosine phosphorylation of pp125(FAK) and in response to integrin binding to fibronectin. Tyrosine phosphorylation of pp125(FAK) appears to be an early event after integrin occupancy, and serine phosphorylation of FRNK occurs significantly later. Treatment of fibroblasts with a series of protein kinase A inhibitors delayed serine phosphorylation of FRNK as well as cell spreading on fibronectin and tyrosine phosphorylation of pp125(FAK). However, these PKA inhibitors are unlikely to delay cell spreading simply by preventing serine phosphorylation of FRNK, as overexpression of FRNK containing mutations of Ser148 and Ser151 either singly or jointly to either alanine or glutamate residues did not significantly alter the ability of FRNK to act as an inhibitor of pp125(FAK).
The ability of commercially available PCR-based assays to accurately detect or quantitate human immunodeficiency virus type 1 (HIV-1) DNA or RNA in individuals predominantly infected with HIV-1 subtypes A and D is not known. Therefore, peripheral leukocytes from 43 individuals in Kampala, Uganda, positive for HIV by the Western blot (immunoblot) assay were tested by using the Roche AMPLICOR HIV-1 assay for the detection of DNA gag sequences. Plasma from these same individuals was tested by using the Roche HIV-1 AMPLICOR MONITOR HIV-1 assay for the quantitation of HIV-1 RNA gag sequences. In addition, peripheral leukocytes were tested for HIV-1 DNA by using a lower annealing temperature or a different primer pair for the HIV-1 pol region. The proportions of individuals with detectable HIV-1 DNA and RNA gag sequences by the Roche assays were 74 and 90%, respectively. The proportions positive for HIV-1 DNA sequences by using a 50 degrees C annealing temperature or the pol primer pair were 71 and 98%, respectively. In summary, the standard Roche assay did not detect HIV-1 DNA sequences in a significant number of HIV-1-infected individuals in Uganda. However, use of a pol primer pair increased the sensitivity of the assay to 98%. The sensitivity of the Roche AMPLICOR MONITOR assay for the detection and quantitation of HIV-1 RNA sequences was significantly higher than that of the DNA-based assay, but the efficiency of the assay, and hence, the accuracy of the values obtained with RNA, is not known. Modifications to existing assays are needed to enhance the sensitivities and accuracies of these commercially available assays for use in developing countries where non-B HIV-1 subtypes predominate.
Eosinophils have long been thought to be effectors of immunity to helminths but have also been implicated in the pathogenesis of asthma. Patterns of cytokine production in the host may influence the pathogenesis of these diseases by regulating the activities of eosinophils and other components of the immune response. Mice which constitutively over-express IL-5 have profound and life-long eosinophilia in a restricted number of tissues. Although eosinophils from IL-5 transgenics are functionally competent for a number of parameters considered to be important in inflammation, untreated animals are overtly normal and free of disease. In addition, the responses of these animals when exposed to aeroallergens and helminths present a number of apparent paradoxes. Eosinophil accumulation in tissues adjacent to major airways is rapid and extensive in transgenics exposed to the aeroallergen, but even after treatment with antigen over many months these mice show no evidence of respiratory distress or pathology. Helminth-infected IL-5 transgenics and their non-transgenic littermates develop similar inflammatory responses at mucosal sites and are comparable for a number of T cell and antibody responses, but they differ considerably in their ability to clear some parasite species. The life-cycle of Nippostrongylus brasiliensis is significantly inhibited in IL-5 transgenics, but that of Toxocara canis is not. Our results also suggest that eosinophilia and/or over-expression of IL-5 may actually impair host resistance to Schistosoma mansoni and Trichinella spiralis. The pathogenesis of diseases in which eosinophils are involved may therefore be more complex than previously thought.
Distinctions between chemotaxis and haptotaxis of cells to extracellular matrix proteins have not been defined in terms of mechanisms or signaling pathways. Migration of A2058 human melanoma cells to soluble (chemotaxis) and substratum-bound (haptotaxis) vitronectin, mediated by alphav beta3, provided a system with which to address these questions. Both chemotaxis and haptotaxis were completely inhibited by treatment with RGD-containing peptides. Chemotaxis was abolished by a blocking antibody to alphavbeta3 (LM609), whereas haptotaxis was inhibited only by approximately 50%, suggesting involvement of multiple receptors and/or signaling pathways. However, blocking antibodies to alphavbeta5, also present on A2058 cells, did not inhibit. Pertussis toxin treatment of cells inhibited chemotaxis by >80%, but did not inhibit haptotaxis. Adhesion and spreading over vitronectin induced the phosphorylation of paxillin on tyrosine. In cells migrating over substratum-bound vitronectin, tyrosine phosphorylation of paxillin increased 5-fold between 45 min and 5 h. Dilutions of anti- alphavbeta3 that inhibited haptotaxis also inhibited phosphorylation of paxillin (by approximately 50%) and modestly reduced cell spreading. In contrast, soluble vitronectin (50-100 microg/ml) did not induce tyrosine phosphorylation of paxillin. The data suggest that soluble vitronectin stimulates chemotaxis predominantly through a G protein-mediated pathway that is functionally linked to alphavbeta3. Haptotaxis is analogous to directional cell spreading and requires alphavbeta3-mediated tyrosine phosphorylation of paxillin.
OBJECTIVE: To determine whether the use of smaller diameter needles at oocyte collection reduces pain without jeopardizing the treatment outcome. DESIGN: Prospective randomized study. SETTING: The Assisted Conception Unit, Kings College Hospital, United Kingdom. PATIENTS: One hundred twelve patients undergoing an IVF-ET treatment cycle. INTERVENTIONS: Study patients were aged < or = 38 years and had at least six follicles > 14 mm on the day of oocyte collection. Patients were randomized to follicle aspiration with a 15- (n = 34), 17- (n = 41), or 18- (n = 37) gauge (g) single channel needle. Intravenous pethidine and diazepam were used for analgesia and sedation. Pain was quantified by means of questionnaires completed by the patient and by her partner postoperatively. RESULTS: A greater proportion of patients reported severe to unbearable pain with the 15-gauge compared with the 17-gauge (44% versus 22%) or 18-gauge (44% versus 16%) needles. Partners' perception of severe pain experienced by patients showed the same trend when the 15-gauge was compared with the 17- (62% versus 29%) and 18-gauge (62% versus 22%) needles. There was no significant difference between the needles regarding the oocyte collection rate, fertilization rate, proportion of oocytes with fractured zonae, cleavage rate, implantation rate, and pregnancy rate per cycle. CONCLUSIONS: Reducing the size of the needle used for oocyte collection from 15 to 17 or 18 gauge reduces pain without affecting the number of oocytes collected, their quality, or the clinical pregnancy rate.
The aim of this study was to elucidate possible relationships between ultrasound indices of follicular blood flow, oocyte recovery and the subsequent production and morphological quality of preimplantation embryos. A total of 27 women with bilateral tubal occlusion, undergoing treatment for infertility by in-vitro fertilization and embryo transfer, contributed data from 29 cycles. Transvaginal ultrasonography with colour Doppler imaging and pulsed Doppler spectral analysis was used to obtain indices of blood flow for each follicle immediately before it was aspirated. The main outcome measures for each follicle were the pulsatility index, peak systolic velocity, recovery or non-recovery of an oocyte and the subsequent production or non-production of an embryo. A total of 126 follicles were studied, 102 oocytes were recovered and 58 embryos (49 at grades I or II) were produced. There were six clinical pregnancies (pregnancy rate 27.3% per embryo transfer, 22.2% per patient). There was a significant correlation (P < 0.0001, chi2 test) between whether or not follicular blood flow was detected and whether or not an oocyte was recovered. The sensitivity of a test based on the presence of detectable blood flow and the subsequent recovery of an oocyte was 74% and the positive predictive value was 93%. The peak systolic velocity (PSV, measured in cm/s, mean +/- SD) in follicles with detectable blood flow was significantly higher in follicles that were associated with the production of a preimplantation embryo (19.7 +/- 10.8) compared with those that were not (9.9 +/- 5.3, P < 0.0001, Student's t-test). There was a 70% chance of producing a grade I or II embryo if the follicular blood velocity was >/=10 cm/s, compared with 14% if the PSV was <10 cm/s, or 18% if no blood flow was detected. We conclude that there is a physiological relationship between follicular blood velocity, oocyte recovery and the production of a high-grade preimplantation embryo, which may form the basis of a useful clinical test.
This study was carried out to investigate whether ovarian cystectomy interferes with follicular recruitment and the number of oocytes retrieved in an in-vitro fertilization (IVF) cycle. Patients who had previously undergone unilateral ovarian cystectomy (n = 90) and control patients (n = 90) with no history of ovarian surgery were included in our study. The parameters compared were the number of follicles recruited and the number of oocytes obtained from each ovary. In patients who had undergone surgery, the normal ovaries recruited a significantly higher number of follicles (P < 0.001) and yielded a significantly higher number of oocytes (P < 0.001) compared with the contralateral ovaries which had undergone cystectomy. In the control patients, no significant differences were identified between the left and right ovaries. These results demonstrate that ovarian cystectomy reduces follicle and oocyte numbers in ovulation induction cycles.
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We report the generation of 319,311 single-pass sequencing reactions (known as expressed sequence tags, or ESTs) obtained from the 5' and 3' ends of 194,031 human cDNA clones. Our goal has been to obtain tag sequences from many different genes and to deposit these in the publicly accessible Data Base for Expressed Sequence Tags. Highly efficient automatic screening of the data allows deposition of the annotated sequences without delay. Sequences have been generated from 26 oligo(dT) primed directionally cloned libraries, of which 18 were normalized. The libraries were constructed using mRNA isolated from 17 different tissues representing three developmental states. Comparisons of a subset of our data with nonredundant human mRNA and protein data bases show that the ESTs represent many known sequences and contain many that are novel. Analysis of protein families using Hidden Markov Models confirms this observation and supports the contention that although normalization reduces significantly the relative abundance of redundant cDNA clones, it does not result in the complete removal of members of gene families.
OBJECTIVE: To evaluate the clinical utility of maternal HIV-1 RNA serum levels at delivery in predicting the rate of HIV-1 vertical transmission. DESIGN AND METHODS: HIV-1 RNA levels were determined by the Roche Amplicor Monitor assay in serum specimens collected at the time of delivery from 94 transmitting and 107 nontransmitting infected mothers and 12 seronegative mothers in Uganda. Nonparametric Wilcoxon-Rank sum tests were used to identify significant differences in medians and RNA level distributions by transmission status. RESULTS: Mean HIV-1 RNA copies/mL for transmitters was 3419 +/- 7489 copies/mL versus 2483 +/- 8954 copies/mL for nontransmitters. There was a significant difference in medians and HIV-1 RNA serum level distributions between transmitting and nontransmitting mothers (p = 0.0039). However, the predictive value for any given HIV-1 RNA level for HIV-1 vertical transmission was poor. CONCLUSION: Maternal HIV-1 RNA serum levels at delivery are significantly higher in transmitting mothers versus nontransmitting mothers, but appear to be of limited value in predicting HIV-1 vertical transmission using the Roche Amplicor Monitor assay in Uganda.
PURPOSE: To examine the patterns, facilitators, and barriers to disclosure of HIV seropositivity in an adolescent population and to determine the relationship between disclosure and condom use. BACKGROUND: In recent years, public health efforts have focused on methods to prevent the transmission of the Human Immunodeficiency Virus (HIV). These efforts have included safer sex education, skill building and self-efficacy training, behavioral change techniques, and encouragement of serostatus disclosure to sexual partners. In 1990, the Centers for Disease Control and Prevention (CDC) funded 10 hemophilia treatment centers to develop and implement a theory-based behavioral intervention to prevent the sexual transmission of HIV. METHODS: A baseline survey, focusing on barriers to safer sex, the influence of parents, peers, and sexual partners, alcohol and drug use, and communication and disclosure patterns, was administered to 321 young males (ages 12 to 25) with hemophilia and HIV. RESULTS: Fifty-eight percent of the sexually experienced adolescents did not disclose their HIV status to their most recent sexual partners (i.e., nondisclosers) compared to 42 percent who reported that either they informed their partners or their partners already knew their HIV status (i.e., disclosers). There was no correlation between disclosure and condom use. The most significant predictor of disclosure was the perception that peers would disclose their HIV status. CONCLUSION: The results suggest that disclosure does not necessarily facilitate condom use in this population. This conclusion may have implications for future public health efforts in HIV prevention. Rather than focusing primarily on the promotion of serostatus disclosure, behavioral interventions should emphasize the practice of safer sex, utilizing peer educators and support networks.
OBJECTIVE: To determine the correlation between the detection of human immunodeficiency virus type 1 (HIV-1) in breast milk, the duration of breastfeeding, and vertical transmission of HIV-1 infection in Ugandan women. METHODS: A prospective study of HIV-1 infection in pregnant Ugandan women and their infants has been ongoing since 1990 with follow-up of mother-infant pairs for at least 2 years. Expressed breast milk specimens were collected from 201 HIV-1-seropositive and 86 HIV-1-seronegative Ugandan women approximately 6 weeks after delivery. The presence of HIV-1 DNA in the cellular fraction of the breast milk was detected by polymerase chain reaction (PCR), and HIV-1 p24 antigen was detected in the cell-free breast milk supernatant using p24 antigen enzyme immunoassay (EIA) after immune complex dissociation (ICD). The duration of breastfeeding and the clinical status of the mothers and their children were recorded. HIV-1 EIA, Western blot, PCR, or p24 antigen detection were used for the determination of the HIV-1 infection status of the children. RESULTS: Of the 201 HIV-1-infected women studied, 47 had HIV-1-infected children, 143 had children who seroreverted, and 11 had children of indeterminate status. Breast milk supernatants were available for ICD p24 antigen testing from 188 of the HIV-1-infected women and none had detectable p24 antigen. Breast milk cell pellets were available and contained amplifiable DNA in 125 of the HIV-1-infected women (20 transmitters, 104 nontransmitters, 1 indeterminate). HIV-1 DNA was detected by PCR in 72% (75/104) of nontransmitters and 80% (16/20) of the transmitters. The duration of breastfeeding by transmitter mothers (15.8 months) was not significantly different from nontransmitter mothers (14.4 months). CONCLUSIONS: No correlation was found between the detection of HIV-1 in breast milk or the duration of breastfeeding and transmission of HIV-1 infection in this study of Ugandan women.