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Biomedical subjects

H Jones

Publications and source records attributed to H Jones.

At least 37 records · Page 2Linked to original sources

A randomised controlled trial comparing Drawtex with standard dressings for exuding wounds.

OBJECTIVE: This randomised controlled clinical trial compared a capillary dressing (Drawtex, now rebranded as Vibriant RCD [Vibriant Technology Services]) with routine practice for exuding wounds greater than 2.5 x 2.5 cm. METHOD: The target population was 300 control and 300 test subjects across three sites in the UK, but recruitment difficulties resulted in only 125 patients being evaluable. Wound progress was recorded by nurses' perception of the progress of wound healing and by objective digital imaging. In the final analysis digital images were randomised (in time order) and a panel of nurses who were not otherwise involved in the research project graded the wound's progress. RESULTS: After deconvolution of the data, the subjective (nurse perception) method of evaluation determined that the new dressing resulted in wound improvement in 12.7% more patients than did routine practice, but the blinded assessment method (based on the digital images) showed that routine practice was better by 6.6%. CONCLUSION: Evaluation of wound progress is clearly difficult. Human nature makes us favour novelty if we believe it is going to be better. Making interpretation more objective removed that bias and did not demonstrate a significant advantage for the test dressing. The findings suggest that unblinded assessment by trial nurses is unacceptable on its own. Blinded assessments may miss finer nuances of wound progression, but are likely to be more accurate. The authors suggest that the true result lies somewhere in the middle, with the trial dressing likely to be as effective as, but not more effective than, a standard dressing.

Aged↗

The effect of oral folic acid on glutathione, glycaemia and lipids in Type 2 diabetes.

Plasma homocysteine is an established risk factor for vascular disease and precursor of the anti-oxidant glutathione. This study was designed to investigate the relationship of changes in homocysteine (Hcy) induced by oral folate to glutathione and measures of glycaemia and lipid metabolism in Type 2 diabetes (T2DM). Twenty-seven patients (26 male, 1 female, aged 48-68 years) with T2DM and microalbuminuria were treated with folic acid 10 mg daily for 3 months. During the study, diastolic blood pressure (p=0.04), HbA1c (p=0.04), serum triglycerides (p=0.04) and serum total/HDL-cholesterol ratio (p=0.004) all increased and serum HDL-cholesterol fell (p=0.006). The increased red cell folate correlated with a reduction in microalbuminuria (p=0.001). Overall, plasma glutathione increased (p=0.016) despite reduction in its precursor Hcy (p<0.001). Change in glutathione correlated inversely with change in HbA1c (p<0.02), total cholesterol (p=0.003) and triglycerides (p<0.02) and positively with HDL-cholesterol (p=0.033). Increase in glutathione correlated with levels of vitamin B6 (p<0.05). Metformin treatment protected against the rise in blood pressure (BP) (p=0.02), independently of changes in plasma glutathione. In summary, oral folic acid supplementation in T2DM reduced plasma Hcy and increased glutathione levels. HbA1c, triglycerides and HDL-cholesterol deteriorated during the trial: their levels correlated inversely with changes in glutathione. The increase in glutathione may depend on an adequate supply of B6, as changes in glutathione correlated with vitamin B6 levels. Reduced Hcy and increased glutathione may both mediate improvement in vascular function and outcome. Some aspects of the response to folate may be different in patients on metformin.

Adult↗

Internet use by patients with prostate cancer undergoing radiotherapy.

OBJECTIVES: To analyze the amount of Internet use, type of Internet use, and factors that predict Internet use by patients with prostate cancer. METHODS: A questionnaire evaluating the use of the Internet was given to 295 patients undergoing radiotherapy for prostate cancer in three different settings: an academic center (AC), a Veterans Affairs center (VA), and a community hospital. The study included 171 AC patients (58%), 104 VA patients (35%), and 20 community hospital patients (7%). RESULTS: The response rate to the questionnaire was greater than 99%. Overall, 128 (43%) of 295 patients had a home computer. This differed among the institutions, with 64% of AC patients and only 5% of VA patients having a home computer (P <0.0001). Overall, 94 (32%) of 295 patients used the Internet to access cancer information, with 48% of AC patients and 8% of VA patients using the Internet (P <0.0001). Seventeen percent of black patients (n = 113) had a home computer compared with 62% of white patients (n = 175; P <0.0001). Equal access to computers did not influence Internet use because, among those patients who had access to computers, black patients used the Internet less than did white patients (32% versus 61%, P <0.0001). Men 65 years of age or younger were more likely to use the Internet (45%) than those older than 65 years (28%; P = 0.004). Patients used many sites to access different types of information. CONCLUSIONS: A significant number of patients with prostate cancer access the Internet to obtain cancer information. Urologists and radiation oncologists should be familiar with this important resource to help patients access appropriate material.

Academic Medical Centers↗

Heterosexual outbreak of infectious syphilis: epidemiological and ethnographic analysis and implications for control.

This study describes the epidemiology and ethnography of an outbreak of infectious syphilis in Vancouver, British Columbia. Between 1996 and 1999, British Columbias's rate of infectious syphilis rose from 0.5 to 3.4 per 100,000, with a dense concentration of cases among sex trade workers, their clients, and street-involved people in the downtown eastside area of Vancouver. Sexual networks were imported cases with secondary spread (dyads and triads), large densely connected dendritic networks of sex trade workers and clients, or occasional starburst networks among gay men. Only 232 of 429 partners were documented as having been treated (54% of those named, or 0.9 per case). The geographical and demographic concentration of this outbreak led to consideration of a programme of focused mass treatment with single dose azithromycin.

Adolescent↗

Task and postural factors are related to back pain in helicopter pilots.

BACKGROUND: A previous survey by Shear et al. revealed a high prevalence of back pain in Royal Navy helicopter aircrew, compared with controls. It was recommended that a second survey be undertaken, taking account of flying tasks and cockpit ergonomics. This was the purpose of the present investigation. METHOD: A questionnaire containing items on back pain and posture was circulated to all 246 acting pilots, with returns of 75%. The questionnaire sought information on pain in both the flying pilot and co-pilot/instructor roles. RESULTS: The 12-mo prevalence of back pain was 80%. Task-related back pain was greatest in instrument flying (72%) and least in the co-pilot and instructor roles (24%). Self-ratings of posture indicated that forward flexed trunk postures predominated in the flying roles and were most extreme in instrument flying. In non-flying roles, symmetrical, reclining postures were more often reported. No demographic or psychosocial variables were significantly related to back pain prevalence or disability. CONCLUSIONS: Much of the back pain experienced by helicopter pilots appears to be due to the posture needed to operate the cyclic and collective controls. In instrument flying, it is suggested that the visual demands of scanning the displays may exacerbate the pain by causing the pilot to lean further forward.

Aerospace Medicine↗

The elective use of the seven-cell NIR stent in coronary arteries < 2.75 mm in diameter: clinical and angiographic results at 6-month follow-up.

The outcome of interventional procedures has been improved by the use of coronary stents in vessels > 3.0 mm in diameter. We report a single-center prospective study of elective coronary stenting in 39 consecutive patients with de novo lesions and reference diameters < 2.75 mm. Seven-cell NIR stents were deployed with standard antiplatelet therapy, but without routine use of IIb/IIIa inhibitors or intravascular ultrasound. There was one case of acute stent thrombosis, but no cases of subacute thrombosis. The binary restenosis rate was 27.8% (10/36 lesions) and the target lesion revascularization rate was 19.4%. Symptoms improved markedly as judged by Canadian Cardiovascular Society and questionnaire scores and the use of antianginal therapy. This pilot study suggests that the elective use of coronary stents in vessels < 2.75 mm in diameter is safe with acceptable long-term results. A randomized trial comparing outcomes after stents and balloon angioplasty in small vessels is required.

Aged↗

Comparison of PDE 4 inhibitors, rolipram and SB 207499 (ariflo), in a rat model of pulmonary neutrophilia.

Using a rat model of lipopolysaccharide (LPS)-induced pulmonary inflammation, the antiinflammatory activity of SB 207499 was evaluated and compared to that of the prototypic type-4 phosphodiesterase (PDE4) inhibitor, rolipram. In dose-response experiments, we found that rats exposed to 10 microg or 100 microg of intratracheal (it) LPS developed a prominent pulmonary inflammation, due to a significant increase in the number of recoverable bronchoalveolar lavage neutrophils. The pulmonary neutrophilia, provoked by the challenge of 10 microg LPS/rat, was significant at 2 h, peaked by 16 h, declined thereafter but remained elevated for up to 48 h. Additionally, the exposure of rats to 10 microg LPS caused the local pulmonary production of TNF- alpha. In contrast to the cellular influx, TNF- alpha production peaked at 2 h and rapidly declined to negligible levels by 8 h. While low levels were detected, the levels of IL-1 beta in bronchoalveolar lavage did not significantly differ from saline challenged animals. Rats pretreated with rolipram or SB 207499, displayed dose-dependent inhibition of the LPS-induced pulmonary inflammation. Nevertheless, the pulmonary production of TNF- alpha and IL-1 beta was unaffected by either SB 207499 or rolipram. When provoked with the 10 microg dose of LPS, adrenalectomized rats produced a similar 24 h induction of pulmonary neutrophilia. Pretreatment of adrenalectomized rats with the PDE4 inhibitors showed similar inhibitory results to those obtained in normal rats. In summary, we have shown, using a rat model of LPS-induced pulmonary neutrophilic inflammation, that the inhibitory activities of rolipram or SB207499 are not linked to the production of TNF- alpha or the inhibition of IL-1 beta, and occur independently of endogenous catecholamine or corticosteroid release.

Adrenalectomy↗

First trimester surgical abortion practices: a survey of National Abortion Federation members.

The objective of this study was to survey first trimester surgical abortion practices of North American providers. A survey was mailed to the 310 active member clinics of the National Abortion Federation, the professional organization of abortion providers in North America. The 236 respondents (76%) comprising the study group provided approximately 30% and 33% of all first trimester abortions in the US and Canada, respectively. Of the 529 practitioners who perform most abortions at the clinics, 68% are obstetrician-gynecologists, and 18% are family physicians; 51% are at least 50 years old. The majority of respondents (156 of 236, 66%) confirm gestational age with ultrasonography. Of the 202 clinics that favor one method of anesthesia, 58% use local cervical block with or without oral pre-medication, 32% combine local anesthesia with intravenous sedation, and 10% use general anesthesia. Most clinics open the cervix with tapered dilators (207 of 233, 89%), evacuate the uterus by using curved rigid plastic cannulas (157 of 229, 69%) and an electric vacuum source (191 of 233, 82%), and explore the uterus with a metal curette following aspiration (133 of 232, 57%). A large majority of respondents examine the uterine aspirate on-site (91%), prescribe antibiotics (91%), and offer oral contraceptives (95%) when requested. Although variations exist, surgical techniques and postoperative practices are quite uniform among clinics. Local anesthesia is presently the most frequent method of pain control. Ultrasonographic dating before abortion is common practice. The "graying" of skilled practitioners raises concerns about the future availability of abortion.

Abortion, Legal↗

A comparison of allergen and polycation induced cutaneous responses in the rabbit.

Allergic inflammatory responses contribute to the symptoms of a number of diseases including atopic dermatitis, asthma and rhinitis. Cationic proteins are released from inflammatory cells and levels are known to be raised in disease states. Using an in vivo model of acute inflammation, we investigated the characteristics of cutaneous responses to antigen (Alternaria tenuis, AT) and poly-L-lysine (PLL, used as a paradigm for cationic proteins). We aimed to compare the inflammatory profile of cationic polypeptides and the allergic response and to identify similarities and differences between these responses. Responses to intradermal injection of the polycation, PLL and antigen were compared using radiolabelled protein ((125)I-bovine serum albumin, BSA) and cells ((111)In-neutrophils, PMN) to study plasma exudation (PE) and PMN accumulation (PMNA) in the skin of AT sensitized rabbits. Both PLL and antigen caused dose-related increases in PE and PMNA. PE (and PMNA) responses to PLL were prolonged (up to 3 h), as were those to antigen. This is in contrast to PE responses to fMLP which were maximal at 45 min. In immunized animals, treated with colchicine (1 mg kg(-1) i.v.), PE responses to the directly acting mediator, bradykinin (BK), were not affected, whereas PE responses to the neutrophil dependent mediator, f-met-leu-phe (fMLP), were significantly (P<0.01) reduced. Antigen-induced PE responses were significantly (50, 500 (P<0.05); 200 (P<0.01) p.n.u. site(-1)) inhibited by colchicine, but PLL-induced responses were not significantly affected. We conclude that although PLL-induced responses had a similar time course to those of antigen, some differences were observed between responses, which indicate that although polycations may contribute to allergic responses, these two responses are produced by distinct mechanisms.

Allergens↗

Expression of antisense SnRK1 protein kinase sequence causes abnormal pollen development and male sterility in transgenic barley.

A chimaeric gene was constructed comprising a wheat high molecular weight glutenin subunit gene promoter, a 304-bp sucrose non-fermenting-1-related (SnRK1) protein kinase sequence in the antisense orientation, and the cauliflower mosaic virus 35S RNA gene terminator. Transgenic barley plants containing the antisense SnRK1 chimaeric gene were produced by particle bombardment of barley immature embryos with the aim of obtaining plants expressing the antisense SnRK1 sequence in the seeds. Despite the fact that the promoter was expected to be active only in seeds, two independent transgenic lines were found to fail to transmit the transgene to the T1 generation. These T0 plants had matured and died before this was discovered, but subsequently four other independent transgenic lines were found to be affected in the same way. Cytological analysis of the pollen grains in these lines showed that about 50% were normal but the rest had arrested at the binucleate stage of development, were small, pear-shaped, contained little or no starch and were non-functional. The presence of antisense SnRK1 transcripts was detected in the anthers of the four lines analyzed and a ubiquitin promoter/UidA (Gus) gene, one of the marker genes codelivered with the antisense gene, was found to be expressed only in the abnormal pollen. Expression analyses confirmed that SnRK1 is expressed in barley anthers and that expression of one class of SnRK1 transcripts (SnRK1b) was reduced in the abnormal lines. All of the abnormal lines showed approximately 50% seed set, and none of the transgenes were detected in the T1 generation.

Cell Differentiation↗

Hypoalbuminemia and proteinuria contribute separately to reduced lipoprotein catabolism in the nephrotic syndrome.

BACKGROUND: Hypertriglyceridemia is a result of reduced triglyceride (TG)-rich lipoprotein (TRL) catabolism and occurs in rats with nephrotic syndrome (NS) and in Nagase analbuminemic rats (NARs). While the heparin-releasable lipoprotein lipase (LpL) pool in NAR and in NS is similar, TG levels are significantly greater in NS, suggesting that factors other than reduced LpL alone act in NS but not in NARs. Furthermore, clearance of chylomicrons (CM) and very low-density lipoprotein (VLDL) is normal in vivo in NAR despite low LpL levels. We tested the hypotheses that impaired binding of VLDL and impaired VLDL-high density lipoprotein (HDL) interactions contribute to hyperlipidemia in NS. METHODS: TG and apoB secretion was measured using Triton WR 1339. Clearance of CMs by perfused hearts from NS and NAR was determined. Binding of VLDL from control, NS and NAR to rat aortic endothelial cells (RAECs) was measured prior to and following incubation with HDL from NS, NARs, and control. ApoE, protein, and TG content was determined. RESULTS: TG levels were greatest in NS (516 +/- 95 mg/dL), intermediate in NAR (193 +/- 20), and least in control (97 +/- 16, P = 0.05), while in contrast, TG secretion was least in NS (178 +/- 33 mg/dL/hour) versus 212 +/- 17 in NAR and 294 +/- 15 in control (P < 0.001 vs. NS). Clearance of CMs by NS and NAR hearts was the same and significantly reduced versus control (P < 0.005). Binding of NS-VLDL to endothelial cells was reduced, while NAR-VLDL binding was increased versus control (P < 0.001). Incubation of NS-VLDL with control or NAR HDL increased VLDL binding compared with binding following incubation with NS HDL (P < 0.001). CONCLUSION: Increased TG levels in both NS and NAR are the result of decreased TRL clearance. TG levels are greater in NS because of the presence of a combined defect: (1) a decrease in endothelial-bound LpL that occurs as a consequence of reduced serum albumin concentration, and (2) a defect in VLDL binding to endothelial-bound LpL. This latter defect occurs only in the presence of proteinuria and is conferred by HDL.

Animals↗

Familial intrahepatic cholestasis 1: studies of localization and function.

Mutations in the FIC1 gene constitute the molecular defect in familial intrahepatic cholestasis I (Fic1 [Byler's disease]) and benign recurrent intrahepatic cholestasis. This report describes the localization of Fic1 in rat liver and intestine, as well as biochemical and transfection studies that support its function as an energy-dependent aminophospholipid translocase. Immunocytochemistry of rat liver and immunoblotting of membrane fractions localized Fic1 to the canalicular, but not basolateral, plasma membrane domain. In the small intestine, Fic1 was localized to the apical membrane of epithelial cells. The distribution of Fic1 in liver plasma membrane fractions from control and taurocholate-treated rats correlated positively with adenosine triphosphate (ATP)-dependent aminophospholipid (phosphatidyl-serine) translocase activity. In canalicular membrane vesicles, translocase activity had an initial velocity of 3.3 nmol phosphatidylserine (PS) translocated per milligram of protein per minute and a K(m) (ATP) = 1.2 mmol/L; was inhibited by vanadate, N-ethylmaleimide, sodium azide, and calcium; and was unidirectional (i.e., from the outer to the inner canalicular plasma membrane leaflet). Transient transfection of CHOK1 cells with FIC1 cDNA resulted in appearance of FIC1 in membrane preparations and energy-dependent PS translocation in cells. These studies indicate that FIC1 is a canalicular P-type ATPase that participates in maintaining the distribution of aminophospholipids between the inner and outer leaflets of the plasma membrane. How this process produces cholestasis is under study.

Adenosine Triphosphatases↗

CheR- and CheB-dependent chemosensory adaptation system of Rhodobacter sphaeroides.

Rhodobacter sphaeroides has multiple homologues of most of the Escherichia coli chemotaxis genes, organized in three major operons and other, unlinked, loci. These include cheA(1) and cheR(1) (che Op(1)) and cheA(2), cheR(2), and cheB(1) (che Op(2)). In-frame deletions of these cheR and cheB homologues were constructed and the chemosensory behaviour of the resultant mutants examined on swarm plates and in tethered cell assays. Under the conditions tested, CheR(2) and CheB(1) were essential for normal chemotaxis, whereas CheR(1) was not. cheR(2) and cheB(1), but not cheR(1), were also able to complement the equivalent E. coli mutants. However, none of the proteins were required for the correct polar localization of the chemoreceptor McpG in R. sphaeroides. In E. coli, CheR binds to the NWETF motif on the high-abundance receptors, allowing methylation of both high- and low-abundance receptors. This motif is not contained on any R. sphaeroides chemoreceptors thus far identified, although 2 of the 13 putative chemoreceptors, McpA and TlpT, do have similar sequences. This suggests that CheR(2) either interacts with the NWETF motif of E. coli methyl-accepting chemotaxis proteins (MCPs), even though its native motif may be slightly different, or with another conserved region of the MCPs. Methanol release measurements show that R. sphaeroides has an adaptation system that is different from that of Bacillus subtilis and E. coli, with methanol release measurable on the addition of attractant but not on its removal. Intriguingly, CheA(2), but not CheA(1), is able to phosphorylate CheB(1), suggesting that signaling through CheA(1) cannot initiate feedback receptor adaptation via CheB(1)-P.

Adaptation, Biological↗

Pharmacokinetics and tolerability of the orally active selective epidermal growth factor receptor tyrosine kinase inhibitor ZD1839 in healthy volunteers.

OBJECTIVE: To investigate the pharmacokinetics and tolerability of ZD1839 (Iressa), an orally active selective epidermal growth factor receptor-tyrosine kinase inhibitor, in healthy volunteers. DESIGN: Two randomised, double-blind, placebo-controlled, parallel-group studies of pharmacokinetics and tolerability, followed by a nonblind, randomised, 2-period crossover study to assess the effect of food on bioavailability. SETTING: Two centres in the UK. STUDY PARTICIPANTS: Healthy male volunteers aged between 18 and 62 years. INTERVENTIONS: The first study investigated the pharmacokinetics and tolerability of ascending single oral doses of ZD1839 (1 to 75mg). The second study investigated the pharmacokinetics and tolerability of multiple doses of ZD1839 (100mg once daily for 3 days). The third study investigated the effect of food on the bioavailability of a single 50mg dose of ZD1839. OUTCOME MEASURES AND RESULTS: Peak plasma drug concentrations (Cmax) of ZD 1839 occurred between 3 and 7 hours after administration. Cmax and area under the concentration-time curve (AUC) were dose-proportional from 10 to 100mg. The terminal elimination half-life (t1/2beta) was 28 hours (range 12 to 51 hours). Cmax was reduced by 34% and AUC by 14% by ingestion of food; t1/2beta was not affected. Urinary recovery of ZD1839 was <0.5%, indicating that this was not a major route of elimination. The pharmacokinetics of ZD1839 during administration of multiple doses could be predicted from day 1 values. There were no serious adverse events or withdrawals, and the frequency of adverse events was similar that with placebo. CONCLUSIONS: These data support the further clinical investigation of ZD 1839. The elimination half-life suggests that once daily oral administration is appropriate.

Adolescent↗