Search PubMed⌕ Search

Biomedical subjects

J Perkins

Publications and source records attributed to J Perkins.

At least 37 records · Page 2Linked to original sources
PubMed2001

RNA expression analysis using an antisense Bacillus subtilis genome array.

We have developed an antisense oligonucleotide microarray for the study of gene expression and regulation in Bacillus subtilis by using Affymetrix technology. Quality control tests of the B. subtilis GeneChip were performed to ascertain the quality of the array. These tests included optimization of the labeling and hybridization conditions, determination of the linear dynamic range of gene expression levels, and assessment of differential gene expression patterns of known vitamin biosynthetic genes. In minimal medium, we detected transcripts for approximately 70% of the known open reading frames (ORFs). In addition, we were able to monitor the transcript level of known biosynthetic genes regulated by riboflavin, biotin, or thiamine. Moreover, novel transcripts were also detected within intergenic regions and on the opposite coding strand of known ORFs. Several of these novel transcripts were subsequently correlated to new coding regions.

Amino Acid Sequence↗
PubMed2001

Extraintestinal Crohn's disease: case report and review of the literature.

Crohn's disease is a granulomatous inflammatory bowel disease. Its pathologic findings include noncontiguous chronic inflammation and noncaseating granulomas. Any segment of the gastrointestinal tract can be involved, but it is uncommon to find that Crohn's disease has spread beyond the intestine. We describe the case of a man with extraintestinal Crohn's disease that was marked by quiescent involvement of the lower gastrointestinal tract and florid involvement of the nasal cavity, supraglottic structures, glottis, and skin.

Crohn Disease↗
PubMed2000

Self-assembly of an amphiphilic

The template-directed synthesis of a [2]rotaxane, in which a pi-electron deficient ring component-cyclobis(paraquat-p-phenylene)-is assembled around a pi-electron rich asymmetric monopyrrolotetrathiafulvalene unit on the rod section of an amphiphilic dumbbell component that is terminated by a hydrophilic dendritic stopper at one end and a hydrophobic tetraarylmethane stopper at the other end, is reported.

Journal Article↗
PubMed2000

The effects of mitomycin-C and stenting on airway wound healing after laryngotracheal reconstruction in a pig model.

OBJECTIVE: To assess the effects of mitomycin-C (MTC) and endoscopic stenting on airway wound healing after laryngotracheal reconstruction. DESIGN: A prospective, blinded, randomized controlled animal study. SUBJECTS: Twenty-six domestic pigs (Sus scrofula) divided into four groups. INTERVENTIONS: Each animal underwent single-stage laryngotracheal reconstruction (SSLTR) with auricular cartilage grafts and stenting. Group 1 animals were sacrificed on postoperative day 3, and group 2 animals on postoperative day 7. On postoperative day 7, groups 3 and 4 underwent endoscopy, stent removal, and application of MTC (0.5 mg/ml) or placebo (normal saline). Group 3 animals were sacrificed on postoperative day 14, group 4 animals on day 21. Two additional animals from each experimental group were prepared for election microscopy studies. Segments of reconstructed airway were evaluated grossly and histologically for all animals. Additional tonometric evaluation was performed on two stents to determine their compressive strength. MAIN OUTCOME MEASURES: Healing, reepithelization, graft incorporation, and airway diameter. RESULTS: Two-thirds of the animals demonstrated some degree of stent collapse on endoscopy. Granulation tissue formation was seen in all animals, and resolved with stent removal. No animal experienced airway compromise due to granulation tissue formation. Stenting was seen to induce a submucosal fibroproliferative response and scarring, with loss of normal glandular architecture, in all animals. MTC did not affect the acute inflammatory response, reepithelization of the graft site, or formation of the subepithelial fibroproliferative response. MTC treated animals, however, demonstrated better graft incorporation with fibrocartilage proliferation of the graft. Untreated animals demonstrated liquefactive necrosis of the graft, without evidence of neochondrification of the graft. CONCLUSIONS: The pig airway is an adequate model of wound healing following SSLTR and stenting. Metallic ballon expandable stents can be successfully used following SSLTR, allowing for immediate postoperative extubation. However, the formation of a submucosal fibroproliferative response and mucosal scarring seen in our study raises some concerns with the current stent design. Before stenting is widely clinically applied, the optimum stent design needs to be developed. Finally, MTC seems to prevent the liquefactive necrosis of SSLTR grafts and promote neochondrification, allowing improved graft incorporation. Further studies are needed to asses the long-term effects of MTC on healing and restenosis, and its effects on cartilage growth and formation, following SSLTR.

Animals↗
PubMed2000

Percutaneous penetration studies for risk assessment.

During the last few years the general interest in the percutaneous absorption of chemicals has increased. It is generally accepted that there is very few reliable quantitative and qualitative data on dermal exposure to chemicals in the general population and in occupationally exposed workers. In order to predict the systemic risk of dermally absorbed chemicals and to enable agencies to set safety standards, data is needed on the rates of percutaneous penetration of important chemicals. Standardization of in vitro tests and comparison of their results with the in vivo data could produce internationally accepted penetration rates and/or absorption percentages very useful for regulatory toxicology. The work of the Percutaneous Penetration Subgroup of EC Dermal Exposure Network has been focussed on the standardization and validation of in vitro experiments, necessary to obtain internationally accepted penetration rates for regulatory purposes. The members of the Subgroup analyzed the guidelines on percutaneous penetration in vitro studies presented by various organizations and suggested a standardization of in vitro models for percutaneous penetration taking into account their individual experiences, literature data and guidelines already in existence. During the meetings of Percutaneous Penetration Subgroup they presented a number of short papers of up to date information on the key issues. The objective was to focus the existing knowledge and the gaps in the knowledge in the field of percutaneous penetration. This paper is an outcome of the meetings of the Percutaneous Penetration Subgroup and reports the presentations on the key issues identified throughout the 3-year duration of the Dermal Exposure Network (1997-1999).

Journal Article↗
PubMed2000

Angiogenesis and intrauterine growth restriction.

Human placental development involves co-ordinated angiogenesis and trophoblast outgrowth that are compromised in intrauterine growth restriction. Adaptive angiogenesis in IUGR placental villi is a result of an imbalance in the orderly progression of the expression profile of vascular endothelial growth factor, placenta growth factor and angiopoietin during placental development. VEGF receptors and the angiopoietin receptor Tie-2 are expressed on trophoblast, and their activation leads to trophoblast proliferation, migration and production of nitric oxide. Thus, these vascular factors act as autocrine regulators of trophoblast behaviour in the development of the utero-/feto-placental circulation, an action independent of their well-established roles in vascular endothelium.

Animals↗
PubMed2000

Metabolism of fluroxypyr, fluroxypyr methyl ester, and the herbicide fluroxypyr methylheptyl ester. I: during percutaneous absorption through fresh rat and human skin in vitro.

Percutaneous absorption of pesticides is a major determinant for risk assessment. Furthermore, cutaneous metabolism plays a role in penetration of certain chemicals. Therefore, the aim of these studies was to determine the transdermal metabolism of three related compounds [the herbicide, fluroxypyr methylheptyl ester (FPMH), fluroxypyr methyl ester (FPM), and fluroxypyr (FP)] during penetration through human and rat skin in vitro. The data presented in this article show that both FPM and FPMH were completely metabolized during their passage through human and rat skin in vitro. The only metabolite produced was that of the hydrolysis product, FP, with no parent ester penetrating through the skin. The extent of FP formation within the skin was directly correlated to the degree of stratum corneum reservoir formation. The larger the stratum corneum reservoir, the lower the levels of FP recovered from within the skin. This suggests that as the ester partitioned out of the SC it was immediately hydrolyzed to FP, which could then pass freely through the remainder of the epidermis and dermis. Similar metabolic profiles were observed for the transdermal metabolism of FPM and FPMH in previously frozen rat skin, indicating the robust nature of the esterase enzymes involved. In conclusion, systemic exposure after skin contact with FPM or FPMH is likely to be to the acid metabolite, FP, only and not to the parent ester. In addition, the rate and extent of percutaneous absorption will be a major determinant of cutaneous metabolism.

Animals↗
PubMed2000

Metabolism of fluroxypyr, fluroxypyr methyl ester, and the herbicide fluroxypyr methylheptyl ester. II: in rat skin homogenates.

Fluroxypyr methyl ester (FPM) and the herbicide fluroxypyr methylheptyl ester (FPMH) are completely hydrolyzed during penetration through human and rat skin in vitro to the acid metabolite, fluroxypyr (FP) (). This article presents additional studies to determine the enzyme kinetics (K(m) and V(max)) of this ester hydrolysis, using crude rat whole-skin homogenate. Both FPM and FPMH were extensively metabolized in rat skin homogenates to the acid metabolite, FP. In no instance were any other metabolites detected. FPM was essentially hydrolyzed completely within 1 h. In FPMH incubations, there was still parent ester present after 24 h at all concentrations tested. The kinetics of hydrolysis of the two esters were different: V(max) was approximately 3-fold greater for FPM than FPMH (1400 and 490 micromol FP/min/g of tissue, respectively); however, K(m) values were very similar, 251 and 256 microM, respectively. Preliminary inhibitory studies suggest that FPM and FPMH are hydrolyzed by a carboxylesterase, because this reaction was inhibited by bis-p-nitrophenyl phosphate. Mercuric chloride (an inhibitor of A-esterase and arylesterase) and eserine (a cholinesterase inhibitor) had no inhibitory effect on the hydrolysis of FPM or FPMH. Taken together with the data presented by, it can be concluded that no parent ester will pass through the skin in vivo, only the metabolite, FP. Therefore, first pass metabolism will be complete before these compounds reach the systemic circulation.

Animals↗
PubMed1999

Measuring the indirect and direct costs of acute otitis media.

OBJECTIVES: To test a method of measuring the related cost of acute otitis media (AOM) and to provide a preliminary calculation of the indirect and directs costs associated with a single, medically treated episode of AOM. DESIGN: The Otitis Media Diary was used to measure indirect and direct costs associated with AOM in a prospective cohort study. Measured values included the parental time spent in otitis-specific child care and the number and type of medications used. A previously developed economic model was used to calculate the monetary costs associated with the value of caregiver time and the total opportunity cost of AOM. SETTING: The pediatric clinic of Madigan Army Medical Center, Tacoma, Wash. PATIENTS: A cohort of 25 children (12 with AOM and 13 controls) aged 1 to 3 years. MAIN OUTCOME MEASURES: Caregiver time and medication use. RESULTS: The total cost attributable to AOM in the 3-month period following diagnosis was $1330.58 (95% confidence interval, $1008.75-$1652.43), with the majority of that cost stemming from the indirect, rather than direct, costs of illness. After conservative estimates of unmeasured expenses, such as clinic visits and transportation, were accounted for, indirect costs, accrued primarily by parental time, accounted for nearly 90% (95% confidence interval, 87.1%-92.3%) of the total 3-month cost associated with AOM and its medical treatment. The cost items of the Otitis Media Diary were also highly correlated with each other and with other measures of clinical and functional health status. CONCLUSIONS: Otitis Media Diary measures of parental time and medication use appear to provide a more accurate means of calculating the real social costs attributable to the AOM disease process in this cost-effectiveness analysis.

Acute Disease↗
PubMed1999

Vascular surgical society of great britain and ireland: randomized controlled trial of heparin plus graduated compression stocking for the prophylaxis of deep venous thrombosis in general surgical patients

BACKGROUND: A randomized controlled study was undertaken to compare heparin with heparin plus graduated compression stockings (Brevet Tx, Seton Healthcare) in the prophylaxis of deep vein thrombosis (DVT) following abdominal surgery. METHODS: Sixty high-risk patients were recruited if they met at least two of the following criteria identified as predisposing to DVT: age greater than 39 years, malignancy, varicose veins, cardiac disease or hypertension, diabetes mellitus, obesity or previous thromboembolic episode. All patients received subcutaneous heparin and were randomized to receive Brevet Tx to either the right or left leg before surgery. The stocking was worn for 2 weeks after surgery. The patients underwent duplex imaging before surgery, and at 3, 6 and 14 days after operation. All scans were performed by one sonographer. The policy was to perform a venogram where a positive result was indicated by duplex scanning. RESULTS: Fifty-six patients completed the study. Six patients (11 per cent) suffered a DVT in the non-stockinged leg, but none in the stockinged leg (P = 0.016, McNemar's test). The DVTs occurred on days 3, 6, 7, 8, 9 and 12 following surgery. CONCLUSION: Brevet Tx in addition to low-dose subcutaneous heparin significantly reduced the incidence of DVT in high-risk patients undergoing abdominal surgery.

Journal Article↗
PubMed1999

Exercise and nursing therapy for patients with intermittent claudication.

Intermittent claudication is a common manifestation of arterial disease in the second half of life. Invasive treatments may be inappropriate or unsuccessful, leaving patients with a significant handicap. Nursing intervention can improve the functional ability and the general well-being of many patients. This paper provides an account of the development of an out-patient nursing service for patients with intermittent claudication. It focuses on the exercise training and the psychological support given to patients. A review of the first 102 claudicants referred to the programme shows the outcome for the patients in terms of improved walking ability. The details of the nursing intervention reported in the paper should help the growing number of nurses starting similar programmes for vascular patients. They may also be of interest to nurses caring for patients with other chronic health problems.

Adult↗
PubMed1999

Self-reported cervical screening practices and beliefs of women from urban, rural and remote regions.

This survey aimed to explore women's perceptions of a number of issues relating to the availability and utilisation of cervical cancer screening services in the rural, remote and urban regions of New South Wales (NSW) Australia. The survey involved urban, rural and remote regions of NSW determined by the definition of the Department of Community Services and Health. This was a cross-sectional telephone survey. Of the 339 eligible urban households, 265 (78%) completed interviews; of the 286 eligible rural households, 238 (83%) completed interviews; of the 285 eligible remote households, 230 (81%) completed interviews. Telephone contact was made with randomly selected households in each region. Women in the households were asked to complete a computer-assisted telephone interview. The survey addressed a number of issues relating to cervical screening: cervical cancer risk status; provider of Pap smear service; distance travelled to have a Pap smear; perceived barriers and facilitators to cervical screening. There was no statistically significant difference in the proportions of women from urban (74%), rural (76%), and remote (71%) regions who reported having a Pap smear in the 2 years preceding the survey. General practitioners provided the majority (more than 70%) of tests irrespective of region. Compared with women from urban areas, women from rural and remote areas were almost twice as likely to have had their last Pap smear from a male general practitioner. A greater proportion of women from remote regions had to travel for 60 minutes or more to access providers of Pap smear services. Few differences in the top three reported barriers to, and facilitators for screening were evident between regions and between those women who had and had not been adequately screened. Issues of distance, isolation and access to alternative service providers are a concern to women in rural and remote regions and should be considered by those involved in the implementation of cervical cancer screening services.

Journal Article↗
PubMed1998

Endoscopic management of biliary strictures in liver transplant recipients: effect on patient and graft survival.

BACKGROUND: Biliary strictures in liver transplant recipients cause significant morbidity and can lead to reduced patient and graft survival. METHODS: Of 251 liver transplant recipients, 22 patients with biliary strictures were categorized into two groups: donor hepatic duct (n = 12) or anastomotic (n = 10). Strictures were dilated and stented. Endoscopic therapy was considered successful if a patient did not require repeat stenting or dilation for 1 year. RESULTS: Patient and graft survival did not differ significantly in the 22 patients compared with patients without strictures (relative risk of death and graft survival 1.8 and 1.3). Donor hepatic duct strictures required significantly longer therapy than anastomotic strictures (median days 185 versus 67, p = 0.02). Twenty-two months after the first endoscopic treatment, 73% of the donor hepatic duct stricture group were stent free compared with 90% of the anastomotic group (p = 0.02). The former group had significantly more (p < 0.05) hepatic artery thrombosis (58.3% versus 10%), cholangitis (58.3% versus 30%), choledocholithiasis (91% versus 10%), and endoscopic interventions. No patient undergoing endoscopic treatment required retransplantation or biliary reconstruction during a median follow-up of 35.7 months. CONCLUSION: Endoscopic therapy of biliary strictures after liver transplantation is effective and is not accompanied by reduced patient or graft survival.

Adult↗
PubMed1998

Vaginal weights for assessment and training of the pelvic floor.

Urinary incontinence is a common problem for women. A trial of conservative treatment is frequently suggested before considering other treatment options. One method involves the use of vaginal weights for retraining the pelvic floor muscle. This review examines articles and abstracts on vaginal weights published in English or with abstracts in English between 1985 and 1997. It concludes that, despite some practical and theoretic concerns, there is adequate clinical evidence to support the use of weights in selected populations. Weights may be an effective training aid for women with mild to moderate stress incontinence, particularly in the absence of severe pelvic organ prolapse. They also may be useful for pelvic floor strengthening during the immediate postpartum period, as a behavioral program for continence maintenance, and for self-management programs. Suggestions for further research to refine treatment parameters and client selection are also presented.

Exercise Therapy↗
PubMed1998

Women's experiences of having a colposcopic examination: self-reported satisfaction with care, perceived needs and consequences.

This study was conducted in seven gynaecological clinics in New South Wales (NSW), Australia. The study aimed to assess the level of satisfaction with care, unmet needs and consequences following the procedure reported by women having a colposcopic examination. Of the 161 eligible women attending colposcopy clinics who were approached to take part, 156 (97%) gave written consent to participate and 138 (86%) completed interviews. Consenting women were telephoned within 1 week of their clinic visit to complete a computer-assisted telephone interview (CATI). The survey addressed a number of issues relating to the care they received during their colposcopic examination: satisfaction with care, satisfaction with the waiting time to have a colposcopy, preferences for provider gender, information and health care needs while waiting for the colposcopy, information and health care needs during the colposcopy, short-term physical consequences and shortterm psychosocial consequences of the procedure. Results indicate that satisfaction with care among women ranged from 69% to 96%. The highest expressed needs while waiting for the colposcopy were for information about risks of cancer (91%), reasons for needing a colposcopy (86%), and the colposcopy procedure (86%). Women reported that outcomes such as anxiety and disinterest in sex had further worsened or not been improved following the colposcopy. The results indicate that interventions to address specific concerns would need to be designed, implemented and evaluated.

Journal Article↗
PubMed1998

Otitis media health status evaluation: a pilot study for the investigation of cost-effective outcomes of recurrent acute otitis media treatment.

There are no reliable and valid instruments that measure otitis media clinical or functional health status in children ages 1 to 3 years. This study develops and tests three new instruments of clinical and functional otitis health status: the Otitis Media Clinical Severity Index (OM-CSI), the Otitis Media Functional Status Questionnaire (OM-FSQ), and the Otitis Media Diary (OMD). The OM-CSI was found to be a reliable measure of clinical acute otitis media (AOM) severity, with high internal consistency (Cronbach's alpha) scores, as well as an accurate indicator of AOM severity. The OM-FSQ and OMD were demonstrated to be reliable and valid measures of otitis-specific functional health status, with reproducible scores over time, high internal consistency alpha scores, and high correlation with measures of AOM clinical severity and other functional health status instruments. These three new instruments were also sensitive and specific indicators of AOM episodes.

Acute Disease↗