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Biomedical subjects

J Porter

Publications and source records attributed to J Porter.

At least 55 records · Page 3Linked to original sources
PubMed1999

Learning to count: a difficult task?

This article is concerned with the acquisition of counting skills in pupils with Down syndrome. Data from a larger survey of pupils with severe learning difficulties is explored to investigate the types of errors children make at the earliest stages of learning to count. The pattern of responding was consistent with the view that children with Down syndrome have particular difficulties in tasks utilising auditory sequential memory, in this case learning the number string. The practical implications of these findings are discussed.

Adolescent↗
PubMed1999

The street/treatment barrier: treatment experiences of Puerto Rican injection drug users.

This study describes, through ethnographic interviews, the treatment experiences of Puerto Rican long-term heroin users who are at extremely high risk for HIV infection and the barriers they perceive to drug treatment. On the basis of this information we suggest policy recommendations for increasing drug treatment access for Puerto Rican long-term injectors of heroin. It is critical that Puerto Rican populations access drug treatment facilities given their risk factors for HIV infection and the high rate of poverty in Puerto Rican communities that exacerbates drug use.

Adult↗
PubMed1999

Is cough alone adequate to screen HIV-positive persons for tuberculosis preventive therapy in developing countries?

Although the efficacy of isoniazid in the prevention of tuberculosis in HIV-infected persons with a positive tuberculin skin test is proven, several feasibility issues remain unanswered. In resource poor settings where a chest radiograph may not be readily available, the question of whether cough alone is an adequate screening tool needs to be considered. We analysed screening data collected as part of an isoniazid efficacy study. Although the study was not designed specifically to answer this question, the data suggests that cough alone may be inadequate for screening patients for potential tuberculosis preventive therapy, and that a chest radiograph may be necessary. Feasibility studies are needed.

AIDS-Related Opportunistic Infections↗
PubMed1999

Inhibition of neutrophil apoptosis after elective surgery.

BACKGROUND: Neutrophils play a crucial role in host defense against infections, but their inappropriate infiltration and activation within tissues can cause host tissue damage through release of reactive oxygen metabolites, metalloproteinases, and proinflammatory cytokines. The termination of a neutrophil-mediated inflammatory response is effected through programmed cell death or apoptosis. Delayed neutrophil apoptosis is associated with proinflammatory diseases, such as the systemic inflammatory response syndrome. Surgery induces a profound inflammatory response; therefore, neutrophil apoptosis of patients undergoing elective surgery was investigated. METHODS: Nonseptic patients undergoing elective orthopedic surgery while under epidural anesthesia had neutrophils and platelet-poor isolated from whole venous blood harvested at 4 time points: pre-epidural, 45 minutes postepidural but before surgical intervention, 1 hour postsurgical incision, and 24 hours postsurgery. Neutrophil apoptosis was quantified at 1, 12, and 24 hours in culture by immunofluorescence flow cytometry of annexin V and propidium iodide staining and confirmed by TUNEL (terminal deoxynucleotidyl transferase nick end labeling) assay for DNA strand breaks. Serum cytokines were quantified by specific enzyme-linked immunosorbent assay. RESULTS: Spontaneous neutrophil apoptosis after elective surgery was significantly (P < .001) inhibited with an effect evident within an hour of surgical incision and persisting at 24 hours postsurgery. The addition of patients' 24 hour postoperative plasma to healthy neutrophils markedly (P < .01) reduced neutrophil apoptosis, whereas plasma taken an hour after surgical incision was ineffective. Interleukin (IL)-6 was notably increased (1395 +/- 196 pg/mL, P < .01) 24 hours postsurgery and at this postoperative concentration inhibited (P < .01) apoptosis of normal neutrophils. Levels of other inflammatory mediators (IL-1 beta, tumor necrosis factor alpha, granulocyte-macrophage colony-stimulating factor, soluble Fas, soluble Fas ligand) were unaltered. The anti-inflammatory cytokine IL-10 was only slightly increased 24 hours postsurgery (8.32 +/- 2.99 pg/mL); however, the addition of recombinant human IL-10 (10 ng/mL) counteracted (P < .05) inhibition of neutrophil apoptosis induced by IL-6 and post-surgery plasma. CONCLUSIONS: These results identify marked inhibition of neutrophil apoptosis after elective surgery and suggest that the inhibition of neutrophil apoptosis in the postoperative period is, at least in part, a result of soluble circulating factors. The marked imbalance favoring proinflammatory over anti-inflammatory cytokine release in the immediate postoperative period mediates the overwhelmingly antiapoptotic net capacity of postsurgery plasma.

Aged↗
PubMed1999

Shifting the paradigm in tuberculosis control: illustrations from India.

Drawing on literature from India and key contributions from social science, this paper asks and attempts to answer the question 'who is to blame for treatment failures in TB'? Some key lessons emerge: effective tuberculosis control cannot be achieved so long as the disease is considered in isolation from the social processes that maintain it, create the conditions facilitating its spread and act as barriers to care. Insights into the economic and social burdens incurred with a diagnosis of TB are essential to understand why many patients, especially the most disadvantaged, are unable to comply with treatment regimens. TB and health care interventions need to be appropriate to the health service contexts in which they are applied, and sensitive to the competing demands, needs and priorities of people's lives. The paper argues for the need to reorient TB control programmes towards enabling patients to obtain care. The problem of access emerges as central to people's ability to obtain and maintain appropriate therapy. Examples and characteristics of successful non-governmental projects, from which policy makers, programmers and practitioners could learn, are outlined and contrasted with more rigid directly observed treatment approaches. We conclude that treatment failures are not patient failures, and that TB control programmes need to address the social dimensions of TB, and adhere to the principles of good TB care, with the same commitment that is devoted to ensuring patients follow treatment guidelines. We suggest a paradigm shift away from a focus on diseased patients towards enabling health in the community.

Antitubercular Agents↗
PubMed1999

The effects of fee bundling on dental utilization.

OBJECTIVE: To examine dental utilization following an adjustment to the provincial fee schedule in which preventive maintenance (recall) services were bundled at lower fees. DATA SOURCES/STUDY SETTING: Blue Cross dental insurance claims for claimants associated with four major Ontario employers using a common insurance plan over the period 1987-1990. STUDY DESIGN: This before-and-after design analyzes the dental claims experience over a four-year period for 4,455 individuals 18 years of age and older one year prior to the bundling of services, one year concurrent with the change, and two years after the introduction of bundling. The dependent variable is the annual adjusted payment per user. DATA COLLECTION/EXTRACTION METHODS: The analysis was based on all claims submitted by adult users for services received at recall visits and who reported at least one visit of this type between 1987 and 1990. In these data, 26,177 services were provided by 1,214 dentists and represent 41 percent of all adult service claims submitted over the four years of observation. PRINCIPAL FINDINGS: Real per capita payment for adult recall services decreased by 0.3 percent in the year bundling was implemented (1988), but by the end of the study period such payments had increased 4.8 percent relative to pre-bundling levels. Multiple regression analysis assessed the role of patient and provider variables in the upward trend of per capita payments. The following variables were significant in explaining 37 percent of the variation in utilization over the period of observation: subscriber employment location; ever having received periodontal scaling or ever having received restorative services; regular user; dentist's school of graduation; and interactions involving year, service type, and regular user status. CONCLUSIONS: The volume and intensity of services received by adult patients increased when fee constraints were imposed on dentists. Future efforts to contain dental expenditures through fee schedule design will need to take this into consideration. Issues for future dental services research include provider billing practices, utilization among frequent attenders, and outcomes evaluation particularly with regard to periodontal care and replacement of restorations.

Adolescent↗
PubMed1998

A study of immunological responses of sheep clinically-affected with paratuberculosis (Johne's disease). The relationship of blood, mesenteric lymph node and intestinal lymphocyte responses to gross and microscopic pathology.

Nineteen adult sheep diagnosed as having clinical paratuberculosis (Johne's disease) and 16 unaffected controls were examined in this study. Animals were tested for the presence of circulating antibodies of Mycobacterium avium ssp. paratuberculosis (M. a. paratuberculosis) and lymphocytes derived from the blood, mesenteric lymph nodes and intestines were examined for cell-mediated immune (CMI) responses to Johnin pure protein derivative (Johnin-PPD: J-PPD). Bacteriological examinations were carried out on faeces and tissues and any mycobacterial isolates identified as M. a. paratuberculosis (IS900+) or M. avium ssp. silvaticum (M. a. silvaticum) (IS901+) by polymerase chain reaction (PCR). Full necropsy and histopathological studies were performed and diseased animals were categorised on the basis of having a lepromatous or tuberculoid form of intestinal pathology. Unaffected control sheep were generally antibody-negative and demonstrated varying CMI responses to J-PPD. Clinically-affected animals were almost always antibody-positive with variable CMI responses. A correlation was observed between the histological lesion type in the intestine and the cellular immune response. Tuberculoid-type lesions were associated with strong CMI responses in lymphocytes derived from the peripheral blood, mesenteric lymph node and intestine, whereas lepromatous-type lesions were associated with weak CMI responses in all tissues examined.

Animals↗
PubMed1998

The substantial impact of von Willebrand disease on menstruation.

von Willebrand disease (vWd) is the most common of all congenital bleeding disorders with an estimated prevalence of 1-3% in the general population. However, the gynecological complications have not been thoroughly described.Objective: To compare the clinical and quality of life aspects of vWd in menstruating women in relation to a cohort of menstruating women in the general population.Methods: A patient questionnaire and provider survey of the medical and quality of life aspects of menstruation was administered to 81 menstruating vWd patients registered at four geographically linked Hemophilia Treatment Centers. The questionnaire was also administered to 150 menstruating women volunteers that comprised a control group used to determine normal coagulation levels in menstruating women. We assessed the impact on quality of life of menses in both of the cohorts by a Likert scale of 1-10 with 10 being "most significant impact" using 7 quality of life parameters with those comparisons by Wilcoxon rank sum test.Results: 88% of the vWd patients (pts) had type I vWd, the remaining Type II or unknown. The mean age of the vWd patients was 31.6 +/- 10.3; the mean age of the control group was 35.5 +/- 7.6. The following comparisons were made using chi(2) and Wilcoxon rank sum test:Conclusions: vWd markedly diminishes the quality of life during menses. This observation warrants efforts to reduce the attendant morbidities of vWd in menstruating women.

Journal Article↗
PubMed1998

Penetrating ureteric injuries.

Injury to the ureter is relatively rare. We retrospectively reviewed our experience with 21 cases of ureteric injury from penetrating trauma at the Lincoln Medical Center. Two injuries resulted from stab wounds and 19 from gunshot wounds. Total ureteric disruption occurred in 14 cases, partial transection in four and contusion in three. Preoperative screening was unreliable in accurately predicting the injury with hematuria being present in 66 per cent of cases. Similarly, intravenous urogram was diagnostic in 14 per cent and suspicious in another 42 per cent. Most injuries were diagnosed intraoperatively and exploration of the retro peritoneum remains the only definitive method of excluding ureteric injuries. Most patients were critically ill (mean ISS 27) due to associated injuries (90 per cent). Neither peritoneal contamination associated with hollow viscous injuries nor hypotension adversely affected the healing of ureteric anastomoses. Anastomotic leak developed in three (14 per cent) cases and one of them required operative correction. Another two patients developed infections related to the urinary tract.

Abdominal Injuries↗
PubMed1998

Investigation and diagnosis of diarrhea caused by sodium phosphate.

Because there are no published reference values for fecal phosphate concentration or output, diagnosing surreptitious use of phosphate laxatives has been difficult. The purposes of this study were to determine normal fecal phosphate levels and to quantitate and chemically analyze diarrhea produced by sodium phosphate. Timed stool collections were obtained from 20 normal subjects during 25 study periods (normal controls), from 27 normal subjects with diarrhea induced by a variety of laxatives not containing phosphate during 234 study periods (diarrhea controls), and from 10 normal subjects during 14 periods after ingestion of 45 or 22.5 ml of a commercially available 66% sodium phosphate solution (Fleet Phospho-Soda). All stools were analyzed for soluble phosphate concentration, and daily output was calculated. The upper limits of normal for soluble fecal phosphate concentration and output, derived from the normal controls and diarrhea controls, respectively, were 33 mmol/liter and 15 mmol/day. Diarrhea produced by 45 ml of sodium phosphate was watery and voluminous, with fecal weights averaging 1078 g/day (range 601-1713 g/day). Measured fecal phosphate concentrations and outputs averaged 85 mmol/liter and 92 mmol/day, respectively, and all values were significantly elevated. Soft, less voluminous stools were produced with 22.5 ml of sodium phosphate but all had an abnormally high soluble phosphate concentration and 24-hr output. In conclusion, the upper limits of normal for soluble fecal phosphate concentration and output established in this study should be useful in the chemical diagnosis of phosphate-induced diarrhea.

Adult↗
PubMed1998

An evaluation of lectin-mediated magnetic bead cell sorting for the targeted separation of enteric bacteria.

Lectin-labelled magnetic beads were assessed and compared with antisera as an alternative approach for the targeted separation and isolation of enteric bacteria. Of the 16 lectins tested against a range of bacterial species, concanavalin A (conA) showed the greatest potential. Agglutination of bacterial cells in suspension using conA and methods for effective labelling of the magnetic beads with the lectin were optimized. ConA-labelled magnetic beads were compared with antibody-labelled beads for recovery of bacterial cells from pure or mixed laboratory cultures and from natural populations in river water. Recovered cell populations were free from environmental impurities and a high percentage of the culturable cells was extracted. Specific cell recovery was found to be variable, but the use of lectins offers some promise as an alternative cell discriminator.

Agglutination Tests↗
PubMed1998

Effect of epidural fentanyl on neonatal respiration.

BACKGROUND: The addition of opioids to epidural infusions for laboring mothers may reintroduce the problem of neonatal depression seen with systemic opioids. The authors studied neonatal respiration and neurobehavior in newborns of mothers randomized to receive epidural analgesia with or without fentanyl. METHODS: One hundred thirty-eight women in labor received loading doses of plain bupivacaine. When pain-free, they received an infusion of either 0.125% bupivacaine alone or 0.0625% bupivacaine with 2.5 microg/ml fentanyl. After delivery, transcutaneous oxygen tension and carbon dioxide tension were recorded in the newborns every 10 s until 90 min after delivery using a transcutaneous oxygen-carbon dioxide monitor. Umbilical venous and arterial acid-base status, Apgar scores, and Neurologic and Adaptive Capacity Scores 2 h and 24 h after delivery were measured. The umbilical venous plasma fentanyl concentration was correlated with indices of neonatal respiration and welfare in the fentanyl group. RESULTS: One hundred fourteen newborns delivered vaginally were studied. In the fentanyl group, the mean (range) maternal dose of fentanyl was 184 microg (range, 53-400), and the umbilical venous fentanyl concentration was 0.077 ng/ml (range, <0.021 to 0.244). There were no significant differences between the groups for any indices of neonatal respiration or neonatal welfare, and the plasma fentanyl concentration did not correlate with any of these indices. CONCLUSIONS: The results suggest that fentanyl added to epidural bupivacaine infusions during labor does not depress neonatal respiration or adversely affect neurobehavioral scores and other indices of neonatal welfare.

Adult↗
PubMed1998

The understanding of counting in children with severe learning difficulties and nursery children.

BACKGROUND: Little is known about the development of counting in children with severe learning difficulties (SLD) although early research has stressed the rote nature of children's understanding. AIMS: We investigated the attainments of children with SLD both with regard to their skills and understanding of counting and compared performance with typically developing preschoolers. SAMPLES: Twenty-five children with SLD (aged 7-14 years) matched to one group of preschoolers on the basis of their receptive language scores and to a second group using a broader measure, performance on a non-verbal intelligence test. METHODS: Children were presented with a simple counting task and an error detection task. RESULTS: There were no differences between the SLD and preschool groups in the mean scores on either task. In each group more children were able to count than detect errors. However, analysis of their counting performance suggested a difference in the acquisition of counting skills. Furthermore, the SLD group included three transitional children-able to count competently but not able to detect errors. This pattern was not evident in the preschool groups: if the children were competent counters they were able to detect errors. CONCLUSION: The acquisition of procedures for counting is an important first step in developing an understanding of counting. There is some evidence to suggest that children with SLD may have difficulty learning the number words and producing them whilst pointing to count items. We cannot assume that children with SLD will move smoothly towards an understanding of counting. These aspects warrant further investigation and raise the important question of what experiences best promote the acquisition of procedures and understanding in children with SLD.

Adolescent↗