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Biomedical subjects

J M Phillips

Publications and source records attributed to J M Phillips.

At least 55 records · Page 3Linked to original sources
PubMed1996

Tolerance and suppression in a primed immune system.

The induction of tolerance in a primed immune system would be valuable therapeutically, but has been difficult to achieve. Mice primed to multiple minor histoincompatible antigens (minors) are able to rapidly reject secondary grafts using either their CD4+ or CD8+ T-cell subpopulations. Short courses of treatment with nonlytic anti-CD4 and anti-CD8 antibodies targeted at both T-cell subsets can induce long-term peripheral T-cell tolerance in primed mice. We examine the mechanisms by which peripheral tolerance is maintained, and show that tolerant mice harbor CD4+ T cells capable of specifically suppressing rejection mediated by either subset of primed T cells. Remarkably, elimination of CD4+ T cells from tolerant mice resulted in graft rejection, suggesting that graft-reactive CD8+ T cells had not been eliminated, but had been under continuous regulation by "tolerant" CD4+ T cells. This result demonstrates that it may be possible to establish therapeutic operational tolerance without permanently inactivating all antigen-reactive cells.

Adoptive Transfer↗
PubMed1996

CD4 mAbs prevent progression of alloactivated CD4+ T cells into the S phase of the cell cycle without interfering with early activation signals.

Knowing that several CD4 mAbs may delay allograft rejection in the absence of circulating CD4+ lymphocyte depletion in vivo, we investigated the mechanisms whereby CD4 mAbs can interfere with the development of alloreactive T cells in the mixed lymphocyte reaction (MLR). In agreement with previous reports, CD4 mAbs of different species (mouse, rat, humanized), isotypes (IgG1, IgG2a, and IgG2b) and different epitope specificities decreased 3H-TdR incorporation in MLR, using monocyte-depleted or CD4+ T lymphocyte-enriched blood mononuclear cells as responders. Those effects were achieved at nonsaturating mAb concentration and were still demonstrable upon delayed addition of CD4 mAbs. However, CD4 mAbs decreased neither the number of blast cells nor the expression of CD25 (the alpha chain of IL-2 receptor), indicating that initial activation events leading to blast transformation were not affected. Determination of cytokine gene expression by non competitive quantitative RT-PCR and measurement of protein concentration in supernatants demonstrated that CD4 mAbs did not decrease IFN-gamma induced by alloactivation. However IL-2 concentration was decreased in all supernatants whereas IL-2 mRNA expression, only slightly decreased at 24 hr, and dropped after 72 hr. IL-5 and IL-10 mRNAs, equally expressed by stimulated or nonstimulated responder cells, were not affected by CD4 mAbs. IL-4 mRNA was not detectable. Furthermore, addition of rIL-2, rIFN-gamma or rIL-4 did not overcome proliferation inhibition. The data provide a novel insight into the mechanisms of CD4 mAbs immunosuppresssion that associates a decrease of IL-2 expression with an IL-2 resistant blockade of the progression of activated CD4+ T cells from the G1 to the S phases of the cell cycle.

Antibodies, Monoclonal↗
PubMed1996

Prevalence and prediction of positive discrepancy creation: examining a discrepancy between two self-regulation theories.

The conflicting perspectives of control theory (CT) and self-efficacy theory (SET) concerning positive discrepancy creation (PDC) were tested and are discussed. According to CT, discrepancies between past performance and future goals are continually reduced. This is contrary to SET's focus on setting future goals higher than past performance levels. Participants performed several trials in a multitask environment, during which they did as many or as few problems as they chose on each of 4 intellectual tasks. Results suggest that PDC is not uncommon in a multitask environment, even after extensive task experience. Regression decomposition techniques identified 2 types of PDC: goal driven and performance driven. Need for achievement, instrumentality, and expectancy predicted the 2 types of PDC with varying success across the 4 tasks. The 2 types of PDC reflect the different theoretical approaches and these 2 self-regulation theories.

Goals↗
PubMed1996

Outcome of surgical decompression of the second cervical root for cervicogenic headache.

OBJECTIVE: There is limited information on the surgical treatment of cervicogenic headache (CH). The objective of this study is to analyze the utility of microsurgical decompression of the second cervical (C2) root and ganglion as a treatment for CH. METHODS: Thirty-nine sequential C2 root and ganglion decompressions, performed for the treatment of CH on 35 patients at the Dartmouth-Hitchcock Medical Center during a 70-month period, were analyzed retrospectively. Preoperative factors and intraoperative findings were evaluated with respect to outcome. RESULTS: At a mean follow-up of 21 months, 12 patients (13 sides) were pain free, and 15 were adequately improved (18 sides). Treatment eventually failed in eight patients. No patient, however, was worse after surgical intervention. There was no major morbidity or mortality associated with the operation. The eight patients with unsatisfactory outcome were evaluated for a possible second operation, and four underwent it. One patient of the four is pain free after 28 months, and two gained adequate improvement at 3 and 12 months. The fourth patient required a third operation but has achieved adequate relief at 6 months. Thus, the overall success rate (either pain free or with adequate improvement) was 90%. No specific prognostic factors could be established, other than the accepted diagnostic criteria and successful anesthetic blockade of the C2 root and ganglion. CONCLUSION: The results suggest that microsurgical decompression of the C2 root and ganglion has some utility in treating CH. The accepted diagnostic criteria and success of anesthetic blockade of C2 should identify the subset of patients with CH predominantly caused by C2 root or ganglion effect at this level, which may favor surgical treatment.

Adult↗
PubMed1996

Performance traits, hoof mineral composition, and hoof characteristics of bulls in a 112-day postweaning feedlot performance test.

OBJECTIVE: To evaluate relations between hoof and performance data from bulls fed in a 112-day standardized postweaning feedlot performance test. ANIMALS AND DESIGN: Breeds included were Angus (n = 20), Brangus (n = 19), Hereford (n = 31), and Simmental (n = 53). Hoof measurements, scores, and a 0.5-g hoof tissue sample were obtained from the right forefoot of bulls on days 1 and 112 of 4 tests conducted in 3 locations in Arkansas. Data were analyzed, using least squares ANOVA. The model used included an overall mean, breed, farm of origin within breed, initial age, and initial weight within breed and residual. Residual and canonical correlations of the traits studied were calculated. RESULTS: Residual correlations were found between some hoof minerals. Canonical correlations between performance traits and hoof minerals, between hoof characteristics and hoof minerals, and between hoof characteristics and performance traits were 0.62 and 0.45 (P < 0.005), 0.54 and 0.40 (P < 0.05), and 0.56 (P < 0.01) and 0.26 (P > 0.05), respectively. CONCLUSIONS: These data suggest that a relation exists between performance traits and hoof mineral composition and hoof characteristics and mineral composition. The visual scoring system for these data did not genetically separate bulls on the basis of claw quality. CLINICAL IMPLICATIONS: By selecting bulls with high claw quality, cattle producers are decreasing the chances of premature culling because of hoof laminitis. Therefore, by obtaining hoof measurements and mineral composition in a feedlot performance test, producers should have the tools to select bulls for increased lifetime performance.

Analysis of Variance↗
PubMed1995

Operative hysteroscopy: American Association of Gynecologic Laparoscopists' 1993 membership survey.

The 1993 American Association of Gynecologic Laparoscopists' membership survey on operative hysteroscopy had 713 respondents reporting 14,707 procedures. Directed biopsy and endometrial ablation were the most commonly reported. The majority of operative hysteroscopies were performed for a complaint of abnormal bleeding (78%). The most frequent reported complication was uterine perforation not requiring transfusion (14.2/1000 procedures). The rates of water intoxication and pulmonary edema stayed essentially unchanged from 1991: 2/1000 in 1993 compared with 1.4/1000 in 1991. No deaths were reported this year. The consistency in rates of procedures performed and complications within the three surveys conducted in 1988, 1991, and 1993 add credibility to the data from these retrospective studies.

Biopsy↗
PubMed1995

Operative laparoscopy: American Association of Gynecologic Laparoscopists' 1993 membership survey.

The American Association of Gynecologic Laparoscopists' 1993 membership survey on operative laparoscopy had 825 respondents reporting 45,042 procedures. The most frequent indication was pelvic pain (56% of procedures), followed by infertility (38%). There were 7382 laparoscopically assisted hysterectomies reported. Compared with 1988 and 1991 survey data, the rates of unintended laparotomy, hemorrhage, and bowel or urinary tract injury increased, but the overall complication and death rates remained essentially unchanged.

Female↗
PubMed1995

Laparoscopic sterilization: American Association of Gynecologic Laparoscopists' 1993 membership survey.

The 1993 membership survey of the American Association of Gynecologic Laparoscopists received 938 responses, or 13% of the membership. The surgeons reported performing 22,966 sterilizations and 36,482 diagnostic procedures. The distribution of sterilization techniques has remained stable since 1985. Complication rates associated with diagnostic procedures remain consistently higher than those with sterilizations. One death was reported from sterilization, none for diagnostic procedures.

Female↗
PubMed1995

Antenatal diagnosis and management of fetomaternal alloimmune thrombocytopenia.

Fetomaternal alloimmune thrombocytopenia (FMAT) arises from maternal-fetal platelet antigen incompatibility, which stimulates the production of maternal immunoglobulin G (IgG) platelet-specific antibody. Transplacental passage of this antibody results in fetal platelet destruction and consequent thrombocytopenia. Sequelae of thrombocytopenia may be observed in both the fetus and neonate with intracranial hemorrhage occurring in approximately 10 to 30% of affected infants. No antenatal universal screening test is currently available to detect the 50% of cases occurring in the first pregnancy. The recurrence rate in subsequent pregnancies is 75 to 85%, with a tendency to increasing disease severity. Paternal platelet genotyping is recommended to assist in risk counseling following an affected pregnancy. Prenatal therapeutic strategies are aimed at elevating the fetal platelet count in affected pregnancies and thus decreasing hemorrhagic sequelae. The most effective treatment regimen is uncertain, but encouraging results are reported with the use of maternal intravenous gamma globulin. We report our experience in the antenatal diagnosis and management of FMAT.

Adult↗
PubMed1995

Adherence to breast cancer screening guidelines among African-American women of differing employment status.

The purpose of this study was to identify and compare the adherence to breast cancer screening guidelines [monthly breast self-examination (BSE), age-related mammography, yearly professional breast examination (PBE)] among African-American women (AAW) of differing employment status. The Breast Cancer Screening Model served as the organizing framework for this study. One hundred fifty-four subjects were quota sampled according to age and employment group status. Findings showed that 63% of all subjects practiced monthly BSE and 76% had undergone a yearly PBE. Only 20% of all subjects had undergone a mammogram according to the age-related guidelines. Overall, breast cancer screening rates were lower than recommended across all employment groups. Variables that uniquely explained 74% of the variance in monthly BSE included level of education, marital status, social influence, knowledge of BSE, and intention to do BSE in the future. Age group, previous instruction on mammography, income, and perceived barriers related to mammography explained 15% of the variance in age-related mammography. Finally, marital status, previous information on PBE, and intrinsic motivation explained 42% of the variance in yearly PBE. Together, these findings highlight the need for (a) the development of strategies that will promote long-term adherence to all three screening guidelines, and (b) the design of qualitative studies using a representative sample of AAW of differing socioeconomic backgrounds.

Adult↗
PubMed1994

Operative laparoscopy: American Association of Gynecologic Laparoscopists, 1993 membership survey.

The American Association of Gynecologic Laparoscopists' 1993 membership survey on operative laparoscopy had 1205 respondents reporting 80,031 procedures. Diagnostic laparoscopy remains the most common procedure, followed by adhesiolysis and laparoscopically assisted vaginal hysterectomy. This survey was particularly designed to chronicle the rate of complications as increasingly complex laparoscopic procedures are performed.

Data Collection↗
PubMed1994

Efficacy of Brahman breeding in the management of insecticide-resistant horn flies (Diptera: Muscidae) on beef cattle.

The efficacy of Brahman breeding used as an alternative tactic to manage insecticide-resistant populations of adult horn flies, Haematobia irritans irritans (L.), was determined. Concentration-mortality bioassays done at Booneville and Hope, AR, in 1988 and 1989, respectively, showed that horn fly populations were resistant to diazinon, pirimiphos methyl, tetrachlorvinphos, and methoxychlor. Data showed loss of field efficacy for coumaphos and delnav. Mean horn fly counts on Braham cows were significantly lower than on Angus cows for all sampling dates in 1989 and 1990. Mean fly counts on Brahman x Angus cows were approximately intermediate to the two purebred mean fly counts. Brahman breeding caused significant reductions in the number of organophosphate-resistant horn flies, which had been equal to or greater than that obtained from continued spraying with organophosphate insecticides. The Brahman x Hereford cows, which have one-eighth greater Brahman breeding than the Brangus cows, had fewer horn flies on 48 of 56 sampling dates in 1988-1990 and significantly fewer flies on 37 sampling dates. The effectiveness of Brahman breeding in causing lower numbers of insecticide-resistant horn flies significantly increased as the percentage of Brahman breeding increased.

Animals↗
PubMed1994

Critical appraisal of research literature by expert and inexperienced physical therapy researchers.

BACKGROUND AND PURPOSE: In this study, critical appraisal skills of physical therapists who were inexperienced and expert researchers were compared and the effect of the following independent variables on the appraisal skills of novices was examined: years of physical therapy practice, postgraduate experience with research, level of comfort with research, journal reading habits, and content-specific expertise. SUBJECTS AND METHODS: Four expert and 20 inexperienced researchers critiqued the same research article. A content analysis of the expert critiques was used to develop a set of 12 items of concerns about the study. RESULTS: Experts identified a mean of 7.75 items of concern; novices identified a mean of 3.95 items. For 10 of the 12 items, a greater proportion of experts identified each concern compared with the novices. Novices had comparatively less difficulty identifying concerns with internal validity than they did identifying issues relating to construct validity. Only one of the variables--content-specific expertise--was associated with differences in critical appraisal skills among the novices. CONCLUSION AND DISCUSSION: These finding suggest that analysis of construct issues in research articles is a more advanced skill than analysis of research design and that critical appraisal of research literature is enhanced by clinical experiences related to the subject of the research report.

Physical Therapy Modalities↗
PubMed1993

Combined analysis of tall fescue steer grazing studies in the Eastern United States.

The mixed-models procedure (MMP) was used to analyze pooled data sets from 12 independent studies conducted during the last 13 yr at nine locations in seven states to provide combined estimates of daily gains by beef steers (Bos taurus) grazing tall fescue (Festuca arundinacea Schreb.) pastures free of (E-) or infested (E+) at different levels with the endophytic fungus Acremonium coenophialum. Treatments included low-infestation (< or = 5% E+), moderate-infestation (> or = 20 to < or = 35% E+), and high-infestation (> or = 50 to < or = 97% E+) tall fescue pastures, and, in tall fescue-clover (Trifolium spp.) mixtures, pastures at the same E+ levels with approximately 25 and 10% clover in spring and summer stands, respectively. Spring, summer, and combined spring+summer data were analyzed separately. The MMP permitted estimation of the fixed effects of treatments over a broad inference space of future years and different tall fescue pastures over a wide geographic range; detected relationships that had not been apparent in the individual studies, such as the interactions between clover presence and E+ infestation levels; and provided a more coherent body of information than did the results obtained from each discrete study. Logistical and financial constraints that force undesirable compromises in the conduct of future grazing and other expensive or time-consuming research may be avoided by using MMP within the context of cooperative projects.

Acremonium↗
PubMed1993

Operative laparoscopy. American Association of Gynecologic Laparoscopists 1991 membership survey.

The American Association of Gynecologic Laparoscopists 1991 membership survey on operative laparoscopy had a total of 878 respondents reporting 56,536 procedures, for a 1.5-fold increase over the number of procedures reported in 1988. The most frequent indication was pelvic pain (58% of procedures); next was infertility (42%). Laparoscopic management of ectopic pregnancy increased over twofold, from 1,914 cases in 1988 to 4,620 in 1991. As compared to the 1988 survey data, the rate of unintended laparotomy to manage hemorrhage, bowel or urinary tract injury may have increased, but the death rate remained low, 1.8 per 100,000 procedures.

Female↗