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Biomedical subjects

J Morrison

Publications and source records attributed to J Morrison.

At least 73 records · Page 4Linked to original sources
PubMed1999

Comparison of gingival and peripheral blood T cells among patients with periodontitis suggests skewing of the gingival T cell antigen receptor V beta repertoire.

The present study investigated the expression of different variable regions of T cell receptor beta-chain (V beta) among functional subsets of T cells, i.e. CD45RO+ (activated/memory), CD4+ and CD8+ in gingiva and peripheral blood of patients with periodontitis. Gingival tissue specimens (n = 25) and peripheral blood were procured from 18 patients with periodontitis during periodontal surgery or extraction. Single-cell suspensions of gingival tissues were made by enzymatic digestion. These cells were immunofluorescently labeled with a panel of monoclonal antibodies specific for 18 TCR V beta regions, in concert with markers for various T cell subsets. The cells were then analyzed with 3-color multivariate flow cytometry. Results demonstrated that a significantly higher proportion of T cells in gingiva expressed V beta 5.2 (0.0005), V beta 6 (0.0007) and V beta 9 (0.003) regions compared to those in peripheral blood. Comparison of CD45RO+ (activated/memory) and CD45RO- (naïve) subsets of gingival T cells revealed differences in the expression of TCR V beta regions. V beta 5.2 expression was significantly higher among CD45RO+ gingival T cells (p = 0.004), whereas V beta 14 expression was elevated among the CD45RO- subset relative to peripheral blood (p = 0.008). Analysis of TCR V beta region expression among CD4+ and CD8+ subsets did not reveal any statistically significant differences between gingiva and peripheral blood, although some V beta regions approached significance. Collectively, these results demonstrate that the T cell repertoire in the gingival compartment differs significantly from that in the peripheral blood. Furthermore, since the skewing of TCR V beta was observed among naïve, as well as activated/memory T cells, it is likely that both developmental and environmental factors are influential in shaping the gingival TCR repertoire in patients with periodontitis. Elucidation of the cause of the skewed expression of T cell receptors in gingiva can provide insights into the specificity of T cells in periodontitis.

Adult↗
PubMed1999

Proficiencies of three anaerobic culture systems for recovering periodontal pathogenic bacteria.

Anaerobic culture is employed routinely in the primary isolation of periodontal pathogenic bacteria. However, little or no data exist on the relative abilities of the Coy anaerobic chamber (Coy Laboratory Products, Grass Lake, Mich.), the GasPak (Becton Dickinson Microbiology Systems, Cockeysville, Md.), and the AnaeroPack (Mitsubishi Gas Chemical America, Inc., New York, N.Y.) systems to grow important periodontal species, including Porphyromonas gingivalis, Prevotella intermedia/nigrescens, Bacteroides forsythus, Eubacterium species, Campylobacter species, Fusobacterium species, and Peptostreptococcus micros. A total of 78 specimens from advanced periodontitis lesions were collected anaerobically, plated on enriched blood agar medium, and incubated at 35 degrees C for 5 to 7 days in each anaerobic culture system. The three culture systems were equally efficient in isolating Porphyromonas gingivalis and Prevotella intermedia/nigrescens. The Coy anaerobic chamber yielded the highest proportional recoveries of Campylobacter (P = 0.0001; nonparametric analysis of variance) and Eubacterium (P = 0.009). The Coy anaerobic chamber and the GasPak system demonstrated higher proportional recoveries of Bacteroides forsythus (P = 0.0006) and Peptostreptococcus micros (P = 0.0001) than the AnaeroPack system. The AnaeroPack system was most efficient in growing Fusobacterium species (P = 0.0001). Overall, the Coy anaerobic chamber and the GasPak system showed the highest proportional recoveries of putative periodontal pathogens, but the recoveries by the various anaerobic test systems varied considerably from sample to sample.

Adult↗
PubMed1999

Assessment of a simple scoring system applied to a screening questionnaire of asthma in children aged 5-15 yrs.

The aim of the present study was to validate a simple scoring system using a parent-completed screening questionnaire to identify children aged 5-15 yrs who may have asthma. A stratified random sample of 157 children of 1,808 whose parents had answered a postal respiratory questionnaire underwent detailed clinical evaluation. The results were reviewed by three independent paediatricians whose opinions were combined to reach, for each child, decisions regarding three standards: 1) "possible asthma" defined as >50% likelihood of having asthma; 2) "possible asthma" defined as meriting a clinical trial of asthma medication; and 3) "probable asthma" defined as >90% likelihood of having asthma. The combined decisions were compared to three sets of questionnaire scores, in order to determine the positive predictive value, sensitivity and specificity of each set in identifying children with probable/possible asthma. The three sets of chosen questionnaire scores all had positive predictive values of 79-96% for predicting possible asthma, using either the combined expert opinion ">50% likelihood of asthma" or that of "warrants a trial of treatment" as the definition. This suggests that a low proportion of false positives would be obtained were this scoring system to be used for a screening programme. The combined decision >90% chance of asthma could be used as a means of estimating prevalence of asthma in the survey. When used for this, the prevalence of asthma in the surveyed population was 18.8% (95% confidence interval 13.1-26.3). In conclusion, the present scoring system, based on a simple respiratory questionnaire, provides a valid method of identifying children likely to have asthma, and who, if unknown to the medical services, would benefit from clinical review.

Adolescent↗
PubMed1999

Activation of pelvic afferent nerves from the rat bladder during filling.

This short paper has reviewed current information on the physiology of bladder mechanoreceptors. Afferents in the bladder mucosa appear to be sensitive to distension but not to contraction of the viscus, and are also sensitive to the chemical composition of the bladder contents. Evidence is provided that suggest that Neurokinin A is released from primary afferent endings in the submucosa and is involved in both the normal response to distension, and the sensitization process. The results suggest that the low threshold mechanoreceptors are polymodal, and are modulated by various mediators, including some peptides that may originate from the sensory endings themselves, and that these mediators may be active during normal filling.

Afferent Pathways↗
PubMed1999

Out-patient and home-parenteral antibiotic therapy (OHPAT): evaluation of the impact of one year's experience in Tayside.

OBJECTIVE: An out-patient and home parenteral antibiotic therapy programme for the treatment of suitable infections was developed over a four year period. This paper describes the impact of one year's experience of its implementation on various measures of outcome. DESIGN: Each patient treatment has a full integrated care pathway (ICP) and patient satisfaction questionnaire completed. The ICP documents the clinical progress of the patient and incorporates various measures of quality of care on the 101 number of patients treated from April 1998 to March 1999 are presented here. SETTING: Dundee Teaching Hospitals NHS Trust (now Tayside University Hospitals NHS Trust). SUBJECTS: Patients with a range of infections requiring intravenous antibiotics. MAIN MEASURES: Number of patients treated with various infections, clinical and microbiological outcome, drug and vascular access complication rates, impact on drug costs and in-patient bed days, and measurement of patient satisfaction/quality of life. RESULTS: Patients were treated over a 12 month period. 51.5 per cent had skin & soft tissue infections and 22.8 per cent bone & joint sepsis. 57 per cent of patients received out-patient and 34 per cent self or carer administered home therapy. Ninety-four per cent of patients were cured or improved following treatment. Only 7.5 per cent of patients required an unscheduled admission to hospital. Twelve per cent of patients had some type of vascular device related adverse event (partly due to a faulty batch of lines) and six per cent of patients had a drug related reaction. The additional daily cost of drugs was minimal (< 12 Pounds/day) and more than 1,461 bed days have been saved across the Directorates. The patient satisfaction level was high.

Ambulatory Care↗
PubMed1998

Physicians disciplined by a state medical board.

CONTEXT: State medical boards discipline several thousand physicians each year. Although certain subgroups, such as those disciplined for malpractice, substance use, or sexual abuse, have been studied, little is known about disciplined physicians as a group. OBJECTIVE: To assess the offenses, contributing factors, and type of discipline of a consecutive series of disciplined physicians. DESIGN: Case-control study on publicly available data matching 375 disciplined physicians with 2 groups of control physicians, one matched solely by locale, and a second matched for sex, type of practice, and locale. SUBJECTS: All disciplined physicians publicly reported by the Medical Board of California from October 1995 through April 1997. MAIN OUTCOME MEASURES: Characteristics of disciplined physicians, offenses leading to discipline, and type of discipline. RESULTS: A total of 375 physicians licensed by the Medical Board of California (approximately 0.24% per year) were disciplined for 465 offenses. The most frequent causes for discipline were negligence or incompetence (34%), abuse of alcohol or other drugs (14%), inappropriate prescribing practices (11%), inappropriate contact with patients (10%), and fraud (9%). Discipline imposed was revocation of medical license (21%), actual suspension of license (13%), stayed suspension of license (45%), and reprimand (21%). Type of offense was significantly associated with severity of discipline (P=.03). In logistic regression models comparing disciplined physicians with controls matched by locale, board discipline was significantly associated with physicians' sex (odds ratio [OR] for women, 0.44; 95% confidence interval [CI], 0.28-0.70) and involvement in direct patient care (OR, 2.56; 95% CI, 1.75-3.75). In the regression model with additional matching criteria, disciplinary action was negatively associated with specialty board certification (OR, 0.42; 95% CI, 0.29-0.60) and positively associated with being in practice more than 20 years (OR, 2.02; 95% CI, 1.39-2.92). CONCLUSIONS: A small but substantial proportion of physicians is disciplined each year for a variety of offenses. Further study of disciplined physicians is necessary to identify physicians at high risk for offenses leading to disciplinary action and to develop effective interventions to prevent these offenses.

California↗
PubMed1998

Footwall refrigeration along a detachment fault: implications for the thermal evolution of core complexes

Oxygen isotope compositions of epidote and quartz from chloritic breccias that underlie the detachment fault in the metamorphic core complex of the Whipple Mountains yielded quartz-epidote fractionations that range from 4.1 to 6.4 per mil and increase systematically toward the fault. These fractionations give mean temperatures that decrease from approximately 432 degrees C at 50 meters below the fault to approximately 350 degrees C at 12 meters below the fault. This extreme thermal gradient of 82 degrees C over 38 meters (2160 degrees C per kilometer) is best explained by advective heat extraction by means of circulating surface-derived fluids. Models of lithospheric extension consider only conductive cooling resulting from tectonic denudation and thus require revision to include fluid-induced fault-zone refrigeration.

Journal Article↗
PubMed1998

Synergistic effect between IL-10 and bcl-2 genotypes in determining susceptibility to systemic lupus erythematosus.

OBJECTIVE: To determine whether genes participating in programmed cell death, including bcl-2, IL-10, Fas-L, and CTLA-4, may contribute to the genetic predisposition to systemic lupus erythematosus (SLE). METHODS: First, intragenic markers for the bcl-2, IL-10, Fas-L, and CTLA-4 genes were characterized and their extent of polymorphism in normal populations was determined. The allelic distribution of these gene markers in a large Mexican American SLE cohort of 158 patients and 223 ethnically matched controls was determined using fluorescent-labeled primers and semiautomated genotyping. RESULTS: The bcl-2, Fas-L, and IL-10 loci showed significantly different allelic distribution in SLE patients compared with controls, indicating an association between these genes and SLE. No association was found between SLE and the CTLA-4 gene. Further analysis revealed a synergistic effect between susceptibility alleles of the bcl-2 and IL-10 genes in determining disease susceptibility. Alone, the presence of each of these alleles was associated with a moderate increase in SLE risk, while the occurrence of these alleles together increased the odds of developing SLE by more than 40-fold. CONCLUSION: The results suggest that individuals carrying specific genotypes of both bcl-2 and IL-10 are at significant risk of developing SLE.

Abatacept↗
PubMed1998

Alterations in renal microcirculation during cardiopulmonary bypass.

BACKGROUND: This study was designed to investigate renal microvascular changes during cardiopulmonary bypass. METHODS: Kidneys were harvested from each of four groups of 6 pigs. Group A were anesthetized and heparinized only. The remaining three groups underwent cardiopulmonary bypass at 28 degrees C, group B for 30 minutes and groups C and D for 120 minutes; group D had an additional 30 minutes of normothermic perfusion at the end of the experiment. Renal cortical blood flow was measured using radiolabeled microspheres. Microvascular morphology was defined by corrosion casting and scanning electron microscopy. RESULTS: In group A, renal vascular resistance was 61+/-5.1 mm Hg x mL(-1) x min(-1). This value decreased to 28+/-7.8 in group B and 25+/-4.0 in group C (p < 0.05), and increased in group D to 40+/-4.1 (p < 0.05 versus groups A, B, and C). Cortical thickness, as measured by microvascular casts in groups A, B, and C, was 33, 34, and 31 mm, respectively, with equal distribution of the resin to the superficial and deep cortex but was significantly reduced in group D to 22 mm (p < 0.05 versus groups A, B, and C), with failure of the resin to fill the superficial cortical layer. Diameters of glomeruli as seen on the casts were 111+/-10.38 microm in group A, 100+/-9.24 microm in group B, and 82+/-4.4 microm in group C (p < 0.05 group A versus group C). The glomeruli from group D were still significantly smaller than group A (93+/-10.35 microm, p < 0.05). Mean glomerular capillary diameters were 4.65+/-0.26 microm in group A, 3.9+/-0.16 microm in group B, 3.6+/-0.19 microm in group C, and 3.65+/-0.3 microm in group D (p < 0.05 group A versus groups B, C, and D). CONCLUSIONS: Hypothermic nonpulsatile cardiopulmonary bypass decreased renal vascular resistance, but the superficial and deep layers of the cortex were perfused equally. Glomeruli were reduced in size because of capillary narrowing. This was consistent with diversion of blood through bypass channels. With restoration of normothermia, underperfusion of the superficial cortex occurred, with potential for damage to these nephrons during the increased metabolic demands of rewarming.

Anesthesia, Inhalation↗
PubMed1998

Prolonged myocardial hibernation exacerbates cardiomyocyte degeneration and impairs recovery of function after revascularization.

OBJECTIVES: We sought to define the effects of time on contractile function, morphology and functional recovery after coronary revascularization in patients with dysfunctional but viable (hibernating) myocardium. BACKGROUND: Functional recovery after coronary artery bypass graft surgery in patients with chronic myocardial hibernation is incomplete or delayed. The proposed cause is a progressive temporal degeneration of cardiomyocytes. METHODS: In 32 patients with multivessel coronary disease, regional wall motion analysis was performed in hypoperfused but metabolically active areas before and 6 months after bypass surgery. During bypass surgery, transmural biopsy samples were obtained from the center of the hypokinetic zone for light and electron microscopic analyses. The proposed duration of myocardial hibernation was retrospectively assessed. RESULTS: Patients with a subacute hibernating condition (<50 days) demonstrated a higher preoperative ejection fraction (EF, 50+/-8%), and a better preserved wall motion (WM) in the supraapical wall (-1.4+/-0.4) than did patients with intermediate-term (>50 days, EF 37+/-9%, p < 0.05; WM -2.4+/-1.5, p = 0.08) or chronic (>6 months, EF 40+/-14%, WM -2.7+/-0.9, p < 0.005) ischemia. Structural degeneration correlated with the duration of ischemia (r = 0.56, p < 0.05). Postoperative recovery of function was enhanced in patients with a short history of hibernation compared with patients with an intermediate-term or chronic condition (EF 60+/-10% vs. 40+/-10%, p < 0.001, and vs. 47+/-14%, p < 0.05). CONCLUSIONS: Hibernating myocardium exhibits time-dependent deterioration due to progressive structural degeneration with enhanced fibrosis. Early revascularization should be attempted to salvage the jeopardized tissue and improve postoperative outcome.

Aged↗
PubMed1998

Clinical issues surrounding the use of terbutaline sulfate for preterm labor.

beta-mimetics have been prescribed by physicians to arrest or prevent premature labor for more than 20 years. Although not approved by the Food and Drug Administration (FDA) for tocolytic use, terbutaline sulfate has been the most widely prescribed beta-mimetic in the United States. Recently, the role of terbutaline in the treatment and prevention of preterm labor has been questioned by the FDA. Because the off-label use of drugs is a formally accepted practice in medicine when scientific studies support such use, we reviewed the currently available clinical literature on terbutaline use in various routes of delivery: intravenous, oral, and subcutaneous via infusion pump. This review describes the clinical evidence that supports the safe and effective use of terbutaline as a tocolytic agent in certain patient populations. Practicing physicians should continue to have unrestricted use of terbutaline for tocolysis as one of the few remaining therapeutic options remaining in the fight against preterm birth.

Administration, Oral↗
PubMed1998

A staffing model based on workload in three VA mental health clinics.

In the era of managed care, agencies that provide mental health care can cope with the increasing volume of patients and the increasing severity of their conditions by having a variety of mental health professionals provide services. A model for determining workforce needs for outpatient mental health clinics is described. The model was used with workload data from three Veterans Affairs clinics to determine that two psychiatrists and five or six nonpsychiatrists should be able to evaluate 400 new patients a year and provide ongoing care for 2,300 patients a year in such settings. The method can be adapted to determine workforce needs for other outpatient clinical settings.

California↗
PubMed1998

Clinical and microbiological evaluation of a bioabsorbable and a nonresorbable barrier membrane in the treatment of periodontal intraosseous lesions.

Clinical and microbiological features of periodontal healing in barrier membrane-treated sites were determined in a randomized clinical trial. The study included 10 patients with advanced adult periodontitis and a minimum of one set of similar 2 to 3 wall intraosseous periodontal lesions with no furcation involvement. In each patient, one periodontal lesion was treated with a biodegradable membrane and a contralateral lesion with a nonresorbable barrier membrane. Within the preceding 3 months of regenerative therapy, all patients received full mouth osseous surgery except for the sites for regeneration, were instructed in oral hygiene, and were prescribed systemic ciprofloxacin and metronidazole (250 mg of each, TID, 8 days), starting 7 days before membrane placement. At baseline and at 6 months postsurgery, probing depth and clinical attachment level were assessed in each study site. The subgingival presence of suspected periodontal pathogens was determined by non-selective and selective culture and by DNA probe analyses, and of human cytomegalovirus (HCMV) and Epstein-Barr virus type 1 (EBV-1) by a nested-polymerase chain reaction detection method. At baseline, the barrier-treated sites did not differ significantly in clinical and microbial parameters. Mean baseline probing depth was 7.8+/-1.1 mm for bioabsorbable and 7.9+/-1.3 mm for nonresorbable barrier-treated sites. At 6 months, sites treated with bioabsorbable barrier revealed 4.6+/-1.7 mm gain of clinical attachment (range: 1 to 7 mm) and sites treated with nonresorbable barrier 4.2+/-2.0 mm (range: 1 to 8 mm). The 11 barrier-treated sites that harbored 10% or less bacterial pathogens and were free of HCMV and EBV-1 averaged significantly more clinical attachment gain than the 9 sites that yielded more than 10% bacterial pathogens and/or test viruses (5.6 mm versus 3.0 mm; P=0.005). The present data suggest bioabsorbable and nonresorbable barriers provide similar clinical healing of 2 to 3 wall intraosseous periodontal lesions, emphasize the importance of controlling bacterial pathogens prior to and during periodontal healing, and point to the possible detrimental role of HCMV and EBV-1 in periodontal repair.

Adult↗
PubMed1997

The effects of cardioplegic arrest and reperfusion on the microvasculature of the heart.

OBJECTIVES: Despite laboratory evidence of leucocyte involvement in reperfusion injury, cardiac surgical clinical trials do not support the therapeutic effectiveness of leucocyte filtration. Furthermore, the direct effects of crystalloid cardioplegia and reperfusion on the capillaries of the heart have yet to be elucidated. We tested the effects of cardioplegic arrest and reperfusion both with and without leucocyte depletion, in a model of cardiopulmonary bypass that mimics clinical cardiac surgical conditions. METHODS: Four groups of Landrace pigs were studied. Group A (n = 6) underwent 30 min of hypothermic (28 degrees C) cardiopulmonary bypass. Groups B (n = 6), C (n = 6) and D (n = 6) also had 90 min of cardioplegic arrest. Group C was then reperfused with whole blood, while Group D was reperfused with leucocyte-depleted blood. Microvascular methylmethacrylate corrosion casts were made at the end of the experimental period. Myocardial vascular anatomy was defined by electron microscopy and capillary abundance derived from this and from the weight of casts from representative areas. Leucocyte deposition was assessed using radioisotope-labelled leucocytes. Ischaemic damage to tissues was graded according to light and electron microscopic findings. RESULTS: In Group A the mean (+/- S.D.) vascular cast weight/volume of myocardium (density) was 125 +/- 9 mg/mm3. After cardioplegic arrest (Group B), it fell to 74 +/- 7 mg/mm3 (P < 0.0001) due to absence of capillaries, although arterioles, venules and non-nutritive bypass vessels remained patent. Following reperfusion with whole blood (Group C), capillary numbers partially recovered but luminal diameters were reduced with a cast density of 94 +/- 5 mg/mm3 (P < 0.0001 versus Group A and B). Leucocyte-depleted (87-92%) reperfusion in Group D did not affect cast density (90 +/- 3 mg/mm3; P = 0.17). Coronary vascular resistances in Groups C and D rose slightly, but not significantly, during reperfusion. CONCLUSIONS: Following cardioplegic arrest, microvascular changes are marked. These changes are partially reversed by 30 min reperfusion. Leucocyte depletion does not ameliorate these effects in this model.

Animals↗
PubMed1997

Vertical transmission of human immunodeficiency virus.

We discuss the interactions between mother and infant that influence the transmission of HIV. Potential routes of infection are identified, and maternal and infant risk factors for transmission are explored. The role of the immune system in controlling HIV infection in the infant is discussed. Finally, preventive measures for reducing vertical transmission are proposed and evaluated.

Anti-HIV Agents↗