Search PubMed⌕ Search

Biomedical subjects

B Campbell

Publications and source records attributed to B Campbell.

At least 91 records · Page 5Linked to original sources
PubMed1996

Time course of endothelial dysfunction and neutrophil adherence and infiltration during murine traumatic shock.

Traumatic shock in rats has been shown to induce endothelial dysfunction, and to increase intestinal myeloperoxidase activity (MPO) indicative of neutrophil infiltration. To examine the time course of endothelial dysfunction and neutrophil adherence and infiltration, pentobarbital anesthetized rats, subjected to Noble-Collip drum trauma, were studied prior to and 15, 30, 60, 90, 120, 150, and 180 min following drum trauma. Superior mesenteric artery rings obtained from traumatized rats were tested for responsiveness to acetylcholine (ACh), a receptor-mediated endothelium-dependent vasodilator, and to NaNO2 an endothelium-independent vasodilator. ACh-induced relaxation was not impaired immediately after the induction of trauma (time 0). However, 15-30 min after trauma, responses to ACh were significantly depressed (p < .05) and were further reduced (p < .01) 90-180 min after trauma. No significant changes occurred in response to the direct vasodilator NaNO2 at any of the times studied, indicating no vascular smooth muscle injury. Moreover, the adherence of polymorphonuclear leukocytes (PMNs) to the post-traumatic mesenteric vascular endothelium also showed an increase that peaked 30 min post-trauma. Intestinal MPO activity, indicative of neutrophil infiltration, was characterized by a continuous and sustained increase from 30-180 min. Our findings suggest that endothelial dysfunction resulting in reduced NO release occurs in the early phase of murine traumatic shock, and that this phenomenon is followed by a time-dependent increase in adhesivity of neutrophils to the vascular endothelium leading to a progressive accumulation of PMNs in injured tissues (e.g., intestine).

Animals↗
PubMed1996

Effects of defibrotide on leukocyte-endothelial cell interaction in the rat mesenteric vascular bed: role of P-selectin.

The effects of defibrotide on leukocyte-endothelial cell interaction and P-selectin surface expression on the microvascular endothelium were investigated. Intravital microscopy was performed in the rat mesenteric microcirculation. The rat mesentery was superfused either with Krebs-Henseleit solution (i.e., control) or 50 microM NG nitro-L-arginine methyl ester (L-NAME). Defibrotide (40 mg/kg) was intravenously infused to control rats and to L-NAME superfused rats. P-selectin expression on mesenteric venules was also investigated by immunohistochemistry. L-NAME caused a significant, time-dependent increase in leukocyte rolling (13 +/- 5 to 101 +/- 18 cells/ min; p < 0.001) and adherence (1.6 +/- 0.7 to 12 +/- 2.5 cells/100 microns length of venule; p < 0.01) compared to control superfused rats. However, intravenous infusion of defibrotide (40 mg/kg) consistently decreased the L-NAME-induced leukocyte rolling (101 +/- 18 to 9.3 +/- 1.3 cells/min; p < 0.001) and adherence (12 +/- 2.5 to 1.9 +/- 1.1 cells/100 microns length of venule; p < 0.01). Exposure of rat mesentery to L-NAME consistently increased P-selectin surface expression (p < 0.01) on the vascular endothelium which was significantly attenuated by defibrotide (p < 0.05). In vivo administration of defibrotide can reduce leukocyte rolling and adherence in the mesenteric rat microvasculature by attenuating P-selectin expression. Since P-selectin was upregulated by the specific nitric oxide synthase inhibitor L-NAME, the present study also confirms the crucial role exerted by nitric oxide in attenuating leukocyte-endothelial cell interaction during various pathophysiological conditions.

Animals↗
PubMed1995

Deglutitive aspiration in patients with tracheostomy: effect of tracheostomy on the duration of vocal cord closure.

BACKGROUND/AIMS: Deglutitive aspiration in patients with tracheostomy has been attributed to impaired laryngeal movement, loss of protective laryngeal reflexes, and uncoordinated laryngeal closure. The aim of this study was to determine the effect of tracheostomy on the duration of deglutitive vocal cord closure. METHODS: Using concurrent videoendoscopy, respirography, and submental electromyography, deglutitive vocal cord closure and its temporal relationship with deglutitive apnea was compared between patients with tracheostomy and normal volunteers. RESULTS: Between-group comparison showed that the duration of vocal cord adduction/abduction in patients with tracheostomy was significantly shorter than that of normal volunteers (P < 0.05). Contrary to normal volunteers, in patients with tracheostomy, 5-mL water swallows significantly increased the duration of vocal cord adduction/abduction compared with that of dry swallows (P < 0.05). In addition, in patients with tracheostomy, deglutitive apnea and submental electromyography were not coordinated with vocal cord kinetics. CONCLUSIONS: Although the vocal cords close completely during swallowing in patients with tracheostomy, their duration of closure is significantly shorter compared with normal volunteers. Coordination of deglutitive vocal cord kinetics, apnea, and submental electromyography is altered in patients with tracheostomy. Contrary to normal controls, duration of deglutitive vocal cord closure in patients with tracheostomy is modified by the presence of liquid bolus.

Adult↗
PubMed1995

Influenza and pneumococcal vaccination and tuberculin skin testing programs in long-term care facilities: where do we stand?

OBJECTIVE: 1) To compare policies and procedures for distribution of influenza and pneumococcal vaccines to long-term care facilities for the elderly in Canada, 2) to determine vaccination rates of residents and staff, and 3) to describe vaccination and tuberculin skin testing programs in these facilities. DESIGN: A cross-sectional survey consisting of telephone interviews and a mailed questionnaire was conducted in the spring of 1991. Telephone interviews were conducted with provincial/territorial epidemiologists. The questionnaire was sent to all (N = 1.520) Canadian long-term care facilities for the elderly with > or = 25 beds. RESULTS: There were 1,270 responding facilities (84%). The mean overall influenza vaccination rate for residents was 78.5%. The mean vaccination rate was higher in those provinces in which the vaccine was paid for by the government (79% versus 71%; P = 0.002). Only 19% of facilities reported staff vaccination rates > 25%; rates again were higher in those provinces in which vaccine for staff was provided by the government. Pneumococcal vaccine was offered to residents in 12% of the facilities. The proportions of facilities with > 10% and > 75% of residents vaccinated were significantly higher in the provinces where the pneumococcal vaccine was recommended and paid for as compared with those where it was not (P < 0.001 for both). Tuberculin skin testing programs for residents existed in 360 long-term care facilities (28%) across the country. CONCLUSION: In 1990, the number of residents living in Canadian long-term care facilities who were vaccinated against influenza and Streptococcus pneumoniae was suboptimal. Staff influenza vaccination rates were very low across the country. Most facilities did not have a baseline tuberculin skin test status for their residents. Vaccination rates are higher in jurisdictions in which governments provide the vaccine without charge.

Bacterial Vaccines↗
PubMed1995

Oral kinetics of dexfenfluramine and dexnorfenfluramine in non-human primates.

1. Large doses of dexfenfluramine in animals cause a decrease of serotoninergic markers but none of the species so far investigated shows sufficient kinetic and metabolic similarity with man to be a valid model for safety studies. The plasma kinetics of dexfenfluramine and its active metabolite dexnorfenfluramine were therefore studied in baboon, rhesus and cynomolgus monkeys given dexfenfluramine hydrochloride orally (2 mg/kg) in order to investigate whether any of these primates have a biodisposition particularly similar to man. 2. The drug was rapidly N-deethylated to dexnorfenfluramine achieving comparatively low mean maximum plasma levels (Cmax) of 12-14 ng/ml in all primates, and rapidly disappeared thereafter with half-lives (t1/2) ranging from 2 to 3 h in the baboon and rhesus monkey to 6 h in the cynomolgus monkey. Its normetabolite reached higher mean Cmax (52-97 ng/ml) and the t1/2's were longer, varying from about 11 h in the rhesus monkey to 22 h in the cynomolgus monkey. The metabolite-to-parent drug ratio (14-37), in terms of plasma area under curve (AUC), greatly exceeded that in man (< 1), being higher than in all species investigated so far. 3. Comparative repeat dose simulation in monkey and man indicated that the dosage in primates would need to be increased 10-fold to achieve comparable dexfenfluramine steady-state plasma Cmax, producing nor-metabolite levels several times those in man, whilst for comparable metabolite Cmax, those of the parent drug would be correspondingly too low. 4. In view of the different mechanism of action of dexfenfluramine and dexnorfenfluramine within the serotoninergic system none of these primates is therefore a suitable model for safety assessment in terms of exposure of the active moieties in comparison with man.

Animals↗
PubMed1995

Sublingual and oral morphine administration. Review and new findings.

Clinical reports rave about the efficacy of sublingual morphine, but most research data suggest that sublingual morphine lacks the necessary physical characteristics to be absorbed through sublingual tissues. This article clarifies these assertions by reviewing the clinical literature that supports sublingual administration, the theories relevant to sublingual morphine administration, and the pharmacokinetic research that supports or negates the benefit of this route. Recommendations for clinical nursing practice are provided to guide decision-making in care of patients with cancer pain.

Absorption↗
PubMed1994

Testosterone and religiosity as predictors of sexual attitudes and activity among adolescent males: a biosocial model.

A biosocial model of the effects of early adolescent testosterone levels and religiosity on adolescent males' sexual attitudes and activity over a 3-year period was examined. Using panel data for approximately 100 boys who were 12.5/13.0 years old at study entry, significant additive effects of free testosterone and frequency of attendance at religious services were demonstrated on the transition to first intercourse and other aspects of sexual behaviour and attitudes. No interactive effects of the two predictors were found. Boys with higher free testosterone levels at study entry who never or infrequently attended religious services were the most sexually active and had the most permissive attitudes. Boys with lower free testosterone who attended services once a week or more were the least active and reported the least permissive attitudes. For some behaviours, differences between free testosterone/attendance groups increased over time, resulting in substantial behavioural differences by the final round of measurement 3 years later.

Adolescent↗
PubMed1994

Sexual behaviour and HIV knowledge among adolescent boys in Zimbabwe.

A study on sexual behaviour and knowledge of HIV risk was undertaken amongst 511 male students in Zimbabwe. The study was conducted amongst pupils aged 11 to 19 years drawn from urban and rural secondary schools using a self-administered questionnaire. Thirty seven pc of the students reported that they had experienced sexual intercourse, with up to 63 pc reporting having had more than one partner. Twenty one pc of boys aged 12 years reported having had intercourse and the proportion increased with age. Knowledge about AIDS was high (93 pc) with up to 75 pc of the boys reporting that they received the information through the media and only 31 pc got it from their teachers. Logistic regression used to analyse reasons for variation in HIV/AIDS knowledge and of modes of its transmission determined that educational level, actual school attended, access to information from magazines and educational aspirations were significant predictors (p values = 0,005) of knowledge. Individual risk assessment was higher amongst students who reported sexual experience (p = 0,0001). Sixty pc of the sexually experienced boys reported having used condoms. Six pc of the boys reported having intercourse with a commercial sex worker and of these, 85 pc used condoms. Compared with previous studies there appeared to be a reduction in high risk behaviours amongst male secondary school students. However, there is need for increased HIV preventive information through school educational programmes, as increase and variation in HIV information and modes of transmission was seen depending on access to information.

Adolescent↗
PubMed1994

Soft-tissue reconstruction of the oral cavity.

In our early experience with head and neck reconstruction, we evaluated our results mainly by the final contour of the mandible. With further experience, the bony reconstruction has become more and more accurate, and it is the intraoral soft-tissue reconstruction that poses the continued challenge. Better preoperative and postoperative evaluation will improve our operative planning, and our results will continue to improve. We must be able to compare our cases with those of other centers by appropriately categorizing deficits into specific structures removed to allow relevant comparison of results. We should no longer accept the simple view of the oral cavity deficit as a uniform soft-tissue loss that requires nothing more than closure. Nor can we continue to accept the evaluation of postoperative results of head and neck reconstruction by a simple external photograph; rather, this must be combined with a true visual and functional assessment of the oral cavity. In this way, the combined effort of head and neck surgeons will help to advance the cause of oral cavity reconstruction as rapidly as has occurred with reconstruction of the mandible.

Humans↗
PubMed1993

Partial agonist activity of celiprolol.

Celiprolol given intravenously (i.v.) to pithed rats in the dose range of 0.1-10,000 micrograms/g produced a dose-dependent increase in heart rate (HR) which was greatest (123 beats/min) at 1,000-3,000 micrograms/kg. This partial agonist effect was blocked by the selective beta 1-adrenoceptor antagonist CGP 20712A. Celiprolol also produced a vasodepressor effect in this dose range which was abolished by the relatively selective beta 2-adrenoceptor antagonist ICI 118551 but not CGP 20712A. The magnitude of this intrinsic sympathomimetic activity (ISA) response was not significantly altered by reserpine pretreatment. Celiprolol also antagonised the effects of isoprenaline 0.05 microgram/kg on HR and blood pressure (BP). The beta 1 selectivity of celiprolol as an antagonist in pithed rats (beta 1/beta 2 = 340:1) was similar to that observed in studies with isolated guinea pig atria and trachea (beta 1/beta 2 = 63:1), both being considerably greater than that observed with atenolol. Celiprolol, however, like atenolol, potentiated the bronchoconstrictor responses to histamine (3 micrograms/kg). Metabolic studies of rats and human urine failed to show significant amounts of potentially vasoactive metabolites. These data are consistent with celiprolol acting as both a beta 1- and beta 2- adrenoceptor partial agonist.

Adrenergic beta-Antagonists↗
PubMed1993

Lead poisoning.

While lead is a very old poison whose toxicity was known to the ancient Greeks, new information about mechanisms and effects of lead toxicity is continually being discovered. Family practitioners should be alert to the possibility of lead poisoning and the situations in which it occurs. Symptoms may be non specific and careful questioning of patients or their parents may be required to identify possible exposure.

Absorption↗
PubMed1992

Utility of squamous cell carcinoma antigen (SCC Ag) as a tumour marker in pulmonary malignancy.

Squamous cell carcinoma antigen (SCC Ag), a recently developed tumour marker, has shown some promise, particularly in squamous cell carcinoma (SCC) of the uterine cervix. To evaluate its usefulness in SCC of the lung, serum SCC Ag levels were measured in 52 patients with a variety of respiratory diseases (both benign and malignant), 17 patients with renal failure and 56 healthy controls. SCC Ag was elevated in 11 of 25 patients with SCC lung and one patient with a mixed adeno-squamous tumour, but in no patients with other malignancies or benign respiratory disease. SCC Ag levels appeared unrelated to either tumour stage or the degree of differentiation. False-positive results were noted in patients with renal failure, with six of eight patients with a plasma creatinine greater than 0.7 mmol l-1 having an elevated SCC Ag level. Because SCC Ag was highly specific in the presence of normal renal function, an elevated level would support early investigation of a patient with suspected pulmonary malignancy. The potential of SCC Ag in typing large cell lung carcinomas (where light microscopic features of SCC are uncertain) warrants further investigation.

Antigens, Neoplasm↗