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Biomedical subjects

R Bell

Publications and source records attributed to R Bell.

At least 181 records · Page 10Linked to original sources
PubMed1994

5-HT1A receptor influences on rodent social and agonistic behavior: a review and empirical study.

Investigations examining the influence of 5-HT1A receptors in murine agonistic and social behavior have reported either specific or nonspecific attenuation of offensive behavior. To clarify this situation, the effects of three 5-HT1A agonists were examined on isolation-induced aggression and social behavior in male mice. 8-OH-DPAT (0.025-1.25 mg/kg) increased social behavior, rearing, and digging. Offensive behavior was reduced, without concomitant sedation. Ipsapirone (0.1-10.0 mg/kg) reduced naso-nasal behavior, whilst enhancing stretched-attend behavior, cage-exploration, and rearing. Offensive and defensive behaviors were attenuated, without reductions in activity. MDL 73005 EF (0.25-8.0 mg/kg) reduced social behaviors, cage-exploration and rearing while maintenance behavior was increased. Offensive and defensive behaviors showed attenuation. Current results corroborate previous findings with respect to 5-HT1A receptor involvement in murine agonistic behavior and anxiety. Data also connote that the behavioral specificity of 5-HT1A ligands should be interpreted in terms of response competition rather than solely concomitant sedation.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1994

Mutagenic activity of 3 industrial chemicals in a battery of in vitro and in vivo tests.

3 chemicals were selected for mutagenicity testing from a priority list, based on production volume and available mutagenicity data. Propargyl alcohol (PA), 2-nitroaniline (2NA), and 5-methyl-1H-benzo-triazole (MBT) were selected for testing using the approach recommended in the Health Protection Branch Genotoxicity Guidelines. The battery of tests included the Salmonella/mammalian microsome mutation assay, the in vitro chromosomal aberration assay, and the bone-marrow micronucleus assay. The results indicate that 2 of the 3 chemicals, PA and 2NA, were clastogenic in vitro. Both PA and 2NA induced chromosomal aberrations in CHO cells in vitro with and without metabolic activation, while none induced reverse mutations detectable with the Salmonella/mammalian microsome assay. Because PA and 2NA were found to be in vitro clastogens, they also were tested in the mouse bone-marrow micronucleus assay. 2NA induced a small increase in micronuclei in males but not females. PA did not induce an increase in micronuclei.

1-Propanol↗
PubMed1994

Vibrindole A, a metabolite of the marine bacterium, Vibrio parahaemolyticus, isolated from the toxic mucus of the boxfish Ostracion cubicus.

The EtOAc extract of the whole culture medium of Vibrio parahaemolyticus, which inhabits the toxic mucus of the box fish Ostracion cubicus, afforded a new indole-derived natural product, vibrindole A [1], along with some known cyclic dipeptides and indoles. The structure of 1 was determined by analysis of its physicochemical characteristics.

Animals↗
PubMed1994

Effects of total hepatectomy: studies in a porcine model.

The effects of total hepatectomy in a porcine model were studied. A portacaval shunt was constructed prior to hepatectomy, and the excised segment of inferior vena cava was replaced with a Dacron graft as soon as the liver had been removed. While the vena cava was clamped, venous return from the lower body to the heart was maintained using an extracorporeal veno-venous bypass system. The results of the study revealed that surprisingly few haemodynamic, biochemical or coagulation disturbances occur within the first 5 h following total hepatectomy in the pig, an animal with remarkably close anatomical and physiological similarities to man. In the anhepatic period which follows total hepatectomy during clinical liver transplantation, the situation is more complex, because pre-existing liver disease and portal hypertension, as well as major blood loss, often provide other reasons for metabolic and haemodynamic instability and coagulation disorders. The possible relevance of the findings in this large animal model to events that occur following total hepatectomy in the clinical situation is discussed.

Alkaline Phosphatase↗
PubMed1994

A comparison of flushing solutions for liver procurement using an isolated perfused porcine model.

There is no agreement on the best technique of in situ flushing of livers prior to storage. In order to study this, porcine livers were stored in the University of Wisconsin (UW) solution for 18 h and then assessed using an isolated perfused porcine model. Livers flushed in situ with UW solution were compared to livers flushed with a non-preservation solution (Hartmann's solution). No statistically significant differences could be found in bile production (18.7 +/- 4.4 vs 17.9 +/- 3.8mL/1000 g per 2 h), aspartate amino-transferase (AST) levels in the perfusate after 2 h of isolated perfusion (687 +/- 101 vs 724 +/- 114 U/L), potassium levels in the perfusate after 2 h on the circuit (5.4 +/- 1.5 vs 5.5 +/- 2.3 mmol/L), weight gain (15.2 +/- 3.7 vs 17.1 +/- 4.0%) or platelet sequestration (41.6 +/- 11.7 vs 37.4 +/- 9.8%) between livers flushed with UW solution as opposed to those flushed with Hartmann's solution, respectively. Of overriding importance was the solution in which the liver was stored, reconfirming the superiority of UW solution over an extracellular solution for preservation. If extrapolated to the clinical situation, these findings would have substantial cost-saving implications.

Adenosine↗
PubMed1994

Exercise and pregnancy: a review.

The effects of pregnancy on the maternal cardiorespiratory system include increases in oxygen consumption, cardiac output, heart rate, stroke volume, and plasma volume. The increase in oxygen reserve seen in early pregnancy is reduced later, suggesting that maternal exercise may present a greater physiologic stress in the third trimester. Evidence suggests that weight-bearing exercise produces a greater decrease in oxygen reserve than nonweight-bearing exercise. Furthermore, to maintain a heart rate below 140 beats per minute during pregnancy, the intensity of weight-bearing exercise must be reduced. Nonweight-bearing, water-based exercise results in smaller fetal heart rate changes and a lower maternal heart rate than the same exercise performed on land. Exercising in the supine position in late pregnancy has raised concerns because cardiac output in the supine position is lower than in the lateral position at rest, presumably because the gravid uterus partially obstructs the inferior vena cava. Sustained exercise produces a training effect on the mother, although reported associations between this effect and the experience of labor are not consistent. Short-term changes in fetal heart rate provide circumstantial evidence that physical activity can influence the fetus. Acute effects of exercise that can potentially affect the fetus include hyperthermia, changes in uteroplacental flow, reduced levels of maternal glucose, and increased uterine contractions. Moderate to high levels of sustained maternal exercise have been associated with reduced birthweight. Much research remains to be done on the effects of specific exercise regimens during pregnancy, the effects on previously sedentary women, and the long-term health consequences to the offspring of women who perform vigorous exercise during pregnancy.

Birth Weight↗
PubMed1994

Community psychiatric nurse teams: intensive support versus generic care.

BACKGROUND: This study evaluated whether a community psychiatric nurse (CPN) team providing a comprehensive aftercare service, using a case management approach, improves psychopathology and social functioning of the long-term mentally ill, and reduces hospital use compared with a generic CPN team. METHOD: Patients suffering from severe and persistent mental health problems were randomised to intensive aftercare or generic care after referral to the CPN manager. Each group contained 41 patients who were assessed at baseline and at 6, 12 and 18 months by an independent research psychologist. Outcome measures included the GAS, PSE, SAS, patient and relatives' satisfaction, number of admissions, and length of stay. RESULTS: No difference between the groups was found on any of the outcome measures, despite the much higher number of contacts of the intensive (n = 52) versus generic CPNs (n = 13) and the much greater range of interventions. CONCLUSIONS: Intensive aftercare for people with persistent mental health problems was not found to be of greater benefit than generic CPN care. Many factors need to be considered for aftercare to be effective, including community resources, process of care, and staff training.

Activities of Daily Living↗
PubMed1994

Determinants of hospital-based substance abuse treatment programs.

Experts agree that treatment is the best solution to substance abuse problems. As the societywide problem of drug and alcohol dependence increases, so does the need for treatment programs. Research has shown that many hospitals have entered into the substance abuse treatment program business because a need for quality programs exists and because an alcohol and a substance abuse treatment product line has the potential for increasing sagging revenues. This article addresses the question of what types of hospitals are likely to engage in providing inpatient and/or outpatient treatment programs. The results indicate that organizational size (measured by the number of beds) is the best predictor of treatment service provision for both inpatient and outpatient settings, with larger hospitals being more likely to provide substance abuse programs. A need for additional chemical dependency treatment programs does not appear to be the primary motivating factor for hospitals developing this service. Rather, it seems hospitals provide these programs for other reasons--as part of providing a full array of services, as an average toward achieving organizational goals, as a means of sustaining a competitive advantage, or as a strategy for maintaining the same level of service as the competition.

Data Collection↗
PubMed1993

Outcome and prognostic factors in soft tissue sarcoma in the adult.

PURPOSE: To evaluate the outcome, patterns of failure and prognostic factors in this rare disease in adult patients treated at a single institution in the modern era. METHODS AND MATERIALS: The records of all patients (389 cases) with soft tissue sarcoma in the extremities, torso (excluding retroperitoneum), and head and neck managed between 1980 and 1988 were reviewed. A curative (radical) approach was used in 321 patients of whom 10% were recurrent lesions. The local management consisted of surgery alone in 54 cases, surgery and radiotherapy in 250 and radiotherapy alone in 17. Adjuvant chemotherapy was used as a policy for high grade lesions in the initial five years of the study (98 cases), but was omitted subsequently. RESULTS: Extremity lesions fared more favourably compared to head and neck and torso lesions (p = 0.02) with respect to survival. Extremity and torso lesions had significantly better local control (p < 0.0001) than in the head and neck where local failure was a common cause of death. A multiple Cox regression analysis revealed that resection margins, local extension of tumor, age at diagnosis, and grade correlated with local relapse and distant relapse was also associated with local extension, high grade and in addition, large lesions. Size appeared especially predictive for distant failure, the most common cause of death. Distant failure was not influenced by the use of adjuvant chemotherapy. Patients treated for recurrence in this series had significantly worse survival due to increased distant failure despite similar local control to primary cases. CONCLUSION: This series highlights the overall problem of distant failure in this disease. It also reaffirms the importance of obtaining local control both in the head and neck, where uncontrolled local disease is the major cause of death, and in general since local relapse appears to increase the risk of distant failure. It appears that the current staging systems should be reviewed in the light of the apparent effect of different prognostic factors.

Actuarial Analysis↗
PubMed1993

Homogeneous antigen receptor beta-chain genes in cloned CD4- CD8- alpha beta T suppressor cells.

The rearrangements of beta-chain genes of the T cell Ag receptor were examined in 12 CD4- CD8- alpha beta + T cell lines derived from the spleen or thymus of neonatal or adult BALB/c mice. Eleven of the lines were cloned and established from six independent cloning procedures from different mice. Five cloned lines used V beta 9, four cloned lines used V beta 15, and two cloned lines used V beta 7. Nucleotide sequencing of the beta-chain genes showed that clones that used a given V beta were identically rearranged even when they were derived from independent cloning procedures. In the case of V beta 7 and V beta 15 all nucleotides in the V-D-J joining region were in the germ line configuration without N region additions. Rearrangements of the V beta 7, V beta 9, and V beta 15 genes were functional. Each V beta 15 clone also had a homogeneous rearrangement of the V beta 13 gene, which was nonfunctional. The predicted amino acid sequence of the joining regions of the V beta 7, V beta 9, and V beta 15 rearrangements showed homology in four of seven amino acids in the peptide contact region.

Animals↗
PubMed1993

Usage of T cell receptor beta-chain variable gene is highly restricted at the site of inflammation in murine autoimmune uveitis.

Improved molecular methods allow identification of the specific autoaggressive T cells involved in autoimmune inflammations. In this study of interphotoreceptor retinoid-binding protein-induced uveitis, TCR V beta usage was studied using RNA-polymerase chain reaction amplification of transcripts derived directly from ocular tissues and from T cell lines obtained from the spleen. Specific V beta 5' primers from the major murine TCR V beta families were coupled with a common 3' primer from the V beta C region. Amplification of rearranged TCR V beta-D beta-J beta-C beta sequences was confirmed by Southern blot analysis. In ocular tissue from sensitized mice, TCR V beta expression was limited mainly to one to three V beta families, with predominant expression of V beta 2, V beta 12, and V beta 15. In most animals there was similar, albeit limited, TCR gene usage in both the recognition of autoantigen in uveitogenic T cell lines and at the site of inflammation in the eye. Identification of a limited TCR V beta repertoire in Ag-reactive T cell lines correlated with TCR usage at the target site of autoimmune expression. The gene products of the restricted TCR V beta rearrangements found in lesions and in the cell lines may serve as the target for selective immunotherapy.

Animals↗
PubMed1993

Effects of (-)-pindolol and SDZ 216-525 on social and agonistic behavior in mice.

In view of conflicting results reported for 5-HT1A receptor involvement in murine social conflict, this study examined the effect of two compounds, SDZ 216-525 and (-)-pindolol, on agonistic and social behavior in male mice. In a resident-intruder paradigm, (-)-pindolol (1.0-20.0 mg/kg), a beta-adrenergic 5-HT1A/1B antagonist, significantly attenuated all agonistic behaviors across the dose range employed. Social behaviors showed significant decreases, while nonsocial cage exploration showed significant increases at all doses. Defensive evade was significantly attenuated at 20.0 mg/kg. SDZ 216-525 (0.025-1.0 mg/kg), a selective 5-HT1A antagonist, significantly attenuated offensive posturing and bite-attacks at 1.0 mg/kg, and all offensive behaviors nonsignificantly at the smaller doses tested. Rearing was significantly attenuated at 1.0 mg/kg, while cage exploration increased at this dose. Defensive and social behaviors remained largely unchanged. These results show that both compounds tested produced significant reductions in offensive behavior, with concomitant changes in defensive, social, and nonsocial behaviors. Results are discussed in relation to SDZ 216-525 and (-)-pindolol potential for the control of anxiety and agonistic behavior.

Agonistic Behavior↗
PubMed1993

Effects of pindobind 5-hydroxytryptamine1A (5-HT1A), a novel and potent 5-HT1A antagonist, on social and agonistic behaviour in male albino mice.

In view of inconsistent results reported for 5-hydroxytryptamine1A (5-HT1A) receptor involvement in murine social conflict, this study examined the effects of N1-(bromoacetyl)-N8-[3-(4-indolyloxy)-2- hydroxypropyl]-(Z)-1,8-diamino-p-menthane (pindobind) 5-HT1A, a novel 5-HT1A antagonist, on agonistic and social behaviour in mice. Employing a resident-intruder paradigm, administration of pindobind 5-HT1A (0.5-10 mg/kg) to resident animals produced a reduction in offensive sideways and chasing behaviour. Defensive postures were unchanged except for evasion, which was reduced. Within social behaviour, nonspecific social behaviour and following behaviour were reduced while stretch/attend behaviour was enhanced. Nonsocial behavioural changes included an increase in resident cage exploration and rearing. Intruder data indicated no significant change in offensive behaviours, an attenuation of defensive sideways posturing and evasion, decreases in attend behaviour, and increases in cage exploration, rearing, and digging. Results are discussed in relation to the effects of 5-HT1A receptor (ant)agonism on murine offensive behaviour.

Agonistic Behavior↗
PubMed1993

Factors associated with severe intracranial hypertension in candidates for emergency liver transplantation.

Cerebral edema is the leading cause of death in patients with fulminant hepatic failure (FHF). Emergency OLT is often a life-saving therapy for FHF but severe cerebral edema is a contraindication to transplantation. We attempted to identify clinical and biochemical factors associated with the development of severe intracranial hypertension in FHF. Fever, psychomotor agitation, and arterial hypertension were more frequently observed preceding episodes of severe intracranial hypertension, and more than 50% of FHF patients with uncontrolled intracranial hypertension sustained severe brain injury in our series. These observations suggest that vigorous treatment of fever, arterial hypertension, and agitation are important aspects of the intensive care management of FHF patients to maintain their OLT candidacy.

Adult↗