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Biomedical subjects

A Nicholson

Publications and source records attributed to A Nicholson.

At least 73 records · Page 4Linked to original sources
PubMed1992

Neuromuscular and cardiovascular effects of atracurium in isoflurane-anesthetized chickens.

Atracurium besylate, a nondepolarizing neuromuscular blocking agent, was administered to 24 isoflurane-anesthetized domestic chickens. Birds were randomly assigned to 4 groups, and atracurium was administered at dosage of 0.15, 0.25, 0.35 or 0.45 mg/kg of body weight. The time of onset of twitch depression, the amount of maximal twitch depression, and the duration of muscular relaxation were recorded. After return to control twitch height, atracurium was further administered to achieve > 75% twitch depression. When twitch depression reached 75% during noninduced recovery, 0.5 mg of edrophonium/kg was administered to reverse the muscle relaxation. Throughout the experimental period, cardiovascular, arterial blood gas, and acid-base variables were monitored. The effective dosage of atracurium to result in 95% twitch depression in 50% of birds, (ED95/50) was calculated, using probit analysis, to be 0.25 mg/kg, whereas the ED95/95, the dosage of atracurium to result in 95% twitch depression in 95% of birds, was calculated by probit analysis to be 0.46 mg/kg. The total duration of action at dosage of 0.25 mg/kg was 34.5 +/- 5.8 minutes; at the highest dosage (0.45 mg/kg), total duration increased to 47.8 +/- 10.3 minutes. The return to control twitch height was greatly hastened by administration of edrophonium. Small, but statistically significant changes in heart rate and systolic blood pressure, were associated with administration of atracurium and edrophonium. These changes would not be clinically relevant. In this study, atracurium was found to be safe and reliable for induction of muscle relaxation in isoflurane-anesthetized chickens.

Anesthesia Recovery Period↗
PubMed1990

Developmental delay in congenital myotonic dystrophy after neonatal intensive care.

Six infants with congenital myotonic dystrophy survived after neonatal intensive care. In later childhood they were assessed by the Griffiths Mental Development Scales: five children were functioning in the mildly handicapped to borderline range of development (DQ 64.0 to 79.0) and the remaining child was severely delayed in development (DQ 33.0). The five children with higher DQ values had a history of ventilatory support of 30 days or less after birth. By contrast, the remaining child with the lowest DQ value had been ventilated for 43 days. This study provides further evidence that prolonged ventilation after birth has prognostic significance in identifying severely affected cases with congenital myotonic dystrophy.

Child, Preschool↗
PubMed1989

Fat malassimilation in three cats.

Three cats were thin despite eating well. Steatorrhoea was confirmed in each by 72-hour fat assimilation tests. Fat digestibility in all 3 increased twofold when the diet was supplemented with pancreatic enzymes, suggesting the possibility of exocrine pancreatic insufficiency. However, examination of stained faecal smears gave evidence of both maldigestion and malabsorption of fat, without maldigestion of starch, and only one case had indications of protein maldigestion. In the latter cat, fat digestibility normalised with pancreatic enzyme supplementation and exocrine pancreatic insufficiency was considered likely. However, at post-mortem examination enteropathy and pancreatitis, but not exocrine pancreatic insufficiency, were found. The cause of fat malassimilation in these cats was unknown. The evaluation of malassimilation in cats is difficult because investigative tests used in other species are either unsuitable or have not been evaluated in cats.

Animals↗
PubMed1988

The effect of L-glutamic acid on airway function and reactivity in the rabbit.

The ingestion of monosodium glutamate in sensitive individuals has been reported to cause severe asthma. We therefore studied the effects of L-glu on airway function and histamine (H) responsiveness in the rabbit. Histamine dose response curves (HDR's) were performed by measuring total lung resistance (RL) after inhalation of saline and increasing concentrations of H (1-30 mg/ml). The concentration of H producing a 20% increase in RL (PC20H) was obtained by interpolation. To assess the effects of L-glu, 8 rabbits were infused with L-glu (0.2 g/kg/hr) or saline in random order (14 days apart) for 4 hours followed by an HDRC. To look at possible late effects, a repeat HDRC was also performed in 6 rabbits 12 hours after completion of the L-glu infusion. In order to see whether rabbits rendered hyperresponsive responded to L-glu, the above protocol was performed in 7 rabbits following the inhalation of 3 micrograms of the activated complement fragment C5a des Arg. The L-glu infusions increased the plasma levels approx. ten-fold (mean +/- SEM 0.119 +/- 0.012 base-line, 1.272 +/- 0.061 mmol/l post infusion). L-glu did not increase the PC20H or baseline RL in either the normal rabbits at 4 or 12 hours or in the C5a des Arg treated rabbits at 4 hours. It is concluded that L-glu does not cause bronchoconstriction or an increase in airway responsiveness to H in the rabbit.

Administration, Inhalation↗
PubMed1988

Deferoxamine infusion does not inhibit bleomycin-induced lung damage in the rat.

It has been proposed that the pneumonitis and subsequent lung fibrosis induced by bleomycin occurs when bleomycin is complexed with ferrous iron and oxygen. In order to see whether chelation of free iron reduced tissue damage induced by intratracheal bleomycin, deferoxamine (DFO) was administered by continuous subcutaneous infusion to overcome its rapid renal excretion. Thirty-three rats received DFO and 30 rats received an equivalent volume of saline by 7-day infusion pumps. Three days after commencement of infusion, half of each group received intratracheal bleomycin, the remainder received intratracheal saline. Three weeks after intratracheal injection, the rats were killed and their lungs were removed for histologic and morphometric assessment and collagen estimation. When compared with animals given intratracheal saline, both bleomycin-treated groups had significant evidence of lung toxicity, but DFO was not protective. Similarly, DFO infusion did not reduce the elevation in collagen concentration (bleomycin/saline, 49 +/- 3.6; bleomycin/DFO, 49.8 +/- 4.1; saline/saline, 39.6 +/- 3.9; saline/DFO, 43.4 +/- 3.8 mg.g-1 wet lung weight) or total lung collagen (bleomycin/saline, 29.9 +/- 6.3; bleomycin/DFO, 33.7 +/- 1.8; saline/saline, 15.5 +/- 2.2; saline/DFO, 17.8 +/- 1.9 mg.left lung-1) induced by bleomycin. This lack of effect was not due to iron contamination of the DFO in the pump or to loss of chelation capacity of DFO, at least for as long as 6 days after pump implantation. No DFO was detected in homogenized lung tissue (limits of detection of assay was 8 x 10(-5) M).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Failure of systemic N-acetyl cysteine to protect the rat lung against bleomycin toxicity.

In order to see whether systemically administered N-acetyl cysteine (NAC) could protect the lung from bleomycin lung injury, 24 rats were given a constant subcutaneous infusion of NAC (mean 195 mg.kg-1.day-1) for 7 days while 23 rats were given a similar volume of saline. Two days after the start of infusion, half of each group received an endotracheal injection of bleomycin and the other half received a similar volume of saline. All animals were killed 7 days after intratracheal injection and their lungs were prepared for wet-weight to dry-weight ratio (W:D) and morphometric assessment of histological changes. In animals given intratracheal saline, NAC infusion had no effect on weight gain, W:D or morphometry compared to those animals given saline infusions. However, all bleomycin-treated animals had obvious evidence of lung damage. Compared to either group of animals treated with intratracheal saline, the bleomycin-treated groups gained less weight (p less than 0.001), had a higher W:D (p less than 0.001) and an increase in the volume densities of alveolar and duct walls (p less than 0.001), intra-alveolar cells (p less than 0.05) and consolidation (p less than 0.001). There were no significant differences between the two bleomycin-treated groups in any parameter measured. It is concluded that administration of NAC by a constant subcutaneous infusion was not protective against bleomycin lung injury.

Acetylcysteine↗
PubMed1986

Dr. Copeland on cardiac transplantation. Interview by Monica Kalker.

The following interview is an exchange between Jack Copeland, M.D., Robert Emery, M.D., and Anne Nicholson, R.N., members of the heart transplant team at the University of Arizona Medical Center in Tucson, Arizona. Dr. Copeland currently is the chief cardiac surgeon as well as professor and chief of Cardiovascular and Thoracic Surgery. Dr. Emery is an associate professor in the division of cardiothoracic surgery. Ms. Nicholson is a cardiac transplant coordinator for the Center. The University of Arizona's Heart Transplant program has proven itself in terms of actuarial survival, innovative approaches to recipients, surgical techniques, and with the maintenance of relatively short hospital stays and low costs to the patient.

Arizona↗
PubMed1984

Sarcocystis encephalitis in a cockatiel.

A sporozoan organism was considered to be the causative agent of central nervous system disease in a cockatiel. The ultrastructural characteristics were typical of the coccidian group Apicomplexa, and the fact that organisms were free within the cytoplasm of infected cells and not within a vacuole, indicated they were Sarcocystis. Light and electron microscopic evaluation of brain tissue demonstrated protozoal organisms associated with areas of necrosis. Differential diagnosis of central nervous system disease in pet birds should include protozoal encephalitis.

Animals↗
PubMed1982

Randomized comparative trial of a ward discussion group.

A randomized controlled study of 38 catchment unit psychiatric in-patients in a discussion group showed no significant additional benefit compared with 36 in-patients in an activity group. Symptom change scored by three rating groups agreed closely, average r = +0.64. Patients treated with ECT showed 2.6 times as much reduction in morbidity as those not so treated, but there was still no appreciable difference between discussion and activity groups when this was allowed for. Other treatment factors and the Hawthorne effect appeared to obscure any effect due to group therapy.

Adult↗
PubMed1979

Host defense against Neisseria meningitidis requires a complement-dependent bactericidal activity.

Some individuals, with severe or recurrent infection with Neisseria species, have been identified as lacking a component in the terminal attack sequence of complement (complement components 5 to 9). The relevance of the terminal attack sequence to various phases of host defense was tested with the use of the C-11 strain of meningococci and human serum genetically deficient in complement component 8 (C8-D). The C8-D serum was comparable to normal serum in supporting ingestion and intracellular killing by leukocytes but was not bactericidal in the fluid phase unless reconstituted with C8. Thus, serum complement-dependent bactericidal activity may be especially critical for the host's defense against invasive Neisseria species.

Blood Bactericidal Activity↗
PubMed1979

Salivary tumours--experience over thirty years.

A clinicopathological survey of tumours of salivary glands seen in a special surgical clinic at the Christie Hospital and Holt Radium Institute is reported. Nine hundred and seventy-seven benign and malignant tumours have been seen within the past 30 years. The results of treatment are included with particular attention to those of the parotid glands which present the greatest therapeutic problem. The approach to surgical treatment of pleomorphic adenomas is described in detail and guidelines offered as to the procedure that should be used based on full exploration and assessment of each tumour. The need for adjuvant irradiation depends on the standard of surgery that is done. The relationship between carcinomas and benign adenomas is discussed and the need for surgery in all cases is stressed in order to make a definite histological diagnosis in view of the wide range of pathological abnormality encountered.

Adenolymphoma↗
PubMed1979

The spectrum of Bacillus bacteremias in heroin addicts.

Bacillus bacteremias occurred in two heroin addicts. The first patient had one day of fever and chills after intravenous heroin use. Persistent cereus bacteremia consistent with endocarditis was documented and responded to four weeks of antibiotic therapy. The second patient had non-cereus Bacillus species isolated from blood cultures three times over eight days, each time after renewed heroin use. The patient remained well, and the bacteremias cleared spontaneously. Because Bacillus species frequently contaminate heroin injection materials and because the Bacillus bacteremias were temporally associated with intravenous heroin use, Bacillus bacteremias in both patients probably eventuated from heroin abuse. These cases, in conjunction with two previously reported cases of Bacillus endocarditis in heroin addicts, suggest that heroin addicts are at risk for developing Bacillus bacteremias, which may vary in severity from endocarditis to benign transient bacteremias.

Bacillus↗
PubMed1979

Lymphocytes forming stable E-rosettes in acute and chronic hepatitis.

Lymphocytes forming E-rosettes with sheep erythrocytes which do not disintegrate at 37 degrees C have been demonstrated in increased numbers in peripheral blood of patients with acute type B hepatitis (6--20% of lymphocytes) and with HBsAg negative active chronic hepatitis (9--28% of lymphocytes). They were not increased in patients with HBsAg positive active chronic hepatitis. Such lymphocytes were adherent to nylon wool and a large proportion of them had FcIgG receptors (21--69%). These are properties of a subpopulation of T lymphocytes having suppressor function.

Adult↗