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Biomedical subjects

C McDonald

Publications and source records attributed to C McDonald.

At least 109 records · Page 6Linked to original sources
PubMed1989

A three-dimensional analysis of angular momentum in the hammer throw.

Eight hammer throwers were studied using three-dimensional cinematography. The local term of angular momentum of each thrower (HTL) followed a wide conical path, while the remote term (HTR) and the hammer angular momentum (HH) followed much narrower conical paths. HT, the sum of HTL and HTR, followed a conical path similar to that of HTL, although with smaller amplitude. HH was half of a cycle out of phase with HT. It was also larger but followed a narrower conical path. As a result, the conical paths of HH and HT counteracted each other, and HS, the total angular momentum vector of the thrower-hammer system, had little conical motion. The paths of the angular momentum vectors, the trunk tilt, and the height of the hammer plane relative to the system center of mass were interrelated. Some throwers kept the hammer plane high and the trunk tilting back in all the turns; other throwers kept the hammer plane low and the trunk tilting forward in the early turns, but the hammer plane rose in their late turns and the trunk tilted back. Two theories were proposed to explain why the athletes who had forward trunk tilt in the early turns tilted backward in the final part of the throw.

Biomechanical Phenomena↗
PubMed1988

Enprofylline in chronic asthma.

A double-blind crossover study has been performed in 14 patients with moderately severe chronic asthma to compare the bronchodilator efficacy of two dosage regimens of intravenous enprofylline (high dose = 2 mg/kg bolus and 1 mg/kg/hour infusion; low dose = 1 mg/kg bolus and 500 micrograms/kg/hour infusion) with aminophylline (5 mg/kg/bolus and 500 micrograms/kg/hour infusion) and placebo. The bolus injections were given over 20 minutes and infusion over 160 minutes. Twelve subjects completed the study. High dose enprofylline was more effective than aminophylline in increasing PEF (P = 0.008) and FEV1 (P = 0.004). Low dose enprofylline and aminophylline were of similar efficacy. Side-effects, notably headaches and nausea, were more common with enprofylline; three out of 14 subjects receiving the high dose regimen developed severe nausea. The plasma enprofylline levels achieved with the high dose regimen were greater than anticipated. Further studies are required in acute severe asthma to clarify the therapeutic role of intravenous enprofylline and the most appropriate dosage regimen.

Adult↗
PubMed1988

Evaluation of the combination inhaler of salbutamol and beclomethasone dipropionate in the management of asthma.

An open parallel study lasting 24 weeks was performed in 39 asthmatics to evaluate patient compliance and the clinical effects of regular inhalations of beclomethasone dipropionate and salbutamol used simultaneously from a combination inhaler with regular inhalations of salbutamol and beclomethasone dipropionate used sequentially from separate inhalers. Total daily doses in the two groups were 800 micrograms salbutamol and 400 micrograms beclomethasone dipropionate. There were no differences between the two treatment groups with respect to clinic pulmonary function tests (FEV1, FVC), daily PEF measurements, symptom scores, use of symptomatic bronchodilator therapy, requirements for extra medication and patients' and physician's assessment of treatment. At 12 weeks, the physician assessed significantly more patients to have better symptom control on the combination inhaler than on separate inhalers. Patient compliance was high in both treatment groups which may have been due to the close supervision of the clinical study.

Administration, Inhalation↗
PubMed1988

Personality trait characteristics in relation to neuropsychological dysfunction in schizophrenia and depression.

Knowledge of the personality trait and psychopathology variables that differentiate neuropsychologically impaired and nonimpaired psychiatric patients has been limited relative to the study of higher cortical functions. This study reports findings from the Millon Clinical Multiaxial Inventory (MCMI) developed by Millon (1982) in a sample of hospitalized schizophrenics and depressives who also received the Luria-Nebraska Neuropsychological Battery. The principal findings indicate that neuropsychological dysfunction may be related to substance abuse, including its underlying personality dimensions, in schizophrenia, but only modest support is indicated for the construct of negative symptoms in schizophrenics with neuropsychological dysfunction. Further, the findings do not support the view that psychosis is a characteristic feature of depressives with impaired neuropsychological performance.

Adult↗
PubMed1988

Differential patterns of neuropsychological deficit in psychiatric disorders.

This report investigated differential cerebral impairment on the Luria-Nebraska Neuropsychological Battery in schizophrenia, schizoaffective, and depressive disorders (N = 106). Results indicated impaired tactile-stereognostic processing in schizoaffective and depressive disorder patients and verbal memory deficits in the schizophrenic and schizoaffective disorder patients. These findings question the specificity of functional neuropsychological deficit areas in schizophrenia and depression.

Adult↗
PubMed1987

Gastric emptying of solid food in patients with gastroesophageal reflux.

While delayed gastric emptying of solid food has been reported in patients with symptoms of gastroesophageal reflux, the study populations were not defined by 24-h intraesophageal pH monitoring. Moreover, the influence that the gastric emptying rate may have on patterns of reflux during the day or night, as well as on esophagitis, is not known. In this study, we compared the gastric emptying rate of solid food (in vivo intracellular labeled chicken liver) observed in asymptomatic control volunteers (n = 15) with that of symptomatic patients with an abnormal 24-h pH record who had either the presence (n = 22) or absence (n = 11) of endoscopic esophagitis. We found no significant difference in the gastric emptying rate between the asymptomatic control volunteers and the symptomatic patients with and without esophagitis. Moreover, there was no significant correlation between the gastric emptying rate and the degree of daytime or nighttime distal esophageal acid exposure found during 24-h intraesophageal pH monitoring. Only 6% of the symptomatic patients had a gastric emptying rate that exceeded the mean value plus 2 SD of that found in the asymptomatic control volunteers. We believe these support a de-emphasis of the role that delayed gastric emptying of solid food may play in the pathophysiology of gastroesophageal reflux in most patients.

Adult↗
PubMed1987

Solubilities and intrinsic dissolution rates of sulphamethoxazole and trimethoprim.

The influence of pH on the dissolution rates and solubilities of sulphamethoxazole and trimethoprim have been examined. Sulphamethoxazole was evaluated in buffers of ionic strength 0.5 mol dm-3 over the pH range 0.45-7.8 and at 25, 32 and 37 degrees C. The minimum solubility of sulphamethoxazole was 28.1 mg/100 mL at pH 3.22 and 25 degrees C. Solubilities increased significantly with both increased and decreased pH. Intrinsic dissolution rates demonstrated a linear relationship with the solubility data. Trimethoprim solubility was both buffer- and pH-dependent. In both water and hydrochloric acid solution at 32 degrees C the solubility of trimethoprim increased from 50 mg/100 mL in water at pH 8.54 to a maximum of 1550 mg/100 mL at pH 5.5. This maximum solubility was in excess of that predicted theoretically and may be due to supersaturation. Below pH 2 the solubility of protonated trimethoprim diminished from 1125 mg/100 mL with decreasing pH. This was due to the common ion effect. Intrinsic dissolution rates increased as pH was decreased with hydrochloric acid from 6.00 to 1.78, but decreased at pH 1.48 due to the common ion effect. Dissolution profiles of trimethoprim showed complex patterns dependent upon pH. The profile was zero-order at pH 6.00 and became distinctly stepwise at pH 5.5, this effect becoming less pronounced at lower pH values. This was reconciled in terms of the rate of formation of trimethoprim hydrochloride on the surface of the disc and the differing dissolution rates of this species and trimethoprim. A simple relationship between solubility and dissolution rate was not observed.

Hydrogen-Ion Concentration↗
PubMed1986

The early course of schizophrenic thought disorder.

The current investigation studied the early course of positive thought disorder and its relationship to other aspects of schizophrenic outcome. Forty-eight schizophrenics diagnosed using the Research Diagnostic Criteria (RDC), 51 psychotic nonschizophrenics, and 67 nonpsychotic patients were studied at index hospitalization and at a 1.5-year followup. Most thought-disordered schizophrenics and other psychotic patients showed some reduction in thought pathology between index hospitalization and followup (p less than .02). A larger percentage of schizophrenics than other psychotic and nonpsychotic showed thought disorder at the acute phase and at followup assessment (p less than .05), although only a subgroup of 27 percent of the schizophrenics showed severe thought disorder at followup. At followup, severely thought-disordered schizophrenics showed residual signs of psychosis and poor functioning in other areas. Positive thought disorder in schizophrenics at followup most often occurred within the context of an unremitted illness and was less frequently due to a new, acute episode of disturbance. Continuously thought-disordered schizophrenics exhibited more severe impairments in life adjustment at 1.5-year followup than did episodic or nonthought-disordered schizophrenics (p less than .02). The results suggest that severe thought disorder is a persistent characteristic in a subgroup of early schizophrenics.

Acute Disease↗
PubMed1986

Stability of aqueous solutions of amoxicillin sodium in the frozen and liquid states.

The stability of aqueous admixtures of amoxicillin sodium in both the liquid and frozen (solid) states was studied. Admixtures of amoxicillin sodium were prepared in sterile water for injection to a theoretical concentration of 10 mg/mL. For each experimental run, 2-mL aliquots of the admixture were placed in stoppered glass volumetric flasks and stored at temperatures ranging from 19.5 degrees C to -30 degrees C; 16 flasks were stored at each temperature. After equilibration for approximately 20 minutes, duplicate flasks at each temperature were removed from storage conditions for time-zero assay. Subsequently, duplicate flasks were assayed at various times, depending on the storage temperature, for up to 13 days or until more than 80% of the drug had degraded. All samples were assayed at least in duplicate using high-performance liquid chromatography. When amoxicillin solutions were in the liquid state (at temperatures between 19.5 and 0 degrees C), the time required for the amoxicillin concentration to decrease to 90% of its initial value (t90) increased as temperature decreased. However, between 0 degree C and -7 degrees C, the t90 of frozen solutions decreased from two days to 1.08 hours. As temperature declined further, the rate of degradation decreased until the solution was completely frozen; at -30 degrees C, the t90 had increased to 13 days. Amoxicillin sodium is unstable in aqueous solutions stored between 0 degrees C and -20 degrees C. If admixtures of this drug are to be frozen for later use, the storage temperature should be below -30 degrees C.

Amoxicillin↗
PubMed1985

Immunochemical testing for faecal occult blood in patients with colorectal cancer.

Eighty-six stool specimens collected from 36 patients with colorectal cancer were tested for occult blood by chemical and immunochemical methods. There was no dietary restriction. Positive results were obtained in 94% of patients by the immunochemical method when the presence of any positive immunochemical test was taken as a positive result. If greater than 1 mg of haemoglobin per gram of faeces was regarded as positive result, then 75% of patients would have been diagnosed as having occult blood in the stool by means of the immunochemical method. Positivity rates for Hemoccult II and rehydrated Hemoccult II were 53% and 81%, respectively.

Colonic Neoplasms↗
PubMed1985

Sequence organisation of rat seminal vesicle F gene: location of transcriptional start point and sequence comparison with six other androgen-regulated genes.

Seminal vesicle F gene, encoding an androgen-regulated serine-rich structural protein of the rat copulatory plug, has been sequenced together with 5' and 3' flanking regions. The intron/exon arrangement of the gene deduced from restriction maps was confirmed. The major and possible minor transcriptional start points were located by primer extension analysis and S1 nuclease mapping. A published nucleotide sequence for seminal vesicle S gene which also encodes an androgen-regulated protein of the copulatory plug has been extended to allow comparison of F and S genes. The considerable sequence homology between the two genes confirms their evolutionary relatedness. Homology is especially high in their promoter regions and their transcriptional start points are identical. They share several regions of dyad symmetry including one just upstream of the promoter. The upstream regions of F and S genes were compared with those of five other androgen-responsive rodent genes in an attempt to identify common sequence motifs that might be involved in hormonal regulation of gene expression.

Animals↗
PubMed1985

A diffusable factor in Scottish coagulation factor concentrates can inhibit lymphocyte transformation in vitro.

Coagulation factor VIII and IX concentrates produced in Scotland inhibited human lymphocyte transformation induced by lectins or the recall antigen, purified protein derivative of tuberculin (PPD). Although concanavalin A could bind factor VIII directly and PHA could bind factor IX directly, most of the inhibition was not due to direct clotting factor - lectin interaction nor to simple toxicity. Most of the inhibitory activity from both clotting factors could be removed by dialysis. A similar degree of inhibition was observed when the buffers used to prepare the concentrates were substituted for the concentrates themselves, and a comparable concentration of sodium citrate was also found to be inhibitory. Coagulation factor VIII partially purified by gel filtration was not found to have an appreciable effect on lymphocyte transformation in vitro.

Cells, Cultured↗
PubMed1985

Diet and drinking habits in relation to the development of alcoholic pancreatitis.

To determine whether increased intakes of fat and protein or particular drinking habits are associated with the development of alcoholic pancreatitis, a dietary study has been conducted. Patients with clinically evident alcoholic pancreatitis were compared with individuals with clinically evident alcoholic cirrhosis with respect to dietary and drinking habits before the onset of clinical illness. There was no significant difference between the two groups regarding intake of nutrients, drinking habits or type of alcoholic beverage consumed.

Adult↗
PubMed1985

Leicester ECT trial: results in schizophrenia.

As part of the Leicester electroconvulsive therapy (ECT) study, the role of ECT in schizophrenia was investigated in a double-blind trial. The Present State Examination criteria for schizophrenia were fulfilled by 22 patients, of whom 19 gave consent and entered the trial. Neuroleptic medication was restricted during the trial period. Patients were randomly allocated to eight real ECT or eight simulated ECT. At the end of the four-week trial period, patients receiving real ECT showed a significantly greater improvement when measured on the Montgomery-Asberg Schizophrenia Scale (MASS), the visual analogue global psychopathology scale, and the depression scale. The differences on the MASS and visual analogue global psychopathology scale were not due to improvement in depressive symptoms. The superiority of real ECT was not demonstrated at the 12- and 28-week follow-up, when treatment was not controlled.

Adult↗