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Biomedical subjects

A Smith

Publications and source records attributed to A Smith.

At least 1,009 records · Page 56Linked to original sources
PubMed1988

Position sense at the proximal interphalangeal joint of the human index finger.

1. The ability of eleven normal subjects to match the position of the proximal interphalangeal joints was tested. The right index finger (target finger) was moved to a given position and the subject was required to match this with the left index finger (matching finger). 2. Digital nerve block of the matching finger resulted in substantial impairment in matching performance in seven out of eight subjects. 3. Anaesthesia of the target finger in two subjects also produced obvious position matching deficit, in a pattern consistent with subjective sensation of target finger position. 4. The effects of digital nerve block were specific, as neither injection of saline into the matching finger, nor anaesthesia of adjacent fingers, impaired performance. 5. In one subject, injection of local anaesthetic into the synovial cavity of the matching finger also resulted in impairment of matching performance, indicating that articular receptors contribute to position sense at this joint. 6. Passive displacement of the matching finger did not produce significantly greater errors than those occurring with active finger positioning either under control conditions or during digital nerve block of the matching finger. 7. Although digital nerve block produced substantial impairment of matching performance, there was not complete loss of proprioceptive sensation, suggesting that muscle receptors also contribute. This was confirmed in experiments where isotonic loading of the matching finger while it was anaesthetized resulted in significant alteration in matching performance compared to anaesthesia alone. 8. It is concluded that no one source of afferent input can be excluded from contributing to proprioception at the index finger. It is likely that under different operating conditions several afferent sources are required to provide optimal proprioceptive resolution.

Adult↗
PubMed1988

Effects of chrysotherapy on circulating lymphocyte numbers and subsets.

In a prospective 24 week study of 25 patients with rheumatoid arthritis (RA) weekly intramuscular (IM) sodium aurothiomalate resulted in a small but significant reduction in the circulating lymphocyte count. Analysis of absolute levels of pan T cells, T4 helper cells, T8 suppressor cells, T4/8 ratio, B cells, and major histocompatibility complex (MHC) class II positive cells showed reductions in these subsets, though these changes did not reach significance. At entry there was no association between circulating lymphocyte counts and subsets and clinical and laboratory indices which reflected disease activity, and during the study gold responders could not be differentiated from non-responders with regard to changes in lymphocyte counts and subsets. Thus this study suggests that weekly IM gold leads to a modest reduction in circulating lymphocyte numbers which involves most subsets. This effect appears to be independent of the clinical efficacy of this drug.

Arthritis, Rheumatoid↗
PubMed1988

Urological abnormalities in young women with severe constipation.

Anorectal and urodynamic studies were carried out in 10 young women with severe constipation and the results compared with those obtained in controls. The lowest volumes that provoked a desire to defecate (constipated 200 +/- 50 v controls 110 +/- 10 [mean +/- SEM] ml: p less than 0.05), and a desire to micturate (constipated 560 +/- 40 v controls 295 +/- 15 [mean +/- SEM] ml: p less than 0.001), were significantly greater in constipated patients compared with controls. The maximum tolerable rectal volume (380 +/- 30 v 290 +/- 20 [mean +/- SEM] ml: p less than 0.05) and the bladder capacity (720 +/- 50 v 540 +/- 10 [mean +/- SEM] ml: p less than 0.001) were also increased in the constipated subjects compared with controls. Electromyographic studies show failure of relaxation of the external anal sphincter (EAS) on attempted defecation in all 10 patients; and eight of these patients actually contracted their EAS when they strained to defecate, causing a functional outlet obstruction. Urodynamic studies showed normal urinary flow rates, normal detrusor pressures and normal radiology during voiding. Thus, these studies suggest that constipated patients have an increase in capacity and a reduction in sensitivity in the urinary bladder as well as in the rectum, but showed no evidence of obstruction to urine flow.

Adult↗
PubMed1988

Localisation of atrial natriuretic peptide immunoreactivity in the ventricular myocardium and conduction system of the human fetal and adult heart.

Atrial natriuretic peptide immunoreactivity was found in ventricular and atrial tissues with specific antisera raised to the amino and carboxy terminal regions of the precursor molecule. In 13 developing human hearts (7-24 weeks' gestation) the immunoreactivity was concentrated in the atrial myocardium and ventricular conduction system but it was also detected in the early fetal ventricular myocardium. Immunoreactivity in five normal adults was largely confined to the atrial myocardium although it was also found in the ventricular conduction tissues of hearts removed from 10 patients who were undergoing cardiac transplantation. The ventricular conduction system is an extra-atrial site for the synthesis of atrial natriuretic peptide. In the failing heart this synthesis may be further supplemented by expression of the gene in the ventricular myocardium. It is possible that ventricular production of the peptide contributes to the raised circulating concentrations of atrial natriuretic peptide immunoreactivity found in severe congestive heart disease, particularly in patients with dilated cardiomyopathy.

Adolescent↗
PubMed1988

Mechanism of decreased forward stroke volume in children and swine with ventricular septal defect and failure to thrive.

Children with ventricular septal defect (VSD) often demonstrate failure to thrive (FTT). Such patients usually have reduced systemic cardiac output which has been postulated as a cause for their growth retardation. This study was conducted to ascertain the mechanism of the reduced cardiac output in children with VSD and FTT and also in a porcine model of VSD. Forward stroke volume was reduced in VSD-FTT children, 31 +/- 8 ml/m2, compared to normal children, 49 +/- 15 ml/m2 (P less than 0.05), but was not reduced in children with VSD and normal growth and development (41 +/- 16 ml/m2). Forward stroke volume was also reduced in swine with VSD compared to controls. Contractility assessed by mean velocity of circumferential shortening (Vcf) corrected for afterload was similar in normals and VSD-FTT children. Contractile performance was also similar in normal and VSD swine. Afterload assessed as systolic stress was similar in FTT-VSD children and normal subjects. Preload assessed as end-diastolic stress was increased in the VSD-FTT group. End-diastolic volume was not larger in the VSD-FTT group. We conclude that the reduced stroke volume seen in VSD-FTT children and VSD-swine was not due to reduced contractility, increased afterload or reduced preload. The reduced stroke volume may have been due to failure of end-diastolic volume to increase adequately.

Animals↗
PubMed1988

Diaschisis, site, time and other factors in raven performances of adults with focal cerebral lesions.

Analyses of Raven matrices performances by 35 patients with acute and 22 with chronic focal lesions restricted to the anterior or posterior regions of the left or right hemispheres illustrate the importance of controlling for diaschisis, specific site, time, age and other factors determining neuropsychological performances. These findings have important practical and theoretical implications with respect to the elucidation of principles underlying organization, disorganization and reorganization of human brain functions. They also suggest that many of the previous controversial and conflicting reports may be reconciled when these and other significant underlying factors are accounted for. Finally, they confirm Jackson's earlier observations of the critical role of the right posterior lobe in "visuopsychic" non verbal mental processes.

Brain↗
PubMed1988

A microscopic and immunodiagnostic search for giardiasis in patients with gastrointestinal disorders.

Direct microscopy and an ELISA technique were used to determine the prevalence of Giardia lamblia and its antigen in stool samples from patients with Crohn's disease, ulcerative colitis, acute-onset diarrhoea, or dyspepsia. Cysts of Giardia lamblia were observed by microscopy of faeces from two of the patients with acute-onset diarrhoea and one with dyspepsia. Giardia antigen was detected in the faeces of five patients, including all three in whom cysts had been identified by microscopy. No evidence of giardiasis was found in any patient with Crohn's disease or ulcerative colitis. It is concluded that the ELISA can reliably distinguish giardiasis from a range of other gastrointestinal disorders.

Antibodies, Protozoan↗
PubMed1988

Diurnal variation in the symptoms of colds and influenza.

The present research examined diurnal variation in the severity of symptoms of experimentally-induced colds and influenza. Nasal secretion was greatest in the morning, decreased over the day, and then showed a slight increase in the late evening. Colds did not change the average temperature, nor did they alter the temperature rhythm. Similar, negative results were found with alertness ratings. Influenza B illnesses produced an increase in nasal secretion and systemic effects. The average temperature increased during this illness and subjects reported that they felt more drowsy. Diurnal variation in the severity of local and central symptoms was observed, with nasal secretion and the temperature increase being greatest in the early morning. These results have important implications for the assessment and treatment of the illnesses.

Adult↗
PubMed1988

Viral hemorrhagic fever antibodies in Nigerian populations.

Using the immunofluorescence test, a serosurvey for antibodies to five viral agents associated with hemorrhagic febrile infections was conducted with 1,677 human sera from different parts of Nigeria. Three hundred fifty-seven (21.3%) were positive for Lassa virus antibody, while antibodies to Rift Valley fever virus were detected in 42 (2.5%) of the sera. Testing for Rift Valley fever virus antibody was confirmed by plaque reduction neutralization test. Antibodies to Ebola and Marburg viruses were detected in 30 and 29 sera, respectively. Of the 357 Lassa virus antibody-positive sera, 297 (83.2%) were positive for Lassa only. In contrast, sera positive for Marburg were positive in combination with Lassa, Ebola, or Rift Valley fever viruses. Antibodies to Lassa and Rift Valley fever viruses were found in all locations in Nigeria, whereas Ebola and Marburg antibodies were found mainly in the northern savanna zones of Benue and Gongola, but not in the rain forest area of Ondo.

Adolescent↗
PubMed1988

Hemispherectomy and diaschisis: rapid improvement in cerebral functions after right hemispherectomy in a six year old child.

Neuroradiological, neurological, and neuropsychological studies before and after hemispherectomy for seizures of a six year old boy with left hemiplegia at birth revealed striking postoperative improvement. Seizures ceased and have not recurred. Preoperative EEC studies from seven months of age revealed increasing pathological involvement of the left as well as right hemisphere. Postoperatively, normal tracings over the left hemisphere documented marked and continuing improvement. In contrast to markedly subnormal preoperative WISC-R IQs, retest at 19 months postoperatively showed WISC-R IQs within the normal range, with similar improvement in other tests of cognitive, motor and sensory functions. The arrest and reversal of the preoperative pattern of increasing deterioration and disappearance of pathological involvement of left as well as right hemisphere functions following surgery is consistent with the disappearance of diaschisis as described by von Monakow in 1914, and has conceivably significant clinical as well as theoretical implications.

Journal Article↗
PubMed1988

The arterial supply to the right atrium and the sinus node in classic tricuspid atresia.

Dissection was performed in 41 hearts from patients with classic tricuspid atresia so as to demonstrate the major arteries supplying the right atrium and the sinus node. A right anterior atrial artery was identified in 85.4% of the hearts, a right lateral atrial artery was seen in 68.3%, a right posterior atrial artery in 41.5%, and a left anterior atrial artery in 78.0% of the specimens. The artery to the sinus node, identified in 34 hearts, originated from the right coronary artery in 38% of the cases, from the left coronary artery in 59%, and had a dual origin in 3% of cases. The relative importance of these arteries is discussed with regard to the atriopulmonary anastomosis of the Fontan procedure. Special consideration is given to the incisions employed in different variations of this operation and the arterial distribution is compared to that found in the normal heart.

Coronary Vessel Anomalies↗
PubMed1987

The effect of digital nerve block on position sense at the proximal interphalangeal joint of the human index finger.

Position matching at the proximal interphalangeal joint of the index finger in human subjects was tested by passive displacement of the right (target) finger and active matching of the left index finger. In 5 subjects it was found that position matching was grossly impaired after digital nerve block of the matching finger. Typically, subjects hyperextended the matching finger when the target finger was held in extension and hyperflexed the matching finger when the target finger was held in flexion. These results suggest that even with active positioning, joint and cutaneous receptors importantly contribute to the awareness of position at this joint.

Adult↗