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Biomedical subjects

J A Wilson

Publications and source records attributed to J A Wilson.

At least 109 records · Page 6Linked to original sources
PubMed1999

Constipation in the elderly.

Constipation is a common concern in the elderly and accounts for significant expenditures on over-the-counter drugs. Although normal aging is not associated with abnormal bowel motility, pathologic and psychosocial conditions lead to increased symptoms in elderly patients. Careful clinical evaluation to eliminate serious conditions including colon neoplasia is important. Medical management with emphasis on fiber, bulk agents, fluid intake, and exercise, as well as appropriate use of laxatives is reviewed.

Aged↗
PubMed1998

Localised cerebral phosphorus-31 MR spectroscopy in man before and immediately after coronary bypass surgery with hypothermic cardiopulmonary bypass.

Coronary artery bypass surgery classically is undertaken with hypothermic cardiopulmonary bypass (CPB). There is a high incidence of neuropsychological defects after cardiac surgery, which may be related to cerebral ischaemia during the rewarming period. In this study, phosphorus-31 magnetic resonance spectroscopy (31P MRS) was used to identify changes in cerebral 31P MR spectra in patients before and immediately after hypothermic CPB. Four neurologically normal patients undergoing coronary artery bypass surgery were studied. Localised cerebral 31P MRS (TR 5000 ms) was performed at 1.5 Tesla on each patient the day before and within an hour of completion of surgery. Peak areas for phosphomonoesters (PME), inorganic phosphate (Pi), phosphodiesters (PDE), phosphocreatine (PCr) and beta ATP (betaATP) were measured. Metabolite peak area ratios and relative percentages of each 31P MR resonance with respect to the total 31P MR signal were calculated. In the post-operative MR spectra, each patient displayed a marked reduction in Pi/betaATP and increase in PCr/Pi ratios. Spectral changes in percentage metabolite signals following surgery varied both in magnitude and pattern between patients. In two patients there was an increased postoperative percentage PME and percentage PCr with a decrease in percentage betaATP. The converse was found in the other two patients, but all four subjects displayed a markedly decreased percentage Pi after CPB. These metabolite changes probably reflect rebound phosphorylation in the immediate postoperative period and suggest increased metabolic activity in the hyperaemic brain on rewarming from hypothermic CPB.

Aged↗
PubMed1998

Are false recognitions influenced by prerecognition processing?

Lexical activation is a core process in models of spoken word recognition. Specific words activated are candidates, with degree of activation determined by the match with sensory information. Once identified, lexical activation shifts to provide a meaningful representation, normally through activation of semantically related words. Activated words are assumed to acquire familiarity as a result of being activated, providing a basis for memories, both real and imagined. Three experiments showed a direct relationship between number of false recognitions and their presumed degree of activation. Results converge with those from spoken word recognition in implicating lexical activation during early stages of processing. For recognition memory, the message is that prerecognition lexical processing should be included in the memory equation.

Adult↗
PubMed1998

Chest computerized tomography scanning in patients presenting with head and neck cancer.

Between 1 to 16% of patients with head and neck squamous cell carcinoma (HNSCC) have synchronous tumours; the majority (> 50%) occurring within the lung. Previous studies have relied upon endoscopy and chest radiographs. The aim of this study was to determine the incidence of synchronous intrapulmonary tumours in this group of patients using computerized tomography (CT) scanning. Over 36 months, 111 consecutive patients were assessed at presentation by contrast enhanced CT scanning from the skull base to the diaphragm. Chest scans showed intrapulmonary lesions in 17 patients and 10 have, with time, been confirmed as neoplastic. These allowed treatment of three primary bronchial carcinomas following radical treatment of the index tumour and cancellation of radical treatment in five patients with metastases. Two patients with possible metastases at presentation underwent radical treatment to the index tumour with subsequent follow-up confirming metastatic chest disease. All 10 patients eventually died of either locoregional or metastatic disease. This is one of the first prospective reports of chest scanning in patients with head and neck cancer. An additional chest scan in this group, many of whom undergo a staging scan of the neck, requires an extra 10 min with no further contrast and in this study yielded a synchronous tumour rate of 9%.

Carcinoma, Squamous Cell↗
PubMed1998

Vocim analysis of laryngeal images: is breathiness related to the glottic area?

The aim of this study was to determine the relationship between glottic space and breathy voice. Using a new computerized method of analysing the glottic area of video images with the Vocim computer system, 16 patients with a vocal cord palsy and 31 with non-organic dysphonia were examined. The quality of the breathy voice was assessed and correlated with the size of the glottic space during phonation. There was a positive (r = 0.70) correlation between glottic area and breathy voice in vocal cord palsy. There was no correlation (r = 0.002) in non-organic dysphonia. Therefore in this study population, for vocal cord palsy, glottic area is the dominant feature in determining voice quality. This relationship is not maintained in non-organic dysphonia.

Glottis↗
PubMed1998

Primary stenting of the extracranial internal carotid artery in a patient with multiple cervical dissections: technical case report.

OBJECTIVE AND IMPORTANCE: Spontaneous dissection of the extracranial internal carotid artery (ICA) and vertebral artery (VA) is a well-documented cause of stroke in young, previously healthy patients. The majority of patients with spontaneous dissection are successfully treated with antiplatelet or anticoagulation therapy, but a significant proportion of patients progress to suffer devastating morbidity and mortality. Surgical intervention has primarily consisted of proximal ligation, extracranial-intracranial bypass, or endarterectomy. Generally, these procedures are technically demanding and yield disappointing clinical results. CLINICAL PRESENTATION/INTERVENTION: A 36-year-old man without a significant medical history initially presented with a several-day history of episodic right upper extremity weakness and numbness and visual obscurations. Cerebral angiography revealed bilateral ICA long segment narrowing (95%), distal left VA high-grade (95%) stenosis compatible with dissections, and right VA proximal occlusion. While therapeutically anticoagulated on heparin, the patient continued to experience crescendo episodes of right upper extremity paresis and paresthesias as well as aphasia. The patient underwent primary stenting of the left ICA, using a series of six overlapping stents (three Gianturco-Roubin coronary stents and three Palmaz-Schatz coronary stents). The patient remained symptom-free without neurological complications, and subsequent angiography performed at the 9-month follow-up examination confirmed continued patency of the stented left ICA as well as recanalization of the right ICA and VA. CONCLUSION: Neurovascular stents offer a minimally invasive and potentially efficacious treatment for the prevention of cerebral ischemia in patients with spontaneous extracranial dissection who remain symptomatic despite therapeutic anticoagulation.

Adult↗
PubMed1998

Evaluation of PCR primers for early diagnosis of cytomegalovirus infection following liver transplantation.

The availability of microbiologic methods that detect early replication of cytomegalovirus (CMV) posttransplantation will enhance the process of initiating preemptive antiviral therapy prior to the appearance of CMV disease. Using PCR techniques we sought to determine which region of the CMV genome present in peripheral blood leukocytes (PBLs) or serum provides the highest sensitivity for the detection of CMV posttransplantation. Blood samples were prospectively collected weekly for at least 8 weeks from a cohort of 21 consecutive liver transplant recipients not receiving anti-CMV prophylaxis. Results of PCR assays were correlated with recovery of CMV in cell cultures and histopathological findings from biopsy specimens of infected organs to assess clinical symptomatic infection. Of 148 specimens, primer pairs directed to the HindIII-X fragment region of CMV detected target DNA with a 94% sensitivity, compared to an 87% sensitivity with primer pairs directed to EcoRI fragment D, 32% sensitivity with primer pairs directed to the immediate-early antigen 1 gene (IEA1 gene), and 20% sensitivity with primer pairs directed to the major immediate-early (MIE) gene. The performance characteristics in terms of the sensitivity of primers for amplifying CMV DNA associated with symptomatic infection ranged from 100% (HindIII-X) to 20% (MIE gene); however, specificity was inversely related (HindIII-X, 45%; MIE gene, 91%) to primers directed to these gene targets. When HindIII-X and EcoRI-D primer sets were used, CMV DNA from PBLs was a more sensitive target than CMV DNA from serum for the early detection of symptomatic CMV infection (17 versus 12 days). Importantly, CMV DNA was not detected in five patients with no evidence of this viral infection. In conclusion, primers directed to the HindIII-X fragment region were the most optimal for the early detection of CMV DNA in PBLs and sera from symptomatic liver transplant recipients.

Antibodies, Viral↗
PubMed1998

Nineteen baculovirus open reading frames, including LEF-12, support late gene expression.

A set of 18 plasmid subclones of the Autographa californica nuclear polyhedrosis virus genome, each containing an identified late expression factor gene (lef), supports expression from a late viral promoter in transient expression assays in the SF-21 cell line derived from Spodoptera frugiperda. We have constructed a further set of plasmids in which each lef open reading frame (ORF) is controlled by the Drosophila melanogaster heat shock protein 70 (hsp70) promoter and epitope tagged. Failure of this set of plasmids to support transient late gene expression, and the inability of the p47 ORF to replace the p47-containing plasmid supplied in the lef plasmid library, led to the identification of a 19th late expression factor gene (lef-12) located adjacent to the p47 gene. The sequence of lef-12 is predicted to encode a protein of 21 kDa with no homology to any previously identified protein. The set of 19 hsp70-controlled lef ORFs (HSEpiHis lef library) supports transient expression from a late viral promoter. lef-12 did not affect expression from an early baculovirus promoter. In TN-368 cells, which are also permissive for virus replication, lef-12 provided a stimulatory effect but did not appear to be essential.

Amino Acid Sequence↗
PubMed1998

Blood-gas measurements adjusted for temperature at three sites during incremental exercise in the horse.

Rectal temperature (Tre) is often used to adjust measurements of blood gases, but these adjusted measurements may not approximate temperatures during intense exercise at main sites of gas exchange: muscle and lung. To evaluate differences in blood gases between sites, temperatures (T) were measured with thermocouples in the rectum (re), in mixed venous blood (v), in gluteal muscle (mu), and on the skin (sk) in seven Arabian horses as they underwent an incremental exercise test on a treadmill. Blood samples were drawn from the carotid artery and pulmonary artery (mixed venous) 30 s before each increase in speed and during recovery. Blood gases and pH were measured at 37 degreesC, and all variables were adjusted to Tre, Tv, and Tmu. Adjusted variables during exercise and recovery were significantly different from each other at the three sites. Linear and polynomial equations described the time course of venous temperature and from Tre and Tsk during exercise and from Tsk during recovery. Interpretation of changes in muscle metabolism and gas exchanges based on blood-gas measurements is improved if they are adjusted appropriately to Tmu or Tv, which may be predicted from Tsk in addition to Tre during strenuous exercise and from Tsk during recovery.

Animals↗
PubMed1998

Systematic analysis of snoring in women.

Nineteen percent of women are habitual snorers, yet most snoring studies report only on male snorers. The aim of this study was to identify the factors responsible for habitual snoring in women. Twenty-four snorers and 16 controls were studied prospectively in a special snoring clinic. Snorers were shorter (p = .005) and heavier (p = .001), and with greater body mass index (BMI: p < .001), collar size (p = .002), and submental skinfold thickness (p = .001) than controls. The area of the posterior pharyngeal wall visible on oral examination was smaller in snorers (p = .005). Acoustic rhinometry areas and volumes were similar in the two groups. Nasal flow-volume loops showed reduced expiratory (p = .01) and inspiratory (p = .07) flow in snorers. Inspiratory flow correlated inversely with nasal symptoms (p < .05). The factors that best predict habitual snoring in women are a high BMI, a high nasal symptom score, and heavy weight. Of these, BMI is the most powerful.

Adolescent↗
PubMed1998

Magnetic resonance spectroscopy of high-energy phosphates and lactate immediately after coronary artery bypass surgery.

Hypothermic cardiopulmonary bypass (CPB) is associated with a high incidence of neuropsychological defects, marked cerebral swelling immediately after surgery and jugular bulb desaturation during rewarming. This suggests cerebral ischaemia may occur, but evidence is indirect. We studied four patients with 31P magnetic resonance spectroscopy (MRS) and four with 1H MRS before and immediately after coronary surgery. There was no visible lactate in 1H MR spectra. In 31P MR spectra, the ratio of phosphocreatine to adenosine triphosphate was maintained (before: 2.13 +/- 0.86 vs after: 2.57 +/- 1.31; mean +/- 1 SD) and there was no intracellular acidosis (intracellular pH: 7.1 +/- 0.04 vs 7.16 +/- 0.08), while phosphocreatine/inorganic phosphate was increased immediately after the operation (2.92 +/- 0.37 vs 6.39 +/- 2.67, p = 0.03). This suggests rebound replacement of energy stores following recovery from temporary cerebral ischaemia during CPB: intra-operative studies would be needed to test this hypothesis further.

Brain Ischemia↗
PubMed1998

Sarcoplasmic reticulum responses to repeated sprints are affected by conditioning of horses.

Sarcoplasmic reticulum (SR) responses to repeated sprints and to physical conditioning were studied in 10 Quarter Horses. Exercise tests (four repeated sprints on a treadmill) were conducted before and after 12 wk of sprint conditioning. Muscle samples from the middle gluteal muscle were taken before and after each exercise test, and SR vesicles were isolated. Calcium uptake was determined spectrophotometrically using antipyrylazo III, and Ca2+-ATPase activity was determined using an enzyme-linked optical assay. Conditioning increased calcium uptake rate and Ca2+-ATPase activity by 14 and 38%, respectively, before exercise and by 25 and 26% after exercise. Exercise decreased calcium uptake rate and Ca2+-ATPase activity by 37 and 27%, respectively, before conditioning and by 28 and 21% after conditioning. Decreases in calcium uptake and Ca2+-ATPase activity of SR have been associated with fatigue during exercise, and this association is strengthened by the moderating effect of conditioning.

Animals↗
PubMed1998

Is a 'safe swallow' really safe?

The aim of this study was to look at whether full vocal cord adduction is achieved in 45 normal subjects when asked to hold their breath, as in the supraglottic safe swallow technique. Fiberoptic nasendoscopy was used to assess vocal cord adduction. Results show that 57.7% of normal subjects do not fully close their vocal cords for the complete duration of breath holding. This finding has implications for the efficacy of teaching methods of the supraglottic safe swallow technique.

Adult↗