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Biomedical subjects

R Sutton

Publications and source records attributed to R Sutton.

At least 91 records · Page 5Linked to original sources
PubMed1995

Growth factor expression in skin during wool follicle development.

A variety of growth factors are likely to be involved in initiation and morphogenesis of wool follicles. To enable direct comparisons of the expression of different growth factors, reverse transcriptase-polymerase chain reactions (RT-PCR) were developed for ovine and murine TGF alpha, TGF beta 1, TGF beta 2, TGF beta 3, IGF1, IGF2, and FGF-2, which could all be carried out on a single cDNA sample. These RT-PCR were used with 16 sheep RNA samples from different foetal stages, neonatal sheep and mouse skin. The mRNAs for these growth factors were detected throughout gestation in sheep skin, except for TGF beta 1 mRNA which was not expressed in 51-day-old skin, but was expressed in 54-day and older samples. Since the first microscopically visible changes of follicle initiation occur around 62 days gestation, these results suggest that TGF beta 1 expression may be a signal for follicle initiation.

Animals↗
PubMed1995

Intrathecal baclofen--a multicentre clinical comparison of the Medtronics Programmable, Cordis Secor and Constant Infusion Infusaid drug delivery systems.

A retrospective review was carried out of 34 consecutive traumatic spinal cord damaged patients who have had the Medtronics Programmable, Cordis Secor or Constant Infusion Infusaid intrathecal baclofen drug delivery systems inserted between July 1987 and 1992. The results indicate that whilst this treatment has many benefits there is a significant risk of complications, some potentially fatal. It should only be provided by a skilled and experienced team. The Medtronics Programmable pump is an excellent pump. It is of particular benefit where the therapeutic window is small or fine-tuning required. The Constant Infusion Infusaid is adequate if less precise control and continuous infusion is sufficient. It is of particular benefit in financially disadvantaged countries. The Cordis Secor device is helpful when unpredictable intermittent relief of spasticity is required but is otherwise limited by its complication rate.

Adolescent↗
PubMed1995

The clinical spectrum of neurocardiogenic syncope.

Neurocardiogenic syncope is a collective term used to describe the clinical syndromes of syncope that result from inappropriate, and often excessive, autonomic reflex activity, and manifest as abnormalities in the control of vascular tone and heart rate. These include carotid sinus syndrome, vasovagal syncope, and the syndromes of cough, deglutition, and micturition syncope. Orthostatic hypotension, which, in contrast, results from a failure of autonomic reflexes, is not considered part of this family of closely related syndromes. This review will focus on vasovagal and carotid sinus syndromes.

Cardiovascular Diseases↗
PubMed1995

Oxygenator evaluation: Maxima 1380 versus Maxima Plus.

Continual improvement of oxygenators has been important in the growing demands of patient safety and support during cardiopulmonary bypass. The purpose of this study was to compare the Maxima 1380 oxygenator to the upgraded Maxima Plus oxygenator. Thirty-two adult patients were randomized to either the 1380 group or the Plus group. Information was recorded on the patients' weight, age, body surface area, esophageal temperature, arterial temperature, venous oxygen saturation, arterial pO2, arterial pCO2, blood flow, hematocrit, gas sweep, and FiO2. No significant difference was found between the two groups' mean weight, body surface area, arterial pO2 arterial pCO2, age, esophageal temperature, arterial temperature, venous oxygen saturation, and blood flow (p > 0.05). The Plus group demonstrated significantly lower mean gas sweep rates and FiO2 settings than the 1380 group. FiO2 of the 1380 was dependent on age, body surface area, blood flow, and esophageal temperature (r = 0.89, p < 0.001). FiO2 of the Plus was correlated with weight, esophageal temperature, arterial temperature, and arterial pO2 (r = 0.93, p < 0.001). Gas sweep rate of the 1380 was dependent on age, weight, esophageal temperature, blood flow, arterial temperature, and arterial pCO2 (r = 0.84, p < 0.001). The gas sweep rate of the Plus was dependent on weight and esophageal temperature (r = 0.55, p < 0.001). Based on these analyses, the new Maxima Plus oxygenator is more efficient in oxygen and carbon dioxide transport than the Maxima 1380.

Adult↗
PubMed1995

Evaluation of five in-line hematocrit monitors.

Monitoring the hematocrit is essential during cardiopulmonary bypass for efficacious administration of blood products. The purpose of this study was to evaluate five cardiopulmonary bypass in-line monitors designed to display continuous hematocrit or hemoglobin values. The devices were evaluated for accuracy using an in vitro circuit primed with human blood while randomizing hematocrit, blood flow rate, and temperature. Hematocrits correlated significantly with the error in all the devices (p < 0.01). Over evaluation time, the error of the CDI, Gish, IBC, and MX2 increased significantly (p < 0.05). Temperature correlated significantly with the error of the Gish device (r = -0.49, p < 0.01). Blood flow correlated significantly with the Gish error (r = -0.24, p < 0.01). The Cobe device had a significantly smaller overall error than the other devices (p < 0.001). Device evaluation, based on a low mean error, a low percent error, a high correlation with the actual hematocrit, low correlations between mean error, blood flow, and temperature, and insignificant correlation between time and error, suggests that the Cobe device is more accurate for the continuous monitoring of hematocrit during cardiopulmonary bypass.

Blood Circulation↗
PubMed1995

Psychogenic syncope diagnosed by prolonged head-up tilt testing.

Four patients with 'syncope' during prolonged head-up tilt testing despite normal blood pressure and heart-rate behaviour are described. They represent 5.5% of all positive tilt-test outcomes from a prospective study of 181 consecutive patients with unexplained syncope. All four patients were female, and were both younger and more symptomatic than patients with vasovagal syncope or orthostatic hypotension. In three of the patients, clinical episodes of syncope were observed which closely resembled those provoked during tilt. It is suggested that the tilt response is psychogenic and reveals a psychiatric cause for recurrent syncope.

Adolescent↗
PubMed1995

Alcohol and oesophageal varices.

Oesophageal varices are abnormally dilated veins that develop beneath the mucosa of the lower oesophagus and upper stomach and cause profound gastrointestinal haemorrhage associated with a high mortality. Varices develop in the presence of protal hypertension, which, in Europe and the USA, is most commonly due to alcoholic cirrhosis of the liver. Alcoholic cirrhosis develops in 10-20% of chronic ethanol abusers as a result of prolonged hepatocyte damage, leading to centrilobular inflammation and fibrosis. The net effect on the portal venous system is an elevation of resistance, and/or increase of inflow, producing portal hypertension, and the development of collateral channels in the form of varices. Such parenchymal liver disease also causes ascites, clotting deficiencies, secondary malnutrition and hepatic encephalopathy, all of which contribute to the high mortality associated with variceal haemorrhage. Variceal bleeding is more likely to occur when the varices are large, long and numerous, with surface red markings, and may be precipitated to respiratory tract infection, non-steroidal anti-inflammatory drugs, alcohol, or may occur spontaneously. Once identified by endoscopy, the aims of management are to control the haemorrhage, to prevent recurrent haemorrhage, and to treat the underlying cause of portal hypertension. Attention to nutrition and long-term rehabilitation are particularly important in those alcoholic cirrhotic patients who survive.

Alcoholism↗
PubMed1995

A comparison of non-invasive continuous finger blood pressure measurement (Finapres) with intra-arterial pressure during prolonged head-up tilt.

Simultaneous intra-radial and non-invasive (Finapres, Ohmeda) blood pressures were compared during prolonged head-up tilt, in eight patients (mean age 49 years) with malignant vasovagal syncope. Twelve tilts were performed, of which eight resulted in vasovagal syncope. The mean bias (difference between Finapres and intra-arterial pressures) for systolic pressure was +0.7 mmHg (standard deviation 11.3 mmHg) and for diastolic pressure was +5.4 mmHg (standard deviation 7 mmHg). The within-tilt precision (standard deviation of the bias) of the non-invasive measurements varied between 2.9-12.4 mmHg (median 4.5 mmHg) for systolic comparisons, and 1.6-8.4 mmHg (median 4.4 mmHg) for diastolic comparisons. In all but one tilt highly significant positive increases in both systolic (median 7.1 mmHg) and diastolic bias (median 8.1 mmHg) occurred on tilt with respect to resting pre-tilt levels. Independent of the absolute level of agreement, the non-invasive measurements followed changes in intra-arterial pressure closely, with 89% of beat-to-beat changes in systolic pressure, and 95% of beat-to-beat changes in diastolic pressure followed to within +/- 2 mmHg. This study suggests that the Finapres is well suited for use during diagnostic tilt testing, demonstrating an acceptable within-tilt precision and closely following pressure changes during vasovagal syncope.

Adult↗
PubMed1994

Endogenous phosphorylation of tau proteins in brain slices.

Tau protein phosphorylation has been implicated as a main process that regulates microtubule dynamics. A large number of tau isoforms is generated by phosphorylation through the action of a diversity of kinases. We have analysed variations in tau phosphorylation by two-dimensional gel electrophoresis, where a great heterogeneity of isoforms can be detected. Using mouse brain slices from various developmental stages we have found preferential phosphorylation of low molecular weight tau isoforms in all the ages analysed. A greater isoform diversity was found in juvenile than in adult brain. Brain slices provide a tightly regulated environment that preserves cell compartmentalization and has shown to be very useful for studies on tau phosphorylation.

Animals↗
PubMed1994

Plasminogen activator inhibitor-1 in the cerebrospinal fluid as an index of neurological disease.

Plasminogen activator inhibitor-1 (PAI-1) is a serpin proteinase inhibitor which regulates fibrinolysis and the proteinase cascade of tumour invasion. In this study, PAI-1 was identified in the cerebrospinal fluid (CSF) from patients without neurological disease and patients with various neurological disorders. The mean level of PAI-1 in the CSF of 28 patients without central nervous system (CNS) disease was 0.28 +/- 0.03 (SEM) ng/ml. CSF PAI-1 was significantly increased in the following diagnostic categories:dementia (Alzheimer's disease), cerebral infarction, CNS infection, alcohol withdrawal seizures and CNS neoplasia. In all these disorders, with the exception of CNS infection, PAI-1 was also increased as a fraction of total CSF protein. CSF PAI-1 was not increased in patients with hydrocephalus or idiopathic seizure disorders. Complementary plasma samples were available for 18 of the 128 CSF specimens studied. For these cases, there was no correlation between plasma PAI-1 and CSF PAI-1 levels. PAI-1 may represent a non-specific marker of disease in the central nervous system.

Adolescent↗
PubMed1994

Incidence of complications after carotid sinus massage in older patients with syncope.

OBJECTIVE: To review the incidence of neurological complications occurring after carotid sinus massage performed for diagnostic purposes. DESIGN: Case review and comparison with previously published work. SETTING: Syncope Clinic, Royal Victoria Infirmary, Newcastle-upon-Tyne, and Chelsea and Westminster Hospital, London. PARTICIPANTS: Patients undergoing investigation of dizziness, syncope, or unexplained falls. METHODS: Carotid sinus massage performed for 5 seconds in both supine and erect postures, both before and after atropine. Contraindications to carotid sinus massage were the presence of carotid bruits, recent myocardial or cerebral ischemia, or previous ventricular tachyarrhythmias. RESULTS: Two cases of neurological complications were reported from a total of 500 patients (2000 massage episodes) investigated in one center, giving an incidence of 0.1%. Combining this data with another center performing investigations in a similar fashion, seven neurological complications arose from a total of 5000 massage episodes, an incidence of 0.14%. Reported complications were pyramidal signs in five cases and visual field defects in two. Pyramidal weakness persisted in one case with a pre-existing stroke on the same side, and a visual field loss was permanent in one. CONCLUSIONS: Neurological complications following carotid sinus massage for diagnosis of the carotid sinus syndrome are uncommon and usually transient. Contraindications to carotid sinus massage should be respected and the standardized technique used.

Aged↗
PubMed1994

Short AV interval VDD pacing does not prevent tilt induced vasovagal syncope in patients with cardioinhibitory vasovagal syndrome.

Eleven subjects (mean age 50 years, range 33-71 years), who had previously received permanent dual chamber pacemakers for cardioinhibitory vasovagal syncope, underwent paired Westminster protocol tilt tests, one with short AV delay VDD pacing and one without pacing, to test the hypothesis that continuous ventricular pacing would prevent the cardiac initiation of vasovagal syncope. Nine (82%) of the paced tilts produced positive vasovagal outcomes compared with seven (64%) of the unpaced tilts. No important differences in the heart rate or blood pressure behavior during tilt or the time to positive vasovagal outcomes were observed between the paired tilts. There was more accelerated syncope/presyncope once symptoms had developed during the paced tilts of subjects in whom both study tilts were positive, although this did not reach statistical significance (P = 0.054). This study shows that atrial synchronous ventricular pacing does not prevent the initiation, or progression, of tilt induced vasovagal syncope in predisposed subjects.

Adult↗
PubMed1994

Reasons for reprogramming dual chamber pacemakers to VVI mode: a retrospective review using a computer database.

Seven hundred seventy-one dual chamber pacemakers implanted over a 13-year period were identified using a computer database. The mean follow-up period was 40.4 +/- 30.9 months (mean +/- SD). Thirty-three (4.3%) patients were reprogrammed to the VVI mode after a mean period of 26.4 +/- 29 months. Indications for pacing in those reprogrammed were: complete heart block 45.7%, impaired AV conduction 5.7%, sick sinus syndrome 34.2%, carotid sinus syndrome 11.4%, and vasovagal syndrome 2.8%. The most common reason for reprogramming was development of sustained atrial arrhythmias (atrial fibrillation or flutter), which occurred in 25 patients (3.3% of entire group). The remaining 8 (1% of entire group) were reprogrammed because of atrial lead related problems.

Arrhythmias, Cardiac↗
PubMed1994

Crohn's disease and myasthenia gravis: a possible role for thymectomy.

A female patient with a three year history of Crohn's disease of the colon developed myasthenia gravis. Despite diversion of the faecal stream by an ileostomy, and total colectomy, the patient had continuing problems with perineal and perianal abscesses and fistulas. Her myasthenia gravis became unresponsive to anti-cholinergics so a thymectomy was performed. The perineal and perianal disease improved subsequently. This case supports the theory that functional disturbances of the thymus may have a role in the pathogenesis of inflammatory bowel disease.

Adult↗