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Biomedical subjects

M K Benson

Publications and source records attributed to M K Benson.

At least 19 recordsLinked to original sources
PubMed1992

Effect of carbohydrate rich versus fat rich loads on gas exchange and walking performance in patients with chronic obstructive lung disease.

BACKGROUND: High calorie intakes, especially as carbohydrate, increase carbon dioxide production (VCO2) and may precipitate respiratory failure in patients with severe pulmonary disease. Energy obtained from fat results in less carbon dioxide and thus may permit a reduced level of alveolar ventilation for any given arterial blood carbon dioxide tension (PaCO2). METHODS: Ten patients with stable severe chronic obstructive lung disease underwent a six minute walk before and 45 minutes after taking 920 kcal of a fat rich drink, an isocalorific amount of a carbohydrate rich drink, and an equal volume of a non-calorific control liquid on three separate days, in a double blind randomised crossover study. Borg scores of the perceived effort to breathe were measured at the beginning and end of each six minute walk. Minute ventilation (VE2), VCO2, oxygen consumption (VO2), respiratory quotient (RQ), arterial blood gas tensions, and lung function were measured before and 30 minutes after each test drink. RESULTS: Baseline measurements were similar on all three test days and the non-calorific control drink resulted in no changes in any of the measured variables. The carbohydrate rich drink resulted in significantly greater increases in VE, VCO2, VO2, RQ, PaCO2, and Borg score and a greater fall in the distance walked in six minutes than the fat rich drink (mean fall after carbohydrate rich drink 17 m v 3 m after fat rich drink and the non-calorific control). The increase in VCO2 correlated significantly with the decrease in six minute walking distance and the increase in Borg score after the carbohydrate rich drink. The only significant change after the fat rich drink when compared with the non-calorific control was an increase in VCO2. CONCLUSIONS: Comparatively small changes in the carbohydrate and fat constitution of meals can have a significant effect on VCO2, exercise tolerance, and breathlessness in patients with chronic obstructive lung disease.

Aged↗
PubMed1992

Acute pneumonitis associated with low dose methotrexate treatment for rheumatoid arthritis: report of five cases and review of published reports.

BACKGROUND: Low dose methotrexate has become established in the treatment of refractory rheumatoid arthritis. Until recently it has been considered that the use of a low dose regimen (< 20 mg/week) would avoid the pulmonary toxicity associated with the higher doses prescribed in malignant disease. Although initial experience with low dose methotrexate was encouraging, an increasing number of cases of an acute, life threatening pneumonitis are being reported in patients with refractory rheumatoid arthritis. PATIENTS: Since 1984 43 patients with refractory rheumatoid arthritis have been established on low dose methotrexate in the Oxford Health District. Five of these patients have subsequently developed acute methotrexate induced pneumonitis. The clinical and radiological features of these cases are described and previous reports reviewed. RESULTS: Five patients having low dose methotrexate treatment developed acute pneumonitis. Presentation was subacute and dominated by constitutional features. Respiratory symptoms developed insidiously but progressed rapidly with increasing dyspnoea associated with severe hypoxia. Chest radiographs were non-specific, showing diffuse interstitial infiltration and alveolar shadowing. Microbiological investigation gave negative results. In all cases methotrexate was discontinued and high dose corticosteroids started, with rapid clinical and radiological improvement. After withdrawal of steroid both clinical and radiological resolution was maintained at follow up. CONCLUSION: Acute pneumonitis is an uncommon but serious adverse effect of low dose methotrexate treatment for refractory rheumatoid arthritis. The initial presentation is non-specific and a high index of suspicion is required as respiratory failure may develop rapidly. Management depends on exclusion of infection, withdrawal of methotrexate, and high dose corticosteroid treatment. Full supportive treatment is indicated as the prognosis in such patients is good.

Acute Disease↗
PubMed1992

The Oxford club-foot programme.

We treated 63 club feet in 44 patients by a defined programme of strapping from birth followed by one of two operations performed at six weeks, either a simple calcaneal tendon lengthening or a subtalar realignment, and reviewed them prospectively. The decision as to which operation to perform was taken at four weeks after radiographic measurement of the talocalcaneal angle. All but eight patients (ten feet) were followed for a mean of 8.7 years. The overall results after calcaneal tendon lengthening were satisfactory. The re-operation rate after subtalar realignment was high (39%) due to over or undercorrection of the deformity.

Child↗
PubMed1992

Hip dysplasia in hereditary motor and sensory neuropathies.

Hip dysplasia complicating the hereditary motor and sensory neuropathies is not widely recognised. We describe four patients in whom the neuropathy affected the proximal muscles and we suggest that hereditary motor and sensory neuropathies may be responsible for the failure of the initial treatment of some neonatal dislocated hips.

Adolescent↗
PubMed1992

The ossific nuclei and the cartilage anlage of the talus and calcaneum.

We studied the ossific nuclei on radiographs of the feet of three stillborn infants, two with club feet, relating the size, position and alignment of each nucleus to the cartilaginous talus or calcaneum in which it lay. Anteroposterior projections of the nucleus of the talus show deformity of that bone as well as subtalar malalignment. Lateral projections of the calcaneal nucleus may underestimate the degree of hindfoot equinus.

Calcaneus↗
PubMed1991

Diaphragm paralysis following cardiac surgery: role of phrenic nerve cold injury.

Diaphragm paralysis has been reported radiologically after cardiac surgery with an incidence ranging from 30% to 75% of patients. We studied 100 consecutive patients undergoing open heart operations, half of whom received ice/slush topical hypothermia (group 1) and half of whom did not (group 2). Chest radiology and diaphragm screening were performed at 1 week, 1 month, and every 6 months thereafter in all patients with an elevated diaphragm. Phrenic nerve conduction time was measured in all patients in whom there was radiological evidence of diaphragm paralysis 1 week postoperatively. The two groups were similar in terms of age and sex. Aortic cross-clamp time was less in group 1 (61.5 +/- 15.6 minutes) compared with group II (74.4 +/- 20.8 minutes), although this difference was not significant. Significant differences, however, were found for radiological evidence of partial left lower lobe collapse (82% in group 1 versus 32% in group 2; p less than 0.01) and for radiological evidence of diaphragm paralysis (32% in group 1 versus 2% in group 2; p less than 0.001) within the first postoperative week. Unilateral diaphragm paralysis developed in 16 group 1 patients (15 left sided, 1 right sided) compared with only 1 patient in group 2. In these 16 group 1 patients, diaphragm paralysis was still present in 12 (75%) at 1 month and in 5 (31.3%) at 1 year postoperatively. There were no significant differences between the two groups in terms of postoperative arrhythmias, myocardial infarction, or mortality. Phrenic nerve conduction time was found to be a sensitive indicator of phrenic nerve cold injury and recovery.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Surgical Procedures↗
PubMed1991

Reversible T-wave abnormality in severe acute asthma: an electrocardiographic sign of severity.

Reversible electrocardiographic (ECG) abnormalities are well recognized in severe acute asthma. Inferior lead T-wave abnormalities have only rarely been reported, and their frequency and significance have not been well documented. We studied 70 consecutive patients with severe acute asthma on admission to hospital and during recovery, in order to examine the frequency and natural history of such changes and to document their relationship to the severity of the attack. Twenty-two patients (34%) had inferior lead T-wave inversion on ECGs performed within 1 h of admission (group 1), whereas the rest did not (group 2). Apart from sinus tachycardia this was the most common ECG abnormality. Patients with inferior T-wave inversion were found to have more severe asthma in terms of degree of pulsus paradoxus, peak expiratory flow rate, forced expiratory volume in 1 s and arterial blood oxygen tension. Ten group 1 and ten group 2 patients underwent two-dimensional echocardiography during the acute phase of their illness and during recovery. Six (60%) group 1 patients showed echocardiographic evidence of right ventricular pressure overload compared with only one (10%) patient in group 2 (P less than 0.02). Following recovery, voluntary hyperventilation and exercise testing in ten group 1 patients failed to reproduce the ECG changes seen on admission. Reversible inferior lead T-wave abnormalities may occur in the severe acute asthma and appear to be related to the severity of the attack.

Acute Disease↗
PubMed1991

Bilateral diaphragm paralysis after cardiac surgery with topical hypothermia.

Bilateral diaphragm paralysis is a rare but important complication of open heart surgery. Two cases were found among 360 prospectively studied patients undergoing open heart surgery during one year. Both patients had insulin dependent diabetes with peripheral neuropathy and this may have contributed to their diaphragm paralysis. The patients were studied postoperatively for one year with measurements of lung function, nocturnal oximetry, diaphragmatic function, and phrenic nerve conduction. Treatment with intermittent positive airway pressure ventilation by nasal mask was effective in both patients. After nine months one patient had recovered completely with normal phrenic nerve conduction and diaphragmatic function; the other continues most of his normal daytime activities, but still requires nasal positive airway pressure ventilation for six hours at night.

Cardiac Surgical Procedures↗
PubMed1990

Ultrasound and congenital dislocation of the hip. The importance of dynamic assessment.

One-hundred newborn children at high risk of hip instability were prospectively assessed clinically and by ultrasound. The decision to treat was based only on the clinical examination. At the age of three months all the children were evaluated clinically and with an anteroposterior radiograph of the pelvis. None of the standard ultrasound measurements of acetabular depth and femoral head cover correlated with the outcome at three months. Dynamic assessment of stability was the only ultrasound technique that had a significant relation with outcome.

Female↗
PubMed1989

Diurnal variation in serum cortisol concentrations in asthmatic subjects after allergen inhalation.

To assess whether differences in the adrenal response to allergen are important in determining the magnitude of the allergen induced late responses in asthmatic subjects, we measured serum cortisol concentrations after inhalation challenge with allergen or control solution (phosphate buffered saline). The two challenges were performed in random order with an interval of 14 days. A normal diurnal decrease in serum cortisol concentrations was observed on both days. Mean blood cortisol concentrations three hours after inhalation of allergen (before the late response), nine hours afterwards (at the time of the late response), and 24 hours afterwards were virtually identical to those observed after inhalation of phosphate buffered saline. Serum cortisol concentrations before challenge and three, nine, and 24 hours after challenge were not related to the diurnal increase in blood eosinophils on the control day, or to the size of the late asthmatic response or accompanying changes in blood eosinophils after allergen challenge. It is concluded that serum cortisol concentrations show normal diurnal variation after allergen challenge and are unrelated to the size of the late response or associated changes in blood eosinophil counts.

Adult↗
PubMed1989

Falls in peripheral eosinophil counts parallel the late asthmatic response.

Peripheral eosinophil counts were measured at intervals before and after control and allergen inhalation in 14 asthmatic subjects. A relative fall in eosinophil counts was noted 9 h after allergen challenge, in contrast to the diurnal increase seen on the control day (p = 0.005). This fall in eosinophil count correlated strongly with the magnitude of the late asthmatic response (r = -0.72, p = 0.003) and with the changes in bronchial responsiveness to histamine at 3 and 24 h after allergen was given (r = 0.54, p = 0.044 and r = 0.82, p less than 0.001, respectively). The findings demonstrate eosinophil kinetics are related to the occurrence of late-phase reactions and to the associated worsening of bronchial hyperreactivity.

Adult↗
PubMed1989

Congenital dislocation of the hip presenting after the age of three years. A long-term review.

We reviewed the cases of 38 children with 45 congenitally dislocated hips who presented for primary treatment after the age of three years. Of these, 34 hips were managed by the 'direct approach' of Somerville and Scott (1957); 14 of these required secondary operations for subluxation, often with a poor outcome. Eleven hips were treated by combined pelvic and femoral osteotomy which, in general, gave good results. At a mean follow-up of 16.7 years, 80% of the whole series had a good or excellent clinical result and 51% were good or excellent radiologically. Simultaneous correction both above and below the hip is considered to be the best treatment for the older child with congenital hip dislocation.

Child↗
PubMed1988

Increases in airway responsiveness to histamine precede allergen-induced late asthmatic responses.

Changes in airway responsiveness to histamine after allergen inhalation challenge were studied in 14 nonsmoking atopic adult subjects with asthma. Inhalation challenges with allergen and with phosphate-buffered saline (control challenge) were performed single blind in random order, with an interval of 14 days. The development of a late asthmatic response was accompanied by an increase in airway histamine responsiveness that was significant when it was compared with the airway histamine responsiveness after the control challenge at 3 hours (p less than 0.01), 24 hours (p less than 0.01), and 48 hours (p less than 0.02), with recovery at 2 weeks after allergen inhalation. The 3-hour changes in airway responsiveness occurred independently of changes in airway caliber and correlated with the magnitude of the subsequent late response (r = 0.86; p less than 0.001). These results suggest that the tissue events (possibly airway inflammation) that underlie the late asthmatic response may occur before this response becomes clinically apparent.

Adult↗
PubMed1988

Late femoral osteotomy in congenital dislocation of the hip.

We describe 95 patients with previously treated congenital dislocation of the hip who underwent femoral osteotomy after the age of five years. The commonest indication for surgery was progressive uncovering and subluxation of the femoral head; other reasons were coxa vara, long leg dysplasia and persistent anteversion. Femoral osteotomy for uncovering of the femoral head (Severin Grade III) in this age group gave good results at maturity only when the acetabular angle was less than 25 degrees before operation. Femoral osteotomy alone was inadequate for true subluxation of the hip (Severin Grade IV).

Adolescent↗
PubMed1988

The Oxford Knee for unicompartmental osteoarthritis. The first 103 cases.

The Oxford Knee, a resurfacing prosthesis with a meniscal bearing, can be used for either bicompartmental or unicompartmental arthritis. The first 103 unicompartmental cases are presented at a mean time since operation of 36 months (range 21 to 56 months). In those cases with surviving arthroplasties, pain was relieved in 96%. The full range of pre-operative flexion was maintained and flexion deformity was improved from a mean of 6.7 to 5.4 degrees. Stability and alignment were restored to normal in nearly all the knees. Absence of the anterior cruciate ligament was associated with a significantly greater incidence of failure. Six failures occurred in 37 knees lacking a normal anterior cruciate ligament (16.2%); three occurred in 63 knees with a normal anterior cruciate ligament (4.8%) (p less than 0.02). Criteria for the future selection of patients have been deduced from our experience. The operation is recommended for knees with severe unicompartmental osteoarthritis in which all the ligaments are still intact.

Aged↗