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Biomedical subjects

B Graham

Publications and source records attributed to B Graham.

At least 19 recordsLinked to original sources
PubMed1992

Complications and morbidity of the donor and recipient sites in 123 lateral arm flaps.

The lateral arm flap is a reliable and versatile free tissue transfer. However, the donor and recipient sites may produce an assortment of relatively minor complaints in a large proportion of patients. 109 (89%) out of 123 lateral arm flaps performed over a seven-year period were reviewed an average of three years after surgery. Unsatisfactory appearance of the donor site was noted by 27% of patients and was twice as likely to be reported by female patients and in cases in which the donor site was repaired by a split-thickness skin graft rather than by primary closure. Elbow pain was reported by 19%. Numbness in the forearm was reported by 59% and was unchanged during the follow-up period in the majority of patients. 17% of patients noted hypersensitivity of the donor site to a variety of stimuli such as cold or vibration. Hair formation was reported at the recipient site by 78% of patients. 83% of the patients found the flap to be bulky and 15% had undergone at least one procedure for debulking. We recommend that the use of the lateral arm flap should be limited to males and cases in which the resulting donor site can be closed primarily.

Adolescent↗
PubMed1992

Perineural pressures under the pneumatic tourniquet in the upper extremity.

The literature indicates that tourniquet-induced neurological injuries are relatively common and frequently occur at a subclinical level. In order to evaluate the pressure transmitted to the major peripheral nerves of the arm by an externally applied pneumatic tourniquet, a fully implantable biomedical pressure transducer was placed adjacent the radial, median and ulnar nerves in six cadaver upper extremities of average dimensions. This sensor allowed accurate, reproducible measurements of perineural pressures without requiring significant disruption of the normal anatomical structures of the test limb for its installation. At levels of tourniquet cuff inflation which are commonly used in clinical practice, there was little or no decrease in the pressure detected in the perineural regions over that applied to the surface of the limb. In addition, there was a steep gradient of perineural pressure between locations beneath the edge of the cuff and those under its midpoint. This was most marked at the highest levels of tourniquet inflation. At presently accepted levels of inflation, pneumatic tourniquet cuffs transmit high pressures to the peripheral nerves without any significant attenuation by the intervening soft tissues. The distribution of these forces is one which may subject the underlying nerves to deleterious shear forces, especially at higher levels of inflation.

Arm↗
PubMed1992

Synchronous subungual glomus tumours in adjacent digits.

In the hand, glomus tumours usually present as a single lesion comprising one or more discrete masses affecting the subungual area of one digit. We report a case in which typical glomus tumours occurred simultaneously in the subungual area of two adjacent digits.

Female↗
PubMed1992

Respiratory syncytial virus infection reinforces reflex apnea in young lambs.

To evaluate the effect of respiratory syncytial virus (RSV) infection on reflex apnea elicited by application of water on the laryngeal mucosa, 11 healthy, term lambs were chronically instrumented at 2 wk of age. Six lambs were inoculated with bovine RSV, and five lambs were mock-infected. The lambs were studied awake and unsedated before and 4, 8, 14, and 21 d after infection. RSV infection was associated with slight rhinorrhea and with moderately increased tracheal mucous discharge. There was an average increase of 0.5 degrees C in body temperature. Arterial pH, PO2, and PCO2 remained within the normal range. The ventilatory response to laryngeal chemostimulation measured as the percentage of decrease in ventilation from control was significantly (p less than 0.05) larger among the infected animals when compared with controls on d 4 and 8. There were no differences in indices of respiratory drive (airway occlusion pressure and mean inspiratory flow), ventilatory response to hypoxia (0.10 fraction of inspired O2), or hypercarbia (0.03 fraction of inspired O2). We speculate that RSV infection alters the sensitivity of the laryngeal chemoreceptors so that a prolonged or even fatal apnea may result from stimulation of these receptors. These results may be relevant to the pathogenesis of sudden infant death syndrome associated with RSV infection.

Animals↗
PubMed1990

Withdrawal phenomena after atenolol and bopindolol: hormonal changes in normal volunteers.

1. In order to observe and compare the withdrawal phenomena which follow treatment with the beta-adrenoceptor blocking drugs, bopindolol (with partial agonist activity PAA) and atenolol (without PAA), two groups of six normal volunteers were studied before, during and after 16 days drug administration. 2. Measurements of plasma levels of cortisol, prolactin, insulin, noradrenaline, adrenaline, glucose and potassium were made during a pre-treatment baseline period, on maximum dose and for 21 days after drug withdrawal. Isoprenaline infusions were given to determine sensitivity of heart rate responses and haemodynamic changes measured in response to physiological manoeuvres. 3. Following atenolol withdrawal the results show hormonal evidence of adrenergic overactivity in the form of elevation of plasma cortisol, insulin and glucose levels. After bopindolol withdrawal there was, in contrast, an overshoot of plasma prolactin and a persistent elevation of plasma potassium and adrenaline post-isoprenaline. 4. The hormonal changes which follow withdrawal of atenolol and bopindolol are associated with haemodynamic changes reported elsewhere (Walden et al., 1990). 5. These observations provide confirmatory evidence of a post beta-adrenoceptor blockade withdrawal syndrome which differs between the two drugs studied and this may reflect the properties of the drugs, in particular the PAA of bopindolol.

Adrenergic beta-Antagonists↗
PubMed1990

Withdrawal phenomena after atenolol and bopindolol: haemodynamic responses in healthy volunteers.

1. The effect of withdrawal of atenolol and bopindolol administration was studied in 12 normal volunteers; six on each drug. 2. Following sub-maximal cycle-ergometer exercise training six sets of base-line observations were made of heart-rate (HR) and blood pressure (BP) responses; supine, 60 degrees head-up tilt, during graduated isoprenaline infusion and sub-maximal cycle exercise. 3. The results show that withdrawal phenomena occur following both drug treatments. Atenolol produced a hypersensitivity to isoprenaline and a small overshoot of HR in response to physiological manoeuvres. In contrast bopindolol produced a prolonged state of reduced sensitivity to isoprenaline and some evidence of overshoot of HR with physiological manoeuvres. The differences between the responses may be explained by the different properties of the two beta-adrenoceptor blocking drugs. 4. Some subjects showed clear evidence of overshoot of HR and BP on exercise demonstrating that certain individuals may be more prone to have withdrawal effects than others. 5. The length of time during which withdrawal phenomena can occur is probably longer than has previously been realised. 6. Hormonal changes were found in the withdrawal period (Walden et al., 1990).

Adrenergic beta-Antagonists↗
PubMed1990

Effect of weight cycling on susceptibility to dietary obesity.

Weight cycling, defined as repeated episodes of weight loss followed by weight regain, has been suggested to make rats more energy efficient and produce a state of energy balance favoring accumulation of excess body fat. In addition, weight cycling may favor accumulation of fat in central vs. peripheral adipose depots. In the present study, we gave two groups of female Wistar rats ad libitum access to an obesity-producing high-fat diet (60% of calories from fat). Both groups had previously eaten a low-fat stock diet, but one group had been subjected to three bouts of weight cycling. Rats that were previously weight cycled gained less body weight and body fat when given the high-fat diet than did controls. The lower rate of weight gain was due to a lesser increase in food intake, since daily energy expenditure was significantly lower in previously cycled rats than in controls. In summary, weight cycling does not appear to predispose rats to becoming obese on a high-calorie diet and apparently produces some effect on food intake that reduces, at least in the short run, weight gain on the high-calorie diet.

Adipose Tissue↗
PubMed1990

Metabolic differences between obesity-prone and obesity-resistant rats.

We compared, across several physiological variables, rats most and least susceptible to develop obesity when given a high-fat diet. After 4 wk of eating a high-fat diet (60% of calories from fat), rats in the upper (obesity prone, OP) and lower (obesity resistant, OR) quartiles for weight gain were further studied. OP rats ate significantly more than OR rats, but this did not completely explain differences in their susceptibility to dietary obesity. No differences in 24-h energy expenditure were found between groups. OR rats had a significantly lower 24-h respiratory quotient, indicative of a greater relative proportion of fat oxidation and lower plasma levels of free fatty acids (FFA) than OP rats. Thus the ability to avoid dietary obesity produced by a high-fat diet may depend on an ability to increase fat oxidation in response to increased fat intake. Insulin sensitivity, measured by a euglycemic insulin clamp, was significantly higher in OR than OP rats. We cannot determine from these data whether insulin resistance developed as a consequence of elevated FFA levels or whether the ability to oxidize FFA declined as a result of development of insulin resistance. In summary, we propose that rats able to resist becoming obese on a high-fat diet have the ability to adjust the composition of fuel oxidized to the fuel composition of the diet with a minimum increase in body fat. The specific mechanisms by which this occurs are unknown but may be related to effects of diet on insulin sensitivity.

Animals↗
PubMed1990

Recurrent posttraumatic dislocation of the hip. A report of two cases and review of the literature.

Posttraumatic recurrent posterior hip dislocations were observed in two adult patients. In neither case was there evidence of acetabular dysplasia, paralysis, or infection. In both cases the only significant abnormality discovered was a marked posterior capsular redundancy. In the second case this was clearly shown by a computed tomography (CT) arthrogram. In both instances plication of the posterior capsule prevented further dislocations; however, the second patient developed massive heterotopic ossification around the involved joint and osteonecrosis of the femoral head. Investigation with CT arthrography of patients sustaining one or more dislocations in response to minimal trauma aids in evaluation of capsular abnormalities that may be surgically correctable.

Accidental Falls↗
PubMed1989

OPC-88117 suppresses early and delayed afterdepolarizations and arrhythmias induced by cesium, 4-aminopyridine and digitalis in canine Purkinje fibers and in the canine heart in situ.

The effects of OPC-88117, a new investigational antiarrhythmic drug, on early and delayed afterdepolarizations (EAD and DAD, respectively) were assessed in vitro in canine Purkinje fibers and in vivo in the canine right ventricle. OPC-88117 had similar electrophysiologic properties to class I antiarrhythmic agents in that it decreased Vmax. OPC-88117 decreased the amplitude and prolonged the coupling interval of DAD induced by acetylstrophanthidin. Likewise, OPC-88117 suppressed EAD induced in vitro by 4-aminopyridine. In vivo, cesium-induced EAD, ventricular arrhythmia, and atrioventricular block were suppressed by OPC-88117. In summary, OPC-88117 suppressed DAD and EAD in vitro and inhibited EAD and triggered activity in the in situ canine heart.

4-Aminopyridine↗
PubMed1989

Fractures of the spine in ankylosing spondylitis. Diagnosis, treatment, and complications.

Spinal injuries in patients with previous ankylosing spondylitis were reviewed retrospectively. Fractures frequently occurred as a result of minimal trauma and were associated with severe neurologic deficits in 75% of cases. A characteristic fracture pattern was seen radiographically, and appeared to result from the altered biomechanics of the ankylosed spine. Although the fractures were markedly unstable, nonoperative treatment was uniformly successful in achieving union. The incidence of complications and mortality in this group was significantly lower than that reported in other studies, and the authors attribute this to conservative management within a spinal cord injury unit.

Adult↗
PubMed1989

A systematic evaluation of bathophenanthroline, ferrozine and ferene in an ICSH-based method for the measurement of serum iron.

The chromogenic substrates ferrozine and ferene were compared to bathophenanthroline disulphonic acid for the measurement of iron concentrations in aqueous and serum samples in an assay based on that of the Iron Panel of the International Committee for Standardisation in Haematology. Ferrozine and ferene were more sensitive than bathophenanthroline. Copper at physiological concentrations in plasma caused only minimal positive interference with all three chromogenic substrates when thioglycollic acid was used as the reducing agent, but when ascorbic acid was used significant positive interference occurred with ferrozine and ferene. Interference due to contaminating haem was comparable with all agents. Bilirubin and carotene produced no interference. Profound reductions in colour development were noted with EDTA plasma.

Chromogenic Compounds↗