Case presentation: leukemia in a child

Palsy of the suprascapular nerve may be easily overlooked in the differential diagnosis of the painful shoulder. Although the diagnosis is well documented in the literature, opinion is still divided regarding its etiology and treatment. This case report offers an example of successful nonoperative management of a suprascapular nerve palsy which followed an acute episode of muscular stress in a young male athlete.     

Morphological patterns of paediatric solid cancer in Lagos, Nigeria

With successful implementation of the Expanded Programme on Immunisation (E.P.I.), many Nigerian children are protected against the common infections of childhood which claim their lives within the first decade of existence. Recent observations tend to show that paediatric cancer may start to play a significant role in childhood morbidity and mortality. Therefore, this study analyses 372 cases of paediatric solid malignant tumours received at the Department of Morbid Anatomy, Lagos University Teaching Hospital (L.U.T.H) from 1974 to 1988. Considering all the age groups together, the commonest malignant tumour is lymphoma (32.8%), of which Burkitt's lymphoma accounts for 19.6%. Retinoblastoma and Wilms' tumour represent second and third commonest solid cancers respectively. There is, however, slight variation in the different age groups. For example, in the age group 1-4 years, malignant lymphoma is an uncommon disease representing only 11.0% of all cancers whilst retinoblastoma (34.5%) and nephroblastoma (24.0%) together account for 58.6%. Epithelial cancer although rare in children, represents 12.6% in the 10-14 year age group. There is a higher incidence of this tumour when compared to the other age groups (less than 1 year, 1-4 years and 5-9 years). Intracranial neoplasia are uncommon, representing only 2.0%. The overall incidence of solid malignant tumours in children aged 0-14 years in Lagos is estimated to be 22 per million person years.     

Treatment of hyperkalaemia by altering the transcellular gradient in patients with renal failure: effect of various therapeutic approaches

Ten patients with acute and 60 with chronic renal failure (both groups having hyperkalaemia), were managed at Kenyatta National Hospital in the medical wards and Renal Unit between August, 1995 and January, 1996. They were divided into seven different treatment groups, each consisting of ten patients. Treatment A glucose 25g i.v. with insulin 10 units i.v., treatment B 50 mmol of 8.4% sodium bicarbonate infusion, treatment C 0.5mg of salbutamol i.v. in 50mls 5% dextrose, treatment D was a combination of treatments A and B, treatment E was a combination of treatment B and C, treatment F was a combination of treatments A and C while treatment G was a combination of treatments A and B and C. Serum potassium was measured, 30 minutes, 1 hour, 2 hours, 4 hours and 8 hours after treatment. Plasma glucose concentration was measured before treatment was given and 1 hour after in all patients. Electrocardiography was done before treatment on all patients and repeated 30 minutes and 1 hour after treatment for the patients with hyperkalaemic changes on the initial recording. All treatment modalities had satisfactory potassium lowering effects. Of the single therapeutic approaches, treatment A and C were equieffective, but better than treatment B (P < 0.001). Amongst the two regimen combinations, treatment D and F were more efficacious than treatment E and all the single therapeutic approaches (P < 0.001). Treatment G was the most efficacious in lowering serum potassium in this study. All treatment modalities had maximum serum potassium lowering effect at 1-2 hours. A fall in plasma glucose concentration was a notable feature of treatments A and D, but significant hypoglycaemia occurred in 20% of patients receiving treatment A and in none on treatment D. The ECG changes of hyperkalaemia did not correlate with serum potassium levels. The normalisation of hyperkalaemic ECG alteration occurred within the first 30 minutes after treatment. In conclusion, combination therapies for hyperkalaemia appear to be more efficacious than single therapeutic approaches. Inclusion of salbutamol seems to protect against insulin induced hypoglycaemia. The maximum potassium lowering effect is observed 1-2 hours of administration of either agents. The potassium reducing effect remains significant compared to baseline values even after 8 hours. If dialysis cannot be instituted early enough it seems reasonable to repeat treatment every 4-6 hours to sustain the effect. Repeated administration of glucose with insulin may not be safe because of the hypoglycaemic effect. Other single and combination therapies can theoretically be repeated regularly until dialysis is initiated although this requires further clinical evaluation.     

Sternal wound complications--incidence, microbiology and risk factors

OBJECTIVE: Sternal wound complications, i.e. instability and/or infection (mediastinitis), are important causes of morbidity in patients undergoing cardiac surgery via median sternotomy. Coagulase negative staphylococci, a normal inhabitant of the skin, have evolved as a cause of sternal wound infections. Since these opportunistic pathogens often are multiresistant, they can cause therapeutic problems. METHODS: From 1980 through 1995 open heart surgery, was performed on 13,285 adult patients. Reoperation necessitated by sternal wound complications occurerd in 203 patients (1.5%). The incidence was 1.7% (168/9987) after coronary artery bypass grafting (CABG group) and 0.7% (35/3413) after heart valve surgery with or without concomitant CABG (HVR group). RESULTS: Factors independently related to sternal complications in the CABG group (variable odds ratio [95% C.I.]): year of surgery, 1.9 [1.3-2.8] in 1990-1992, 2.0 [1.4-2.9] in 1993-1995; female sex, 0.4 [0.2-0.6]; diabetic disease, 1.8 [1.2-2.5]; bilateral ITA procedure, 3.3 [1.1-7.7]; and postoperative dialysis, 3.1 [1.4-6.9]. In the HVR group they were: use of ITA graft, 3.7 [1.7-7.7]; early re-exploration because of bleeding 3.0 [1.1-8.2]; and postoperative dialysis 3.1, [1.4-9.3]. Multivariate models were used to compute the risk for sternal complications in each patient. However, the prognostic models based on these risk scores provided low sensitivity and low predictive value. Patients with sternal wound complications showed no increased early mortality but worse long-term survival even after adjustment for other factors (relative hazard in CABG group 1.9 [1.2-2.8]; in HVR group 2.1 [1.1-4.3]. CONCLUSIONS: The use of ITA grafts seems to be one of the most important factors related to sternal wound complications. However, patients at truly increased risk for this complication could not be identified on the basis of the risk factors considered in this study.     

Reduced myocardial Na+, K(+)-pump capacity in congestive heart failure following myocardial infarction in rats

We examined changes in expression and function of the cardiac Na+, K(+)-pump in a post-infarction rat model of hypertrophy and congestive heart failure (CHF). Myocardial infarction was induced by ligation of the left coronary artery in Wistar rats and hearts were obtained from animals with CHF and from sham operated rats after 6 weeks. In the CHF group the ratio of heart weight to body weight was 70% greater compared to sham (*P < 0.05) and all left-ventricular end-diastolic pressures (LVEDP) were above 15 mmHg. The expression of the alpha 1- and beta 1-subunits (mRNA and protein) of the Na+, K(+)-pump was not significantly different in CHF and sham. As compared to sham the alpha 2 isoform, mRNA and protein levels were lower in CHF hearts by 25 and 55%, respectively, whereas the alpha 3 isoform mRNA was greater by 120% in CHF. The alpha 3 protein was not detectable in sham but a prominent band was seen in CHF. Cell volume of isolated cardiomyocytes was 30% larger in CHF. Cardiomyocytes containing the Na+ sensitive fluorescent dye SBFI were loaded to an intracellular Na+ concentration ([Na+]i] of about 140 mM in a K(+)- and Mg(2+)-free medium (140 mM Na+, free Ca2+ of 10(-8) M). To avoid back leak of Na+ and to ensure no voltage effects on the Na+, K(+)-pump extracellular Na+ was subsequently removed, and 6 mM Mg2+ was added to the superfusate, The Na+, K(+)-pump was then reactivated by 10 mM Rb+. SBFI fluorescence ratio decreased mono-exponentially with a time constant (tau) of 191 +/- 15 s in sham (n = 8) and 320 +/- 38 s in CHF (n = 9) rats (P < 0.01). These changes in fluorescence indicate that the maximum rate of decline of [Na+]i from 100 to 35 mM was 39% (P < 0.005) slower in CHF compared to sham, whereas maximum pump rate per cell was not significantly altered (9.0 +/- 0.7 fmol/s in sham and 7.1 +/- 0.7 fmol/s in CHF cells). The [Na+]i which caused 50% pump activation (k0.5) was also not altered in CHF (40 mM in both groups). We conclude that the number of Na+, K(+)-pumps per cell was maintained in CHF but an isoform switch of the alpha 3-replacing the alpha 2-isoform occurred. However, maximum Na+, K(+)-pump rate in terms of rate of change of [Na+]i was significantly attenuated in CHF, most likely as a result of increased cell size.     

Modulation of motor behaviour by NMDA- and cholecystokinin-antagonism

Motor behaviour relies on complex neurochemical interactions in the basal ganglia, in particular the striatum. Antagonistic influences in this region are exerted by afferent projections from, on the one hand, the ventral mesencephalon, utilizing dopamine as a transmitter, and, on the other hand, from the cerebral cortex, signalling by the excitatory amino acid glutamate. The activity in both these neuronal populations appears to be regulated by the neuropeptide cholecystokinin. This article concentrates on interactions between cholecystokinin and glutamate, summarizing some recent morphological, biochemical and behavioural findings. It is suggested that cholecystokinin, acting via the cholecystokininB receptor, potentiates the glutamatergic excitatory input to the striatum.     

Humane and practical implications of using carbon dioxide mixed with oxygen for anesthesia or euthanasia of rats

A series of studies was undertaken to determine whether CO2 can be used as a humane as well as practical agent for euthanasia or anesthesia of rats. Human volunteers rated the degree of discomfort associated with breathing 50 to 100% CO2 mixed with oxygen. Increasing concentrations of CO2 were judged as progressively more noxious, from "highly unpleasant" for 50% CO2 to "painful" for 100% CO2. The practical aspects of anesthesia and euthanasia with 50 to 100% CO2 were studied, using male Sprague Dawley rats. Time to anesthesia and death were inversely related to CO2 concentration, as were the frequency and severity of adverse reactions, including seizures and hemorrhaging from the nose. The severity of edema and hemorrhage, which were observed on histologic examination of the lungs of all rats euthanized with CO2, were greatest in the animals exposed to the lowest concentrations. There were no significant effects of CO2 concentration on time to recumbency or recovery, and there were no significant effects of precharging versus not precharging the chamber on any of the parameters studied. It was concluded that, although CO2 can be used in a humane manner, the concentrations that are least likely to cause pain and distress are associated with the longest times to anesthesia and death, highest incidence of unwanted side effects, and most severe histologic changes in the lungs. Acceptably humane and reasonably practical euthanasia or anesthesia can be achieved using a nonprecharged chamber and a low gas flow rate so that conscious animals are never exposed to CO2 concentrations > 70%.