Presenting an in vitro cell culture model to determine the cytotoxic effect of benzoyl peroxide vapours.

Benzoyl peroxide (BP) is an initiator of polymerisation used in the synthesis of methyl methacrylate dental materials, and is a known allergen that causes allergic contact dermatitis during occupational exposure, especially in dentists and dental personnel. The eyes of dental technicians, dentists and even patients with an allergic history are the first level of exposure, and therefore complaints of allergic reactions of the eyes are usually noted. In this article the authors used a modification direct cell culture testing method to assess the cytotoxic potential of BP. L929 mouse fibroblasts as well as cells from human limbal eye rings were exposed to BP vapours in the experiments. The MTT and crystal violet assays were also employed to determine cell numbers and viability. Results indicated that there is an exponential decrease in cell viability. After exposure of five minutes, cell viability had already decreased by 20 and 40% for vapours derived from either a 10 or 20 microliters aliquot of BP, respectively. After a further five minutes, cell viability decreased by a further 10% with a statistical difference form the control of p < 0.01. Results indicated that BP vapours are cytotoxic to mouse L929 and human eye fibroblasts. Furthermore, the authors concluded that the permanent L929 mouse fibroblast cell line can provide valuable information regarding the cytotoxic effects of dental products and associated compounds that form toxic vapours.

Anaesthesia and the diabetic patient.

Since it is estimated that 1 out of every 2 diabetic patients will require surgery at some point in his lifetime, it is imperative that the anaesthetist should understand the disease process as well as the anaesthetic problems associated with it. This article emphasizes the medical, surgical and anaesthetic aspects of the treatment of patients with diabetes mellitus.

Methylprednisolone and the adult respiratory distress syndrome.

Total hip replacement was carried out on 22 patients under general anaesthesia. Of these, 10 were pretreated with methylprednisolone (30 mg/kg); 1 of these developed the adult respiratory distress syndrome (ARDS) and had high levels of thromboxane B2 (TXB2) 5 minutes after fixation of the femoral prosthesis and at the end of the operation. The other 12 patients served as controls; 5 of them developed ARDS and had statistically significant higher TXB2 levels than the other 7 control patients who remained well. All patients who did not develop ARDS had low TXB2 levels. TXB2 and beta-thromboglobulin levels followed the same trend and there was good correlation (r=0,6806; P less than 0,01) at the end of the operation in the control group patients who developed ARDS. There was no statistical difference in 6-keto-PGF1 alpha levels between the patients who developed ARDS and those in the control group who remained well. Steroids reduce arachidonic acid metabolism by inhibiting the release of substrate for cyclo-oxygenase and lipoxygenase activity. Patients prone to ARDS thus benefit from methylprednisolone administration.

Anaesthetic management of cerebral artery aneurysms at Tygerberg Hospital, 1980-1982.

Forty-seven patients were operated on for intracranial artery aneurysms at Tygerberg Hospital, Parowvallei, CP, between January 1980 and December 1982. Problems related to anaesthesia which are peculiar to this condition and the solution thereof are outlined. The importance of meticulous anaesthetic management in the successful recovery of these patients, the majority of whom are young and in the productive phase of their lives, is stressed. A plea is made for increased awareness, early diagnosis and surgical intervention to decrease the high mortality rate associated with this lethal condition.

The effect of ventilatory patterns on prostacyclin (PGI2) synthesis in the lung.

Prostacyclin (PGI2) appears to be synthesized in the lungs of man and experimental animals. It has been stated that PGI2 must be regarded as a local hormone that inhibits platelet adhesion to vessel walls only very close to the site of synthesis. The wide range of normal values given for PGI2 may be related to the sensitivity and exclusiveness of the different assay techniques used. In animals hyperventilation increases PGI2 synthesis by the lung, but in agreement with other authors we demonstrated that hyperventilation did not influence PGI2 synthesis in man. We used a radio-immunoassay technique to estimate PGI2 levels.

Early recognition of pulmonary dysfunction during intramedullary orthopaedic surgery.

Peri-operative partial arterial oxygen tension (PaO2) was monitored in 20 patients undergoing total hip replacement. Three distinct groups emerged on analysis of the arterial oxygen tensions. In group I there was no initial decrease in PaO2 but it rose above baseline level towards the end of the procedure. In group II there was a distinct fall in PaO2 during the acetabular and femoral stages of the operation. On termination of the procedure PaO2 had returned to baseline levels. In group III PaO2 values were significantly lower than those in group II during the acetabular and femoral stage s and decreased further at the end of the procedure. One patient in group II and 6 in group III developed postoperative pulmonary dysfunction. A progressive deterioration in PaO2 during hip replacement without recovery at end of the procedure indicates that the patient is likely to develop postoperative pulmonary dysfunction.

[Pheochromocytoma in pregnancy. Anesthetic management of a patient]. / Feochromositoom tydens swangerskap Die narkoschantering van'n pasiënt.

Phaeochromocytoma during pregnancy, although rare, present serious risks to the mother and fetus. An operation was done on a pregnant 19-year-old patient with this condition. The pre-operative preparation and anaesthetic management are discussed.

Should we pre-oxygenate?

The importance of routine pre-oxygenation before induction of anaesthesia was demonstrated in animals. The onset of dangerous levels of hypoxia after the administered of suxamethonium can be delayed considerably by the administration of pure oxygen for 5 minutes before induction. This allows time for an atraumatic and a panic-free intubation before controlled ventilation. After pre-oxygenation the volume of oxygen in the functional residual capacity of the lungs shows a sixfold increase. This is the principal oxygen store during apnoea.

The anthelmintic efficacy of albendazole against gastrointestinal roundworms, tapeworms, lungworms and liverflukes in sheep.

Anthelmintic trials were carried out to evaluate the efficacy of albendazole against helmi of 2,5 to 3,8 mg/kg administered orally, resulted in a 98,8 to 100% reduction of adult parasites of the genera Haemonchus, Ostertagia, Trichostrongylus, Nematodirus, Gaigeria, Oesophagostomum, Chabertia, Marshallagia and Cooperia. Against the immature stages of these genera, except for Marshallagia and Cooperia, which were not tested, a dose level of 2,5 to 3,8 mg/kg was 83,9-100% effective. Albendazole at 2,5 mg/kg was 99,0% effective against adult stages of Dictyocaulus; its activity at a dose of 3,8 mg/kg against the immature stages of D. filaria was 89,3%. In sheep naturally infested with Moniezia, 100% elimination was obtained at a dose level of 2,5 mg/kg. Dose levels of 3,8 mg/kg and higher were more than 76% effective against adult Fasciola hepatica, while a dose of 4,8 mg/kg was 63% effective against adult Fasciola gigantica.

[Malignant hyperthermia in a black child. A case report]. / Maligne hipertermie in 'n Swart kind. 'n Gevalbespreking.

A case of malignant hyperthermia in a Black boy is presented. He developed this condition during repair of a cleft palate, with halothane as the triggering agent. The importance of the high incidence of malignant hyperthermia in patients with certain musculoskeletal abnormalities is stressed. Despite a cool and well air-conditioned theatre, the patient's temperature was 41 degree C when the condition was suspected. At that stage general muscle rigidity was present. The patient was successfully treated with procainamide, sodium bicarbonate and hydrocortisone; surface cooling (with ice packs) was instituted and the stomach was washed out with ice-cold Ringer's solution. Over a period of 14 days serum creatine phosphokinase values decreased from 630 IU (on the day of the incident) to 12 IU. A muscle biopsy showed variation in muscle fibre size. Electron microscopical studies showed myofibrillar disruption and folding of the basement membrane. A modified version of Denborough's technique was used for the in vitro exposure of muscle strips to halothane and suxamethonium. Isometric contraction was measured and recorded. A severe contraction followed the exposure of muscle strips to halothane, which confirmed the diagnosis.

[Aspects of the treatment of postoperative oliguria]. / Aspekte in die behandeling van na-operatiewe oligurie.

The importance and differential diagnosis of postoperative oliguria are discussed. A plea is made for the recognition of undesired postoperative antidiuretic hormone (ADH) secretion as a separate entity in the aetiology of postoperative oliguria. Five patients are described who suffered from postoperative oliguria and in whom the diagnosis of undesired ADH secretion was made. The successful treatment of this condition with diphenylhydantoin is emphasized.

[Operative surgery of giant bilateral bullae of the lungs]. / Die chirurgiese hantering van reuse bilaterale bullae van die longe

Three patients with giant bilateral emphysematous bullae are presented. In each case the bullae occupied a third to half of each hemithorax and the remaining lung tissue was compressed. The most informative pre-operative information was gleaned from the standard chest radiograph. All patients underwent simultaneous bilateral resection of the bullae. There was no mortality and the morbidity was limited. Subjectively all patients improved. Median sternotomy was the approach in one patient and we regard this as an effective approach in cases where bilateral bullae have to be removed.