Association of black-pigmented bacteria with endodontic infections.

Black-pigmented bacteria (BPB) have been associated with endodontic infections. The purpose of this study was to evaluate further the presence of BPB with the clinical signs and symptoms associated with endodontic infections. Microbial samples were collected from the root canals of 40 intact teeth with necrotic pulps and apical periodontitis. Conventional laboratory methods were used for identification of the strains of BPB isolated in pure culture. In addition, the polymerase chain reaction and specific primers for 16S r-RNA genes were used to differentiate Prevotella nigrescens from Prevotella intermedia. Twenty-two (55%) samples were positive for the growth of BPB. Of those, 11 of 22 (50%) were identified as P. nigrescens, 8 of 22 (36%) were P. intermedia, 2 of 22 (9%) were Porphyromonas gingivalis, and 1 of 22 (5%) was Prevotella melaninogenica. Sixteen of the 22 root canals positive for the growth of BPB were associated with purulent drainage either from the root canal or an associated sinus tract. Statistical analysis did not show a significant relationship for the presence of BPB with clinical signs and symptoms.

Black-pigmented bacteria in coronal and apical segments of infected root canals.

Black-pigmented bacteria (BPB) have been associated with infections of endodontic origin. The purpose of this study was to culture and identify BPB from the apical and coronal segments of infected root canals to understand better their ecological relationships. Teeth with a periapical radiolucency were extracted and immediately placed in reduced transport fluid for transport to an anaerobic chamber. Of 18 sampled roots, 12 were positive for the growth of BPB. Eight of the 12 roots with BPB had a carious exposure of the pulp chamber. Seven roots had Prevotella nigrescens in both the apical and the coronal segments. Six of these seven teeth had carious exposures of the pulp chamber. Of the 12 roots infected with BPB, six roots had two different species of BPB, with P. nigrescens always being one of the species. P. nigrescens was the most often isolated BPB from both the coronal and apical segments of infected root canals.

Initial resistance of Mycobacterium tuberculosis in Northern Nigeria.

Of 61 isolates of Mycobacterium tuberculosis form patients in northernn Nigeria denying any previous treatment for tuberculosis 7 (11.5 per cent) yielded resistant cultures. Four (6.6 per cent) were resistant to isoniazid, 2 (3.3 per cent) to PAS (1 also to thiacetazone), and 1 (1.6 per cent) to streptomycin. No mycobacteria other than M. tuberculosis were isolated from these patients. These results suggest that the level of initial drug resistance in northernn Nigeria may be lower than that found in other African countries.

Poisoning by bites of the saw-scaled or carpet viper (Echis carinatus) in Nigeria.

The Saw-scaled or Carpet Viper (Echis carinatus) whose range extends from Senegal to Bengal probably bites and kills more people than any other species of snake. One hundred and fifteen patients with poisoning caused by its bite were studied in the savanna region of Nigeria, where victims of this snake may occupy 10 per cent of hospital beds. Patients showing no signs of envenoming were excluded. All patients had local swelling at the site of the bite. Other features included local blistering (13 per cent), local necrosis (11 per cent), incoagulable blood (93 per cent), and spontaneous systemic bleeding (57 per cent). There was evidence of disseminated intravascular coagulation in all cases; fibrinogen was severely depleted, fibrin degradation products were increased (mean 1711 +/- 904 micron per ml), but significant thrombocytopenia (less than 103 000 per mm3) was seen in only ten severe cases. Clotting factors V, VIII, II and XIII were depleted, while X and VII were usually normal. Fibrinolytic activity was rarely increased, so it seems likely that a procoagulant action (direct activation of prothrombin) is principal effect of E. carinatus venom on blood coagulation in man. Development of the haemostatic defect was observed as early as 75 minutes and as late as 27 hours after the bite. Spontaneous haemorrhage is clinically the most important effect of E. carinatus venom, causing the five deaths in this series. The relative importance of procoagulant and haemorrhagic components of the venom in causing haemorrhage is discussed. Complement activation via the classical and alternative pathways may have contributed to vascular damage. Mortality was reduced from the untreated level of between 10 and 20 per cent to 2.8 per cent in a group of 107 patients treated with 10 to 110 ml of specific antivenom. The dose was controlled using a simple clotting test. Blood coagulability was restored in two to 39 (mean 12) hours after the first dose of antivenom. Immediate-type serum reactions were observed in 21 per cent of cases. Additional treatment included blood transfusion for patients in haemorrhagic shock and ealry surgical débridement of necrotic tissue at the site of the bite.

Radar and optical measurements of C2n.

Comparison is made of C(2)(n) profile measurements obtained with a stellar scintillometer and uhf 440-MHz radar. The scintillometer C(2)(n) was obtained at altitude positions between 5 and 18 km, each with a broad height resolution. The radar C(2)(n) was obtained at 400-m intervals with 550-m height resolution. The radar C(2)(n) measurements, when smoothed with the scintillometer weighting function, are in good agreement with the scintillometer C(2)(n) measurements.

Bites by the saw-scaled or carpet viper (Echis carinatus): trial of two specific antivenoms.

Echis carinatus is the most important cause of morbidity and mortality from snake bite in Nigeria and in many other parts of the world. Forty-six patients with systemic poisoning by this snake were given echis antivenom made either by the South African Institute for Medical Research (S.A.I.M.R.) or by Behringwerke (North and West African polyvalent antivenom). A simple test of blood coagulability was used to assess whether an adequate neutralizing dose of antivenom had been given. An average of 15.2 ml S.A.I.M.R. antivenom restored normal coagulability permanently in all 23 patients in one group, but in the other group receiving an average dose of 37.9 ml Behringwerke antivenom normal clotting resulted in only 18 out of 23 patients. Local tissue swelling was similar in both groups, but local necrosis occurred in three patients treated with Behringwerke antivenom and in none given S.A.I.M.R. antivenom.

Silicosis among grindstone cutters in the north of Nigeria.

Many of the grindstones used in Nigerian homes are quarried from sandstone in a small group of villages near Kano in the extreme north of the country. Of an unselected group of 126 stonecutters from two of these villages 49 were found to have radiographic evidence of silicosis, with progressive massive fibrosis in 17. Those with silicosis had worked longer in the quarries than 77 whose radiographs showed no evidence of silicosis. Sixty-three per cent of the silicotics had respiratory symptoms, the commonest being breathlessness on moderate exertion. Cough was the earliest symptom in 42%. Only 35% had abnormal physical signs in the cardiorespiratory system, 18% had clearly reduced ventilatory capacity, and airways obstruction was evident in 16%. The prevalence of silicosis in these open-cast sandstone quarriers is unexpectedly high. This is probably explained by the intensity of exposure and the particular kind of sandstone being worked. Reduction of dust exposure in these quarries raises severe practical problems, but the inhabitants of this drought-ridden area can scarcely be expected to abandon their traditional livelihood.