Origin of synaptic noise.

The poison from puffer fish, tetrodotoxin, was applied to the kitten spinal cord. This application greatly reduced the synaptic noise recorded from lumbar motoneurons. The noise is largely evoked by nerve impulses.

Comparison of human serum, parotid and mixed saliva levels of phenoxymethylpenicillin, ampicillin, cloxacillin and cephalexin.

1. A study has been made of serum, mixed and parotid salivary levels attained in normal volunteers following oral dosage of 500 mg phenoxymethylpenicillin tablets, 500 mg crushed phenoxymethylpenicillin tablets in capsules, 500 mg ampicillin, 500 mg cloxacillin and 500 mg cephalexin.2. High mixed saliva levels were obtained with phenoxymethylpenicillin tablets and it is considered that these were due to rapid intra-oral dissolution of surface powder from friable tablets. No saliva levels were detected when tablets from the same batch were put into capsules.3. Low or no saliva levels were achieved with ampicillin, cloxacillin and cephalexin.4. The mode of action of antibiotics in oral infections is discussed.

Control of epidemic group A meningococcal meningitis in Nepal.

During the first six months of 1983, an epidemic of serogroup A meningococcal meningitis occurred in the Kathmandu valley of Nepal, resulting in 875 cases and 95 deaths. The annual attack rate was 103 cases per 100,000 population, with a peak attack rate occurring in April. Epidemic meningococcal disease had not been recognized previously in Nepal. Early in 1984, a review of hospital-based data on pyogenic meningitis in Kathmandu showed three times as many cases per month compared with the same period the previous year, suggesting that a recurrent epidemic was unfolding. Beginning in February 1984, a vaccination campaign directed at a high-risk target population of people aged 1-24 years was launched; over 329,000 doses of bivalent A/C meningococcal vaccine were given, achieving approximately 64% coverage of the target population. A dramatic decline in the number of new meningitis cases occurred coincident with the initiation of the mass vaccination campaign. This experience demonstrates that it is possible, with appropriate surveillance efforts, to detect an evolving epidemic of meningococcal disease early in its course and to institute control measures in advance of the expected epidemic peak.

Miniplate removal in trauma and orthognathic surgery--a retrospective study.

Records of patients undergoing the surgical removal of miniplates placed during the management of maxillofacial trauma (n=49) and orthognathic surgery (n=16) in a single unit, over a 2-year period have been analysed. Data concerning indications for plating, age and sex distribution, site of plating, time between insertion and removal, antibiotic prophylaxis, general medical factors and clinical indications for plate removal were evaluated for all patients. In addition, data for trauma patients included the site of fracture, and time delay between injury and plate insertion. Infection and/or wound dehiscence were the predominant causes for plate removal in both groups, in spite of the routine use of prophylactic antibiotics in a predominantly young, healthy cohort of patients.A removal rate of approximately 10% was found in the two groups of patients. This low rate would seem to imply that the routine removal of miniplates is not clinically indicated.

Intraoral actinomycosis. Report of five cases.

Five intraoral presentations of actinomycetes are recorded, in three of which the infection was almost certainly specifically due to the microorganisms. The importance of careful histopathologic examination is underlined, and the failure in some cases to investigate apparently simple infections bacteriologically is highlighted.

The microbiology of periapical granulomas.

Of the 16 periapical granulomas studied, 14 (88%) yielded a positive growth when homogenized and cultured. The concentration of colony-forming units per milliliter of the suspension ranged from 10(1.3) to 10(4.0) (mean 10(2.2)). A total of 47 isolates comprising 26 (55%) facultative anaerobes and 21 (45%) strict anaerobes were obtained. The organisms most commonly cultured were Veillonella species (15%), Streptococcus milleri (11%), Streptococcus sanguis (11%), Actinomyces naeslundii (11%), Propionibacterium acnes (11%), and Bacteroides species (10%). Most of the organisms (96%) were sensitive to either amoxicillin, clindamycin, or tetracycline, whereas only 45% were sensitive to metronidazole.

Staphylococcal sub-mandibular lymphadenitis in childhood.

Thirteen cases of staphylococcal sub-mandibular lymphadenitis in children are presented and the diagnosis and treatment are discussed. All but one of the strains of Staphylococcus aureus isolated were resistant to penicillin, while the converse was true for erythromycin. Epidemic strains of Staphylococcus aureus were not found when bacteriophage typing was carried out on isolates from seven of the 13 patients.

Cervico-facial and intra-oral actinomycosis: a 5-year retrospective study.

Actinomycosis is often considered to be a rare disease in the oral region. A retrospective study of the Routine Diagnostic Services in Glasgow Dental Hospital revealed 39 cases in which actinomyces were detected, indicating that this organism is not infrequent in oral infections and may be seen in a variety of lesions.

Presynaptic inhibition evoked by muscle contraction.

1. Contractions of flexor and extensor muscles of the knee and ankle were used to investigate presynaptic inhibition at the spinal level.2. Contractions evoked dorsal root potentials, and increased the excitability of the central terminals of group Ia, Ib and low threshold cutaneous primary afferent fibres.3. The monosynaptic reflexes recorded in response to stimulation of flexor or extensor muscle nerves were depressed, in the presence of strychnine hydrochloride 0.1 mg/kg I.V., by the contractions.4. It is suggested that these presynaptic inhibitory effects are largely due to the activation of Golgi tendon organs by contraction.

First-time coronary artery bypass grafting: the anaesthetist as a risk factor.

We have investigated the contribution of the anaesthetist and surgeon to outcome after 1301 consecutive coronary artery bypass grafting operations (first operation). The mean + 1 SD aspartate amino transferase concentration on the day after surgery (AST-D1) was 134 u litre-1 (or, after logarithmic transformation, 94 u litre-1). Twenty patients were selected at random from each of three groups having AST-D1 less than 100 u litre-1, 100-134 u litre-1 or greater than 134 u litre-1; positive ECG diagnoses of perioperative myocardial infarction were significantly more frequent with AST-D1 values greater than 100 u litre-1 than with smaller values, but no more frequent with AST-D1 greater than 134 u litre-1. Because several deaths occurred before AST-D1 could be measured, an "adverse outcome" was defined as either hospital death or AST-D1 greater than 100 u litre-1. Univariate analysis implicated both anaesthetist and surgeon as significant predictors of adverse outcome but, after allowing for 12 patient-related factors, only cardiopulmonary bypass time (or ischaemic cross-clamp time) (P less than 0.01) and anaesthetist (P = 0.05) were associated significantly with outcome.