An outbreak of group B streptococcus infection in a neonatal nursery and subsequent trial for prophylaxis of nosocomial transmission

An outbreak of sepsis and meningitis caused by group B streptococcus occurred in three very low birthweight infants. To prevent further nosocomial transmission, immune globulin and ampicillin sodium were administered intravenously to other very low birthweight infants. After this prophylaxis, no other infants were involved in this outbreak. Immuno- and chemoprophylaxis may be considered as procedures to prevent nosocomial infection for very low birthweight infants.     

A Transarterial Approach of Electrical Ablation of Atrioventricular Junction in a Dog Model: Comparison of the Effects between High and Low Energy Shocks

To analyze the effectiveness of a transarterial catheter technique for electrical ablation of the atrioventricular junction, 30 mongrel dogs were studied by means of synchronized electrical shock between the catheter adjacent to the noncoronary cusp and a metal plate behind the dog's back using a standard cardioversion unit. These dogs were classified into two groups according to the energy delivered. The high energy group received more than 100 joules (group A) and the low energy group received from 20 to 60 joules (group B). Complete atrioventricular block was induced by a single shock in all dogs. In group A, ventricular premature beats appeared in all dogs; ventricular fibrillation and ventricular tachycardia appeared immediately in half (6/12) after electrical ablation. No ventricular dysrhythmias occurred in group B. Temporary right ventricular pacing was also performed in 10 out of 12 dogs in group A after electrical ablation. In contrast only one dog required pacing in group B. The cycle length of the subsidiary pacemaker rhythm was essentially identical in both groups. The QRS duration of the subsidiary pacemaker rhythm in group A was significantly longer in group B (P less than 0.01). The extent of myocardial damage induced by electrical ablation in group B was more localized than those in group A. However, the histological lesion representing the granulation tissue with necrosis and slight chronic inflammatory cell infiltration, was identical between both groups A and B. It was concluded that this technique of low energy electrical ablation of the atrioventricular junction adjacent to the noncoronary cusp via a transarterial approach was useful in producing an experimental model of chronic complete AV block.     

Endotoxin affects the expansion modes of liver macrophages after partial hepatectomy

We studied the effect of increased endotoxin levels on the expansion modes of liver macrophages after two-thirds partial hepatectomy using anti-endotoxin polymyxin B. The expansion consists of dual modes: local proliferation and immigration. Local proliferation of mature cells was evaluated by the S-phase proportion measured by flow cytometric DNA analysis. This proportion (11.8 +/- 1.3% before hepatectomy) decreased to 6.0 +/- 1.1% at 12 h and reached a maximum of 21.9 +/- 2.7% on the 5th day after hepatectomy. In polymyxin B treated rats, the proportion reached a maximum of 21.1 +/- 1.6% at 48 h without any preceding decrease. Immigration of macrophage precursors was evaluated by the decreasing proportion of latex beads-containing cells that were marked as resident liver macrophages by injection of latex beads before hepatectomy. This proportion (98.7 +/- 0.2% before hepatectomy) was significantly decreased to 90.5 +/- 1.6% at 48 h. In polymyxin B treated rats, however, the proportion showed no significant decrease within 3 days. These results indicate that endogenous endotoxin, which suppresses the local proliferation and promotes extrahepatic recruitment, regulates the number of liver macrophages in regenerating rat liver.     

Surgical Strategy for Directional Deep Brain Stimulation

Deep brain stimulation (DBS) is a well-established treatment for drug-resistant involuntary movements. However, the conventional quadripole cylindrical lead creates electrical fields in all directions, and the resulting spread to adjacent eloquent structures may induce unintended effects. Novel directional leads have therefore been designed to allow directional stimulation (DS). Directional leads have the advantage of widening the therapeutic window (TW), compensating for slight misplacement of the lead and requiring less electrical power to provide the same effect as a cylindrical lead. Conversely, the increase in the number of contacts from four to eight and the addition of directional elements has made stimulation programming more complex. For these reasons, new treatment strategies are required to allow effective directional DBS. During lead implantation, the directional segment should be placed in a “sweet spot,” and the orientation of the directional segment is important for programming. Trial-and-error testing of a large number of contacts is unnecessary, and efficient and systematic execution of the programmed procedure is desirable. Recent improvements in imaging technologies have enabled image-guided programming. In the future, optimal stimulations are expected to be programmed by directional recording of local field potentials.     

Risk factors affecting third molar autotransplantation in males: a retrospective survey in dental clinics

Summary The aim of this study was to investigate the risk factors affecting long‐term prognosis of autotransplantation of third molars with complete root formation in males at dental clinics. Participating dentists were requested to provide information on transplantations they had undertaken from 1 January 1990 to 31 December 2010. Data on a total of 708 teeth from 637 patients were collected. After data screening and elimination, participants of this study consisted of 183 teeth of 171 males ranging from 20 to 72 years of age (mean age, 44·8 years). The cumulative survival rate was 86·0% at the 5‐year mark, 59·1% at 10 years and 28·0% at 15 years. The mean survival time was 134·5 months, as calculated by the Kaplan–Meier method. Single factor analysis using the log‐rank test showed that the following factors had significant influence (P < 0·05) on survival of transplanted teeth: periodontal disease as the reason for recipient site tooth extraction, fewer than 25 present teeth and Eichner index Groups B1 to C. Cox regression analysis examined five factors: age, smoking habit, recipient site extraction caused by periodontal disease, fewer than 25 present teeth and Eichner index. This analysis showed that two of these factors were significant: fewer than 25 present teeth was 2·63 (95% CI, 1·03–6·69) and recipient site extraction caused by periodontal disease was 3·80 (95% CI, 1·61–9·01). The results of this study suggest that long‐term survival of transplanted teeth in males is influenced not only by oral bacterium but also by occlusal status.     

Lichen planus-like contact dermatitis due to methacrylic acid esters

Summary We report a patient who had lichen planus-like lesions on sites repeatedly exposed to methacrylic acid esters used in the car industry. Histologically, the lesions showed all the features of classical lichen planus. Patch testing revealed positive reactions to methacrylic acid esters in concentrations as low as 5 × 10⁻³%. As dental devices contain methacrylic acid esters, it is possible to speculate that methacrylic acid esters may be one of the causative agents for oral lichen planus.