Determining the direction of tooth grinding: an in vitro study.

The analysis of microwear patterns, including scratch types and widths, has enabled reconstruction of the dietary habits and lifestyles of prehistoric and modern humans. The aim of this in vitro study was to determine whether an assessment of microwear features of experimental scratches placed on enamel, perpendicularly to the direction of grinding, could predict the grinding direction. Experimental scratches were placed using a scalpel blade on standardised wear facets that had been prepared by wearing opposing enamel surfaces in an electromechanical tooth wear machine. These control 'baseline' facets (with unworn experimental scratches) were subjected to 50 wear cycles, so that differential microwear could be observed on the leading and trailing edges of the 'final' facets. In Group 1 (n=28), the 'footprint' microwear patterns corresponding to the known grinding direction of specimens in the tooth wear machine were identified. Then, they were used to predict the direction of tooth grinding blindly in the same sample after a 2-week intermission period. To avoid overfitting the predictive model, its sensitivity was also cross-validated in a new sample (Group 2, n=14). A crescent-shaped characteristic observed in most experimental scratches matched the grinding direction on all occasions. The best predictor of the direction of grinding was a combined assessment of the leading edge microwear pattern and the crescent characteristic (82.1% in Group 1 and 92.9% in Group 2). In conclusion, a simple scratch test can determine the direction of tooth grinding with high reliability, although further improvement in sensitivity is desirable.

Surgical intervention of intestinal malrotations in paediatric patients without other congenital anatomical abnormalities: overview from a single center.

The subject of malrotation in infants and children without other congenital anatomical abnormalities is reviewed from the perspective of experience with 97 patients operated in 11 years. Fifty-five patients were younger than 6 weeks at operation. They often presented with bilious vomiting, in contrast to older children who presented with non-bilious vomiting or feeding problems. Patients younger than 6 weeks were operated more often acutely than older patients. Volvulus was more common in infants younger than 6 weeks. Two patients with a resulting short bowel syndrome died. In 73 of the surviving 95 (76.8%) children their symptoms disappeared. In the children younger than 6 weeks persisting abdominal problems were significantly less frequent than in older children. In the children presenting with proven gastro-esophageal reflux disease before the malrotation operation, abdominal problems persisted significantly more often. Although there remains considerable controversy over how older children without signs of vascular problems should be managed, failure to respond to radiographic evidence of malrotation could be considered malpractice if volvulus was to occur subsequently. For this reason, every patient with a radiological proven malrotation merits diagnostic laparoscopy.

[Spontaneous rupture of the esophagus (Boerhaave syndrome) in a patient with scleroderma treated by continuous ambulatory peritoneal dialysis]. / Rupture spontanée de l'oesophage (syndrome de Boerhaave) chez une patiente sclérodermique traitée par dialyse péritonéale continue ambulatoire.

Esophageal involvement is a common situation found in 50 to 80% of patients with scleroderma, but Boerhaave's syndrome is rare in this context. The authors report the first case of spontaneous esophageal rupture occurring in a chronic renal failure patient treated by continuous ambulatory peritoneal dialysis. In this observation, sclerodermal esophageal dyskinesia, chronic renal failure which is a classical cause of vomiting and the peritoneal dialysis which play an increasing role in the intraabdominal pressure are potential contributing factors to Boerhave's syndrome. In such patients presenting risk factors, even if they are asymptomatic, it seems reasonable to propose esophageal explorations with manometry or/and endoscopy looking for dyskinesia or other complications of gastro-esophageal reflux.

Cytomegalovirus infection in transplant recipients resolves when circulating gammadelta T lymphocytes expand, suggesting a protective antiviral role.

gammadelta T cells undergo massive expansion in the peripheral blood of renal transplant recipients who are infected with cytomegalovirus (CMV). In a 3-year prospective study, the relationship between the evolution of CMV infection and the kinetics of gammadelta T cell amplification was followed for 10 months after transplantation. Patients with late gammadelta T cell expansion (>/=45 days) had significantly longer (P<.0001) and higher (P<.0003) pp65 antigenemia and more-symptomatic CMV disease than did patients with early expansion. Analysis of data for each patient showed that gammadelta T cell expansion is concomitant with the resolution of CMV infection and disease, regardless of the CMV serologic status of donor and recipient before transplantation. These observations point to gammadelta T cell percentage determination as a new, rapid, and reliable prognosis factor to predict the resolution of CMV infection and strongly suggest that gammadelta T cells play a protective role against CMV infection.

Major expansion of gammadelta T lymphocytes following cytomegalovirus infection in kidney allograft recipients.

In normal persons, circulating gammadelta T cells comprise a minor cell subset (0.5%-6% of total lymphocytes). gammadelta T cells were studied in the context of therapeutic immunosuppression in transplanted patients. Flow cytometry detected an expansion of gammadelta T cells in 31 of 205 renal allograft recipients and in 2 of 41 uremic patients but in none of 45 healthy subjects. Univariate statistical analysis identified cytomegalovirus (CMV) infection (P<. 001), second graft (P<.001), and antithymocyte globulin treatment (P=.01) as three variables associated with high levels (>=6%) of circulating gammadelta T cells in allograft recipients. Multivariate analysis further indicated that CMV infection was the only independent parameter associated with >6% gammadelta T cells. gammadelta T cell expansion directly followed CMV infection and was never observed in persons who did not develop CMV infection. Thus gammadelta T cells may represent a first-line defense mechanism against CMV infection in a person whose alphabeta T cell response has been weakened by immunosuppression.