Formate-producing capacity provided by reducing ability of Streptococcus thermophilus nicotinamide adenine dinucleotide oxidase determines yogurt acidification rate.

Yogurt is made by fermenting milk with 2 lactic acid bacteria, Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus. To comprehensively understand the protocooperation mechanism between S. thermophilus and L. bulgaricus in yogurt fermentation, we examined 24 combinations of cocultures comprising 7 fast- or slow-acidifying S. thermophilus strains with 6 fast- or slow-acidifying L. bulgaricus strains. Furthermore, 3 NADH oxidase (Nox)-deficient mutants (Δnox) and one pyruvate formate-lyase deficient mutant (ΔpflB) of S. thermophilus were used to evaluate the factor that determines the acidification rate of S. thermophilus. The results revealed that the acidification rate of S. thermophilus monoculture determined the yogurt fermentation rates, despite the coexistence of L. bulgaricus, whose acidification rate was either fast or slow. Significant correlation was found between the acidification rate of S. thermophilus monoculture and the amount of formate production. Result using ΔpflB showed that the formate was indispensable for the acidification of S. thermophilus. Moreover, results of the Δnox experiments revealed that formate production required Nox activity, which not only regulated dissolved oxygen, but also the redox potential. The Nox provided the large decrease in redox potential required by pyruvate formate-lyase to produce formate. A highly significant correlation was found between formate accumulation and Nox activity in S. thermophilus. In conclusion, the formate production ability provided by the action of Nox activity determines the acidification rate of S. thermophilus, and consequently, regulates yogurt coculture fermentation.

Bonding abutments to cast metal post/cores: comparison of pre-treatment effects.

Bond strengths were evaluated for (1) metal primer systems when the metal was contaminated by a dentin conditioner and (2) a dentin adhesive system when dentin was contaminated by metal primers. Disc specimens were cast in a silver-palladium-copper-gold (Ag-Pd-Cu-Au) alloy and dentin specimens were prepared by grinding the labial surface of bovine teeth. Specimens were treated with (1) metal primer alone, (2) dentin conditioner alone, (3) metal primer followed by dentin conditioner and (4) dentin conditioner followed by metal primer. A resin cement was poured into a mould over a restricted bonding area and allowed to set. Metal specimens were shear stressed to failure after thermocycling (4-60 degrees C; 20,000 cycles). Dentin specimens were stressed in the same manner after 24 h of immersion in 37 degrees C water. The results were compiled and analysed by anova. Data for dentin specimens treated with dentin conditioner only or with the combination of dentin conditioner and metal primer were not significantly different, statistically. Post-thermocycled groups indicated that bond strengths to the alloy significantly decreased (P < 0.05) when the primed metal surface was contaminated with dentin conditioner regardless of the timing of its application.

Giant hepatic granuloma caused by Bartonella henselae.

We report a 10-year-old girl with a 3.0- by 3.5-cm giant hepatic granuloma caused by Bartonella henselae. Such a solitary and large granuloma associated with B. henselae infection has not been previously reported. We believe that B. henselae infection is a consideration in the differential diagnosis of a large hepatic mass.

[Three children with systemic cat scratch disease].

Three girls with systemic cat scratch disease, aged 10, 13 and 9 years, were reported. They presented a prolonged fever and back pain in the early stage of the disease, and had no regional lymphadenopathy. Two of them had hepatosplenic granulomas, one with multiple 5 mm hypoechoic lesions in the liver and spleen, and the other with a single 2.5 cm hypodense lesion in the left hepatic lobe. The latter patient underwent a partial left hepatic lobectomy. All patients had elevated titers of antibodies to Bartonella henselae. Polymerase chain reaction detected B. henselae DNA in tissue specimens of the patient who underwent a hepatic lobectomy. Cat scratch disease should be recognized as a cause of fever of unknown origin because the prevalence of B henselae infection might be higher in Japan.

Congenital heart defects in Sotos sequence.

Of 10 patients with typical Sotos sequence, 5 had various congenital heart defects. They included 2 patients with secundum atrial septal defect, and one patient each with patent ductus arteriosus with mitral valve regurgitation, tricuspid atresia plus pulmonary atresia, and ventricular septal defect. Increases of head circumference and weight gain were less accelerated in the patients with congenital heart defects than in those without heart defects, while growth in length was comparable between the 2 groups. In view of these findings, it is suggested that the rate of congenital heart defects in patients with Sotos sequence is much higher than that reported in the literature.

XY and XX complete moles: clinical and morphologic correlations.

The results of clinical, morphologic, and histologic analysis of nine XY complete moles (six karyotyped, three Y-chromatin positive) were compared with the results from analysis of 16 XX moles. Five of the nine XY moles were proved to result from dispermy while all the 16 XX moles studied originated from the doubling of a haploid sperm. At follow-up delayed decrease or rebound of urinary (or serum) human chorionic gonadotropin levels was noted in three of eight women with XY moles and in five of 15 women with XX moles. One woman with an XY mole was treated for lung metastasis, but her condition remained stable over a 4-year follow-up period. No appreciable difference was noted in the gross and microscopic findings between the XY and XX moles. On the other hand, differences were noted between younger (12 weeks or less of menstrual age) and older (13 weeks or more) moles. Younger moles had smaller, elliptic or club-shaped villi with numerous secondary villous sprouts, poorly demarcated central cisternae, and frequent mesenchymal capillaries. Older moles had larger, oval or globular villi with sparse villous sprouts, well-developed central cisternae, and less frequent remnants of capillaries. Trophoblastic hyperplasia was more marked in older than in younger moles.