Internal complementarities in the immune system: regulation of the expression of helper T-cell idiotypes.

More than half of BALB/c helper T lymphocytes specific for 2,4,6-trinitrophenyl (TNP)-modified syngeneic spleen cells are inhibited in their proliferative responses to antigen-presenting cells and in their cooperation with B lymphocytes by monoclonal anti-idiotypic antibodies directed to a TNP-binding BALB/c myeloma protein (MOPC 460). This inhibition is specific for anti-TNP-self helper cells of BALB/c origin and is controlled by IgCh-linked genes, as it is not observed with CB.20 helper cells of the same specificity. In contrast, anti-TNP-self helper cells prepared from BALB/c mice that were chronically suppressed with anti-mu chain antibodies and possessed no B lymphocytes were not inhibited by anti-idiotypic antibodies. We conclude that the B-cell antibody repertoires contribute to the selection of the (idiotypic) T-helper-cell repertoires.     

Sealability of MTA and calcium hydroxidecontaining sealers

Objectives

The aim of this study was to evaluate the apical sealability of Fillapex^®, Endo-CPM-Sealer^® and Sealapex^®.

Material and Methods

Ninety-four freshly extracted single-rooted teeth were selected and decoronated. All teeth were radiographed to confirm the existence of a single and straight root canal, which was prepared using Protaper Universal and 2.5% sodium hypochlorite. The teeth were randomly divided in groups of 10 specimens each according to the sealer, and the canals were filled using the single cone technique and one of the sealers. Four additional teeth were used as controls. The teeth were submitted to dye leakage with Rhodamine B for 24 h but using vacuum on the initial 15 min. Thereafter, they were cut longitudinally and the leakage was measured in a linear fashion from apex to crown. Data were analyzed by ANOVA and Tukey''s tests at 5% significance level.

Results

Fillapex^® and Sealapex^® showed significantly less dye leakage than Endo-CPM-Sealer^® (p<0.05).

Conclusions

It was concluded that Fillapex^® and Sealapex^® were able to prevent apical dye leakage differently from Endo-CPM-Sealer^®.     

Sense of Coherence and Four-Year Caries Incidence in Finnish Adults

This study assesses whether sense of coherence (SOC) predicts incidence of tooth decay over 4 years and the role of dental behaviours in explaining the effect of SOC on incidence of tooth decay. Data from 994 adults who participated in both the Health 2000 survey and the Follow-Up Study of Finnish Adults' Oral Health were analysed for this study. At baseline, participants provided information on demographic characteristics, education level, the SOC scale and dental behaviours (tooth brushing frequency, dental attendance and sugar intake frequency). The 4-year incidence of tooth decay was calculated using data from baseline and follow-up clinical oral examinations. Baseline SOC was significantly related to 4-year incidence of tooth decay after adjustment for demographic factors and education (relative risk: 0.79, 95% CI: 0.63-0.98). This effect was fully attenuated after further adjustment for the three dental behaviours. Tooth brushing frequency and dental attendance were the only dental behaviours significantly related to incidence of tooth decay. This prospective study suggests that SOC predicts incidence of tooth decay and that dental behaviours may help explaining why adults with strong SOC have lower risk of developing tooth decay than those with weak SOC.     

Ejaculation induced by i.c.v. injection of the preferential dopamine D(3) receptor agonist 7-hydroxy-2-(di-N-propylamino)tetralin in anesthetized rats

In addition to serotonin, dopamine within the CNS is known to play a primary role in the control of ejaculation. However, whether D(2) and/or D(3) dopamine receptor subtypes mediate this effect is still unclear. In order to clarify this issue, a pharmacological competitive study using the preferential D(3) agonist 7-hydroxy-2-(di-N-propylamino)tetralin (7-OH-DPAT) alone or in combination with competitive nonpreferential or preferential D(2) and D(3) antagonists delivered intracerebroventricularly (i.c.v.) was undertaken in anesthetized rats. Urethane-anesthetized male rats were implanted into the cerebral ventricle with a cannula for i.c.v. injections, and recording electrodes were placed within the bulbospongiosus (BS) muscle to monitor BS muscle contractions, which were used as a marker for the expulsion phase of ejaculation. Following i.c.v. injection, 7-OH-DPAT induced ejaculation and rhythmic BS muscle contractions. Co-injected i.c.v. with 7-OH-DPAT, the nonselective D(2)/D(3) antagonist (raclopride), and the preferential D(3) antagonist (S(-)-N[n-butyl-2-pyrrolidinyl)methyl]-1-methoxy-4-cyanonaphtalene-2-carboxamide; nafadotride) but not the preferential D(2) antagonist ((+/-)-3-[4-(4-chlorophenyl)-4-hydroxypiperidinyl]methylindole; L 741,626) inhibited the occurrence of ejaculation and BS muscle contractions. These results suggest that i.c.v. delivery of 7-OH-DPAT does represent a pertinent model to investigate the physio-pharmacology of ejaculation. It is inferred that targeting brain D(3) receptors may provide a therapeutic approach for treating ejaculatory disorders in humans.     

Differences in the Spinal Command of Ejaculation in Rapid Ejaculating Rats

IntroductionIt has been hypothesized that lifelong premature ejaculation is part of a biological variation in the intravaginal ejaculation latency, but what causes this variation remains poorly understood.AimThe aim of this study is to elucidate whether variations in ejaculation latencies in an experimental rat model for premature ejaculation are linked to differences in the spinal command of ejaculation.Main Outcome MeasuresElectrical microstimulation of the spinal generator for ejaculation revealed an accelerated expulsion phase in rapid ejaculating rats.MethodsAdult male Wistar rats were categorized as “sluggish,”“normal,” or “rapid” ejaculators on the basis of their ejaculation frequency in sexual mating tests. One to three weeks after selection, males were urethane anesthetized and electrically microstimulated in the spinal generator for ejaculation, evoking ejaculation. Bulbospongiosus muscle electromyographic and intraluminal vas deferens pressure were measured simultaneously, representing, respectively, the expulsion and emission phase in ejaculation.ResultsElectrical microstimulation of the spinal generator for ejaculation evoked ejaculation in “sluggish” (N = 9), “normal” (N = 13), and “rapid” (N = 11) ejaculating rats. Vas deferens contraction (emission phase) was evoked at different stimulation strengths, but response properties were not statistically different between “sluggish,”“normal,” and “rapid” ejaculator rats. Bulbospongiosus muscle contractions (expulsion phase) following microstimulation was significantly accelerated in “rapid” rats as compared with “sluggish” and “normal” rats. The total duration of bulbospongiosus muscle contractions remained unchanged between the three ejaculator groups.ConclusionsOur results provide the first scientific evidence supporting a neurophysiological difference between “rapid,”“normal,” and “sluggish” ejaculators, expressed as an accelerated expulsion phase in “rapid” ejaculator rats. This bridges the gap between a sexual behavior trait and the spinal command of ejaculation. Borgdorff A, Rössler A-S, Clément P, Bernabé J, Alexandre L, and Giuliano F. Differences in the spinal command of ejaculation in rapid ejaculating rats. J Sex Med 2009;6:2197–2205.