Regulation of onset of female mating and sex pheromone production by juvenile hormone in Drosophila melanogaster

Juvenile hormone (JH) coordinates timing of female reproductive maturation in most insects. In Drosophila melanogaster, JH plays roles in both mating and egg maturation. However, very little is known about the molecular pathways associated with mating. Our behavioral analysis of females genetically lacking the corpora allata, the glands that produce JH, showed that they were courted less by males and mated later than control females. Application of the JH mimic, methoprene, to the allatectomized females just after eclosion rescued both the male courtship and the mating delay. Our studies of the null mutants of the JH receptors, Methoprene tolerant (Met) and germ cell-expressed (gce), showed that lack of Met in Met²⁷ females delayed the onset of mating, whereas lack of Gce had little effect. The Met²⁷ females were shown to be more attractive but less behaviorally receptive to copulation attempts. The behavioral but not the attractiveness phenotype was rescued by the Met genomic transgene. Analysis of the female cuticular hydrocarbon profiles showed that corpora allata ablation caused a delay in production of the major female-specific sex pheromones (the 7,11-C27 and -C29 dienes) and a change in the cuticular hydrocarbon blend. In the Met²⁷ null mutant, by 48 h, the major C27 diene was greatly increased relative to wild type. In contrast, the gce^2.5k null mutant females were courted similarly to control females despite changes in certain cuticular hydrocarbons. Our findings indicate that JH acts primarily via Met to modulate the timing of onset of female sex pheromone production and mating.All aspects of reproductive maturation in animals including gonad development, pheromone production for communication between the sexes, and mating behavior need to be precisely timed and coordinated to ensure reproductive success, and regulatory hormones are the key to this timing and coordination (1, 2). In most female insects, the sesquiterpenoid juvenile hormone (JH) regulates and coordinates reproductive maturation of the ovaries (2, 3) and often sex pheromone synthesis and mating behavior (4, 5). In Drosophila melanogaster, females are unreceptive to male courtship attempts just after eclosion, but by day 2, most become receptive and mate (6, 7). Implantation of JH-secreting corpora allata (CA) (6) just before eclosion or application of methoprene (8), a JH mimic (JHM), caused females to mate precociously. Decreased JH in the apterous mutant (9) or after treatment of females with precocene, a compound cytotoxic for the CA (10), reduced female mating. These findings suggest that JH may play a role in the maturation of female receptivity in D. melanogaster.The switch from an unreceptive to a receptive state requires coordination of neural activity critical for female mating behaviors with production of sex pheromones that attract the male (11–13). The Drosophila sex pheromones are a subgroup of the cuticular hydrocarbons (CHC) that mediate chemical communication for both sex and species recognition (see refs. 14 and 15 for reviews). In D. melanogaster, two CHCs, (Z,Z)-7,11-C27:2 (C27) and (Z,Z)-7,11-C29:2 (C29) dienes, are female-specific; these dienes are known to play a role in mate choice preference and the onset of male courtship (15–18). Overexpression of the JH esterase-binding protein DmP29 after eclosion, which is thought to reduce the JH titer, caused a reduction in the synthesis of these female-specific dienes (19). The role of JH in the biosynthesis of these CHCs is unknown.In D. melanogaster, there are two basic helix–loop–helix proteins encoded by the paralogous genes, Methoprene-tolerant (Met) and germ cell-expressed (gce), which act as JH receptors in both metamorphosis and reproductive maturation (20–22). Loss of function of both receptor genes is necessary to mimic the effect of genetic ablation of the CA in larvae, which causes prepupal lethality (23–25). In the adult, loss of Met causes both delayed and reduced fecundity, whereas loss of gce has only a slight effect on ovarian maturation (25). To elucidate the molecular mechanisms underlying JH’s role in the onset of mating in D. melanogaster females, we have genetically ablated the CA in the developing adult and found that the onset of mating behavior was delayed, and this delay could be rescued by JH. This action of JH was dependent only on the Met receptor and was partly due to modulation of sex pheromone production.     

The effect of two fibre impregnation methods on the cytotoxicity of a glass and carbon fibre-reinforced acrylic resin denture base material on oral epithelial cells and fibroblasts

Acrylic resin dentures may have cytotoxic effects on oral soft tissues. However, there is sparse data about the cytotoxic effect of fibre-reinforced acrylic resin denture base materials. The purpose of this in vitro study was to determine the effect of two fibre impregnation methods on the cytotoxicity of a glass and carbon fibre-reinforced heat-polymerized acrylic resin denture base material on oral epithelial cells and fibroblasts. One hundred acrylic resin discs were assigned to five experimental groups (n = 20). One of the groups did not include any fibre. Two groups consisted of silane and monomer treated glass fibres (Vetrolex) impregnated into acrylic resin (QC-20) discs. The other two groups consisted of silane and monomer treated carbon fibres (Type Tenox J, HTA). Untreated cell culture was used as positive control. The human oral epithelial cell line and buccal fibroblast cultures were exposed to test specimens. The cytotoxicity of the test materials was determined by succinic dehydrogenase activity (MTT method) after 24 and 72 h exposures. Data were analysed with a statistical software program (SPSSFW, 9.0). A one-way analysis of variance (anova) test and Bonferroni test were used for the comparisons between the groups. All statistical tests were performed at the 0.95 confidence level (P < 0.05). After 24 and 72 h incubation, cell viability percentages of all experimental groups showed significant decrease according to the positive control cell culture. Fibroblastic cell viability percentages of silane and monomer treated fibre-reinforced groups were lower than the unreinforced group. Cell viability of monomer-treated groups displayed the lowest percentages. Elapsed incubation time decreased epithelial cell viability in silane-treated groups. Fibroblastic cell viability was not influenced by elapsed time except the unreinforced group.     

Repeated bevacizumab injections versus mitomycin C in rotational conjunctival flap for prevention of pterygium recurrence

Aims:

To evaluate the efficacy of repeated bevacizumab injection in rotational conjunctival flap surgery versus rotational conjunctival flap with adjunctive mitomycin C (MMC) or rotational conjunctival flap alone.

Materials and Methods:

Ninety eyes of 90 patients who underwent primary pterygium surgery with rotational flap were evaluated. Patients were randomly assigned to undergo conjunctival rotational flap alone (Group A) or conjunctival rotational flap with either 0.02% MMC application (Group B) or adjunctive subconjunctival 2.5 mg/0.1 ml bevacizumab injection (Group C). Each group consisted of 30 eyes. Recurrence rates at 9 months were evaluated.

Results:

There were no statistically significant differences in mean size of the pterygium across the limbus in terms of length (P > 0.5). The recurrence rates at 9 months were 26.6% (n = 8) in Group A, 13.3% (n = 4) in Group B, and 10% (n = 3) in Group C. The recurrence rates in Group B and C were significantly lower than in Group A (P =0.1806). The recurrence rates were similar in Group B and C (P > 0.05).

Conclusions:

Subconjunctival bevacizumab injection may decrease the recurrence rate of primary pterygium surgery with rotational conjunctival flap. Further studies with a larger population and longer follow-up period are needed to supplement this study.     

Effect of magnesium sulphate on bleeding during lumbar discectomy

We assessed the effect of magnesium on the amount of bleeding, coagulation profiles and surgical conditions during lumbar discectomy under general anaesthesia. Forty patients, of ASA physical status 1-2 and aged 18-65 years, undergoing single-level microscopic lumbar discectomy, were randomly assigned to magnesium sulphate (50 mg.kg(-1) in 100 ml saline over 10 min followed by a continuous infusion of 20 mg.kg.h(-1) ) or saline. The mean (SD) estimated blood loss was 190 (95) and 362 (170) ml in the magnesium and saline groups, respectively (mean difference = 172 ml; 95% CI 84-260 ml). The median (IQR [range]) Fromme's scale score for surgical conditions for the magnesium and saline groups were 2 (2-3 [2-3]) and 3 (2-3 [3-4]), respectively (p < 0.05). The bleeding time, haemoglobin, platelet count, prothrombin time, international normalised ratio and fibrinogen levels were similar in the two groups. The activated partial thromboplastin time was prolonged in the magnesium group immediately postoperatively and at 6 h after surgery. After the bolus of magnesium, the heart rate was higher and the mean arterial pressure lower in the magnesium group. The use of magnesium sulphate during lumbar discectomy decreases blood loss, and provides better surgical conditions without marked haemodynamic effects.     

Intraocular pressure in infants and its association with hormonal changes with vaginal birth versus cesarean section

To investigate cord arterial blood sample and the relationship between birth stress and intraocular pressure in infants at 5 min after delivery. The IOP measurements were taken using Tonopen-Avia tonometer to 158 newborns (158 eyes) at 5th min after birth, in a university hospital. Cord blood was collected within 3 min after delivery. Intraocular pressure, gender, gestation period, mode of delivery, and birth weight of newborns were noted from medical records. Sixty-two babies were delivered by normal vaginal delivery (NVD) and 96 by cesarian section (C/S). Mean IOP of NVD and C/S groups were 19.56 ± 3.84 and 17.42 ± 3.50, respectively. There was significant difference of mean IOP between two groups. (p < 0.001) There were significant differences between two groups regarding APGAR score (p < 0.001) and cord blood adrenaline (p = 0.003), noradrenaline (p = 0.008), and cortisol (p < 0.001) levels. There was no difference between infant corneal thickness measurements (p = 0.698). In correlation analyses, there is a strong negative correlation between the labor type and postpartum measurements except corneal thickness. Correlation analyses of the 5th min intraocular pressure of the groups individually revealed significant correlation in the NVD group. The conclusion is that the intraocular pressure of newborn infants was higher in NVD delivery compare to C/S. Blood hormonal changes in different anesthesia types and physical stress was thought as the main reason of this result.     

The effect of photodynamic therapy on retrobulbar blood flow parameters

Purpose: To investigate the effect of photodynamic therapy (PDT) on retrobulbar blood flow parameters. Methods: Twenty‐four patients with choroidal neovascular membrane of at least four MPS disc area in one eye due to age‐related macular degeneration scheduled for PDT were recruited. Peak systolic and end diastolic velocity of ophthalmic, central retinal and posterior ciliary artery of both eyes were measured with colour Doppler imaging and resistivity index were computed before, at the first and fourth weeks following PDT. Results: Following PDT, the mean peak systolic velocity of posterior ciliary artery increased significantly to a value of 31.90 ± 13.44 at the first (P = 0001), then returned to an insignificant value of 29.95 ± 13.03 at the fourth week (P = 0.360), when compared with pre‐PDT mean measurement (30.16 ± 13.15). Resistivity index of posterior ciliary artery also increased significantly to a value of 0.740 ± 0.77 at the first (P = 0.046), then returned to an insignificant value of 0.666 ± 0.14 at the fourth week (P = 0.407), when compared with pre‐PDT mean measurement (0.709 ± 0.90). All the other measured data (peak systolic velocity, end diastolic velocity, resistivity index of ophthalmic and central retinal artery; end diastolic velocity of posterior ciliary artery of the treated eyes; all colour Doppler imaging measurements of untreated eyes) did not show any significant change at the first and fourth week following PDT, when compared with the pre‐PDT values. Conclusion: The peak systolic velocity and resistivity index of the posterior ciliary artery appear to increase in the first week and return to their baseline values at the fourth week following PDT.     

A study of manual toothbrushing skills in children aged 3 to 11 years

The aim of the study was to evaluate toothbrushing management and ability of children in relation to age and gender. The study population consisted of 75 children and were divided into three equal groups as 3-5, 6-8 and 9-11 years of age. The grip type during toothbrushing was recorded on videotape, The most preferred grip types were distal (73%) followed by power (43%) and oblique grips (29%). There were a statistically significant differences between age groups and the grip types (p < 0.0041) but no significant difference was seen between boys and girls in grip preferences (p > 0.05). The mean duration of toothbrushing was shorter in 3-5 years of age group (28 seconds) than the 6-8 and 9-11 age groups (35 and 47 seconds respectively).     

Assessment of atrial conduction time by tissue Doppler echocardiography and P-wave dispersion in patients with mitral annulus calcification

The aim of our study was to investigate atrial conduction time in patients with mitral annulus calcification (MAC) using P-wave dispersion (PWD) and electromechanical coupling measured with the surface electrocardiogram and the tissue Doppler echocardiography. Fifty-nine patients with MAC and 43 control subjects underwent resting the surface electrocardiogram and tissue Doppler echocardiography. The difference between the maximum (Pmax) and minimum P-wave durations was calculated and defined as PWD. Interatrial and intraatrial electromechanical delays were measured with tissue Doppler echocardiography. Both Pmax and PWD were higher in patients with MAC compared with controls (111.4 ± 15.8 vs 97.3 ± 18.8 milliseconds; P < .0001 and 46.4 ± 14.6 vs 31.4 ± 13.1 milliseconds; P < .0001, respectively). Both interatrial and intraatrial conduction time were also delayed in patients with MAC compared with controls (29.8 ± 13.3 vs 17.6 ± 12.5 milliseconds; P < .0001; 9.4 ± 5.1 vs 6.8 ± 4.0 milliseconds; P < .008, respectively). Left atrial (LA) diameter was significantly higher in patients with MAC compared with controls (35.4 ± 5.0 mm vs 32.3 ± 4.2 mm; P < .001). The LA diameter correlated significantly with both interatrial conduction times and PWD (r = 0.56; P < .0001 and r = 0.47; P < .0001, respectively). There is a delay in both intraatrial and interatrial electromechanical coupling intervals in patients with MAC.