Comparison of the flexural strength of two dual cure adhesive resin cements under oral simulated conditions: an in-vitro study.

The purpose of this in vitro study was to evaluate the flexural strength of the newly developed self-adhesive dual cure resin cement and compare it with conventional resin cement under oral simulated conditions. A conventional resin cement (Calibra) and self adhesive resin cement (RelyX U100) were selected and 40 specimens of each cement were fabricated for the study. Half of these specimens were polymerized directly whereas the other half were polymerized through 2 mm of porcelain disc. Specimens were tested after 24hrs and after 30 days immersion in artificial saliva. A three point bending test was performed using universal testing machine at a crosshead speed of 1mm/min. Overall RelyX U100 showed higher mean flexural strength compared to Calibra (141.55 MPa, 119.46MPa, respectively). When the specimens of both the cements were light cured through 2 mm porcelain disc, their flexural strength decreased significantly. The mean flexural strength of both self adhesive and conventional dual cure adhesive resin cements was increased significantly after storage in artificial saliva for 30 days at 37 degreeC. Among the two dual cure resin cements, the self adhesive dual cure cement (RelyX U100) showed increased overall mean flexural strength as compared to conventional resin cement (Calibra) under all the curing and storage protocols.

In silico screening of the juvabione category of juvenile hormone analogues with juvenile hormone binding protein of Galleria mellonella--a docking study.

Juvabione, dehydrojuvabione and their aromatic analogues act as juvenile hormone mimics against diverse strains of insect species. Large numbers of modified juvenoids containing the juvabione skeleton, with various structural variations, are synthesized. Some of these compounds exhibit a very high degree of juvenile hormone activity and are presently in use. In this paper we report a comparative molecular docking study of synthesized juvabione, natural juvenile hormone III and synthetic insect growth regulators (fenoxycarb, S-21149, Compound 1, pyriproxyfen) with the juvenile hormone binding protein of Galleria mellonella. The study clearly indicates a higher binding affinity of nitro-substituted juvabione over natural juvenile hormone III and synthetic insect growth regulators such as fenoxycarb and S-21149.

Complete nucleotide sequence of cherry virus A (CVA) infecting sweet cherry in India.

Cherry virus A (CVA) is a graft-transmissible member of the genus Capillovirus that infects different stone fruits. Sweet cherry (Prunus avium L; family Rosaceae) is an important deciduous temperate fruit crop in the Western Himalayan region of India. In order to determine the health status of cherry plantations and the incidence of the virus in India, cherry orchards in the states of Jammu and Kashmir (J&K) and Himachal Pradesh (H.P.) were surveyed during the months of May and September 2009. The incidence of CVA was found to be 28 and 13% from J&K and H.P., respectively, by RT-PCR. In order to characterize the virus at the molecular level, the complete genome was amplified by RT-PCR using specific primers. The amplicon of about 7.4 kb was sequenced and was found to be 7,379 bp long, with sequence specificity to CVA. The genome organization was similar to that of isolates characterized earlier, coding for two ORFs, in which ORF 2 is nested in ORF1. The complete sequence was 81 and 84% similar to that of the type isolate at the nucleotide and amino acid level, respectively, with 5' and 3' UTRs of 54 and 299 nucleotides, respectively. This is the first report of the complete nucleotide sequence of cherry virus A infecting sweet cherry in India.

Free volume study on calcification process in an intraocular lens after cataract surgery.

An opacified intraocular lens explanted from a patient in the postoperative period after phacoemulsification was investigated to find the cause of opacification. From the UV-visible and energy dispersive X-ray spectroscopy (EDS) measurements, the opacification in the present case seems to be due to calcification of the intraocular lens and not due to modification in the UV absorber material of the lens. The average free volume size of the intraocular lens both in unimplanted and explanted state were obtained from positron lifetime spectroscopy (PLS). Further, the combined FTIR and PLS results indicate that calcium gets into the free volume cavities of the intraocular lens matrix as a cationic moiety, may be in the form of Ca(++). The small decrease in glass transition temperature of the calcified lens seems to indicate the plasticizing action of calcium ions. The present results could be of some use in the design of the intraocular lens material in which calcification would be minimum.

Frozen sperm as an alternative to shipping live mice.

Dissemination of live mice by air and/or ground shipping is costly and can result in spread of disease between senders' and recipients' colonies. Transporting cryopreserved sperm that can be recovered and used for deriving live mice by using assisted reproductive techniques may be a more economical, efficient, and safer alternative to shipping live animals. In this study, we tested the hypothesis that sperm cryopreserved at one location and then transported transcontinentally via a common package delivery service using both air and ground transport to a second location could be recovered for in vitro fertilization (IVF) to successfully derive liveborn offspring at the second location. Split aliquots of sperm from individual mice were tested at both senders' and recipients' locations by using similar cryopreservation and IVF procedures, in order to control for differences in handling procedures. At both senders' locations, fertilization rates using cryopreserved sperm were lower than those using fresh sperm. However, fertilization rates using sperm recovered after cryopreservation at the senders' locations were not significantly different than those obtained when the same cryopreserved sperm was recovered and used at the recipients' locations. At the one location where tested, the numbers of pups born and subsequently weaned after IVF using either shipped or nonshipped cryopreserved sperm were similar. We conclude that cryopreserved sperm can be transported between different facilities and used for IVF to successfully derive liveborn mice.

Effect of oophorectomy on expression of calcium sensing receptor mRNA in rat duodenal mucosa.

Calcium sensing receptor (CaR) in duodenal mucosa may be involved in active calcium absorption. Estrogen deficiency results in decreased intestinal calcium absorption. Effects of bilateral oophorectomy (OVX) have been studied on calcium homeostasis, bone mineral density (BMD) and CaR mRNA levels in duodenal mucosa at 4 weeks in adult female Sprague Dawley rats and compared with those in sham-operated and control group. There was no significant change in serum corrected calcium, inorganic phosphorous, calcidiol and intact parathyroid hormone in all the three groups. OVX rats had a significant decline in serum estrogen (E2) levels and alkaline phosphatase. They also had a significant decrease in BMD (DXA) at lumbar spine in vivo, and proximal and distal tibia in vitro while there was no significant change in serum E2 and BMD parameters in sham-operated and control rats. Northern blot analysis revealed no significant change in the CaR mRNA expression in duodenal mucosa in all three groups. The results suggests that CaR mRNA expression in duodenal mucosa is not affected by physiological circulating concentrations of estradiol in rats.

Short-term androgen deprivation does not alter CaR and VDR mRNA expression in duodenal mucosa in male rats.

Androgen deprivation is associated with decline in intestinal calcium absorption. The effect of androgen on CaR and VDR intestinal mucosa has not yet been studied. Calcium homeostasis, a real bone mineral density (aBMD, dual energy X-ray absorptiometry) and expression of CaR and VDR mRNA in duodenal mucosa of orchidectomized (ORX) and sham operated (Sham) adult Sprague Dawley rats at 4 week have been studied. There was no significant difference in serum calcium, alkaline phosphatase, calcidiol and calcitriol levels between both the groups. Serum testosterone (T) (ng/dl) and inorganic phosphorous (iP) (mg/dl) levels were significantly lower in ORX rats. As compared to sham rats, ORX rats had significant decline in in-vitro aBMD at proximal, middle and distal tibia, proximal, mid and distal femur and femoral neck (P < 0.05). Northern blot analysis revealed no significant alteration in the CaR and VDR mRNA expression in duodenal mucosa in ORX rats. CaR and VDR mRNA expression in duodenal mucosa is therefore, not affected by physiological concentrations of testosterone in rats.

CLINICO-RADIOGRAPHIC EVALUATION OF XENOGRAFTS IN MAXILLOFACIAL SURGERY.

An endeavour to find a suitable substitute for autogenous bone graft in corrections of maxillofacial deformities has been going on. Evaluation of commercially processed xenograft (SURGIBONE) has been carried out as a substitute for autogenous grafts in various maxillofacial surgical procedures in the Department of Dental Surgery at Armed Forces Medical College. Clinical and radiographic evaluation in 15 patients revealed highly satisfactory result with complete integration of the graft without any adverse host tissue reaction within the follow-up period lasting from 12-18 months.

EFFICACY OF INDIGENOUSLY MANUFACTURED TITANIUM BONE PLATES AND SCREWS IN MAXILLOFACIAL SURGERY.

Titanium plates and screws (implants) developed indigenously by DRDO were used to manage 20 patients with maxillofacial fractures. Efficacy of these implants was evaluated clinically and radiographically so that these can be put into use on routine basis. In 18 patients recovery was uneventful. Extended maxillomandibullar fixation was employed for 3 to 7 days only depending on the degree and displacement of fractures and; mobilisation of jaw was allowed fully from 7th post operative day onwards. 2 patients developed discharging sinus at the fractured mandibular angle region which was due to impacted mandibular third molar in the line of fracture. This healed completely after extraction of offending tooth and appropriate medication. There was no occlusal or nerve disturbances, wound dehiscence or rejection of the bone implant. Radiographical evaluation at various intervals showed good alignment, approximation and sound healing of fractured fragments, with complete osteointegration.

OSSEOINTEGRATED TITANIUM PLASMA COATED IMPLANTS IN RECONSTRUCTION OF EDENTULOUS MANDIBLE.

Fifteen patients underwent surgical insertion of titanium plasma sprayed screws in the mandible ridge over the symphysis region. In 3 patients, along with the screws in the symphysis region, hollow basket implant type 'H', one each in the mandible first/second molar region were inserted. Implants were fixed only in those patients who had retention and stability problems of mandibular artificial denture. Indication, technique and biocompatibility of titanium implants and tissue supported over denture have been discussed.

Effects of oral lithium on the action of various C.N.S. active drugs.

Effects of prolonged lithium administration was seen on the action of various psychoactive drugs in animals. Apomorphine induced pecking in pigeons increased significantly by lithium treatment for 14 days, from 1445.3 +/- 202.5 in control to 2785.8 +/- 205.8 in Gp. B. Haloperidol-induced catalepsy score in albino rats increased significantly following chronic lithium treatment compared to control. Chlorpromazine-induced hypothermia in rabbits was immediate but transient, while in lithium treated rabbits induction of hypothermia was delayed, sustained and of greater magnitude. This action of lithium may be mediated by increasing the permeability of blood-brain barrier, or enhancing the sensitivity of alpha-adrenoceptors in brain.

Regulation of cholinomimetic action of pyrantel pamoate by calcium channels in Setaria cervi.

Nerve muscle preparation of Setaria cervi (Nematoda:Filarioidea) exhibits spontaneous rhythmical movements when suspended in isolated organ bath containing modified Ringer's solution. Pyrantel pamoate (50 ng/ml) when applied caused initial short lasting stimulation followed by irreversible paralysis. When suspended in calcium free bathing fluid the movements of n.m. preparation showed a gradual decrease both in amplitude and rate of contraction til the movements ceased completely. The effect was similar when EDTA was added to the bath fluid. The stimulant effect of Pyrantel pamoate was blocked in calcium free solution and in bath applied EDTA. Calcium channel blocker Nifedipine in a concentration of 500 ng/ml blocked the effect of Pyrantel pamoate (50 ng/ml). Neither stimulation nor depression of movements was evident with higher concentration of PP (250 mg/ml) the stimulant effect of Pyrantel pamoate was blocked while the depressant effect characterized by decrease in amplitude of calcium is essential for the stimulant effect of Pyrantel pamoate and its response on n.m. preparation is similar to Acetylcholine.

Identification of voltage-sensitive calcium channels in Setaria cervi (Nematoda: Filarioidea) and their role in regulation of spontaneous motility.

Whole worm of Setaria cervi and its nerve muscle preparation exhibit rhythmical movements when suspended in modified Ringer's solution in an isolated organ bath. Deprivation of calcium from the bathing fluid results in gradual reduction in the amplitude and rate of contraction till the movements ceased completely. Similar results were obtained by adding EDTA (5 micrograms/ml) to the bath. The effect was concentration related and was evident early with higher concentration of EDTA. Acetylcholine which increases spontaneous movements of the whole worm as well as N.M. preparation failed to do so when the movements were inhibited either in calcium free solution or in the presence of EDTA. Addition of calcium channel blocker, Nifedipine to the bathing fluid also resulted in concentration related reduction of movements of the preparation of Setaria. Further, the stimulant response of Ach was also reduced by Nifedipine and this too was related to the concentration of calcium channel blocker in the bath. The evidence clearly indicates that presence of calcium is essential for the stimulant response of Ach on S. cervi, which like mammalian tissues contain calcium channels that can be blocked by specific blocking agents.