Double-dissociation of D1 and opioid receptor antagonism effects on the acquisition of sucrose-conditioned flavor preferences in BALB/c and SWR mice

Sugar appetite is influenced by unlearned attractions to sweet taste and learned responses to sugars' taste and post-ingestive actions. In rats, sugar-conditioned flavor preferences (CFP) are attenuated by dopamine D1 (SCH23390: SCH), but not by opioid (naltrexone: NTX), receptor antagonism. Sucrose-CFP occurs in BALB/c and SWR inbred mice that differ in their suppressive effects of SCH and NTX on sucrose intake. The present study examined whether SCH and NTX altered expression of previously learned sucrose-CFP and acquisition (learning) of sucrose-CFP in these strains. In Experiment 1, food-restricted mice were trained (10 one-bottle sessions) to drink a more-preferred flavored (e.g., cherry) 16% sucrose solution (CS +/Sucrose) on odd-numbered days, and a less-preferred flavored (e.g., grape) 0.05% saccharin solution (CS −/Saccharin) on even-numbered days. Two-bottle tests with the flavors mixed in 0.2% saccharin occurred 30 min following vehicle (Veh), SCH (50-800 nmol/kg) or NTX (1-5 mg/kg) assessing preference expression. CS + preference expression in BALB/c and SWR mice following Veh were significantly reduced by SCH and NTX. In Experiment 2, separate groups of BALB/c and SWR mice received Veh, SCH (50 nmol/kg) or NTX (1 mg/kg) injections 30 min prior to daily one-bottle training sessions with the CS +/Sucrose and CS −/Saccharin solutions assessing preference acquisition. Subsequent two-bottle tests with the CS + vs. CS − solutions were conducted without injections. CS +/Sucrose training intakes were reduced by SCH in both strains and by NTX in BALB/c mice. In the initial two-bottle test, sucrose-CFP acquisition was significantly reduced in BALB NTX (54%), but not in BALB SCH (77%) groups relative to the BALB Veh group (85%). In contrast, sucrose-CFP acquisition was significantly reduced in SWR SCH (61%), but not in SWR NTX (83%) groups relative to the SWR Veh group (86%). DA D1 and opioid receptor signaling modulate acquisition and/or expression of sucrose-CFP in mice with significant strain differences observed.     

Novel drugs from marine microorganisms

Marine microorganisms have expected mounting consideration on the basis of bioactive metabolites and propose an exclusive prospect to both enhance the amount of aquatic natural foodstuffs in clinical trials as well as speed up their progress. This review focuses particularly on those molecules, originated from marine microorganisms, presently in the medical pipeline that have been recognized or highly expected to be identified based on growing incidental evidence. Particularly karlotoxin class compounds, isolated from dinoflagellate Karlodinium veneficum, offer chances to create new molecules for control of cancer and high serum cholesterol levels.     

Antihypertensive effect of <Emphasis Type="Italic">Melothria maderaspatana</Emphasis> leaf fractions on DOCA-salt-induced hypertensive rats and identification of compounds by GC–MS analysis

The present study was designed to investigate the antihypertensive effect of Melothria maderaspatana leaf fractions on deoxycorticosterone acetate (DOCA)-salt-induced hypertensive rats and to identify compounds from the active fraction by GC–MS analysis. Administration of DOCA salt significantly increased the systolic and diastolic blood pressure compared to sham-operated control rats. When treated with chloroform (CFM), ethyl acetate (EAFM) or methanol fractions of M. maderaspatana (MFM), EAFM alone significantly lowered the systolic and diastolic blood pressure. The levels of magnesium and copper significantly increased in plasma and decreased in tissues while the zinc level significantly increased in plasma and tissues, and administration of EAFM brought these parameters back to sham-operated control levels. By GC–MS analysis, phytochemicals such as coumarin, vallinic acid, p-coumaric acid, gallic acid, caffeic acid, and ferulic acid were identified in EAFM. In conclusion, the EAFM controls blood pressure in DOCA-salt hypertensive rats and reverts the metabolic alterations in magnesium, copper and zinc.     

Protective effect of Melothria maderaspatana leaf fraction on electrolytes, catecholamines, endothelial nitric oxide synthase and endothelin-1 peptide in uninephrectomized deoxycorticosterone acetate–salt hypertensive rats

This study was designed to investigate the protective effect of ethyl acetate fraction of Melothria maderaspatana (EAFM) leaf on electrolytes, catecholamines, endothelial nitric oxide synthase (eNOS) and endothelin-1 (ET-1) peptide in uninephrectomized deoxycorticosterone acetate (DOCA)-salt hypertensive rats. Administration of DOCA-salt significantly increased the systolic and diastolic blood pressure and treatment with EAFM significantly lowered the blood pressure. In DOCA-salt rats, the levels of sodium and chloride increased significantly while potassium level decreased and administration of EAFM brought these parameters to normality. The levels of epinephrine and norepinephrine increased significantly in DOCA-salt rats and administration of EAFM significantly decreased these parameters to normality. DOCA-salt hypertensive rats exhibited significantly decreased L: -arginine and nitrite + nitrate levels and administration of EAFM brought these parameters to normality. DOA-salt hypertensive rats showed down-regulation of eNOS and up-regulation of ET-1 protein expressions in heart and kidney, and treatment with EAFM prevented down-regulation of eNOS and significantly down-regulated the ET-1 protein expressions. In conclusion, EAFM provides good blood pressure control by enhancing potassium and decreasing sodium levels, decreasing levels of epinephrine and norepinephrine, and preventing down-regulation of eNOS and significantly down-regulating ET-1 protein expression.     

The effect of thermocycling on the bonding of different restorative materials to access opening through porcelain fused to metal restorations

PURPOSE

Porcelain fused to metal (PFM) crowns provide the best treatment option for teeth that have a large or defective restoration. More than 20% of teeth with PFM crowns or bridges require non-surgical root canal treatment (NSRCT). This may be due to the effect of restorative procedures and the possible leakage of bacteria and or their by-products, which leads to the demise of the tooth pulp. Thus, this study was planned to compare the ability of the restorative materials to seal perforated PFM specimens.

MATERIALS AND METHODS

The study evaluates the ability of amalgam, composite or compomer restorative materials to close perforated PFM specimen''s in-vitro. Ninety PFM specimens were constructed using Ni-Cr alloys and feldspathic porcelain, and then they were divided into 3 groups: amalgam (A), composite + Exite adhesive bond (B) and compomer + Syntac adhesive bond (C). All the PFM samples were embedded in an acrylic block to provide complete sealing of the hole from the bottom side. After the aging period, each group was further divided into 3 equal subgroups according to the thermocycling period (one week for 70 cycles, one month for 300 cycles and three months for 900 cycles). Each subgroup was put into containers containing dye (Pelikan INK), one maintained at 5℃ and the other at 55℃, each cycle for 30 sec time. The data obtained was analyzed by SPSS, 2006 using one way ANOVA test and student t-test and significant difference level at (P<.01).

RESULTS

The depth of dye penetration was measured at the interfaces of PFM and filling materials using Co-ordinate Vernier Microscope. The lowest levels of the dye penetration for the three groups, as well as subgroups were during the first week. The values of dye leakage had significantly increased by time intervals in subgroups A and C.

CONCLUSION

It was seen that amalgam showed higher leakage than composite while compomer showed the lowest level of leakage.     

In vitro assessment of strength, fatigue durability, and disassembly of Ti6Al4V and CoCrMo necks in modular total hip replacements

Modularity in total hip replacement offers advantages with regard to biomechanical adjustments and leg lengths. Recently, modular femoral necks were introduced as an added advantage to head modularity permitting further adjustments in femoral version as well as offset and ease of revision. Currently, most necks are made of Ti6Al4V for which cases of in vivo fractures and inseparable neck-stem junctions have been reported. Therefore, we investigated CoCrMo head-Ti6Al4V stem hip replacements with necks made of CoCrMo as an alternative to Ti6Al4V. We compared the two materials with respect to (1) compressive load bearing capacity; (2) fatigue durability; and (3) component distraction. We performed in vitro fatigue-pull-off, microscopy, fatigue durability and compression investigations. The CoCrMo neck showed a load bearing capacity of 18 kN, 38% higher than 13 kN for the Ti6Al4V neck. A fatigue load of 11.2 kN for 1 million cycle failure was achieved with CoCrMo translating into nearly 1000 times longer fatigue life compared to Ti6Al4V necks. The neck-stem distraction force showed large statistical variation and was similar for both neck materials. Overall, the results suggest a superiority of CoCrMo over Ti6Al4V as neck material with regard to mechanical behavior. However, the corrosion behavior was not appropriately assessed and necessitates additional investigations.