The influence of thread geometry on biomechanical load transfer to bone: A finite element analysis comparing two implant thread designs.

BACKGROUND: The success of dental implants depends on the manner in which stresses are transferred to the surrounding bone. An important consideration is to design an implant with a geometry that will minimize the peak bone stresses caused by standard loading. The aim of this study was to assess the influence of implant thread geometry on biomechanical load transfer and to compare the difference between two different thread designs. MATERIALS AND METHODS: A three-dimensional finite element model of D2 bone representing mandibular premolar region was constructed. Two implants of differing thread geometries, 13-mm length, and 4-mm diameter along with superstructures were simulated. One design featured fourfold microthread of 0.4-mm pitch, 0.25-mm depth in the crestal one-third; 0.8-mm pitch, 0.5-mm depth in the apical two-third. The other design had a single-pitch microthread of 0.8-mm pitch, 0.25-mm depth in the crestal one-third; 0.8-mm pitch, 0.5-mm depth in the apical two-third. A static axial load of 100-N was applied to the occlusal surface of the prosthesis. ANSYS CLASSIC 9.0 (PA,USA)software was used for stress analysis as von Mises stresses. RESULTS: A comparison of von Mises stresses between two thread designs revealed that fourfold microthread allows better stress distribution within the implant body by 43.85%, abutment by 15.68%, its superstructure by 39.70% and 36.30% within cancellous bone as compared to single-pitch microthread. The effective stress transfer to the cortical bone is lowered by 60.47% with single-pitch microthread. CONCLUSION: Single-pitch microthread dissipates lesser stresses to cortical bone while the implant body, abutment, and superstructure absorb more stress. This will have a positive influence on the bone-implant contact and contribute to preservation of crestal bone. Implant with single pitch microthread will thus be preferable to be used in areas where the amount of cortical bone available is less.

A study on the determination of risk factors associated with babesiosis and prevalence of Babesia sp., by PCR amplification, in small ruminants from Southern Punjab (Pakistan).

Babesiosis is a parasitic infection due to the multiplication of tick borne parasite, Babesia sp., in erythrocytes of host, which includes a wide variety of vertebrates including small ruminants causing decreased livestock output and hence economic losses. The objective of the present study was to establish a PCR based method for the detection of Babesia sp. in small ruminant population in Southern Punjab and to determine the risk factors involve in the spread of babesiosis. A total of 107 blood samples were collected from 40 sheep and 67 goats in seven districts of Southern Punjab from randomly selected herds. Data on the characteristics of the animals and the herd were collected through questionnaires. 36 blood samples (34% of total) produced the DNA fragment specific for 18S rRNA gene of Babesia sp., by PCR amplification, of which 20 were sheep and 16 were goats. Samples from all seven district contained Babesia positive samples and prevalence varied between 18 to 68%. It was observed that male animals (P = 0.009) and young animals under one year of age (P = 0.01) were more prone to the parasite. It was observed that herds consist of more than 15 animals (P = 0.007), composed of mixed species of small ruminants (P = 0.022), associated with dogs (P = 0.003) and dogs having ticks on their bodies (P = 0.011) were among the major risk factors for the spread of babesiosis in small ruminants.

A study on the prevalence of a tick-transmitted pathogen, Theileria annulata, and hematological profile of cattle from Southern Punjab (Pakistan).

The present study was carried out to determine the prevalence of Theileria annulata in large ruminants in Southern Punjab (Pakistan). Blood samples were collected from 144 large ruminants, consisting of 105 cattle and 39 buffaloes, from six districts of Southern Punjab including Multan, Layyah, Muzaffar Garh, Bhakar, Bahawalnagar, and Vehari. Data on the characteristics of the animals and herds were collected through questionnaires. The age of animals (P = 0.02), presence of ticks on animals (P = 0.02), and presence of ticks on dogs associated with herds (P = 0.05) were among the major risk factors involved in the spread of tropical theileriosis in the study area. Two different parasite detection techniques, PCR amplification and screening of Giemsa-stained slides, were compared, and it was found that PCR amplification is a more sensitive tool (19% parasite detection) as compared to smear scanning (3% parasite detection) for the detection of T. annulata. Twenty eight out of 144 animals produced the 721-bp fragment specific for T. annulata from five out of six sampling districts. Different blood (hemoglobin, glucose) and serum (ALT, AST, LDH, cholesterol) parameters of calves and cattle were measured and compared between parasite-positive and parasite-negative samples to assess the effect of T. annulata on the blood and serological profile of infected animals.

Método de cromatografía líquida de alto rendimiento para la cuantificación de duloxetina en plasma de ratas / High-performance liquid chromatography method for the quantifi cation of duloxetine in rat plasma

Se desarrolló un método HPLC selectivo y sensible para la cuantificación de duloxetina en plasma de ratas. Se utilizó trifluoperacina como estándar interno (IS). El presente método utilizó la precipitación de proteínas para la extracción del fármaco del plasma de las ratas. La separación y cuantificación se realizaron en modo isocrático utilizando como fase móvil tampón fosfato de 25 mM (pH 3,0)/acetonitrilo (60:40, % v/v) y en fase reversa una columna fenil C18 (250 mm x 4,6 mm, 5µ). El efluente de la columna se monitorizó con un detector UV a 217 nm. Este método fue lineal en el intervalo 44 – 2816,00 ng/ml con un coeficiente de regresión superior a 0,99. La recuperación media de duloxetina e IS fue 82,33 ± 2,10 y 75,37 ± 1,07, respectivamente y el método fue exacto, preciso y específi co durante el estudio. Este método validado es sensible y reproducible y puede utilizarse para estudios farmacocinéticos (AU)

A sensitive and selective HPLC method was developed for quantification of duloxetine, in rat plasma. Trifluoperazine was used as an internal standard (IS). The present method used protein precipitation for extraction of the drug from rat plasma. Separation and quantification was carried using in isocratic mode using 25 mM phosphate buffer (pH 3.0)/acetonitrile (60:40, % v/v) as mobile phase and on reverse-phase C18 phenyl column (250 mm x 4.6 mm, 5µ) and the column effluent was monitored by UV detector at 217 nm. This method was linear over the range of 44 - 2816.00 ng/ml with regression coefficient greater than 0.99. The mean recovery of duloxetine and IS were 82.33 ± 2.10 and 75.37 ± 1.07, respectively and the method was found to be precise, accurate and specific during the study. This validated method is sensitive and reproducible and it can be used for pharmacokinetic studies (AU)

Spectrofluorimetric method for determination of duloxetine hydrochloride in bulk and pharmaceutical dosage forms.

A simple accurate, sensitive and reproducible spectrofluorimetric method was developed for the analysis of duloxetine hydrochloride in pure and pharmaceutical dosage form. Duloxetine hydrochloride showed strong native fluorescence in 0.05 M acetic acid having excitation at 225 nm and emission at 340 nm. Effect of different solvents were thoroughly investigated. The calibration graph was linear in the range from 0.020 to 0.400 mug/ml. The proposed method was statistically validated and successfully applied for analysis of capsule dosage forms. The limit of detection and limit of quantification were found to be 0.003 mug/ml and 0.010 mug/ml, respectively. The percentage recovery was found to be in the range of 98.71% to 99.17%.