Recent advances in polymer drug conjugates.

Polymer drug conjugates play an important role in the delivery of drugs. In the polymeric drug conjugates, the bioactive agent is combined covalently with polymer to achieve the efficient delivery of bioactive agents in the required or specific period of time along with the enhancement of permeability and retention time. A large number of biodegradable polymers have been widely used in the area of biomedical science. Among them, polyphosphazene, is a biodegradable polymer having versatile nature because of its two chlorine atoms attached on both sides of phosphorus atom of its polymeric backbone, it can be easily replaced by nucleophilic substitution reaction. A plenty of work has been explored for its biomedical applications such as tissue engineering, vaccine drug delivery, polyphosphazene- anticancer drug conjugates with doxorubicin, paclitaxel, platinum complexes, methotrexate and gemcitabine for the targeted drug delivery etc. This review is focused on the recent advances in the biomedical applications of polyphosphazene-drug conjugates.

Mapping QTLs for popping ability in a popcorn x flint corn cross.

Popping expansion volume (PEV) in popcorn (Zea mays L.) is a distinct heritable character and defined as the ratio of the volume after popping to the volume before popping. PEV is quantitatively inherited and 3-4 genes/quantitative trait loci (QTLs) have been implicated. In the present study, we have dissected the quantitative PEV into two component traits, viz., flake volume (FV) and percent unpopped kernels (UPK), and mapped QTLs using SSR markers for all three traits with 194 F3 families derived from a popcorn (A-1-6) x flint corn (V273) cross. Heritability (broad sense) estimates for PEV, FV and UPK based on F3 mean bases were 0.72, 0.54 and 0.68, respectively. The QTL analyses for the three traits based on combined environment data were performed by composite interval mapping using QTL cartographer. Four QTLs were identified for PEV on chromosomes 1, 3, 8 and 10, which together explained 62% of the phenotypic variance (sigma2p). Four QTLs were found on chromosomes 1, 5, 9 and 10 for FV (explaining 44% of sigma2p) and five QTLs for UPK on chromosomes 1, 3, 4, 5 and 9 (explaining 57% of sigma2p). The relative efficiency estimates of marker-based selection in comparison to phenotypic selection for PEV (1.10), FV (1.22) and UPK (1.11) indicated that marker-based selection could be relatively more efficient. The QTL on chromosome 1S for PEV was found to be most significant, where QTLs for hard endosperm starch concentration had been detected earlier.

Dorsal placement of the pedicled preputial/penile onlay flap for anterior urethral stricture: is it more logical?

OBJECTIVES: We present our preliminary experience in the management of inflammatory anterior urethral strictures with a dorsally/dorsolaterally placed penile/preputial vascularized flap and discuss the distinct advantages of this procedure over a traditional ventrally placed flap. METHODS: Twelve patients (age, 20-66 years; mean age, 40.5 years) with recurrent inflammatory strictures of the penile and/or bulbar urethra (penile, 2; bulbar, 5 and bulbopenile, 5) were treated with dorsally/dorsolaterally placed penile/preputial (penile skin, 5; prepuce, 7) vascularized flap substitution urethroplasty. Prior to surgery, 7 patients had suprapubic cystostomy for acute urinary retention and 5 had a mean peak flow rate of 6.2 ml/sec. Inferior pubectomy was performed as an adjunct in two patients to facilitate proximal placement of the flap. Follow-up (5 to 24 months; mean, 15.5) included uroflowmetry and retrograde urethrograms at 6, 12 and 18 months, and thereafter as required. RESULTS: The mean stricture length was 5.8 cm (range, 3 to 12 cm) and all strictures were associated with dense spongifibrosis. Temporary urethral fistulae, which healed spontaneously, occurred in 4 patients. The clinical and radiological outcome during the mean follow up of 15.5 months was gratifying. The mean peak flow rate improved to 24.2 ml/sec. No stricture recurrence has been noted to date. Sacculation of the flap, diverticulum formation and post-void dribble have not been encountered. None of the patients developed chordee or erectile dysfunction. CONCLUSIONS: Dorsal onlay preputial/penile flap urethroplasty is a versatile procedure in the treatment of inflammatory anterior urethral strictures. The dorsal pedicle flap may be anatomically and functionally more logical as compared to the traditional ventrally placed flap.

Laparoscopic surgeries for the bladder.

Various reparative, reconstructive, extirpative, and miscellaneous surgeries of the bladder with laparoscopic techniques are in the process of evolution. Our increasing expertise enhanced by improved instrumentation make these procedures feasible and encourage us to venture into this relatively less explored arena of laparoscopic urology.

Ureteroscopic lithotripsy using mini-endoscope and Swiss lithoclast: experience in 147 cases.

To evaluate the efficacy of a semirigid mini-endoscope and the Swiss Lithoclast compared with a conventional rigid endoscope and ultrasound, the results of transurethral ureteroscopic lithotripsy in 147 patients over a period of 30 months were analyzed according to the type of ureteroscope (rigid v semirigid) and energy (ultrasound v Lithoclast) used. In the initial 25 cases (Group I), a conventional rigid ureteroscope and ultrasound were used. The latter 122 patients (Group II) were subjected to ureteroscopic lithotripsy using a miniscope and the Lithoclast. The results were superior in Group II with respect to the overall success rate (p = 1.6 x 10[-2]), first-attempt success rate (p = 2.9 x 10[-4]), and the need for ureteral dilation (P = 1.0 x 10[-6]) compared with Group I. There were no major complications. Overall, minor complications (hematuria and urinary tract infection) were observed in 25% of the cases. Further, the results of ureteroscopic lithotripsy in Group II were comparable to those of SWL in situ for upper ureteral calculi and better than for those located in the iliac and lower ureter as reported previously. Our results demonstrate that the Swiss Lithoclast provides effective fragmentation of even hard and smooth stones without increasing the complication rate. This lithotripter is reliable, safe, and simple to operate. In addition, the cost of maintenance is almost nil.

In vitro anthelmintic activity of root-tuber extract of Flemingia vestita, an indigenous plant in Shillong, India.

The in vitro activity of root-tuber-peel extract of Flemingia vestita, an indigenous plant consumed by the natives in Northeast India, was tested against helminth parasites. Live parasites (nematode: Ascaris suum from pigs, A. lumbricoides from humans, Ascaridia galli and Heterakis gallinarum from domestic fowl; cestode: Raillietina echinobothrida from domestic fowl; trematode: Paramphistomum sp. from cattle) were collected in 0.9 % physiological buffered saline (PBS) and maintained at 37 +/- 1 degrees C. In vitro treatment of the parasites with the crude extract (50 mg/ml) in PBS revealed complete immobilization of the trematode and cestode in about 43 and 20 min, respectively. However, the cuticle-covered nematodes did not show any change in physical activity and remained viable even after a long period of exposure to the extract. Exposure of R. echinobothrida to genistein (0.5 mg/ml), an active principle isolated from the root-tuber peel, caused spontaneous loss of movement (paralysis) in 4.5 h, which was slower than the time required for praziquantel, the reference flukicide and cestodicide. The treated parasites showed structural alteration in their tegumental architecture. This study suggests the vermifugal activity of this plant extract against trematodes and cestodes.