Pyrido[1,2-a]pyrimidin-4-ones as antiplasmodial falcipain-2 inhibitors.

Plasmodium falciparum cysteine protease falcipain-2 (FP-2) is a promising target for antimalarial chemotherapy and inhibition of this protease affects the growth of parasite adversely. A series of pyrido[1,2-a]pyrimidin-4-ones were synthesized and evaluated for their in vitro FP-2 inhibitory potential. Compounds (14,17) showed excellent FP-2 inhibition and can serve as lead compounds for further development of potent FP-2 inhibitors as potential antimalarial drugs.

Development of high-voltage pulse-slicer unit with variable pulse duration for pulse radiolysis system.

A high-voltage pulse-slicer unit with variable pulse duration has been developed and integrated with a 7 MeV linear electron accelerator (LINAC) for pulse radiolysis investigation. The pulse-slicer unit provides switching voltage from 1 kV to 10 kV with rise time better than 5 ns. Two MOSFET based 10 kV switches were configured in differential mode to get variable duration pulses. The high-voltage pulse has been applied to the deflecting plates of the LINAC for slicing of electron beam of 2 µs duration. The duration of the electron beam has been varied from 30 ns to 2 µs with the optimized pulse amplitude of 7 kV to get corresponding radiation doses from 6 Gy to 167 Gy.

OCT-based arterial elastography: robust estimation exploiting tissue biomechanics.

We present a novel multi-resolution variational framework for vascular optical coherence elastography (OCE). This method exploits prior information about arterial wall biomechanics to produce robust estimates of tissue velocity and strain, reducing the sensitivity of conventional tracking methods to both noise- and strain-induced signal decorrelation. The velocity and strain estimation performance of this new estimator is demonstrated in simulated OCT image sequences and in benchtop OCT scanning of a vascular tissue sample.

Semisynthetic modifications of hemiaminal function at ornithine unit of mulundocandin, towards chemical stability and antifungal activity.

Mulundocandin (1), is an echinocandin class of lipopeptide. It has wide spectrum of antifungal activity against Candida and Aspergillus species. Semisynthetic modification at Ornithine-5-hydroxyl (hemiaminal function) of 1 was carried out to improve solution stability and hence in vivo activity. Synthesis of ether (C-OR), thioether (C-SR) and C-N linkage at hemiaminal function have been described. All synthetic analogues were evaluated for their stability in aqueous solution and found to be more stable than mulundocandin. Antifungal activity of Orn-5 analogues was evaluated both in vitro against Candida albicans and Aspergillus fumigatus by agar well method and in vivo (oral and intraperitoneal) in C. albicans infected Swiss mice. Results of in vivo assays of analogues 2-9 by the oral route suggests that the introduction of either oxygen nucleophiles (-OR) or sulphur nucleophiles (-SR), at either Orn-5 or at both Orn-5 and HTyr-4 positions, results in retaining the activity of the parent compound with improved aqueous stability in most cases. Compound 9 has shown improved antifungal activity in comparison to mulundocandin by oral application in Swiss mice.

Detection of MEF-1 laboratory reference strain of poliovirus type 2 in children with poliomyelitis in India in 2002 & 2003.

BACKGROUND & OBJECTIVES: Significant progress has been made towards eradication of poliomyelitis in India. Surveillance for acute flaccid paralysis (AFP) has reached high standards. Among the 3 types of polioviruses, type 2 had been eliminated in India and eradicated globally as of October 1999. However, we isolated wild poliovirus type 2 from a small number of polio cases in northern India in 2000 and again during December 2002 to February 2003. Using molecular tools the origin, of the wild type 2 poliovirus was investigated. METHODS: Polioviruses isolated from stool samples collected from patients with AFP were differentiated as wild virus or Sabin vaccine-like by ELISA and probe hybridization assays. Complete VP1 gene nucleotide sequences of the wild type 2 poliovirus isolates were determined by reverse transcriptase polymerase chain reaction (RT-PCR), followed by cycle sequencing. VP1 nucleotide sequences were compared with those of wild type 2 polioviruses that were indigenous in India in the past as well as prototype/laboratory strains and the GenBank database. RESULTS: Wild poliovirus type 2 was detected in stool samples from 6 patients with AFP in western Uttar Pradesh and 1 in Gujarat. In addition, the virus was isolated from one healthy contact child and from environmental sewage sample in Moradabad where three of these patients were reported. These isolates were identified as genetically closely related to laboratory reference strain MEF-1. Molecular characterization of the isolates confirmed that there was no evidence of extensive person-to-person transmission of the virus in the community. INTERPRETATION & CONCLUSION: Laboratory reference strain (MEF-1) of poliovirus type 2 caused paralytic poliomyelitis in 10 patients in September 2000 and November 2002 to February 2003. The origin of the virus was some laboratory as yet not identified. This episode highlights the urgent need for stringent containment of wild poliovirus containing materials in the laboratories across the country in order to prevent recurrence of such incidents.

Herniography: a prospective, randomized study between midline and left iliac fossa puncture techniques.

AIM: To determine whether an optimal site of injection exists for herniography. MATERIALS AND METHODS: This was a prospective, randomized study of 93 consecutive patients who were referred for herniography over a period of 9 months. Patients underwent either a left iliac fossa (LIF) or midline puncture. Parameters assessed included initial adequate needle placement, complications, pain scores and body mass index (BMI). The groups were compared using Chi-squared test for categorical data, Student's t-test for continuous data and the Mann-WhitneyU-test for skewed data, withP < 0.05 considered statistically significant RESULTS: Four complications were encountered (4%), and these were equally distributed between the two groups. Adequate initial positioning of the needle was similar in both groups. The volume of local anaesthetic used was correlated with discomfort using a pain scale: a volume of >6 ml resulted in significantly more pain. More frequent initial adequate needle placement was observed in thin patients (BMI < 45 kg/m(2)) with experienced operators. Conversely, increased body mass index resulted in more difficult needle placement. CONCLUSION: Herniography is a safe procedure with few complications. There was no significant difference comparing the midline and LIF approaches.Nadkarni, S.et al. (2001). Clinical Radiology56, 389-392.

In vitro simulation and quantification of temporal jitter artifacts in ECG-gated dynamic three-dimensional echocardiography.

The image quality of dynamic 3-D echocardiography is limited by temporal jitter artifacts that result from the asynchronous acquisition of video frames with the cardiac cycle. This paper analyzes the source and extent of these artifacts using in vitro studies. Dynamic 3-D images of a myocardial motion phantom were reconstructed and analyzed for eight cardiac motion patterns. The extent of temporal jitter artifacts was quantified, first, from the images by computing temporal jitter maps and, second, predicted from the motion waveforms. Temporal jitter appeared as a pattern of streak artifacts converging at the axis of rotation of the imaging plane, for the rotational scanning approach used in our study. The results of the experimental analysis techniques were compared with the waveform analysis using linear regression analysis. The least squares line showed good correlation between the data (r > 0.9) and its deviation from the line of identity was calculated to be <9%.

Preimplantation genetic diagnosis of chromosomal abnormalities by multicolour fluorescence in situ hybridisation.

Preimplantation genetic diagnosis (PGD) is an early diagnosis of genetic disorders, prior to the onset of pregnancy. PGD incorporates the latest techniques in assisted reproduction and molecular genetics. Embryos or oocytes are biopsied during culture in vitro and genetic analysis is carried out on the blastomeres or polar bodies. Embryos shown to be free of the genetic disease under investigation are transferred to the uterus. Multicolour fluorescence in situ hybridisation (FISH) is used to diagnose numerical and certain structural abnormalities of chromosomes in the embryo. The common probes used are for chromosomes 13, 18, 21, X and Y. FISH can also be used for PGD of translocations, when one of the parents is a carrier. PGD was carried out recently in 4 cases using multicolour FISH. In one of the embryos, trisomy 18 was detected. Tetraploidy was seen in another embryo. Only chromosomally normal embryos were transferred back to the uterus. Care has to be taken while interpreting FISH signals as the signal may be split, diffused, superimposed or in a different focus.

Three-dimensional echocardiography: assessment of inter- and intra-operator variability and accuracy in the measurement of left ventricular cavity volume and myocardial mass.

Accurate left ventricular (LV) volume and mass estimation is a strong predictor of cardiovascular morbidity and mortality. We propose that our technique of 3D echocardiography provides an accurate quantification of LV volume and mass by the reconstruction of 2D images into 3D volumes, thus avoiding the need for geometric assumptions. We compared the accuracy and variability in LV volume and mass measurement using 3D echocardiography with 2D echocardiography, using in vitro studies. Six operators measured the LV volume and mass of seven porcine hearts, using both 3D and 2D techniques. Regression analysis was used to test the accuracy of results and an ANOVA test was used to compute variability in measurement. LV volume measurement accuracy was 9.8% (3D) and 18.4% (2D); LV mass measurement accuracy was 5% (3D) and 9.2% (2D). Variability in LV volume quantification with 3D echocardiography was %SEMinter = 13.5%, %SEMintra = 11.4%, and for 2D echocardiography was %SEMinter = 21.5%, %SEMintra = 19.1%. We derived an equation to predict uncertainty in measurement of LV volume and mass using 3D echocardiography, the results of which agreed with our experimental results to within 13%. 3D echocardiography provided twice the accuracy for LV volume and mass measurement and half the variability for LV volume measurement as compared with 2D echocardiography.

Methylsulfomycin I, a new cyclic peptide antibiotic from a Streptomyces sp. HIL Y-9420704.

Methylsulfomycin I (1) is a new cyclic peptide antibiotic isolated from the fermentation broth of a Streptomyces sp. HIL Y-9420704. Its structure was elucidated by NMR and GC-MS. The in vitro activity (MIC) against a wide range of Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-, and teicoplanin-resistant strains, is described.

Mathemycin B, a new antifungal macrolactone from actinomycete species HIL Y-8620959.

A new macrocyclic lactone antibiotic mathemycin B (1) was isolated from the fermentation broth of an Actinomycete sp. culture Y-8620959. The structure of 1 was elucidated by high-resolution MS and interpretation of 2D NMR results. Mathemycin B is active against a variety of phytopathogenic organisms.

Modified Gallie technique versus transarticular screw fixation in C1-C2 fusion.

The effectiveness of a modified Gallie technique versus Magerl and Seeman transarticular screw fixation was compared in the management of 27 patients with symptomatic atlantoaxial instability. Twelve patients were treated using a modified Gallie technique and postoperative halo vest immobilization. Atlantoaxial arthrodesis occurred in seven (58%) patients, stable fibrous union occurred in one patient, and pseudarthrosis with recurrent instability developed in four (33%) patients. Average followup was 6.9 years. All 15 patients treated using Magerl and Seeman transarticular screw fixation and postoperative soft collar immobilization had atlantoaxial arthrodesis develop. Average duration of followup was 4 years. One patient sustained vertebral artery injury during preparation for screw placement. Magerl and Seeman transarticular screw fixation provides stability and more reliably produces atlantoaxial arthrodesis than the Gallie technique provides in patients with atlantoaxial instability without the need for rigid postoperative bracing. Potential for vertebral artery exists despite apparent accurate screw placement. To ensure that safe transarticular screw placement is possible, preoperative fine cut axial computed tomography with reconstructions is required to assess vertebral artery position and C2 isthmus anatomy. A proportion of patients have anatomy unsuitable for screw placement. Traditional wiring techniques are indicated in these patients.

Effect of passively transferred anti-poliovirus antibodies on seroconversion.

A prospective study enrolling 50 mother-infant pairs was undertaken to determine the effect of maternal antibodies on poliovirus antibody titres and seroconversion rates in infants and to determine the difference in titres and seroconversion rates following three and five doses of oral poliovaccine (OPV). Cord blood samples and samples collected 4 weeks after 3rd and 5th doses of trivalent oral poliovaccine were processed for estimation of anti-poliovirus antibody titres. These were expressed as geometric mean titres (GMT). Significance was analyzed using unpaired 't' test. The relationship between maternal antibody titres and seroconversion was determined by correlation coefficient test. Post OPV5 titres were significantly higher than post OPV3 titres for type 1 and type 2 polioviruses. Seroconversion rates against type 1, 2 and 3 polioviruses were 92.9%, 100.0% and 92.9% following OPV3 and 100.0%, 100.0% and 93.2% following OPV5. The cord blood titres did not have any relation to post-OPV3 or post-OPV5 titres. Although there is significant passive transfer of poliovirus antibodies across the placenta, this does not affect titres achieved after immunization. Post-OPV5 titres against type 1 and type 2 viruses are significantly higher than post-OPV3 titres. The seroconversion rates following OPV5 are higher than those obtained post-OPV3 but this difference is not statistically significant.

Comparison of the Ames, Randox and Roche methods with the Synermed method for the determination of serum iron concentrations on nondialysis and dialysis specimens.

OBJECTIVES: To evaluate the Ames, Randox, Roche, and Synermed methods for the measurement of serum iron and to investigate patterns of possibly discrepant results in dialysis patients. METHODS: Assays were performed on the Cobas Fara II analyzer. Precision and accuracy studies were conducted; recovery studies were done by adding pooled serum from dialysis patients to an assayed human serum-based control. Patient comparisons included over 150 nondialysis patients and 30 dialysis patients. RESULTS: For the Ames, Randox, Roche and Synermed methods, the between-run precision was less than 2.80% with the normal aqueous iron standard; 2.00, 2.70, 0.80, and 2.00% for the four methods with the high serum iron control, respectively, and less than 2.30% with the serum pool. Using a pooled serum from dialysis patients, between-run precision was higher with all four methods. With an abnormal assayed human serum-based control, accuracy was over 98% for the four methods. Recoveries were 121% for the Ames and Randox methods and 104-105% for the Roche and Synermed methods. Accuracy as assessed with Murex EQAS specimens ranged from 71 to 80%, 71 to 96%, 98 to 99.5%, and 42 to 50% for the four methods, respectively. For comparisons of the Ames, Randox, and Roche methods with the Synermed method, difference analyses revealed biases (SD) for nondialysis patients of 1.9 (2.7), 1.5 (3.3), and 1.8 (2.2) mumol/L, respectively; and for dialysis patients of 8.2 (13.3), 5.1 (5.4), and 1.4 (1.7) mumol/L. Standard linear regression analyses and correlation coefficients are also provided. CONCLUSIONS: The Roche method was slightly more precise than the other methods. Using an abnormal assayed serum-based control, all methods showed good accuracy. Recovery studies with pooled serum from dialysis patients showed interferences with the Ames and Randox methods and good recovery with the Roche and Synermed methods. With the bovine serum-based Murex samples, all but the Roche method yielded some low results; the Synermed method has been reported to suffer from matrix problems with bovine serum albumin. Based on recovery studies and difference analyses, the Ames and Randox methods revealed discrepancies in iron results for samples from dialysis patients. The Roche and Synermed methods appeared to be suitable for measurement of serum iron in dialysis patients.

Immunofluorometric assay of pepsinogen C and preliminary clinical applications.

We developed mouse monoclonal antibodies (Abs) against pepsinogen C with highly purified antigen isolated from gastric mucosa. The Abs were used to construct a two-site sandwich-type assay for pepsinogen C with time-resolved fluorometry as a detection technique. The assay has a detection limit of 0.1 microgram/L and is precise (within-run and day-to-day CVs < 11%). We used this assay to measure pepsinogen C in seminal plasma, breast cyst fluid, amniotic fluid, male and female serum, serum from patients with prostate cancer, urine, breast tumor cytosolic extracts, breast milk, and cerebrospinal fluid. Highest pepsinogen C concentrations were in seminal plasma, followed by breast cyst fluid and amniotic fluid. We found no correlation between prostate-specific antigen concentrations and concentrations of pepsinogen C in serum of prostate cancer patients, and concluded that this marker is not useful for either diagnosing or monitoring prostatic carcinoma. The availability of a highly sensitive, reliable, and convenient method for quantifying pepsinogen C will allow investigations into the possible diagnostic value of this analyte in various clinical conditions, including benign breast diseases, breast cancer, fertility, and pregnancy.