Using local correlation in kernel-based smoothers for dependent data

We consider the general problem of smoothing correlated data to estimate the nonparametric mean function when a random, but bounded, number of measurements is available for each independent subject. We propose a simple extension to the local polynomial regression smoother that retains the asymptotic properties of the working independence estimator, while typically reducing both the conditional bias and variance for practical sample sizes, as demonstrated by exact calculations for some particular models. We illustrate our method by smoothing longitudinal functional decline data for 100 patients with Huntington's disease. The class of local polynomial kernel-based estimating equations previously considered in the literature is shown to use the global correlation structure in an apparently detrimental way, which explains why some previous attempts to incorporate correlation were found to be asymptotically inferior to the working independence estimator.     

Studies on production of ajmalicine in shake flasks by multiple shoot cultures of Catharanthus roseus

The effects of different concentrations of indole-3-acetic acid (IAA) and benzyladenine (BA) on production of ajmalicine by multiple shoot cultures of Catharanthus roseus (C. roseus) were studied. By supplementing Murashige and Skoog's (MS) medium with a high concentration of IAA (11.42 microM) and a low concentration of BA (2.22 microM), shoot cultures accumulated high levels of ajmalicine. When culture medium was fortified with a low concentration of IAA (2.85 microM) and a high concentration of BA (8.90 microM), shoots released high levels of ajmalicine into the culture medium. Quantification of ajmalicine was performed by high performance liquid chromatography (HPLC). The highest concentration of ajmalicine production (0.166% dry wt) was obtained by shoot cultures grown in MS medium containing IAA (11.42 microM) on 20 days of cultivation. Shoot cultures accumulated ajmalicine 4.2-fold more in IAA (11.42 microM) supplemented medium compared with the high concentration of BA (8.90 microM). The content of ajmalicine concentration in the medium was quantified. Shoot cultures grown in BA (8.90 microM) supplemented medium released the maximum production of ajmalicine (0.853 g/L) into the culture medium after 15 days of cultivation. The experimental data show that the secretion of ajmalicine was 2-fold more into the culture medium supplemented with a high concentration of BA compared to that with a low concentration of BA. Data presented here show that production of ajmalicine by shoot cultures is not correlated with growth rate. Dimeric indole alkaloids vincristine and vinblastine were not present in shoot cultures. Ajmalicine production by shoot cultures was 2.4-fold higher compared to leaves of 1-year-old naturally grown plants.     

Organogenesis and embryogenesis from diverse explants in pigeonpea (Cajanus cajan L.)

Seed and seedling expiants of pigeonpea were evaluated for organogenesis and somatic embryogenesis. De novo plant regeneration through organogenesis was obtained from mature cotyledons, primary leaves and roots of seedlings. Production of multiple shoots from the cotyledonary node was observed in cultures of whole seeds on 6-benzylaminopurine enriched medium. Somatic embryos were induced from immature cotyledons and embryonal axes, however, well-developed plants could not be derived from these embryos. The regenerants obtained through organogenesis were transferred to the field and grown to maturity.     

A review of the Pterogeniidae (Goleoptera)

The Pterogeniidae, a family of beetles from Indoaustralia, are revised. They comprise five genera and 24 species. Three genera and 17 species are described as new and one species is synonymized. It is shown that the male and particularly the female genitalia provide useful means for species definition. The phylogenetic relationships are discussed based on a cladistic analysis of 23 morphological characters using PAUP. The analysis resulted in a single cladogram with following grouping: ( Kryptogenius + ( Tychogenius + ( Katagenius + ( Plerogenins + Histanocerus )))). For rooting the cladogram and polarizing the characters, Sivacrypticus indicus (Archeocrypticidae) was used as an outgroup. The majority of the species is restricted to insular tropical Asia and Oceania but four of them extend their range onto the Malayan Peninsula. Another four species are known only from continental Asia, i.e. two species from South India and one each from Malayan Peninsula and Vietnam respectively. Species of Kryptogenius, Pterogenius, Katagenius and Tychogenius are highly endemic and could therefore potentially be useful for analysing areas of endemism. For this, however, the cladistic relationships should be resolved at species level. Species of Histanocerus are more widely distributed but none is found on both sides of Wallace's line.     

Purification and characterization of a hemoglobin degrading aspartic protease from the malarial parasite Plasmodium vivax

Aspartic proteases of human malarial parasites are thought to play key roles in essential pathways of merozoite release, invasion and host cell hemoglobin degradation during the intraerythrocytic stages of their life cycle. Therefore, we have purified and characterized Plasmodium vivax aspartic protease, to determine if this enzyme can be used as potential drug target/immunogen, and its inhibitors as potential antimalarial drug. The P. vivax aspartic protease has been purified by a combination of ion exchange and size exclusion chromatographies and HPLC. Its properties were examined in order to define a role in the hemoglobin degradation process. The purified enzyme migrated as a single band on native PAGE and SDS/PAGE with a molecular mass of 40 kDa. Gelatin zymogram analyses revealed a clear zone of proteolytic activity corresponding to the band obtained on native PAGE and SDS/PAGE. The enzyme has an optimal pH of 4.0 and exhibits its highest activity at 37 degrees C. The enzyme is inhibited by pepstatin, but not by other inhibitors including o-phenanthroline, EDTA, PMSF or E-64, supporting its designation as an aspartic protease; its IC50 value was found to be 3.0 microM. A Lineweaver Burk double reciprocal plot with pepstatin shows that the inhibition is competitive with respect to the substrate. Ca2+ and Mg2+ ions enhance the protease activity, whereas Cu2+ and Hg2+ ions were found to be inhibitory. The pivotal role of aspartic protease in initiating hemoglobin degradation in P. vivax malaria parasite is also demonstrated.     

Economic Impact of the Clinical Benefits of Bariatric Surgery in Diabetes Patients With BMI ≥35 kg/m2

The medical costs for a type 2 diabetes patient are two to four times greater than the costs for a patient without diabetes. Bariatric surgery is the most effective weight‐loss therapy and has marked therapeutic effects on diabetes. We estimate the economic effect of the clinical benefits of bariatric surgery for diabetes patients with BMI ≥35 kg/m². Using an administrative claims database of privately insured patients covering 8.5 million lives 1999–2007, we identify obese patients with diabetes, aged 18–65 years, who were treated with bariatric surgery identified using Healthcare Common Procedure Coding System codes. These patients were matched with nonsurgery control patients on demographic factors, comorbidities, and health‐care costs. The overall return on investment (RoI) associated with bariatric surgery was calculated using multivariate analysis. Surgery and control patients were compared postindex with respect to diagnostic claims for diabetes, diabetes medication claims, and adjusted diabetes medication and supply costs. Surgery costs were fully recovered after 26 months for laparoscopic surgery. At month 6, 28% of surgery patients had a diabetes diagnosis, compared to 74% of control patients (P < 0.001). Among preindex insulin users, insulin use dropped to 43% by month 3 for surgery patients, vs. 84% for controls (P < 0.001). By month 1, medication and supply costs were significantly lower for surgery patients (P < 0.001). The therapeutic benefits of bariatric surgery on diabetes translate into considerable economic benefits. These data suggest that surgical therapy is clinically more effective and ultimately less expensive than standard therapy for diabetes patients with BMI ≥35 kg/m².     

Pre-plant bacterisation: a strategy for delivery of beneficial endophytic bacteria and production of disease-free plantlets of black pepper (Pipernigrum L.)

Naturally occurring endophytic bacteria from black pepper vines were found to exhibit strong antagonistic activities against Phytophthora capsici and Radopholus similis. In order to deliver these bacterial strains, as well as to produce disease-free plantlets of black pepper, a pre-plant stem and root bacterisation was standardised. Stem bacterisation with endophytic Pseudomonas spp. was found to suppress P. capsici infection (over 90% reduction in lesion length) on cut shoots. Pre-plant root bacterisation with Pseudomonas aeruginosa, Pseudomonas putida and Bacillus megaterium yielded over 60% of plantlets free from P. capsici infection on roots. Curtobacterium luteum and B. megaterium recorded over 70% reduction of nematode population in soil with concomitant production of over 65% of nematode-free plantlets. Besides protecting the plants from the pathogens, the bacteria were also found to enhance the growth of rooted cuttings. The biocontrol potential of the above endophytic bacteria and their exploitation for disease management in the black pepper nursery are discussed.     

Luteinising hormone,follicle stimulating hormone and gonadotropin releasing hormone immunoreactivity in two insects: Locusta migratoria migratoroides R&F and Sarcophaga bullata (Parker)

Summary

Materials immunologically related to luteinising hormone (LH), follicle stimulating hormone (FSH) and the gonadotropin releasing hormone (GnRH) were localised in cerebral tissue of Locusta migratoria and Sarcophaga bullata by means of the peroxidase-antiperoxidase method. Several polyclonal and a monoclonal antisera were used. From the third larval instar a positive reaction was observed in cells located in several parts of the brain. Each antiserum reacted with a constant number of well defined cells and nerve fibers. No differences between sexes were observed.