Experiment and FEM Analysis of Silica Nanoparticle-Based Impedance Immunosensor for Sensitivity Enhancement.

This article investigates the impact of incorporating silica nanoparticles of varying diameters in label free impedance immunosensor. It has been observed that even if the surface area improvement has been adjusted to be similar for all the diameters, the sensitivity is enhanced by five times at a particular diameter of 100 nm due to the optimum combination of intersection with electric field lines and surface convexity. This study has enabled the detection of 0.1 fM Hep-B surface antigen with a reliable sensitivity of around 75%. Further, it has been observed that the SNR corresponding to 0.1 fM is 20 dB only for 100 nm particle. This SNR is comparable to a recent report on Hep-B virus detection but the limit of detection in the proposed sensor is lowered by more than three orders of magnitude.

Pathogenicity of Candida viswanathii for normal and cortisone-treated mice.

The pathogenicity of Candida viswanathii, PCI 501/1 (CBS 4024), originally isolated from CSF of a fatal case of meningitis in India, is reported. Also, included is a global overview of the occurrence of C. viswanathii in clinical and environmental sources. The investigation was done in normal and cortisone-treated albino mice challenged intravenously with variable doses of 1×10(6), 4×10(6) and 16×10(6) actively growing yeast cells of the fungus. The animals were kept under observation up to 3 weeks when they were sacrificed for a mycological and histopathologic study. As apparent from the data on morbidity and mortality, the species exhibited low virulence for normal mice, whereas it caused significantly higher mortality (P<0.0008) and morbidity (macroscopic lesions) (P<0.0004) in cortisone group. Likewise, there was overall higher recovery of C. viswanathii in culture from the cortisone-treated than in the normal group of mice. These observations are indicative of C. viswanathii being an opportunistic pathogen. It is recognized that a definitive identification of C. viswanathii requires mycological expertise for comprehensive phenotypic characterization or the application of expensive techniques such as Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) and molecular techniques, facilities for which are generally lacking in a vast majority of laboratory diagnostic centers especially in developing countries. Consequently, the prevalence of C. viswanathii in clinical and environmental samples is currently likely to be underestimated.

Biodegradable citrate-based polyesters with S-nitrosothiol functional groups for nitric oxide release.

Nitric oxide (NO) is a biologically-active free radical involved in numerous physiological processes such as regulation of vasodilation, promotion of cell proliferation and angiogenesis, and modulation of the inflammatory and immune responses. Furthermore, NO has demonstrated the ability to mitigate the foreign body response that often results in the failure of implanted biomedical devices. Although NO has promising therapeutic value, the short physiological half-life of exogenous NO complicates its effective delivery. For this reason, the development of NO-releasing materials that permit the localized delivery of NO is an advantageous method of utilizing this molecule for biomedical applications. Herein, we report the synthesis and characterization of biodegradable NO-releasing polyesters prepared from citric acid, maleic acid, and 1,8-octanediol. NO release was achieved by incorporation of S-nitrosothiol donor groups through conjugation of cysteamine and ethyl cysteinate to the polyesters, followed by S-nitrosation with tert-butyl nitrite. The extent of NO loading and the release properties under physiological conditions (pH 7.4 PBS, 37 °C) were determined by chemiluminesence-based NO detection. The average total NO content of poly(citric-co-maleic acid-co-1,8-octanediol)-cysteamine was determined to be 0.45 ± 0.07 mol NO g-1 polymer, while the NO content for poly(citric-co-maleic acid-co-1,8-octanediol)-ethyl cysteinate was 0.16 ± 0.04 mol NO g-1 polymer. Continuous NO release under physiological conditions was observed for at least 6 days for the cysteamine analog and 4 days for the ethyl cysteinate analog. Cell viability assays and morphological studies with human dermal fibroblasts indicated an absence of toxic leachates at a cytotoxic level, and suggested that these citrate-based polyesters may be suitable for future biomedical applications.

Ultrasound spectrum in intraductal papillary neoplasms of breast.

Intraductal papillary neoplasms (IPNs) of breast form a wide spectrum of pathological changes with benign intraductal papilloma occupying one end of the spectrum and papillary carcinoma at the other end. Intraductal papillomas are known to occur anywhere within the ductal system and are broadly classified into central and peripheral types. Intraductal papillary carcinoma is an uncommon ductal malignancy forming papillary structures, and these lesions characteristically lack the myoepithelial layer present in benign papillary neoplasms. Three basic patterns of IPNs are recognized on ultrasound - intraductal mass with or without ductal dilatation, intracystic mass and a predominantly solid pattern with the intraductal mass totally filling the duct. Benign papillomas are known to exhibit calcifications which tend to be extremely dense and coarse. IPNs are highly vascular tumours and have a propensity to bleed spontaneously. A distinct vascular pedicle is identified within the central core of IPNs, with branching vessels arborising within the mass. In an older age group, presence of a large solid component and evidence of spontaneous intracystic bleed are more suggestive of papillary carcinomas than benign papillomas. We have serially studied 42 cases of intraductal papillary neoplasms with sonomammography and mammography from 2001 to 2004.

A spectrum of coexistent tuberculosis and carcinoma in the breast and axillary lymph nodes: report of five cases.

Tuberculosis (TB) and breast cancer are common diseases in developing countries. Their coexistence in the breast and axillary lymph nodes is, however, rare. It can lead to overstaging of the breast cancer. Treatment compliance may also be difficult when two major illnesses exist. Five cases of coexistent breast cancer and TB are presented with regard to presentation and outcome, with a review of the literature.

Small bowel metastases from esophageal and oropharyngeal cancers.

Intestinal metastases are uncommon. Lungs and skin are the common sites of primary tumor. We report two men (52- and 67-year-old) with small bowel metastases from esophageal and oropharyngeal carcinomas.

Effect of alcohol feeding mode on the biosynthesis of poly (3-hydroxybutyrate-co-3-hyroxyvalerate).

An alcohol utilizing Alcaligenes eutrophus produced poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) copolymer under phosphate limitation. Fermentation was performed for 42-46 h in a computer-controlled 5-L working volume fed-batch fermentor using ethanol and propanol as carbon sources. The culture experienced phosphate limitation in approximately 19 h. When propanol was used as a sole carbon source, 24 g/L of copolymer with 36.5 mol % of hydroxyvalerate (HV) was produced at a polymer yield of 0.41 g polymer/g alcohol (g/g) and an average polymer production rate of 0.08 g polymer/g residual biomass-h (g/g-h). Two experiments switching alcohol after phosphate exhaustion resulted in better polymer production (g/L), polymer yield (g/g) on alcohol, HV yield (g/g) on propanol, and average polymer production rate (g/g-h) as compared to propanol run without alcohol switching. One switching experiment was from a mixture of 50% ethanol and 50% propanol to 100% propanol and the other experiment was from 100% ethanol to a mixture of 65% ethanol and 35% propanol. Polymer yield for these two experiments was 0.51 g/g and 0.46 g/g, respectively. However, HV mol % in the copolymer for these two runs (30.8 mol % 12.6 mol % respectively) was lower compared to propanol run without alcohol switching (3605 mol %). Direct switch from ethanol to propanol did not support cell growth and polymer production. Polymer production rate and polymer yield changed with time, and the pattern was dependent upon the alcohol feeding mode.

Modeling and optimising lactose fermentation using a fluorosensor.

Lactose has been fermented in a Tokyo Rikakikai Fermentor using two percent seeding at various temperatures. The progress of the reaction was followed by measuring the fluorescent signal due to NADH with a Dr. Ingold (Switzerland) fluorosensor which has an excitation wave length of 360 nm and measurement wavelength of 450 nm. The optimum temperature for this fermentation reaction is 34 degree celsius. At this temperature while biomass growth rate and final biomass concentration are a maximum the time taken to reach the final biomass concentration and lag time are a minimum. The fluorescent voltage vs time data fitted a first order plus dead time model with an error of less than one percent. The present work is in good agreement with earlier work on glucose and lactose fermentation with one percent seeding. The increase in seeding from one to two percent has improved the optimum parameters studied. Further work on higher seeding concentration and higher order models is in progress.

Pathogenicity of some ordinarily harmless yeasts for cortisone-treated mice.

The pathogenicity for normal and cortisone-treated mice of Candida requinyii, Pichia etchellsii, Candida famata (Torulopsis candida) Trichosporon cutaneum and Sterigmatomyces aphidis, isolated from foodstuffs or clinical material, is reported. The test species proved nonpathogenic to normal mice inoculated intravenously with up to 10(7) cells. There was neither any mortality nor gross or microscopic lesions, and cultures were negative from the visceral organs and brain when these animals were necropsied after 3 weeks of observation. In cortisone-treated mice, on the other hand, the yeasts caused mortalities, the extent of which varied according to the infecting species and the challenge dose. Candida requinyii was the most pathogenic species, causing 100% mortality in 8 days, followed by S. aphidis, C. famata, T. cutaneum and P. etchellsii which killed 75%, 50%, 38% and 25% of the infected animals. Apart from the higher mortalities, C. requinyii and S. aphidis caused more frequent visceral lesions than did either T. cutaneum or C. famata. Involvement of the brain occurred more commonly with C. requinyii and T. cutaneum than with C. famata or S. aphidis. P. etchellsii was the only yeast that failed to incite any gross or microscopic lesions. The study re-emphasizes the pathogenic potential of ordinarily harmless fungi for immunosuppressed hosts.

Aspergillosis in imported penguins.

An outbreak of aspergillosis in imported penguins caused by Aspergillus fumigatus is described. The birds probably acquired the infection from the country of origin or during their transportation. Predisposing circumstances are discussed.

Conditional virulence of a p-aminobenzoic acid-requiring mutant of Aspergillus fumigatus.

The induced auxotrophy for p-aminobenzoic acid (PABA) resulted in a complete loss of virulence of Aspergillus fumigatus for normal as well as cortisone-treated mice. The PABA-requiring mutant of A. fumigatus survived in vivo for 4 to 7 days without causing any infection. However, it showed conditional virulence in animals receiving PABA in very small quantities. Repeated inoculations of the viable spores of the avirulent mutant strain gave favorable results in building immunity against intravenous challenge of the virulent strain. The immunogenicity of the PABA-requiring mutant was comparable with that of a wild strain of the fungus in agar gel double-diffusion tests using clinical and hyperimmune sera and in skin tests on patients with allergic bronchopulmonary aspergillosis.

Mycetoma of the knee due to Nocardia caviae.

Mycetoma of the knee, caused by Nocardia caviae and idangosed by culture and histopathology, occurred in a 20 year old farmer from a rural area of Varanasi District in Uttar Pradesh, India. The isolate was pathogenic to mice and it showed close agreement with the standard description of the species. It is suggested that infection due to this species has a higher prevalence than is currently recognized.