Utilization Practices of Inferior Vena Cava Filters at an Academic Medical Center

INTRODUCTION

 Anticoagulation is the mainstay of management for patients with venous thromboembolism (VTE), which includes deep vein thrombosis (DVT) and pulmonary embolism (PE). Inferior vena cava (IVC) filters are indicated in select patients who are not candidates for anticoagulation. There is a lack of quality evidence supporting other indications. In addition, long-term benefits and safety profiles of IVC filters have not been established. We investigated the utilization practice of IVC filters in a contemporary series of patients in a tertiary academic medical center.

METHODOLOGY

 A retrospective review of 200 patients who received IVC filters at Virginia Commonwealth University (VCU) Medical Center in the years 2017 and 2018 was conducted. Adult patients 18 years of age or older with or without cancer were included, and patients were selected consecutively until data on 200 patients were collected. Data on patient demographics, an indication of IVC filter placement, filter retrieval rate, and re-thrombosis events over a median follow-up period of nine months were extracted from the electronic medical record and analyzed.

RESULTS

A total of 200 patients (105 male and 95 female) were included with a median age of 61 years (range 17-92 years). Of the 200 patients, 97 (48.5%) had a DVT, 28 (14%) had a PE, 73 (36.5%) had both a PE and DVT, and 2 (1%) had thrombosis at other sites. A total of 130 (65%) patients had an IVC filter placed because of a contraindication to anticoagulation, while 70 (35%) had an IVC filter placed for other nonstandard indications, which included new or worsening VTE despite anticoagulation, recent VTE who must have anticoagulation held during surgery, primary prevention in high-risk patients, and extensive disease burden among other reasons. Seventy-two (36%) patients had active malignancy at the time of filter placement, and 64 (32%) were lost to follow-up. Of the 119 patients who were potentially eligible for filter retrieval, 55 (46%) patients had their IVC filters removed at a median of five months after insertion. Of the 55 patients who had IVC filters removed, 8 (14.5%) patients experienced a re-thrombosis event within a median follow-up of 39 months. Of the 145 patients who still had their filter in place at the time of death or last follow-up, 5 (3.4%) patients experienced a re-thrombosis event within a median follow-up of three months.

CONCLUSIONS

 One-third of the patients in this series had an IVC filter placed without a standard indication, and less than half of them had the IVC filters removed within one year of placement. Additionally, one-third of the patients were lost to follow-up, highlighting the need for improved structured follow-up programs and education among both patients and providers regarding the indications for placement and retrieval to minimize complications.

MDA-9/Syntenin in the tumor and microenvironment defines prostate cancer bone metastasis

Bone metastasis is a frequent and incurable consequence of advanced prostate cancer (PC). An interplay between disseminated tumor cells and heterogeneous bone resident cells in the metastatic niche initiates this process. Melanoma differentiation associated gene-9 (mda-9/Syntenin/syndecan binding protein) is a prometastatic gene expressed in multiple organs, including bone marrow-derived mesenchymal stromal cells (BM-MSCs), under both physiological and pathological conditions. We demonstrate that PDGF-AA secreted by tumor cells induces CXCL5 expression in BM-MSCs by suppressing MDA-9-dependent YAP/MST signaling. CXCL5-derived tumor cell proliferation and immune suppression are consequences of the MDA-9/CXCL5 signaling axis, promoting PC disease progression. mda-9 knockout tumor cells express less PDGF-AA and do not develop bone metastases. Our data document a previously undefined role of MDA-9/Syntenin in the tumor and microenvironment in regulating PC bone metastasis. This study provides a framework for translational strategies to ameliorate health complications and morbidity associated with advanced PC.

Can Costus afer be used for co-treatment of COVID-19, its symptoms and comorbidities? A novel approach for combating the pandemic and implications for sub-Saharan Africa

Despite the huge loss of lives and massive disruption of the world economy by the COVID -19 pandemic caused by SARS -CoV-2, scientists are yet to come out with an effective therapeutic against this viral disease . Several vaccines have obtained 'emergency approval ', but difficulties are being faced in the even distribution of vaccines amongst high- and low- income countries . On top of it, comorbidities associated with COVID -19 like diabetes, hypertension and malaria can seriously impede the treatment of the main disease, thus increasing the fatality rate . This is more so in the context of sub -Saharan African and south Asian countries . Our objective was to demonstrate that a single plant containing different phytoconstituents may be used for treatment of COVID -19 and comorbidities . Towards initial selection of a plant, existing scientific literature was scanned for reported relevant traditional uses, phytochemicals and pharmacological activities of a number of plants and their phytoconstituents pertaining to treatment of COVID-19 symptoms and comorbidities. Molecular docking studies were then performed with phytochemicals of the selected plant and SARS-CoV-2 components - Mpro, and spike protein receptor binding domain and hACE2 interface using AutoDock V ina. We showed that crude extracts of an indigenous African plant, Costus afer having traditional antidiabetic and antimalarial uses, has phytochemicals with high binding affinities for Mpro, and /or spike protein receptor binding domain and hACE2 interface; the various phytochemicals with predicted high binding energies include aferoside C, dibutyl phthalate, nerolidol, suginal, and ± -terpinene, making them potential therapeutics for COVID -19. The results suggest that crude extracts and phytochemicals of C. afer can function as a treatment modality for COVID -19 and comorbidities like especially diabetes and malaria .

Potential role of flavonoids against SARS-CoV-2 induced diarrhea

COVID-19, caused by the SARS-CoV-2 virus, can lead to massive inflammation in the gastrointestinal tract causing severe clinical symptoms. SARS-CoV-2 infects lungs after binding its spike proteins with alveolar angiotensin-converting enzyme 2 (ACE2), and it also triggers inflammation in the gastrointestinal tract. SARS-CoV-2 invades the gastrointestinal tract by interacting with Toll-like receptor-4 (TLR4) that induces the expression of ACE2. The influx of ACE2 facilitates cellular binding of more SARS-CoV-2 and causes massive gastrointestinal inflammation leading to diarrhea. Diarrhea prior to COVID-19 infection or COVID-19-induced diarrhea reportedly ends up in a poor prognosis for the patient. Flavonoids are part of traditional remedies for gastrointestinal disorders. Preclinical studies show that flavonoids can prevent infectious diarrhea. Recent studies show flavonoids can inhibit the multiplication of SARS-CoV-2. In combination with vitamin D, flavonoids possibly activate nuclear factor erythroid-derived-2-related factor 2 that downregulates ACE2 expression in cells. We suggest that flavonoids have the potential to prevent SARS-CoV-2 induced diarrhea.

Seasonal analysis of food items and feeding habits of endangered riverine catfish Rita rita (Hamilton, 1822)

This investigation presents the food and feeding activity of and endangered riverine catfish Rita rita, during February 2017-January 2018. A total of 225 fish individuals was analyzed for stomach contents by characterizing the dominant food items and morphometric features. The results divulged ten major food items consumed, preferably fish scales and eggs, teleost fishes, copepods, cladocerans, rotifers, and mollusks. Total length and body weight of fish varied between 9-34 cm (20.53 ± 6.90 cm) and 10-400 g (9125.94 ± 102.07 g), respectively. The index of relative importance (IRI%) showed the importance of rotifers over the other food items. Morisita's index of diet overlap indicated seasonal variations in catfish diets with summer and monsoon displaying the least overlap, while maximum overlap during monsoon and winter seasons. The non-metric multidimensional scaling (nMDS) indicated the close association between the food items available during summer and winter seasons with a significant difference among the seasons (ANOSIM, R = 0.638, P = 0.013). Levin's niche breadth index arranged in the order of 0.88>0.81>0.78>0.63>0.43 for the size classes of V, IV, III, II and I, respectively. The PCA explained 95.39% of the total variance among the food items and fish size groups. Small-sized fish individuals displayed a greater correlation with food items suitable for their mouth size. In conclusion, the variety and frequency of food items recorded indicated considerable feeding plasticity and opportunistic feeding behavior with a shift from carnivorous to omnivorous feeding nature. This study could render useful information on the food and feeding habits of R. rita and provide background for preparing its diet for future aquaculture practices.

Development of Biocompatible Iron-Carboxylate Metal Organic Frameworks for pH-Responsive Drug Delivery Application

Metal organic frameworks (MOFs), MIL-101-Fe (Materials of Institute Lavoisier), have been synthesized by solvothermal method. The as-synthesized MIL-101-Fe particles are observed to have hexagonal shaped morphology with average particle size ranging from 480 to 500 nm. The functionalization of the surface of as-synthesized MIL-101-Fe particles was done with the integration of amine group into the framework to facilitate the conjugation of the drug and other entities. Further, the drug conjugated MOF particles were coated with polyethyleneglycol (PEG) layer so as to extend the drug release time by controlling the faster pH mediated MOF degradation in biological buffers. pH dependent drug release study of the MOF particles was carried out at 3 different pH values, i.e., 5, 6 and 7.4. The drug release profiles showed that the drug released from NH₂-MIL-101-Fe takes less time which was further increased after coating the NH₂-MIL-101-Fe with polyethyleneglycol (PEG@Drug@NH₂-MIL-101-Fe). This confirmed that PEG coated particles have great stability for drug delivery application.

Evaluation of chromate reductase activity in the cell-free culture filtrate of Arthrobacter sp. SUK 1201 isolated from chromite mine overburden

Arthrobacter sp. SUK 1201, a chromate resistant and reducing bacterium isolated from chromite mine overburden of Sukinda valley, Odisha, India has been evaluated for its hexavalent chromium [Cr(VI)] reduction potential using cell-free culture filtrate as extracellular chromate reductase enzyme. Production of the enzyme was enhanced in presence of Cr(VI) and its reducing efficiency was increased with increasing concentration of Cr(VI). The Michaelis-Menten constant (Km) and the maximum specific velocity (Vmax) of the extracellular Cr(VI) reductase were calculated to be 54.03 μM Cr(VI) and 5.803 U mg(-1) of protein respectively showing high affinity towards Cr(VI). The reducing activity of the enzyme was maximum at pH 6.5-7.5 and at a temperature of 35 °C and was dependent on NADH. The enzyme was tolerant to different metals such as Mn(II), Mg(II) and Fe(III) and was able to reduce Cr(VI) present in chromite mine seepage. These findings suggest that the extracellular chromate reductase of Arthrobacter sp. SUK 1201 has a great promise for use in Cr(VI) detoxification under different environmental conditions, particularly in the mining waste water treatment systems.

Efficient photocatalytic degradation of rhodamine 6G with a quantum dot-metal organic framework nanocomposite

The hybrid structures of metal organic frameworks (MOFs) and nanoparticles may offer the realization of effective photocatalytic materials due to combined benefits of the porous and molecular sieving properties of MOF matrix and the functional characteristics of encapsulated nanoparticles. In this study, cadmium telluride (CdTe) quantum dots (QD) are conjugated with a europium-MOF for the synthesis of a novel nanocomposite material with photocatalytic properties. Successful synthesis of a QD/Eu-MOF nanocomposite was characterized with various spectroscopic and microscopic techniques. This QD/Eu-MOF is found to be an effective catalyst to complete the degradation of Rhodamine 6G dye within 50 min.

Muon-spin relaxation study of the double perovskite insulators Sr2 BOsO6 (B = Fe, Y, ln)

We present the results of zero-field muon-spin relaxation measurements made on the double perovskite insulators Sr2 BOsO6 (B = Fe,Y, In). Spontaneous muon-spin precession indicative of quasistatic long range magnetic ordering is observed in Sr2FeOsO6 within the AF1 antiferromagnetic phase for temperatures below [Formula: see text] K. Upon cooling below T2≈67 K the oscillations cease to be resolvable owing to the coexistence of the AF1 and AF2 phases, which leads to a broader range of internal magnetic fields. Using density functional calculations we identify a candidate muon stopping site within the unit cell, which dipole field simulations show to be consistent with the proposed magnetic structure. The possibility of incommensurate magnetic ordering is discussed for temperatures below TN = 53 K and 25 K for Sr2YOsO6 and Sr2InOsO6, respectively.

Partial characterization of an extracellular polysaccharide produced by the moderately halophilic bacterium Halomonas xianhensis SUR308

A moderately halophilic bacterium, Halomonas xianhensis SUR308 (Genbank Accession No. KJ933394) was isolated from a multi-pond solar saltern at Surala, Ganjam district, Odisha, India. The isolate produced a significant amount (7.87 g l(-1)) of extracellular polysaccharides (EPS) when grown in malt extract-yeast extract medium supplemented with 2.5% NaCl, 0.5% casein hydrolysate and 3% glucose. The EPS was isolated and purified following the conventional method of precipitation and dialysis. Chromatographic analysis (paper, GC and GC-MS) of the hydrolyzed EPS confirmed its heteropolymeric nature and showed that it is composed mainly of glucose (45.74 mol%), galactose (33.67 mol %) and mannose (17.83 mol%). Fourier-transform infrared spectroscopy indicated the presence of methylene and carboxyl groups as characteristic functional groups. In addition, its proton nuclear magnetic resonance spectrum revealed functional groups specific for extracellular polysaccharides. X-ray diffraction analysis revealed the amorphous nature (CIxrd, 0.56) of the EPS. It was thermostable up to 250 °C and displayed pseudoplastic rheology and remarkable stability against pH and salts. These unique properties of the EPS produced by H. xianhensis indicate its potential to act as an agent for detoxification, emulsification and diverse biological activities.

Phosphinic acid functionalized carbon nanotubes for sensitive and selective sensing of chromium(VI)

Single-walled carbon nanotubes (SWCNTs) have been functionalized with a phosphinic acid derivative 'bis(2,4,4-trimethylpentyl) phosphinic acid' (PA/d). It has been achieved by treating the chlorinated SWCNTs with PA/d at 80°C. Successful functionalization and different nanomaterial properties have been investigated by UV-vis-NIR, FTIR, Raman spectroscopy, AFM and FE-SEM. PA/d conjugated SWCNTs (CNT-PA) are dispersible in some common organic solvents, e.g. CH2Cl2, DMF, CHCl3, and THF. The 'CNT-PA' complex was spin-casted on boron doped silicon wafer. Thus fabricated sensing electrode is demonstrated for sensitive and selective electrochemical sensing of chromium(VI) ions. A linear response is obtained over a wide range of Cr(VI) concentration (0.01-10 ppb). The sensor's sensitivity and the limit of detection are observed to be 35 ± 4 nA/ppb and 0.01 ppb, respectively. The practical utility of the proposed sensor is demonstrated by determining the Cr(VI) concentration in an industrial effluent sample and an underground water sample.

Nanocomposite of europium organic framework and quantum dots for highly sensitive chemosensing of trinitrotoluene

Luminescent metal-organic frameworks (MOFs) are considered as next-generation sensor materials for small molecules and explosives. In the present work, a nanocomposite of luminescent europium organic framework (EuOF) and CdSe quantum dots (QDs) has been first time investigated for photoluminescence (PL) based highly sensitive detection of trinitrotoluene (TNT). The nanocomposite EuOF/QD has been synthesized by initiating the growth of EuOF in the presence of QDs. The successful synthesis of the product has been verified with the help of electron microscopy, X-ray diffraction analysis, and surface area measurements. Compared to EuOF alone, the EuOF/QD nanocomposite offers reproducible and stable measurements. The linear range of PL quenching based detection of TNT with EuOF/QD nanocomposite is 5-1000 ppb with the detection limit of 3 ppb. The detection of TNT with EuOF/QD is selective with respect to some other investigated aromatic compounds, such as phenol, o-cresol, toluene, benzene, nitrobenzene and nitrophenol.

Hexavalent chromium reduction by aerobic heterotrophic bacteria indigenous to chromite mine overburden

Microbiological analysis of overburden samples collected from chromite mining areas of Orissa, India revealed that they are rich in microbial density as well as diversity and dominated by Gram-negative (58%) bacteria. The phenotypically distinguishable bacterial isolates (130) showed wide degree of tolerance to chromium (2–8 mM) when tested in peptone yeast extract glucose agar medium. Isolates (92) tolerating 2 mM chromium exhibited different degrees of Cr⁺⁶ reducing activity in chemically defined Vogel Bonner (VB) broth and complex KSC medium. Three potent isolates, two belonging to Arthrobacter spp. and one to Pseudomonas sp. were able to reduce more than 50 and 80% of 2 mM chromium in defined and complex media respectively. Along with Cr⁺⁶ (MIC 8.6–17.8 mM), the isolates showed tolerance to Ni⁺², Fe⁺³, Cu⁺² and Co⁺² but were extremely sensitive to Hg⁺² followed by Cd⁺², Mn⁺² and Zn⁺². In addition, they were resistant to antibiotics like penicillin, methicillin, ampicillin, neomycin and polymyxin B. During growth under shake-flask conditions, Arthrobacter SUK 1201 and SUK 1205 showed 100% reduction of 2 mM Cr⁺⁶ in KSC medium with simultaneous formation of insoluble precipitates of chromium salts. Both the isolates were also equally capable of completely reducing the Cr⁺⁶ present in mine seepage when grown in mine seepage supplemented with VB concentrate.

Isolation and characterization of heavy metal resistant bacteria from Barak River contaminated with pulp paper mill effluent, South Assam

A group of 15 heavy metal resistant bacteria were isolated from Barak River contaminated with paper and pulp effluents. These isolates displayed different degrees of chromium tolerance. Four isolates showed 34 %-49 % of growth at a concentration of 4.0 mM of Cr(6+) and subjected to chromium reduction assay under aerobic condition. The isolate E (4) showed highest reduction (34.38 %) followed by E (3) and K(6)PA6, both showed 28.75 % reduction and then D (2) (27.5 %) after 72 h of incubation. These 4 isolates also showed different degrees of resistance to other heavy metals like Ni, Cu, Co and Cd. Antibiotic sensitivity profile of these selected bacterial strains was determined against 10 different antibiotics. Isolate E (4) appeared to be most susceptible being inhibited by eight antibiotics and resistant to penicillin G and ampicillin. The isolate E (3) was resistant to as many as five antibiotics and showed susceptible responses to the rest of the antibiotics. Both the isolates K(6)PA6 and D (2) were resistant to four antibiotics and showed intermediate to susceptible responses to the rest of the antibiotics.

Optimization of cultural conditions for growth associated chromate reduction by Arthrobacter sp. SUK 1201 isolated from chromite mine overburden

Arthrobacter sp. SUK 1201, a chromium resistant and reducing bacterium having 99% sequence homology of 16S rDNA with Arthrobacter sp. GZK-1 was isolated from chromite mine overburden dumps of Orissa, India. The objective of the present study was to optimize the cultural conditions for chromate reduction by Arthrobacter sp. SUK 1201. The strain showed 67% reduction of 2mM chromate in 7 days and was associated with the formation of green insoluble precipitate, which showed characteristic peak of chromium in to energy dispersive X-ray analysis. However, Fourier transform infrared spectra have failed to detect any complexation of end products of Cr(VI) reduction with the cell mass. Reduction of chromate increased with increased cell density and was maximum at 10(10)cells/ml, but the reduction potential decreased with increase in Cr(VI) concentration. Chromate reducing efficiency was promoted when glycerol and glucose was used as electron donors. Optimum pH and temperature of Cr(VI) reduction was 7.0 and 35 °C respectively. The reduction process was inhibited by several metal ions and metabolic inhibitors but not by Cu(II) and DNP. These findings suggest that Arthrobacter sp. SUK 1201 has great promise for use in Cr(VI) detoxification under a wide range of environmental conditions.

Androgen versus erythropoietin for the treatment of anaemia of pre-dialysis chronic kidney disease

Chronic kidney disease is a microvascular complication of diabetes mellitus (DM). Anemia is an important clinical manifestation to treat chronic kidney disease. Many subjects with poor socio-economic status having chronic kidney disease (CKD) and anaemia in a developing country can not afford the treatment with erythropoietin. This study has designed to see the efficacy of Nandrolone, a cheaper alternative; in comparison with recombinant human erythropoietin for management of anemia of pre-dialysis diabetic chronic kidney disease. Sixty adult diabetic patients with anaemia of chronic kidney disease on conservative treatment [Not on Hemodialysis (HD)] were enrolled. Patients were divided into two groups (Group 1 and Group 2) of 30 patients each. Group 1 patients received nandrolone deaconate 50 mg deep intramuscular and Group 2 recombinant human erythropoietin 100 IU per kilogram of body weight subcutaneously once weekly. Patients of both group received oral supplements in order to maintain body iron stores. All the relevant haematological and renal parameters were evaluated at the end of 3rd & 6th months. There was a statistically significant rise in haemoglobin concentration, packed cell volume, in both groups. The rise in haemoglobin concentration, in Group 2 was more marked followed by Group 1, at the end of 3rd, and 6th months. Nandrolone, though not equally effective, may be considered as a valid alternative therapy for the treatment of anemia of pre-dialysis diabetic chronic kidney disease to that of erythropoietin.

Production of poly-3-hydroxyalkanoic acids by a moderately halophilic bacterium, Halomonas marina HMA 103 isolated from solar saltern of Orissa, India

Halomonas marina HMA 103 (MTCC 8968), the moderately halophilic bacterium isolated and characterized from the solar saltern of Orissa, India, grows optimally at 10% (w/v) NaCl in culture medium and is able to synthesize poly(3-hydroxybutyrate) [P(3HB)] during growth. This study is an attempt to optimize the cultural conditions for efficient production of P(3HB) by H. marina in batch cultivation. Growth of the organism under shake-flask culture using 2% (w/v) glucose resulted in P(3HB) accumulation accounting for more than 59% of cell dry weight after 50 h of incubation. The optimum P(3HB) production was attained with a combined supply of NH4Cl and yeast extract as N-source, 0.01% (w/v) phosphate, 1.5% (w/v) sulphate and 10% (w/v) NaCl. Qualitative and quantitative 1HNMR and FT-IR analysis of cells grown in alkanoic acids (C3-C6) as sole source of carbon and co-substrates revealed synthesis of PHA co-polymers composed of 3-hydroxybutyric acid and 3-hydroxyvaleric acid [P(3HB-co-3HV)]. In two-step cultivation, accumulation of the co-polymer was significantly improved (80% CDW) in glucose medium supplemented with valerate (0.1%, w/v) as co-substrate and the polymer contained 88.1 and 12.8 mol% 3HB and 3HV monomers, respectively.

Natural bioactive compounds and biotechnological potential of marine bacteria

Adaptation of marine bacteria to the harsh environments has led to a rich biological and genetic diversity. Marine bacteria are attracting attention as new biotechnological resources. These bacteria can be a potential source of new bioactive compounds for industrial, agricultural, environmental, pharmaceutical and medical uses. The present paper reveals the potential of the marine bacteria with biotechnological applications related to antimicrobial drug discovery, environmental remediation, and developing new resources for industrial processes.

Studies on intracellular degradation of polyhydroxyalkanoic acid–polyethylene glycol copolymer accumulated by Azotobacter chroococcum MAL-201

Azotobacter chroococcum MAL-201 accumulates poly(3-hydroxybutyric acid) [PHB] when grown in glucose containing nitrogen-free Stockdale medium. The same medium supplemented with valerate alone and valerate plus polyethylene glycol (PEG) leads to the accumulation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [PHBV] and PEG containing PHBV-PEG polymers, respectively. The intracellular degradation of these polymers as studied in carbon-free Stockdale medium showed a rapid degradation of PHB followed by PHBV, while it was least in case of PHBV-PEG. The rate of such degradation was 44.16, 26.4 and 17.0 mg h(-1)l(-1) for PHB, PHBV and PHBV-PEG, respectively. During the course of such of PHBV and PHBV-PEG degradation the 3HB mol% of polymers decreased significantly with increase of 3HV mol fraction, the EG mol% in PHBV-PEG, however, remained constant. After 50h of degradation the decrease in intrinsic viscosity and molecular mass of PHBV-PEG were 37.5 and 43.6%, respectively. These values appeared low compared to PHB and PHBV. Moreover, the increasing EG content of polymer retarded their extent of degradation. Presence of PEG, particularly of low molecular weight PEG was inhibitory to intracellular PHA depolymerise (i-PHA depolymerase) activity and the relative substrate specificity of the i-PHA depolymerase of MAL-201 appeared to be PHB > PHBV > PHBV-PEG.

Thyroid disorders in Khulna district: a community based study

This study reports the prevalence of thyroid diseases and their relationship to autoimmunity in a population of Khulna district where goitre is not endemic. A survey was performed among citizens of a union of Khulna district. The study population consisted of a random sample of the students of primary schools, secondary schools and people of nearby areas. History taking, neck examination for goitre and blood examination for thyroid hormones was done from each subject. Blood sample was measured for thyroid hormones and thyroid microsomal antibody (TMAb) using radioimmunoassay method. Of the total 925 individual studied, 527 was female and 398 was male with age ranges from 2-62 years (mean 19.86 +/- 13.62 years). The overall occurrence of thyroid disease was estimated to be 20.43%. The spectrum of thyroid disorders showed highest incidence of diffuse goitre (7.35%), followed by sub-clinical hypothyroidism (6.59%), hypothyroidism (4.97%), hyperthyroidism (0.86%) and sub-clinical hyperthyroidism (0.65%). The incidence of thyroid disorders was observed to be highest in the 11-45 years age group (79.89%). Female outnumbered male, the ratio being 2.5:1 with preponderance of female subjects in all disease groups. The prevalence of all goitre was 10.49%. TMAb estimation was performed in 318 samples, of them 48 cases (15.09%) was found to be autoimmune thyroid disease. Of the total sub-clinical and overt hypothyroidism, the incidence of autoimmune thyroid disease was 29.29% and non-goitrous thyroid dysfunction was more common than goitrous one. Three of 38 (7.89%) euthyroid goitrous subjects showed positive antibody. Interestingly, 16 of 181 (8.84%) individual had a positive antibody, which was considered normal by neck examination. Goitre prevalence of 10.49% in this study indicates the region to be a mild iodine deficient area. Chronic autoimmune disease is likely to be one of the etiological factors for thyroid disorders in this southern zone.

Biosorption of cobalt by fungi from serpentine soil of Andaman

Fungi belonging to Aspergillus, Mortierella, Paecilomyces, Penicillium, Pythium, Rhizopus and Trichoderma, isolated from serpentine soil of Andaman (India) were screened for cobalt-resistance. Eleven out of total 38 isolated fungi which tolerated > 6.0 mM Co(II) were evaluated for cobalt biosorption using dried mycelial biomass. Maximum Co(II)-loading (1036.5 microM/g, 60 min) was achieved with Mortierella SPS 403 biomass, which removed almost 50% of 4.0 mM cobalt from the aqueous solution. Co(II)-sorption kinetics of Mortierella SPS 403 biomass was fast and appreciable quantities of metal [562.5 microM/g] was adsorbed during first 10 min of incubation. The metal biosorption capacity of the isolate was accelerated with increasing cobalt concentration, while it was reverse with increase of initial biomass. The optimum pH and temperature for Co(II) removal were 7.0 and 30 degrees C, respectively. However, Co(II)-uptake was inhibited in presence of other metals (Pb, Cd, Cu, Ni, Cr and Zn). Freundlich adsorption isotherm appropriately describes Mortierella SPS 403 biomass as an efficient Co(II)-biosorbent.

Incorporation of polyethylene glycol in polyhydroxyalkanoic acids accumulated by Azotobacter chroococcum MAL-201

Azotobacter chroococcum MAL-201 (MTCC 3853), a free-living nitrogen-fixing bacterium accumulates poly(3-hydroxybutyric acid) [PHB, 69% of cell dry weight (CDW)] when grown on glucose and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [PHBV with 19.2 mol% 3HV] when grown on glucose and valerate. Use of ethylene glycol (EG) and/or polyethylene glycols (PEGs) of low molecular weight as sole carbon source were detrimental to A. chroococcum growth and polymer yields. PEG-200, however, in the presence of glucose was incorporated into the polyhydroxyalkanoate (PHA) polymer. Addition of PEG-200 (150 mM) to culture medium during mid-log phase growth favored increased incorporation of EG units (12.48 mol%) into the PHB polymer. In two-step culture experiments, where valerate and PEG simultaneously were used in fresh medium, EG was incorporated most effectively in the absence of glucose, leading to the formation of a copolymer containing 18.05 mol% 3HV and 14.78 mol% EG. The physico-mechanical properties of PEG-containing copolymer (PHBV-PEG) were compared with those of the PHB homopolymer and the PHBV copolymer. The PHBV-PEG copolymer appeared to have less crystallinity and greater flexibility than the short-chain-length (SCL) PHA polymers.

Reduction of hexavalent chromium by cell-free extract of Bacillus sphaericus AND 303 isolated from serpentine soil

Cell-free extracts (CFEs) of chromium-resistant bacterium Bacillus sphaericus AND 303 isolated from serpentine soil of Andaman, India reduced Cr(VI) in in vitro condition, and the reductase activity was solely localized in the soluble cell-fractions (S12, S32, and S150). The enzyme was constitutive as the CFEs from cells grown in Cr(VI)-free and Cr(VI)-containing media reduced a more or less equal amount of Cr(VI). Optimum Cr(VI) reductase activity was obtained at an enzyme (S150) concentration equivalent to 4.56 mg protein/mL, 300 microM: Cr(VI) and pH 6.0 after 30 min incubation at 30 degrees C. The enzyme was heat labile; 80% of its activity was lost when exposed at 70 degrees C for 15 min. Kinetics of Cr(VI) reductase activity fit well with the linearized Lineweaver-Burk plot and showed a V(max) of 1.432 micromol Cr(VI)/mg protein/min and K(m) of 158.12 microM: Cr(VI). The presence of additional electron donors accelerated Cr(VI) reductase activity of CFE, and an increase of 28% activity over control was recorded with 1.0 microM: NADH. Heavy metal ions such as Ni(II), Cu(II), and Cd(II) were strong inhibitors of Cr(VI) reductase unlike that of 100 microM: Co(II), which retained 93% activity over control.

Occurrence of heavy metal-resistance in microflora from serpentine soil of Andaman

Serpentine soils collected from Saddle Hills, Chidyatapu and Rutland of Andaman Islands, India were analyzed for physico-chemical and microbiological characteristics and compared with those from adjacent non-serpentine localities. The serpentine soils contained high levels of nickel (1740.0-8033.4 mg/kg dry soil), cobalt (93.2-533.4 mg/kg dry soil) and chromium (302.9-4437.0 mg/kg dry soil), in addition to 62-152 g of iron and 37-60 g of magnesium per kg dry soil. Characteristically the serpentine soils showed low microbial density (6.2-11.3 x 10(6) colony forming unit/g soil) and activity (1.7-3.5 microg fluorescein/g dry soil/h) than non-serpentine outcrops. Serpentine microbial population was dominated by bacteria which represented 5.12 to 9.5 x 10(6) cfu/g of soil, while the fungal population ranged from 0.17 to 3.21 x 10(6) cfu/g of soil. A total of 342 (200 from serpentine and 142 from non-serpentine soils) isolates were compared for Ni, Co and Cr resistance. Serpentine microflora was in general, highly resistant than non-serpentine ones and showed a metal-resistance profile of Cr > Ni > Co. Amongst the serpentine isolates, 8 and 11 bacteria tolerated > 12.0 mM Ni and > 16.0 mM Cr respectively, while 6 fungal isolates showed a minimum inhibitory concentration (MIC) value > 8.0 mM Co. These 25 serpentine strains also showed co-resistance to Cu, Zn and Mn but were sensitive to Hg and Cd. The selected bacterial isolates were resistant to ampicillin, penicillin G and polymyxin B, whereas fungal strains showed resistance to amphotericin B, nystatin and fusidic acid.

Intracellular degradation of poly(3-hydroxybutyric acid) accumulated by Azotobacter chroococcum MAL-201

Azotobacter chroococcum MAL-201 accumulates poly(3-hydroxybutyric acid) [P(3HB)] accounting 69% of cell dry weight (CDW) from glucose during growth in nitrogen-free Stockdale medium. Degradation of the accumulated polymer by the organism was studied under carbon-free medium following two-step cultivation method. P(3HB) content of cells decreased rapidly from 69% to 4.8% of CDW after 35 h under carbon-deprived condition. Autodigestion of P(3HB) was evident from the estimation of intracellular P(3HB) depolymerase (i-depolymerase) activity in cell-free extract using artificial P(3HB) granules as substrate. Polymer content decreased rapidly along with the increase in i-depolymerase activity and rate of polymer degradation when medium was supplemented with (NH4)2SO4 at 0.1% (w/v) level. However, the effects were reverse when organic nitrogenous substrate, beef extract at similar concentration was present in the medium. The optimum temperature and pH for i-depolymerase activity were 35 degrees C and 7.7 respectively. The oxygen-limiting condition (culture volume per flask volume, 50%) decreased 10.7% activity of i-depolymerase over control resulting a slow P(3HB) degradation. The presence of NaCl (6 x 10(3) microg/ml) showed a positive effect on i-depolymerase whereas EDTA (40 microg/ml) resulted in 20% less activity. Furthermore, the intracellular degradation of P(3HB) decreased the intrinsic viscosity, molecular weight and tensile strength of the accumulated polymer.

Aerobic chromate reduction by chromium-resistant bacteria isolated from serpentine soil

A group of 34 chromium-resistant bacteria were isolated from naturally occurring chromium percolated serpentine soil of Andaman (India). These isolates displayed different degrees of chromate reduction under aerobic conditions. One of the 34 isolates identified as Bacillus sphaericus was tolerant to 800 mgl(-1) Cr(VI) and reduced > 80% Cr(VI) during growth. In Vogel Bonner broth, B. sphaericus cells (10(10) cells ml(-1)) reduced 62% of 20mg l(-1) of Cr(VI) in 48h with concomitant discoloring of yellow medium to white one. Reduction of chromate was pronounced by the addition of glucose and yeast extract as electron donors. In the presence of 4.0 g l(-1) of glucose, 20mg l(-1) of Cr(VI) was reduced to 2.45mg l(-1) after 96h of incubation. Optimum pH and temperature for reduction were 6.0 and 25 degrees C, respectively. Increase in cell density and initial Cr(VI) concentration increased chromate reduction but was inhibited by metal ions like, Ni2+, Co2+, Cd2+ and Pb2+. Experiments with cell-free extracts indicated that the soluble fraction of the cell was responsible for aerobic reduction of Cr(VI) by this organism.

Gamma camera coincidence imaging with [18F]fluorodeoxyglucose in the pretreatment evaluation of patients with oesophageal cancer

This study investigated the role of [18F]fluorodeoxyglucose (FDG) dual-head gamma camera coincidence imaging (GCI) in the pretreatment evaluation of patients with oesophageal cancer. Twenty-two patients (20 men; mean age, 64 years) with untreated, biopsy proven squamous cell carcinoma of the oesophagus underwent positron emission tomography (PET) and GCI 1 and 3 h after a single injection of FDG, respectively. Computed tomography (CT) was performed within 2 weeks of the FDG imaging. The sensitivity of lesion detection was compared between GCI and PET. Regional (N) and distant (M) metastases detected by GCI were evaluated with reference to PET and CT. The staging obtained by each modality was also compared with pathological staging in nine patients who underwent surgery. FDG PET detected 22 primary tumours, 34 metastatic lymph nodes and four organ metastases. Of them, GCI detected all primary tumours, 24 (71%) metastatic lymph nodes, and none of the organ metastases. Lymph nodes missed by GCI were smaller in size and the majority of them were located in the thoracic region. GCI provided N and M staging identical to CT and PET in eight patients and improved staging over CT in four patients. On the other hand, GCI missed metastases detected by both PET and CT in five patients. The addition of GCI to CT could improve detection of patients with metastasis to 82% (18/22) compared with 64% (14/22) detected by CT alone. In patients with pathological staging (n = 9), GCI could influence management changes in two patients (22%). In conclusion, FDG GCI has a role that is complementary to CT in the initial staging of patients with oesophageal cancer, and due to the additional detection of nodal metastasis, GCI can provide staging information, which may influence changes in management.

Induction of mutation in Azotobacter chroococcum MAL-201 for improvement of P(3HB) production

Azotobacter chroococcum MAL-201 (MTCC 3853), a poly-3-hydroxybutyric acid [P(3HB)] producing organism was subjected to mutagenesis by UV-irradiation and N'-methyl-N'-nitro-N'-nitrosoguanidine (MNNG). A sharp decline in survival percentage of treated cells both in UV (1.2% at 20 sec. exposure) and in MNNG ((0.26% at 30 microg/ml) suggest high degree of sensitivity of the isolate to these mutagens. A total of 124 mutant colonies were isolated from viable population based on their morphological features, antibiotic resistance and dependence on exogenous organic nitrogenous substances. Nature of mutants were confirmed by replica plating and growth on antibiotic and organic nitrogen supplemented Norris agar medium. Majority of mutants were devoid of exopolysaccharide, dependent on organic nitrogen and with weak P(3HB) content. The mutant strain, UC-220, a nitrogen-dependent, chloramphenicol-resistant mutant showed an enhancement of more than 10% (w/w) P(3HB) production compared to that of wild type strain when grown under identical conditions.

Impaired cardiac response to exercise in post-menopausal women: relationship with peripheral vascular function

Endothelial dysfunction has been demonstrated in post-menopausal women. To assess the relationship between peripheral vascular reserve and cardiac function during exercise in post-menopausal women, 91 subjects, who had no ischaemic findings on myocardial SPECT, were assigned to four groups: pre-menopausal women (n=13), post-menopausal women (n=33), younger men aged < or =50 years (n=10), and older men aged >50 years (n=35). First-pass radionuclide angiography was performed before and during bicycle exercise to calculate ejection fraction (EF) and peripheral vascular resistance (VR). There were no differences in haemodynamic variables among the groups at baseline. The per cent increase in EF=(exercise EF - resting EF)x100/resting EF, and the per cent decrease in VR=(resting VR - exercise VR)x100/resting VR were depressed in the post-menopausal women (0.4+/-2% and 35+/-3%, respectively) compared to the pre-menopausal women (10+/-3% and 47+/-3%, respectively; P<0.05 each). Although the age dependent impairment is thought to cause this depression, neither the per cent increase in EF nor the per cent decrease in VR in the older men was significantly different from that in the younger men. Post-menopausal women exhibited depressed cardiac function during exercise, which may be related to the impairment of peripheral vascular function after menopause.

Left ventricular mass index measured by quantitative gated myocardial SPECT with 99mTc-tetrofosmin: a comparison with echocardiography

OBJECTIVE

Left ventricular mass is an important determinant of diagnosis and prognosis in patients with heart disease. The aim of the present study was to validate measurement of the left ventricular mass index (LVMI) by quantitative gated myocardial SPECT (QGS) with 99mTc-tetrofosmin by comparing it with echocardiography.

METHODS

QGS and M-mode echocardiography (Echo) were performed within one month of each other in 179 patients. M-mode echocardiography was carried out according to Devereux's method. QGS images were acquired one hour after injection of 99Tc-tetrofosmin at rest. Myocardial volume was defined as the volume between the endocardial and epicardial surface in the end-diastolic phase. LVMI (g/m2) was defined as myocardial volume divided by myocardial specific density and corrected for body surface area. QGS LVMI measurements were performed twice by the same observer and independently by two different observers. Regional hypoperfusion in the group of patients with old myocardial infarction (n = 26) was evaluated semiquantitatively on the basis of the total defect score on the resting 99mTc-tetrofosmin SPECT images.

RESULTS

Among the patients as a whole QGS LVMI was significantly correlated with Echo LVMI (r = 0.96, p < 0.001). Intra-observer and inter-observer analyses showed significant reproducibility (r = 0.99 and r = 0.98, respectively, p < 0.001). In the patients with old myocardial infarction, but QGS LVMI was significantly lower than Echo LVMI (p < 0.001), and the magnitude of the underestimation was closely related to the severity of the perfusion defect on the resting SPECT images.

CONCLUSIONS

Measurements of LVMI by 99mTc-tetrofosmin QGS are reproducible and consistent with echocardiograpic estimates. Underestimation in patients with severe perfusion defects must be taken into consideration.

Growth-associated production and characterization of poly (3-hydroxybutyric acid) of Azotobacter beijerinckii DAR-102

Production of poly (3-hydroxybutyric acid) [P(3HB)] by Azotobacter beijerinckii DAR-102 isolated in this laboratory has been optimized under batch-culture. The accumulatad polymer attained 58% of cell dry mass during mid-stationary phase with an yield of 0.58 g/l when grown in nitrogen-free medium. The optimum concentration of glucose and fructose for P(3HB) production was 3% (w/v) and 2% (w/v) respectively while that of casamino acid and tryptose was 0.1% (w/v). Phosphate at a concentration suboptimal for growth and limitation of oxygen in the medium favoured P(3HB) accumulation. The production of P(3HB) was maximum with an inoculum dose of 4% (v/v). The accumulated polymer was isolated by direct chloroform extraction of the dry cell mass and purified by precipitation with diethyl ether. The purified polymer has been characterized in terms of its solubility properties, melting temperature, and UV-, IR- and NMR-spectroscopic analyses.

Prolonged diastolic dysfunction following exercise induced ischaemia: a gated myocardial perfusion SPECT study

Prolonged impairment of left ventricular (LV) systolic function following exercise induced ischaemia has been well demonstrated. The objective of this study was to examine the effect of exercise induced ischaemia on the post-stress LV diastolic function in patients with coronary artery disease (CAD). Seventy-four subjects with known or suspected CAD underwent gated myocardial single photon emission computed tomography (SPECT) 1 h after administration of 99mTc tetrofosmin according to a standard same day exercise rest protocol. LV volumes and ejection fractions (LVEFs) were determined by the Cedars-Sinai program. Fourier transformation of the gated SPECT volume curve was performed retaining the fourth order harmonics, and peak filling rate (PFR) and time-to-PFR (TPFR) were calculated from the derivative curve. In patients with exercise induced ischaemia (n =26), 1 h post-stress PFR (2.66+/-0.75 s(-1)) and TPFR (119+/-12 ms) were significantly impaired in comparison to the resting PFR (3.06+/-0.74 s; P=0.0002) and TPFR (114+/-10 ms; P=0.03), respectively. In normal subjects (n =26) and in patients with infarction (n =22), the post-stress indices were similar to the resting values. When reduction of PFR or LVEF greater than the variability (2SD) of differences between the post-stress and resting values in the normal group was defined as significant impairment, six of the 26 ischaemic patients (23%) had such changes in PFR. All these patients exhibited severe ischaemia and five of them had simultaneous systolic impairment. Only one (4%) of the normal subjects and none of the patients in the infarction group showed such impairments. Stepwise logistic regression analysis of stress, scan and coronary variables revealed that the summed reversibility score, a scintigraphic index of ischaemic severity, was the only determinant of post-stress changes in LVEF and PFR. In conclusion, exercise induced LV diastolic impairment persists for a prolonged period after resolution of the ischaemic episode. The incidence and magnitude of the diastolic impairment are determined by the severity of the exercise provoked ischaemia.

Characteristics of regional myocardial stunning after exercise in gated myocardial SPECT

BACKGROUND

A number of studies have demonstrated prolonged left ventricular (LV) global dysfunction after exercise-induced ischemia in gated myocardial single photon emission tomography (SPECT) as a manifestation of exercise-induced stunning. This study investigated the residual effects of exercise on postexercise LV regional function and its implications on the detection of stunning in gated SPECT.

METHODS AND RESULTS

Fifty-three subjects with known or suspected coronary artery disease and 10 control subjects underwent myocardial SPECT according to a same-day exercise-rest protocol. Both postexercise and resting images were gated and acquired 1 hour after injection of technetium 99m tetrofosmin. The LV global ejection fraction and segmental systolic wall thickening were quantitated with the use of an automatic program. Segmental perfusion was assessed semiquantitatively on summed nongated tomograms. Wall thickening index (WTI), the ratio of systolic wall thickening of a segment to that of a corresponding control segment, was significantly lower after exercise than at rest in the reversible defect (RD) segments (0.66 +/- 0.24 vs 0.78 +/- 0.24; P <.0001). In patients with exercise-induced ischemia, the difference in WTI between rest and after exercise was significantly greater in the RD segments, which represented ischemia, than in the non-RD segments. Postexercise WTIs were not different from the resting values in subjects with no perfusion abnormalities or who had fixed defects (infarction). Significant postexercise dysfunction was present in 44% of the RD segments, compared with 5% of the normal and 3% of the fixed defect segments. Postexercise segmental dysfunction was correlated with the segmental reversibility score, the difference in defect scores between exercise and rest images (n = 82, Spearman rank correlation coefficient = -0.78, P <.0001). Among 19 patients with ischemia, 9 (47%) exhibited concurrent segmental and global dysfunction, but segmental dysfunction persisted in the absence of global dysfunction in 4 additional patients (21%).

CONCLUSIONS

Significant postexercise LV regional dysfunction, consistent with the concept of stunning, occurs in the region of severe ischemia. The incidence and magnitude of regional stunning are determined by the severity of ischemia. For the detection of stunning in gated SPECT, LV regional dysfunction may be more sensitive than global dysfunction.

Myocardial viability assessment with gated SPECT Tc-99m tetrofosmin % wall thickening: comparison with F-18 FDG-PET

OBJECT

This study was designed to assess the value of gated SPECT Tc-99m-tetrofosmin (TF) wall thickening (WT) in addition to TF exercise (Ex)/rest myocardial SPECT, in comparison with F-18 fluorodeoxyglucose (FDG)-PET.

METHODS

The study population consisted of 33 patients with old myocardial infarction (27 men and 6 women; mean age, 62 +/- 8 years old). All patients underwent Ex/rest TF SPECT and glucose loading FDG-PET. Polar map images of Ex/rest TF were generated and divided into 24 segments for further analysis. We classified LV segments according to the exercise-rest perfusion scintigraphy. LV segments with less than 70% of the maximum TF activity on the exercise image were defined as stress-induced defects. Among these, the segments whose TF activity increased by 10% from exercise to rest images or exceeded 70% of the maximum uptake were defined as reversible (viable) defects. The remaining defects on the rest image were irreversible (non-viable) defect segments, and were considered for viability study on the basis of %WT. %WT was calculated according to the standard method: [(counts ES - counts ED)/counts ED] x 100. A viable segment on gated SPECT was defined as a segment whose %WT exceeded the lower limit of the normal value (mean - SD). PET viability was defined as FDG uptake exceeding 50% of the maximum count.

RESULTS

Among the 792 segments evaluated in the 33 patients studied, there were 689 PET viable segments. Of the 689 segments analyzed, 198 (29%) were identified as having defects on Ex images. Among these defects, 55 (8%) were reversible or partially reversible, as evidenced by rest images, and 143 (21%) were irreversible. Of the irreversible segments on Ex/rest images, 106 (15%) demonstrated no apparent WT by gated TF SPECT, whereas 37 (6%) segments with irreversible defects did have apparent WT. Overall, the sensitivity of Ex/rest TF perfusion imaging was 79%. Sensitivity was improved from 79% to 85% by combining %WT and perfusion data, but specificity was reduced from 70% to 56%.

CONCLUSION

%WT evaluated from gated TF imaging enhanced myocardial viability assessment in comparison with FDG-PET.

Effects of iterative reconstruction on image contrast and lesion detection in gamma camera coincidence imaging in lung and breast cancers

To investigate the effects of iterative reconstruction in 18F-fluorodeoxyglucose (FDG) gamma camera coincidence imaging (GCI), image contrast and visual detection obtained by using the iterative ordered-subsets expectation maximization (OSEM) reconstruction, in a phantom and in patients with lung cancer and breast cancer, were compared with those obtained by using the conventional filtered backprojection (FBP) reconstruction. Images of a cylindrical phantom containing hot spheres of various sizes (10-38 mm) were acquired by positron emission tomography (PET) and GCI at various sphere-to-background activity ratios. Forty-one consecutive patients with biopsy-proven cancer of lung (n = 20) and breast (n = 21) underwent PET and GCI on the same day after intravenous injection of 370 MBq of FDG. GCI images reconstructed by the OSEM and the FBP were compared. FDG PET was considered as the standard of reference. In GCI phantom images, OSEM yielded better contrast and signal-to-noise ratio (SNR) than FBP over the range of sphere sizes. Attenuation correction improved both the image measures and sphere detection obtained by the OSEM in GCI. In the study involving patients, FDG PET depicted 41 primary tumours and 25 metastatic lymph nodes. All of the tumours >2 cm in diameter (n = 25), six of the nine tumours 1.5-2.0 cm in diameter (67%), two of seven tumours <1.5 cm in diameter (29%), and 20 metastatic lymph nodes (80%) were detected in attenuation uncorrected GCI reconstructed by the OSEM as well as the FBP. The undetected lesions in GCI were identical between the OSEM and the FBP reconstructions. OSEM yielded significantly greater tumour-to-background (T/B) ratios and lower noise than FBP in GCI (T/B ratios, 4.1+/-3.2 vs 3.7+/-2.7, P = 0.02; noise, 0.09+/-0.04 vs 0.14+/-0.05, P<0.0001). In conclusion, OSEM yielded better image contrast and less noise than the FBP in GCI, but the lesion detection obtained by the OSEM and the FBP in attenuation uncorrected GCI in patients with lung cancer and breast cancer were similar. Phantom data suggest the potential of OSEM for improving lesion detection in GCI after attenuation correction.

Feasibility of a short acquisition protocol for whole-body positron emission tomography with fluorine-18 fluorodeoxyglucose

The conventional protocol for whole-body positron emission tomography (PET) with fluorine-18 fluorodeoxyglucose (FDG) requires a total acquisition time of 40-60 min, which is inconvenient for many oncological patients owing to fatigue and discomfort. This study examined the feasibility of a short protocol for whole-body PET. A phantom containing six "hot" spheres of gradually increasing diameter (10-38 mm) was imaged using a dedicated PET scanner for 20, 40, 60, 80, 120 and 600 s at various count rates. Thirty-four patients with various neoplasms underwent whole-body emission scans for 1 min per bed position 1 h after intravenous injection of 370 MBq of FDG (short protocol). A standard simultaneous transmission-emission acquisition for 10 min per bed position was performed thereafter. The images were reconstructed using an iterative algorithm. At a count rate of 40 kcps, which is close to the average count rate obtained in a whole-body FDG PET study, the 60-s image visualised five spheres, of which the smallest was 13 mm in size. Despite the better image quality, lesion detection was not improved in images acquired for more than 60 s (80-600 s). Only three of the six spheres could be detected in images acquired for less than 60 s. In the patient study, the standard protocol visualised 120 tumour lesions, of which 93 (78%) could be detected using the short protocol. Among the non-visualised lesions, 22 (82%) were < or =1.5 cm in size and 17 (63%) were lymph nodes. It is concluded that the proposed short protocol for whole-body FDG PET has a reasonably high detection rate and may be suitable for patients who are unable to undergo scanning for a prolonged period. It may also be useful as a pre-scan guide before a standard whole-body acquisition.

Clinical value of lung uptake of iodine-123 metaiodobenzylguanidine (MIBG), a myocardial sympathetic nerve imaging agent, in patients with chronic heart failure

This study investigated the clinical value of I-123 MIBG pulmonary accumulation and washout in patients with chronic heart failure (CHF). Nineteen patients with CHF and 15 normal volunteers (NL) were included. The uptake ratio of heart to mediastinum (H/M), that of lung fields to mediastinum (L/M), and washout rate (WR) of the heart and lung fields were calculated in anterior planar images and compared with results of echocardiography and cardiac catheterization. In the CHF group, the lung uptake in delayed images increased and lung WR was decreased, suggesting pulmonary endothelial lesions. Furthermore, there was a negative correlation between right and left lung WR and pulmonary arterial diastolic pressure (PA(D)) and pulmonary arterial systolic pressure (PA(s)) in the CHF group. Since the WR of MIBG reflected PA, it may be used as an index of severity of cardiac dysfunction.

Degradation of microbial polyester poly(3-hydroxybutyrate) in environmental samples and in culture

Poly(3-hydroxybutyrate) [P(3HB)] test-pieces prepared from the polymer produced by Azotobacter chroococcum were degraded in natural environments like soil, water, compost and sewage sludge incubated under laboratory conditions. Degradation in terms of % weight loss of the polymer was maximum (45%) in sewage sludge after 200 days of incubation at 30 degrees C. The P(3HB)-degrading bacterial cultures (36) isolated from degraded test-pieces showed different degrees of degradation in polymer overlayer method. The extent of P(3HB) degradation increases up to 12 days of incubation and was maximum at 30 degrees C for majority of the cultures. For most efficient cultures the optimum concentration of P(3HB) for degradation was 0.3% (w/v). Supplementation of soluble carbon sources like glucose, fructose and arabinose reduced the degradation while it was almost unaffected with lactose. Though the cultures degraded P(3HB) significantly, they were comparatively less efficient in utilizing copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate [P(3HB-co-3HV)].

Enhanced UV sensitivity of Thiobacillus ferrooxidans resulting from caffeine and acriflavine treatment of irradiated cells

This study was aimed at identifying the roles of caffeine and acriflavine, two repair inhibitors, on UV sensitivity of iron-oxidizing Thiobacillus ferrooxidans ATCC 13728. The UV-dose response survival curve was inflected in nature, suggesting the population heterogeneity of the isolate. Caffeine and acriflavine potentiated the UV-induced killing of the organism. With the increase in concentrations of these compounds, the extent of survival decreased. Similarly, the inhibitory effects of caffeine and acriflavine increased with the increase in dose of UV-irradiation. The cells irradiated with 10 s (equivalent to 5.6 x 10(-5) J/m2/s) of UV-exposure tended to become resistant to the inhibitory effects of caffeine and acriflavine, as evidenced by the time course study of recovery. The cells appear to stage a dramatic recovery from UV damage in the presence of caffeine (3.0 mg/ml) and acriflavine (20 microg/ml) over a period of 25-30 h and 35-40 h respectively, when grown in the presence of energy sources.

Production of an antifungal antibiotic by Streptomyces aburaviensis 1DA-28

A broad-spectrum antifungal Streptomyces isolate, 1DA-28, from Indian soil has been characterized and identified as Streptomyces aburaviensis var. ablastmyceticus (MTCC 2469). Nutritional and cultural conditions for the production of antibiotic by this organism under shake-flask conditions have been determined. Antibiotic production in synthetic medium reached the maximum on the 5th day of incubation at 30 degreesC. Glucose and starch were found to be the best carbon sources while NH4NO3 was preferred as nitrogen source. Optimum temperature and pH for antibiotic production were 32 degreesC and 7.4, respectively. Phosphate at a concentration sub-optimal for growth enhanced antibiotic production. Supplementation of medium with casein hydrolysate improved both growth and antibiotic titre but yeast extract exhibited marked inhibition.

Synthesis and accumulation of poly(3-hydroxybutyric acid) by Rhizobium sp

Forty-two Rhizobium strains obtained from different culture collections were evaluated quantitatively for poly(3-hydroxy-butyric acid) [PHB] production in shake flask culture. The majority of the strains produced the maximum amount of PHB during the late exponential or stationary phase of growth. Synthesis and accumulation of PHB in different species of Rhizobium were found to vary between 1-38% of their dry biomass. Growth and PHB production by the Rhizobium strain TAL-640 were greatly influenced by the C-source and D-mannitol was fundamental to both processes. The identity and purity of PHB isolated from TAL-640 have also been confirmed by UV-, IR- and 1H-NMR spectroscopic analyses.

Kramers problem for a polymer in a double well

We consider a long chain molecule, initially confined to the metastable side of a biased double well potential. It can escape from this side to the other by the motion of its N segments across the barrier. We assume that the length of the molecule is much larger than the width w of the barrier. The width w is taken to be sufficiently large that a continuum description is applicable to even the portion over the barrier. We use the Rouse model and analyze the mechanism of crossing the barrier. There can be two dominant mechanisms: end crossing and hairpin crossing. We find the free energy of activation for the hairpin crossing to be two times that for end crossing. The pre-exponential factor for hairpin crossing is proportional to N, while it is independent of N for end crossing. In both cases, the activation energy has a square root dependence on the temperature T, leading to a non-Arrhenius form for the rate. We also show that there is a special time dependent solution of the model, which corresponds to a kink in the chain, confined to the region of the barrier. The movement of the polymer from one side to the other is equivalent to the motion of the kink on the chain in the reverse direction. If there is no free energy difference between the two sides of the barrier, then the kink moves by diffusion and the time of crossing t(cross) approximately N(2)/T(3/2). If there is a free energy difference, then the kink moves with a nonzero velocity from the lower free energy side to the other, leading to t(cross) approximately N/sqrt[T]. We also discuss the applicability of the mechanism to the recent experiments of Kasianowicz [Proc. Natl. Acad. Sci. USA 93, 13 770 (1996)], where DNA molecules were driven through a nanopore by the application of an electric field. The prediction that t(cross) approximately N is in agreement with these experiments. Our results are in agreement with the recent experimental observations of Han, Turner, and Craighead [Phys. Rev. Lett. 83, 1688 (1999)]. We also consider the translocation of hydrophilic polypeptides across hydrophobic pores, a process that is quite common in biological systems. Biological systems accomplish this by having a hydrophobic signal sequence at the end that goes in first. We find that for such a molecule, the transition state resembles a hook, and this is in agreement with presently accepted view in cell biology.

Assessment of left ventricular function by gated myocardial perfusion and gated blood-pool SPECT: can we use the same reference database?

The purpose of this study was to compare left ventricular (LV) volume and ejection fraction (LVEF) measurements obtained with electrocardiographic gated single-photon emission computed tomographic (SPECT) myocardial perfusion imaging (GS-MPI) with those obtained with gated SPECT cardiac blood-pool imaging (GS-pool). Fifteen patients underwent GS-MPI with technetium-99m-tetrofosmin and GS-pool with technetium-99m-erythrocyte, within a mean interval of 8 +/- 3 days. Eight patients had suspected dilated cardiomyopathy and seven patients had angiographically significant coronary artery disease. End-diastolic volume (EDV), end-systolic volume (ESV) and LVEF measurements were estimated from GS-MPI images by means of Cedars-Sinai automatic quantitative program and from GS-pool images by the threshold technique. Mean differences between GS-MPI and GS-pool in EDV, ESV and LVEF measurements were -2.8 +/- 10.5 ml [95% confidence interval (CI): -8.6 +/- 3.0 ml], 2.6 +/- 7.3 ml (CI: -1.4 +/- 6.6 ml) and -2.3 +/- 5.1% (CI: -5.1 +/- 0.6%), respectively. No significant difference in the mean differences from 0 was found for EDV, ESV or LVEF measurements. Bland-Altman plots revealed no trend over the measured LV volumes and LVEF. For all parameters, regression lines approximated lines of identity. The excellent agreement between GS-MPI and GS-pool measurements suggests that, for estimation of LV volumes and LVEF, these two techniques may be used interchangeably and measurements by one method can serve as a reference for the other.

Micropropagation of sweet orange, Citrus sinensis Osbeck. for the development of nucellar seedlings

Protocol for micropropagation of elite plants of sweet orange (Citrus sinensis) through nucellar embryo culture has been standardized. Three to four nucellar embryos and a zygotic embryo could be excised from a single mature seed and successfully generated as healthy plants in basal MS medium. MS medium supplemented with NAA (1 mg/L) or 2, 4.D (1 mg/L) promoted callus development in both nucellar and zygotic embryos. GA3 (1 mg/L) enriched medium induced plantlets initiation but their growth was very poor. No significant differences were observed between initial growth patterns of nucellar and zygotic seedlings developing from the same ovule. Five to six shoots were obtained from collar region of both category of embryos in MS medium supplemented with BAP (1 mg/L) within 60 days of inoculation. The number of plantlets were almost doubled after their transfer in the same medium and culture for another 30 days. Higher doses of BAP resulted in initiation of callus directly from the embryos. The regenerated shoots (2-3 cm) could be rooted in MS medium supplemented with either only NAA (0.75 mg/L) or NAA (0.50 mg/L) and IBA (2.0 mg/L). A number of plantlets could be obtained from a nucellar embryo grown shoot within a limited time period.

Left ventricular volumes and ejection fraction calculated from quantitative electrocardiographic-gated 99mTc-tetrofosmin myocardial SPECT

We compared the left ventricular (LV) end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (LVEF) as calculated by Cedars automated quantitative gated SPECT (QGS) to those determined by first-pass radionuclide angiography (FPRNA) and contrast left ventriculography (LVG) in a group of 21 patients (mean age 61.4 +/- 9.2 y).

METHODS

A total of 740 MBq 99mTc-tetrofosmin was administered rapidly into the right cubital vein at rest, and FPRNA was performed using a multicrystal gamma camera. One hour after injection, QGS was performed with a temporal resolution of 10 frames per R-R interval. LVG was performed within 2 wk.

RESULTS

The EDV, ESV and LVEF calculated by QGS were highly reproducible (intraobserver, r = 0.99, r = 0.99 and r = 0.99, respectively; interobserver, r = 0.99, r = 0.99 and r = 0.99, respectively; P < 0.01) and were more consistent than those determined by FPRNA (intraobserver, r = 0.97, r = 0.95 and r = 0.93, respectively; interobserver, r = 0.86, r = 0.96 and r = 0.91, respectively; P < 0.01). There was a good correlation between EDV, ESV and LVEF by FPRNA and those by LVG (r = 0.61, r = 0.72 and r = 0.91, respectively; P < 0.01), and there was an excellent correlation between QGS and LVG (r = 0.73, r = 0.83 and r = 0.87, respectively; P < 0.01). The mean EDV by QGS (100 +/- 11.3 mL) was significantly lower than by FPRNA (132 +/- 16.8 mL) or LVG (130 +/- 8.1 mL), and the mean ESV by QGS (53.8 +/- 9.3 mL) was lower than by FPRNA (73.0 +/- 13.3 mL). Ejection fraction values were highest by LVG (57.1% +/- 3.2%), then QGS (51.8% +/- 3.0%) and FPRNA (48.9% +/- 2.4%).

CONCLUSION

QGS gave more reproducible results than FPRNA. LV volumes and LVEF calculated by QGS correlated well to those by LVG.

Accumulation of poly (3-hydroxybutyric acid) by some soil Streptomyces

In a limited-scale survey, 55 soil streptomycetes were screened for the accumulation of poly (3-hydroxybutyrate) [PHB]. Only 18% of the isolates accumulated PHB ranging between 1.9-7.8% of the dry biomass. The promising isolate DBCC-719, identified as Streptomyces griseorubiginosus, accumulated PHB amounting to 9.5% of the mycelial dry mass in the early stationary phase when grown in chemically defined medium with 2% (wt/vol) glucose as the sole source of carbon. Nitrogen-limiting conditions were inhibitory to growth and PHB accumulation. The isolated polymer was highly soluble in chloroform, gave a sharp peak at 235 nm on digestion with concentrated H(2)SO(4), and had a characteristic infrared spectrum.

Chromium-resistant soil actinomycetes: their tolerance to other metals and antibiotics

Chromium occurs widely in most soils, but generally in trace amounts. Actinomycetes, one of the important components of the microbial population in soils interact with a variety of metals including chromium. This study was aimed to evaluate the tolerance of soil actinomycetes to Cr6+, other metals and antibiotics. Thirty-two actinomycete isolates were screened for their tolerance to Cr6+ on tryptone yeast extract agar medium supplemented with Cr6+ at concentrations ranging from 100 to 2000 micrograms ml-1. Thirteen Cr-tolerant isolates were selected on the basis of their growth at the highest concentration, but their performance was not satisfactory in Cr6+ containing liquid salts medium. Resistance of these isolates to other metals and antibiotics was assessed using agar-cup assay and disc diffusion technique, respectively. The sequence of metal toxicity for the actinomycete isolates was in the order Hg2+ > Ni2+ > Cu2+ > Co2+ > Cd2+, but the Cr6+ resistance of the isolates could not be correlated with their antibiotic-resistance profile.

Exercise-induced stunning continues for at least one hour: evaluation with quantitative gated single-photon emission tomography

To elucidate the after-effect of exercise on left ventricular (LV) function, end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (LVEF) were evaluated at 1 h after exercise and at rest by technetium-99m tetrofosmin gated myocardial single-photon emission tomography (SPET) using an automated program in 53 subjects. The subjects were grouped as follows: normal scan (n = 16), ischaemia (n = 19) and infarction (n = 18), based on the interpretation of perfusion images. Postexercise LVEF did not differ from resting LVEF in the groups with normal scan and infarction. In patients with ischaemia, postexercise EDV (90+/-17 ml, mean +/-SD) and ESV (44+/-15 ml) were significantly higher than EDV (84+/-15 ml, P = 0.001) and ESV (36+/-14 ml, P<0.0005) at rest. LVEF was significantly depressed 1 h after exercise (53%+/-9% vs 58%+/-9%, P<0.0001). In ischaemic patients with depressed postexercise LVEF, LVEF difference between rest and postexercise showed a significant correlation with the sum of defect scores, which were reversible from exercise to rest perfusion images (r = 0.92, P<0.0001). These results indicate that exercise-induced LV dysfunction (myocardial stunning) continues for at least 1 h in ischaemic patients and that the extent of LVEF depression is determined by the severity of ischaemia.

Exopolysaccharide production by some rhizobium strain in culture

Eight Rhizobium strains were screened for exopolysaccharide production during growth in yeast extract mannitol medium. A strain of Rhizobium loti produced more than 250 mg of exopolysaccharide/100 ml of culture during the stationary phase of growth. Exopolysaccharide production was favoured by maltose and mannitol but N2 supplementation could not affect the production siginificantly. Preliminary studies indicate that the polymer contains 16% protein and 73.5% carbohydrate being composed of glucose, galactose and glucuronic acid.