Economics of place-based monitoring under the safe drinking water act, part II: design and development of place-based monitoring strategies

The goals of environmental legislation and associated regulations are to protect public health, natural resources, and ecosystems. In this context, monitoring programs should provide timely and relevant information so that the regulatory community can implement legislation in a cost-effective and efficient manner. The Safe Drinking Water Act (SDWA) of 1974 attempts to ensure that public water systems (PWSs) supply safe water to its consumers. As is the case with many other federal environmental statutes, SDWA monitoring has been implemented in relatively uniform fashion across the United States. In this three part series, spatial and temporal patterns in water quality data are utilized to develop, compare, and evaluate the economic performance of alternative place-based monitoring approaches to current monitoring practice. Part II: Several factors affect the performance of monitoring strategies, including: measurable objectives, required precision in estimates, acceptable confidence levels of such estimates, available budget for sampling. In this paper, we develop place-based monitoring strategies based on extensive analysis of available historical water quality data (1960-1994) of 19 Iowa community water systems. These systems supply potable water to over 350,000 people. In the context of drinking water, the objective is to protect public health by utilizing monitoring resources to characterize contaminants that are detectable, and are close to exceeding health standards. A place-based monitoring strategy was developed in which contaminants were selected based on their historical occurrence, rather than their appearance on the SDWA contaminant list. In a subset of the water systems, the temporal frequency of monitoring for one ubiquitous contaminant, nitrate, was tailored to patterns in its historical occurrence and concentration. Three sampling allocation models (linear, quadratic, and cubic) based on historic patterns in peak occurrence were developed and evaluated. Random and fixed-interval sampling strategies within the context of such models were also developed and evaluated. Strategies were configured to incorporate a variety of options for frequency and number of samples (depending on budget and the desired precision in estimate of peak concentrations).

Economics of place-based monitoring under the safe drinking water act, part III: performance evaluation of place-based monitoring strategies

The goals of environmental legislation and associated regulations are to protect public health, natural resources, and ecosystems. In this context, monitoring programs should provide timely and relevant information so that the regulatory community can implement legislation in a cost-effective and efficient manner. The Safe Drinking Water Act (SDWA) of 1974 attempts to ensure that public water systems (PWSs) supply safe water to its consumers. As is the case with many other federal environmental statutes, SDWA monitoring has been implemented in relatively uniform fashion across the USA. In this three part series, we present over 30 years of evidence to demonstrate unique patterns in water quality contaminants over space and time, develop alternative place-based monitoring approaches that exploit such patterns, and evaluate the economic performance of such approaches to current monitoring practice. Part III: Place-based (PBA) and current SDWA monitoring approaches were implemented on test datasets (1995-2001) from 19 water systems and evaluated based on the following criteria: percent of total detections, percent detections above threshold values (e.g. 20, 50, 90% of MCL), and cost. The PBA outperformed the current SDWA monitoring requirements in terms of total detections, missed only a small proportion of detections below the MCL, and captured all detections above 50% of the MCL. Essentially the same information obtained from current compliance monitoring requirements can be gained at approximately one-eighth the cost by implementing the PBA. Temporal sampling strategies were implemented on test datasets (1995-2001) from four water systems and evaluated by the following criteria: parameter estimation, percent deviation from "true" 90th, 95th, and 99th percentiles, and number of samples versus accuracy of the estimate. Non event-based (NEB) strategies were superior in estimating percentiles 1-50, but underestimated the higher percentiles. Event-based strategies were superior in estimating 95th and 99th percentiles, and required significantly fewer samples (than NEB strategies) to estimate the "true" 95th and 99th percentiles. Incorporation of place-based information significantly improves the performance of monitoring and temporal sampling strategies in the context of surface-influenced water systems in the state of Iowa. Application of similar methods to other areas and types of water systems would likely produce similar results. Compared to current SDWA monitoring, the place based approach allows for cost-effective, enhanced characterization of local contaminants of concern.

Functions of the type 1 BMP receptor Acvr1 (Alk2) in lens development: cell proliferation, terminal differentiation, and survival

PURPOSE

Bone morphogenetic protein (BMP) signaling is essential for the induction and subsequent development of the lens. The purpose of this study was to analyze the function(s) of the type 1 BMP receptor, Acvr1, in lens development.

METHODS

Acvr1 was deleted from the surface ectoderm of mouse embryos on embryonic day 9 using the Cre-loxP METHOD: Cell proliferation, cell cycle exit, and apoptosis were measured in tissue sections by immunohistochemistry, immunofluorescence, and TUNEL staining.

RESULTS

Lenses formed in the absence of Acvr1. However, Acvr1(CKO) (conditional knockout) lenses were small. Acvr1 signaling promoted proliferation at early stages of lens formation but inhibited proliferation at later stages. Inhibition of cell proliferation by Acvr1 was necessary for the proper regionalization of the lens epithelium and promoted the withdrawal of lens fiber cells from the cell cycle. In spite of the failure of all Acvr1(CKO) fiber cells to withdraw from the cell cycle, they expressed proteins characteristic of differentiated fiber cells. Although the stimulation of proliferation was Smad independent, the ability of Acvr1 to promote cell cycle exit later in development depended on classical R-Smad-Smad4 signaling. Loss of Acvr1 led to an increase in apoptosis of lens epithelial and fiber cells. Increased cell death, together with the initial decrease in proliferation, appeared to account for the smaller sizes of the Acvr1(CKO) lenses.

CONCLUSIONS

This study revealed a novel switch in the functions of Acvr1 in regulating lens cell proliferation. Previously unknown functions mediated by this receptor included regionalization of the lens epithelium and cell cycle exit during fiber cell differentiation.

Oxygen distribution in the rabbit eye and oxygen consumption by the lens

PURPOSE

Excessive exposure to oxygen has been proposed to be a risk factor for nuclear cataracts. For a better understanding of the metabolism of oxygen in the eye, oxygen distribution was mapped in the intraocular fluids, and the rate of oxygen consumption by the lens in rabbits breathing different levels of oxygen was calculated.

METHODS

Young albino rabbits were anesthetized, intubated, and exposed to normoxic, hypoxic, or hyperoxic conditions. The hemoglobin saturation of the blood was monitored with a pulse oximeter, and arterial oxygen levels were measured with a blood gas analyzer. A fiberoptic optical oxygen sensor (optode) was used to determine oxygen levels in different regions of the eye. Oxygen flux across the posterior of the lens was calculated from the measured oxygen gradients in the vitreous chamber.

RESULTS

Oxygen levels in the ocular fluids changed markedly when rabbits breathed air made hypoxic or hyperoxic. Oxygen levels were highest near the retinal vasculature, the iris vasculature, and the inner surface of the central cornea. Compared with nearby regions, oxygen levels were decreased in the aqueous humor closest to the pars plicata of the ciliary body and near the anterior chamber angle. Oxygen levels were generally lower closer to the lens. From the oxygen gradients in the vitreous body, oxygen consumption by the posterior half of the lens was calculated to be 0.2 to 0.4 microL/h under normoxic conditions. Oxygen consumption by the posterior of the lens increased in proportion to the amount of oxygen supplied.

CONCLUSIONS

Intraocular oxygen is mostly derived from the retinal and iris vasculature and by diffusion across the cornea. Freshly secreted aqueous humor and the aqueous humor in the anterior chamber angle are relatively depleted of oxygen. The marked increase in oxygen consumption that occurs when the lens is exposed to increased oxygen is likely to result in the production of higher levels of reactive oxygen species and may provide a link between elevated oxygen levels and the risk of nuclear cataracts.

Two cases of subungual glomus tumor

Glomus tumors are uncommon, small, painful, and usually benign hamartomas arising from the arterial end of the glomus body. They often present early in the subungual stage because of intense pain. Two female patients with subungual glomus tumor are reported here. The intense pain associated with this tumor had led to disuse atrophy of the upper limb in one case. Hildreth's sign and Love's test were positive in both, but imaging did not help in preoperative diagnosis. Tumors were resected by transungual approach, leaving a 3-mm-wide margin. There was no recurrence after 1-year follow-up in both instances.

Immune cascade of Spodoptera litura: Cloning, expression, and characterization of inducible prophenol oxidase

Haemolymph associated phenol oxidase is a critical component of invertebrate immune reaction and cuticle sclerotization. Phenol oxidase catalyses the conversion of mono-phenols to diphenols and quinones which finally leads to melanin formation. We have cloned the c-DNA encoding phenol oxidase from the haemocytes of Spodoptera litura and expressed it in Escherichia coli. The encoding gene is 2452bp with an open reading frame of 2091 bp translating into a 697 amino acid protein. Multiple alignment analysis of the predicted protein sequence shows close homology to other lepidopeteran PPOII type genes. The transcription of the gene is induced upon microbial challenge of 6th instar larvae with E. coli and is unresponsive to injury. Cloning of the ORF of SLPPO in-frame in the E. coli expression vector pQE30 resulted in its expression. Enzymatic analysis of the recombinant protein reveals that the recombinant protein is catalytically active on 4-methyl pyrocatechol upon activation by cetyl pyridinium chloride.

Thrombectomy and distal protection devices

Visible distal embolization is a relatively rare complication during percutaneous coronary interventions but it may occur in 15-20% of angioplasties in saphenous vein grafts (SVG) and in thrombus containing lesions of native coronary arteries, especially in the setting of acute myocardial infarction (AMI). Mechanical thrombectomy devices and distal protection devices have been introduced to reduce the incidence of distal embolisation. Angiojet thrombectomy has shown positive outcomes in thrombus containing lesions when compared with intracoronary thrombolysis but a randomised trial failed to show benefit in the context of AMI. The X-Sizer, Excimer LASER and various simple aspiration thrombectomy catheters show promise in treatment of AMI with improvement shown in surrogate end-points such as resolution of ST-elevation but there have been no randomised trials large enough to demonstrate changes in hard clinical end-points. Distal protection devices have come to be routinely used during SVG treatment and, after the results of the SAFER and FIRE trials; they became a treatment recommendation in the recently issued European Society of Cardiology (ESC) guidelines. For AMI, these devices showed great promise in early single-centre studies which have been offset by the lack of clinical benefit in the multi-centre EMERALD trial. Proximal occlusion devices may further decrease the incidence of distal embolisation, especially in the treatment of totally occluded SVGs or native arteries, by reversing the blood flow and offering protection at a very early stage of the procedure before wire passage. Despite continuous technical improvement and a growing number of miniaturised thrombectomy devices and filters, because of the paucity of controlled large studies, it remains unclear whether these devices will remain limited to niche' applications or will become a regular companion to balloons and stents in mainstream angioplasty procedures.

Glutathione S -transferase T1 polymorphisms are associated with outcome in colorectal cancer

Colorectal cancer (CRC) remains a significant cause of mortality accounting for approximately 10% of all deaths from malignancy in the western world. Polymorphism in the glutathione S-transferase GSTT1 gene has been associated with CRC risk in some but not all studies. In this study, we examined associations between GSTT1 genotypes and CRC risk, and prognosis in 361 cases and 881 unrelated controls. GSTT1 null was associated with a small but significant increase in risk (P = 0.0006, odds ratio (OR) = 1.65, 95% confidence interval (CI) = 1.22-2.24). GSTT1 null was also associated with a significantly younger age at diagnosis (mean 65.2 years) compared with GSTT1 A (mean 67.6 years, P = 0.031). There were no significant associations between GSTT1 genotypes and clinical factors (e.g. Dukes stage, differentiation and tumour node metastasis classification) in the total case group. However, following stratification by age (<70 versus > or =70 years at diagnosis), in the patients diagnosed <70 years of age, GSTT1 null was more common in Dukes grade A/B tumours (P = 0.046), stage T1/T2 tumours (P = 0.053) and those with a pushing margin (P = 0.066). We also identified associations between GSTT1 null and increased prevalence of host lymphocyte response, particularly in the younger patients (P = 0.036). Furthermore, GSTT1 null was associated with improved survival in younger patients (P = 0.017, hazards ratio (HR) = 0.52, 95% CI = 0.31-0.89) but poorer survival in older patients (P = 0.017, HR = 1.89, 95% CI = 1.12-3.20). We proposed a model based on the dual functionality of GSTT1 to explain these contrasting results. We suggest that the null genotype is associated with improved immune response in younger patients, but poorer detoxification in older patients. These findings may also provide an explanation for the contrasting finding of other studies on the role of this gene in CRC.

Contributions by members of the TGFbeta superfamily to lens development

Members of the TGFbeta superfamily of growth and differentiation factors, including the TGFbeta, BMP, activin and nodal families, play important signaling roles throughout development. This paper summarizes some of the functions of these ligands in lens development. Targeted deletion of the genes encoding one of the BMP receptors, Alk3 (BMP receptor-1A), showed that signaling through this receptor is essential for normal lens development. Lenses lacking Alk3 were smaller than normal, with thin epithelial layers. The fiber cells of Alk3 null lenses became vacuolated and degenerated within the first week after birth. Lenses lacking Alk3 function were surrounded by abnormal mesenchymal cells, suggesting that the lenses provided inappropriate signals to surrounding tissues. Lens epithelial and fiber cells contained endosomes that were associated with activated (phosphorylated) SMAD1 and SMAD2. Endosomal localization of pSMAD1 was reduced in the absence of Alk3 signaling. The presence of pSMAD2 in lens fiber cell nuclei and the observation that the activin antagonist follistatin inhibited lens cell elongation suggested that an activin-like molecule participates in lens fiber cell differentiation. Lenses deficient in type II TGFbeta receptors were clear and had fiber cells of normal morphology. This suggests that TGFbeta signaling is not essential for the normal differentiation of lens fiber cells. The targeted deletion of single or multiple receptors of the TGFbeta superfamily in the lens should further characterize the role of these signaling molecules in lens development. This approach may also provide a useful way to define the downstream pathways that are activated by these receptors during the development of the lens and other tissues.

Molecular characterization of chitinase from polyphagous pest Helicoverpa armigera

Chitinase from a polyphagous pest, Helicoverpa armigera, has been cloned and expressed. The Helicoverpa chitinase cDNA is 2870 bp in length and contains an open reading frame of 1767 bp. The cDNA encodes a polypeptide of 588 residues with a predicted molecular weight of 66 kDa and a pI of 5.99. The polypeptide has distinct catalytic and substrate binding domains at the N- and the C termini, respectively. The two domains are held together by a proline, threonine rich linker region. The catalytic and the substrate binding domains shared a high level of homology with other lepidopteran chitinases, but the proline and threonine rich region is longer in H. armigera chitinase than in other lepidopteran chitinases. The transcription of chitinase at different developmental stages and in different tissues was analysed by RT-PCR. Chitinase transcript was found in the integument, gut, and fat bodies but was absent in the haemocytes. The levels of chitinase mRNA were abundant at the moulting stages and a basal level of transcript was maintained throughout the development of the insect. Interestingly, Western blot analysis of total proteins from the integument and the gut showed the presence of chitinase in the moulting stages but was absent in the intermoult periods, suggesting post-transcriptional control. The chitinase cDNA was expressed in bacteria and in insect cells. The insect cell expressed chitinase was glycosylated and catalytically active against the simple and complex substrates. The chitinase gene spans about 6.8 kb of genomic DNA and is organized into 10 exons and 9 introns. The 6.8 kb genomic clone of chitinase revealed a high degree of conservation in the position and size of the exons with other lepidopteran insects.

Scrub typhus: a case report

Fever with rash is a common cause for dermatological referral. The causes can range from viral to protozoal, bacterial or spirochaetal. A case of rickettsial fever is reported.

A constitutively expressed 36 kDa exochitinase from Bacillus thuringiensis HD-1

A 36 kDa chitinase was purified by ion exchange and gel filtration chromatography from the culture supernatant of Bacillus thuringiensis HD-1. The chitinase production was independent of the presence of chitin in the growth medium and was produced even in the presence of glucose. The purified chitinase was active at acidic pH, had an optimal activity at pH 6.5, and showed maximum activity at 65 degrees C. Of the various substrates, the enzyme catalyzed the hydrolysis of the disaccharide 4-MU(GlnAc)(2) most efficiently and was therefore classified as an exochitinase. The sequence of the tryptic peptides showed extensive homology with Bacillus cereus 36 kDa exochitinase. The 1083 bp open reading frame encoding 36 kDa chitinase was amplified with primers based on the gene sequence of B. cereus 36 kDa exochitinase. The deduced amino-acid sequence showed that the protein contained an N-terminal signal peptide and consisted of a single catalytic domain. The two conserved signature sequences characteristic of family 18 chitinases were mapped at positions 105-109 and 138-145 of Chi36. The recombinant chitinase was expressed in a catalytically active form in Escherichia coli in the vector pQE-32. The expressed 36 kDa chitinase potentiated the insecticidal effect of the vegetative insecticidal protein (Vip) when used against neonate larvae of Spodoptera litura.

Recombinantly expressed isoenzymic aminopeptidases from Helicoverpa armigera (American cotton bollworm) midgut display differential interaction with closely related Bacillus thuringiensis insecticidal proteins

Several investigators have independently identified membrane-associated aminopeptidases in the midgut of insect larvae as the initial interacting ligand to the insecticidal crystal proteins of Bacillus thuringiensis. Though several isoenzymes of aminopeptidases have been identified from the midgut of an insect and their corresponding cDNA cloned, only one of the isoform has been expressed heterologously and studied for its binding to Cry toxins. Here we report the cloning and expression of two aminopeptidases N from Helicoverpa armigera (American cotton bollworm) (HaAPNs). The full-length cDNA of H. armigera APN1 (haapn1) is 3205 bp in size and encodes a 1000-amino-acid protein, while H. armigera APN2 (haapn2) is 3116 bp in size and corresponds to a 1012-amino-acid protein. Structurally these proteins show sequence similarity to other insect aminopeptidases and possess characteristic aminopeptidase motifs. Both the genes have been expressed in Trichoplusia ni (cabbage looper) cells using a baculovirus expression vector. The expressed aminopeptidases are membrane-associated, catalytically active and glycosylated. Ligand-blot analysis of both these aminopeptidases with bioactive Cry1Aa, Cry1Ab and Cry1Ac proteins displayed differential interaction. All the three toxins bound to HaAPN1, whereas only Cry1Ac interacted with HaAPN2. This is the first report demonstrating differential Cry-toxin-binding abilities of two different aminopeptidases from a susceptible insect.

Management of pemphigus vulgaris during acute phase

We present our experience with 21 patients of pemphigus vulgaris seen over a period of 10 years managed in service hospitals during acute phase of the disease. Age groups of patients ranged from 25-45 years. Eighteen (85.7%) were young adults, 30-40 years of age. Fifteen (71.4%) were men and 6 (28.6%) were women. All the cases were hospitalized in ICU, till the acute phase of the disease subsided. Complete hematological profile, urinalysis, serum biochemistry and repeated bacterial cultures from the skin were carried out in all patients at the time of admission and thereafter weekly. The treatment comprised of potassium permanganate lotion bath (1:10,000) and 1 framycetin gauze dressing of the denuded areas, maintenance of fluid and electrolyte balance. All suspected infections and septicemia were treated with appropriate antibiotics. The corticosteroids were usually administered as a single dose of prednisolone 1 mg/kg/day. Cyclophosphamide was given at an initial dose of 50 mg/day and the dose was escalated to 100 mg/day. Once the bulk of the lesions were healed, the dose of corticosteroids was gradually lowered by approximately 50% every two weeks and cyclophosphamide was continued till patients were symptom-free. Out of 21 patients receiving corticosteroids, cyclophosphamide and other supportive therapy, 20 (95%) had undergone clinical resolution of the disease. During follow up study 15 (71.4%) patients remained symptom-free and undergone clinical remission. Five patients (23.8%) had relapse, out of which 4 (19%) remained symptom free, after subsequent treatment. There was one death (4.7%) in our study.