A machine learning pipeline revealing heterogeneous responses to drug perturbations on vascular smooth muscle cell spheroid morphology and formation

Machine learning approaches have shown great promise in biology and medicine discovering hidden information to further understand complex biological and pathological processes. In this study, we developed a deep learning-based machine learning algorithm to meaningfully process image data and facilitate studies in vascular biology and pathology. Vascular injury and atherosclerosis are characterized by neointima formation caused by the aberrant accumulation and proliferation of vascular smooth muscle cells (VSMCs) within the vessel wall. Understanding how to control VSMC behaviors would promote the development of therapeutic targets to treat vascular diseases. However, the response to drug treatments among VSMCs with the same diseased vascular condition is often heterogeneous. Here, to identify the heterogeneous responses of drug treatments, we created an in vitro experimental model system using VSMC spheroids and developed a machine learning-based computational method called HETEROID (heterogeneous spheroid). First, we established a VSMC spheroid model that mimics neointima-like formation and the structure of arteries. Then, to identify the morphological subpopulations of drug-treated VSMC spheroids, we used a machine learning framework that combines deep learning-based spheroid segmentation and morphological clustering analysis. Our machine learning approach successfully showed that FAK, Rac, Rho, and Cdc42 inhibitors differentially affect spheroid morphology, suggesting that multiple drug responses of VSMC spheroid formation exist. Overall, our HETEROID pipeline enables detailed quantitative drug characterization of morphological changes in neointima formation, that occurs in vivo, by single-spheroid analysis.

Phosphoinositide Signaling and Mechanotransduction in Cardiovascular Biology and Disease

Phosphoinositides, which are membrane-bound phospholipids, are critical signaling molecules located at the interface between the extracellular matrix, cell membrane, and cytoskeleton. Phosphoinositides are essential regulators of many biological and cellular processes, including but not limited to cell migration, proliferation, survival, and differentiation, as well as cytoskeletal rearrangements and actin dynamics. Over the years, a multitude of studies have uniquely implicated phosphoinositide signaling as being crucial in cardiovascular biology and a dominant force in the development of cardiovascular disease and its progression. Independently, the cellular transduction of mechanical forces or mechanotransduction in cardiovascular cells is widely accepted to be critical to their homeostasis and can drive aberrant cellular phenotypes and resultant cardiovascular disease. Given the versatility and diversity of phosphoinositide signaling in the cardiovascular system and the dominant regulation of cardiovascular cell functions by mechanotransduction, the molecular mechanistic overlap and extent to which these two major signaling modalities converge in cardiovascular cells remain unclear. In this review, we discuss and synthesize recent findings that rightfully connect phosphoinositide signaling to cellular mechanotransduction in the context of cardiovascular biology and disease, and we specifically focus on phosphatidylinositol-4,5-phosphate, phosphatidylinositol-4-phosphate 5-kinase, phosphatidylinositol-3,4,5-phosphate, and phosphatidylinositol 3-kinase. Throughout the review, we discuss how specific phosphoinositide subspecies have been shown to mediate biomechanically sensitive cytoskeletal remodeling in cardiovascular cells. Additionally, we discuss the direct interaction of phosphoinositides with mechanically sensitive membrane-bound ion channels in response to mechanical stimuli. Furthermore, we explore the role of phosphoinositide subspecies in association with critical downstream effectors of mechanical signaling in cardiovascular biology and disease.

Zinc/copper ratio: a predictor of pancreatic function in chronic pancreatitis?

BACKGROUND

The role of trace elements in the maintenance of normal pancreatic function is unclear.

AIM

To estimate trace elements (zinc and copper) in chronic pancreatitis (CP) patients and study their relationship with exocrine and endocrine insufficiency. Methods: The study involved 101 CP patients and 113 healthy controls. Disease characteristics and imaging features were recorded. Erythrocyte zinc (Zn) and copper (Cu) were estimated by flame atomic absorption spectrophotometry. Fecal pancreatic elastase1 was estimated by polyclonal antibody ELISA method as a marker of pancreatic exocrine function.

RESULTS

The mean erythrocyte Zn level and Zn/Cu ratio were significantly lower whereas the copper level was significantly higher in CP patients than controls. The mean Zn level and Zn/Cu ratio was significantly lower in CP patients with diabetes and those with low elastase1 as compared to non-diabetics and those with normal elastase1 respectively. Erythrocyte Cu level was significantly higher in CP patients with diabetes and with low elastase1 than those without diabetes and with normal elastase1 levels respectively. There was a significant positive correlation between elastase1 and Zn/Cu ratio (r = 0.396, p < 0.001). Receiver operating characteristic curve (ROC) analysis was performed to predict the development of exocrine insufficiency and it indicated an area under curve (AUC) of 0.838 ± 0.047 (95% CI: 0.746-0.93). The optimal cutoff value was 9.03 (sensitivity 86.5%, specificity 73.5%). When the same was performed to predict the development of diabetes, the AUC was 0.710 ± 0.05 (95% CI: 0.607-0.812). The optimal cutoff value was 7.2 (sensitivity 69.1%, specificity 69.7%).

CONCLUSION

Low erythrocyte Zn/Cu ratio was found to be associated with exocrine and endocrine insufficiency in CP patients.

Comparison of efficacy of five types of long-lasting insecticidal nets against Anopheles fluviatilis, the primary malaria vector in east-central India

Five types of long-lasting insecticidal nets (LNs), namely, Olyset, Netprotect, PermaNet, DuraNet, and Interceptor, were tested after 20 washes for efficacy in terms of mortality, deterrence effect, blood-feeding inhibition, and induced exophily of the malaria vector Anopheles fluviatilis in experimental huts in Malkangiri district of Odisha State, India. Efficacy of the three synthetic pyrethroids (SPs) used in the LNs was also analyzed. Use of LNs reduced the entry of An. fluviatilis into the huts by 73.3-83.2%, and the five LNs were comparable in terms of deterrence. The exit rate of An. fluviatilis from the huts with untreated net was 56.3%, and relative to this, Olyset followed by DuraNet induced significantly a higher exophily. In contrast, the exit rate was significantly lower with Interceptor. Among the three SPs, permethrin induced significantly greater exophily relative to the untreated control, and as a result of this, permethrin-treated Olyset produced a lower mortality. Blood-feeding rate of An. fluviatilis was significantly lower with all the five LNs than the control. Similarly, all the three SPs significantly inhibited blood feeding compared with the control. Interceptor and DuraNet, both alphacypermethrin-treated LNs, caused relatively a higher mortality of An. fluviatilis than the other LNs. The five brands of LNs and three SPs tested in the current study were equally effective in terms of deterrence and blood-feeding inhibition; only exiting and killing effect differed among them. Permethrin-treated LNs induced greater exophily, while, overall, alphacypermethrin-treated LNs killed more An. fluviatilis that entered the huts. Advantage of deterrence, excito-repellent, and killing effects of LNs and appropriate selection of SP for net treatment are discussed in this paper.

Molecular diagnosis of urea cycle disorders: current global scenario

Urea cycle disorders are a group of inborn error of metabolism, characterized by hyperammonemia, metabolic alkalosis and clinical features of encephalopathy. These are among the commonest types of inborn errors of metabolism with a frequency of 1 in 8,000 to 1 in 30,000 in different population. This encompasses 5 major disorders, corresponding with deficiency of each step in the urea cycle, namely ornithine transcarbamoylase (OTC) deficiency, argininosuccinate lyase (ASL) deficiency, carbamoyl phosphate synthetase (CPS) deficiency, citrullinemia and argininemia. The most important clinical presentation is neurological abnormalities. The severity of UCD is correlated to extent of hyperammonemia. Early diagnosis and treatment are essential for successful patient outcome. Various modalities of treatment have been recommended; namely, treatment aimed at reducing ammonia level, including drugs like sodium benzoate and sodium phenyl butyrate, neuroprotective strategies, low protein diet, liver transplantation and hepatocyte transplantation. Molecular diagnosis is important to identify the pathogenesis of these disorders as well as it helps in prognosis. This review intends to summarize the important aspects of molecular diagnostic studies on urea cycle disorders.

Effects of micronutrient status on oxidative stress and exocrine pancreatic function in patients with chronic pancreatitis

Micronutrient deficiency and oxidative stress in relation to pancreatic exocrine insufficiency among chronic pancreatitis (CP) patients needs closer scrutiny. In this study, we examined the role of micronutrients (Zn and Cu) on oxidative stress related parameters and stool elastase-1 in tropical chronic pancreatitis (TCP) and alcoholic chronic pancreatitis (ACP) patients. We also compared oxidative stress parameters in CP patients with low and normal pancreatic stool elastase-1, estimation of which is the best available test for detecting pancreatic exocrine insufficiency. Ninety-one (56 male and 35 female) TCP cases, 84 ACP cases and 113 (60 male and 24 female) healthy controls were studied. Levels of reduced glutathione (GSH), ascorbic acid and zinc and activities of glutathione peroxidase (GPx), superoxide dismutase (SOD) reduced significantly, while thiobarbituric acid reactive substance (TBARS) and copper level increased significantly in erythrocytes of both ACP and TCP patients in comparison to healthy controls. However, we did not find differences in these parameters between diabetic and non-diabetic TCP patients or between diabetic and non-diabetic ACP patients. The study suggested an association between pancreatic exocrine insufficiency and oxidative parameters, while zinc deficiency was found to be correlated with SOD and pancreatic exocrine insufficiency in CP, irrespective of its etiology.

Systematic list of the species added to the mosquito museum at the Vector Control Research Centre, Pondicherry, India

Mosquito species housed in the mosquito museum at the Vector Control Research Centre, Pondicherry, India, were increased from 181 to 266 species belonging to 22 genera. The systematic list of the 85 species added to the collection is provided. The collection consists of a total of 31,874 adult specimens, of which 23,696 are individually mounted on minuten pins, while the rest are held in stock vials. It also includes 2,456 male genitalia and 470 female genitalia preparations, 3,523 larvae, 4,745 larval exuviae, and 3,057 pupal exuviae on microscope slides. Representative specimens of different species are available from 16 states and 3 union territories of India.

ErbB-2 expression and its association with other biological parameters of breast cancer among Indian women

OBJECTIVES

Overexpression of the epidermal growth factor receptor family genes, which include ErbB-1, 2, 3 and 4, has been implicated in a number of cancers. We have studied the extent of ErbB-2 overexpression among Indian women with sporadic breast cancer.

METHODS

Immunohistochemistry and genomic polymerase chain reaction (PCR) were used to study the ErbB2 overexpression. ErbB2 status was correlated with other clinico-pathological parameters, including patient survival.

RESULTS

ErbB-2 overexpression was detected in 43.2% (159/368) of the cases by immunohistochemistry. For a sub-set of patients (n = 55) for whom total DNA was available, ErbB-2 gene amplification was detected in 25.5% (14/55) of the cases by genomic PCR. While the ErbB2 overexpression was significantly higher in patients with lymphnode (chi2 = 12.06, P < or = 0.001), larger tumor size (chi2 = 8.22, P = 0.042) and ductal carcinoma (chi2 = 15.42, P < or = 0.001), it was lower in patients with disease-free survival (chi2 = 22.13, P < or = 0.001). Survival analysis on a sub-set of patients for whom survival data were available (n = 179) revealed that ErbB-2 status (chi2 =25.94, P < or = 0.001), lymphnode status (chi2 = 12.68, P < or = 0.001), distant metastasis (chi2 = 19.49, P < or = 0.001) and stage of the disease (chi2 = 28.04, P < or = 0.001) were markers of poor prognosis.

CONCLUSIONS

ErbB-2 overexpression was significantly greater compared with the Western literature, but comparable to other Indian studies. Significant correlation was found between ErbB-2 status and lymphnode status, tumor size and ductal carcinoma. ErbB-2 status, lymph node status, distant metastasis and stage of the disease were found to be prognostic indicators.

Role of plasma amino acids and gaba in alcoholic and non-alcoholic fatty liver disease-a pilot study

Alcohol appears to affect brain function, primarily by interfering with the action of gamma-aminobutyric acid (GABA) and other neurotransmitters. As alcohol is mainly metabolized in the liver, therefore we undertook this pilot study to monitor the patterns of changes in plasma amino-acid concentrations due to alcoholic and nonalcohol fatty liver disease and their relation with plasma GABA level. Plasma amino-acid concentrations were measured in 25 alcoholic liver disease (ALD) patients, 18 non-alcoholic fatty liver disease (NAFLD) patients, and 24 age and sex matched control subjects by HPLC. GABA concentration was elevated, while isoleucine and leucine levels reduced significantly in ALD patients compared to the control subjects. Methionine and phenylalanine levels elevated and valine content reduced significantly in ALD patients compared to other two groups, and GABA level was significantly correlated with methionine and phenylalanine. Plasma concentration of lysine was significantly reduced in both groups of liver disease patients compared to the control group, but was not correlated with GABA level. Glycine and tyrosine levels reduced significantly in NAFLD patients compared to other two groups and were significantly correlated with GABA. Interestingly, though amino acids such as alanine, histidine, proline and serine were not affected by liver diseases, but were significantly correlated with GABA level. This pilot study indicated that alcoholic liver disease presented a more deranged plasma amino acid pattern than nonalcoholic, and the amino acid imbalances. More studies are necessary to identify the role of any particular amino acid on brain function and on neurotransmitter(s).

Wash resistance of PermaNets in comparison to hand-treated nets

The wash resistance of factory produced PermaNets (with deltamethrin bonded to the netting with a resin) was studied by bioassays with Anopheles stephensi. Commercial detergent powders were used to wash the nets. For comparison, conventionally treated nets were washed and bio-assayed. Nets were washed under laboratory conditions using a Rotary shaker for 10min. Mosquito bioassays used standard WHO plastic cones with an exposure time of 3min. The PermaNet caused almost a 100% mortality of An. stephensi after up to 18 washes and >80% mortality up to 26 washes but after 30 washes mortality declined. The differences between the mortality of An. stephensi on treated nets washed with detergent or soap (uncoloured, non-perfumed) were not significant. When conventional nets dipped in deltamethrin (25mg/m(2)) or lambdacyhalothrin (10mg/m(2)) were washed under similar laboratory conditions, the wash resistance was markedly less than that of the PermaNet. In the case of deltamethrin, mosquito mortality remained >80% up to 12 washes and with lambdacyhalothrin mortality remained above 80% up to 11 washes. The relationship of 80% mortality from a 3min bioassay to effectiveness against free flying mosquitoes remains to be determined.

Mosquitoes of the mangrove forests of India: part 5--Chorao, Goa, and Vikhroli, Maharashtra

Mosquitoes of 14 species belonging to 9 subgenera and 9 genera were recorded in Chorao mangroves of Goa, and 12 species belonging to 9 subgenera and 7 genera in the mangroves of Vikhroli, Maharashtra, in India. Genera recorded were Aedes, Anopheles, Armigeres, Culex, Mansonia, Ochlerotatus, Orthopodomyia, Toxorhynchites, Uranotaenia, and Verrallina. Species common to both the mangroves were Ae. albopictus, Ae. novalbopictus, An. subpictus, Cx. sitiens, Oc. wardi, Ur. atra, and Ve. lugubris. Tree holes, crab holes, and swamp pools were the common larval habitats in Chorao, but tree holes were absent in Vikhroli. Adults of Ae. albopictus, Ae. novalbopictus, Ar. subalbatus, Cx. gelidus Cx. sitiens, Ma. indiana, Ur. atra, and Ve. lugubris were found landing on humans. Aedes novalbopictus, Oc. wardi, and Or. anopheloides are new records for the state of Goa.

Mosquitoes of the mangrove forests of India: part four--Coringa, Andhra Pradesh

Mosquitoes of 12 species belonging to 5 subgenera and 9 genera--Aedes, Anopheles, Culex, Diceromyia, Lorrainea, Rhinoskusea, Stegomyia, Toxorhynchites, and Verrallina--were recorded in the Coringa mangrove forest in Andhra Pradesh, India. Tree holes, crab holes, and swamp pools constituted the larval habitats with Lo. fumida being predominant in tree holes. Adults were found resting in tree holes, tree trunks, root bases, and in crab holes. Species involved in daytime feeding on humans were Ae. cancricomes, Cx. sitiens, Lo. fumida, Rh. wardi, and Ve. lugubris.

Mosquitoes of the mangrove forests of India: part six--Kundapur, Karnataka and Kannur, Kerala

Mosquitoes of 26 species belonging to 16 subgenera and 11 genera were recorded in the Kundapur mangroves of Karnataka, and 17 species belonging to 11 subgenera and 7 genera were recorded in the mangroves of Kannur, Kerala along the west coast of India. Genera recorded were Aedes, Anopheles, Armigeres, Culex, Heizmannia, Lutzia, Mansonia, Ochlerotatus, Tripteroides, Uranotaenia, and Verrallina. Species common to both mangrove forests were Ae. albopictus, Ae. vittatus, An. jamesi, Ar. subalbatus, Cx. gelidus, Cx. infantulus, Cx. pseudovishnui, Cx. sitiens, Cx. tritaeniorhynchus, Oc. wardi, Ur. atra, and Ve. luguhris. Tree holes and swamp pools were the common larval habitats, with more species occurring in tree holes in Kundapur than in Kannur. Adults of Ae. albopictus, Ae. vittatus, Ar. aureolineatus, Ar. subalbatus, Cx. bitaeniorhynchus, Cx. sitiens, Ma. uniformis, and Ve. lugubris bloodfed on humans.

A list of the mosquitoes housed in the mosquito museum at the Vector Control Research Centre, Pondicherry, India

The establishment of a mosquito museum at the Vector Control Research Centre, Pondicherry, India, is reported. The collection at present contains more than 14,800 adult mosquitoes, including 8,426 that are individually pinned. The collection also includes some 1,048 male and female genitalia preparations, and 815 larval and 444 pupal exuviae on microscope slides. Mosquitoes of 19 genera, 37 subgenera, and 181 species are housed in the museum, representing about 50% of the known species from India. A list of the species is provided.

Mosquitoes of the mangrove forests of India: part 2--Sundarbans, West Bengal

Mosquitoes of 19 species belonging to 9 subgenera and 6 genera, Aedes, Aedeomyia, Anopheles, Armigeres, Culex, and Mansonia, were recorded in Sundarbans mangrove forest in West Bengal, India. With 6 and 5 species, respectively, the 2 genera Culex and Anopheles were found to be more diverse while less than 3 species were recorded in the other 4 genera. Adults were mainly collected resting on walls in the guesthouse, tree holes in the forest, landing on humans in the guesthouse, and in the forest, and in light traps. Larvae were obtained from tree holes in the forest. The list of species recorded is not conclusive due to the restriction in access to most parts of the mangroves due to the presence of tigers. The occurrence of the urban species Cx. quinquefasciatus within the Sajnakhali sanctuary is indicative of the need to monitor environmental changes that result with the introduction of man-made facilities.

Mosquitoes of the mangrove forests of India: Part 1--Bhitarkanika, Orissa

In this first paper of a series on mosquitoes of the mangrove forests of India, details of mosquito species recorded in Bhitarkanika, Orissa, are presented. Forty-three species of mosquitoes belonging to 21 subgenera and 13 genera, Aedes, Anopheles, Armigeres, Coquillettidia, Culex, Ficalbia, Heizmannia, Lutzia, Mansonia, Ochlerotatus, Toxorhynchites, Uranotaenia, and Verrallina, were recorded. Predominant larval habitat was the tree holes, from which 15 species were taken. Adults were mostly found resting in crab holes, tree holes, and hoof prints in the forest area and on walls in the guesthouse area. About 14 species were caught in light traps, while 19 species landed on humans for feeding. Ae. franciscoi and Oc. feegradei are 2 new country records for India. Ae. cancricomes and Cx. perplexus, known only from Andaman Islands of India, are new records for mainland India.

Mosquito collections in the Jeypore Hill tracts of Orissa, India, with notes on three new country records, Culex (Lophoceraomyia) pilifemoralis, Culex (Lophoceraomyia) wilfredi, and Heizmannia (Heizmannia) chengi

The occurrence of Culex (Lophoceraomyia) pilifermoralis, Cx. (Lop.) wilfredi, and Heizmannia (Heizmannia) chengi is reported for the first time from India from mosquito collections made in the Jeypore hills, Orissa. In collections made during October 1998 from 10 locations, 74 species belonging to 12 genera and 20 subgenera were recorded. Larvae of 40 species were obtained from different larval habitats like bamboo, leaf axils, fallen logs, paddy fields, ponds, ground pools, rock pools, streams, and tree holes. Together with the 14 anopheline species from earlier records, this report brings to 88 the number of mosquito species in the Jeypore hills.

The larval habitat of Verrallina (Verrallina) lugubris and chaetotaxy of field-collected larvae

The larval habitat of Verrallina lugubris (Barraud) is defined based upon collection of 648 larvae from swamp pools from January to March 1998 in Pichavaram mangrove forest, and 125 larvae during September 1997 in Maravakadu mangrove forest in the eastern coast of South India. Salinity of the larval habitat ranged from 12,150 to 24,500 mg/liter in Pichavaram and from 11,600 to 13,000 mg/liter in Maravakadu. Associated mosquito species were Culex sitiens Wiedemann, Ochlerotatus portonovoensis (Tewari and Hiriyan), and Anopheles subpictus Grassi. The chaetotaxy of field-collected larvae of Ve. lugubris is presented.

Laboratory and field evaluation of Teknar HP-D, a biolarvicidal formulation of Bacillus thuringiensis ssp. israelensis, against mosquito vectors

Larvicidal efficacy of Teknar HP-D, an improved biolarvicidal formulation of Bacillus thuringiensis ssp. israelensis (Bti), against Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti was determined in the laboratory, and in field the efficacy of the formulation was tested against Cx. quinquefasciatus breeding in cesspits, unused wells and drains. The toxicity of the formulation to Gambusia affinis (larvivorous fish), Notonecta sp. and Diplonychus indicus (water bugs) was also evaluated in the laboratory. Teknar HP-D was field tested at three recommended dosages, 1, 1.5 and 2l/ha, selecting five habitats for each dosage. Another five habitats were kept untreated as controls. Ae. aegypti showed greatest susceptibility to the Bti toxin in the laboratory. In cesspits, all the three dosages caused >80% reduction of pupal recruitment up to day 6 post-treatment, indicating that a weekly application at the lowest would be necessary for sustained control. The residual activity of the formulation was longer in unused wells, causing >80% reduction of pupal recruitment for 17 days from the day of treatment. In controlling pupal recruitment the three dosages produced equal effect. Application of Teknar HP-D at 1 l/ha once in three weeks is therefore recommended to control Cx. quinquefasciatus in unused wells. However, in drains, >80% reduction of pupal recruitment was observed for only 3 days and hence, application of Teknar HP-D at 2 l/ha that caused significantly higher level of reduction twice in a week at 3-day interval is necessary. At dosages from 0.032 to 3.2 mg/l (ppm), Teknar HP-D was non-toxic to Gambusia fish. The two predatory water bugs, Notonecta sp. and Diplonychus indicus that fed on the surviving larvae of Cx. quinquefasciatus exposed to the sub-lethal doses (LC(50) and LC(80)) of Teknar HP-D were safe with out having any mortality.

Aedes fumidus and Aedes amesii in mangrove forests of India--two new country records

We report the first records of Aedes fumidus and Ae. amesii from India based on collections made in mangrove forests of Bhitarkanika in Orissa, Sunderbans, in West Bengal, and Andaman and Nicobar Islands. Collection details include date, location, material examined, larval habitat, and associated species.

A checklist of mosquitoes (Diptera: Culicidae) of Pondicherry, India with notes on new area records

A checklist of mosquito species for Pondicherry, India, is presented based on collections made from November 1995 to September 1997. Mosquitoes of 64 species were found belonging to 23 subgenera and 14 genera, Aedeomyia, Aedes, Anopheles, Armigeres, Coquillettidia, Culex, Ficalbia, Malaya, Mansonia, Mimomyia, Ochlerotatus, Toxorhynchites, Uranotaenia, and Verrallina. We report 25 new species for Pondicherry.

Analysis and implementation of software rejuvenation in cluster systems

Several recent studies have reported the phenomenon of "software aging", one in which the state of a software system degrades with time. This may eventually lead to performance degradation of the software or crash/hang failure or both. "Software rejuvenation" is a pro-active technique aimed to prevent unexpected or unplanned outages due to aging. The basic idea is to stop the running software, clean its internal state and restart it. In this paper, we discuss software rejuvenation as applied to cluster systems. This is both an innovative and an efficient way to improve cluster system availability and productivity. Using Stochastic Reward Nets (SRNs), we model and analyze cluster systems which employ software rejuvenation. For our proposed time-based rejuvenation policy, we determine the optimal rejuvenation interval based on system availability and cost. We also introduce a new rejuvenation policy based on prediction and show that it can dramatically increase system availability and reduce downtime cost. These models are very general and can capture a multitude of cluster system characteristics, failure behavior and performability measures, which we are just beginning to explore. We then briefly describe an implementation of a software rejuvenation system that performs periodic and predictive rejuvenation, and show some empirical data from systems that exhibit aging

Seasonal incidence of Aedes (Rhinoskusea) portonovoensis in a mangrove forest of South India

The seasonal incidence of Aedes (Rhinoskusea) portonovoensis in its type locality is reported. This is the Ist information on the bionomics of this species described from a mangrove forest in South India. Peak density of adults occurred in August. The larval habitat of the species is also defined.

Effect of improved nasal breathing on obstructive sleep apnea

OBJECTIVES

The goal was to compare the effect of an improved nasal airway on obstructive sleep apnea (OSA) by use of subjective and objective measures.

METHODS

A prospective study of 50 consecutive patients with nasal airway obstruction and OSA was carried out.

RESULTS

Subjectively, nasal breathing improved in 49 (98%) patients, whereas snoring decreased or disappeared in 17 (34%); the remaining 33 (66%) patients did not notice any significant change in their snoring. Daytime energy levels increased in 39 (78%) patients and remained unchanged or worsened in 11 (22%). In review of the polysomnographic data, the group overall did not have significant changes in respiratory disturbance index (RDI) or lowest oxygen saturation levels (LSaO(2)). Continuous positive airway pressure (CPAP) levels required to correct OSA decreased after nasal surgery (P < 0.01). Patients with mild OSA showed significant worsening in RDI (P < 0.05), whereas LSaO(2) levels were improved in the group with moderate OSA (P < 0.05). In patients with severe OSA neither the RDI levels nor the LSaO(2) changed, but CPAP levels required to alleviate the obstruction after surgery were reduced (P < 0.01).

CONCLUSIONS

Most patients report improvement in nasal and sleep symptoms after correction of nasal airway obstruction. However, nasal surgery alone does not consistently improve OSA when measured objectively. Depending on the severity of OSA, nasal airway reconstruction may contribute to a decrease in CPAP level and improvement in oxygen saturation. Correction of the obstructed nasal airway should certainly be included in the overall treatment plan for OSA.

Clinical predictors of obstructive sleep apnea

OBJECTIVE

To identify physical findings that can be standardized to predict the presence and the severity of obstructive sleep apnea (OSA).

STUDY DESIGN

One hundred seventy-two patients who answered questionnaires with responses that suggested they might have OSA were included in this prospective study.

METHODS

All patients underwent a physical examination and polysomnography. The physical examination included the measurement of four parameters used by anesthesiologists to identify patients likely to have difficult intubation to determine if these same parameters predict OSA. We recorded modified Mallampati grade (MMP), tonsil size, and body mass index (BMI) and measured thyroid-mental distance (TMD) and hyoid-mental distance (HMD) in the study population.

RESULTS

When the physical findings were correlated singly with the respiratory disturbance index (RDI), we found that MMP (P < .001), tonsil size grading (P = .008), and BMI (P = .003) were reliable predictors of OSA. A greater correlation with OSA emerged when an "OSA score" was formulated by factoring the MMP, tonsil grade, and BMI grade (RDI = 7.816 x MMP + 3.988 x Tonsil Size + 4.675 x BMI - 7.544). A high score was not only predictive of OSA but also correlated well with OSA severity. Neither HMD nor TMD correlated with the severity of RDI.

CONCLUSIONS

An OSA score may help identify those patients who should have a full sleep evaluation.

Monitoring visual outcome of cataract surgery in India

Two simple methods of assessing visual outcome following cataract surgery were evaluated in India. The first used data obtained from standardized patient records of cataract surgery. The second used data from population-based rapid epidemiological assessments. Analysis of 4168 hospital and eye camp records showed that, with the available standard correction, a good outcome (visual acuity > or = 6/18) was achieved in 37.8%, a borderline outcome (visual acuity 6/246-6/60) in 45.6% and a poor outcome (visual acuity 6/60) in 16.6% of instances. Of 2401 aphakic/pseudophakic eyes examined in a cross-sectional population-based study, outcome was good in 43.5% and poor in 26.4%. For 776 eyes examined in a similar study in a different state, outcome was good in 49.9% and poor in 23.9%. These assessments indicate that outcome with available correction was poor in 15-25% of eyes following cataract surgery. Visual outcome is likely to improve when better correction for aphakia can be provided. Further assessment of the causes of poor visual outcome is needed. The visual outcome following cataract surgery could be monitored on a regular basis by ophthalmologists, using either of the methods evaluated, an exercise which in itself is likely to improve the outcome of surgery. When the proportion of poor outcomes is high (> 10%) further investigation into the causes is warranted.

Changing trends in barriers to cataract surgery in India

Cataract is a major cause of blindness in Asia. Efforts in India to provide cataract surgical services have had limited success in reaching the cataract-blind population. Earlier studies identified the major barriers to cataract surgery as poverty, lack of transportation or felt need, or sex related; and the critical barriers in rural areas as lack of awareness, difficult access, and cost. Compared with these earlier data, the results of the present study in Karnataka State indicate a shift in the character of the barriers. They now appear to be more related to case selection and service provision. These shifts are analysed and alternative strategies to increase the uptake to cataract surgery are recommended.

Cataract blindness on the rise? Results of a door-to-door examination in Mohadi

A census survey in Mohadi block, Bhandara district of Maharashtra, indicated that the prevalence of blindness and cataract blindness has increased, compared with the 1986 survey. Around one third of the persons blind from cataract have been covered by surgical services. To increase coverage, more emphasis on information, education and communication is essential.

Rapid epidemiologic assessment of cataract blindness. The Aravind Rapid Epidemiologic Assessment Staff

A major constraint to obtaining reliable information about blindness and its causes in developing countries is the limited availability of ophthalmologists for diagnosis in population-based surveys. This study in rural south India assessed the feasibility of using non-ophthalmologists to make diagnoses in a population-based survey. Ten men in their early twenties with 12 years of schooling were recruited and trained as ophthalmic assistants through a six week course in basic ophthalmology. All people aged 40 and older in households in 24 villages were enumerated and invited to have an eye examination. At a central site, 1309 subjects were independently examined by an ophthalmologist and two different ophthalmic assistants. Ophthalmic assistant cataract diagnosis is both sensitive and specific relative to the ophthalmologist's diagnosis. Sensitivity and specificity estimates were used to adjust prevalence estimates obtained from ophthalmic assistant examinations conducted at the central site as well as at the doorstep of sample households. The findings indicate that epidemiologic assessment of cataract blindness can be completed using non-ophthalmologists to diagnose cataract.