RD-OCT net: hybrid learning system for automated diagnosis of macular diseases from OCT retinal images

Macular Edema is a leading cause of visual impairment and blindness in patients with ocular fundus diseases. Due to its non-invasive and high-resolution characteristics, optical coherence tomography (OCT) has been extensively utilized for the diagnosis of macular diseases. The manual detection of retinal diseases by clinicians is a laborious process, further complicated by the challenging identification of macular diseases. This difficulty arises from the significant pathological alterations occurring within the retinal layers, as well as the accumulation of fluid in the retina. Deep Learning neural networks are utilized for automatic detection of retinal diseases. This paper aims to propose a lightweight hybrid learning Retinal Disease OCT Net with a reduced number of trainable parameters and enable automatic classification of retinal diseases. A Hybrid Learning Retinal Disease OCT Net (RD-OCT) is utilized for the multiclass classification of major retinal diseases, namely neovascular age-related macular degeneration (nAMD), diabetic macular edema (DME), retinal vein occlusion (RVO), and normal retinal conditions. The diagnosis of retinal diseases is facilitated by the use of hybrid learning models and pre-trained deep learning models in the field of artificial intelligence. The Hybrid Learning RD-OCT Net provides better accuracy of 97.6% for nAMD, 98.08% for DME, 98% for RVO, and 97% for the Normal group. The respective area under the curve values were 0.99, 0.97, 1.0, and 0.99. The utilization of the RD-OCT model will be useful for ophthalmologists in the diagnosis of prevalent retinal diseases, due to the simplicity of the system and reduced number of trainable parameters.

Safety driven intelligent autonomous vehicle for smart cities using IoT

Purpose

Autonomous vehicles rely on IoT-based technologies to take numerous decisions in real-time situations. However, added information from the sensor readings will burden the system and cause the sensors to produce inaccurate readings. To overcome these issues, this paper aims to focus on communication between sensors and autonomous vehicles for better decision-making in real-time. The system has unique features to detect the upcoming and ongoing vehicles automatically without intervention of humans in the system. It also predicts the type of vehicle and intimates the driver.

Design/methodology/approach

The system is designed using the ATmega 328 P and ESP 8266 chip. Information from ultrasonic and infrared sensors are analyzed and updated in the cloud server. The user can access all these real-time data at any point of time. The stored information in cloud servers is used for integrating artificial intelligence into the system.

Findings

The real-time sensor information is used to predict the surrounding environment and the system responds to the user according to the situation.

Practical implications

The system is implemented on embedded platform with IoT technology. The sensor information is updated to the cloud using the Blynk application for the user in real time.

Originality/value

The system is proposed for smart cities with IoT technology where the user and the system are aware of the surrounding environment. The system is mainly concerned with the accuracy of sensors and the distance between the vehicles in real-time environment.

Prenatal Evaluation of Intracranial Hemorrhage on Fetal MRI: A Retrospective Review

BACKGROUND AND PURPOSE

The evaluation and characterization of germinal matrix hemorrhages have been predominantly described on postnatal head sonography in premature neonates. However, germinal matrix hemorrhages that are seen in premature neonates can be also seen in fetuses of the same postconceptual age and are now more frequently encountered in the era of fetal MR imaging. Our aim was to examine and describe the MR imaging findings of fetuses with intracranial hemorrhage.

MATERIALS AND METHODS

A retrospective review of diagnostic-quality fetal MRIs showing intracranial hemorrhage from January 2004 to May 2020 was performed. Images were reviewed by 2 radiologists, and imaging characteristics of fetal intracranial hemorrhages were documented. Corresponding postnatal imaging and clinical parameters were reviewed.

RESULTS

One hundred seventy-seven fetuses with a mean gestational age of 25.73 (SD, 5.01) weeks were included. Germinal matrix hemorrhage was identified in 60.5% (107/177) and nongerminal matrix hemorrhage in 39.5% (70/177) of patients. Significantly increased ventricular size correlated with higher germinal matrix hemorrhage grade (P < .001). Fetal growth restriction was present in 21.3% (20/94) of our population, and there was no significant correlation with germinal matrix grade or type of intracranial hemorrhage. An increased incidence of neonatal death with grade III germinal matrix hemorrhages (P = .069) compared with other grades was identified; 23.2% (16/69) of the neonates required ventriculoperitoneal shunts, with an increased incidence in the nongerminal matrix hemorrhage group (P = .026).

CONCLUSIONS

MR imaging has become a key tool in the diagnosis and characterization of intracranial hemorrhage in the fetus. Appropriate characterization is important for optimizing work-up, therapeutic approach, and prenatal counseling.

Evaluation of Posterior Fossa Biometric Measurements on Fetal MRI in the Evaluation of Dandy-Walker Continuum

BACKGROUND AND PURPOSE

Dandy-Walker malformation, vermian hypoplasia, and Blake pouch remnant represent a continuum of anomalies and are common reasons for referral for fetal MR imaging. This study aimed to determine biometric measurements that quantitatively delineate these 3 posterior fossa phenotypes.

MATERIALS AND METHODS

Our single-center institutional review board approved a retrospective analysis of all fetal MRIs for posterior fossa malformations, including Dandy-Walker malformation, vermian hypoplasia, and Blake pouch remnant. Measurements included the anterior-to-posterior pons, craniocaudal and anterior-to-posterior vermis, lateral ventricle size, and tegmentovermian and posterior fossa angles. Measurements were compared with normal biometry and also between each subgroup.

RESULTS

Thirty-three fetuses met the criteria and were included in the study. Seven were designated as having Dandy-Walker malformation; 16, vermian hypoplasia; and 10, Blake pouch remnant. No significant group interactions with adjusted mean gestational age for tegmentovermian and posterior fossa angles were observed. The tegmentovermian angle was significantly higher in Dandy-Walker malformation (109.5° [SD, 20.2°]) compared with vermian hypoplasia (52.13° [SD, 18.8°]) and Blake pouch remnant (32.1° [SD, 17.9°]), regardless of gestational age. Lateral ventricle sizes were significantly higher in Dandy-Walker malformation at a mean of ≥23.1 weeks' gestational age compared with vermian hypoplasia and Blake pouch remnant. The anterior-to-posterior and craniocaudal vermes were significantly smaller in Dandy-Walker malformation compared with vermian hypoplasia and Blake pouch remnant at mean of ≥23.1 weeks' gestational age.

CONCLUSIONS

Dandy-Walker malformation can be described in relation to vermian hypoplasia and Blake pouch remnant by an increased tegmentovermian angle; however, other potential qualifying biometric measurements are more helpful at ≥23.1 weeks' gestational age. Because they fall along the same spectrum of abnormalities, the difficulty in distinguishing these entities from one another makes precise morphologic and biometric descriptions important.

The impact of viral hepatitis-related hepatocellular carcinoma to post-transplant outcomes

Hepatocellular carcinoma (HCC) is the most common complication of HCV infection leading to liver transplantation. We evaluated the impact of aetiology of liver disease on patient and graft survival following liver transplantation for HCC. From the Scientific Registry of Transplant Recipients (2002-2011), all adults who underwent liver transplantation for HCC were retrospectively included. Aetiology of liver disease was grouped into HCV, HBV, HCV-HBV co-infection and nonviral liver disease. Of 8,733 liver transplant recipients with HCC, 5507 had HCV, 631 had HBV, 163 were co-infected, and 2432 had nonviral causes of liver disease. In follow-up (48 ± 32 months), 8.2% had graft failure and 29.5% died. The mean rates of graft failure were 9.5%, 4.7%, 6.1% and 6.4% in HCV, HBV, HCV-HBV co-infection and nonviral liver disease, respectively (P < 0.0001). Post-transplant mortality rate in patients with HBV was 20.2%, HCV 31.0%, HCV-HBV 28.5% and nonviral 28.5% (P < 0.0001). This difference was significant starting one year post-transplant and became even more prominent later in follow-up. Five-year post-transplant survival was 64.7% in HCV, 77.7% in HBV, 71.0% in HCV-HBV and 69.1% in nonviral HCC (P < 0.0001). A diagnosis of HCV in patients with HCC was also independently associated with an increased risk of both graft failure (adjusted hazard ratio = 1.84 (1.46-2.33), P < 0.0001) and mortality (1.35 (1.21-1.50), P < 0.0001) in multivariate analysis. Patients with HCV-related HCC are at higher risk of adverse post-transplant outcomes. These patients should be considered for preemptive interferon-free antiviral therapy prior to or immediately following liver transplantation.

Inpatient resource utilization, disease severity, mortality and insurance coverage for patients hospitalized for hepatitis C virus in the United States

Although the incidence of new hepatitis C virus (HCV) infection has fallen, HCV-related complications are on the rise. Our aim was to assess and describe the 2005-2009 national inpatient mortality and resource utilization trends for patients with HCV. Data from the National Inpatient Sample (NIS) and the National Hospital Discharge Survey (NHDS) between 2005 and 2009 were analyzed. Included were all adult hospital discharges with HCV-related ICD-9 codes. Incremental hospital charge, in-hospital mortality and length of stay (LOS) were estimated using n = 1000 bootstrap replicates clustered by unique hospital identifier. A total of 123 939 (0.38%) discharges were related to HCV (primary or secondary diagnosis). In-hospital mortality increased from 1.7% (2005) to 2.6% (2009) (P < 0.001). Inflation-adjusted charges increased 2% annually from 2005 ($16 455 ± $570) to 2009 ($17 532 ± $1007, P = 0.029). This increase occurred despite the average LOS (5 days) and hospital costs ($6500) remaining stable while at the same time, hospital-to-hospital transfer admissions and disposition to home health care increased. HCV-related hepatocellular carcinoma predicted longer hospital stay and death; older age predicted death; and receiving more procedures predicted higher hospital costs. The percentage of patients with private insurance significantly decreased (4.7%), while government-sponsored insurance and uninsured increased by 2.5% and 2.1%, respectively (P < 0.05). Uninsured patients had a 49%-72% greater chance of dying during hospitalization than those with government-sponsored insurance. HCV-related inpatient mortality and resource utilization have increased. HCC was the largest predictor for mortality and resource utilization. These data are consistent with the rising clinical and societal burden of chronic hepatitis C in the United States.

Cytotoxicity, genotoxicity and oxidative stress of malachite green on the kidney and gill cell lines of freshwater air breathing fish Channa striata

The cytotoxicity, genotoxicity and oxidative stress of malachite green (MG) was investigated using the fish Channa striata kidney (CSK) and Channa striata gill (CSG) cell lines. Five concentrations ranging from 0.001 to 10 μg mL(-1) were tested in three independent experiments. Cytotoxicity was assessed by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, Rhodamine 123 and Alamar Blue. The mitochondrial changes and apoptosis of MG-exposed cells were observed by Rhodamine 123 and acridine orange/ethidium bromide (AO/EB) staining, respectively. In vitro potential DNA damaging effect of MG was tested using comet assay. Mitochondrial damage, apoptosis and DNA fragmentation increased in a concentration-dependent manner. Additionally, DNA electrophoretic mobility experiments were carried out to study the binding effect of MG to double-stranded DNA (dsDNA) of cells. DNA shift mobility experiments showed that MG is capable of strongly binding to linear dsDNA causing its degradation. Biochemical parameters such as lipid peroxidation (MDA), catalase (CAT) activity and reduced glutathione (GSH) levels were evaluated after exposure to MG. In CSK and CSG cell lines exposed to MG for 48 h, a significant increase in lipid peroxidation, which might be associated with decreased levels of reduced glutathione and catalase activity in these cell lines (p < 0.001), was observed.

Detection and neutralization of cobra venom using rabbit antiserum in experimental envenomated mice

A sandwich enzyme-linked immunosorbent assay (ELISA) was developed to detect the venom of Indian cobra ( Naja naja naja) in various tissues (brain, heart, lungs, liver, spleen, blood, kidneys, and tissue at the site of injection) of mice after cobra venom injected at different time intervals (0, 2, 4, 6, 8, and 12 h intervals up to 24 h). Whole venom antiserum or individual venom protein antiserum (14, 29, 65, 72, and 99 kDa) could recognize N. n. naja venom by Western blotting and ELISA, and antibody titer was also assayed by ELISA. Antiserum raised against cobra venom in rabbit significantly neutralized the toxicity of venom-injected mice at different time intervals after treatment. The assay could detect N. n. naja venom levels up to 2.5 ng/ml of tissue homogenate, and the venom was detected up to 24 h after venom injection. Venom was detected in brain, heart, lungs, liver, spleen, kidneys, tissue at the bite area, and blood. As observed in mice, tissue at the site of bite area showed the highest concentration of venom and the brain showed the least. Moderate amounts of venoms were found in liver, spleen, kidneys, heart, and lungs. Development of a simple, rapid, and species-specific diagnostic kit based on this ELISA technique useful to clinicians is discussed.

The impact of chronic hepatitis C on resource utilisation and in-patient mortality for Medicare beneficiaries between 2005 and 2010

BACKGROUND

As baby boomers age, chronic hepatitis C (CHC) will become increasingly important in Medicare eligible group.

AIM

To evaluate trends in Medicare resource utilisation for CHC.

METHODS

We analysed the Medicare in-patient and out-patient data from 2005 to 2010. For each patient, all claims with CHC as a principal diagnosis were added up and yearly CHC-related spending was calculated.

RESULTS

A total of 48,880 out-patient claims for 21,655 CHC patients and 4884 hospital admission claims for 3092 patients were included. The number of in-patient (1.5-1.6/year) or out-patient (2.2-2.3/year) visits per patient did not change over time, nor did the demographic characteristics of the CHC population. The majority of this population was eligible for Medicare based on disability and the average number of diagnoses per in-patient claim (from 8.11 in 2005 to 8.60 in 2010) and per out-patient claim (from 2.18 in 2005 to 2.71 in 2010) increased (both P < 0.0001). The average total yearly spending per patient increased in the out-patient setting from $488 in 2005 to $584 in 2010 (P = 0.0132) and did not change in the in-patient setting (from $22,245 in 2005 to $23,383 in 2010, P = 0.14). In the multivariate analysis, the number of diagnoses and conditions per claim and the number of in-patient or out-patient procedures per year were the important independent predictors of increased resource utilisation.

CONCLUSIONS

Most Medicare beneficiaries with chronic hepatitis C who sought in-patient or out-patient care in 2005-2010 had received Medicare for disability. Although the total resource utilisation did not change, the proportion of patient's responsibility increased.

Neutralization of cobra venom by cocktail antiserum against venom proteins of cobra (Naja naja naja)

Naja naja venom was characterized by its immunochemical properties and electrophoretic pattern which revealed eight protein bands (14 kDa, 24 kDa, 29 kDa, 45 kDa, 48 kDa, 65 kDa, 72 kDa and 99 kDa) by SDS-PAGE in reducing condition after staining with Coomassie Brilliant Blue. The results showed that Naja venom presented high lethal activity. Whole venom antiserum or individual venom protein antiserum (14 kDa, 29 kDa, 65 kDa, 72 kDa and 99 kDa) of venom could recognize N. naja venom by Western blotting and ELISA, and N. naja venom presented antibody titer when assayed by ELISA. The neutralization tests showed that the polyvalent antiserum neutralized lethal activities by both in vivo and in vitro studies using mice and Vero cells. The antiserum could neutralize the lethal activities in in-vivo and antivenom administered after injection of cobra venom through intraperitoneal route in mice. The cocktail antiserum also could neutralize the cytotoxic activities in Vero cell line by MTT and Neutral red assays. The results of the present study suggest that cocktail antiserum neutralizes the lethal activities in both in vitro and in vivo models using the antiserum against cobra venom and its individual venom proteins serum produced in rabbits.

Synthesis and characterization of chitosan tripolyphosphate nanoparticles and its encapsulation efficiency containing Russell's viper snake venom

Chitosan Tripolyphosphate (CS/TPP) nanoparticle is a biodegradable and nontoxic polysaccharide, used as a carrier for drug delivery. The morphology and particle-size measurements of the nanoparticles were studied by field emission scanning electron microscopy and Fourier Transform Infrared Spectroscopy (FTIR). This study aims to evaluate the impact of Russell's viper venom encapsulation on various factors and loading capacity, in addition to explore the physicochemical structure of nanoparticles. FTIR confirmed that tripolyphosphoric groups of TPP linked with ammonium groups of CS in the nanoparticles. Our results showed that CS can react with TPP to form stable cationic nanoparticles. The results also showed that encapsulation efficiency of venom at different concentrations of 20, 40, 60, 500, and 1000 µg/mL were achieved for CS/TPP nanoparticles at different concentrations of 1.5, 2, and 3 mg/mL. The cytotoxicity of CS/TPP nanoparticles was evaluated by MTT (-3 (4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide, a tetrazole) assay.

Antivenom activity of triterpenoid (C34H68O2) from Leucas aspera Linn. against Naja naja naja venom induced toxicity: antioxidant and histological study in mice

The isolated and identified triterpenoid, 1-hydroxytetratriacontane-4-one (C34H68O2), obtained from the methanolic leaf extract of Leucas aspera Linn. was explored for the first time for antisnake venom activity. The plant (L. aspera Linn.) extract significantly antagonized the spectacled cobra (Naja naja naja) venom induced lethal activity in a mouse model. It was compared with commercial antiserum obtained from King Institute of Preventive Medicine (Chennai, Tamil Nadu, India). N. naja naja venom induced a significant decrease in antioxidant superoxide dismutase, glutathione (GSH) peroxidase, catalase, reduced GSH and glutathione-S-transferase activities and increased lipid peroxidase (LPO) activity in different organs such as heart, liver, kidney and lungs. The histological changes following the antivenom treatment were also evaluated in all these organs. There were significant alterations in the histology. Triterpenoid from methanol extract of L. aspera Linn. at a dose level of 75 mg per mouse significantly attenuated (neutralized) the venom-induced antioxidant status and also the LPO activity in different organs.

Moderate, excessive or heavy alcohol consumption: each is significantly associated with increased mortality in patients with chronic hepatitis C

BACKGROUND

The impact of moderate alcohol consumption on long-term outcomes of chronic hepatitis C (CH-C) infected patients remains controversial.

AIM

To assess the impact of moderate alcohol consumption on long-term outcomes of CH-C patients using population-based data.

METHODS

Data were obtained from the Third National Health and Nutrition Examination Survey (NHANES III)-mortality linked files. Alcohol consumption was estimated as grams/day. Multivariate Cox proportional hazards model was utilized to assess the effects of CH-C and alcohol consumption on mortality (all causes, cardiovascular disease, and liver disease).

RESULTS

A total of 8985 participants were included as the study cohort. Of these, 218 had CH-C. The follow-up time was 162.95 months for CH-C and 178.27 months for controls. CH-C patients had increased risk for both overall mortality and liver-related mortality. CH-C patients with excessive alcohol consumption had even higher risks for overall mortality and liver-related mortality. The risk of overall mortality associated with CH-C increased with moderate alcohol consumption of 1-19 g/day and heavy alcohol consumption ≥30 g/day.

CONCLUSION

Although chronic hepatitis C is associated with increased risks for overall and liver-related mortality, these risks are even higher for patients consuming moderate and excessive amounts of alcohol.

A 2012 clinical update for internists in adult nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in the Western world. Associated with the metabolic syndrome, NAFLD is associated with adverse cardiovascular outcomes. A subset of NAFLD patients with histologic nonalcoholic steatohepatitis (NASH) can have increased liver related mortality. Because of the prevalence and complications of this chronic liver disease, it is important that internists understand important aspects about diagnosis and management. In this article, we aim to provide an update to clinicians related to issues surrounding prognosis, monitoring, and treatment.

Experimental exposure of Artemia to hepatopancreatic parvo-like virus and subsequent transmission to post-larvae of Penaeus monodon

The different life stages of Artemia franciscana were experimentally exposed to Hepatopancreatic parvo-like virus (HPV), in order to evaluate the possibility of Artemia acting as reservoir or carrier for HPV. All the five developmental stages of Artemia were challenged with HPV both by immersion and oral infection routes. The viral infectivity to Artemia was studied by PCR but not much difference in mortality between control and challenge groups were observed. To confirm the vector status of Artemia for HPV, the HPV exposed Artemia were fed to postlarval forms of Penaeus monodon. Post-larvae of P. monodon were fed with HPV exposed Artemia and could get infected upon feeding on them. Mortality was observed in the post-larvae, which were fed with HPV exposed Artemia, and whereas no mortality was observed in post-larvae fed with Artemia not exposed to HPV and these post-larvae were PCR negative for HPV, as well. Results of this experiment suggest that Artemia might be a possible horizontal transmission pathway for HPV. Further research however is required with histology, immunohistochemistry and transmission electron microcopy to determine whether the Artemia are actually infected with this virus or whether they are simply mechanical carriers. This will enable us to understand better whether Artemia is a carrier of this virus and if so the mechanism involved.

Oral delivery of DNA construct using chitosan nanoparticles to protect the shrimp from white spot syndrome virus (WSSV)

The protective efficacy of oral delivery of a DNA construct containing the VP28 gene of WSSV encapsulated in chitosan nanoparticles was investigated in black tiger shrimp (Penaeus monodon). The results showed that significant survival was obtained in WSSV-challenged shrimp at 7, 15 and 30 days post-treatment (relative survival, 85%, 65% and 50%, respectively) whereas 100% mortality was observed in the control shrimp fed with feed containing chitosan/pcDNA 3.1 or chitosan/PBS complex. The ability of the chitosan to form a complex with the pVP28 and to stabilize it from endonuclease degradation was studied by agarose gel electrophoresis. Cytotoxicity of chitosan-encapsulated pVP28 was also evaluated by the MTT assay, which showed 90% viability of SISK cells incubated with the pVP28/chitosan complexes. Transcription analysis of the chitosan-encapsulated pVP28 gene in different tissues of DNA-treated shrimp and SISK cell line was confirmed by an RT-PCR reaction. The present study also measured the changes in the level of important immunological parameters such as prophenoloxidase, superoxide dismutase and superoxide anion in hemolymph of chitosan-encapsulated VP28 DNA-treated and controls shrimp. The study also correlated the changes in the level of immunological parameters with the survival percentage and protective efficacy of oral route of DNA construct against WSSV in shrimp.

Studies on the immunomodulatory effect of extract of Cyanodon dactylon in shrimp, Penaeus monodon, and its efficacy to protect the shrimp from white spot syndrome virus (WSSV)

The present study investigates the protection of shrimp Penaeus monodon against white spot syndrome virus (WSSV) using antiviral plant extract derived from Cyanodon dactylon and the modulation of the shrimp non-specific immunity. To determine the antiviral activity, the shrimp were treated by both in vitro (intramuscular injection) and in vivo (orally with feed) methods at the concentration of 2mg per animal and 2% of the plant extract incorporated with commercially available artificial pellet feed, respectively. The antiviral activity of C. dactylon plant extract was confirmed by PCR, bioassay and Western blot analysis. In the present study, anti-WSSV activity of C. dactylon plant extract by in vivo and in vitro methods showed strong antiviral activity and the immunological parameters such as proPO, O(2)(-), NO, THC and clotting time were all significantly (P<0.05) higher in the WSSV-infected shrimp treated with plant extract when compared to control groups. These results strongly indicate that in vivo and in vitro administration of C. dactylon plant extract enhances immunity of the shrimp. Based on the present data and the advantages of plant extract available at low price, we believe that oral administration of C. dactylon plant extract along with the pellet feed is a potential prophylactic agent against WSSV infection of shrimp.

Clearance of white spot syndrome virus (WSSV) and immunological changes in experimentally WSSV-injected Macrobrachium rosenbergii

A time course experimental challenge of WSSV was carried out to examine the clearance of WSSV in Macrobrachium rosenbergii and the consequent immunological changes. The experimental animals were injected with WSSV and the samples of gills, pleopods, head soft tissue and hemolymph were collected at different intervals of 1, 3, 5, 10, 25, 50, 75 and 100 days post infection (p.i.). WSSV infection and clearing were confirmed by single step PCR, nested PCR and bioassay. At 3 days p.i., M. rosenbergii became lethargic and stopped feeding in contrast to the control prawns that behaved and fed normally. However, the WSSV-injected prawns suffered no mortality during the experimental period and recovered without any further gross signs of disease or any mortality over a period of 100 days p.i. The single step PCR analysis showed positive at 1, 3 and 5 days p.i. in gills, head soft tissue, pleopods and hemolymph, and all the organs showed negative at 10 days p.i. onwards. The nested PCR results showed that all organs were positive for WSSV from 3 days p.i. and extended up to 25 days p.i. At 50 days p.i, head soft tissue sample alone showed WSSV-positive while all other organs were negative by nested PCR. All the organs at 75 and 100 days p.i. showed nested PCR negative for WSSV as observed in the control prawn. The hemolymph collected from experimentally infected M. rosenbergii at 1, 3 and 5 days p.i. caused 100% mortality at 40 h p.i., 55 h p.i. and 72 h p.i, respectively in Penaeus monodon whereas hemolymph collected at 10, 25, 50, 75 and 100 days p.i. failed to cause mortality in shrimp. The moribund shrimp showed WSSV-positive and surviving shrimp showed negative by PCR. Immunological parameters such as proPO, O(2)(-) and clotting time in WSSV-injected M. rosenbergii were found to be significantly higher than those of the control groups, whereas THC and superoxide dismutase were significantly lower when compared to control groups.

Oral administration of bacterially expressed VP28dsRNA to protect Penaeus monodon from white spot syndrome virus

We explored the possibility of protecting Penaeus monodon against white spot syndrome virus (WSSV) infection via interference RNA technology by oral administration of bacterially expressed WSSV VP28dsRNA. Shrimp were given dsRNA orally via two methods. In the first method, pellet feed was coated with inactivated bacteria containing overexpressed dsRNA of the WSSV VP28 gene, and in the second method, pellet feed was coated with VP28dsRNA-chitosan complex nanoparticles. The treated shrimp were orally challenged with WSSV by feeding WSSV-infected tissue. The experiment was conducted for 30 days. The dsRNA-treated shrimp challenged with WSSV showed higher survival compared to control shrimp. Sixty-eight percent survival was observed in shrimp fed with feed coated with inactivated bacteria containing dsRNA of the WSSV VP28 gene whereas 37% survival was observed in shrimp fed with VP28dsRNA-chitosan complex nanoparticle-coated feed. The WSSV caused 100% mortality in shrimp fed with pellet feed coated with inactivated bacteria with empty LITMUS38i vector. At the end of the experiment, the tissue samples prepared from randomly selected shrimp that survived were analyzed via reverse transcriptase-polymerase chain reaction and Western blot analysis for WSSV. The samples were negative for WSSV. Based on the present data and the advantages of dsRNA, we believe that oral administration of crude extract of bacterially expressed VP28dsRNA is a potential therapeutic agent against WSSV infection of shrimp.

Natural aquatic insect carriers of Macrobrachium rosenbergii nodavirus (MrNV) and extra small virus (XSV)

Five different species of aquatic insects were collected from nursery ponds containing the freshwater prawn Macrobrachium rosenbergii infected with Macrobrachium rosenbergii nodavirus (MrNV) and extra small virus (XSV). The insects were screened as potential natural carriers of MrNV and XSV. RT-PCR (reverse transcription polymerase chain reaction) analysis gave positive results for MrNV and XSV in Belostoma sp., Aesohna sp., Cybister sp. and Notonecta sp., and negative results for Nepa sp. An Aedes albopictus mosquito cell line (C6/36) was used for infectivity assays, with viral inoculum prepared from the aquatic insects, since C6/36 cells have recently been shown to be susceptible to infection with MrNV and XSV. The C6/36 cells were harvested 4 d post-challenge for examination by electron microscopy. This revealed aggregation of viral particles throughout the cytoplasm for cells challenged with inocula from all the insect species except Nepa sp. Our results indicate that several aquatic insect species may present a risk for MrNV and XSV transmission to M. rosenbergii.

Diagnostic utility of serologic markers for genital chlamydial infection in STD patients in Chennai, India

OBJECTIVES

To evaluate the diagnostic utility of serological markers for C. trachomatis in different clinical groups of STD patients.

METHODS

Blood and genital swab specimens were collected from symptomatic STD patients (n=143) attending the STD out patient clinic at the Institute of STDs, Government General hospital, Chennai who enrolled for the study. Serological determination for IgM, IgA and IgG antibodies to C. trachomatis was done using commercial kits. PCR analysis was performed on genital swab samples by using plasmid and major outer membrane protein (MOMP) based primers and patients who were positive by both PCR assays were considered as proven cases of C. trachomatis infection. The serological marker positivity was analysed with PCR positivity.

RESULTS

Serologic positivity by IgM, IgA and IgG was 22.4%, 28.7% and 58.7% respectively. The PCR analysis showed 44 (30.8%) cases with confirmed C. trachomatis infection. Seropositivity for IgM (34.1% (15/44) vs. 17.2% (17/99); P<0.05) as well as for IgA (40.9% (18/44) vs. 23.2% (23/99); P<0.05) significantly correlated to PCR positivity, while significant correlation was not seen with IgG positivity. The overall seropositivity (IgM/IgA/IgG) in the study population was 68.5%.

CONCLUSIONS

The observations of the present study indicate a high exposure rate to chlamydial infection in STD clinic patients in India. The study also suggests the usefulness of serology instead of PCR to trace chlamydial etiology, especially in deep-seated upper genital tract diseases and to facilitate better clinical management as there was good correlation between serology and PCR positivity.

Genital chlamydial infection in STD patients: its relation to HIV infection

In the present report, we have analysed C.trachomatis infection and HIV positivity among patients (n-143) who attended the STD clinic at the Institute of STDs, Government General Hospital, Chennai. HIV positivity rate was significantly high among those with chlamydial infection than in those without chlamydial infection (29.5% (13/44) vs. 11.1% (11/99); p<0.05). The results of the present study suggest the association between C.trachomatis and HIV infections and reinforce the need for routine screening for C.trachomatis as a necessary intervention to reduce the burden of chlamydial diseases and to reduce the risk of HIV and its spread in India.

Need for specific & routine strategy for the diagnosis of genital chlamydial infection among patients with sexually transmitted diseases in India

BACKGROUND & OBJECTIVES

With increasing burden of human immunodeficiency virus (HIV) infection acquired immunodeficiency syndrome (AIDS) in India, documentation on the epidemiology of genital chlamydial infections in high-risk patients with sexually transmitted diseases (STD) is of significant public health value. Specific diagnosis is essential to prevent the morbidity due to the chlamydial infection and to reduce the risk of acquiring HIV infection. The present study was undertaken to analyse the usefulness of culture and antigen detection by direct fluorescent antibody (DFA) test for assessing the rate of Chlamydia trachomatis infection in symptomatic patients and feasibility of these tests for routine adoption in Indian setting.

METHODS

Clinically diagnosed patients of both sex (n=143) attending the Institute of Sexually Transmitted Diseases, Government General Hospital, Chennai who consented for the study, were enrolled. Clinical and demographic details were recorded on a stratified proforma. Genital swab specimens collected from them were subjected for culture using McCoy cell line and for antigen detection by DFA testing.

RESULTS

C. trachomatis was isolated in 27 of the total 143 patients (18.9%). Culture positivity was seen in 11 of the 63 (17.5%) males and in 16 of 80 (20%) females. DFA detected C. trachomatis specific antigen in 35 patients (24.5%); 15 (23.8%) males and 20 (25%) females. The rate of C. trachomatis diagnosis increased to 25.2 per cent by adopting both the methods as against 18.9 per cent by culture only and 24.5 per cent by DFA only. No association of C. trachomatis infection with any predictable genitourinary symptom (s), was seen.

INTERPRETATION & CONCLUSION

The findings show a high infection rate for C. trachomatis in symptomatic patients with STD. Clinical symptoms alone can be unreliable in specifically predicting infections with C. trachomatis. Specific diagnostic tests need to be recommended for routine inclusion in the STD diagnosis to facilitate risk reduction of HIV infection in STD patients.

Clinical manifestations of HIV infected children

OBJECTIVE

Heterosexual contact is the predominant mode of transmission among adults in India with an increasing number of women of childbearing age becoming infected with HIV. Consequently, children in India increasingly getting infected, primarily from vertical transmission. A retrospective review of the profile of HIV infected children attending an HIV clinic in South India is reported.

METHODS

All HIV-infected children under 15 years of age at the time of first presentation and managed at this center between June 1996 and June 2000 are included in this report. Socio-demographic characteristics and clinical manifestation were collected in a precoded proforme. A complete physical examination and baseline laboratory investigations were performed at entry into the clinic and at subsequent follow-up.

RESULTS

Fifty-eight HIV-infected children were included: thirty-nine (67.2%) were male with mean age 4 years. Perinatal transmission was the predominant mode of HIV acquisition (67%). Common clinical manifestations in these children at presentation included oral candidiasis (43%), pulmonary tuberculosis (35%), recurrent respiratory infections (26%), bacterial skin infection (21%), papulo-pruritic dermatitis (19%), hepatosplenomegaly and lymphadenopathy (14%) each and chronic diarrhea (7%).

CONCLUSION

An understanding of the epidemiology of pediatric HIV infection may reveal opportunities to reduce and perhaps eliminate perinatal transmission. Knowledge of clinical manifestations in this setting will help physicians meet the management challenges presented by HIV infected children.

Perinatal gonadectomy affects corticocortical connections in motor but not visual cortex in adult male rats

Sexual dimorphisms and/or hormone modifiability have been documented for numerous structural endpoints in the cerebral cortex, including cortical thickness and dendrite morphology. The present study asked whether gonadal steroids might also sculpt cortical circuit organization. Accordingly, neonatal gonadectomy, with and without testosterone propionate replacement, was followed by fine-grained microcircuit tract tracing analyses of the organization of corticocortical circuits of identified layers of primary motor and primary visual cortices in the same animals in adulthood. Comparative analyses revealed neither qualitative nor quantitative differences in visual cortical circuit organization between gonadectomized and control animals. In primary motor cortex, circuit organization was also qualitatively similar in the two animal groups. However, quantitative analyses uncovered small, but highly consistent, decreases in the horizontal breadth of motor cortical connections in the hormonally deprived group. These decreases were attenuated in gonadectomized rats that were supplemented with testosterone propionate. Furthermore, quantitative analysis of cytoarchitecture revealed that visual and motor circuits in both gonadectomized groups resided in cortical areas with dimensions that were statistically invariant from corresponding measures obtained in control animals. These findings suggest that cortical circuits should be among anatomical substrates considered in relation to observed sex differences in and/or hormone modifiability of the maturation of identified cortical functions. These findings may also have relevance for cortical dysmaturation and dysfunction in disorders such as schizophrenia and dyslexia, diseases in which sex differences in incidence suggest some role for gonadal steroids.

Cellular and subcellular sites for noradrenergic action in the monkey dorsolateral prefrontal cortex as revealed by the immunocytochemical localization of noradrenergic receptors and axons

A series of electron microscopic immunocytochemical studies was performed to analyze subcellular sites for noradrenergic modulation in monkey prefrontal cortex. One out of 12 noradrenergic varicosities, identified by dopamine beta-hydroxylase immunocytochemistry within single ultrathin sections, forms morphologically identifiable junctions with small dendrites and spines. Accordingly, alpha2-adrenergic receptors, almost all of which are of the A-subtype, that occur in spines are localized discretely over postsynaptic membranes. alpha2-Adrenergic receptors are also found at sites along axons, dendritic shafts and astrocytic processes lacking morphologically identifiable synaptic junctions, suggesting that these receptors are activated by volume transmission. In particular, axonal alpha2-adrenergic receptors occur mostly at pre-terminal regions, suggesting that axo-axonic interactions may mediate reduction of neurotransmitter release at sites other than axo-spinous junctions by closing voltage-dependent calcium channels. These results indicate that noradrenergic modulation of prefrontal cortex involves synaptic interactions at spines of pyramidal neurons and nonsynaptic volume transmission to glia, dendritic shafts and axons.

Cellular and subcellular distribution of alpha 2A-adrenergic receptors in the visual cortex of neonatal and adult rats

Activation of alpha 2-adrenergic receptors (alpha 2AR) in the cerebral cortex has been shown to modulate visually guided delayed response tasks as well as anxiety and depression. We used an antiserum directed specifically against the A subtype of alpha 2AR (alpha 2AAR) to determine the cell types and subcellular sites for noradrenergic reception mediated by this receptor in the adult and the developing rat visual cortices. Light microscopic examination of adult tissue revealed numerous labeled perikarya in layers II-VI, many of which appeared distinctly pyramidal. A few perikarya in layer I also were immunoreactive. In all layers, alpha 2AAR immunoreactivity (alpha 2AAR-ir) was present within proximal dendrites and fine processes. In neonatal tissue, there was an intense, distinct band of immunoreactivity spanning the layer composed of tightly packed immature cell bodies, i.e., the cortical plate. The band dissipated as this tier differentiated postnatally into the supragranular layers. Electron microscopy showed that the supragranular layers, which contain the highest density of noradrenergic fibers, also contain the highest areal density of labeled postsynaptic junctions beyond 2 weeks of age. Throughout the ages, the majority of immunoreactivity occurred at sites which, in single ultrathin sections, appeared to be nonjunctional sites of axons, dendrites, and in glial processes. Our observations indicate that (1) both pyramidal and nonpyramidal neurons are receptive to norepinephrine via alpha 2AAR, (2) alpha 2AAR synthesis is robust prior to synaptogenesis, and (3) alpha 2AAR operates both pre- and postsynaptically.

Cellular and subcellular localization of NMDA-R1 subunit immunoreactivity in the visual cortex of adult and neonatal rats

NMDA receptor activation can alter synaptic strength, cause cell death, and may modulate the release of glutamate and other neurotransmitters. Using a specific and selective antiserum directed against the R1 subunit of the NMDA receptor, we examined (1) whether NMDA receptors in the adult rat visual cortex are exclusively postsynaptic or also presynaptic and (2) whether NMDA-R1 subunits are incorporated into the plasma membrane prior to, contemporaneously, or following the formation of synapses during postnatal development. By light microscopy, NMDA-R1 immunoreactivity in the adult visual cortex is easily detectable within perikarya and proximal dendrites in laminae 2-6. Many of them have the morphological features of pyramidal neurons. In addition, fine punctate labeling is evident throughout the neuropil. Electron microscopy reveals these puncta to reside at postsynaptic densities of axospinous junctions and at fine astrocytic processes and axon terminals. In the deeper laminae, the majority of labeled profiles are astrocytic. Visual cortices of animals in their first postnatal week show concentrated immunoreactivity in a few nonpyramidal neurons within laminae that have just differentiated from the cortical plate. Electron microscopy reveals diffuse labeling along the plasma membrane of dendritic shafts lacking morphologically identifiable synaptic junctions or appositions to axons. Immunoreactivity is detectable in dendritic processes by postnatal day (PND) 2, in axonal processes by PND 4, and in astrocytic profiles by PND 14. Immunoreactivity also is detectable along the postsynaptic membrane of presumably transient axosomatic junctions. At all ages, the prevalence of NMDA-R1-immunoreactive profiles is lamina 1 > 4/5 > 6/6B. These results provide the cellular basis for NMDA receptors' participation in (1) postsynaptic membrane excitability, (2) regulation of transmitter release, (3) and, in the deeper laminae, astrocyte responses. During development, NMDA-R1 subunits are associated with the plasma membrane prior to axons' arrival while clustering of receptors to junctions may be promoted by axonal contact. Finally, spatial segregation of axonal growth cones may be mediated by NMDA-R1 subunits on these axonal processes.

Perikaryal and synaptic localization of alpha 2A-adrenergic receptor-like immunoreactivity

Through molecular cloning, the existence of three distinct subtypes of alpha 2-adrenergic receptors (alpha 2AR)--A, B and C--has been established and are referred to as alpha 2A AR, alpha 2B AR and alpha 2CAR. Due to limitations in pharmacological tools, it has been difficult to ascribe the role of each subtype to the central functions of alpha 2AR. In situ hybridization studies have provided valuable information regarding their distribution within brain. However, little is known about their subcellular distribution, and in particular, their pre- versus postsynaptic localization or their relation to noradrenergic neurons in the CNS. We used an antiserum that selectively recognizes the A-subtype of alpha 2AR to determine: (1) the regional distribution of the receptor within brains of rat and monkey; (2) the subcellular distribution of the receptor in locus coeruleus (LC) of rats and prefrontal cortex of monkeys; and (3) the ultrastructural relation of the receptor to noradrenergic processes in LC. Light microscopic immunocytochemistry revealed prominent immunoreactivity in LC, the brainstem regions modulating the baroreflex, the granule cell layer of the cerebellar cortex, the paraventricular and supraoptic nuclei of the hypothalamus (PVN, SON), the basal ganglia, all thalamic nuclei, the hippocampal formation and throughout cerebral cortical areas. Comparison of results obtained from rat and monkey brains revealed no apparent interspecies-differences in the regional distribution of immunoreactivity. Immunoreactivity occurred as small puncta, less than 1 micron in diameter, that cluster over neuronal perikarya. Besides these puncta, cell bodies, proximal dendrites and fine varicose processes--most likely to be axonal--of the PVN and SON and the hippocampal granule cells also exhibited homogeneously intense distribution of immunoreactivity. Subcellularly, alpha 2AAR-ir in LC and prefrontal cortex were associated with synaptic and non-synaptic plasma membrane of dendrites and perikarya as well as perikaryal membranous organelles. In addition, cortical tissue, but not LC, exhibited prominent immunoreactivity within spine heads. Rat brainstem tissue immunolabeled dually for alpha 2AAR and dopamine beta-hydroxylase (D beta H, the noradrenaline-synthesizing enzyme) revealed that alpha 2AAR-li occurs in catecholaminergic terminals but is also prevalent within non-catecholaminergic terminals. Terminals exhibiting alpha 2AAR-li formed symmetric and asymmetric types of synapses onto dendrites with and without D beta H-immunoreactivity. These results indicate that: (1) the A-subtype of alpha 2AR is distributed widely within brain; (2) alpha 2AAR-li reflects the presence of newly synthesized alph 2AAR in perikarya as well as those receptors along the plasma membrane of perikarya, dendritic trunks and spines; and (3) alpha 2AAR in LC may operate as heteroreceptors on non-catecholaminergic terminals as well as autoreceptors on noradrenergic terminals.

Spatial-frequency- and orientation-selectivity of simple and complex channels in region segregation

Models incorporating spatial-frequency- and orientation-selective channels explain many texture-segregation results, particularly when known nonlinearities are included. One such nonlinearity is complex channels. A complex channel consists of two stages of linear filtering separated by a rectification-type nonlinearity. Here we investigate the spatial-frequency- and orientation-selectivity of simple (linear) channels and of the complex channels' first stage. Observers rated the degree of segregation between two "textures" both composed of elements which were Gabor patches. When the textures differed in type of element (e.g. one composed of vertical and the other of horizontal Gabor patches), the segregation results yield bandwidth estimates for simple channels of approx. 0.5-1.0 octave on the spatial-frequency dimension and 5-20 deg of rotation on the orientation dimension. When the textures differ in the arrangement of elements (e.g. striped vs checkerboard arrangements, both of horizontal and vertical patches), the segregation results yield bandwidth estimates for the first stage of complex channels. These estimates, while differing substantially from one observer to another, were always substantially wider than those for simple channels (by at least a factor of two) but narrower than bandwidths of LGN cells (particularly on the orientation dimension where LGN cells show little selectivity at all).

Non-linear processes in perceived region segregation: orientation selectivity of complex channels

Models incorporating linear spatial-frequency- and orientation-selective channels explain many aspects of visual texture segregation. The inability of such models to fully explain texture segregation results, indicates that non-linear processes are also involved. One non-linearity that has been suggested is complex channels consisting of two stages of linear filtering separated by a rectification-type non-linearity (much like cortical complex cells). Here we further demonstrate the usefulness of complex channels in explaining texture segregation results and investigate the orientation-selectivity of the first stage of such complex channels. Our results suggest that the first stage is much more selective for orientation than are lateral geniculate nucleus cells, but that the first-stage orientation bandwidth is rather wide with some interaction occurring between perpendicular orientations.