Size-Class and Sex Dependent Variations of Burrow Architecture of Fiddler Crab, <Emphasis Type="Italic">Uca rosea</Emphasis> (Tweedie, 1937) in Sundarbans

Excavation of burrows by fiddler crabs are a crucial component of functional dynamics in mangrove ecosystem. Eleven burrow characters of rosy fiddler crab Uca rosea (Tweedie) were compared between two biotopes in Indian Sundarbans, throughout the year. Substratum qualities and mean shore level were estimated monthly. Mean density and sex ratio was calculated. Multivariate analysis of variance revealed significant differences (P < 0.05) in burrow morphology in different size classes of the species and in different seasons. Nine out of eleven characteristics differed between male and female fiddler crabs including burrow diameter (mm), burrow volume (cm³), total burrow length (mm) and depth (mm), chamber diameter (mm), burrow neck height (mm) etc., being larger in males than in females. These can be attributed to the presence of large chelipeds in males. Although, the two sites were different regarding the substratum composition, percent organic carbon and organic matter content, soil pH and shore level, the burrow morphology of rosy fiddler crab followed a fixed pattern that did not change even in different habitat.     

Magnetic resonance imaging and characterization of spontaneous lesions in a transgenic mouse model of tuberous sclerosis as a model for endothelial cell-based transgene delivery

Tuberous sclerosis (TSC) is an autosomal dominant genetic disorder characterized by abnormalities in cellular migration, proliferation, and differentiation in many tissues. Benign hamartomas develop in multiple organs, believed to be caused by somatic mutation in addition to germ line mutation to cause loss of both alleles of either the TSC1 or TSC2 tumor suppressor gene, with resultant dysregulated growth due to loss of hamartin or tuberin function, respectively. This study focuses on detecting spontaneous lesions in a knockout mouse model of TSC2 by magnetic resonance imaging (MRI) and exploring the efficiency of introducing gene products into lesions, using transduced endothelial cells as gene vehicles. MRI was shown to be effective in detecting spontaneous lesions in multiple tissues as a means of assessing the prevalence of tumors. Tsc(2+/) heterozygous mice were screened at 12-24 months of age. MRI detected 100% of the renal lesions (cystadenomas, renal cell carcinomas) and 75% of the hepatic lesions (hemangiosarcomas), later identified by histology. Cell-mediated gene delivery was evaluated by immunohistochemical analysis of renal, hepatic, and lung lesions after intravenous delivery of MS1 mouse endothelial cells, transduced to express an enhanced form of green fluorescent protein (EGFP). Preliminary immunohistochemical analysis, using a polyclonal antibody to EGFP and a horseradish peroxidase-diaminobenzidine detection system, revealed these cells throughout liver, kidney, and lung sections from injected animals, organs that are frequently affected in TSC2 patients, as well as within the lesions themselves.     

Intra-aortic balloon pump (IABP) rescue therapy for refractory cardiogenic shock due to scorpion sting envenomation

Background: Cardiomyopathy, cardiogenic shock or acute pulmonary oedema are well recognised complications of scorpion sting envenomation occurring in about 1–3% of patients. Current treatment recommendations include afterload reduction using prazosin and improving cardiac contractility with inotropes like dobutamine. We report the use of intra-aortic balloon pump (IABP) as rescue therapy in a patient with refractory cardiogenic shock due to Mesobuthus tamulus (Indian red scorpion) envenomation. Case: A 32-year-old woman was referred 24 h after a scorpion sting. At presentation she was ventilated and in circulatory shock (systolic blood pressure?<50?mmHg). After admission, the patient had four cardiac arrests (three episodes of pulseless ventricular tachycardia/ventricular fibrillation and one episode of asystole) over the next few hours. Following resuscitation, despite a combination of dobutamine, noradrenaline, and adrenaline, blood pressure did not improve significantly. In view of persistent tachycardia (heart rate 160/min), catecholamine storm was suspected and prazosin was added. However, shock was refractory. Hence, IABP was considered as rescue therapy. Following initiation of IABP, there was improvement in cardiac function (improved ejection fraction) which translated to weaning of inotropes over 48 h and improved organ function (renal, respiratory) in the next 2–3 d. However, following extubation, on Day 8, she was noted to have features of hypoxic brain injury. This improved gradually. At discharge (Day 30) she was independent for activities of daily living and was able to mobilise without support. Conclusion: IABP could be generally considered as a rescue therapy in refractory cardiogenic shock in envenomations.     

Characterization of human immunodeficiency virus (HIV1C) variants in peripheral blood mononuclear cells and spermatozoa

The presence of distinct viral variants in different cells and secretions of the same person influences the transmission of HIV as well as the response to the host defense and to therapy. Sperm-associated virus is also a risk factor for sexual transmission of HIV. Characterization of the C2-V3 region of HIV1C env gene by the Heteroduplex Mobility Assay (HMA) and sequencing demonstrated the presence of distinct variants in the peripheral blood mononuclear cells (PBMCs) and the sperm of the same individual (n = 6). The translated amino acid sequences of HIV variants in the PBMCs of all the study participants (n = 12) and spermatozoa of the six participants characterized showed the presence of distinct variants with different numbers of N-linked glycosylation (NLG) sites. Infectivity of PBMCs of these persons by co-culture with PBMCs from healthy individuals as detected by the p24 levels in the culture supernatant did not show a correlation with the blood plasma viral load. Interestingly, the infectivity of the sperm samples from four of the five individuals showed positive correlation with the viral load in seminal plasma. The study suggests the presence of distinct viral variants in the sperm and PBMCs of the same person with differential infectivity, and the NLG sites may be associated with the affinity of HIV to receptor/co-receptor usages as well as affinity toward neutralizing antibodies which may influence the risk of sperm associated virus in sexual transmission of HIV and transmit the virus further to distal cells.     

The impact of angiotensin-converting enzyme inhibitors and angiotensin-receptor blockers in patients with Clostridium difficile infection

There is increasing frequency and severity of disease due to Clostridium difficile infection (CDI). In addition, failure of initial antibiotic therapy is increasing. Angiotensin-converting enzyme inhibitors (ACEI) and angiotensin-receptor blockers (ARBs) may have local and systemic anti-inflammatory properties to reduce severity of disease in CDI. We performed a retrospective study of 306 patients with CDI over 23 months at a single center in Detroit, Michigan. Patient outcomes (death, death due to CDAD and relapse rates) were compared based on the use of ACEI or ARB during an episode of CDI. A total of 116 (37.9%) patients received an ACEI/ARB and 190 (62.1%) did not. The groups were similar except ACEI/ARB patients were older (71.9 vs. 64.3, P<0.0005) and had a higher frequency of congestive heart failure (50.9% vs. 30.2%, P<0.0005) and chronic obstructive pulmonary diseases (44.8% vs. 30.2%, P<0.010). ACEI/ARB patients had lower overall mortality rates (9.5% vs. 23.3%, P<0.002) as well as mortality due to CDI (2.6% vs. 8.6%, P<0.036). The rate of CDI relapse was not significantly different between the groups (5.2% in ACEI/ARB vs. 10.0%, P=0.135). Logistic regression analysis demonstrated that ACEI/ARB use was associated with lower overall mortality rate (OR 0.26; 95% CI, 0.12-0.55) and mortality due to CDI (OR 0.29; 95% CI, 0.08-1.02). Our findings suggest that ACEI/ARBs may have a role as an adjuvant therapy to antibiotics in patients with CDI. Prospective studies are needed to confirm these results.     

PDGF-mediated protection of SH-SY5Y cells against Tat toxin involves regulation of extracellular glutamate and intracellular calcium

The human immunodeficiency virus (HIV-1) protein Tat has been implicated in mediating neuronal apoptosis, one of the hallmark features of HIV-associated dementia (HAD). Mitigation of the toxic effects of Tat could thus be a potential mechanism for reducing HIV toxicity in the brain. In this study we demonstrated that Tat-induced neurotoxicity was abolished by NMDA antagonist-MK801, suggesting the role of glutamate in this process. Furthermore, we also found that pretreatment of SH-SY5Y cells with PDGF exerted protection against Tat toxicity by decreasing extracellular glutamate levels. We also demonstrated that extracellular calcium chelator EGTA was able to abolish PDGF-mediated neuroprotection, thereby underscoring the role of calcium signaling in PDGF-mediated neuroprotection. We also showed that Erk signaling pathway was critical for PDGF-mediated protection of cells. Additionally, blocking calcium entry with EGTA resulted in suppression of PDGF-induced Erk activation. These findings thus underscore the role of PDGF-mediated calcium signaling and Erk phosphorylation in the protection of cells against HIV Tat toxicity.     

MRI appearance of perianal carcinoma in Crohn's disease

Detection of carcinoma in perianal Crohn's disease can be difficult. The purpose of this study was to describe the MRI appearance of anorectal cancer in patients with perianal Crohn's disease. A total of six patients with anorectal carcinoma (four mucinous adenocarcinoma, two squamous) in Crohn's disease were retrospectively reviewed. Axial T2 and dynamic postcontrast fat-suppressed T1-weighted gradient echo sequences were performed, and findings were compared with 18 noncancer patients with perianal fistulae in Crohn's disease. MRI characteristics of carcinoma were irregular inner wall contours and delayed mild enhancement of internal tissue. The combined features of an irregular internal wall and delayed enhancing tissue were seen exclusively in cancer patients. The four cases of mucinous adenocarcinoma all displayed a pattern of lobulated fluid-filled cavities with delayed internal tissue enhancement. This pattern was not seen in any of the control cases. The presence of a double-layered enhancement pattern was seen in both cases of squamous carcinoma and in only one of four cases of mucinous adenocarcinoma and one of 18 noncancer cases. The pattern of contrast enhancement is valuable in the MRI diagnosis of carcinoma in perianal Crohn's disease.