Improved Diagnostic Sensitivity of Bowel Disease of Prematurity on Contrast-Enhanced Ultrasound

Bowel diseases of prematurity, including necrotizing enterocolitis, are dreaded ailments of neonates. Early diagnosis is difficult, with clinical and radiographic findings often inconclusive. We present a novel use of contrast-enhanced ultrasound in detection of pediatric bowel disease. Early identification of compromised blood flow or an at-risk bowel can be quantitatively detected and monitored. This ability has implications for guidance of emerging therapies, allowing targeting of inflammation. These findings represent an advancement in detection of bowel disease in neonates.     

Postpemphigus acanthomata: a sign of clinical activity?

Background Pemphigus is a group of vesiculobullous disorders in which the blisters usually heal with hyper- or hypopigmentation. The appearance of acanthomata at sites of previous blisters has been noted in some cases. Methods All cases of pemphigus admitted to the Madras Medical College hospitals during a 2-year period from March 1993 to March 1995 were taken into the study and screened for the presence of acanthomata. Results Fifty-two cases of pemphigus were identified, 47 of pemphigus vulgaris and five of pemphigus foliaceus; and of these 13 developed acanthomata when the blisters healed. Ten of these cases were of pemphigus vulgaris and three were of pemphigus foliaceus; biopsy of these lesions showed hyperkeratosis, acanthosis, papillomatosis, and intraepidermal clefting. Immunofluorescence carried out in two of these acanthomata also showed intercellular fluorescence. Conclusions The occurrence of acanthomata in healed lesions of pemphigus is not uncommon; because histopathologic and immunofluorescence evidence of disease activity is present, cases of this sort require careful follow-up.     

Pheochromocytoma and pregnancy: a case report and review of anesthetic management

PURPOSE: To describe a patient diagnosed with pheochromocytoma in the third trimester of pregnancy and discuss the perioperative and anesthetic management. CLINICAL FEATURES: A 32-yr-old previously healthy woman (gravida 4, para 2) presented to our tertiary care obstetrical hospital at 34 weeks five days gestation with a history of labile blood pressure and severe hypertension. A week prior to admission she began having episodes of severe headache, dizziness, sweating and nausea. On a routine obstetric visit she was noted to be severely hypertensive with a blood pressure of 200/120 mmHg. Biochemical investigations confirmed the diagnosis of pheochromocytoma and magnetic resonance imaging demonstrated a 3 cm x 3 cm right adrenal mass. The patient was invasively monitored in the intensive care unit and treated with alpha- followed by beta-blockade with phenoxybenzamine and metoprolol. A multidisciplinary conference was organized involving endocrinology, anesthesiology, general surgery and obstetrics to determine the most appropriate management of the patient. An uncomplicated laparoscopic adrenalectomy was performed following a period of recovery after an uneventful elective Cesarean delivery. CONCLUSIONS: The primary goals in the management of pheochromocytoma in pregnancy are early diagnosis, avoidance of a hypertensive crisis during delivery and definitive surgical treatment. Timing of surgical resection will depend on the gestational age at which diagnosis is made. Cesarean section is the preferred mode of delivery when the tumour is still present. This case illustrates that with antenatal diagnosis, advanced methods of tumour localization, adequate preoperative adrenergic blockade and team planning, pheochromocytoma in pregnancy can be treated successfully.     

High HIV prevalence and risk behaviors in men who have sex with men in Chennai, India

OBJECTIVE: To estimate HIV and sexually transmitted disease (STD) prevalence and behavioral risk characteristics of men who have sex with men (MSM) in Chennai, India. METHODS: A cross-sectional population-based random sample survey was conducted in 2001. Randomly selected residents of 30 slums in Chennai were interviewed for behavioral risk factors through face-to-face interviews. Sera and urine were examined for syphilis, HIV-1, gonorrhea, and chlamydia. Logistic regression analyses were used to assess associations between MSM status and HIV infection and to identify risk characteristics of MSM. RESULTS: Of 774 men, 46 reported (5.9%) sex with other men. MSM were more likely to be seropositive for HIV (odds ratio [OR] = 8.57; 95% confidence interval [CI]: 1.83, 40.23) and were more likely to have a history of STD (OR = 2.66; 95% CI: 1.18, 6.02) than non-MSM. Men who used illicit drugs in past 3 months (adjusted odds ratio [AOR] = 4.01; 95% CI: 1.92, 8.41), ever exchanged money for sex (AOR = 3.93; 95% CI: 1.97, 7.84), or were ever tested for HIV (AOR = 3.72; 95% CI: 1.34, 10.34) were significantly more likely to report sex with men. CONCLUSIONS: MSM in Chennai slums are at high risk for HIV. HIV prevention strategies aimed at changing unsafe drug and sexual practices should target the general population of men, with specific attention to areas with high rates of MSM.     

Crosslinked polyimide foams derived from poly(imidepropylene oxide) copolymers

A new route for the synthesis of high glass transition temperature, thermally stable polymer foams has been developed, using compositionally asymmetric microphase-separated block copolymers where the minor component (poly(propylene oxide)) is thermally labile and the major component (polyimide) is thermally stable. The minor component decomposes to low molecular weight species upon heating, and the decomposition products diffuse out of the film, leaving behind pores embedded in a matrix of the thermally stable component. In this study, the polyimide block was crosslinked with ethynyl functionalities to obtain a stable porous structure. The decomposition of the propylene oxide in the block copolymer was studied by thermogravimetric, dynamic mechanical and thermomechanical analyses. Mild conditions were required to avoid rapid depolymerization of the propylene oxide and plasticization of the polyimide matrix. The foams showed pore sizes with diameters up to a micrometer in size as well as the expected reduction in the mass density.     

Inhibition of interleukin-2 production by adherent cell factors from lepromatous leprosy patients.

Twenty-four hour supernatants (MoF) were obtained from monocyte rich 2 h adherent cells of 19 leprosy patients and four healthy contacts. MoF from borderline and lepromatous patients produced 52-61% inhibition of human interleukin-2 (IL-2) production by a PHA conditioned T cell line (Jurkat). Non-adherent cell supernatants and MoF from tuberculoid and healthy individuals had little effect on IL-2 production. The suppression effected by MoF was in the first 12 h of initiation of PHA stimulated Jurkat cell cultures. Suppressive MoF did not interfere with (1) IL-2 release, (2) IL-2 utilization by Con A-induced T cell blasts or (3) constitutive proliferation of Jurkat cells. Such MoF were released spontaneously from adherent cells of bacilliferous leprosy patients but required in vitro antigen triggering in long term treated lepromatous patients. It is possible that the unresponsiveness associated with lepromatous leprosy is related to the inhibition of IL-2 production by suppressive factors, thereby, preventing the further expansion of antigen reactive T cells.     

Roles of specific amino acids in the N terminus of Pseudomonas aeruginosa flagellin and of flagellin glycosylation in the innate immune response

The Toll-like receptor 5 (TLR5) binding site has been predicted to be in the N terminus of the flagellin molecule. In order to better define the interaction between the N-terminal amino acids of Pseudomonas aeruginosa flagellin and TLR5, site-specific mutations were generated between residues 88 and 97 of P. aeruginosa PAK flagellin as well as outside of this region. The mutant flagellins were expressed in Escherichia coli BL21(plysS), purified by affinity chromatography, and passed through a polymyxin B column to remove contaminating lipopolysaccharide (LPS). Their ability to stimulate interleukin-8 (IL-8) release from A549 cells was examined. The cloned mutated genes were used to complement a PAK fliC mutant in order to test for effects on motility and on IL-8 release by purified flagellar preparations. All the mutations, single or double, in the predicted TLR5 binding region reduced IL-8 signaling to less than 95% of the wild-type flagellin levels, but the single mutation outside the binding region had no effect. Changes made at two amino acid sites resulted in loss/reduction of motility; however, changes made at single sites, i.e., Q83A, L88A, R90A, M91A, L94A, and Q97A, had no effect on motility. The mutated genes encoding two of the motile but poorly signaling flagellins had no compensatory mutations to allow motility. Thus, while it is speculated that pathogen-associated molecular patterns (PAMPs) have evolved in locations that are essential to maintain function, it appears that there is tolerance for at least single amino acid changes in the PAMP of P. aeruginosa flagellin. The purpose of flagellin glycosylation in P. aeruginosa is unknown. In order to examine its role, if any, in signaling an inflammatory response, we used whole flagella from the motile chromosomal mutant strains PAKrfbC and PAO1rfbC, which are defective in flagellin glycosylation. IL-8 release from A549 cells stimulated with nonglycosylated flagellar preparations (having less then 1 picogram of LPS/mug) was significantly reduced compared to their respective wild-type flagellar preparations, indicating a role of flagellar glycosylation in the proinflammatory action of Pseudomonas flagellin. The basis of the latter activity is unknown, since the glycosylation sites are found in the D3 domain of flagellins and the TLR5 binding site is located in the D1 domain. Thus, P. aeruginosa flagellin has evolved additional flagellar signaling mechanisms over that described for Salmonella flagellin.     

M1 protein triggers a phosphoinositide cascade for group A Streptococcus invasion of epithelial cells

Invasion of nonphagocytic cells by bacteria provides a favorable niche for persistence and evasion of host defenses and antibiotics. M protein is a major virulence factor because it promotes high-frequency invasion of epithelial cells by group A Streptococcus (GAS) and also renders the bacterium resistant to phagocytosis. In this study, we investigated the role of M1 protein from serotype M1 strain 90-226 in regulating mammalian signal transduction and cytoskeletal rearrangement for bacterial entry. LY294002 and wortmannin, which are inhibitors of phosphatidylinositol 3-kinase (PI 3-K) blocked invasion of epithelial cells by GAS by 75 and 80%, respectively, but failed to inhibit invasion by Salmonella enterica serovar Typhimurium. Also, epithelial cells transiently transfected with dominant negative p85 and p110 genes, the regulatory and catalytic subunits of PI 3-K, respectively, were less able to be invaded by GAS. To separate the influence of other streptococcal virulence factors from M protein, Lactococcus lactis was engineered to express M1 protein on its surface. L. lactis(pLM1) invaded epithelial cells efficiently in vitro, and PI 3-K inhibitors blocked 90% of this invasion. Purified soluble M1 protein stimulated the formation of stress fibers and actin tuffs on epithelial cells. LY294002 and wortmannin inhibited these cellular changes. A phosphoinositide analogue also inhibited the invasion of epithelial cells by GAS. Therefore, M1 protein, either directly or via bound fibronectin, initiates signals that depend on the lipid kinase PI 3-K pathway, which paves the way for cytoskeletal rearrangement that internalize the bacterium.     

Molecular and genetic characterizations of five pathogenic and two non-pathogenic monoclonal antiphospholipid antibodies

Antiphospholipid syndrome (APS) is an autoimmune disease that is characterized by thrombosis, recurrent fetal loss and thrombocytopenia. Antiphospholipid antibodies, detected by enzyme-linked immunoabsorbent assays (aCL) and/or in vitro blood clotting assays (LAC) are strongly associated with APS. Both the molecular structures used by pathogenic antiphospholipid antibodies and the genetic mechanisms leading to their production are unknown. We describe here the variable region genes of seven IgG antiphospholipid antibodies derived from two APS patients. Of these, five are pathogenic as defined in a mouse model of thrombosis and two are not. Analyses of the expressed variable region genes show no preferential V gene usage. However, similar to anti-DNA antibodies, pathogenic antiphospholipid antibodies contain an increased number of arginine residues in the third complimentarity-determining region (CDR3) of their H chains. The increased accumulation of arginine residues in the V(H) CDR3 may act to enhance antigen binding, promote disease and point to the importance of the H chain in the pathogenic potential of certain antiphospholipid antibodies.