Risk factors for Trypanosoma cruzi infection among children in central Brazil: a case-control study in vector control settings

This population-based case-control study was conducted in northern Goias State, central Brazil, in rural settings under vector control surveillance. One hundred forty-nine children seropositive for Trypanosoma cruzi antibodies, selected in a cross-sectional survey carried out in village schools, were compared with 298 seronegative classmate controls matched for age, sex, and place of residence. Information on potential environmental, familiar, and social economic risk factors for T. cruzi infection was collected during household visits, and interviews with parents and entomologic inspections of domestic and peridomestic environments were conducted. The presence of triatomines in dwellings or evidence of triatomine colonization was found to be statistically associated with seropositivity in children. The presence of exuviae and a report of triatomines indoors or outdoors by householders in the past were strong predictors of an infected child. Children from seropositive mothers had a 3.9-fold increase in the risk of having anti-T. cruzi antibodies after adjusting for the confounding variables, including triatomine capture, mother's age, and family size in multivariate analysis. Parent's report of vector presence showed a 97.7% sensitivity in identifying a dwelling with at least one seropositive child. The possibility of transplacental T. cruzi transmission and its implication for Chagas' disease control were considered.     

An atypical case of atypical pneumonia

A case of anomalous pancreaticobiliary union with ectopic drainage of the common bile duct into the third part of the duodenum was diagnosed in an 86-year-old woman upon evaluation of acute pancreatitis. The role of anomalous pancreaticobiliary unions in the genesis of acute pancreatitis is discussed.     

Elevated serum alkaline phosphatase level may aid in the diagnosis of pancreatitis

Ten cases of pancreatitis with elevated serum alkaline phosphatase (SAP) levels are reported. Patients with chronic or relapsing pancreatitis may at times develop increased SAP levels, either with or without definitive biochemical evidence of pancreatic disease. SAP estimation may assist in establishing a clinical diagnosis in cases of abdominal pain in which pancreatitis is suspected.     

Cholinergic amacrine cells are not required for the progression and atropine-mediated suppression of form-deprivation myopia

Expression of extracellular matrix (ECM) components during differentiation of pre-existing preadipocytes and preadipocytes recruited by dexamethasone (DEX) was examined with immunocytochemistry in primary cultures of adipose tissue stromal vascular (S-V) cells. Immunocytochemistry showed that a small proportion of preadipocytes (AD-3+) in 24-h cultures (d 0 to 1) contained lipid or expressed ECM. Two days of insulin treatment markedly increased preadipocyte ECM expression, and preadipocytes were "rounder" than those not treated with insulin. Dexamethasone with insulin increased preadipocyte recruitment two- to fivefold in completely serum-free cultures and in cultures serum-free after seeding and plating in serum for 1 to 3 d. Double staining demonstrated that ECM expression and lipid accretion were tightly coupled and lagged significantly behind preadipocyte recruitment (AD-3 expression). Double staining (lipid and AD-3) also demonstrated remarkable and unexpected cytological traits indicating a "reticuloendothelial" nature of newly recruited preadipocytes. Time-lapse phase contrast microscopy verified these observations and demonstrated that small adipocytes and preadipocytes migrated and formed cell-to-cell contacts while aggregating and clustering. Large clusters of lipid-free preadipocytes developed in DEX-treated cultures, but not in cultures treated with DEX + insulin. However, the influence of DEX on preadipocyte recruitment and ECM expression was independent of insulin. Preadipocytes on ECM substrata accumulated lipid but were "flat" and did not express ECM components, regardless of insulin or DEX treatment. These studies clearly indicate that preadipocytes express ECM components after recruitment, and the ECM may be critical for morphological development of adipocytes.     

Impaired endothelium-dependent relaxation in isolated resistance arteries of spontaneously diabetic rats

1. Previous studies have shown that endothelium-dependent relaxation in the aorta of spontaneously diabetic bio bred rats (BB) is impaired. 2. We have investigated noradrenaline (NA) contractility, endothelium-dependent acetylcholine (ACh) and bradykinin (BK) relaxation, and endothelium-independent sodium nitroprusside (SNP) relaxation in mesenteric resistance arteries of recent onset BB rats and established insulin treated BB rats, compared to their age-matched non diabetic controls. 3. There was no significant difference in the maximum contractile response or sensitivity to noradrenaline in either of the diabetic groups compared to their age-matched controls. 4. Incubation with the nitric oxide synthetase inhibitor NG-nitro-L-arginine (L-NOARG) resulted in a significant increase in maximum contractile response to noradrenaline in the recent onset age-matched control group (P < 0.05). Analysis of the whole dose-response curve (using ANOVA for repeated measures with paired t test) showed a significant left-ward shift following the addition of L-NOARG (P < 0.001). A similar but less marked shift (P < 0.01) was evident in vessels from recent onset diabetics. An overall shift in both sensitivity and maximum response was also evident in the age-matched non diabetic controls of the insulin-treated group (P < 0.05). However, by contrast, there was no significant change in sensitivity in the insulin-treated diabetic rats. 5. ACh-induced endothelium-dependent relaxation was significantly impaired in the recent onset diabetic rats compared to their age-matched controls (47 +/- 11% versus 92 +/- 2%, P < 0.05, n = 6), and in the insulin treated diabetic rats (34 +/- 5% versus 75 +/- 6%, P < 0.05, n = 6). The relaxation responses to BK also were significantly impaired in the diabetic rats compared to their age-matched controls (recent onset: 20 +/- 3% versus 72 +/- 7%, P < 0.05, n = 6; insulin treated: 12 +/- 9% versus 68 +/- 7%, P < 0.05, n = 7). 6. Incubation with either the nitric oxide synthetase substrate, U-arginine, or the free radical scavenging enzyme superoxide dismutase (150 mu ml-1) failed to improve the attenuated response of acetylcholine-induced relaxation in the diabetic vessels. 7. Endothelium-dependent relaxation mediated by ACh and BK was significantly attenuated in both the diabetic and control vessels after incubation with L-NOARG. 8. Pretreatment with a cyclo-oxygenase inhibitor, indomethacin, significantly enhanced the relaxation to ACh in both the recent onset and insulin treated diabetic rats (42 +/- 10%, n = 7 versus 64 +/- 7%, n = 7, P < 0.05, and 40 +/- 5%, n = 7 versus 65 +/- 9%, n = 6, P < 0.05). 9. Following endothelium removal, there was a marked impairment in endothelium-dependent relaxation responses to ACh and BK in both the diabetic and control vessels. 10. Incubation with the thromboxane A2 receptor antagonist SQ29548, did not significantly improve the ACh endothelium-dependent relaxation response in the diabetic vessels. 11. Endothelium-independent relaxation to sodium nitroprusside was significantly impaired in the first group of diabetic vessels studied; however, subsequent studies showed no impairment of the sodium nitroprusside response in the diabetic vessels. 12. In conclusion, the ability of the endothelium to regulate vascular contractility is reduced in recent onset diabetic vessels, and significantly impaired in established insulin treated diabetics. Relaxation to the endothelium-dependent vasodilators ACh and BK was impaired in both the recent onset and the established insulin treated diabetics, and the ACh response was significantly improved following pretreatment with indomethacin, suggesting a role for a cyclo-oxygenase-derived vasoconstrictor. Preliminary studies with a thromboxane A2, receptor antagonist, SQ29548 did not significantly improve the impaired relaxation to ACh, indicating that the vasoconstrictor prostanoid is not thromboxane A2.     

Inherited deficiency of the second component of complement (C2) with membranoproliferative glomerulonephritis

The occurrence of membranoproliferative glomerulonephritis in a 13 year old boy with inherited complete deficiency of the second component of complement (C2) is described here for the first time. Results of the complement studies and the associations of glomerulonephritis with complement deficiencies are discussed.     

Morphologic and immunohistochemical observation of explanted Proplast-Teflon temporomandibular joint interpositional implants

PURPOSE: The objective of this study was to investigate the cellular tissue response to temporomandibular joint (TMJ) Proplast-Teflon disc material by morphologic and immunohistochemical means. PATIENTS AND METHODS: Twelve patients who had been subjected to TMJ discectomy combined with insertion of a Proplast-Teflon interpositional implant (PTIPI) were recalled for removal of the alloplastic disc. The time elapsed between the Proplast-Teflon disc implantation and its removal varied between 13 and 71 months (mean, 54.6 +/- 5.8 [SEM]) The implants and periimplant tissues were examined by light microscopy and immunohistochemically using a panel of monoclonal antibodies reactive with different subclasses of leukocytes. The sections were immunostained using the alkaline phosphatase-antialkaline phosphatase (APAAP) technique. RESULTS: Fibrosis and a massive foreign body giant cell reaction were seen inside the heavily disrupted alloplastic implants and in the periimplant tissues. CD68-positive monocyte-derived cells dominated the reactive infiltrate in the implants and surrounding tissue. The CD68-positive cells also were partly positive for lysozyme. The lymphocytic infiltration contained no B cells. CONCLUSIONS: This study of the PTIPI-induced tissue reaction gave no indication of a toxic or an immunologic pathogenesis. Mechanical stress seems important in the fragmentation of the implant and induction of the foreign body reaction. It is not yet known if this fragmentation is the major contributing factor.     

Autonomic control of asystolic vasovagal syncope

A 30 year old woman with a lifelong history of severe, recurrent, vasovagal syncope became asystolic for 30 seconds after 37 minutes of 60 degrees head-up tilt. During early tilt, sympathetic activity, heart rate, left ventricular contractility, and cardiac output increased. Mean blood pressure was initially maintained. Presyncope was associated with maximal contractility and bradycardia despite sustained sympathetic activity. Subsequently, asystole occurred associated with complete withdrawal of muscle nerve sympathetic activity. In asystolic vasovagal reactions, presyncope may be triggered by increased left ventricular contractility and is associated with increased levels of parasympathetic and sympathetic activity. Asystole and peripheral vasodilatation may be caused by sudden and complete withdrawal of the increased sympathetic activity.     

An anatomical study of a new portal for ankle arthroscopy

We describe a medial midline portal between the tendons of extensor hallucis longus and tibialis anterior for arthroscopy of the ankle. We dissected 20 cadaver specimens to compare the risk of neurovascular injury using this approach with that of using standard arthroscopic portals. Compared with the anterocentral portal, the medial midline was a mean of 11.2 mm further from the nearest branch of the superficial peroneal nerve and 10.3 mm further from the dorsalis pedis artery. This portal allows good access to the joint surface and intra-articular structures and has a lower risk of injury to the dorsalis pedis artery, deep peroneal nerve or the medial branch of the superficial peroneal nerve.