Percutaneous drainage of chest abscesses in children

Seven patients ranging in age from 3 to 18 years underwent percutaneous drainage of eight intrathoracic abscesses. Five of the abscesses were mediastinal or paramediastinal and resulted from esophageal perforation or esophageal anastomotic leakage. The abscesses resolved in each case, with a mean catheter drainage time of 28 days and no need for surgical intervention. Three of the abscesses were intrapulmonary, and each lay adjacent to a pleural surface. All three lung abscesses resolved within 19-24 days, without thoracotomy or wedge resection.     

Correlation between homicide rates and economic indicators in S?o Paulo, Brazil, 1996]

Around 30% of the deaths due to violent causes in Brazil result from homicides. Violence has traditionally been related to larger social problems, such as poverty. Recently, however, a positive correlation has been observed between higher incomes and an increase in the homicide rate, so that some researchers have begun to consider inequality, rather than poverty, as an explanation for the epidemic of violence. The objective of this study was to investigate the correlation between urbanization, poverty, and economic inequality and homicide rates in the state of S?o Paulo, Brazil, in 1996. Information regarding population size, average monthly income of household heads, income distribution, and Gini index was obtained for each municipality, based on the demographic census. Homicide rates were calculated based on official data. Data were analyzed in terms of correlation and relative risk with 95% confidence intervals. Homicide rates rose in direct proportion to city population and ranged from 6.96 (per 100,000 inhabitants) in municipalities with a population smaller than 10,000 inhabitants, to 55.54 in municipalities with more than 1 million inhabitants. Relative risk ranged from 1.35 to 7.98. A significant correlation with population size was found only for incomes above 3.11 times the minimum wage and a Gini index greater than 0.50. There was a strong, direct, and significant correlation between homicide rates and the income ratio between the ninetieth and the twentieth percentiles of the population. It is necessary to probe more deeply into the macrosocial determinants of homicide rates in order to identify indicators of inequality that can generate meaningful data for developing public health strategies.     

Comparing Metal Toxicity Among Daphnia magna Clones: An Approach Using Concentration-Time-Response Surfaces

This study investigates the use of concentration-time-response surfaces as a tool to predict potential long-term effects of metals to Daphnia magna, using mortality as an endpoint. Specifically, concentration-time-response surfaces were determined for four D. magna clones exposed to four metals (Cd, Zn, Cu or U) in moderate-hard or hard synthetic freshwater for 24–96 h. Mortality data were log_e transformed into probits and then regressed against the reciprocal of exposure time and concentration. The results obtained clearly showed that mortality was markedly affected at exposure periods longer than 48 h. Thus, an optimal exposure period of 72 h was selected to compare predicted lethality effects (LC) of different intensities (i.e., 10–50%) derived from concentration-time-response surfaces with measured chronic lethal levels obtained from the literature. Only the results of Cd and Cu show good agreement between predicted and measured chronic lethal concentration levels. The apparent disagreement observed for U could be attributed to differences in water quality, and hence, U bioavailability. The high levels of Zn toxicity observed in relation to the predicted values could indicate that chronic mortality of Zn is mediated by toxic anorexia. Overall, the results obtained show that concentration-time-response surfaces offered the potential to assess the effect of time on toxicity, which is desirable to credibly extrapolate from acute to chronic scenarios. Furthermore, by determining lower mortality thresholds (i.e., LC₁₀) at different times, concentration-time-response surfaces were able to emulate the mode of action of the selected metals on chronic exposures. Therefore, the use of concentration-time-response surfaces has potential application in environmental risk assessment. Received: 7 December 1998/Accepted: 22 March 1999     

Inadvertent ligation of the left pulmonary artery

In five patients, aged 4 days to 20 months, the left pulmonary artery was inadvertently ligated at the time of attempted closure of the patent ductus arteriosus. The complication was recognized in these patients between 1 day and 5 years later from findings of chest radiography, two-dimensional echocardiography with spectral analysis of Doppler shifted echoes, and angiography. In three patients, the presence of asymmetric pulmonary blood flow on chest radiographs obtained after surgery initially suggested the diagnosis. In the other two patients with bronchopulmonary dysplasia, the diagnosis was made by means of two-dimensional echocardiography and Doppler spectra in one and angiography in the other. On angiograms, the left pulmonary artery distal to the ligation was visualized by delayed opacification from aortic collaterals in three patients and by means of pulmonary venous wedge injection in one. Radiographic and echocardiographic examination with Doppler spectra may permit prompt diagnosis and early correction of this complication.     

Head and neck lesions: MR-guided aspiration biopsy

Aspiration biopsy guided with computed tomography (CT) has long been a valuable tool in the evaluation of head and neck disease. The ability to obtain diagnoses without the need for surgery has had a significant effect on patient treatment. Magnetic resonance (MR) imaging is now rapidly replacing CT as the primary imaging study for many head and neck diseases. The standard stainless steel needles used for CT-guided biopsy are unsuitable for MR-guided biopsy because significant ferromagnetic artifacts obscure the underlying anatomy. A new needle has recently been designed specifically for use with MR imaging. This needle has far less magnetic susceptibility and therefore does not cause significant image distortion. The authors describe the use of this needle in MR-guided aspiration biopsy of a variety of lesions in the head and neck.     

Tongue and oropharynx: findings on MR imaging

Ten healthy subjects and 44 patients with diseases of the tongue or oropharynx were studied with magnetic resonance (MR) imaging. Axial, coronal, and sagittal images with a thickness of 4 mm were obtained with a pixel size of 0.75 X 0.75 mm on a 256 matrix. Nineteen of the patients underwent computed tomography (CT). Nine of those patients later had surgery, and the specimens were obtained for organ sectioning. These three studies as well as clinical history and physical examination findings were correlated. MR imaging was equal to or better than CT in those patients having both examinations. However, neither CT nor MR allowed recognition of histologic features or detection of microscopic spread of disease. Direct coronal and sagittal imaging planes on MR imaging allowed visualization of intrinsic tongue musculature, not possible with CT; this was important in recognizing subtle tumor extension. For these reasons, MR is the imaging method of choice for studying diseases of the tongue and oropharynx.     

Effacement of the fetal cisterna magna in association with myelomeningocele

The cisterna magna is effaced in association with myelomeningocele. The authors retrospectively investigated the size of the fetal cisterna magna as a predictor of fetal myelomeningocele in 67 pregnant women (17-38 menstrual weeks) referred for prenatal sonography because of an elevated serum alpha-fetoprotein level (n = 61) or a suspicion of fetal ventriculomegaly on previously obtained sonograms (n = 6). Twenty fetuses had myelomeningocele, 14 had isolated ventriculomegaly, and 33 were normal. A normal-sized cisterna magna (range, 4-9 mm in depth) was present in all normal fetuses. In 19 of 20 fetuses with myelomeningocele, the views of the posterior fossa were adequate, and in each of these the cisterna magna was effaced (n = 18) or very small (n = 1). The cisterna magna was effaced in five of 13 (38%) fetuses with isolated ventriculomegaly in whom the posterior fossa was adequately imaged. Although effacement of the cisterna magna is a nonspecific finding, the high negative predictive value of this sign is useful during routine screening of the fetal neural axis.     

Simultaneous confirmation and differentiation of human T-lymphotropic virus types I and II infection by modified western blot containing recombinant envelope glycoproteins

A modified Western blot (WB) that includes both shared (r21e) and unique recombinant envelope proteins from human T-lymphotropic virus (HTLV) type I (rgp46I) and type II (rgp46II) was compared to conventional HTLV serologic tests in 379 United States blood donors and individuals residing in diverse geographic regions, and the specimens were categorized as positive (n = 158), indeterminate (n = 158), or negative (n = 63) for HTLV infection. Of the 158 HTLV-I/II-positive specimens (66 requiring radioimmunoprecipitation assay [RIPA] for confirmation), 156 reacted concordantly with r21e, gag, and either rgp46I or rgp46II, thus eliminating the need for RIPA in all but two specimens and yielding a test sensitivity of 98.7 percent. Of the 158 indeterminate and 63 negative specimens, none reacted with r21e and rgp46I or rgp46II, yielding a test specificity of 100 percent. Furthermore, analysis of an additional 184 consecutive specimens from a retrovirology reference laboratory demonstrated that the modified WB correctly identified 27 of 28 HTLV-I specimens and all 13 HTLV-II specimens, with a test sensitivity of 97.6 percent. None of specimens that were indeterminate or nonreactive in conventional WB and/or RIPA and none of the screening enzyme immunoassay-negative specimens reacted with r21e and either rgp46I or rgp46II, for a test specificity of 100 percent. Thus, the modified WB appears to be highly sensitive and specific for simultaneous detection and discrimination of HTLV-I from HTLV-II and has the advantage of being a one-step assay that is easily performed in all types of laboratory settings and allows rapid, reliable, and standardized testing for HTLV-I/II infection.