The Moraceae-based dart poisons of South America. Cardiac glycosides of Maquira and Naucleopsis species.

The use of cardenolide-containing Moraceae in the dart poisons of South America is reviewed. Those prepared by the Chocó Indians of western Colombia--called niaará or kieratchi--have probably been made from the latex of Naucleopsis amara and N. glabra. In Ecuador, the Colorado Indians used N. chiguila, while the Coaiquer Indians still derive a poison from the latex of N. naga and the Cayapá Indians occasionally make use of a blowgun poison, hambi, which probably also comes from a Naucleopsis species. The Kaborí (Rio Uneiuxi Makú) Indians of north-western Brazil may have utilized Maquira coriacea, but a more recent collection documents N. mello-barretoi latex as a source of their poison. The Tikuna Indians of western Brazil included leaves and bark of N. stipularis in one of their poisons. The principal cardiac glycosides present in Maquira species are strophanthidin-based and the main ones occurring in Naucleopsis species are antiarigenin- as well as strophanthidin-based. The structures of two new glycosides, isolated from dart-poison samples, have been established as strophanthidin beta-D-glucomethylosido-D-alloside and beta-D-digitoxosido-D-alloside. The former is a major component of pakurin, the crystalline glycoside mixture prepared by Santesson in 1928 from a Chocó Indian poison.     

HIV-1 p24 antigen is a significant inverse correlate of CD4 T-cell change in patients with suppressed viremia under long-term antiretroviral therapy

An HIV-1 p24 antigen test involving signal amplification-boosted ELISA of heat-denatured plasma was evaluated prospectively in 55 patients whose viral RNA in plasma had previously been suppressed for at least 6 months under antiretroviral combination therapy. During a median follow-up of 504 days, CD4 counts increased by a median of 62 cells per year. By univariate and multivariate linear regression analysis, the level of p24 antigen as expressed by the absorbance/cutoff ratio was a significant inverse correlate of both the CD4 count in a sample (p =.013) and its annual change in a patient (p <.0001). The p24 antigen retained significance even among 48 individuals whose HIV-1 RNA, apart from occasional blips, remained below 400 copies/mL. Batch-wise retesting of 70 samples from 5 such patients with a further improved procedure showed measurable p24 antigen in all but 1 sample and an inverse correlation with both the CD4 count (p =.0331) and percentage (p <.0001), thus confirming the prospectively generated data. Comparison of p24 antigen and HIV-1 RNA concentrations indicate that the p24 antigen detected in these samples is not associated with viral RNA-containing particles and may originate from other compartments of virus expression.     

Linkage of chromosome 13q32 to schizophrenia in a large veterans affairs cooperative study sample

Several prior reports have suggested that chromosomal region 13q32 may harbor a schizophrenia susceptibility gene. In an attempt to replicate this finding, we assessed linkage between chromosome 13 markers and schizophrenia in 166 families, each with two or more affected members. The families, assembled from multiple centers by the Department of Veterans Affairs Cooperative Studies Program, included 392 sampled affected subjects and 216 affected sib pairs. By DSM-III-R criteria, 360 subjects (91.8%) had a diagnosis of schizophrenia and 32 (8.2%) were classified as schizoaffective disorder, depressed. The families had mixed ethnic backgrounds. The majority were northern European-American families (n = 62, 37%), but a substantial proportion were African-American kindreds (n = 60, 36%). Chromosome 13 markers, spaced at intervals of approximately 10 cM over the entire chromosome and 2-5 cM for the 13q32 region were genotyped and the data analyzed using semi-parametric affected only linkage analysis. For the combined sample (with race broadly defined and schizophrenia narrowly defined) the maximum LOD score was 1.43 (Z-score of 2.57; P = 0.01) at 79.0 cM between markers D13S1241 (76.3 cM) and D13S159 (79.5 cM). Both ethnic groups showed a peak in this region. The peak is within 3 cM of the peak reported by Brzustowicz et al. [1999: Am J Hum Genet 65:1096-1103].     

Chronic avulsive injury of the deltoid insertion in adolescents: imaging findings in three cases

The clinical and imaging (magnetic resonance [MR] imaging, radiography, and bone scintigraphy) findings in three adolescent boys with chronic avulsive injury at the deltoid insertion are presented. MR imaging enabled the exclusion of findings suggestive of malignancy and the localization of abnormalities to the deltoid insertion site. Findings included cortical thickening and irregularity of the deltoid tubercle, with or without adjacent soft-tissue edema.     

Heterogeneous splenic enhancement patterns on spiral CT images in children: minimizing misinterpretation

PURPOSE: To (a) determine the appearances and timing of heterogeneous splenic enhancement at spiral computed tomography (CT) and (b) identify variables influencing heterogeneous splenic enhancement. MATERIALS AND METHODS: Sequential isolevel (24-mAs) CT images of the spleen obtained at 6-second intervals after initiation of contrast material injection in 112 children (mean age, 4.5 years) were reviewed. Heterogeneity characteristics assessed included type, onset, maximum, and resolution. Relationship to variables (injection rate, age, splenomegaly) was assessed with the Fisher exact test. RESULTS: Eighty-one of the 112 patients (72%) had transient heterogeneity: archiform (45 patients), diffuse (25 patients), and focal (11 patients). Mean times were as follows: initial visualization after onset of contrast material injection, 19.2 seconds; maximum heterogeneity, 27.3 seconds; and resolution, 47.4 seconds. Statistically significant relationships were seen between frequency of heterogeneity and injection rate (> or = 1 mL/sec, 82%; < 1 mL/sec, 50% [P = .001]), age (> 1 year, 76%; < or = 1 year, 46% [P = .04]), and splenomegaly (present, 20%; absent, 77% [P = .048]). CONCLUSION: Heterogeneous splenic contrast enhancement is common, has several patterns of appearance, and is predictably encountered during the 70 seconds after the initiation of contrast material injection. Injection rate, age, and presence of splenic disease influence the frequency with which these artifacts are encountered.     

Optimizing contrast-enhanced abdominal CT in infants and children using bolus tracking

OBJECTIVE: Manual administration of IV contrast material results in unpredictable injection rates. Our purpose was to determine the effect of bolus tracking on overall abdominal helical CT scan quality, particularly on hepatic enhancement, in children with manually administered contrast media. MATERIALS AND METHODS: We compared 33 abdominal helical CT scans of 29 children in whom bolus tracking was used with 22 CT scans of a control group of 21 children in whom bolus tracking was not used. All contrast material was administered by manual injection. Qualitative assessment was made of organ and vessel enhancement and overall scan appearance. Quantitative assessment using region-of-interest cursors was performed at three anatomic levels, and the results for the two groups of children were compared. RESULTS: Qualitative comparison of enhancement parameters between the bolus tracking group (number given first) and the control group (number given second) yielded the following: splenic artifact in 9% versus 23% (p = .24); inferior vena cava flow artifact in 3% versus 27% (p = .01); scanning during the nephrographic phase in 89% versus 59% (p = .02); and good quality grade in 79% versus 64% (p = .23). Significantly greater hepatic enhancement (as measured in mean Hounsfield units) was achieved in the bolus tracking group than in the control group at the superior (48.5 versus 28.6; p < .001), middle (47.9 versus 32.3; p < .001), and inferior (48.2 versus 36.5; p = .01) levels. Hepatic enhancement increased significantly from the superior to the inferior level in the control group (p < .02), whereas enhancement was homogeneous in the bolus tracking group (p > .50). CONCLUSION: Bolus tracking provides improved contrast enhancement, including significantly greater hepatic enhancement, during abdominal helical CT in children in whom the rate of injection of contrast material is unpredictable.