Automatic semantic segmentation of the lumbar spine: Clinical applicability in a multi-parametric and multi-center study on magnetic resonance images

Significant difficulties in medical image segmentation include the high variability of images caused by their origin (multi-center), the acquisition protocols (multi-parametric), the variability of human anatomy, illness severity, the effect of age and gender, and notable other factors. This work addresses problems associated with the automatic semantic segmentation of lumbar spine magnetic resonance images using convolutional neural networks. We aimed to assign a class label to each pixel of an image, with classes defined by radiologists corresponding to structural elements such as vertebrae, intervertebral discs, nerves, blood vessels, and other tissues. The proposed network topologies represent variants of the U-Net architecture, and we used several complementary blocks to define the variants: three types of convolutional blocks, spatial attention models, deep supervision, and multilevel feature extractor. Here, we describe the topologies and analyze the results of the neural network designs that obtained the most accurate segmentation. Several proposed designs outperform the standard U-Net used as a baseline, primarily when used in ensembles, where the outputs of multiple neural networks are combined according to different strategies.

Effects of Mn supplementation in late-gestating and lactating red deer (Cervus elaphus hispanicus) on milk production, milk composition, and calf growth

This study describes the effects of Mn supplementation of 20 late-gestating and lactating Iberian red deer (Cervus elaphus hispanicus) females (hinds) fed a balanced diet on milk production and milk composition over the lactation period. Body weight of their calves at birth and at weaning was also evaluated. In addition, the effect of lactation stage was studied. For these purposes, 2 groups of hinds, one composed by 12 individuals (experimental) and the other by 8 individuals (control) were compared. Experimental hinds were s.c. injected weekly with Mn (2 mg Mn/kg BW) from day 140 of gestation until the end of lactation (week 18; forced weaning by physical separation). Control hinds were injected with a physiological saline solution with the same volume and at the same frequency as the experimental group. Serum Mn content of hinds was assessed just before the first Mn injection and at week 10 of lactation to assess whether the injected Mn increased Mn concentrations in blood. No differences were observed for BW of calves at birth but calves whose mothers were injected with Mn tended (P = 0.07) to have greater gain of BW from birth to weaning in proportion of BW at birth compared to calves from control hinds. In addition, supplementation with Mn increased (P ≤ 0.05) daily milk production by 10.2%, milk fat content by 11.2%, and total fat yield by 17.8%. Also, milk from hinds supplemented with Mn had more Ca (P < 0.001) and P (P < 0.05) than milk from control hinds. Manganese supplementation did not influence Mn serum content when blood was analyzed at week 10 of lactation, but increased the Mn content of milk by 18.3% (P < 0.001). Lactation stage affected (P < 0.001) fat, protein, lactose, and DM. Their contents increased as lactation proceeded, and protein was substituted by fat. Therefore, results suggest that Mn supplementation of hinds is recommended, even when they are fed a balanced diet, to increase milk production and the content of fat, Ca, P, and Mn of milk.

The anti-CD6 antibody itolizumab provides clinical benefit without lymphopenia in rheumatoid arthritis patients: results from a 6-month, open-label Phase I clinical trial

Itolizumab is a humanized anti-CD6 monoclonal antibody (mAb) that has previously shown encouraging results, in terms of safety and positive clinical effects, in a 6-week monotherapy clinical trial conducted in rheumatoid arthritis (RA) patients. The current Phase I study evaluated the safety and clinical response for a longer treatment of 12 itolizumab intravenous doses in subjects with active RA despite previous disease-modifying anti-rheumatic drug (DMARD) therapy. Twenty-one subjects were enrolled into four dosage groups (0·1, 0·2, 0·4 and 0·8 mg/kg). Efficacy end-points including American College of Rheumatology (ACR)20, ACR50 and ACR70 response rates and disease activity score in 28 joints (DAS28) were monitored at baseline and at specific time-points during a 10-week follow-up period. Itolizumab was well tolerated up to the highest tested dose. No related serious adverse events were reported and most adverse events were mild. Remarkably, itolizumab treatment did not produce lymphopenia and, therefore, was not associated with infections. All patients achieved a clinical response (ACR20) at least once during the study. Eleven subjects (55%) achieved at least a 20% improvement in ACR just 1 week after the first itolizumab administration. The clinical response was observed from the beginning of the treatment and was sustained during 24 weeks. The efficacy profile of this 12-week treatment was similar to that of the previous study (6-week treatment). These results reinforce the safety profile of itolizumab and provide further evidence on the clinical benefit from the use of this anti-CD6 mAb in RA patients.

Numerical modeling of fiber specklegram sensors by using finite element method (FEM)

Although experimental advances in the implementation and characterization of fiber speckle sensor have been reported, a suitable model to interpret the speckle-pattern variation under perturbation is desirable but very challenging to be developed due to the various factors influencing the speckle pattern. In this work, a new methodology based on the finite element method (FEM) for modeling and optimizing fiber specklegram sensors (FSSs) is proposed. The numerical method allows computational visualization and quantification, in near field, of changes of a step multi-mode fiber (SMMF) specklegram, due to the application of a uniformly distributed force line (UDFL). In turn, the local modifications of the fiber speckle produce changes in the optical power captured by a step single-mode fiber (SSMF) located just at the output end of the SMMF, causing a filtering effect that explains the operation of the FSSs. For each external force, the stress distribution and the propagations modes supported by the SMMF are calculated numerically by means of FEM. Then, those modes are vectorially superposed to reconstruct each perturbed fiber specklegram. Finally, the performance of the sensing mechanism is evaluated for different radius of the filtering SSMF and force-gauges, what evidences design criteria for these kinds of measuring systems. Results are in agreement with those theoretical and experimental ones previously reported.

Experimental assessment of gold nanoparticle-mediated dose enhancement in radiation therapy beams using electron spin resonance dosimetry

In this work, we aim to experimentally assess increments of dose due to nanoparticle-radiation interactions via electron spin resonance (ESR) dosimetry performed with a biological-equivalent sensitive material.We employed 2-Methyl-Alanine (2MA) in powder form to compose the radiation sensitive medium embedding gold nanoparticles (AuNPs) 5 nm in diameter. Dosimeters manufactured with 0.1% w/w of AuNPs or no nanoparticles were irradiated with clinically utilized 250 kVp orthovoltage or 6 MV linac x-rays in dosimetric conditions. Amplitude peak-to-peak (App) at the central ESR spectral line was used for dosimetry. Dose-response curves were obtained for samples with or without nanoparticles and each energy beam. Dose increments due to nanoparticles were analyzed in terms of absolute dose enhancements (DEs), calculated as App ratios for each dose/beam condition, or relative dose enhancement factors (DEFs) calculated as the slopes of the dose-response curves.Dose enhancements were observed to present an amplified behavior for small doses (between 0.1-0.5 Gy), with this effect being more prominent with the kV beam. For doses between 0.5-5 Gy, dose-independent trends were observed for both beams, stable around (2.1   ±   0.7) and (1.3   ±   0.4) for kV and MV beams, respectively. We found DEFs of (1.62   ±   0.04) or (1.27   ±   0.03) for the same beams. Additionally, we measured no interference between AuNPs and the ESR apparatus, including the excitation microwaves, the magnetic fields and the paramagnetic radicals.2MA was demonstrated to be a feasible paramagnetic radiation-sensitive material for dosimetry in the presence of AuNPs, and ESR dosimetry a powerful experimental method for further verifications of increments in nanoparticle-mediated doses of biological interest. Ultimately, gold nanoparticles can cause significant and detectable dose enhancements in biological-like samples irradiated at both kilo or megavoltage beams.

Generation of optical vortices by using binary vortex producing lenses

Experimental high-quality optical vortices of different topological charges are generated by using a vortex producing lens with two phase levels. In our setup, the lens is displayed on a liquid-crystal spatial light modulator that only attains phase modulation of around 1.2π. This achievement opens the real possibility of creating high-quality optical vortices with devices of very low phase modulation capacity. The experimental setup is fully described, and the considerations to set the optimal parameters to obtain high-quality optical vortices are discussed and experimentally established. The phase and intensity of the optical vortices are recovered. The phase is obtained through a phase-shifting method that is directly programmed onto the modulator avoiding any class of mechanical displacement.

Soil factors involved in the diversity and structure of soil bacterial communities in commercial organic olive orchards in Southern Spain

Nowadays, there is a tendency in olive production systems to reduce tillage or keep a vegetative cover to reduce soil erosion and degradation. However, there is scarce information on the effects of different soil management systems (SMS) in soil bacterial community composition of olive groves. In this study, we have evaluated the effects of soil type and different SMS implemented to control weeds in the structure and diversity of bacterial communities of 58 soils in the two geographic areas that best represent the organic olive production systems in Spain. Bacterial community composition assessed by frequency and intensity of occurrence of terminal restriction profiles (TRFs) derived from terminal restriction fragment length polymorphism (T-RFLP) analysis of amplified 16S ribosomal deoxyribonucleic acid were strongly correlated with soil type/field site (Eutric/Calcaric) that differed mainly in soil particle size distribution and soil pH, followed by a strong effect of SMS, in that order. Canonical discriminant (CD) analysis of TRFs properly classified all of the olive orchard soils as belonging to their respective soil type or SMS. Furthermore, only a small set of TRFs were enough to clearly and significantly differentiate soil samples according to soil type or SMS. Those specific TRFs could be used as bioindicators to assess the effect of changes in SMS aimed to enhance soil quality in olive production systems.

3D prostate histology reconstruction: an evaluation of image-based and fiducial-based algorithms

PURPOSE

Evaluation of in vivo prostate imaging modalities for determining the spatial distribution and aggressiveness of prostate cancer ideally requires accurate registration of images to an accepted reference standard, such as histopathological examination of radical prostatectomy specimens. Three-dimensional (3D) reconstruction of prostate histology facilitates these registration-based evaluations by reintroducing 3D spatial information lost during histology processing. Because the reconstruction accuracy may constrain the clinical questions that can be answered with these data, it is important to assess the tradeoffs between minimally disruptive methods based on intrinsic image information and potentially more robust methods based on extrinsic fiducial markers.

METHODS

Ex vivo magnetic resonance (MR) images and digitized whole-mount histology images from 12 radical prostatectomy specimens were used to evaluate four 3D histology reconstruction algorithms. 3D reconstructions were computed by registering each histology image to the corresponding ex vivo MR image using one of two similarity metrics (mutual information or fiducial registration error) and one of two search domains (affine transformations or a constrained subset thereof). The algorithms were evaluated for accuracy using the mean target registration error (TRE) computed from homologous intrinsic point landmarks (3-16 per histology section; 232 total) identified on histology and MR images, and for the sensitivity of TRE to rotational, translational, and scaling initialization errors.

RESULTS

The algorithms using fiducial registration error and mutual information had mean ± standard deviation TREs of 0.7 ± 0.4 and 1.2 ± 0.7 mm, respectively, and one algorithm using fiducial registration error and affine transforms had negligible sensitivities to initialization errors. The postoptimization values of the mutual information-based metric showed evidence of errors due to both the optimizer and the similarity metric, and variation of parameters of the mutual information-based metric did not improve its performance.

CONCLUSIONS

The extrinsic fiducial-based algorithm had lower mean TRE and lower sensitivity to initialization than the intrinsic intensity-based algorithm using mutual information. A model relating statistical power to registration error for certain imaging validation study designs estimated that a reconstruction algorithm with a mean TRE of 0.7 mm would require 27% fewer subjects than the method used to initialize the algorithms (mean TRE 1.3 ± 0.7 mm), suggesting the choice of reconstruction technique can have a substantial impact on the design of imaging validation studies, and on their overall cost.

High-quality optical vortex-beam generation by using a multilevel vortex-producing lens

In the present work, we propose a method to generate high-quality optical vortices with a reduced number of phase levels by using multilevel vortex-producing lenses (VPLs). The VPL is implemented in a liquid-crystal spatial light modulator with limited capacity to project phase levels. The proposed method significantly improves the quality of the optical vortex obtained by employing spiral phase plates with the same number of phase levels. Simulations and experimental results confirming the effectiveness of the method are presented.

Influence of dental restorative materials on ESR biodosimetry in tooth enamel

Using an experimental model and PENELOPE Monte Carlo simulations, the effects of resin and amalgam on the absorbed doses in tooth enamel were studied to evaluate the feasibility of using restored teeth in electron spin resonance (ESR) dose reconstruction. The model consisted of a phantom containing a plate of these restorative materials placed between powered enamel layers exposed to X rays and a ⁶⁰Co beam. The experimental results and simulations agreed, showing that the attenuation produced by amalgam and resin with a thickness of 1, 2, and 4 mm is similar to that produced by the enamel itself in the case of the radiation sources employed. For X rays and ⁶⁰Co γ radiation the attenuation reached almost 100% and 40%, respectively. These results show that for ESR dose reconstruction, the use of all available enamel of a tooth leads to errors in the estimated dose due to attenuation effects in both healthy and restored teeth. Thus the importance of an enamel selection from different sides of the tooth surface to apply ESR dose reconstruction in the case of a practical situation is shown.

Effect of milk minerals on calf gains and sex differences in mineral composition of milk from Iberian red deer (Cervus elaphus hispanicus)

Milk mineral content has received little attention in studies focusing on milk nutrient effects on offspring growth. This study examines calf growth in Iberian deer and compares the influence of milk minerals, other nutrients, and lactation variables relevant for growth to discern the relative weight of each factor. In addition, because Iberian deer hinds are the first mammal found to produce different milk for sons and daughters, the present study examines whether there are also sex differences in milk mineral composition. Concentrations and yields of Ca, P, Mg, Na, K, Fe, and Zn in milk of 46 red deer hinds were monitored through 18 weeks of lactation. Calf growth was influenced by Ca and P percent, and total Fe production. Milk for males had a lower content in Ca and P, a greater content of K, and Mg, whereas no sex effects were found in Na, Fe, or Zn percentages. Higher percentages in Ca and P for daughters might constitute a compensatory response, as daily production was not biased towards females in Ca or P, whereas in the latter and all the other minerals daily production was greater for heavier calves, which are usually males. In conclusion, milk mineral content and production influence calf growth even after controlling for other important lactation variables and nutrients, and they show effects and interactions more complicated than expected.

Pancreas transcription factor 1alpha expression is regulated in pancreatitis

BACKGROUND

Expression of acinar cell-specific genes requires the pancreas transcription factor 1alpha (Ptf1alpha). p48 is the only component of Ptf1alpha that is involved in both acinar gene regulation and pancreatic ontogenesis.

MATERIALS AND METHODS

To determine whether Ptf1alpha/p48 expression is regulated during pancreatitis, acute pancreatitis was induced in rats by repeated caerulein injections; early chronic pancreatitis by the combined administration of caerulein and cyclosporin A; and focal pancreas fibrosis by trinitrobenzene sulfonic acid infusion into the pancreatic duct. AR42J cells were used to examine caerulein effects on acinar cells. Ptf1alpha/p48 expression was examined using immunohistochemistry, Western blotting, and qRT-PCR methods.

RESULTS

In acute pancreatitis, Ptf1alpha/p48 decreased markedly within 6 h as determined by Western blotting and immunohistochemistry. After 24 h, Ptf1alpha/p48 increased continuously and normalized at day six. In contrast, pancreas amylase reached a nadir at 48 h, when Ptf1alpha/p48 had largely recovered. In the early chronic pancreatitis model Ptf1alpha/p48 levels did not completely recover even at day 14, and this was associated with a failure to restore normal histology and amylase content. qRT-PCR showed that p48 mRNA were reduced after pancreatitis induction and were followed by a decrease in elastase mRNA. In the focal pancreas fibrosis model, Ptf1alpha/p48 expression was undetectable in areas with substantial acinar cell loss and tubular complexes. Caerulein did not affect Ptf1alpha/p48 expression in AR42J cells.

CONCLUSIONS

Ptf1alpha/p48 protein and mRNA levels are regulated in acute and chronic experimental pancreatitis. Inability to re-express Ptf1alpha/p48 after injury may preclude acinar cell differentiation and appropriate pancreatic regeneration.

Influence of disodium malate on microbial growth and fermentation in rumen-simulation technique fermenters receiving medium- and high-concentrate diets

Two incubation trials were carried out with the rumen-simulation technique (RUSITEC). In each trial, four vessels received a diet of grass hay and concentrate (600 and 400 g/kg DM, respectively; diet F), and the other four were fed a diet composed of concentrate and barley straw (900 and 100 g/kg DM, respectively; Diet C). Vessels were given 20 g of the corresponding diet daily, and half of them were supplemented with disodium malate to achieve a final concentration of 6.55 mM. There were no effects (P>0·05) of malate either on pH or on the daily production of NH3-N, but malate treatment increased (P<0·05) DM, neutral detergent and acid detergent fibre disappearance after 48 h incubation. The daily production of propionate and butyrate increased (P<0·001), and the ratio CH4:volatile fatty acids decreased (P<0·001) by supplementing both diets with malate. Whereas adding malate to the F diet produced an increase in acetate production (P=0·011) and the growth of solid-associated micro-organisms (P=0·037), no effects (P>0·05) were observed for diet C. For both diets, there were no differences (P>0·05) between treatments in the daily flow of liquid-associated micro-organisms measured using15N as a microbial marker. These results indicate that malate stimulated thein vitrofermentation of both diets by increasing the apparent disappearance of the diet and decreasing the ratio of CH4:volatile fatty acids, but a greater response was observed with diet F. If these results are confirmedin vivo, malate could be used as a feed additive for ruminants fed diets containing medium proportions of forage (i.e. dairy animals) and not only in animals fed high-concentrate diets, as has so far been proposed.

Effect of radial-electric-field polarity on wire-array Z-pinch dynamics

The formation of plasma in wire-array Z-pinch experiments was found to depend upon the polarity of the radial-electric field near the wires. Reversing the radial-electric field midway along the length of an array resulted in the ablation rate of one-half of the array being reduced by 50%, significantly delaying the start of its implosion and altering its acceleration towards the axis. The observed phenomena cannot be explained by the standard magnetohydrodynamic models of array behavior, suggesting that effects such as electron emission may be important, especially during wire initiation.

[Direct and indirect labeling with 99mTc of an antireceptor monoclonal antibody of EGF]

INTRODUCTION

Radiolabeled monoclonal antibodies (MAbs) have been a useful tool for diagnostic imaging and therapy in Oncology. The aim of this study was to carry out the indirect 99mTc radiolabeling of ior egf/r3, monoclonal antibody (MAb) specific for epidermal growth factor (EGF) receptor, and the comparison with a direct 99mTc radiolabeling approach.

MATERIAL AND METHODS

Cyclic anhydride of the diethylenetriaminepentaacetic acid (ADTPA) was employed as bifunctional chelating agent in the indirect monoclonal antibody radiolabeling and it was coupled to MAb at molar ratios of 20:1, 50:1 and 200:1 (ADTPA:MAb). For the direct radiolabeling, the reduction of MAb was performed with 2-mercaptoethanol (2ME), based on Schwarz's method. Biological activity was measured by Flow Cytometry. Biodistribution studies were performed at 1, 3 and 24 h after injection of the radiolabeled antibody in Wistar rats.

RESULTS

After 30 min of 99mTc radiolabeling of the ior egf/r3 MAb, the radiochemical purity values were between 80.0 +/- 1.8 and 90.0 +/- 1.2 % for the indirect method using ADTPA, while it was 94.8 +/- 1.6 % for the direct approach using 2ME. Stability of the 99mTc-radiopharmaceuticals was similar for both methods. The biological activity was similar for both antibody formulations. There were no significant differences for the biodistribution to normal organs for both radiolabeled antibodies.

CONCLUSIONS

Use of ADTPA was shown to be an efficient method for the 99mTc labeling of the monoclonal antibody ior egf/r3. Radiolabeling using 2ME showed higher radiochemical purity.

Lactation under induced five-month delay reproduction in Iberian red deer (Cervus elaphus hispanicus)

In Iberian deer, calf birth date affects both milk production and composition, as well as the weight change of hind during lactation and calf growth. This study examines a five-month induced delay in calving (autumn group) in a group of 19 Iberian hinds compared to a group of 13 standard calving hinds (spring group). Fertility in the autumn group was half that of the spring one. From the former, a further two calves out of six died before or soon after birth. Successfully lactating hinds showed a greater concentration in protein, fat and lactose (P < 0.001), but did not differ from spring group in total milk yield, calf gain or weight change of hinds during lactation. However, after correcting for the greater calf or hind body weight at calving of the autumn group, this group showed lower values for these variables than the spring group. Results show that at least in Iberian deer, counter-season reproduction is possible, and that the effects on lactation variables are similar to those of a natural delay in calving.

Surveillance for rotavirus in Argentina

Group A rotaviruses are the major cause of severe gastroenteritis in young children worldwide. Because rotavirus vaccination appeared imminent, a nationwide surveillance program was organized between October 1996 and October 1998 in the largest Argentine cities. Surveillance for disease burden, rotavirus detection, and rotavirus typing was undertaken at nine locations. Results showed rotavirus to be associated with 42% of diarrhea admissions. Although the prevalent G types changed from year to year, common G types were found in 96% of the cases and were usually associated with common P types. Uncommon G types, G9 and G5, were found at low prevalence and uncommon G/P combinations occurred at almost every study site. These data suggest that a rotavirus vaccine could substantially decrease the rotavirus disease burden in Argentina, but that introduction of a vaccine should be accompanied by a concurrent surveillance system.

[Rotavirus diarrhea. Impact in a pediatric hospital of Buenos Aires]

Anticipating the use of the rotavirus vaccine, we performed this study in order to estimate the rotavirus disease burden in a pediatric hospital. We studied 648 children < 3 years of age between September/97 and August/98, assisted at the Outpatient Diarrhea Unit, or hospitalized due to acute diarrhea in our Hospital. We found rotavirus associated to 36% of the diarrhea cases studied in the Outpatient Clinics, and in 45% of the hospitalized children. We estimate the assistance of 1674 rotavirus diarrheas per year in the Outpatient Clinics, but only 14 of them required hospitalization. The study describes a peak of rotavirus diarrheas between March and June, and another peak of rotavirus-negative diarrheas between January and March (probably due to bacterial diarrheas). Rotavirus disease presented a higher frequency between 6 to 23 months of age; only 10% of the 233 rotavirus cases occurred in children older than 24 months and 13% in infants less than 6 months of age. The situation described is significant because the recently licensed rotavirus vaccine is being used in 3 doses at 2, 4 and 6 months and could have prevented most of the rotavirus cases observed during this study.

Modulation of myogenic differentiation in a human rhabdomyosarcoma cell line by a new derivative of 5-fluorouracil (QF-3602)

The in vitro study of mechanisms involved in drug-induced maturation has made it possible to use differentiation-based therapy in clinical practice. The goal of this new therapy is the development of specific agents to induce cancer cells to stop proliferating and express characteristics of normal cells. Recently, by structural modifications of 5-fluorouracil (5-FU), we synthesized a new pyrimidine acyclonucleoside-like compound, 1-¿[3-(3-chloro-2-hydroxypropoxy)-1-methoxy]propyl¿-5-fluorouracil (QF-3602), which showed in rhabdomyosarcoma cells a low toxicity and time-dependent growth inhibition. In this work, we compared the degree of myogenic differentiation of RD rhabdomyosarcoma (RMS) cells after treatment with QF-3602 and 5-FU. Scanning and transmission electron microscopy (SEM and TEM) and immunocytochemical analyses showed that QF-3602 induced the appearance of myofilaments along the myotube-like giant RD cells, an increase in fibronectin and a decrease in vimentin expression. In contrast, only minor changes were observed with 5-FU. Moreover, polymerase chain reaction (PCR) analyses showed that QF-3602 did not induce overexpression of the mdr 1 gene, a resistance mechanism that frequently appears in classical cytotoxic therapy in these tumors. Compounds obtained by structural modifications of 5-FU may be useful in differentiation therapy as a new approach to the treatment of RMS.

Phakomatous choristoma: a case report and review of the literature

Phakomatous choristoma is a rare congenital lesion of the eyelid that can be clinically and/or histologically mistaken for a cyst, cutaneous adnexal neoplasm, or an ocular adnexal oncocytoma. Only 13 such cases have been previously described, mostly in the English language ophthalmic literature. Zimmerman reported the first case in 1971 and proposed the lesion to be of lenticular anlage origin, a theory that has been widely accepted. We report an additional case occurring in an 8-week-old male infant with a firm nodule of the right lower eyelid that was present since birth. A 15 x 12 x 2 mm circumscribed solid nodule with a homogenously white cut surface was surgically excised. Histologically, this lesion was comprised of cuboidal cells forming cystically dilated and irregularly branched ducts and cords within a densely fibrotic stroma. Also present were eosinophilic basement membranelike material, psammoma body-like calcifications and intraluminal degenerated ghost cells. The immunohistochemical profile of the epithelial cells included strong immunoreactivity for vimentin, focal weak staining for S-100, and negative staining for cytokeratin, epithelial membrane antigen, synaptophysin, and chromogranin. The irregularity of the ducts and cords of epithelial cells within the densely fibrotic stroma resembled an infiltrative neoplasm of cutaneous adnexal or lacrimal duct origin. However, the site of involvement, the peculiar basement membrane material, ghost cells, and immunohistochemical profile were features that helped to distinguish phakomatous choristoma from an infiltrative carcinoma. The correct identification of this lesion is essential to avoid an aggressive surgical excision, thus sparing the eyelid and lacrimal system. The purpose of this article is to bring attention to this rare entity, because it has not been described in either the dermatology or dermatopathology literature and furthermore, is not mentioned in any of the major dermatopathology texts.

Immunohistochemical profile of myogenin and MyoD1 does not support skeletal muscle lineage in alveolar soft part sarcoma

BACKGROUND

The histogenesis of alveolar soft part sarcoma remains elusive. Myogenic origin is favored, although conflicting data on immunohistochemical demonstration of muscle-associated markers exist. Myogenin and MyoD1, transcription factors of the myogenic determination family, have crucial roles in commitment and differentiation of mesenchymal progenitor cells to myogenic lineage and in maintenance of skeletal muscle phenotype. Their immunohistochemical detection is specific in characterization of rhabdomyosarcoma.

METHODS

Antibodies for myogenin, MyoD1, desmin, and muscle-specific actin were employed on a large series of cases (n = 19) of formalin-fixed, paraffin-embedded alveolar soft part sarcoma.

RESULTS

Minimal scattered nuclear staining was seen with myogenin. All cases had pronounced, nonspecific granular cytoplasmic immunostaining with MyoD1; nuclei were negative. All tumors were negative for desmin and muscle-specific actin. Ultrastructural study in 10 cases failed to reveal features of skeletal muscle differentiation.

CONCLUSIONS

Cytoplasmic staining with MyoD1 in alveolar soft part sarcoma may correspond to cross-reactivity with an undetermined cytoplasmic antigen. The lack of immunostaining with myogenin, MyoD1, desmin, and muscle-specific actin provides evidence against a myogenic origin for alveolar soft part sarcoma.

The neisserial 37 kDa ferric binding protein (FbpA)

The ferric binding protein (FbpA) is one of the major proteins regulated by the level of environmental iron in the genus Neisseria. Its conservation in all species of pathogenic Neisseria has been demonstrated, and the possible role that it plays in the iron uptake mechanisms in these bacteria has been postulated. Similar proteins in Haemophilus influenzae (HitA) and in Serratia marcescens (SfuA) have been described, but relationships with the meningococcal FbpA could not be proven. Although supposedly periplasmic, the exact location of FbpA remains controversial because some molecules, or parts of them, have been found exposed to the bacterial outer surface. The DNA sequence downstream of the fbpA gene has been recently analysed, finding an operon composed of three open reading frames: fbpA, encoding for FbpA; fbpB, that codifies a cytoplasmic permease, and fbpC, that contains the information for a nucleotide binding protein. These proteins would form an iron transport system through the periplasmic space. FbpA is highly antigenic in mice when injected in purified form, shows intraspecies and interspecies antigenic homogenicity, and specific anti-FbpA antibodies are fully cross-reactive; nevertheless, the in vivo induction of anti-FbpA antibodies in man is still polemical. Recent studies reveal that the purified FbpA induces a fair response of bactericidal antibodies in mice.

GR-891: a novel 5-fluorouracil acyclonucleoside prodrug for differentiation therapy in rhabdomyosarcoma cells

Differentiation therapy provides an alternative treatment of cancer that overcomes the undesirable effects of classical chemotherapy, i.e. cytotoxicity and resistance to drugs. This new approach to cancer therapy focuses on the development of specific agents designed to selectively engage the process of terminal differentiation, leading to the elimination of tumorigenic cells and recovery of normal cell homeostasis. A series of new anti-cancer pyrimidine acyclonucleoside-like compounds were designed and synthesized by structural modifications of 5-fluorouracil, a drug which causes considerable cell toxicity and morbidity, and we evaluated their applicability for differentiation therapy in human rhabdomyosarcoma cells. We tested the pyrimidine derivative GR-891, (RS)-1-[[3-(2-hydroxyethoxy)-1-isopropoxy]propyl]-5-fluorouracil, an active drug which shows low toxicity in vivo and releases acrolein which is an aldehyde with anti-tumour activity. Both GR-891 and 5-fluorouracil caused time- and dose-dependent growth inhibition in vitro; however, GR-891 showed no cytotoxicity at low doses (22.5 micromol l(-1) and 45 micromol l(-1)) and induced terminal myogenic differentiation in RD cells (a rhabdomyosarcoma cell line) treated for 6 days. Changes in morphological features and in protein organization indicated re-entry in the pathway of muscular maturation. Moreover, GR-891 increased adhesion capability mediated by the expression of fibronectin, and did not induce overexpression of P-glycoprotein, the mdr1 gene product, implicated in multidrug resistance. New acyclonucleoside-like compounds such as GR-891 have important potential advantages over 5-fluorouracil because of their lower toxicity and their ability to induce myogenic differentiation in rhabdomyosarcoma cells. Our results suggest that this drug may be useful for differentiation therapy in this type of tumour.

Effect of adjuvants in the isotypes and bactericidal activity of antibodies against the transferrin-binding proteins of Neisseria meningitidis

Twenty-eight Neisseria meningitidis strains of different serogroups, serotypes, and TbpB isotypes were used to test the effect of five adjuvant formulations on the immune response to the meningococcal transferrin-binding proteins (Tbps) in mice. Levels of anti-Tbps antibodies were relatively low when purified TbpA-TbpB complexes were used for immunization, those obtained with the RAS adjuvant being the highest, and the isotype distribution reveals a prevalence of the non-bactericidal IgG1. Specific anti-Tbps antibody levels were five to 125 times higher immunizing with whole outer membrane vesicles, with bactericidal isotypes prevailing, which suggests that presentation of these antigens in their natural conformation is crucial to elicit a good response. Nevertheless, bactericidal activity did not correlate with these characteristics, confirming that it must be also influenced by other factors, and direct evaluation of the killing ability is necessary to draw conclusions about the efficacy of antigens or adjuvants in vaccine design.

Analysis of TbpA and TbpB functionality in defective mutants of Neisseria meningitidis

Iron uptake analysis suggested that the Neisseria meningitidis transferrin (Tf) binding proteins, TbpA and TbpB, form only one type of receptor complex. Mutants defective in the synthesis of either TbpA or TbpB, but not defective in both proteins, can bind Tf, suggesting that both proteins are surface exposed and function in Tf binding. Also, iron uptake from Tf into the meningococci did not require the presence of both Tbps. The TbpB-defective mutant incorporated c. 37% of the iron taken up by the wild-type strain, but this was insufficient for bacterial growth. The TbpA-defective mutant incorporated c. 50% of the iron taken up by the wild-type strain and was able to grow with Tf as the only iron source. Mouse antibodies specific for TbpA were able to block c. 70% of the iron uptake from Tf in the wild-type strain, whereas they blocked only 22% of iron uptake in the TbpB-defective mutant and did not block uptake in the TbpA-defective strain. These results emphasise that TbpA should be considered in future vaccine trials in which iron-restricted proteins are to be included in the vaccine formulation.

Cooperation between the components of the meningococcal transferrin receptor, TbpA and TbpB, in the uptake of transferrin iron by the 37-kDa ferric-binding protein (FbpA)

Meningococcal TbpAB complexes TbpA, TbpB and FbpA were purified and used to study their role in the uptake of iron from transferrin to FbpA. Purification was achieved by affinity chromatography techniques, yielding homogeneous, non-denatured and functional material. TbpA could not be separated from TbpB and had to be purified from a TbpB-defective mutant strain. FbpA was able to bind iron from transferrin only when TbpAB complexes, TbpA and/or TbpB, were also present during the interaction. The highest uptake efficiences were obtained with TbpAB complexes or TbpA/TbpB mixtures. We conclude that the TbpA and TbpB molecules form true functional transferrin receptors, that FbpA is able to take iron directly from transferrin when in the presence of the components of the receptor, and that both Tbps are necessary for an optimal operation of the uptake system.

Anticipating rotavirus vaccines: review of epidemiologic studies of rotavirus diarrhea in Argentina

Rotavirus is the most common cause of severe diarrhea in children worldwide, and vaccines currently being field-tested could be available for childhood immunization in several years. To assess the rotavirus disease burden in Argentina and the value of future national surveillance for the disease, we reviewed available data on rotavirus detections reported by published and unpublished studies conducted in nine Argentine cities and by a multicenter study. Data from these studies indicated that rotavirus was detected in 20% of 5,226 specimens (within a range of 6% to 54% for different studies) from children hospitalized for diarrhea and in 9% of 6,587 specimens (within a range of 5% to 22% for different studies) from children who were outpatients, members of mixed populations (hospitalized patients and outpatients), or survey subjects in community-based studies. The hospital data showed that while rotavirus was detected throughout the year, a peak occurred during the winter months (May-July) when up to half of the children with diarrhea were found positive for rotavirus. Attempted serotyping of 294 rotavirus-positive specimens for G-protein by three laboratories was successful in 230 cases (78%); the resulting data indicated that serotype G1 was the most common (being present in 60% of the successfully serotyped specimens), followed by G2 (in 20%), G4 (in 14%), and G3 (in 5%). Based on national data for Argentina, we estimate that in 1991 there were roughly 84,500 rotavirus-associated outpatient visits (1 for every 8 births) and 21,000 hospitalizations averaging 4 days in length (1 for every 31 births), all of which entailed direct medical costs estimated at US$ 27.7 million. These preliminary data show that the rotavirus disease burden in Argentine children is extensive and could be decreased by a safe and effective vaccine. Further surveillance is needed to improve our understanding of the epidemiology and distribution of rotavirus strains in Argentina, to more accurately assess the cost-effectiveness of a rotavirus vaccine program, and to indicate what methods might best be used to monitor such a program's impact.

Pharmacokinetics, biodistribution and dosimetry of 99mTc-labeled anti-human epidermal growth factor receptor humanized monoclonal antibody R3 in rats

The pharmacokinetics, biodistribution and dosimetry of 99mTc-labeled anti-human epidermal growth factor receptor (anti-hEGF-r) humanized monoclonal antibody (MAb) R3 was investigated following intravenous injection in normal Wistar rats. Serum disappearance curves were best fit by a two-compartment model having a mean distribution half-life (t 1/2alpha) of 0.250 h and a mean elimination (t 1/2beta) of 13.89 h. Among the various organs, a little accumulation of the radiolabeled antibody was found only in kidneys. Biodistribution and dosimetry studies in humans were performed by extrapolation of the animal data to humans. Absorbed dose to normal organs and the remainder of the whole body were estimated using the medical internal radiation dose formula, and dose contributions from radioactivity in transit through the gastrointestinal tract were estimated using a compartment model. Extrapolated values of radiation absorbed dose to normal organs in rads per millicurie administered were whole body, 0.0085; lower large intestine wall, 0.0898; small intestine, 0.0530; upper large intestine wall, 0.0731; and kidneys, 0.0455. The effective dose equivalent predicted was 0.0162 rem/mCi and the effective dose was found to be 0.015 rem/mCi. On the basis of the pharmacokinetics, biodistribution and internal radiation dosimetry information obtained in this study, a diagnostic phase I clinical trial with 99mTc-labeled humanized MAb R3 conjugate in patients should be supported.

Bactericidal activity of antibodies elicited against the Neisseria meningitidis 37-kDa ferric binding protein (FbpA) with different adjuvants

The 37-kDa ferric binding protein, FbpA, from three Neisseria meningitidis strains was purified to homogeneity with iron-affinity chromatography and used for immunisation of mice employing four different adjuvants: aluminium hydroxide, Freund's, the saponin Quil-A, and a Ribi adjuvant system (RAS). Controls immunised without adjuvant were also included. All sera obtained were monospecific for the meningococcal FbpA, with antibody titres higher when RAS and Quil-A were used (256), PBS resulting in titres similar to those of Freund's (64), and, surprisingly, with no antibodies elicited when aluminium hydroxide, the only approved adjuvant for use in humans, was used. All anti-FbpA sera bound to intact meningococcal cells, showing a complete cross-reactivity, but the bactericidal activity of anti-FbpA antibodies, demonstrated for the first time in this work, was low (32% of killing with the homologous strain), and the analysis of immunoglobulin isotypes showed that the non-bactericidal IgG1 was predominant. The results confirm that the FbpA is surface-exposed, antigenic, and able to elicit bactericidal antibodies, although, in the conditions and with the adjuvants tested, killing efficacy was low and cross-killing was very variable, not supporting the inclusion of this protein in vaccine formulations. Nevertheless, given the high conservation of the FbpA in the genus Neisseria, its surface exposure and its antigenicity, studies on immunisation with peptides corresponding to the exposed epitopes and/or new adjuvant systems could improve the bactericidal response to this protein, making it suitable for vaccine development.

Urothelial transitional cell carcinoma with endophytic growth patterns: a discussion of patterns of invasion and problems associated with assessment of invasion in 18 cases

Most papillary transitional cell carcinomas (TCC) are characterized architecturally by an exophytic growth of fingerlike papillae, but some exhibit a prominent endophytic growth pattern resulting in considerable difficulty in assessing invasion. We report on 18 cases of TCC (17 urinary bladder, one pelvicalyceal system) in which endophytic growth was evident either as interanastomosing cords and columns of urothelium, often with a striking resemblance to inverted papilloma (inverted papilloma-like pattern), or as broad, pushing bulbous invaginations into the lamina propria (broad-front pattern). The mean age of the patients was 68 years (range, 32-94 years), with a male preponderance (3.5:1). In four cases, the endophytic pattern was exclusively inverted papilloma-like, 10 cases had only the broad-front pattern, and four cases showed both patterns. Exophytic papillary TCC of the usual type was present in all but two cases, varying from focal (five cases) to moderate (five cases) to extensive (six cases). In spite of the extensive incursion into the lamina propria resulting from the inverted growth, only nine cases (50%) had unequivocal destructive invasion (lamina propria invasion, eight cases; muscularis propria invasion, one case). Follow-up data, available in 14 cases (1-48 months; mean, 15.5 months), revealed one patient alive with disease, 11 patients with no evidence of disease, and two patients dead of other causes. The limited follow-up does not permit evaluation of the impact of the endophytic patterns on outcome. Because the phenomenon of endophytic growth in TCC has received little attention, we present detailed morphologic descriptions of our cases and review the problems associated with assessment of invasion and the different patterns of invasion by TCC.

Diheterocyclanes as synthons for the preparation of novel series of nucleoside and acyclonucleoside analogues

Convenient synthesis of 1-[[3-(2-hydroxyethylhetero)-1-alkoxy]alkyl]-5-fluorouracils 3-8 was accomplished via the use of tin (IV) chloride, capable of a 1,4-chelation on alkoxy-1,4-diheteroepanes. Increasing the reaction time led to 5-FU seven-membered nucleoside analogues which could be considered as upper isosteres of the effective antitumour agent Ftorafur. Using 1-[[3-(2-hydroxyethoxy)-1-alkoxy]propyl]-5-fluorouracil as a parent drug, several chemical modifications on the acyclic moiety were made with the aim of obtaining new compounds showing significant antiproliferative activity in rhabdomyosarcoma (RD) cells. 14 treatment in vitro caused time- and dose-dependent growth inhibition on RD cells. Interestingly, when they were treated with doses of 35 microM and 140 microM of 14 for 6 days, they showed morphological and phetotypic differentiation with increased expression of desmin, alpha-actinin and tropomyosin. We suggest a potential role for differentiation therapy as a therapeutic approach to the treatment of rhabdomyosarcoma.

Blocking of iron uptake by monoclonal antibodies specific for the Neisseria meningitidis transferrin-binding protein 2

The existence of epitopes common to different strains in the Neisseria meningitidis transferrin (Tf)-binding protein 2 (TBP2), combined with the ability of polyclonal anti-TBP2 antibodies to inhibit Tf binding and block iron uptake in this species, led to this study on the effect of anti-TBP1+2 monoclonal antibodies (MAbs) to determine the presence of epitopes inside the Tf-binding region. All MAbs used reacted exclusively with the homologous strain when tested by dot-blots of outer membrane vesicles, with the reaction being specific for TBP2 after SDS-PAGE and electroblotting. In contrast, ELISA and iron-uptake blocking assays were also positive with heterologous strains belonging to Rokbi's group II (high mol.wt TBP2). The results confirmed the two group classification proposed by Rokbi and, in contrast to other studies, indicated the existence of epitopes in the Tf-binding region that are common only to strains of Rokbi's group II. These epitopes may become denatured after drying for dot-blot assays or after SDS-PAGE and electroblotting.

Antigenicity, cross-reactivity and surface exposure of the Neisseria meningitidis 37 kDa protein (Fbp)

The 37 kDa iron-repressible protein, Fbp, was purified from two Neisseria meningitidis strains by metal-affinity chromatography and used to obtain mouse monospecific polyclonal immune sera. Dot-blot, immunoblotting and whole cell ELISA results demonstrate that the Fbp is present in all 16 N. meningitidis and four commensal Neisseria species tested, is highly antigenic in mouse when injected in pure form, and shows intra- and inter-species antigenic homogeneity, anti-Fbp antibodies being fully cross-reactive using the techniques mentioned. We also found that Fbp molecules (or parts of them) are surface exposed, in disagreement with the proposed exclusively periplasmic localization, although anti-Fbp antibodies seem unable to block iron uptake or to induce complement-mediated killing of the meningococci. Taken along with the high immunogenicity of the purified protein and the complete cross-reactivity of the antibodies elicited, this suggests that the protective effect of the purified Fbp must be further studied to evaluate its inclusion in future vaccine trials.

Blocking of iron uptake from transferrin by antibodies against the transferrin binding proteins in Neisseria meningitidis

Neisseria meningitidis, when cultured in iron-restricted environments, synthesises new outer-membrane proteins, many of which are necessary for their survival and growth. Some of these proteins e.g. transferrin-binding proteins 1 and 2 (Tbp1 and Tbp2), are required for the acquisition of iron from transferrin and are examples of important iron-regulated meningococcal surface antigens which are not expressed after growth in common laboratory media. The antigenicity and antigenic heterogeneity of these proteins have been extensively studied, and the bactericidal activity of antibodies directed to them have been studied. In this work we analysed the ability of such antibodies to inhibit transferrin binding and to block iron uptake from human transferrin. Antisera from mice immunized with either meningococcal outer membrane vesicles, purified Tbp1/2 complexes, or purified Tbp2, were incorporated in radiolabeled-iron uptake assays. Uptake was blocked by more than 80% in the homologous strains, but blocked much less efficiently in some heterologous strains, correlating well with inhibition of transferrin binding and with an inhibitory effect on bacterial growth. Inhibition of iron uptake from citrate was unaffected which suggests that this effect is due to antibodies against the components of the transferrin binding system, specially Tbp2. Our results support the importance of these proteins and their suitability to be considered in the development of effective vaccines against serogroup B meningococci.

[Aortic prosthetic endocarditis and periprosthetic abscess caused by Staphylococcus aureus]

Prosthetic endocarditis with annular abscess formation is a severe complication of cardiac valve replacement fortunately uncommon, though highly lethal. Increasing surgical experience and the high mortality with medical management have led to a widespread recommendation for early prosthetic replacement. We report a case of a 49 year old man with infective endocarditis due to Staphylococcus aureus in aortic ascendens prosthetic and aortic valve prosthetic complicated with periaortic abscess which was as successful treatment by drain of abscess without prosthetic replacement.

Anticancer pyrimidine acyclonucleosides

Several acyclonucleosides have been synthesized. Series 8 could liberate 5-FU and acrolein selectively in the tumour tissue whilst 9 only discharge 5-FU. The conformational analysis of 8 and 9 has been carried out by means of Molecular Mechanics, using the MM2 force field. It was observed that the open chain linked to the N-1 of the 5-FU moiety mimics the conformational structure of the sugar of desoxyuridine. Biological assays have been carried out in vitro on tumour growth in Ehrlich ascitic cells with the consequent decrease of 35% in the cellular mitosis. IC50 showed values between 3-45 microM for series 8 whilst series 9 were less active than 5-FU. Compared with that of 5-FU the acute and chronic toxicity is considerably decreased.

[Non-invasive diagnosis of rejection in heart transplant: usefulness of Doppler echocardiography]

Cardiac transplantation is a valid therapeutic option for advanced chronic heart failure, with a one year survival of 60-80%. Although the introduction of cyclosporine has markedly improved survival in heart transplant recipients, early detection of cardiac allograft rejection remains the major problem to be solved. At present, the diagnosis of cardiac rejection has been based on the results of endomyocardial biopsy, which remains actually as the gold standard for rejection surveillance. However, ideally the detection of cardiac rejection should be noninvasive to allow frequent follow-up of the patients. Several attempts have been made to find a noninvasive alternative to replace endomyocardial biopsy, doppler-echocardiography being the most promising technique. A review of current noninvasive methods for graft rejection detection will be discussed emphasising the importance of doppler-echocardiography.

[Changes in diastolic function in heart rejection: role of Doppler echocardiography]

In acute cardiac rejection, left ventricular diastolic function is altered. To study these abnormalities and their utility in cardiac allograft rejection, we studied 56 cardiac transplant recipients. All patients were assessed with endomyocardial biopsy and Doppler echocardiography done in the same day. A total of 163 Doppler studies were recollected. Cardiac transplant recipients were excluded during the early 6 weeks postoperative period. Totally, 100 biopsies were normal, 48 positive for mild rejection (Billingham Gde I-II) and 15 positive for moderate or severe rejection (Billingham Gde III-IV). Compared to negative biopsies, during acute rejection left ventricular wald thickness significantly increased (p < 0.05); isovolumic relaxation period and pressure half-time significantly decreased (p < 0.05, p < 0.001 respectively). Nevertheless, increase in peak early mitral flow velocity was only significantly associated with severe rejection (p < 0.001). Correlating only progressive shortening of isovolumic relaxation period parameter in the diagnosis of graft rejection, we forward a high sensibility (85%) and low specificity (57%). Thus, Doppler echocardiographic evaluation of left ventricular diastolic function provides a non-invasive tool for early detection of acute rejection monitoring after the early postoperative period.

[Comparative study of two lipid emulsions in patients receiving total parenteral nutrition]

INTRODUCTION

the use of lipid emulsions together with glucose as a calorie source in parenteral nutrition has undisputed advantages. Their isotony and high calorie content mean they are essential for peripheric parenteral nutrition and in parenteral nutrition of long duration they are important in providing essential fatty acids.

OBJECTIVE

to determine the constant of elimination of two commercial lipid emulsions with similar compositions, and evaluate whether significant differences exist between them. MATERIAL, METHODS AND PATIENTS: 20 candidates for total parenteral nutrition were studied over a period of at least ten days. These patients showed no severe stress, sepsis or IRA. The patients received total parenteral nutrition for at least 3 days prior to commencing the study; 12 hours after initiation, total parenteral nutrition was administered, without lipids. Afterwards, one of the emulsions studied was infused centrally (in Y with the parenteral nutrition) at a rate of 0.15 g/kg/hour for 3 hours, 24 hours later, the other emulsion was infused under the same conditions. Commencing with one or the other was done at random, and both at 10%. Blood samples were taken at the following times:--10.0 (end of the infusion of the emulsion), 10, 30, 60 and 90 minutes, and the following parameters studied: total cholesterol (col), triglycerides (tg) and phospholipids (pl); tg, col ad pl of the VLDL, HDL and LDL, free fatty acids and lipoprotein lipase. The analytical methods employed were: ultracentrifugation with compressed air and precipitation with PEG-6000.

RESULTS

significant differences were observed in the constant of elimination of total tg (2.54 +/- 0.73 in emulsion A compared to 2.8 +/- 0.66 in B), in the Kd of the VLDL tg (1.65 +/- 0.86 in A compared to 1.99 +/- 0.77 in B) and in the Kd of the VLDL P1 (0.98 +/- 0.53 in the case of A compared to 1.1 +/- 0.43 in emulsion B), no significant differences were found in the other parameters studied. The Student T was applied, and no lipase lipoprotein activity was observed.

DISCUSSION

the differences found may perhaps be explained by the action of the emulgent on the intravascular metabolism of the fats. Although in both cases this is egg lecithin, the composition of this has not been studied in depth. Emulsion A = Intralipid (n. reg). Emulsion B = Tutolipid (n. reg.).

[Current use of anti-hemostatics in ischemic cardiopathy]

Antihemostatic drugs are widely used in the treatment and prevention of ischemic heart disease. Fibrinolytic agents are prescribed in the early phase of acute myocardial infarction, to reduce its size and improve survival. Their use in unstable angina is still controversial. Anticoagulants have substantial benefit in myocardial infarction, unstable angina and primary prevention of coronary disease. Finally, antiplatelet agents are used in stable and unstable angina, myocardial infarction and high risk patients.

Epidemiology of rotavirus infection and gastroenteritis in prospectively monitored Argentine families with young children

A prospective study was carried out in 49 families of newborns in Avellaneda District, Argentina, recruited when the mother was in the last trimester of pregnancy and followed until the newborn was aged two years, to study the epidemiology of rotavirus infection under natural conditions. Weekly surveillance of all family members for diarrhea and rotavirus-related diarrhea was carried out from May 1983 to July 1986. Serum samples were also collected every six months to study the incidence of rotavirus infection in all family members. The peak of diarrhea incidence was observed in children aged less than two years (2.1 cases per person-year). Rotavirus infection was a common rather than a sporadic phenomenon (0.63 cases per person-year, on average) in all age groups, and at least 61% of rotavirus infections were reinfections. In contrast, the peak of rotavirus infection in seronegative persons (0.58 cases per person-year) and the peak of rotavirus-related diarrhea incidence (0.25 cases per person-year) were found during the first year of life. These results showed that infants aged less than one year are the most appropriate candidates for a rotavirus vaccine in the Avellaneda population. However, improvements in sanitary conditions and personal hygiene and education of the high-risk population should be considered the primary means of reducing infectious diarrhea in Argentina.

Apolipoprotein E phenotypes, lipoprotein composition, and xanthelasmas

The different types of serum lipoproteins, including apolipoprotein E phenotypes, were measured in 50 patients with xanthelasma. Half of them were found to be hyperlipemic. The normolipemic and hyperlipemic groups with xanthelasma were compared with two control groups (one a group of normolipemic patients and another a group of hyperlipemic patients without xanthelasma) selected as homogeneously as possible with regard to age, sex, degree of obesity, and hyperlipemic phenotype. The only significant differences found among the groups, regardless of the presence of hyperlipemia, were the increased levels of total and high-density lipoprotein phospholipids, and lower levels of apolipoprotein B, found in the group with xanthelasmas. The distribution of apolipoprotein E phenotypes was the same in both groups, with slight differences between the normolipemic and hyperlipemic groups. Patients with xanthelasmas showed slight deviations in the metabolism of lipoproteins that require further clarification.