Study of the antibody response against Mycobacterium tuberculosis antigens in Warao Amerindian children in Venezuela

This study was aimed at investigating alternate methods for serodiagnosis of tuberculosis (TB), which are needed because bacteriologic diagnosis of childhood TB is difficult. A selection of 80 serum and saliva samples were tested from Warao indigenous children under 15 years of age; 34 high TB suspects (28 positive and 6 negative for the tuberculin skin test, TST) and 46 healthy contact children (32 positive and 14 negative for the TST). Several enzyme-linked immunosorbent assay (ELISA) serological tests were developed to test for Mycobacterium tuberculosis-specific antibodies, including serum IgA, IgG, IgE, and secretory IgA (sIgA) in saliva against 3 specific antigens (PPD, HSP60, 38 kDa). Of these, 2 antigens, PPD and 38 kDa, showed significantly higher reactivity. The sensitivity and specificity of these tests for diagnosis remained limited, between 26.5% and 38.2%, and 77.4% and 97%, respectively. Of all the samples studied and combinations realized between all isotypes and antigens combined with 3 isotypes (anti-PPD IgG, IgE, and anti-38kDa sIgA) managed to detect the largest number of patients, showing an improved sensitivity level of 64.7%, although specificity levels dropped to 81.8%. These results were compared with the Omega diagnostics commercial kit results. The commercial kits showed significantly lower reactivity (sensitivity of 20% and 13.33% to Myco G and Complex Plus, respectively) and a specificity of 100%. This study shows that in indigenous populations of Venezuela, where invasive procedures cannot be used to select samples but evaluation with a chest X-ray for radiological studies is available, the combination of 3 specific isotypes may be a useful tool to increase diagnostic accuracy with pulmonary TB in this population, when used together with clinical and epidemiological criteria.

[Metabolic imaging by positron emission tomography using [18F] fluorodeoxiglucose in developmental disorders]

INTRODUCTION

Developmental disorders are a common pathological condition in Neuropaediatrics and do not usually present characteristic anatomical alterations in the different neuroanatomical imaging tests that can be employed, such as computerised axial tomography or magnetic resonance (MR). Positron emission tomography (PET) using [18F] fluorodeoxiglucose (PET FDG), one of the battery of imaging tests currently available, enables us to obtain data about brain activity in a non invasive manner.

PATIENTS AND METHODS

A group of 39 patients with developmental disorders from the Hospital del Mar was analysed. They were submitted to PET FDG brain metabolism tests and in some cases hybrid PET MR images were also obtained; findings were then correlated against the clinical progression of the patients.

RESULTS AND CONCLUSIONS

The alterations that were observed showed predominantly bilateral thalamic, mesial temporal and orbital frontal hypometabolism. This alteration of the limbic system, which has no correlation with anatomical damage, can be a predictor of the clinical progression and of the confirmation of the presence of alterations in the brain functions in this type of patients.

ECHINOSTOMA LUISREYI N. SP. (PLATYHELMINTHES: DIGENEA) BY LIGHT AND SCANNING ELECTRON MICROSCOPY

The entire life cycle of the Brazilian Echinostoma luisreyi n. sp., of the 37-collar spine E. revolutum group, has been observed under experimental conditions. The snail Physa marmorata serves as its first natural intermediate host. This species and the planorbid Biomplalaria glabrata act as experimental second intermediate hosts. The worm recovery rate was 51.3 and 0.6% for mice and hamsters, respectively, but the infection did not develop in the quail Coturnix coturnix. The natural vertebrate host is not known. The most important morphological character of the new species separating it from the other Echinostoma species studied is the oral corner spines that increase in size from the latero-oral to the ventro-oral regions. The ratio of the sizes of the smaller oral spines and the larger aboral ones was 1.7:1.0. Also, the excretory pore is radially wrinkled and dorsally subterminal. Images obtained by scanning electron microscopy confirmed the characters that differentiate the new species and the most closely related species.

Comparison of diagnostic techniques for porcine proliferative enteropathy (Lawsonia intracellularis infection)

In studying the post-mortem diagnosis of porcine proliferative enteropathy (PPE) a "double-blind" study was performed on 77 apparently healthy "finisher" pigs at the time of slaughter, to compare the results of a polymerase chain reaction (PCR) technique with those of (1) an indirect immunofluorescence assay (IFA), (2) examination for gross proliferative lesions at slaughter, (3) histopathological study of sections stained with haematoxylin and eosin (HE), and (4) Warthin-Starry (WS) silver staining for intracellular bacteria. The IFA, with a sensitivity of 89% and a specificity of 97% (positive "likelihood ratio"=30) and an agreement of 82% with PCR, is suggested as an alternative to the PCR in the post-mortem diagnosis of PPE. Histopathological examination was shown to be of little use as a principal diagnostic method, although it appeared to be effective in diagnosing infection by Lawsonia intracellularis in cases with proliferative-type lesions (positive likelihood ratio=29.6). Finally, the values obtained from an examination of gross lesions (k=0.075; positive likelihood ratio of 1.3) and WS staining (k=0.42; positive likelihood ratio of 5.3) demonstrated the lack of validity of these tests for the diagnosis of L. intracellularis infection.

[Nutritional effect of bariatric surgery with Scopinaro operation. Analysis of 40 cases]

OBJECTIVES

To analyze the influence of bariatric surgery over nutritional status in patients with morbid obesity after 1 year of following. To know the influence of specific factors as age, sex and common channel's length.

DESIGN

Retrospective study from 1998-2001.

SUBJECT

All patients suffering from morbid obesity that had been operated during this period of time, 40 subjects: 28 women and 12 men with a mean age of 38 +/- 12 years old. Were studied.

METHODS

We analyzed the variations of weight and other anthropometric measures, biochemical parameters and the micronutrient (vitamins A, D, E, B12, folate, C, zinc, Calcium, Magnesium) status during 1 year of following after surgery.

RESULTS

Percentage weight loss was 29.7 +/- 2.9% without sex differences. A significant (p < 0.005) descent of serum cholesterol, triglycerides, and uric acid level as well as liver function markers was observed. All the hyperglycemic disturbances were reverted. 97% and 48% of the patients developed hypovitaminosis A and D respectively, that was correlated to steatorrhea. Vitamin E deficiency was found in 72% of the patients, and zinc deficiency in 68%

CONCLUSIONS

Our expected weight loss 1 year after bariatric surgery is 30%, irrespective of sex and age. This loss is accompanied by a significant improvement in metabolic parameters, but the high prevalence of micronutrients deficiency that was found makes an early supplementation and close follow-in of these patients very advisable.

Changes on Schistosoma mansoni (Digenea: Schistosomatidae) worm load in Nectomys squamipes (Rodentia: Sigmodontinae) concurrently infected with Echinostoma paraensei (Digenea: Echinostomatidae)

The water rat, Nectomys squamipes, closely involved in schistosomiasis transmission in Brazil, has been found naturally infected simultaneously by Schistosoma mansoni and Echinostoma paraensei. Laboratory experiments were conducted to verify parasitic interaction in concurrent infection. It was replicated four times with a total of 42 water rats and essayed two times with 90 mice pre-infected with E. paraensei. Rodents were divided into three groups in each replication. A wild strain recently isolated from Sumidouro, RJ, and a laboratory strain of S. mansoni from Belo Horizonte (BH) was used. Rats infected with E. paraensei were challenged 4 weeks later with S. mansoni and mice 2 or 6 weeks after the infection with S. mansoni. Necropsy took place 8 weeks following S. mansoni infection. The N. squamipes treatment groups challenged with S. mansoni RJ strain showed a significant decrease (80 and 65%) in the S. mansoni parasite load when compared with their respective control groups. There was a significant change or no change in the hosts challenged with the BH strain. The persistence time of E. paraensei within host was extended in relation to control groups, with a consequent enhancement of the number of recovered worm. An E. paraensei strain-specific influence on S. mansoni parasitism is reported. This paper presents some experimental data about this interaction in N. squamipes and Mus musculus.

Endocrine regulation of gonadotropin glycosylation

The pituitary gonadotropins--luteinizing hormone and follicle-stimulating hormone--as well as the placental choriogonadotropin belong to the family of glycoprotein hormones. These structurally related hormones, which regulate several major reproductive functions of the body, are heterodimers consisting of a common alpha-subunit noncovalently bound to a beta-subunit. The N- and O-linked oligosaccharide chains of these gonadotropins play an important role in intracellular folding, assembly, secretion, metabolic clearance, and biological activity of the hormone. Gonadotropin glycosylation is a highly complex process; within the gonadotropes it is modulated by a variety of extrapituitary factors of hypothalamic and gonadal origin. In particular, estrogens and androgens appear to regulate terminal sialylation and/or sulfation of the oligosaccharide attachments and hence some functional properties of the gonadotropin molecule determined by these residues, i.e., metabolic clearance and in vivo biopotency. Through these extrapituitary inputs, the anterior pituitary may not only regulate the quantity but also the quality of the gonadotropin signal delivered to the gonads in a given physiologic or pathologic condition.

Description of the adult worms of a new Brazilian isolate of Echinostoma paraensei (Platyhelminthes:Digenea) from its natural vertebrate host Nectomys squamipes by light and scanning electron microscopy and molecular analysis

Echinostoma paraensei Lie and Basch, 1967 (Echinostomatidae:Platyhelminthes), a 37 collar spine echinostome of the "revolutum group", has been used extensively as a model organism to study the interactions of digenetic trematodes with both their snail and vertebrate hosts. This worm was first isolated from the snail Biomphalaria glabrata from Belo Horizonte (BH isolate), Minas Gerais State, Brazil, by Lie and Basch [J Parasitol (1967) 53:1192-1199]. The natural definitive host for the BH isolate was never determined, and it has been maintained in the laboratory since 1967 in B. glabrata and hamsters. In this study, using light and scanning electron microscopy and molecular analysis, we describe an echinostome recently obtained from its natural vertebrate host, the wild rodent Nectomys squamipes (Rodentia: Sigmodontinae) from Sumidouro, Rio de Janeiro State, Brazil (RJ isolate). This echinostome was also compared to the laboratory-maintained BH isolate of E. paraensei. We observed that adult worms of both BH and RJ isolates could be differentiated from other echinostome species by the relatively small size of the dorsal collar spines relative to lateral and corner collar spines. SEM confirmed the similarity of this morphological character between the two isolates. As additional diagnostic features, the tegumentary spines are scale-like and the region between the genital pore and the acetabulum lacks scales. There is a folded protuberance with a pore just posterior to the genital pore. The tegument of the acetabulum is unspined and radially wrinkled, and there are numerous randomly distributed small, domed, ciliated papillae. The sequences of the internal transcribed spacers of the nuclear rDNA complex of the RJ and BH isolates are identical. Together these shared features provide strong evidence that both isolates are the same and can be referred to as E. paraensei. In conclusion, we have identified, for the first time, one of the natural definitive hosts for E. paraensei, the rodent N. squamipes, and have extended the known geographical distribution of this species to include Sumidouro in Rio de Janeiro State, Brazil.

Biological aspects of a new isolate of Echinostoma paraensei (Trematoda: Echinostomatidae): susceptibility of sympatric snails and the natural vertebrate host

A new isolate of Echinostoma paraensei (Lie & Basch, 1967) was obtained from a natural vertebrate host, the water rat Nectomys squamipes. Relationships with sympatric snails, Biomphalaria glabrata; Physa marmorata and Lymnaea columella, as well as allopatric snails and the definitive hosts N. squamipes, Mus musculus, Rattus norvegicus, Mesocricetus auratus and birds were investigated. E. paraensei developed in all sympatric snail species following exposure to one or five miracidia. P. marmorata showed the highest infection rate (34% and 36%) followed by L. columella (18% and 24%) and B. glabrata (8% and 28%), respectively. Mortality was elevated in the patent period, with L. columella having the highest values. B. glabrata, P. marmorata, and L. columella did not differ in relation to cercarial encystment, and metacercariae from each species were able to infect N. squamipes with similar worm burdens. Recovered adult worms were found in clusters from the first to third sections of the small intestine. Miracidia of E. paraensei hatched after 10 days incubation in darkness in dechlorinated water at 28+/-1 micro C. Miracidia began to hatch 1 h after exposure to incandescent light.

Clinical Impact of 18F-FDG-PET in the Suspicion of Recurrent Ovarian Carcinoma Based on Elevated Tumor Marker Serum Levels

Purpose: To retrospectively evaluate the contribution of 18F-fluorodeoxy-glucose-positron emission tomography (FDG-PET) to the diagnosis and clinical management of patients who were suspected of recurrent ovarian carcinoma, based on elevated tumor markers levels with normal or equivocal computed tomography (CT) or nuclear magnetic resonance (NMR).Procedures: 20 patients with these characteristics underwent FDG-PET. PET findings were confirmed in 14, in 7 by surgery, and in the other 7 by clinical course.Results: Recurrence was confirmed in 12 patients, all with FDG-PET positive. In other 2, recurrence was rule out and in 1, FDG-PET was negative. FDG-PET accuracy was 93% with 4 surgeries avoided and guided other 6.Conclusions: FDG-PET is an useful technique for detecting recurrent ovarian carcinoma suspected by elevated tumor markers levels and normal or equivocal results in the morphologic imaging techniques and has an important clinical impact on the management of these patients.

[Evaluation of the tuberculin reaction in health occupation students]

A cross-sectional study was done at the University of Antioquia, MedellIn, Colombia, to evaluate the response to a tuberculin skin test among students in undergraduate health programs (medicine, odontology, nursing, and bacteriology) as compared to undergraduate students in nonhealth programs. The study included students from the beginning, middle, and end of the university's academic programs. The sample of 490 students included 273 from health programs and 217 from nonhealth programs. Participants were randomly selected using lists provided by the university registrar, for the second semester of 1998. The presence of a BCG vaccination scar was determined, and all the participants were also questioned about TB-related risk factors. Tuberculin skin test reactivity was evaluated by the size of induration 72 hours after intradermal injection of two tuberculin units of purified protein derivative RT 23. There were no differences in tuberculin reactivity between students from the health programs and from the nonhealth programs, irrespective of the academic level. However, there was a significantly higher proportion of positive skin tests among students with a BCG scar. These results suggest that undergraduate health students do not have extensive contact with TB patients or with clinical samples from such patients. Nevertheless, the results do not rule out TB as an occupational risk for health personnel.

[Role of the positron emission tomography (PET) in suspected tumor recurrence when there is increased serum tumor markers]

PURPOSE

Evaluate the usefulness of Positron Emission Tomography with 18F-Fluorodeoxyglucose (FDG-PET) to detect lesions when tumor recurrences are suspected due to the progressive increase of tumor markers and the study of their extension with negative or non-conclusive morphostructural diagnostic techniques.

MATERIAL AND METHODS

Whole body FDG-PET was per-formed in 72 patients with different cancer diseases, 23 of whom had breast, 18 colorectal, 15 thyroid, 6 lung, 3 ovarian cancer and 7 had other types of cancers. Tumoral recurrence was suspected in all of the cases due to the progressive marker increase and negative or non-conclusive conventional studies.

RESULTS

FDG-PET detected lesions in 85% patients, 33% of which were confirmed by the end of the study. In 40% of all cases, therapeutics measures were applied, 14% of which consisted in surgery with intention to cure. Sensitivity, specificity and accuracy were 96.4%, 75.6% and 93.9% respectively.

CONCLUSIONS

Whole body FDG-PET is an accurate procedure in diagnosis of recurrent tumoral disease in patients with rising tumoral marker levels and with negative conventional morphostructural extension studies, and can make it possible to change the therapeutic approach in some cases.

17. Utility of Metabolic Imaging in Oral Squamous Cell Carcinoma (SCC) Staging. Experience in 30 Patients

Purpose: SCC represents nearly 90% of all oral malignancies, with an increasing incidence. Accurate Tumour-Node-Metastasis staging (TNM) is mandatory for planning surgical options and chemotherapy-radiotherapy management. Positron Emission Tomography (PET) using 18F-Fluorodeoxyglucose (FDG) provides functional information about tumoral tissues that may improve preoperative staging obtained by conventional morphologic procedures (CT-MRI). The purpose of this study is to evaluate the accuracy of FDG-PET in oral SCC staging and to compare those data from conventional and PET studies according to the pathologic results obtained from surgical specimen.Methods: A prospective study of 30 patients was carried out, through a 26 months period. Inclusion criteria include positive biopsy for Oral SCC, no other malignancies during the past 5 year and surgery as preferred therapeutic option. All patients underwent CT, MRI, and FDG-PET studies consecutively. Results obtained from conventional and PET preoperative staging were compared with those from postoperative histopathological studiesResults: FDG-PET modified preoperative staging obtained by conventional morphologic studies in 21% cases, which was confirmed postoperatively by histological findings. Kappa test showed higher values for PET studies (0.89) than conventional studies (0.41), when compared with postoperative controlConclusion: FDG-PET may be helpful to improve the accuracy of conventional studies in oral SCC preoperative TNM staging, although no definitive conclusions can be withdrawn due to the limited size of the sample. Modifications of preoperative staging showed by PET are a matter of controversy and must be kept in mind for further studies.

Comparison of systemic cytokine levels in patients with acute respiratory distress syndrome, severe pneumonia, and controls

BACKGROUND

The inflammatory response has been widely investigated in patients with acute respiratory distress syndrome (ARDS) and pneumonia. Studies investigating the diagnostic values of serum cytokine levels have yielded conflicting results and only little information is available for the differential diagnosis between ARDS and pneumonia.

METHODS

Clinical and physiological data, serum concentrations of tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta and IL-6, and quantitative cultures of lower respiratory tract specimens were obtained from 46 patients with ARDS and 20 with severe pneumonia within 24 hours of the onset of the disease and from 10 control subjects with no inflammatory lung disease. Cytokine concentrations were compared between groups and determinants in addition to the diagnosis were tested.

RESULTS

Serum TNF-alpha levels were significantly higher in ARDS patients (67 (57) pg/ml) than in patients with severe pneumonia (35 (20) pg/ml; p = 0.031) or controls (17 (8) pg/ml; p = 0.007). For IL-1beta and IL-6 the observed differences were not statistically significant between patients with ARDS (IL-1beta: 34 (65) pg/ml; IL-6: 712 (1058) pg/ml), those with severe pneumonia (IL-1beta: 3 (4) pg/ml, p = 0.071; IL-6: 834 (1165) pg/ml, p = 1.0), and controls (IL-1beta: 6 (11) pg/ml, p = 0.359; IL-6: 94 (110) pg/ml, p = 0.262). TNF-alpha (standardised coefficient beta = 0.410, p<0.001) and IL-1beta (standardised coefficient beta = 0.311, p = 0.006) were most strongly associated with the degree of lung injury, even when the diagnostic group was included in the statistical model.

CONCLUSIONS

Serum TNF-alpha levels were higher in patients with ARDS than in those with severe pneumonia or in control subjects. Multivariate results suggest that the levels of systemic TNF-alpha and IL-1beta reflect the severity of the lung injury rather than the diagnosis.

Capnometric recirculation gas tonometry and weaning from mechanical ventilation

The aim of this study was to describe changes in regional intramucosal PCO(2) (Pr(CO(2)) measured with capnometric recirculation gas tonometry [CRGT]) in patients with acute respiratory failure, who proceed from mechanical ventilation to weaning. In addition, we compared the predictive power for the weaning outcome of CRGT measurements obtained during mechanical ventilation to the frequency/ tidal volume (f/VT) ratio. A total of 24 patients (31 weaning trials) were included in the study, but four of the 24 patients (17%) were excluded because of extubation failure. Of the remaining 27 weaning trials in 20 patients, 12 (44%) were unsuccessful. Changes observed in patients with weaning failure (increase in Pr(CO(2)) from 60.4 +/- 15.0 mm Hg in mechanical ventilation to 67.4 +/- 21.0 mm Hg, in weaning) were significantly different (p = 0.046) from those observed in patients with weaning success (fall in Pr(CO(2)) from 61.5 +/- 15.0 mm Hg in mechanical ventilation to 56.3 +/- 16.7 mm Hg in weaning). However, absolute values of Pr(CO(2)) were not significantly different between patients with weaning success and failure, neither during mechanical ventilation (success, 61.5 +/- 15.0 versus failure, 60.4 +/- 15.0 mm Hg, p = 0.848) nor during weaning (success, 56.3 +/- 16.7 versus failure, 67.4 +/- 21.0 mm Hg, p = 0.135). The best single predictor for weaning outcome was the f/VT ratio measured early during weaning (area under the curve: 0.844 +/- 0.081; adjusted odds ratio for threshold value </= 105: 42.0, 95% CI 3.8 to 469.1, p = 0.002). CRGT could confirm a significant increase in Pr(CO(2)) during weaning in patients who finally failed the weaning trial. However, differences between patients with weaning success and failure were small and CRGT did not replace or improve the predictive power of the f/VT ratio for weaning outcome.