Virulent Mycobacterium fortuitum restricts NO production by a gamma interferon-activated J774 cell line and phagosome-lysosome fusion

The virulence of different isolates of Mycobacterium has been associated with two morphologically distinguishable colonial variants: opaque (SmOp) and transparent (SmTr). In this report we used an in vitro assay to compare macrophage (Mphi) responses to SmOp and SmTr Mycobacterium fortuitum variants, taking advantage of the fact that these variants were derived from the same isolate. Cells preactivated or not with gamma interferon (IFN-gamma) were infected with SmOp or SmTr M. fortuitum. We showed that SmOp and SmTr induced different levels of nitric oxide (NO) production by IFN-gamma-stimulated Mphi. Indeed, the amount of IFN-gamma-induced NO production by J774 cells was 4.8 to 9.0 times higher by SmOp (23.1 to 37.7 micro M) compared to SmTr infection (3.9 to 4.8 micro M) (P = 0.0332), indicating that virulent SmTr bacilli restricted NO production. In addition, IFN-gamma-induced NO production by Mphi was higher when correlated with reduction of only avirulent SmOp bacillus viability. SNAP (S-nitroso-N-acetyl-DL-penicillamine)-induced NO production did not modify SmTr viability, indicating its resistance to nitrogen radicals. Electron microscopy studies were performed to evaluate the capacity of phagosomes to fuse with lysosomes labeled with bovine serum albumin-colloidal gold particles. By 24 h postinfection, 69% more phagosome-containing SmOp variant had fused with lysosomes compared to the SmTr-induced phagosomes. In conclusion, these data indicate that virulent SmTr bacilli may escape host defense by restricting IFN-gamma-induced NO production, resisting nitrogen toxic radicals, and limiting phagosome fusion with lysosomes.     

ThermoSpot in the detection of neonatal hypothermia

Thermal care is a critical part of caring for neonates. The need to identify simple, affordable and effective tools for detecting hypothermia in newborn infants that can be used by mothers and other caregivers in resource-poor countries remains crucial in our efforts to reduce perinatal and neonatal mortality and morbidity. The objective of this study was to determine the effectiveness of ThermoSpot in detecting hypothermia in newborn infants in a developing country. The prevalence of hypothermia (< 36 degrees C) in our study population was 51.4%. The ThermoSpot disc indicated green (normothermia) in 82% of infants whose axillary temperature was between 32 and 35.9 degrees C. However, the disc had a 100% specificity and positive predictive value at body temperatures below 36 degrees C and axillary temperatures below 36 degrees C or above 37.5 degrees C. Sensitivity, negative predictive value and accuracy were 19%, 52% and 57%, respectively. Mortality was significant in infants with black or blue ThermoSpot disc colours compared with green. For ThermoSpot discs placed on the abdomen, the risk of dying was 2.67 times higher if the disc colour was black compared with green and 2.43 times higher if the disc colour was blue compared with green. Similarly for ThermoSpot discs placed in the axilla, the risk of dying was 2.54 times higher if the disc colour was black and 2.5 times higher if the disc colour was blue as opposed to green. There is a need to improve the sensitivity and accuracy of ThermoSpot in detecting hypothermia before its widespread use.     

Msx1 is a regulator of bone formation during development and postnatal growth: in vivo investigations in a transgenic mouse model

The present study is devoted to Msx1 distribution and function from birth to 15 months, events and periods still unexplored in vivo using Msx1 knock in transgenic mice. The study is focused on the mandible, as an exemplary model system for Msx1-dependent neural crest-derived skeletal unit. The transgenic line enabled study of morphological abnormalities in Msx1 null mutation mice and Msx1 protein expression in Msx1+/- heterozygous mice. In Msx1 null mutation, the most striking feature was an inhibition of the mandibular basal convexity, the absence of teeth and alveolar bone processes, and absence of endochondral ossification in the mandibular condyle. At birth, in Msx1+/- heterozygous animals, we identified for the first time a double Msx1 aboral-oral and disto-proximal gradient field developmental pattern located in the low border of the mandibular bone in relation with this bone segment modeling. Msx1 expression involved both osteoblast and osteoclast cells. A distinct pattern characterized bone surfaces: Periosteum osteoblast differentiation was related to Msx1 down-regulation, while in the endosteum both differentiated osteoblasts and osteoclasts expressed the homeoprotein. In postnatal stages, Msx1 expression was maintained in the alveolar bone processes and dento-alveolar cells in relation with tooth function. Our data suggest that Msx1 play a role in a site-specific manner not only in early patterning but also in skeletal growth and modeling by acting on heterogenous bone cell populations.     

Genetic organisation of <Emphasis Type="Italic">Iris yellow spot virus</Emphasis> M RNA: indications for functional homology between the G<Subscript>(C)</Subscript> glycoproteins of tospoviruses and animal-infecting bunyaviruses

Summary.  The complete nucleotide sequence (4838 nucleotides) of Iris yellow spot virus (IYSV) M RNA indicates, typical for tospoviruses, the presence of two genes in ambisense arrangement. The vRNA ORF codes for the potential cell-to-cell movement (NSm) protein (34.8 kDa) and the vcRNA ORF for the viral glycoprotein (G1/G2) precursor (128.6 kDa). Multiple sequence alignment of the NSm and G1/G2 precursor proteins of IYSV with those of other tospoviruses, showed highest homologies to Peanut bud necrosis virus (PBNV) and Watermelon silver mottle virus (WSMV). The potential cell-to-cell movement protein of tospoviruses is highly conserved (40–70% identity), with the exception of the first 60 N terminal amino acids, a domain that clearly diverged. For the G1 and G2 viral glycoproteins, blast searches revealed a significant homology between the C-terminally located tospoviral G1 (G_(C)) protein with the counterpart of the animal-infecting bunyaviruses, suggesting a functional homology for these proteins. Received January 15, 2002; accepted July 10, 2002     

Polymorphous low-grade adenocarcinoma of the salivary glands with transformation to high-grade carcinoma

AIMS: Polymorphous low-grade adenocarcinoma of the minor salivary glands is an infiltrative neoplasm characterized by bland-looking tumour cells arranged in diverse architectural patterns. It is considered to be of low-grade malignant potential in that nodal metastases are seen in only a minority, and distant spread is rare. Even more unusual is the transformation of polymorphous low-grade adenocarcinoma to a histologically high-grade carcinoma, i.e. dedifferentiation. In this paper, we describe the clinicopathological and immunohistochemical findings in two further examples. METHODS AND RESULTS: Two patients presented each with a tumour of the palate. Histopathological examination showed the typical morphological, cytological and immunohistochemical features of a polymorphous low-grade adenocarcinoma. In one case there was a second component of high-grade carcinoma showing nuclear atypia, markedly increased mitotic activity and MIB1 index, as well as prominent zones of necrosis. It expressed epithelial markers and androgen receptors, and thus resembled salivary duct carcinoma. Similar tumour tissue was observed in one of the cervical nodal metastases, which was biopsied at the same time as the palate. In the second patient, a high-grade component was discovered when the tumour recurred in the palate 13 years after the initial biopsy. Whilst morphologically similar to that in first case, there were significant immunohistochemical differences such as retention of some of the polymorphous low-grade adenocarcinoma profile and absence of androgen receptor expression. CONCLUSIONS: Polymorphous low-grade adenocarcinoma was first described relatively recently, and as experience with it continues to accumulate, it is becoming clear that late recurrences and metastases, whilst still infrequent, may not be quite as rare as previously thought. Reports of histological transformation are even scarcer, and most occurred at least 13 years after the polymorphous low-grade adenocarcinoma was initially recognized. It is a real possibility that this phenomenon, like clinical progression, may also be encountered more often as time passes. Therefore, we believe that, whilst polymorphous low-grade adenocarcinoma is certainly far less aggressive than, for example, adenoid cystic carcinoma, it nevertheless remains a true malignancy with a potential to prove fatal in a minority of patients.     

A sulphated fucan from the Laminaria abyssalis inhibits the human T cell lymphotropic virus type 1-induced syncytium formation in HeLa cells

This work evaluated the effect of a sulphated fucan extracted from the Laminaria abyssalis marine algae on the human T cell lymphotropic virus type 1 (HTLV-1)-induced syncytium formation. The experiments were carried out in HeLa cells cocultured with a HTLV-1-infected T cell line (C91/PL cells) in the presence of the sulphated polysaccharide at concentration below that corresponding to the ED50. The sulphated fucan inhibited almost 100% of the syncytium formation at concentration of 100 microg/mI and was still active (>95%) at a concentration of 25 microg/ml. It was also observed that the best inhibition occurred when the compound was added in the first 2 h of the cell-to-cell contact. This is the first report showing that a purified sulphated polysaccharide, extracted from marine algae, is able to inhibit the cell-to-cell contact essential for the spreading of the HTLV-1.     

Morphometric study of the spleen in chronic Chagas' disease

There is frequently an increase in spleen size in infectious systemic and chronic venous congestion. The aim of this report was to perform a comparative study of the spleen tissue of chagasic or nonchagasic autopsied patients with or without congestive heart failure. Evaluations were made of 111 cases. Connective tissue intensity, follicular density and area, and follicular arterioles wall area were determined through the morphometric study. The connective tissue was similar in all groups. The density of the lymphoid follicles was significantly less among the chagasic cases (P = 0.032). The follicular area was larger among the chagasic cases and in the chagasic group with congestive heart failure. The chagasic group without congestive heart failure presented a greater area of follicular arteriole walls. Therefore, the spleen modifications in chronic Chagas' disease could be a consequence not only of the heart failure but also of the Chagas infection itself.     

High prevalence of asymptomatic Plasmodium vivax and Plasmodium falciparum infections in native Amazonian populations

The epidemiology of malaria in 2 riverine localities in Rond?nia, Brazilian western Amaz?nia, was assessed by a 1-year study at Portuchuelo, and a cross-sectional survey at riverine communities at Rio Machado (= Ji-Parana). Plasmodium spp. infections were diagnosed by light microscopy and by polymerase chain reaction (PCR) amplification of ribosomal DNA. PCR was 6-7 times more efficient than microscopy for detecting plasmodial infections. Both Plasmodium vivax and Plasmodium falciparum infections occurred as asymptomatic and symptomatic forms of the disease. The relation between symptomatic and asymptomatic clinical forms was roughly similar for both species of Plasmodium. Symptomless patients were monitored for 2 months. The prevalence of symptomless infections was 4-5 times higher than the symptomatic ones--respectively, 20% and 4.6% for Portuchuelo and 49.5% and 10% for Ji-Parana. Symptomatic malaria occurred mostly in patients in younger age groups. In contrast, there was a significant association of symptomless malaria with older age groups (medians of 26.5 and 21 years, respectively, for Portuchuelo and Ji-Parana), whereas the age medians for symptomatic malaria were 14 and 8 years, respectively, in the 2 regions. Symptomatic malaria also was more prevalent in groups living for shorter times in Amaz?nia (13 and 4 years, respectively, for Portuchuelo and Ji-ParanA) as compared with symptomless malaria, which was more prevalent in groups living for longer periods in the region (medians of 25.5 and 18 years, respectively, for Portuchuelo and Ji-Paraná). The high prevalence of symptomless malaria may pose new problems for the currently adopted strategy for the control of malaria in the Amazonian region, which is essentially based on the treatment of symptomatic patients.     

Quality of life and peripheral lymphedema

Evaluation of the health-related quality of life (QOL) is becoming commonplace, seeking to provide information about the everyday well-being of a patient. This work examined the QOL of 23 consecutive patients with lymphedema of the upper or lower extremities. Five were men and the other eighteen were women. Their ages ranged from 19 to 74 years (mean 48.3). After clinical examination, and with informed consent of each patient, they were assessed by a psychologist and submitted to a QOL test (SF-36). For controls, twenty-three women and five men with age range of 28 to 66 years (mean 47) were similarly evaluated. The results showed the lymphedema group had a statistically significantly reduced QOL in both physical and mental health as well as social interaction.