Electron microscopy in the diagnosis of malignant fibrous histiocytoma of the lung presenting as metastasis to the maxillary gingiva.

A rare case of an initial presentation of a metastatic lesion on the gingiva, arising from malignant fibrous histiocytoma (MFH) of the lung is reported. The role of electron microscopy in the diagnosis of soft tissue sarcomas has been studied. The ultrastructural details of a MFH are described and illustrated. The patient died within 9 weeks of the initial presentation with a gingival mass as is normal in these cases. He developed metastatic disease of the liver, lymph nodes, and bone. The role of electron microscopy in the diagnosis of soft tissue sarcomas is discussed.

Is abdominal aortic calcification score a cost-effective screening tool to predict atherosclerotic carotid plaque and cardiac valvular calcification in patients with end-stage renal disease?

Abdominal aortic calcification (AAC), cardiac valvular calcification (CVC), and atherosclerotic carotid plaque (CP) are known cardiovascular risk factors. The accuracy of the AAC score in predicting CP and CVC in patients with end-stage renal disease (ESRD) is assessed in this study. Twenty-two consecutive prevalent dialysis patients (group 1) and 26 consecutive nondialysis stage V chronic kidney disease patients (group 2) were assessed for their demographic and laboratory variables. Lateral radiograph of the lumbosacral spine was used to assess the AAC score. CP and CVC were assessed using carotid sonography and echocardiogram, respectively. Prevalence of AAC, CP, and CVC in groups 1 and 2 was, respectively, 72.7%, 81.8%, and 72.7% and 76.9%, 80.8%, and 57.7%. AAC was strongly associated with CP and CVC in both groups (P < 0.001). Tests of accuracy for the AAC score as a predictor of CP and CVC showed sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratio of a positive test, and likelihood ratio of a negative test, respectively, in group 1: 83%, 75%, 93%, 50%, 3.32, and 0.23 and 85%, 77%, 87%, 70%, 4.5, and 0.29, and in group 2: 90%, 95%, 83%, 69%, 3.9, 0.41, and 82%, 91%, 77%, 71%, 4.1, and 0.21. Reproducibility of the AAC score among observers was acceptable. The AAC score can predict CP and CVC with moderate accuracy in ESRD patients. However, as our study was underpowered, the findings need validation in larger, adequately powered studies.

Hepatocytes produce tumor necrosis factor-α and interleukin-6 in response to Porphyromonas gingivalis.

BACKGROUND AND OBJECTIVE: The liver plays a major role in clearing systemic bacterial infections. In addition, inflammatory cytokines produced in the liver play a critical role in systemic cytokine levels. The aim of this study was to investigate the production of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) by hepatocytes in response to periodontal pathogens. MATERIAL AND METHODS: The mouse hepatic carcinoma cell line Hepa-1.6 and the mouse macrophage-like cell line RAW 264 were co-cultured in Transwell insert plates. Cells were stimulated with bacterial extracts prepared from Porphyromonas gingivalis and the induction of TNF-α and IL-6 was measured using real-time PCR and ELISA. RESULTS: After stimulation with bacteria, the induction of TNF-α and IL-6 was observed in RAW 264 cells and Hepa-1.6 cells. Significant reduction of TNF-α mRNA expression in Hepa-1.6 cells was observed after treatment with antibody to TNF-α. CONCLUSION: The results obtained in the present study show that P. gingivalis extract induces TNF-α and IL-6 in an in vitro liver model and that macrophage-derived TNF-α mediates the induction of TNF-α in hepatocytes.

The effect of butyric acid on adhesion molecule expression by human gingival epithelial cells.

BACKGROUND AND OBJECTIVE: Short-chain fatty acids, such as butyric acid, are detected in periodontal pockets and are thought to be involved in the initiation and progression of periodontal disease. In the present study, we examined the effects of butyric acid on adhesion molecule expression by human gingival epithelial cells. MATERIAL AND METHODS: The human gingival carcinoma cell line, Ca9-22, was cultured in media that contained different concentrations of butyric acid. RESULTS: Cell numbers were significantly decreased in a dose-dependent manner by butyric acid at concentrations of > or = 0.2 mM. The expression of intercellular adhesion molecule-1 mRNA was significantly increased 6 h after stimulation. By contrast, the expression levels of integrins alpha 6 and beta 4 were decreased. Similar results were obtained by flow cytometry. CONCLUSION: The results of the present study indicate that butyric acid alters the expression of adhesion molecules by Ca9-22 cells. The elucidation of the mechanism of action of butyric acid on the periodontium may help to clarify several aspects of the onset and progression of periodontal disease.

Microarray analysis of nicotine-induced changes in gene expression in a macrophage-like human cell line.

BACKGROUND AND OBJECTIVE: Cigarette smoking has been suggested as a risk factor for periodontitis. Thousands of components are present in cigarette smoke, including nicotine, which may play an important role in the observed effects of smoking on cell metabolism. However, the mechanisms underlying these effects are unclear. Using DNA microarrays, we monitored differentially expressed genes, responsive to nicotine, in a macrophage-like human cell line. MATERIAL AND METHODS: Human U937 cells were treated for 1 h, with or without 1.0 microg/ml of nicotine. For differentiation, cultures were incubated with 10 nm phorbol myristate acetate for 48 h. Analysis of gene expression was performed using a DNA microarray of 8500 genes. RESULTS: The expression of 4914 genes was detected. Screening was carried out on those genes whose expression in three separate experiments showed an average change of twofold or greater, and 118 up-regulated genes and 97 down-regulated genes were identified. Among these were genes related to inflammation and other immune responses, such as phospholipase A2 and interferon. Consistent with the array findings, we found similar changes in mRNA expression after analysis using the real-time polymerase chain reaction. CONCLUSION: The results suggest that nicotine causes excess inflammation and disturbs host defense mechanisms against pathogens.

Abnormalities in neuromuscular junction structure and skeletal muscle function in mice lacking the P2X2 nucleotide receptor.

ATP is co-released in significant quantities with acetylcholine from motor neurons at skeletal neuromuscular junctions (NMJ). However, the role of this neurotransmitter in muscle function remains unclear. The P2X2 ion channel receptor subunit is expressed during development of the skeletal NMJ, but not in adult muscle fibers, although it is re-expressed during muscle fiber regeneration. Using mice deficient for the P2X2 receptor subunit for ATP (P2X2(-/-)), we demonstrate a role for purinergic signaling in NMJ development. Whereas control NMJs were characterized by precise apposition of pre-synaptic motor nerve terminals and post-synaptic junctional folds rich in acetylcholine receptors (AChRs), NMJs in P2X2(-/-) mice were disorganized: misapposition of nerve terminals and post-synaptic AChR expression localization was common; the density of post-synaptic junctional folds was reduced; and there was increased end-plate fragmentation. These changes in NMJ structure were associated with muscle fiber atrophy. In addition there was an increase in the proportion of fast type muscle fibers. These findings demonstrate a role for P2X2 receptor-mediated signaling in NMJ formation and suggest that purinergic signaling may play an as yet largely unrecognized part in synapse formation.

Experience of anatomy demonstrators in Tamil Nadu, India.

Questionnaires were sent to 118 previous holders of demonstrator posts in anatomy at the Christian Medical College, Vellore, India, in order to determine the role of these posts in the medical profession. Sixty-three (94%) of the respondents had postgraduate medical qualifications. Forty-four (66%) of the respondents were surgeons, and 23 (34%) were in non-surgical fields. Thirty-eight (57%) had jobs that involved teaching. Almost all the respondents found the teaching experience useful in their careers and especially those respondents who had qualified in surgical specialties rated their experience reviewing anatomy very highly. The usefulness of this posting is discussed.

A monkey model for enterohemorrhagic Escherichia coli infection.

Adult Macaca radiata (n=22) were infected intragastrically with 10(12) Escherichia coli O157:H7 strain 84-01, which produces Shiga toxins 1 and 2. Clinical symptoms and bacterial excretion were documented in each monkey for a specified time period before they were killed. At necropsy, samples were obtained for culture and histologic and ultrastructural examination. Seventeen monkeys had diarrhea: E. coli O157 was isolated from postinfection stool samples from all monkeys and from autopsy cultures for 14 of 22 monkeys. Histologic examination showed attaching-effacing lesions, which appeared at 12 h and persisted for 7 days, in 12 monkeys. Widening of the intercellular spaces, degeneration and vacuolization of the epithelial cells, epithelial tufting, extrusion of epithelial cells, and neutrophilic infiltration were characteristic features seen in 20 of the 22 infected monkeys but not in 4 control monkeys. This monkey model closely parallels the early stages of the disease produced by E. coli O157:H7 and would be useful in the further study of pathogenic mechanisms and prevention methods in enterohemorrhagic E. coli infections.

Vimentin, cytokeratin 8 and cytokeratin 18 are not specific markers for M-cells in human palatine tonsils.

Standard immunohistochemical methods were used to detect the presence of vimentin, cytokeratin 8, cytokeratin 18, macrophages and Langerhans cells in the human tonsillar epithelium in formalin-fixed and frozen tissue specimens. Vimentin detection was restricted to infiltrating cells of the lymphoid series, dendritic and vascular endothelial cells. All epithelial cells were negative. Cytokeratin 8 and 18 were readily detected in a large proportion of epithelial cells lining the crypt, but these cells bore no resemblance to the intestinal M-cells. Langerhans cells and macrophages were seen in both the oropharyngeal and crypt epithelium and were more common in the latter. This study confirms the presence of antigen-presenting cells, macrophages and Langerhans cells in the tonsillar epithelium and shows that intermediate filament proteins, vimentin, cytokeratin 8 and 18 are unreliable markers for human tonsillar M-cells, if indeed such cells exist in human tonsils.

Glomerular injury induced in mice by intraperitoneal injection of Shiga-like toxins.

BACKGROUND AND OBJECTIVES: Shiga-like toxins I and II (Stx1 and Stx2) play an important role in the pathogenesis of renal disease by causing renal microvascular injury. A murine model was used to study glomerular lesions produced by Stx1 and Stx2. METHODS: Swiss albino mice of the Rockefeller strain were inoculated intraperitoneally with LD(50) doses of endotoxin-free Stx1 of Stx2 and observed for signs of disease. Samples of renal cortical tissue from mice were examined with the electron microscope. RESULTS: the mice developed systemic and neurological symptoms including hind limb paralysis and generalised convulsions. Renal arteriolar damage and glomerular endothelial cytoplasmic swelling, vacuolation, lysis and intravascular coagulation were present and resembled the microangiopathy seen in renal biopsies from patients. INTERPRETATION AND CONCLUSIONS: these experiments establish the role of Stx1 and Stx2 in glomerular vascular injury and provide a model for studying the pathogenesis of Shiga-like toxin related microangiopathy.

Salicylate inhibits fimbriae mediated HEp-2 cell adherence of and haemagglutination by enteroaggregative Escherichia coli.

Enteroaggregative Escherichia coli (EAggEC) are associated with both acute and persistent diarrhoea in children. Bowel colonisation due to fimbrial adherence factors appears to play a major role in the disease process. In this study, we investigated the effect of sodium salicylate and 5-aminosalicylic acid on adherence of a type strain and 40 clinical isolates of EAggEC to HEp-2 cells and erythrocytes from different species. Growth in the presence of 10 mM salicylate resulted in markedly decreased adherence to tissue culture cells with 33/40 (82.5%) isolates, and was also associated with inhibition of haemagglutination in 20/33 (60.6%) isolates. Complete or partial inhibition of adherence was also seen in two of five isolates showing localised adherence and three of five isolates with diffuse adherence. Decrease in adherence was associated with decreased or absent expression of fimbriae in 28/40 (70%) of the EAggEC isolates, although production of outer membrane proteins was not affected. Salicylates appear to inhibit adherence mediated by fimbrial adhesins.

Problem in diagnostic imaging: pancreaticoduodenal arcade in splanchnic arterial stenosis.

This paper features a problem in diagnostic imaging in which a pre-transplant abdominal angiogram of a potential liver recipient shows filling of the hepatic artery via the superior mesenteric artery and the pancreaticoduodenal arcade. The routing of this unusual supply to the liver is explained by careful study of abdominal aortic angiograms and a sagittal MRI made through the aorta.

Morphology of the corpus callosum in human fetuses.

Shape and size of the human fetal corpus callosum of a relatively racially homogeneous southern Indian sample population were studied in midsagittal sections of formalin fixed brains. Length of corpus callosum and width of its genu, body, and splenium were measured and the data statistically analyzed. Presence of an isthmus between the body and splenium did not correlate with the measured variables. There was no significant gender difference. The variables correlated significantly among each other but only callosal length and genu width correlated with gestation age. Significant absolute increase occurred in callosal length and genu width, whereas body and splenium widths remained the same. Simple regression equations to estimate the callosal length and genu width for a given age are derived.

Introduction to histology through the use of familiar objects: innovative teaching module.

To introduce first-year medical students to fundamental concepts in histology and facilitate interpretation of two-dimensional images in the context of the three-dimensional nature of the object, a simple teaching module consisting of active exercises plus group discussions, using familiar objects from everyday use, was planned. In the process of mentally reconstructing sections through familiar objects, and representing in diagrams the appearance of these sections, students learned the use of common histology terms; the value of studying sections in series and at different planes; and spatial relationships of a) a nucleus within a cell, and b) tissue components within solid and hollow organs. Their understanding of these concepts was found to be good when evaluated by a multiple-choice-questions test, suggesting that this is an effective method for introducing beginners to fundamentals of histology.

[The effect of self-enhancement expectation on selection of comparisons as a self-assessment strategy].

Selection of others for comparison influences the outcome of self-assessment. The present study attempted to examine the effect of expectation for self-enhancement on strategic selection of comparisons. A questionnaire study was conducted with 169 undergraduates, who responded to four sets of questions. First, they listed ten abilities each for three areas that desired to acquire in high-level, in average-level, and undesired to acquire. Then, they evaluated themselves in comparison with others on the thirty abilities, and indicated whom they chose as comparisons. Finally, perceived probabilities were assessed of acquiring each ability. Results showed that selection of superior others was more when evaluated abilities were desired to acquire in high-level and perceived probability high than otherwise. This suggested that comparison with superior others was made if expectation for self-enhancement was high. The expectation therefore affects the likelihood of self-assessment behavior, and self-assessment is a necessary component of future self-enhancement.

[Self-assessment of ability and expectation of self-enhancement].

This study examined how the level of desire to acquire an ability and the perceived probability that it may be acquired affect self-assessment of the ability. From three categories, (1) desire to acquire is strong and desired level of acquisition is high, (2) desire is strong and desired level of acquisition is average, and (3) desire is weak, ten abilities each were chosen by each of 77 undergraduates. They also indicated the perceived probability that each ability might be acquired. Then, self-assessment behavior for each ability was measured with the choice and preference among four tasks that differed in terms of ability diagnosticity. The main results were as follows: (a) High-diagnostic tasks were chosen more often than the others, regardless of the desire to acquire and the probability. (b) Preference for high-diagnostic tasks was stronger when the desired acquisition level was high or average and the perceived probability was high. (c) Subjects' reason for self-assessment was their need to acquire accurate self-knowledge. The results suggest that expectation of future self-enhancement affects the likelihood of self-assessment behavior.

[Effects of goals and perceived probabilities of goal attainment on self-assessment].

This study examined effects of explicitness of achievement goals and perceived probabilities of goal attainment on self-assessment. Subjects were 251 undergraduate students. They were first asked, as measure of explicitness of goals, if they hope to acquire good capability in scientific research, and second how they perceived their probabilities of goal attainment. Self-assessment behavior was measured by task choice and task preference for four tasks which differ in diagnosticity. The main results were as follows. (a) The most diagnostic task was chosen more often by the subjects who both had an explicit goal and perceived the probability of goal attainment high, and those who didn't have an explicit goal and perceived the probability low. (b) On task preference, the effects of goal explicitness and perceived probability were not found. These results suggest that self-assessment be done for future self-enhancement.

Enteric vascular endothelial response to bacterial endotoxin.

The response of enteric vasculature to endotoxin was examined at the ultrastructural level using a murine model of endotoxin-induced acute diarrhoea. Morphological changes indicative of endothelial damage were evident as early as 15 minutes following endotoxin challenge. These changes, characterized by widening of intercellular spaces, increased microvillous projections and the appearance of stress fibres, preceded the leucocytic response. Endothelial damage increased with time, being associated with progressive degenerative changes in the plasma membrane, cytoplasm and organelles, ultimately leading to desquamation. These latter changes were temporally associated with margination of neutrophils and platelet adhesion to the denuded subendothelium. The venules were the primary site of these changes while the capillaries were the least affected. The arterioles were markedly constricted with minimal endothelial damage. These changes suggest that the enteric vascular endothelium may be an important target organ, and the resultant endothelial injury may have implications in host responses to endotoxin.

[The function of self-esteem motive on the process of self-image bias arousal].

The present study investigated the influence of active or passive self-esteem motive (SEM) on the process of self-image bias arousal in person perception. Subjects were 45 female college students and each were assigned to one of three experimental conditions: (a) active SEM aroused (ACTIVE), (b) passive SEM aroused (PASSIVE), (c) either SEM not aroused (CONTROL). The change in frequency of using self-desirable and self-undesirable dimensions in the descriptions of stimulus person's personality was examined among three conditions: the frequency before SEM being aroused was subtracted from the frequency after SEM being aroused. The results showed that the frequency of using self-desirable dimensions was not increased in ACTIVE condition compared with those in the other two conditions. On the other hand, the frequency of using self-undesirable dimensions was significantly decreased in PASSIVE condition than those in the others. These results suggested that there was self-image bias which decreased the importance of self-undesirable dimensions in person perception when the passive SEM was aroused.