Coexpression of p53 and Ki 67 and lack of c-erbB2 expression in oral leukoplakias in India

Oral cancer is commonly preceded by premalignant lesions and conditions. The clinician's ability to identify lesions at an increased risk of cancer development is critical for its control. The purpose of this study was to compare the expression of tumor suppressor gene p53, proliferation marker Ki-67, and oncogene c-erbB2 and to evaluate the relevance of their co-expression in the diagnosis of, and prognosis for, oral leukoplakia. In the present study, the expression of biomarkers was studied immunohistochemically in 55 cases of leukoplakia (26 without dysplasia, 29 with dysplasia) and 10 cases of normal epithelia. The Labeling Indices (LI) of p53 and Ki-67 were found to increase significantly with an increase in the grade of dysplasia. A significant correlation was also found between the LI of p53 and that of Ki-67. It was also observed that c-erbB2 expression was only cytoplasmic, indicating incomplete receptor degradation. Hence, it can be concluded from the present study that the increased expression of p53 and Ki-67 with an increase in the grade of dysplasia suggests that their co-expression may be used for the identification of high-risk lesions. Also, c-erbB2 has no pathogenetic role in early carcinogenesis in the studied population, although incomplete receptor degradation, as evidenced by cytoplasmic staining, may indicate an early change.

Comparative study of Candida in oral submucous fibrosis and healthy individuals / Estudo comparativo de Candida em fibrose submucosa oral e indivíduos saudáveis

PURPOSE: Oral submucous fibrosis (OSMF) is a high-risk precancerous condition that predominantly affects Indian youngsters due to the habit of gutkha chewing. Candida may play a role in the etiopathogenesis of premalignant and malignant lesions. The aim of this study is to compare the incidence, intensity, and species of Candida found in OSMF patients and healthy individuals. METHODS: This study included 20 OSMF patients and 20 healthy controls. A detailed history of each patient was recorded along with a clinical examination. Samples were collected with the oral rinse technique and cultured on Sabouraud's agar medium. The isolated yeast species were counted and identified based on Gram staining, a germ tube test, chlamydospore formation and a sugar assimilation test. RESULTA: In total, 40 percent of OSMF patients and 15 percent of healthy controls yielded Candida organisms on culture. C. albicans was the predominant species isolated, but C. krusei and C. tropicalis were also identified. Gender, gutkha habit and clinical staging had no influence on the candidal carriage in OSMF patients. CONCLUSION: The incidence and intensity of Candida (primarily C. albicans) was greater in OSMF patients than in healthy controls, but these findings were within the normal limit (3-47 percent). Therefore, Candida may not be an etiologic factor in malignant transformation. However, controversy still exists over whether the chewing of betel quid in cases of OSMF has an inhibitory effect or promotes the adherence and invasion of Candida.

OBJETIVO: Fibrose submucosa oral (FSO) é uma condição pré-maligna de alto risco que predominantemente afeta jovens da Índia devido ao hábito de mascar 'gutkha'. Candida pode ter um papel importante na etiopatogenia de lesões pré-malignas e malignas. O objetivo deste estudo foi comparar a incidência, intensidade e Candida spp encontradas em pacientes com FSO e em indivíduos saudáveis. METODOLOGIA: Este estudo incluiu 20 pacientes com FSO e 20 controles saudáveis. Obteve-se de cada sujeito uma história detalhada e exame clínico. As amostras foram coletadas com uma técnica de enxágue bucal e cultivadas em meio Agar Sabouraud. As espécies isoladas foram contadas e identificadas com base em coloração Gram, teste de tubo de ensaio e teste de assimilação de açúcar. RESULTADOS: No total, 40 por cento dos pacientes com FSO e 15 por cento dos controles saudáveis apresentaram resultado positivo de cultura para Candida. C. albicans foi a espécie predominante isolada, mas C. krusei e C. tropicalis também foram identificados. O sexo, hábito de mascar 'gutkha' e estadiamento clínico não influenciaram a presença de fungos nos pacientes com FSO. CONCLUSÃO: A incidência e intensidade de Candida (primariamente C. albicans) foi maior nos pacientes com FSO que nos sujeitos controle, mas estes achados estavam dentro dos limites normais (3-47 por cento). Portanto, Candida pode não ser um fator etiológico na transformação maligna. Entretanto, ainda há controvérsias se o hábito de mascar 'betel' em casos de FSO teria um efeito inibidor ou promoveria a aderência e invasão de Candida.

Comparative study of adherence of oral Candida albicans isolates from HIV sero-positive individuals and HIV sero-negative individuals to human buccal epithelial cells.

Aim: Candida albicans occurs as a commensal of the gastrointestinal tract. Under predisposing conditions, candida can produce a broad array of infections. HIV seropositive individuals show increased oral colonization compared to the HIV seronegative healthy individuals. C. albicans shows a variety of pathogenic factors. We have studied one such factor here; the adherence property of C. albicans isolated from HIV seropositive individuals and HIV seronegative to Human Buccal Epithelial Cells (HBEC) of normal healthy individuals. Materials and Methods: Concentrated oral rinse specimen were collected from 50 healthy volunteers (control group) and 25 HIV positive individuals (test group) and used for isolation of C. albicans. Adherence assay was done using C. albicans isolates from both groups on HBEC collected from HIV sero-negative, normal individuals. The adherence assay method described by Kimura and Pearsall was used with minor modification. Statistical Analysis Used: The results of Adhesion assay were subjected to statistical analysis using student "t" test. Results: C. albicans isolated from both the groups were tested for their adherence property to normal HBEC. The isolates from test group showed more adherence to HBEC compared to those of the control group, with average rate of adherence being 56.6%. The control group showed average adherence rate of 29.1%. This was statistically significant with p value equal to 0.05. Conclusion: C. albicans from HIV infected individuals showed significant rise in degree of adhesion to the buccal epithelial cells than the isolates from healthy controls, suggesting the enhancement of virulence factors such as adherence in the presence of predisposing condition.

Comparison of Phenotypic and Genotypic methods for Pyrazinamide susceptibility testing.

Objectives: To evaluate Pyrazinamide (PZA) susceptibility results obtained by phenotypic MGIT 960 TB system against enzymatic Pyrazinamidase assay and genotypic pncA gene sequencing. To find the prevalence of infections caused by M. bovis in PZA resistant M. tuberculosis complex isolates. Methods: 33 consecutive PZA resistant and 30 consecutive PZA susceptible isolates reported for PZA susceptibility testing by MGIT 960 TB system were included in this study. Presence of active pyrazinamidase enzyme was sought by using the Wayne assay. The pncA gene was amplified by PCR and then sequenced to screen mutations. All the PZA resistant isolates were further spoligotyped to identify M. bovis, if present. Results: Of 33 PZA resistant strains by MGIT 960, 31 were Wayne assay negative and two were positive. Of the 30 susceptible PZA strains six were Wayne assay negative reporting false resistance. PncA gene sequencing revealed that 32 of the 33 MGIT PZA resistant isolates had diverse nucleotide changes scattered throughout the pncA gene (one isolate did not show any mutation). Of the 30 phenotypically susceptible isolates, 21 were wild types whilst nine isolates showed the presence of a silent mutation C-T at codon 195. Fifteen mutations found in this study has not been described earlier. Not a single isolate of M. bovis was detected among PZA resistant M. tuberculosis complex isolates. Conclusion: MGIT 960 showed better concordance with sequencing results in comparison with Wayne assay. In present study, a high proportion (85%) of MDR-TB isolates from patients receiving anti-TB treatment were found to be resistant to PZA.

Phenotypic detection of inducible clindamycin resistance among Staphylococcus aureus isolates by using the lower limit of recommended inter-disk distance.

CONTEXT: Clindamycin is one of the important alternative antibiotics in the therapy of Staphylococcus aureus, particularly in methicillin-resistant S. aureus (MRSA) infections. Inducible clindamycin resistance (iMLS B--inducible Macrolide-Lincosamide-Streptogramin B resistance) is a critical factor in antimicrobial susceptibility testing. AIMS: To know the rate of inducible clindamycin resistance among clinical isolates of Staphylococcus aureus in our hospital by Disk approximation test (D-test) using the average recommended inter-disk distance and comparing the results with that of D-test using the lower limit of recommended inter-disk distance. MATERIALS AND METHODS: A total of 51 erythromycin-resistant and clindamycin-susceptible S. aureus isolates were subjected to disk approximation testing with 21 +/- 1 mm and 15 mm edge-to-edge distance between the clindamycin and erythromycin disks. STATISTICAL METHODS: Z-test levels. RESULTS: Among 51 erythromycin-resistant and clindamycin-susceptible S. aureus isolates, 25 (49%) were recorded as inducible clindamycin resistant by D-test with 21 +/- 1 mm edge-to-edge distance between the clindamycin and erythromycin disks. When we re-tested all the 51 strains by D-test with 15 mm inter-disk distance, we identified 14% more iMLS B strains previously reported as D-test negative. Z-test for MRSA indicates that 15 mm edge-to-edge distance has significant advantage. CONCLUSIONS: Since the incidence of inducible clindamycin resistance is high (63% in our study), accurate identification of inducible clindamycin resistance is important to prevent therapeutic failure in infections caused by these strains. We suggest the use of D-test with 15 mm edge-to-edge inter-disk distance for detecting iMLS B .