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Biomedical subjects

S Sethi

Publications and source records attributed to S Sethi.

At least 73 records · Page 4Linked to original sources
PubMed1998

Breast carcinoma associated with necrotic granulomas in axillary lymph nodes.

From a series of 100 consecutive breast carcinomas with axillary lymph node metastases, two cases of necrotic granulomas in the nodes are presented. Lymph nodes in each case were characterized by areas of necrosis surrounded by a palisade of cells resembling histiocytes as seen in a rheumatoid nodule. Although the initial impression was that of a reactive granuloma, when immunostained for keratin and EMA, the areas of necrosis showed positive staining for keratin and EMA in a cytoplasmic pattern. The surrounding palisade of cells stained with histiocyte markers, while the necrotic area itself was negative. Staining for both estrogen and progesterone markers was also negative. Staining of nine lymph nodes with caseating granulomas not associated with carcinoma with the same panel of antibodies revealed no staining except for irregular, noncellular staining with EMA. This pattern of necrosis in axillary lymph nodes from two cases of breast carcinoma was interpreted as evidence of necrotic metastatic tumor cells. Necrosis in axillary lymph nodes associated with invasive breast cancer should arouse suspicion for metastasis.

Axilla↗
PubMed1998

Diagnostic significance of 'benign pairs' and signet ring cells in fine needle aspirates (FNAs) of the breast.

Most breast mass lesions are readily characterized by FNA with cytodiagnosis. Occasionally, benign but markedly proliferative lesions are diagnostically difficult to separate from well differentiated malignancies. We present information pertaining to the diagnostic significance of two cytologic findings observed in breast aspiration specimens, namely pairs of stripped bipolar nuclei and signet ring cells (SRC). We have evaluated aspirate smears from 219 cases of histologically proven benign (n = 114) and malignant (n = 105) breast lesions. Both singlets and pairs of bipolar nuclei and SRC were enumerated, and their numbers were correlated to histological diagnosis. Closely associated pairs of stripped bipolar nuclei were found in 68% of benign lesions compared with only 3.8% of carcinomas, establishing their presence as a highly specific indicator of a benign process. Large numbers of such 'benign pairs' also favoured the diagnosis of fibroadenoma. SRC were identified in 66% of histologically proven carcinomas (67% of ductal and 70% of lobular). SRC were also present in 10% of histologically benign cases. In the malignant cases, SRC were most frequently noted in a single cell distribution or within small, loosely cohesive tissue fragments. In the benign instances, SRC were most commonly noted within large fragments, and many of these cells were proved by immunohistochemical reactions to be vacuolated myoepithelial cells. We conclude that the presence of bipolar nuclei in closely associated pairs suggests benignity and aids in the subclassification of benign breast masses. In addition, the presence of SRC does not aid in the classification of tumour subtype (ductal vs lobular), and the occurrence of such cells in the proper context should prompt surgical biopsy.

Adenocarcinoma↗
PubMed1998

Disseminated candidosis in premature twins.

A unique case of disseminated candidosis in premature twins is presented where twin A developed disease soon after birth and died prior to the administration of antifungal therapy. On the other hand, twin B developed infection on the 26th day of birth but survived, though with sequelae (hydrocephalus), since he was promptly and accurately diagnosed and treated.

Candida albicans↗
PubMed1998

Prevalence of fungal species in patients with funguria.

Fungal isolates recovered from urine samples of high risk group of symptomatic patients (n = 446) over a period of 12 months were identified and prevalence of different species was determined. Four Candida species viz., Candida albicans, C. tropicalis, C. krusei and C. pseudotropicalis accounted for 84 per cent (205) of the yeast species isolated. Seven different species of Candida were recovered, besides 5.3 per cent (13) unidentified yeast. Most of the yeasts were identified within 48 h. Funguria poses a management problem in seriously ill patients.

Adolescent↗
PubMed1997

Diagnostic significance of signet ring cells in fine-needle aspirates of the breast.

Fine-needle aspiration (FNA) is a reliable and cost-effective procedure in the evaluation and management of breast lesions. One diagnostic dilemma that may sometimes arise is the finding of signet ring cells. The isolated finding of such cells in aspirate smears may be particularly problematic in cases of low cellularity or those with otherwise benign features. Although it is generally held that such cells are almost exclusively associated with carcinoma (particularly the lobular subtype), their significance in FNA smears has never been systematically evaluated. To establish their diagnostic utility, we evaluated aspirate smears from 150 cases of histologically proven benign (77) and malignant (73) breast lesions for the presence of signet ring cells, defined as those containing a prominent intracytoplasmic vacuole with nuclear displacement. Signet ring cells were identified in 71% of malignant cases (75% of ductal carcinomas and 71% of lobular carcinomas), mostly as single cells or within small, loosely cohesive tissue fragments. Such cells also present in 6% of histologically proven benign lesions, most commonly within large tissue fragments. Many of these cells were proven to be vacuolated myoepithelial cells, based on histologic correlation and immunostaining results using anti-muscle-specific actin. On the basis of these findings, we conclude that (1) the presence of signet ring cells within small loose tissue fragments or as single cells in FNA smears should prompt close clinical follow-up (including repeat FNA and perhaps surgical biopsy), regardless of smear cellularity, (2) the presence of signet ring cells in cases of adenocarcinoma does not predict a particular tumor subtype, and (3) rare benign breast lesions may contain signet ring cells, particularly within large tissue fragments, and do not, in isolation, warrant surgical biopsy to exclude malignancy.

Adenocarcinoma↗
PubMed1997

Human immune response to nontypeable Haemophilus influenzae in chronic bronchitis.

Nontypeable Haemophilus influenzae (NTHI) causes recurrent respiratory tract infections in patients with chronic bronchitis. To elucidate the human immune response to NTHI, sera from 2 patients with exacerbations of chronic bronchitis due to NTHI were characterized. Both patients developed new bactericidal antibodies following infection. Immunoblot assays with homologous strains revealed antibodies to many antigens, with minimal difference between pre- and postexacerbation sera. By contrast, whole cell radioimmunoprecipitation, which detects antibodies exclusively to epitopes exposed on the bacterial surface, revealed that both patients made new antibodies to a limited number of antigens following infection, including P2, the major outer membrane protein of NTHI. Adsorption experiments showed that strain-specific, surface-exposed epitopes on the P2 molecule are targets for bactericidal antibodies. These results indicate that new bactericidal antibodies following infection by NTHI recognize antigenically heterogeneous surface-exposed epitopes on P2 and other surface proteins of NTHI.

Antibodies, Bacterial↗
PubMed1997

Entomophthoromycosis due to Basidiobolus haptosporus.

This paper reports a case of entomophthoromycosis in a 40-year-old man who presented with an ulcerative wound and serosanguineous discharge after surgical removal of a fibrocystic mass. The serosanguineous discharge yielded Basidiobolus haptosporus, perhaps the first culture-proven case from a surgical wound.

Abdominal Muscles↗
PubMed1997

Antigenic characterization and analysis of the human immune response to outer membrane protein E of Branhamella catarrhalis.

Outer membrane protein E (OMP E) is a 50-kDa major OMP of Branhamella catarrhalis. Polyclonal antisera and four monoclonal antibodies (MAbs) to OMP E were generated to study its antigenic structure. All antibodies recognized epitopes in all 19 B. catarrhalis strains tested by immunoblot assays. By flow cytometry, it was determined that MAbs 1B3 and 9G10d recognized epitopes which are expressed on the surface of the intact bacterium, while MAbs IC11 and 7C10 recognized epitopes which were buried within the outer membrane. A competitive enzyme-linked immunosorbent assay showed that MAbs 1B3 and 9G10d recognize the same or closely related epitopes. Proteinase K treatment of whole bacterial cells revealed that MAbs 1B3 and 9G10d recognize a surface-exposed epitope located in the 17-kDa region towards the amino terminus of OMP E. The human serum and mucosal antibody responses to OMP E in adults with chronic bronchitis were studied. A majority of these patients had immunoglobulin A to OMP E in sputum supernatants. None of ten adults who experienced lower respiratory tract infections due to B. catarrhalis demonstrated a clear-cut rise in antibody titer to OMP E in serum or sputum supernatant. This study has demonstrated that OMP E has at least one surface-exposed epitope which is highly conserved among strains of B. catarrhalis and which is located in the amino-terminal 184 amino acids of the molecule.

Adult↗
PubMed1997

Antigenic heterogeneity and molecular analysis of CopB of Moraxella (Branhamella) catarrhalis.

Outer membrane protein (OMP) CopB, an iron-repressible 81-kDa major OMP of Moraxella (Branhamella) catarrhalis has been a major focus of investigation. To assess CopB as a potential vaccine antigen, we elucidated the degree of antigenic and sequence heterogeneity in this protein among strains of M. catarrhalis. Two monoclonal antibodies, 1F5 and 2.9F, which bind to surface-exposed epitopes on CopB recognized 60 and 70% of the strains, respectively. The degree of sequence heterogeneity in CopB was assessed by cloning and sequencing the CopB gene from two different strains of M. catarrhalis and comparing with the published sequence. There was 92 to 96% homology between the sequences at the nucleotide level and 90 to 95% homology at the amino acid level. The variability in the protein sequence is confined mainly to three moderately variable regions. Restriction fragment length polymorphism (RFLP) analysis of the CopB genes obtained from 20 diverse strains by PCR was performed. Ninety percent of the potential restriction sites in the constant regions and 47% of the potential restriction sites in the variable regions were present in the 20 strains, indicating that the pattern of variable and constant areas in the CopB gene is a general pattern among strains of M. catarrhalis. We conclude that the CopB gene is largely conserved among strains of M. catarrhalis and contains discrete regions which show moderate heterogeneity among strains.

Amino Acid Sequence↗
PubMed1996

Inhibition of phagocyte-endothelium interactions by oxidized fatty acids: a natural anti-inflammatory mechanism?

Diets rich in marine fish oil may protect against cardiovascular disease. Although the mechanisms involved in such protection are not known, fish oils have been reported to exert anti-inflammatory actions. For example, dietary fish oil supplementation was observed to profoundly decrease the numbers of monocytic cells adherent to endothelium overlying atherosclerotic lesions in pigs. We have therefore investigated the possibility that fish oil components-particularly n-3 polyunsaturated fatty acids (PUFAs)-might inhibit phagocyte-endothelium interactions. We have found that binding of a monocytic cell line (U937) to cultured endothelium (with cell adhesion molecules up-regulated by exposure to lipopolysaccharide (LPS), interleukin-1 alpha, tumor necrosis factor-alpha, or phorbol myristate acetate (PMA) is greatly decreased by pre-exposure of endothelial cells to n-3 and other PUFAs that are incidentally or purposefully oxidized; unoxidized PUFAs are completely ineffective. Decreased monocyte adherence probably derives from diminished up-regulation of endothelial cell adherence molecules VCAM-1 and ELAM-1. Oxidized n-3 PUFAs prevent LPS- or PMA-induced activation of transcription factor NF-kappa B and the consequent induction of mRNA for both cell adhesion molecules. Hydroperoxy fatty acids are the active principle in oxidized PUFAs because the activity (1) is predominantly organic soluble, (2) is obliterated by pretreatment of oxidized material with chemical reducing agents, and (3) is diminished by enzymatic reduction of organic hydroperoxides with glutathione/glutathione peroxidase. We speculate that this suppression of phagocyte-endothelium interactions by oxidized PUFAs may help explain the anti-inflammatory and possible anti-atherogenic effects of diets rich in fish oil. Perhaps more importantly, this modulation of endothelial cell adhesion molecule expression by oxidized lipids may represent a natural mechanism whereby inflammation-mediated oxidation of endothelial PUFAs may retard ingress of phagocytes and thereby prevent unrestrained phlogistic responses.

Animals↗