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Biomedical subjects

S Satchidanand

Publications and source records attributed to S Satchidanand.

At least 19 recordsLinked to original sources

The relationship between smoking exposure and p53 overexpression in colorectal cancer.

Although epidemiological studies of the relationship between cigarette smoking and colorectal cancer risk have been equivocal, a positive association is consistently found for colorectal adenoma development. We performed an epidemiological study to determine whether p53 protein overexpression, in tumours obtained at the time of resection, is associated with cigarette exposure in colorectal cancer. A total of 163 colorectal cancer cases and 326 healthy controls responded to a standardised questionnaire on colorectal cancer risk factors including detailed information on their history of cigarette smoking. All patients' tumours were analysed immunohistochemically for p53 overexpression using an avidin-biotin immunoperoxidase procedure and polyclonal anti-p53 antibody CM1. Comparison of colorectal cases with controls revealed an elevated risk for ex-smokers (OR = 1.34, 95% CI 0.85-2.12) and current smokers (OR = 1.13, 95% CI 0.63-2.02) when compared with non-smokers. No dose-response relationship was found for total pack-years of smoking (trend test: P = 0.19). However, a trend for total pack-years of smoking was found when p53-positive cases were compared with p53-negative cases suggesting aetiological, heterogeneity (trend test: P = 0.06). Estimating the individual relative risk of developing a p53-positive tumour relative to controls showed no associations for smoking status or total pack-years of smoking. However, when p53-negative cases were compared with controls, an elevated risk was found for ex-smokers (OR = 1.84, 95% CI 1.00-3.37) and current years of smoking (trend test: P = 0.03). Colorectal tumours developing through p53-positive dependent pathways were not associated with smoking exposure. A significant increase in risk was observed for the p53-negative independent pathway with smoking. p53 overexpression appears to be associated with smoking exposure in colorectal cancer.

Adult↗

Familial and nutritional risk factors for p53 overexpression in colorectal cancer.

Although familial and dietary factors are recognized as important risk determinants for colorectal tumorigenesis, the specific causes of colorectal cancer remain unclear. Studies of p53 genetic alterations have provided clues concerning the etiology of many cancers. This study was designed to determine whether overexpression of the p53 protein is associated with familial and dietary risk factors. Epidemiological data were obtained from 163 colorectal cancer cases and 326 healthy controls. Tumors of all patients were analyzed immunohistochemically for p53 overexpression using an avidin-biotin immunoperoxidase procedure and polyclonal anti-p53 antibody CM1. Of patient tumors, 44.8% showed p53 nuclear reactivity. Colorectal cases versus controls were three times more likely to report a family history of colorectal cancer [odds ratio (OR), 3.12; 95% confidence interval (CI), 1.77-5.52]. Only cruciferous vegetables exhibited a significant inverse association (OR, 0.59; 95% CI, 0.34-1.02; trend test, P = 0.03) for the highest versus lowest quartiles. Both meat and beef displayed an elevated increase in risk. When cases with p53 overexpression (p53 positive) were compared with cases without p53 overexpression (p53 negative), etiological heterogeneity was suggested for family history of colorectal cancer (OR, 0.39; 95% CI, 0.16-0.93), cruciferous vegetables (trend test, P = 0.12), and beef consumption (trend test, P = 0.08). To estimate the individual relative risks for p53-dependent and p53-independent pathways, each p53 subtype was compared with controls. Cruciferous vegetables exhibited a significant association (OR, 0.37; 95% CI, 0.17-0.82; trend test, P = 0.03) when p53 positive cases were compared with controls. When p53 negative cases were compared with controls, a significant increase in risk was observed for family history of cancer (OR, 4.46; 95% CI, 2.36-8.43) and beef (OR, 3.17; 95% CI, 1.83-11.28; trend test, P = 0.006). The p53 (positive) dependent pathway was characterized by an inverse association with cruciferous vegetables, and p53-independent tumors were characterized by family history and beef consumption. These data may indicate the significance of linking epidemiology and molecular biology in assessing specific etiological pathways.

Adenocarcinoma↗

Malignant juxtadrenal schwannoma.

We believe we report the first case of malignant juxtadrenal schwannoma. This rare tumor was discovered incidentally in a patient who presented with fever, mental confusion, weight loss, leukocytosis, and elevated erythrocyte sedimentation rate. Preoperative radiographic and endocrine evaluations were suggestive of a nonfunctioning adrenal tumor. Its suprarenal location was unequivocally demonstrated by CT scan, sonography, angiography, and magnetic resonance imaging studies. Angiography revealed that the tumor derived its blood supply from the adrenal and renal vessels. The final diagnosis and its juxtadrenal origin was confirmed by histologic and immunohistochemical studies. A review of the literature on retroperitoneal schwannoma is included.

Adrenal Gland Neoplasms↗

Ultrastructural study of the histogenesis of salivary gland mucoepidermoid carcinoma.

This electronmicroscope study of the histogenesis of mucoepidermoid carcinoma is based on 15 cases from the major and minor salivary glands. Six major cell types were identified: undifferentiated (cuboid) stem cells, intermediate (columnar) cells, serous/mucoid secretory cells, mucus-producing goblet cells, squamous/epidermoid cells and myoepithelium. It is proposed that undifferentiated stem cells serve as pluripotential reserves which give rise to the various cell types seen in mucoepidermoid carcinoma. Reserve cells in the acinar-intercalated duct components of the salivary glands appeared to give rise to the serous/mucoid and myoepithelial cell populations of mucoepidermoid carcinoma. Reserve cells in the proximal ducts system (intra/extralobular striated ducts and excretory ducts) differentiated into myoepithelium, intermediate (columnar) cells, squamous/epidermoid and mucus-producing goblet cell lines. It is proposed that neoplastic reserve cells give rise to different tumor types in the salivary glands. These types result from varying admixtures and arrangements of tumor cells at different stages of their structural and functional cytodifferentiation from reserve cells. It is further proposed that neoplastic reserve cells differentiate along similar cell lines as the embryonic "stem cells" in the development of normal salivary glands.

Adult↗

Histogenesis of adenoid cystic carcinoma of the salivary glands. Light and electronmicroscopic study.

This ultrastructural study, based on 12 cases of adenoid cystic carcinoma of the major and minor salivary glands, was conducted to determine the role and extent of participation of myoepithelial cells in their histogenesis. The tumors were composed of four major cell types; intercalated duct, myoepithelial, secretory, and pluripotential reserve/stem cells. The cellular composition of adenoid cystic carcinoma is similar to that in the "terminal tubule" complex stage of a developing salivary gland except that in the tumor the pluripotential reserve/stem cells differentiate predominantly along the intercalated duct cell line rather than secretory cells as in the acinic cell carcinoma. Furthermore, adenoid cystic carcinoma appears to contain a far greater number of myoepithelial cells than acinic cell carcinomas.

Adult↗

Villous tumors of the duodenum and ampulla of Vater.

Polypoid epithelial tumors of the duodenum and ampulla of Vater are rarely diagnosed preoperatively without wide application of fiberoptic endoscopy. The symptoms are nonspecific. Only a high index of suspicion will lead to early diagnosis. Life-threatening complications and increased incidence of malignant transformations are associated with delayed diagnosis. This paper reviews 11 patients (nine previously unreported) with villous tumor of the ampulla of Vater and two with this neoplasm in the duodenum. It also reviews the important principles of management illustrated by the behavior of the tumors of these 11 patients compared to those of previous reports. For favorable results, all lesions must be excised in toto and evidence of invasive malignancy must lead to aggressive treatment whenever feasible.

Adenoma↗

Light and ultrastructural features of lymphoepithelial lesions of the salivary glands in Mikulicz's disease.

This investigation deals with the histogenesis of the so-called 'epimyoepithelial islands' in Mikulicz's disease of the major salivary glands and is based on light and electron microscopic study in six patients. The 'epimyoepithelial islands' represent collapsed acini prior to their complete involution and disappearance, the intraductal cellular proliferation, stratification and differentiation into luminal and peripheral myoepithelial cells with partial and complete obliteration of their lumina and finally, cord-like proliferation and formation of nests of residual pluripotential cells showing squamous metaplasia and occasional myoepithelial cell differentiation. A pink, homogeneous and hyaline material on light microscopic examination is multilayered and extracellular and is in close association with the basal lamina when viewed with electron microscope.

Adult↗

Histogenesis of acinic cell carcinoma of the major and minor salivary glands. An ultrastructural study.

This study describes the light microscopic, histochemical and electron-microscopic findings of 10 acinic cell carcinomas from the major and minor salivary glands. Ultrastructurally, four cell types were identified: secretory acinar cells, intercalated duct-like cells, pluripotential reserve/stem cells and myoepithelial cells. This cellular composition suggests that the tumours are derived from neoplastic proliferation, cytodifferentiation and functional maturation of pluripotential reserve/stem cells which normally reside at the acinar-intercalated duct junctions and/or in the intercalated ducts proper of adult salivary glands. This study further supports the concept that different salivary gland tumours recapitulate various developmental stages in the normal embryogenesis of the salivary glands.

Aged↗

Clinical advantages of papaverine cardioplegia.

To determine the efficacy of papaverine in improving myocardial protection by causing a uniform distribution of the cardioplegic solution, a prospective study was carried out in 200 consecutive patients undergoing various open heart procedures. Several parameters (creatine kinase MB, electron microscopy of myocardium, perioperative myocardial infarction rate, frequency of postoperative arrhythmias) were monitored and compared with those of a control group which consisted of the previous 200 consecutive patients in whom the same cardioplegic solution was used, but without papaverine. In the papaverine group the operative mortality due to low cardiac output was 0.5% compared to 3%, and the spontaneous recovery of the heart after release of the aortic cross-clamp was 89% compared to 47% in the control group (P less than 0.01). The perioperative myocardial infarction rate was 5% and the incidence of postoperative temporary arrhythmias was also 5% in the papaverine group, while in the control group the perioperative myocardial infarction rate was 10% and the postoperative arrhythmia incidence was 13% (P less than 0.01).

Adolescent↗

Massive bleeding in hypertrophic gastropathy (Menetrier's disease) due to arterio-venous malformation.

A case is reported of hypertrophic gastropathy with characteristic clinical endoscopic and histologic features who presented with massive gastrointestinal hemorrhage due to arterio-venous malformation. Since the course of this disease is not favorable with medical treatment, an operation should be done for patients with life threatening complications and intractable symptoms. Subtotal gastrectomy was found to be satisfactory for patients with limited disease and total gastrectomy for patients with diffuse disease.

Arteries↗

Glycogen-rich tumor of the oral minor salivary glands. A histochemical and ultrastructural study.

A detailed electronmicroscopic study on glycogen-rich tumor is presented. The neoplasm originated from the minor salivary glands on the ventral surface of the tongue. The role of myoepithelial cells in the histogenesis of this lesion is not supported. It is proposed that the tumor arises from "undifferentiated" stem cells analogous to cells in the "end bud" stage of salivary gland morphogenesis. The presence of a large amount of glycogen is secondary to defective carbohydrate metabolism within the tumor cells.

Adenoma↗

Monomorphic adenomas of the parotid glands. Their ultrastructure and histogenesis.

Three cases of monomorphic basal cell adenoma of the parotid glands were studied with light microscopy. In one patient, fresh tissue was available for electron microscopic observations. On the basis of ultrastructural findings it was concluded that myoepithelial cells play little, if any, role in the histogenesis of this lesion. The tumor originates from the undifferentiated stem cells analogous to the cells seen at the "end bud" stage of salivary gland morphogenesis prior to their further cytodifferentiation and functional maturation into secretory and myoepithelial cells. In fully developed salivary glands such undifferentiated stem cells reside as "reserve" cells in the intercalated ductal system.

Adenoma↗

Ultrastructure of monomorphic adenoma (ductal type) of the minor salivary glands.

A monomorphic adenoma (ductal type) of the palatal minor salivary glands is reported. Ultrastructurally, the predominant tumor cells contained zymogenlike dense secretory granules. There was a continuum from tumor cells with little or no secretory granules to ones with increasing numbers of granules. Except for that, the tumor cells shared many of their fine structural features. Histogenetically, the tumor originated from neoplastic proliferations of "undifferentiated" stem cells corresponding to "end-bud" stage of salivary glands embryogenesis. Under neoplastic influences, such cells underwent further cytodifferentiation and functional maturation along the secretory cell lines. In mature salivary glands, such pluripotential cells reside as "reserve" cells in the intercalated ducts.

Adenoma↗

Microinvasive squamous carcinoma of the vulva.

The clinico-pathologic aspects of 15 cases of microinvasive squamous cell carcinoma of the vulva are analyzed and the literature on this subject is reviewed. Three patients in this group and 12.5% of the 279 reported cases, all with 5 mm or less depth of invasion, have had lymph node metastases and/or recurrences or have ultimately died of their disease. The prognostic value of lymphatic/vascular permeation, the degree of cellular anaplasia, the pattern as well as the depth of invasion, all have been alluded to, and the latter is popularized. It is noted, however, that the arbitrarily chosen 3 or 5 mm depth of invasion alone does not allow for consistent identification of individuals with a negligible risk for groin lymph node metastasis. There is indeed documentation of nodal metastases in 20 of 178 (11%) of the reported cases with 1-3.5 mm invasion. It is suggested that the level of invasion, as determined by Clark's classification, which provides a histologic reference point, may correlate better with the incidence of groin nodal metastasis, and its use may allow for individualized therapy and eventually aid in identifying cases of microinvasive carcinoma of the vulva that could safely be treated without lymphadenectomy.

Adult↗

Myoepithelial cell adenoma of the parotid gland: a light and ultrastructural study.

Light, histochemical, and ultrastructural features of a myoepithelial cell adenoma of the parotid gland are described. Ultrastructurally, the neoplasm was almost entirely composed of myoepithelium. The spindle-shaped myoepithelial cells and their processes were filled with longitudinally oriented myofilaments with characteristic densities along their course and marginal attachment plaques. The tumor cells were interconnected by desmosomes. The role of myoepithelium in the genesis of some salivary gland tumors is discussed.

Adenoma↗

Colonic ischemic necrosis following therapeutic embolization.

Transcatheter embolization of the middle colic artery for diverticular bleeding was followed by ischemic necrosis in the transverse colon at the site of previous anastomosis and stricture formation. This is a potential complication of intra-arterial embolization for colonic bleeding.

Aged↗