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Biomedical subjects

P Dervan

Publications and source records attributed to P Dervan.

At least 37 records · Page 2Linked to original sources
PubMed1993

Labial melanotic macule: a clinical, histopathologic, and ultrastructural study.

BACKGROUND: The labial melanotic macule (LMM) is a recently described pigmentary anomaly that may simulate malignant melanoma. OBJECTIVE: Our purpose was to define the LMM clinically, histologically, and immunohistochemically in a large group of patients. METHODS: We describe the clinical features of 36 LMMs in 29 patients (aged from 4 to 79 years, 4 male, 25 female) seen during the past 4 years. Histopathologic findings in 21 of these patients are discussed. Seventeen lesions were immunostained with HMB-45 monoclonal antibody, and electron microscopy was performed on eight lesions. RESULTS: The majority of patients were women and had solitary lesions on the lower lip with the mean age of onset of 30 years. Histologically prominent basilar hyperpigmentation accentuated at the tips of the rete ridges was present without atypia or nevoid formation. Immunohistochemical studies showed that all intralesional melanocytes were HMB-45 negative, supporting their benign nature. Ultrastructurally, numerous stage III and IV melanosomes clustered within basal keratinocytes and papillary dermal melanophages were found. CONCLUSION: The LMM is a clinically and histologically distinctive benign pigmentary anomaly.

Adolescent↗
PubMed1993

Pancreatic atrophy: a new model using serial intra-peritoneal injections of L-arginine.

No simple rat model for chronic pancreatitis exists at present. A single dose of arginine has recently been shown to induce acute pancreatitis in rats. This study was designed to assess whether serial injections of arginine would induce reproducible chronic pancreatic damage. Forty rats received an intra-peritoneal injection of 500 mg per 100 g body weight of L-arginine followed by three injections of 250 mg per 100 g over 10 days. The rats were killed 24 h after each injection and at intervals of up to 6 months. Serum amylase levels were increased in the acute phase only. Examination of the pancreas at 24 h showed a severe oedematous pancreatitis. By day 5 there was up to 90% acinar destruction with adipose tissue replacement, although ductal, vascular, and islet cells appeared undamaged. These changes were present 6 months after injection. This is proposed as a new, simple, and reproducible method of inducing chronic pancreatic damage in the rat.

Animals↗
PubMed1992

Morphological changes and alterations in regional intrarenal blood flow induced by graded renal ischemia.

A model of renal ischemia was used to study morphological changes and alterations in intrarenal blood flow. Renal artery blood flow was reduced from 120 to 20 ml./minute (normal 172 +/- 14) for 3 weeks. Morphological changes were assessed histologically, and by electronmicroscopy. Intrarenal blood flow was determined using microspheres. Flow rates less than 80 ml./minute resulted in a progressive loss of renal volume with arterial thrombosis and renal infarction at 20 ml./minute. Histological changes included loss of glomerular volume, tubular dilatation (60 ml./minute), tubular cast formation (50 ml./minute) tubular atrophy, interstitial fibrosis, arteriolar thickening (40 ml./minute) and glomerular hyalinization (30 ml./minute). Electronmicroscopy changes at 60 ml./minute (loss of glomerular microvasculature, unfolding of glomerular vascular tuft, appearance of blind ending vessels) progressed to disruption of glomerular architecture noted at 30 ml./minute. Narrowing of medullary blood vessels (60 ml./minute) and neovascularisation (40 ml./minute) was observed. Progressive ischemia decreased medullary, inner cortical and outer cortical blood flow (5.9 to 2.1 ml./minute/gm.) p less than 0.01, with a compensatory increase to the opposite kidney.

Animals↗
PubMed1992

Generalized elastosis perforans serpiginosa in Down's syndrome.

Elastosis perforans serpiginosa is a rare disorder of epidermal perforation characterized by the extrusion of dermal elastic tissue through the epidermis. Its aetiology is unknown, but there is histological and biochemical evidence of an abnormality of elastic tissue. Three forms of elastosis perforans serpiginosa exist. It may be either idiopathic, iatrogenic, or, in approximately one quarter of cases, associated with certain genetically determined disorders of connective tissue. Cutaneous lesions appear between the ages of 6 and 20 years, and persist for 6 months to 5 years. They may be confined to one anatomic area, or less frequently are disseminated. We review the case of a 28-year-old woman with recent onset of unusually extensive elastosis perforans serpiginosa with co-existing Down's syndrome and (secondary) sclerosing cholangitis.

Adult↗
PubMed1992

Reactivity of P-glycoprotein monoclonal antibodies in childhood cancers.

P-Glycoprotein (P-gp), the product of the mdr-1 gene, is implicated in the development of chemoresistance in a variety of, mostly adult, cancers. Its role in paediatric tumours, most of which are non-epithelial in origin, has yet to be fully elucidated. A study was undertaken to investigate reactivity of two P-gp monoclonal antibodies (MAbs), JBS-1 and MRK16, recognising cytoplasmic and surface epitopes, respectively, of the P-gp molecule, in a variety of newly diagnosed and relapsed childhood cancers. P-gp was not expressed in any of 36 tumours examined (neuroblastoma 13, nephroblastoma 12, rhabdomyosarcoma 6, lymphoma 3, teratoma 1, Ewings 1), 14 of whom had chemoresistant disease. Reactivity to both MAbs was also investigated in patients with acute leukaemia. Out of 10 diagnostic acute lymphoblastic leukaemia (ALL) samples, a positive reaction with JSB-1 was observed in 1 patient who failed to remit on standard induction therapy and in 3 of 6 patients in ALL relapse, only 1 of whom showed low grade positivity with MRK16. Both MAbs reacted positively in 1 patient with acute non-lymphocytic leukaemia (ANLL) at diagnosis who achieved remission with teniposide and cytosine arabinoside, but relapsed 7 months later and was again positive with both Mabs. JSB-1 also showed varying degrees of positivity in 4 out of 4 other patients in ANLL relapse. It would therefore appear that P-gp is unlikely to mediate chemoresistance in most solid tumours of childhood, but may well play a major role in the development of chemoresistance in acute leukaemia.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1992

The prognostic value of nucleolar organiser regions in colorectal cancer: a 5-year follow-up study.

Nucleolar organiser regions (AgNORs) are loops of ribosomal DNA which reflect the cellular activity or malignant potential of the cell and are identified by a specific staining technique. The purpose of this study was to assess the prognostic value of AgNORs in colorectal cancer and to compare it with other accepted prognostic methods. We studied 164 patients who were surgically staged for colorectal cancer and who had complete follow-up data available for 5 years. Using a highly specific silver staining and counting technique each patient was given an AgNOR score. There were 5 Dukes' C tumours, 108 were Dukes' B and 5 were Dukes' A. No cancer deaths occurred in patients with Dukes' A tumours. The incidence of well-differentiated, moderately-differentiated and poorly-differentiated tumours was 37.2%, 53.7% and 9.1%, respectively. Non-survivors had significantly higher AgNOR scores compared with survivors (mean value +/- SD, 14.2 +/- 0.9 vs 8.2 +/- 0.6, P less than 0.0001). In a regression analysis model AgNOR score was the most significant individual variable for predicting survival (chi 2 = 15, P less than 0.01) when compared with Dukes' classification, histological grade, tumour depth or vascular invasion.

Adult↗
PubMed1991

Necrobiosis lipoidica and sarcoidosis.

We report the case of a female patient with necrobiosis lipoidica of the lower legs and coexistent systemic and cutaneous sarcoidosis. We review the six previously reported patients with coexisting necrobiosis lipoidica and sarcoidosis. The associations between the granulomatous disorders of the skin, especially necrobiosis lipoidica, sarcoidosis and granuloma annulare, are discussed. The common pathogenetic features of these disorders are reviewed.

Female↗
PubMed1991

Imaging of intramedullary tumour spread in osteosarcoma. A comparison of techniques.

The level of bone resection for osteosarcoma depends on the pre-operative evaluation of the extent of intramedullary tumour. We compared the accuracy of magnetic resonance imaging (MRI), computerised tomography (CT), and isotope bone scanning with the actual extent of the tumour in the resected specimens from 34 patients with primary osteosarcoma of a long bone. The extent of medullary tumour was defined accurately in 23 of 24 MRI scans (96%) and 24 of 32 CT scans (75%). A flexion contracture of a joint close to the tumour was an important cause for inaccurate measurements from both MRI and CT scans. Isotope bone scanning was inaccurate: its role is now confined to detecting skeletal metastases and skip lesions.

Adolescent↗
PubMed1990

The skeletal framework of human kidney and renal cell carcinoma. A scanning electron microscopic study.

The three dimensional architecture of the connective tissue framework of normal human kidney and three renal cell carcinomas was studied. A sodium hydroxide maceration technique was used to remove the cellular elements thus exposing the underlying connective tissue structures. The collagen fibrillar network was visualized using the scanning electron microscope. In normal kidney the fibres were fine, and smooth, and corresponded to the shapes of the original parenchymal constituents. The fibres of the kidney tumours were coarse in nature and irregularly distributed. The technique provides a rapid method for studying connective tissue fibres in normal and diseased tissue. The three dimensional architecture thus exposed enhances our knowledge of tumour stroma.

Carcinoma, Renal Cell↗
PubMed1990

Granulomatous hepatitis in secondary syphilis.

An unusual case of a well-documented granulomatous hepatitis in secondary syphilis in a 47-year-old male is presented. This hepatic pathology in secondary syphilis is summarised, and a review of the literature regarding syphilitic granulomatous hepatitis presented.

Granuloma↗
PubMed1990

Contractions to 5-hydroxytryptamine in human coronary artery and human saphenous vein.

Isometric contractions were obtained to 5-hydroxytryptamine receptor agonists in human saphenous vein and human coronary artery. Based on the interaction with the 5-HT2 receptor antagonist ketanserin, both 5-HT1 and 5-HT2 receptors are involved in contractions of human saphenous vein, but the predominant subtype involved in contractions of human coronary artery is the 5-HT1 receptor.

Coronary Vessels↗
PubMed1989

Three-dimensional morphological study of the pancreatic microvasculature in caerulein-induced experimental pancreatitis.

A morphological study of the pancreatic microvasculature in experimental pancreatitis was performed in dogs, using three-dimensional scanning electron microscopy vascular casting and transmission electron microscopy. Animals with pancreatitis were characterized by a marked reduction in the number of capillaries outlined by the cast and by distortion of those that were outlined, with irregularity of the capillary lumen, abruptly terminating capillary buds and leakage of the cast material through the capillary membrane. The study provides convincing morphological evidence that one of the earliest changes in acute pancreatitis is distortion of the capillary circulation.

Acute Disease↗
PubMed1989

Prognostic value of nucleolar organizer regions and ploidy values in advanced colorectal cancer.

The prognostic value of nucleolar organizer regions and ploidy status in patients with Dukes' C colorectal cancer was determined. In addition, nucleolar organizer regions and ploidy status were compared with the established prognostic indices age, sex, tumour location and degree of histological differentiation. Fifty-one patients (27 men, 24 women) aged 35-81 years (median 64.8 years) were studied. Five years after presentation, 16 patients were alive and well. Survivors had significantly lower nucleolar organizer region counts (median value and range) in primary tumours 12 (8-15) and lymph node metastases 11 (8-15) than non-survivors 17 (14-25) and 18 (13-25) respectively (P less than 0.05). Fewer survivors had aneuploid tumours than non-survivors: four survivors compared with 17 non-survivors. In a regression analysis model, nucleolar organizer regions were the most important individual variable for predicting survival (chi2 = 15, P less than 0.01) while ploidy values (chi2 = 6, P less than 0.2) were equivalent to histological differentiation.

Adult↗
PubMed1989

Optimizing the immunohistochemical signal from the transferrin receptor in liver tissue.

Cellular expression of the transferrin receptor is determined by the proliferative state and iron requirements of the cell. Previous immunohistochemical studies using a number of anti-(transferrin receptor) monoclonal antibodies confirmed the biochemical evidence that hepatocytes express the receptor, although the distribution shown was patchy with only a small number of cells showing positive staining. In the present study, a number of techniques have been compared to optimize detection of the immunohistochemical signal from the transferrin receptor in human liver tissue. Using an alkaline phosphatase detection system, widespread expression of this receptor with both cytoplasmic and membrane staining was found in all parenchymal and non-parenchymal cells.

Alkaline Phosphatase↗