Biomedical subjects

G N Antonakopoulos

Publications and source records attributed to G N Antonakopoulos.

At least 19 recordsLinked to original sources

PubMed2002

A primary tumour of the oesophagus with both melanocytic and schwannian differentiation. Melanocytic schwannoma or malignant melanoma?

A 76 year old white woman presented with a four month history of dysphagia and weight loss. Clinical, radiological, and endoscopic examination revealed a pigmented mass in the lower third of the oesophagus. The preoperative diagnosis, including biopsy examination, was that of malignant melanoma. Following oesophageal resection, the mass was found to be a localised, relatively superficial tumour with light, electron microscopic, and immunohistochemical features common to both Schwann cells and melanocytes. The patient survived 46 months after surgery and died of a stroke, with no evidence of tumour recurrence. The tumour is presented as a case of melanocytic schwannoma, with unique features when compared with oesophageal melanotic schwannomas and malignant melanomas described in the literature. The differential diagnosis is discussed and an origin from a common precursor cell of neural crest origin is postulated.

Aged↗

PubMed1998

A case of systemic pseudo-pseudoxanthoma elasticum with diverse symptomatology caused by long-term penicillamine use.

A 47 year old man presented with a two year history of increasing cervical dysphagia, dyspnoea, and cutaneous signs. He had been diagnosed 27 years previously with Wilson's disease and was treated with penicillamine (1.5 g daily). Systemic abnormality of elastic fibres was confirmed by light and electron microscopy following biopsy of skin, lung, oesophageal muscle, gum, pharyngeal tissue, and cervical connective tissue. Dysphagia was relieved by cricopharyngeal myotomy. Substitution of trientene dihydrochloride for penicillamine relieved cutaneous and systemic manifestations. This is possibly the first case demonstrating an association between prolonged penicillamine use and biopsy proved systemic pseudo-pseudoxanthoma elasticum. The presenting symptoms may have resulted from the abnormal numbers and properties of elastic fibres, and the changes were caused by penicillamine use, rather than by idiopathic, inherited pseudoxanthoma elasticum.

Chelating Agents↗

PubMed1994

Effects of chemotherapy on ultrastructure of oesophageal squamous cell carcinoma.

Seven oesophageal squamous carcinomas, treated with pre-operative chemotherapy (mitomycin-C, ifosfamide and cisplatin-MIC), with a course finishing 21 days prior to resection, were examined by electronmicroscopy. In one treated case detailed light microscopy failed to reveal any tumour. Five of the remaining six tumours showed cytotoxic damage in that apoptosis and unusual necrotic changes were observed in almost all the neoplastic cells. These features were not seen in untreated cases. In four additional cases, who received one pulse of MIC followed by biopsy or resection within 3-6 days, apoptotic changes were very pronounced and extensive and most neoplastic cells presented unusual degeneration with characteristic derangement of the cytoskeleton, destruction of organelles and accumulation of glycogen. The ultrastructural appearance of 18 untreated resected oesophageal squamous carcinomas was studied for comparison with the treated tumours. The study has demonstrated ultrastructural changes resulting from chemotherapy. Results suggest that the regimen is more effective against squamous carcinomas than against adenocarcinomas of the oesophagus, as judged by comparison with the results of a previous study.

Adult↗

PubMed1992

The ultrastructure of oesophageal carcinomas: multidirectional differentiation. A transmission electron microscopic study of 43 cases.

Forty-three oesophageal carcinomas, comprising 15 squamous cell carcinomas, 22 adenocarcinomas, 5 small cell carcinomas, and 1 adenosquamous carcinoma, were examined by transmission electron microscopy. The ultrastructural features of each tumour type are detailed. Multi-directional differentiation (heterogeneity) was observed in 11 cases: 5 squamous cell carcinomas with focal glandular features; 4 adenocarcinomas with focal squamous features; and 2 small cell carcinomas, one with glandular and the other with squamous features. Abnormal distributions of desmosomes in squamous cell carcinomas and of polarity of tumour cells in adenocarcinomas are described.

Adenocarcinoma↗

PubMed1992

Effects of chemotherapy on ultrastructure of oesophageal adenocarcinoma.

AIMS: To compare and contrast the ultrastructural appearance of resected oesophageal adenocarcinomas treated with preoperative chemotherapy with that of non-treated resected controls; and to determine the usefulness of this method in the assessment of the effectiveness of the chemotherapeutic regimen. METHODS: Ten resected oesophageal adenocarcinomas treated with preoperative chemotherapy--mitomycin-C, ifosfamide, and cisplatin (MIC)--were examined by transmission electron microscopy and their appearance compared with that of 13 concurrent untreated resected oesophageal adenocarcinomas. RESULTS: The treated adenocarcinomas showed cytotoxic damage although complete tumour eradication was not achieved. In all 10 treated cases a variable proportion of the neoplastic cells showed unusual degenerative and necrotic changes not seen in untreated cases. In the most affected carcinomas the stroma contained increased numbers of inflammatory cells. CONCLUSIONS: This ultrastructural method is useful for the assessment of the in vivo effect of MIC.

Adenocarcinoma↗

PubMed1991

Host-parasite interface of the urinary bladder-inhabiting nematode Trichosomoides crassicauda: changes induced in the urothelium of infected rats.

The urinary bladders of rats infected with Trichosomoides crassicauda were studied by light, scanning and transmission electron microscopy. The bladder epithelium of infected rats showed a diffuse, mild, flat hyperplasia, four to six cells thick. The anterior parts of adult female worms were embedded in tunnels within the hyperplastic epithelium with the posterior portions of the parasites lying free in the bladder lumen. The hyperplastic epithelial cells forming the inner layer of the tunnel wall, adjacent to the parasite, showed degenerative changes. These cells contained single or multiple pycnotic nuclei. Their cytoplasm was fibro-granular in appearance, with few distinct organelles, and the luminal surfaces of the cells were not limited by plasma membranes. Small numbers of granular cells, similar in appearance to mast cells, were seen in, and possibly crossing, the epithelium. There was no infection-related increase in the number or type of inflammatory cells in the lamina propria. Questions of interest emerging from this study relate to the nutrition of an adult nematode occupying an intra-epithelial location, and the absence of a significant chronic inflammatory response to the mature worm. It is suggested that the avascular hyperplastic epithelium of the bladder is an immunologically 'protected site' for the mature female T. crassicauda.

Animals↗

PubMed1991

Intestinal graft versus host disease.

An ileocolectomy specimen was examined from a patient with graft versus host disease (GvHD). In addition to the characteristic histological features of this condition, both the small and the large intestine showed extensive destruction of mucosal tissue with survival of clusters of enterochromaffin cells. This appearance has previously been described only in the large bowel. Endocrine cells seem to be less vulnerable to the effects of GvHD than epithelial cells, resulting in their being spared, which is not seen in other types of crypt destruction.

Adult↗

PubMed1989

The fine structure of the human fetal urinary bladder. Development and maturation. A light, transmission and scanning electron microscopic study.

The urinary bladders of 27 human fetuses, aged 7 weeks to full term, were studied by light, transmission and scanning electron microscopy to establish the sequence of events in the development and maturation of the organ during fetal life. In the early specimens, 7-12 weeks old, the urinary bladder was lined by a bilayered, cuboidal and glycogen-rich epithelium. During the 13-17th weeks the epithelium thickened, a third layer developed and by light microscopy it now resembled urothelium. By 21 weeks this had evolved into a 3-4 layer thick epithelium with typical ultrastructural urothelial characteristics. Smooth muscle cells emerged from the condensed mesenchyme of the bladder wall by the 12th week of gestation, initially in the cephalic part of the organ but spreading within a week into the caudal end. Our findings indicate that the human fetal bladder undergoes a series of vital developmental changes during 13-21 weeks of gestation finally acquiring the typical urothelial lining and a well-developed muscular coat.

Embryonic and Fetal Development↗

PubMed1989

Intraepithelial lumina in urothelial bladder neoplasms. A histochemical, immunohistochemical and electron microscopy study.

Intraepithelial lumina observed in 12 urothelial bladder neoplasms were studied histochemically, immunohistochemically and ultrastructurally. Both intercellular and intracytoplasmic lumina could be demonstrated showing an alcianophilic margin and containing non-sulphated acid mucins. The presence of secretory component (SC) was identified in neoplastic urothelial cells around or adjacent to intercellular lumina as well as in cells with intracytoplasmic lumina. The cells surrounding intercellular lumina revealed ultrastructurally tight junctions, microvilli and a prominent glycocalyx while cellular remnants were found quite often within the lumen. As similar histochemical, immunohistochemical and ultrastructural characteristics are also expressed in surface umbrella cells of normal urothelium it is suggested that a focal differentiation of neoplastic urothelial cells towards surface umbrella-like cells takes place and that this process is intimately related to the formation of lumina.

Carcinoma↗

PubMed1988

Scanning electron microscopy of the upper urinary tract in transitional cell carcinoma of the renal pelvis.

Three nephrectomy specimens with transitional cell carcinoma (TCC) of the renal pelvis were thoroughly examined by both light and scanning electron microscopy. The tumours as well as the urothelium of the upper urinary tract were studied. In all three cases, extensive areas of the urothelium, even in places remote from the tumours, were found by scanning electron microscopy (SEM) to be covered by pleomorphic microvilli. This suggests that there is a widespread failure of differentiation of the urothelium to a much greater extent than can be appreciated by conventional light microscopy.

Adult↗

PubMed1988

Xanthogranulomatous pyelonephritis. A reappraisal and immunohistochemical study.

The clinicopathologic features of 17 patients with xanthogranulomatous pyelonephritis are described, together with results on a number of histochemical and immunohistochemical techniques that were used to demonstrate the variety of cells involved. Based on our clinicopathologic data and review of the literature, we believe that xanthogranulomatous pyelonephritis should be regarded as a destructive, and, at times, tumefactive inflammatory process that may complicate chronic pyelonephritis. The initiation of this process remains an enigma. However, there appears to be three main features that are associated with xanthogranulomatous pyelonephritis: pelvicalyceal obstruction, ulceration of the pelvicalyceal urothelium, and bacterial infection.

Adult↗

PubMed1987

Curschmann's spirals in sputum: histochemical evidence of bronchial gland ductal origin.

Curschmann's spirals from 30 patients suffering from chronic bronchitis were examined histochemically by periodic acid-Schiff (PAS), Alcian blue (AB), PAS-AB, high-iron diamine (HID), and HID-AB stains. Their central core and fibrillar component were found to be rich in neutral mucins and in sulfated and nonsulfated acid mucins, while their outer mantle was rich in neutral and nonsulfated acid mucins only. Curschmann's spirals consist of mucus of high viscosity. Histochemical and morphological evidence suggests that, in addition to their origin in the lumen of smaller bronchi and bronchioles, they are also formed in the ducts of the seromucous bronchial glands.

Adult↗

PubMed1987

Intestinal spirochaetosis. Light and electron microscopic study.

24 cases of colon spirochaetosis have been studied by light and electron microscopy. This condition, although rarely diagnosed because of the absence of special clinical symptoms, seems to be a rather frequent histologic finding with marked variation in its geographical incidence. In our material the incidence of spirochaetosis was 16.5%, almost double than in Great Britain.

Adult↗

PubMed1987

Production of beta-human chorionic gonadotropin by prostatic adenocarcinoma and transitional cell carcinoma of the upper urinary tract.

Ectopic production and secretion of hormones by a wide variety of tumours has been known for many years. Recently human chorionic gonadotropin (HCG) production and/or secretion have been noted in 15 cases with prostatic adenocarcinoma (Fukutani et al. 1983; Papapetrou et al. 1980: Broder et al. 1977; Menon & Stefani 1980; McManus et al. 1976) and in two with upper urinary tract transitional cell carcinoma (Fukutani et al. 1983; McManus et al. 1976). In this study we utilised the indirect immunoperoxidate technique to demonstrate beta-HCG production in prostatic adenocarcinoma and upper urinary tract urothelial tumours. Of 100 cases of prostatic adenocarcinoma beta-HCG production was demonstrated in nine cases, eight of which were poorly differentiated, and of 14 urothelial tumours of the upper urinary tract beta-HCG production was present in two high grade transitional cell carcinomas.

Adenocarcinoma↗

PubMed1985

Spindle cell carcinoma (pseudosarcoma) of the anus: a light, electron microscopic and immunocytochemical study of a case.

We report a case of polypoid spindle cell squamous carcinoma (pseudosarcoma) occurring in the anal canal. Electron microscopic findings and the demonstration of keratin by an immunoperoxidase method, gave clear cut evidence of the epithelial nature of the sarcomatoid cells forming this tumour. To our knowledge, this is the first reported case in the literature.

Anus Neoplasms↗

PubMed1985

Widespread mucous metaplasia of the urinary bladder with nephrogenic adenoma.

We describe widespread metaplastic changes observed in nonexstrophic urinary bladder mucosa in a 32-year-old man. Extensive areas of the luminal surface were covered by two types of metaplastic epithelium. One type was bilayered while the other was single layered with columnar cells of varying electron density as well as mucus-secreting cells. An area of adenomatoid metaplasia was also observed.

Adenoma↗

PubMed1985

Idiopathic hydronephrosis. Light microscopic features and pathogenesis.

A histological study of surgical specimens of idiopathic hydronephrosis demonstrated an abnormal muscle arrangement at the ureteropelvic junction in 18 of 26 cases. We believe this abnormality to be the cause in these cases. At this junction, the muscle bundles, instead of displaying the normal interwoven (braided) pattern, are arranged into an outer circular and an inner longitudinal layer. This abnormal muscle arrangement can be attributed to local failure of the physiological uncoiling during growth and development.

Adolescent↗

PubMed1984

The subcellular basis of damage to the human urinary bladder induced by irradiation.

The effects of x-irradiation on the subcellular structure of the human urinary bladder were investigated by electron microscopic examination of biopsies taken during check cystoscopies from 25 patients between 1 month and 22 years after completion of a course of therapeutic radiation. All tissues of the bladder wall were damaged to some extent by the treatment. In the urothelium this was reflected by the development of more than the usual numbers of lysosomes and autophagic vacuoles in all cell layers. In the bladder wall, large often binucleate or multinucleate fibroblasts were prominent and persistent in all specimens and were associated with the development of progressive fibrosis. The vasculature and the muscle coats of the bladder wall were also damaged. In the blood vessels many endothelial cells were oedematous or necrotic and some intravascular coagulation was also observed. Smooth muscle cells became oedematous soon after irradiation, and after longer time intervals there was focal death and loss of individual muscle cells. The observed degeneration and extensive necrosis of the bladder wall, which involved severe destruction and disorganization of the muscular layers, is sufficient to explain the clinical sequelae of bladder irradiation, namely loss of elasticity, reduced capacity and incomplete micturition with residual urine.

Adult↗