Histopathological features and grading in rhabdomyosarcomas of childhood

Rhabdomyosarcoma represents a large group of soft tissue sarcomas displaying heterogeneous histopathological features. In addition to their histopathological classification, the variable expression of a number of histopathological features may contribute to the heterogeneity and may be related to prognosis. Tissue sections of 113 well-documented, protocol-treated patients with long term follow-up (mean 6 years) were analysed by a panel of four paediatric pathologists. The following features were assessed: presence of rhabdomyoblasts, degree of maturation of rhabdomyoblasts, heterogeneous maturation patterns, mitotic activity, tumour necrosis, myxoid component, and septa. A scoring system was allocated to each index. High degree of maturation (amount of cytoplasm greater than surface area of the nucleus), absence of tumour necrosis (< 10% of tumour surface), and absence of septa (< 10% of tumour surface) significantly correlated with a favourable clinical course. Reproducibility in the assessment of these three features was good: mean κ varying from 0.53 to 0.64. A rhabdomyosarcoma score function for survival was defined by: (-0.27 x degree of maturation score) + (0.007 x percentage septated area) + (0.031 x percentage tumour necrosis). Based on the score a two-grade system was elaborated, i.e. grade I (score < -0.20) v. grade II (score < -0.20). Rhabdomyosarcoma grade appeared to be the best factor in predicting patients survival: 69% long-term survival in patients with grade I v. 33% in patients with grade II (P= 0.0001). Moreover, this grading system was shown to have discriminative power within the group of patients with embryonal rhabdomyosarcoma: patients with a grade I tumour fared significantly better than those with a grade II tumour (63%v. 41% long-term survival, P= 0.03). This study, therefore, demonstrated the prognostic value of this grading system and its useful application within the group of patients with embryonal rhabdomyosarcomas.     

The relevance of morphometry in the differential diagnosis of cutaneous T cell lymphomas

Morphometric analysis of lymphoid cells in the skin was used to differentiate between cutaneous T cell lymphomas (CTCL), i.e. mycosis fungoides (MF) and Sézary syndrome (SS), and chronic benign skin diseases. In electronmicrographs of the skin lesions from twenty patients with CTCL (group I), fourteen patients with chronic benign skin diseases (group II) and twenty-nine patients suspected of CTCL (group III), the degree of nuclear indentation of lymphoid cells, expressed as the nuclear contour index (NCI), was measured. Analysis of the NCI histograms of the infiltrating cells of group I and group II permitted us to derive classification criteria for allocating all patients correctly with a high probability (≥95%) in the appropriate group. Only one case was classified with a low probability (71%). The classification criteria are based on the presence of cerebriform mononuclear cells (CMC) with highly indented nuclei (NCI≥11·5) and the frequency distribution of CMC in the skin infiltrates expressed as the 25th and the 70th percentiles of the NCI histograms (P25 + P70). When these criteria were tested on twenty-nine patients suspected of CTCL, twenty cases were classified as malignant, nine as benign. During the follow-up period, out of the twenty patients classified as malignant, seventeen patients appeared to have or develop MF, whereas two patients had lymphomatoid papulosis and one patient is still suspected of MF. Of the nine patients classified as benign, eight patients were proven to have benign skin diseases whereas one developed MF in the follow-up period of up to 4 years. The classification results based on morphometry proved to be more sensitive than those based on DNA cytophotometry. It is concluded that morphometric analysis of lymphoid cells in the skin is of diagnostic relevance in the differential diagnosis of CTCL.     

Observations of the bone activity adjacent to unloaded dental implants coated with Polyactive® or HA

Summary In addition to bone-bonding bioma-terials such as calcium phosphate ceramics and Bioglass/glass ceramics, an elastomeric poly(ethylene oxide) poly(butylene terephthalate) (PEO/PBT) segmented block co-polymer (Polyactive®) was recently introduced. In contrast to ceramic bioma-terials, Polyactive® is a flexible material. In a previous three-dimensional finite element analysis study, it was stated that application of a flexible Polyactive® coating simulates the function of the periodontal ligament. The topic of this investigation was to compare the bone-bonding capacity of Polyactive®-coated titanium implants with hydroxylapatite (HA) coated implants. The implants were inserted bilaterally in the edentulous part of the mandibular bone of 12 goats. After 3 weeks, the implants were in close contact with the cortical bone, but no cortical bone reaction or remodelling was observed. After 9 weeks, an extensive bone reaction was seen around the HA and Polyactive®-coated implants and contact was frequently encountered between newly formed bone and the implants. Within the surface of the Polyactive® coating, a considerable amount of calcification was present. After 25 weeks, cortical remodelling was still apparent. A striking finding was the apparent association between osteon formation and calcification within the surface of the Polyactive® layer. Back-scatter analysis of the non-decalcified Polyactive® bone interface showed the presence of a calcium phosphate layer in the implant material that apparently formed a continuity with the mineral matrix of bone, suggesting bone-bonding. In general, it was observed that the bone reactions to HA and Polyactive® were comparable. A swelling of the coating, just beneath the cortical layer (champagne-cork effect) was often seen. This increase in volume, caused by water uptake, might result in a more intimate initial bone/Polyactive® contact, as compared with other implant materials.     

Glycaemic Control,Smoking Habits and Diabetes Duration Affect the Extrinsic Fibrinolytic System in Type I Diabetic Patients but Microangiopathy Does Not

ABSTRACT The fibrinolytic system was studied in 43 type I diabetic patients with long duration of the disease, with or without evidence of microangiopathy, and in 26 control subjects. There were positive and independent correlations between tissue plasminogen activator (tPA) activity after venous occlusion and HbA_lc, and between triglycerides and plasminogen activator inhibitor (PAI-1) and tPA antigen concentrations before and after venous occlusion. The tPA activities both at rest and after venous occlusion were higher in the patients. There were no differences with regard to sex, hypertension or nephropathy for the levels of fibrinolytic variables in these patients. Subjects with retinopathy did not differ from those without retinopathy. Diabetes duration showed a significant negative association with tPA activity in multivariate regression analysis. Tobacco-smoking diabetics, as compared to non-smoking, had an increased tPA antigen release at venous occlusion, but also higher PAI-1 levels and reduced specific activity of the tPA protein. When assessed with the new specific assays now available, the fibrinolytic parameters appear to be specific indicators of endothelial dysfunction related to smoking and to degree of glycaemic control in type I diabetic subjects.     

MECHANISMS UNDERLYING THE PROLONGED DURATION OF ACTION OF MUSCLE RELAXANTS CAUSED BY EXTRAHEPATIC CHOLESTASIS

The neuromuscular blocking effects of Org 6368 and Org NC 45were studied in rats with experimental cholestasis and in controls.The effect of Org NC 45 during infusion of taurocholate wasinvestigated. In cholestaic rats we observed a three-fold increaseof the duration of action of Org 6368 and Org NC 45. The samewas observed for Org NC 45 with taurocholate. In the rat phrenicnerve-hemidiaphragm preparation taurocholate potentiated theneuromuscular blockade of Org 6368, pancuronium and gallamine,but not Org NC 45. Increased bile salt concentrations causedstrong inhibition of hepatic uptake and biliary excretion ofOrg 6368 and tubocurarine in isolated perfused livers. Taurocholateand glycocholate were more potent than cholate and chenodeoxycholate.Cholestatic livers exhibited a clearance of Org 6368 which was50% of control. We conclude that the prolonged duration of actionof certain muscle relaxants because of cholestasis results fromboth inhibition of hepatic uptake by the accumulated bile saltsand a general deterioration of liver transport function.     

Glycogen and lactate synthetic pathways in human skeletal muscle in relation to obesity, weight reduction and physical training

The effects of obesity, weight reduction, and physical condition on the concentrations of glucose-6-phosphate (G-6-P) and glycogen, and the activities of glycogen synthase (GS) and lactate dehydrogenase (LD) were determined in resting vastus or gastrocnemius muscles of 40 healthy subjects. In obese women the activity of GS was 50% (P less than 0.05) lower than in lean women with similar levels of glycogen and G-6-P, whereas no difference was found in the activity of LD. Calorie restriction induced a 4.5% (P less than 0.05) decrease in body weight from 82.5 kg corresponding to a 3.2% (P less than 0.05) decrease in body mass index from 30.9 kg m-2. The total and fractional activities of glycogen synthase were increased by 50% (P less than 0.05), whereas muscle glycogen content was reduced by 40% (P less than 0.05). The G-6-P concentration and the activity of LD remained unchanged. In well-trained young men the concentrations of G-6-P and glycogen were, respectively, 250% (P less than 0.05) and 50% (P less than 0.05) higher than in non-trained. The fractional and total activities of GS were 90% (P less than 0.05) and 50% (P less than 0.05) higher, respectively, and the total activity of LD was only half (P less than 0.05) that of non-trained subjects. In conclusion, physical training enhances the activity of GS, despite a concomitantly increased glycogen content, and thus seems to exert a more efficient stimulus on glycogen synthase than weight reduction. It is indicated that physical training may provide a clinically important contribution to blood glucose reduction in hyperglycaemic conditions.     

Differential expression of the HECA-452 antigen (cutaneous lymphocyte associated antigen, CLA) in cutaneous and non-cutaneous T-cell lymphomas

The monoclonal antibody HECA-452 identifies an antigen that is primarily expressed on high endothelial venules, the preferred site of lymphocyte extravasation in lymphoid tissues, and also on a subpopulation of myelomonocytic cells and some T-cells. We investigated the expression of the HECA-452 antigen, also called the cutaneous lymphocyte associated antigen, in primary cutaneous and primary non-cutaneous T-cell non-Hodgkin's lymphomas. The tumour cells of cutaneous T-cell non-Hodgkin's lymphomas were positive in 53% of cases, while only 5% of the non-cutaneous lymphomas were positive. These differences were also present in morphologically identical tumours. Thus, the tumour cells in six out of 10 primary cutaneous anaplastic large cell T-cell lymphomas were positive, while they were positive in none of 24 primary non-cutaneous anaplastic large cell T-cell lymphomas. In general, primary cutaneous and primary nasal T-cell non-Hodgkin's lymphomas were devoid of HECA-452 positive high endothelial venules, whereas most nodal T-cell non-Hodgkin's lymphomas contained HECA-452 positive high endothelial venules. These observations suggest that the HECA-452 antigen might be related to a skin-associated type of lymphoid tissue and to lymphomas originating in the skin. However, the results of HECA-452 expression in secondary sites, and the clinical data of the primary cutaneous large cell lymphomas did not support the concept that HECA-452 is functionally involved in homing to the skin, or that loss of the HECA-452 antigen is related to tumour progression of primary cutaneous T-cell lymphomas.(ABSTRACT TRUNCATED AT 250 WORDS)     

Macrophage Populations in Different Stages of Induced Hepatic Metastases in Rats: an Immunohistochemical Analysis

Macrophages play a role in the host defence against cancer. Little is known about changes in macrophage populations during early metastatic growth. To evaluate the distribution, number and phenotype of macrophages in the development of hepatic metastases in a rat model (Wag/Rij rats and syngeneic CC531 colon carcinoma cell line), an immunohistochemical study was performed with the monoclonal antibodies ED1 (monocytes, and all macrophages), ED2 (resident tissue macrophages, like Kupffer cells) and ED3 (a subpopulation of macrophages which may play a role in the recruitment of lymphocytes). OX19 and Hisl4 were used to identify lymphocytes. In this study a new monoclonal antibody CC52 is described, which recognizes the CC531 tumour cell line. Liver metastases were induced by injection of CC53I colon carcinoma cells into a mesenteric vein. Rats were killed at various intervals. Results show three major macrophage populations during hepatic tumour growth: (1) on day 3, infiltrates are observed around the micrometastases, which contain mainly newly recruited macrophages (ED1⁺ and ED2⁻); (2) after 7 days, ED3-positive (ED3 ⁺) macrophages together with T lymphocytes are found in the infiltrates; (3) an increase in the number of ED2-positive (ED2⁺) Kupffer cells is observed in the liver parenchyma after 14 days. In conclusion, the present results suggest that various populations of macrophages, newly recruited (ED1⁺) as well as resident Kupffer cells (ED2⁺), are involved in the immune response against tumour cell deposits in the liver.     

Enteropathy-associated T-cell lymphomas have a cytotoxic T-cell phenotype

 

Aims:

Enteropathy-associated T-cell lymphoma (EATCL) is a rare complication of coeliac disease. We investigated whether EATCLs are the neoplastic counterparts of activated cytotoxic T-cells (CTLs).  

Methods and results:

Eight cases, clinically and histologically defined, were stained with monoclonal antibodies against components of the cytotoxic granules of CTLs, granzyme B and T-cell restricted intracellular antigen (TIA-1). It was found that all cases had a cytotoxic phenotype, i.e. expression of TIA-1 in most of the tumour cells, whereas granzyme B was found in six of eight cases, mostly in a smaller number of tumour cells compared to TIA-1. Since TIA-1 and granzyme B are expressed at different stages of activation of CTLs it is hypothesized that differences in expression between granzyme B and TIA-1 in EATCL represent different stages of activation in which the tumour cells are arrested. Clinically, seven of the eight patients died within 10 months after diagnosis of EATCL.  

Conclusions:

EATCL is a clinicopathological entity with a grim prognosis and with tumour cells representing a unique neoplastic equivalent of CTLs arrested in varying stages of activation.