Cyclin D1 in astrocytic tumours: an immunohistochemical study

Forty-eight astrocytic tumours were stained immunohistochemically with antibodies to the cell cycle-regulating protein, cyclin D1, and to the proliferation marker MIB1 (Ki-67) using formalin fixed paraffin embedded tissue and a microwave antigen retrieval system. Cases were classified by the WHO system (1993). The labelling indices (LI) for both antibodies were compared with each other and with the tumour type. The mean labelling indices for both antibodies increased with the degree of malignancy, and a significant difference was seen between the pilocytic astrocytoma and diffuse astrocytoma together vs anaplastic astrocytoma and glioblastoma together. However, within each tumour type there was considerable variation in the labelling indices and a clear cut off value could not be demonstrated. There was a strong positive correlation between labelling indices for cyclin D1 and MIB1 in diffuse astrocytoma, but this correlation broke down increasingly in anaplastic astrocytoma and glioblastoma. There was poor correlation between cyclin D1 and MIB1 in pilocytic astrocytoma, a feature which appeared to separate them from the diffuse astrocytoma. Average labelling indices for cyclin D1 were higher than those of MIB1, which suggests that cyclin D1 positive cells represent a pool of cells from which proliferation and hence MIB1 expression can take place. In conclusion, cyclin D1 is overexpressed in astrocytic tumours, more so with increasing grade of malignancy and in a way which approximately correlates with MIB1 expression.     

Carbonic anhydrase II expression in fibrous astrocytes of the sheep

Immunohistochemical expression of carbonic anhydrase isoenzyme II (CAII) was demonstrated in a population of fibrous astrocytes in a young lamb and an adult sheep. Such cells were identified by co-expression of CAII and glial fibrillary acidic protein, nuclear morphology and their contribution of glial fibrillary acidic protein reactive processes to the glial limitans. Similar cells were not identified in neonatal lambs. As in man and mouse, CAII was also expressed in choroid plexus epithelium occurring in neonate, young and adult sheep brain. In contrast, however, to man and mouse, CAII was not expressed in sheep oligodendrocytes.     

Release of soluble transferrin receptor from the surface of human leukemic HL60 cells

Information regarding transferrin (Tf) receptor degradation is largely incomplete. HL60 cells were shown to release to their growth medium a Tf-binding protein which could be immunoprecipitated by anti-Tf receptor monoclonal antibodies (MoAbs) B3/25 and OKT9. Soluble Tf receptor was detected in the medium within one hour of replating of cells, and its release was inhibited at 4 degrees C. The affinity of Tf for the soluble receptor released by cells (kd = 2.3 x 10(-10) mol/L) was slightly lower than its affinity for the detergent-solubilized cellular receptor (kd = 1.2 x 10(-10) mol/L). 125I-Tf internalized and released by cells subsequently bound to Tf receptor released by the same cells, and soluble Tf receptor in the conditioned medium (CM) inhibited 125I-Tf binding to intact cells. The soluble Tf receptor isolated from the CM was smaller (78,000 daltons) than the cell surface receptor (94,000 daltons) when analyzed by gel electrophoresis under reducing conditions. Isolated cell membranes readily released soluble receptor; however, this release could be blocked by protease inhibitors. The soluble Tf receptor may represent the extracytoplasmic domain of the cellular Tf receptor released from the surface of HL60 cells through proteolytic cleavage by a membrane-based protease.     

Endothelial cell infection and thrombosis in paralysis caused by equid herpesvirus-1: Equine stroke

Summary Eight mares were infected with equid herpesvirus-1 subtype 1 isolated from a case of equine paresis. In two mares killed at 4 d.p.i. immunofluorescence showed endothelial cell infection together with thrombosis in the rete arteriosus of the nasal mucosa and also in the spinal cord of one of these mares. Circulating platelet counts in the other six mares fell as early as 2 d.p.i. and remained depressed for seven days. Circulating immune complexes started to appear at 2 d.p.i., reached maximum levels at 10 d.p.i., but were undetectable at 28 d.p.i. Three of the six remaining mares developed varying degrees of inco-ordination at 8 and 9 d.p.i. In the two inco-ordinate mares that were killed at 9 and 10 d.p.i. the haemorrhages in the spinal cord and brain were associated with extensive endothelial cell fluorescence and thrombus formation. Clinical paresis coincided with an increase in circulating complement fixing and neutralising antibodies which in all six mares were higher against the subtype 2 isolate than subtype 1.In five yearlings infected with a subtype 2 isolate of EHV-1 platelet counts remained normal and neither immune complexes nor viraemia, nor inco-ordination were detected.With 8 Figures     

Nipple development and pup-induced prolactin release in male rats treated prenatally with the antiandrogen flutamide

While maternal female rats display increases in circulating prolactin (PRL) concentrations in response to pup exposure, parental male rats fail to show such an increase. One possible explanation for the lack of an acute PRL response in parental male rats is that males do not have nipples and therefore do not receive stimuli from the pups comparable to those experienced by parental female rats. To examine the contribution of nipple presence and possible stimulation, i.e. suckling, in this sexually differentiated endocrine response, male rats were exposed from days 12-15 of gestation to the antiandrogen flutamide. As adults, flutamide-exposed males had nipples. These males and a group of control males were castrated in adulthood and treated with a 21-day hormone regimen (estradiol and progesterone) that effectively stimulates parental behavior in adult rats. Following hormone treatment, mammary tissue from one set of flutamide-treated males was examined histologically to assess nipple and mammary gland development and responsiveness of these tissues to hormonal stimulation. Additional sets of flutamide-treated and control animals were tested for parental behavior. These latter animals were implanted with indwelling atrial cannulae on day 4 of parental behavior and subsequently bled on day 6 in the absence of young and on day 8 after presentation of young. PRL concentrations did not change in either the flutamide-treated or control parental males bled in the presence or absence of young.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pneumothorax and other lung diseases: effect of altered resolution and edge enhancement on diagnosis with digitized radiographs

Prior studies have shown that pneumothorax is one of the more difficult entities to diagnose with digitized radiography. This study was designed to test whether increasing resolution from 1.25 to 2.5 line pairs per millimeter (lp/mm) and image processing (edge enhancement from unsharp masking) would increase accuracy and confidence in the diagnosis of pneumothorax, as well as normal cases and other forms of lung disease. Conventional radiographs were digitized with use of a laser reader and then reformatted as film hard copy. Eleven observers read 35 cases reformatted in three different ways (1.25 lp/mm, 2.5 lp/mm, 1.25 lp/mm unsharp mask). The images with finer resolution (2.5 lp/mm) and unsharp mask images were superior to those with coarser resolution (1.25 lp/mm) for the diagnosis of pneumothorax. There was no difference in diagnostic accuracy for normal patients. For abnormalities other than pneumothorax, the unsharp mask images were significantly worse. Confidence in the diagnosis of pneumothorax and other abnormalities was highest with the finest resolution (2.5 lp/mm).