The myogenic response in isolated rat cerebrovascular arteries: vessel model

We develop an integrated model of isolated rat arterial resistance vessel (RV), which can simulate its major property of myogenic response. The vascular smooth muscle cell is an important component of the wall of this vessel, and serves as a vasomotor organ providing the active tension generation that underlies the myogenic response of the wall to stretch. In the previous study, we focused on the development of a smooth muscle cell model that can mimic the strain-sensing and force-generating features of the myogenic mechanism. In the current model, we embed this cell model in a larger vessel wall configuration, and couple the time course of cellular contractile activation to macroscopic changes in vessel diameter. The integrated model is used to mimic published pressure-vessel diameter data obtained from isolated RVs that are mounted in a hydraulic test apparatus. The model provides biophysically based insights into the myogenic mechanism as it responds to changes in transmural pressure, in the presence and absence of Ca2+ blockers applied to the bathing fluid.It mimics measured data very well and provides a model that is able to link events at subcellular level to macroscopic changes in vessel diameter. The model initiates a mechanistic approach to investigate myogenic response, which has not been taken previously by any other models.     

A European multicenter study of immunoblotting in serodiagnosis of lyme borreliosis

A European multicenter study of immunoblotting for the serodiagnosis of Lyme borreliosis showed considerable variation in results obtained from tests with a panel of 227 serum samples. Six laboratories used different immunoblot methods, and a wide range of bands was detected in all the assays. Multivariable logistic regression analysis of data from individual laboratories was used to determine the most discriminatory bands for reliable detection of antibodies to Borrelia burgdorferi sensu lato. These bands were used to construct individual interpretation rules for the immunoblots used in the six laboratories. Further analysis identified a subset of eight bands, which were important in all the laboratories, although with variations in significance. Possible European rules, all closely related, were formulated from these bands, although there was no single rule that gave high levels of sensitivity and specificity for all the laboratories. This is a reflection of the wide range of methodologies used, especially the use of different species and strains of B. burgdorferi sensu lato. The panel of European rules provides a framework for immunoblot interpretation which may be adapted in relation to the characteristics of Lyme borreliosis in local areas.     

Isodicentric X chromosome in a moderately tall patient with gonadal dysgenesis: lack of effect of functional centromere on inactivation pattern.

An isodicentric X chromosome (46, X idic (X)(pter leads to qter::qter leads to pter)) with a single functioning centromere was found in all lymphocytes and fibroblasts examined from a female patient 171.5 cm in height presenting with primary amenorrhoea. Replication of the abnormal chromosome was consistently late. In some cells the pattern was asymmetrical but the asymmetry did not appear to relate to the position of the active centromere.     

Primary primitive neuroectodermal tumor of the cauda equina

Primitive neuroectodermal tumors (PNETs) are aggressive neoplasms composed predominantly of undifferentiated cells that show evidence of neural differentiation. Although their classification has been controversial, PNETs are well recognized primary tumors of both central and peripheral nervous systems. PNETs must be distinguished from other round-cell tumors, including Ewing's sarcoma, lymphoma, rhabdomyosarcoma, and small cell carcinoma. Intraspinal PNETs are rare neoplasms that are usually metastatic in origin. We describe the eighth reported primary PNET of the cauda equina that developed in a 52-year-old man with no significant medical history. The tumor was characterized by Homer-Wright rosettes and immunoreactivity for CD99, glial fibrillary acidic protein, neuron-specific enolase S100, and synaptophysin. The anatomic location of primary intrathecal PNETs is important as those arising in the spinal cord develop in the central nervous system, whereas those arising in the cauda equina develop in the peripheral nervous system. The histogenesis of intrathecal PNETs may be multifactorial.     

Effect of aging on human aortic protein composition. II. Two-dimensional polyacrylamide gel electrophoretic analysis

Arterial intima proteins were extracted by 9 M urea from matching histologically atheroma-free areas of 27 human thoracic aortas of both sexes from younger (15-34) and older (35-82) age groups and studied after separation by high-resolution two-dimensional polyacrylamide gel electrophoresis. Seventeen specific protein groups on each gel were identified according to their relative charges and molecular weights and their distribution in the two age groups compared. Some plasma-derived proteins occurred rarely in young aortas while they were consistently found in those from older cases, i.e., protein group 4 (alpha 1-antichymotrypsin) 1/13 (8%) vs 12/14 (86%), group 7 (haptoglobin beta-chain) 1/13 (8%) vs 13/14 (93%) and groups 6 and 9 (IgG chains) 3/13 (23%) vs 9/14 (64%), respectively. Other plasma-derived proteins such as group 3 (albumin) and 5 (alpha 1-antitrypsin) were identified in all samples of both age groups but their expression in the aortic intima increased with age. Proteins which are typically found intracellularly such as those from groups 11 (actin), 12 (cytoskeleton proteins), and 13 (tropomyosin-like proteins) appeared in samples of intima of both age groups but were less apparent in older specimens. These studies suggest that the changes in aortic intima protein distribution in the absence of atherosclerosis closely correlate with histological changes such as intimal thickening often found with aging, providing new sensitive markers of vascular senescence.     

Adaptive sensitivity of the surround mechanism of cat retinal ganglion cells

Experimental Brain Research - The spatial distribution of the surround's adaptation mechanism was studied in X-and Y-cells in the cat's retina. Adaptive sensitivity was assessed with...     

Morphometric analysis of breast carcinoma: association with survival.

In a retrospective study of 126 cases of infiltrating ductal adenocarcinoma of the breast the percentage area of sections of each neoplasm occupied by malignant cells was assessed by morphometry. The duration of postoperative survival was related to the area occupied by tumour cells within a neoplasm; the greater the tumour cell area to stroma the more prolonged the survival. This variable seemed to be independent of histological grade and was of greater prognostic importance than the diameter of the neoplasm. Furthermore, combination of percentage of tumour area with histological grade provided greater information on the survival characteristics of these patients. Extensive tumour necrosis was a particularly poor prognostic feature.     

Some properties of dendritic macrophages from peripheral lymph

Peripheral lymph was collected from the skin and liver of sheep, and from the intestine of rats. The dendritic macrophages contained in it were isolated by centrifuging the lymph over a layer of 'Nycodenz'. Similar cells were produced by culturing mononuclear cells from venous blood, but the yields were very small. The numbers of dendritic cells in the lymph from the legs of sheep increased five-fold after xylene had been applied to the skin. Dendritic macrophages displayed abundant class II histocompatibility antigens on their surfaces, as well as immunoglobulins. Although the latter were probably acquired passively, they remained present for several days on cells cultured in vitro. When in vitro, dendritic cells could be shown to phagocytose marker particles, such as latex beads, but their performance was unimpressive compared to macrophages from the peritoneal cavities of rats. In contrast, their ability to phagocytose rapidly T4 phage or influenza viruses unequivocal and striking.