The survival and growth of ovine afferent lymph dendritic cells in culture depends on tumour necrosis factor-alpha and is enhanced by granulocyte-macrophage colony-stimulating factor but inhibited by interferon-gamma

An in vitro culture system is described which allows an analysis of the signals responsible for the survival, growth and functional maturation of afferent lymph dendritic cells (ALDC), a subpopulation of migrating dermal dendritic cells involved in antigen carriage and presentation to T-cells. Purified ALDC survived and grew for up to 30 days in lymph node conditioned medium and survived 14 days in recombinant ovine (rov) TNF-alpha whereas none were detected after 24 h in rov GM-CSF, rov IFN-gamma or rh M-CSF. However, when rov GM-CSF was added to cultures along with rov TNF-alpha, increased numbers of ALDC compared with input numbers (growth) were recorded on Days 14 and 21. In contrast, when 50-200 units ml-1 of rov IFN-gamma were added to cultures of ALDC along with TNF-alpha or rov TNF-alpha plus rov GM-CSF, cell survival and growth was inhibited. Antibody blocking studies confirmed the cytokine specificity of these effects. ALDC cultured in rov TNF-alpha or rov TNF-alpha plus rov GM-CSF retained MHC Class-II and ov CD-1 antigen expression and accessory function for autologous ov CD-4 T-cell proliferation, although at reduced levels compared with freshly isolated cells. Neither fresh nor cultured ALDC expressed coagulation factor XIIIa.     

Self-disclosure and coping styles in men with cardiovascular reactivity

The purpose of this study was to investigate self-disclosure, emotion-focused, and problem-focused coping styles among men with borderline hypertension and two groups of normotensive men differentiated by parental hypertension. Because blood pressure reactivity may discriminate between hypertensive and normotensive men, subjects in these three groups were categorized as high or low cardiovascular reactors based on their blood pressure response to a mental arithmetic task. Self-disclosure and coping styles were investigated in relation to status effects within the doctor-patient relationship. Men with exaggerated blood pressure reactivity were less self-disclosive and used fewer emotion-focused coping strategies than men with no blood pressure reactivity. Normotensives with a history of parental hypertension were less self-disclosive than normotensives without a history of parental hypertension.     

Determination of the viremia threshold for dental cross-infection in a mouse model

An animal model of dental virus transmission was developed using the lactate dehydrogenase-elevating virus (LDV) of mice to study cross infection. Mouse-to-mouse cross-infection was carried out by scaling the teeth of LDV-infected donor mice with dental instruments, immediately prior to using the contaminated instruments on the teeth of recipient indicator mice. The level of donor viremia was found to correlate with the rate of virus cross-infection, with a viremia threshold level of 10(7.5) ID50/ml observed for dental cross-infection. The blood volume transferred during dental cross-infection was approximately 10(-4) to 10(-5) ml, demonstrating the inefficiency of virus cross-infection, since deposition of about 1000 virions on dental instruments was associated with the threshold limit. Virus transferred during dental cross-infection rapidly entered the blood circulation, showing that dental cross-infection was not dependent on an oral infection. The results from these model studies predict the general inefficiency of dental instrument virus cross-infection, and a further reduced likelihood of dental cross-infection with appropriately cleaned instruments.     

Dual immunodetection and hybridisation in situ of opsin mRNA and rhodopsin protein in retinal sections

We describe a simple method for combining in situ hybridisation and immunohistochemistry on the same retinal section. The technique was developed using a radiolabelled cDNA probe for opsin and an antibody (ROS1F4) against rhodopsin. This method retains the antigenic sites if immunocytochemistry is performed prior to in situ hybridisation. Opsin mRNA was found in the photoreceptor inner segment with rhodopsin immunolocalised to the photoreceptor outer segments. The technique should be applicable to numerous situations including analysis of the sequence of events in the expression and synthesis of the various opsins during retinal development and degeneration.     

In vivo cartilage formation from growth factor modulated articular chondrocytes

Recent procedures for autologous repair of cartilage defects may be difficult in elderly patients because of the loss of stem cells and chondrocytes that occurs with age and the slow in vitro proliferation of chondrocytes from aged cartilage. In this study secondary chondroprogenitor cells were obtained by modulating the phenotype of articular chondrocytes with growth factors and stimulating the proliferation of these cells in culture. Chondrocytes isolated from the articular cartilage of mature New Zealand White rabbits were exposed to a combination of transforming growth factor beta and basic fibroblast growth factor treatment. These cells ceased the production of Collagen II (a marker for the chondrocyte phenotype) and underwent a 136-fold increase in cell number. Next, the cells were placed in high density culture and reexpressed the chondrocyte phenotype in vitro and formed hyaline cartilage in an in vivo assay. Primary chondrocytes obtained from articular cartilage of elderly humans could be manipulated in a similar fashion in vitro. These human secondary chondroprogenitor cells formed only cartilage tissue when assayed in vivo and in tissue bioreactors. This approach may be essential for autologous repair of degenerated articular cartilage in elderly patients with osteoarthritis.     

Assessing declarative memory in schizophrenia using Wisconsin Card Sorting Test stimuli: the Paired Associate Recognition Test

The Paired Associate Recognition Test (PART) was developed to measure declarative memory using Wisconsin Card Sorting Test (WCST) stimuli, so that both tasks could be administered during functional neuroimaging to differentiate memory and executive function, and associated frontal and temporal lobe activation in schizophrenia. The current study was designed to compare PART and WCST performance in schizophrenic patients and to examine effects of medication and symptomatology. The PART, WCST, and standard declarative memory tasks were administered to 30 chronic schizophrenic patients and 30 matched healthy control subjects. Supporting task validity was the finding that patients were equally impaired on the PART and the WCST. Neuroleptics did not appear to affect performance. The effect of anticholinergic medication correlated negatively with WCST performance in a small subsample. Severity of schizophrenia-specific symptoms measured at intake on the Brief Psychiatric Rating Scale correlated negatively with performance on the WCST. These results support the application of the PART and WCST in future functional neuroimaging studies.