Epstein-Barr virus DNA in Reed-Sternberg cells of Hodgkin''s disease is frequently associated with CR2 (EBV receptor) expression

We studied 44 cases of Hodgkin's disease for the presence of Epstein-Barr virus (EBV) DNA, its localization and the expression of the EBV receptor on the tumour cells. EBV DNA was found in 52% (16/31) of the Hodgkin's lymphomas using the polymerase chain reaction. With a very sensitive non-radioactive DNA in situ hybridization technique in combination with immunohistochemistry for CD 30 or CD 15 antigens, EBV DNA was localized to Reed-Sternberg cells and its mononuclear variants. The relationship between the presence of EBV DNA and the expression of the EBV-receptor CR2 (CD 21) on Reed-Sternberg cells was studied using the same techniques and two different monoclonal anti-CD 21 antibodies. CR2 could be detected on a substantial number of the Reed-Sternberg cells in EBV DNA positive Hodgkin's lymphomas (9/12; 75%), whereas in EBV negative cases positivity with anti-CD 21 was rare (1/13; 8%). The results indicate that CR2 expression on Reed-Sternberg cells and the presence of EBV DNA sequences are frequently associated in Hodgkin's lymphomas.     

Seasonal covariation of the circadian phases of rectal temperature and slow wave sleep onset

There is a scarcity of well-controlled studies of the seasonal variation in circadian rhythmicity. In the present study, the circadian phase of rectal temperature and the onset of slow wave sleep were studied in a series of twelve 24-h experiments, one each month of the year, for six healthy subjects under controlled conditions in a climatic chamber. In winter, as compared with summer, the average circadian rhythm of rectal temperature was phase delayed by 45 min, and the average onset of slow wave sleep was phase delayed by 40 min. The temporal relationship between the circadian phase of rectal temperature and the timing of slow wave sleep was maintained throughout the year. Habitual rising and retiring times covaried as well. Furthermore, the circadian rhythm of rectal temperature followed the timing of the photoperiod across the year, but had a much smaller range of seasonal variation. Apparently, the seasonal variation in the photoperiodic zeitgeber is largely compensated for by the stabilizing influence of secondary zeitgebers. However, in healthy subjects some effect of photoperiodic variation can still be observed.     

Distribution of extracellular matrix components and their receptors in human lymphoid tissue and B-cell non-Hodgkin lymphomas

In this study the distribution patterns of various extracellular matrix components and their receptors (i.e. β1 integrins) in B-cell non-Hodgkin lymphomas were examined and compared to those in reactive lymphoid tissue. Neoplastic follicles within follicular lymphomas showed similar patterns to that observed in reactive follicles, which appeared to be strongly associated with the presence of follicular dendritic cells. Diffuse lymphomas of low and intermediate malignancy grade revealed features comparable to those of interfollicular areas of reactive lymphoid tissue, irrespective to which compartment the tumour cells were related. Highly malignant lymphomas, however, displayed unique extracellular matrix configurations, resulting from active matrix degradation by macrophages; this may support rapid tumour growth. Extranodal lymphomas showed virtually the same matrix patterns as their nodal counterparts, suggesting that (malignant) lymphoid cells generate (at least partly) their own specific microenvironment. In reactive lymphoid tissue β1 integrins were mainly found on resident cells and except for α4, α5 (and β1) the lymphoid cells expressed very little, if any, β1 integrins. In comparison, expression of these integrins on lymphoma cells was reduced (follicular lymphomas) or could not be detected at all (diffusely growing lymphomas); this might contribute to the growth pattern and metastatic properties of the tumours.     

Are infantile myofibromatosis,congenital fibrosarcoma and congenital haemangiopericytoma histogenetically related?

Infantile myofibromatosis, congenital fibrosarcoma and congenital/infantile haemangiopericytoma are generally considered distinct entities. Overlapping microscopic features between infantile myofibromatosis and congenital fibrosarcoma, and between infantile myofibromatosis and congenital/infantile haemangiopericytoma, however, have been noted, but not formally reported. This report concerns six neonatal tumours, each exhibiting more than one of the above patterns, supporting a histogenetic relationship among these entities. Immunohistochemistry for smooth muscle actin was found to be useful in the diagnosis of congenital/infantile haemangiopericytoma, and also served to support a histogenetic relationship with the other two entities under consideration.     

Electromyographic parameters related to clenching level and jaw-jerk reflex in patients with a simple type of myogenous cranio-mandibular disorder

A discriminant analysis has been applied on several electromyographic (EMG) parameters of the masseter and the anterior temporal muscles, related to clenching and the jaw-jerk reflex, to characterize jaw muscle function of patients with craniomandibular disorder (CMD) with respect to controls. The subject samples, matched for age, consisted of 20 females with myogenous CMD, and 20 symptom-free females. The jaw-jerk reflex was elicited by a downward-directed mandibular load, transmitted by a bite-fork causing a similar occlusion and bite-rise as a splint. The patients differed mainly from the controls by smaller maximum EMG activity in both muscle groups (P less than 0.05 with the bite-fork inserted). This finding was related to a smaller muscle strength as the EMG level did not improve with pain-free jaw muscles after therapy using a relaxation splint. Discriminating factors of secondary importance were an enhanced bilateral asymmetry in the muscle activity of the patients, and in the reflex amplitude normalized for background EMG activity. In all subject samples, the activity of the anterior temporal muscles decreased with respect to the masseter muscles when the bite-fork was inserted (P less than 0.05-0.001). The therapeutic effect of a relaxation splint may, in part, be related to a relief of the temporal muscles.     

Kinetics and Specificities of the T Helper–Cell Response to GP120 in the Asymptomatic Stage of HIV–1 Infection

Peripheral blood mononuclear cells from 36 asymptomatic HIV-1 seropositive individuals were tested longitudinally for in vitro T–cell proliferation and IL–2 production in response to synthetic peptides spanning the entire gp120 of HIV–1. At baseline, significant T–cell proliferation to pooled and individual peptides was observed in 15 of the 36 donors. After 12 months, proliferate responses to peptide pools were lost or decreased significantly in most donors. Responses appeared to fluctuate over time: at 12 months new recognition sites were detected in four of 10 donors showing T–cell proliferation at baseline, as well as in five of 15 donors with no previous proliferative responses. IL–2 production appeared to be a more sensitive and longer preserved parameter of T–helper cell function: at baseline the majority of donors with no T–cell proliferation produced IL–2 in response to pooled peptides. This response was not decreased significantly after 12 months. The overall patterns of response to both pooled and individual peptides were heterogeneous among donors. Multiple recognition sites were detected in both variable and conserved regions of gp120, but no pool or individual peptide was recognized by all responders. Functional T–cell responses were not statistically correlated to CD4° cell percentile and absolute numbers.