Tc-99m HMPAO SPECT imaging of the central nervous system in tuberous sclerosis

Tc-99m HMPAO was used to evaluate cerebral perfusion in a patient with tuberous sclerosis. The SPECT images demonstrated reduced HMPAO uptake in regions corresponding with MRI-confirmed locations of cortical tubers. These results indicate that the lesions are characterized by vascular perfusion deficits and support the hypothesis that cortical tubers result from developmental abnormalities of the embryonic central nervous system.     

Sites in the brain at which cholecystokinin octapeptide (CCK-8) acts to suppress feeding in rats: a mapping study

In this study, an examination was made of the sites in the brain of the rat at which the injection of cholecystokinin octapeptide (CCK-8) would alter food intake. Rats fasted for 24 hr received intracerebral injections of CCK-8 (1 nmol) or an equal volume of saline (0.5 microliters), into various sites in the brain through permanently implanted stainless steel cannulae. After prior acclimatisation to individual plexiglass compartments, latency to feed, as well as consumption of food and water during 0-20, 20-40 and 40-60 min after the injection, were recorded. The available food was the standard rat pellets, to which the animal otherwise had constant daily access. With this paradigm, active sites at which CCK-8 suppressed feeding were defined as sites at which consumption of food for 0-20 min was reduced by 25% or more, or the latency to feed was increased by 3 min or more after the injection of CCK-8, as compared to the effect of the injection of saline, made at the same site. Such active sites were most densely distributed in the rostral diencephalon, e.g. hypothalamus, the medial pontine area and lateral medulla, in the vicinity of the nucleus tractus solitarii (NTS). By grouping data for injections according to histologically identified sites, statistical analysis of groups of injections confirmed that these three major areas of the brain were active with regard to the suppression of feeding by CCK-8. These data suggest that CCK may not only initiate satiety messages, as a circulating hormone at peripheral sites, but also participate in the conduction of such information to the target in the brain by serving as a neurotransmitter in the lateral medulla (e.g. NTS), medial pontine area (e.g. relay station between the NTS and hypothalamus) and the lateral hypothalamus, where local release of CCK-8 after stomach loading has been observed.     

Successful surgical correction of persistent truncus arteriosus by an aortic homograft]

After palliative procedure a 2 years old girl with congenital heart disease was corrected with aortic homograft. Truncus arteriosus is a rare congenital heart disease and this is the first successfully corrected case in our country. Using homograft in this age group improves the early and late result of this type of corrective surgery.     

Postoperative echocardiographic study of patients following valvulotomy for critical valvular aortic stenosis

Authors report on long term follow up of 12 patients operated with critical valvular aortic stenosis. They could perform control echocardiography in 11 patients 4-83 (mean 29) months after valvulotomy. The size and function of the left ventricle was found to be satisfactory, with elevated ejection fraction. The cause of the significant pressure gradient between the left ventricle and the aorta is discussed emphasizing the importance of echocardiography in determining the optimal time for valve replacement or homograft implantation.     

Extensive cytocidal replication of lactate dehydrogenase-elevating virus in cultured peritoneal macrophages from 1-2-week-old mice

Indirect fluorescent antibody staining was used to examine the replication of lactate dehydrogenase-elevating virus (LDV) in primary cultures of peritoneal macrophages from BALB/c mice of different ages. Up to 80% of the total peritoneal macrophages from 1-2-week-old mice were susceptible to productive infection by LDV, though only 1-2% of the cells expressed detectable levels of IA antigen. The proportion of LDV-permissive peritoneal macrophages progressively decreased to 5-15% between 2 and 5 weeks of age of the mice. Macrophages from 9-day-old mice, when cultured in the presence of L cell conditioned medium, retained undiminished LDV permissiveness for at least 10 days in culture. The maximum proportion of LDV antigen-positive cells was detected between 8-10 h post infection of macrophages cultured from both 1-2-week-old and adult mice, concomitant with maximum LDV RNA synthesis. The LDV antigen positive macrophages disappeared between 12 and 48 h post infection. In cultures of macrophages from 9-10-day-old mice, the loss of infected cells was clearly due to cell killing, proving unequivocally that LDV replication is cytocidal. Disintegration of LDV-infected macrophages or phagocytosis of killed macrophages by surviving macrophages must be very sudden and complete since infected cells disappeared without the appearance of trypan blue-stainable cells in the culture. Ten cell lines established from macrophages of 2, 9, and 10-day-old mice all contained a small proportion of LDV-permissive cells (1-4%). Individual clones of one of the lines contained a similar small proportion of LDV-permissive cells.     

Polyclonal B cell activation of IgG2a and IgG2b production by infection of mice with lactate dehydrogenase-elevating virus is partly dependent on CD4+ lymphocytes

Concentrations of IgM and IgG isotypes were determined by capture ELISA in plasma of Swiss, BALB/c and C58/M mice. Plasma IgG isotype concentrations, especially of IgM, IgG1 and IgG2a, varied considerably between mouse strains, batches of mice of the same strain and individual mice and as a function of age. Infection of the mice with LDV, which is known to replicate primarily in a subpopulation of macrophages, consistently resulted in a rapid elevation of plasma IgG2a (or of IgG2b in some Swiss nu/+ mice), but no plasma IgG increases were observed in mice immunized with inactivated LDV. Plasma IgG2a elevation after LDV infection was greatly delayed and reduced by depletion of the mice of CD4+, but not of CD8+, T cells by administration of protein-G-purified anti-CD4 or anti-CD8 mAbs, and completely inhibited by repeated treatment of the mice with cyclophosphamide. Treatment with anti-CD4 mAbs, or cyclophosphamide also greatly reduced the production of anti-LDV antibodies, while not significantly affecting the replication of LDV in these mice. Nude Swiss mice also failed to produce anti-LDV antibodies, though supporting normal LDV replication. Plasma IgM, IgG1, IgG2a and IgG2b levels increased in LDV-infected nu/nu mice, but similar changes were observed in uninfected mice. The results indicate that the LDV-induced polyclonal activation of B cells requires productive LDV infection of mice and is, at least partly, dependent on functioning CD4+ cells. They suggest that productive infection of the LDV-permissive subpopulation of macrophages leads to the activation of CD4+ T lymphocytes of subset 1 and their Spleen cells from 5-day LDV-infected BALB/c mice incorporated [3H]thymidine 2-3 times more rapidly in vitro than spleen cells from companion uninfected mice, whereas their responses to concanavalin A and lipopolysaccharide were reduced 60-70%.     

Intracellular staining for TNF and IFN-gamma detects different frequencies of antigen-specific CD8(+) T cells

CD8(+) T lymphocytes are important mediators of adaptive immunity against certain viral, protozoan and bacterial pathogens. Activated CD8(+) T cells are able to induce cytolysis of infected cells (perforin and CD95-CD95L mediated pathways) and also elaborate cytokines, including IFN-gamma and TNF after appropriate MHC class I-peptide recognition. New technologies for the detection of antigen-specific CD8(+) T cells, including tetrameric MHC class I-peptide complexes, intracellular IFN-gamma staining and IFN-gamma ELISPOT analysis have revised our understanding of the magnitude of the CD8(+) T cell response to infection. Here, using intracellular cytokine staining, we compare detection of IFN-gamma and TNF in the analysis of pathogen-specific CD8(+) T cell lines and CD8(+) T cells after primary viral infection (LCMV) or secondary bacterial infection (Listeria monocytogenes). Under multiple conditions and with multiple epitopes, we find that staining for intracellular IFN-gamma consistently detects a higher frequency of antigen-specific CD8(+) T cells than detection of intracellular TNF. However, (a) intracellular staining for TNF can be used to detect antigen-specific CD8(+) T cell responses and (b) intracellular staining for cytokines is a useful approach for in vitro characterization of antigen-specific CD8(+) T cell lines.     

Primary total hip replacement--a survey of current practice and identifying changing trends

Primary total hip replacement (THR) surgery is the most commonly performed and successful reconstructive procedure in orthopaedic surgery. We performed a survey of Irish Orthopaedic consultants to elucidate current practices of primary THR in elderly and young patients and identify changing trends. There was an 83% response rate. Most respondents use a cemented THR in elderly patients. 69% use a different THR in younger patients compared to older patients. 9% refer younger patients to hip replacement specialist consultant colleagues. 70% report changing to a new implant or new technique in younger patients and 45% use a hybrid THR, 15% an uncemented THR, 15% perform hip resurfacing and 47% use different bearing surfaces. Only 17% use the Charnley hip prosthesis in younger patients. Young and active patients will place high demands on a new THR and newer techniques, implants and bearing surfaces are being adopted in the hope of better outcomes.     

CD8+-T-Cell Response to Secreted and Nonsecreted Antigens Delivered by Recombinant Listeria monocytogenes during Secondary Infection

Understanding how existing antivector immunity impacts live vaccine delivery systems is critical when the same vector system may be used to deliver different antigens. We addressed the impact of antivector immunity, elicited by immunization with attenuated actA-deficient Listeria monocytogenes, on the CD8(+)-T-cell response to a well-characterized lymphocytic choriomeningitis virus epitope, NP118-126, delivered by infection with recombinant L. monocytogenes. Challenges of immune mice with actA-deficient and with wild-type recombinant L. monocytogenes generated similar numbers of CD8(+) T cells specific for the NP118-126 epitope. High-dose immunization with actA-deficient L. monocytogenes resulted in substantial numbers of CD8(+) T cells specific for the L. monocytogenes LLO91-99 epitope in the effector and memory stages of the T-cell response. Challenge of these immune mice with recombinant L. monocytogenes resulted in rapid control of the infection and decreased CD8(+)-T-cell responses against both the secreted and nonsecreted form of the recombinant antigen compared to the response of na?ve mice. In contrast, mice immunized with a low dose of actA-deficient L. monocytogenes had approximately 10-fold fewer effector and memory T cells specific for LLO91-99 and a substantially higher CD8(+)-T-cell response against the recombinant antigen after challenge with recombinant L. monocytogenes. Although mice immunized with low-dose actA-deficient L. monocytogenes had a substantial recall response to LLO91-99, which reached the same levels by 5 to 7 days postchallenge as that in high-dose-immunized mice, they exhibited decreased ability to control L. monocytogenes replication. Thus, the level of antivector immunity impacts the control of infection and efficiency of priming responses against new antigens introduced with the same vector.