Increased apoptosis of immunoreactive host cells and augmented donor leukocyte chimerism, not sustained inhibition of B7 molecule expression are associated with prolonged cardiac allograft survival in mice preconditioned with immature donor dendritic cells plus anti-CD40L mAb.

BACKGROUND: We previously reported the association among donor leukocyte chimerism, apoptosis of presumedly IL-2-deficient graft-infiltrating host cells, and the spontaneous donor-specific tolerance induced by liver but not heart allografts in mice. Survival of the rejection-prone heart allografts in the same strain combination is modestly prolonged by the pretransplant infusion of immature, costimulatory molecule-(CM) deficient donor dendritic cells (DC), an effect that is markedly potentiated by concomitant CM blockade with anti-CD40L (CD154) monoclonal antibody (mAb). We investigated whether the long survival of the heart allografts in the pretreated mice was associated with donor leukocyte chimerism and apoptosis of graft-infiltrating cells, if these end points were similar to those in the spontaneously tolerant liver transplant model, and whether the pretreatment effect was dependent on sustained inhibition of CM expression of the infused immature donor DC. In addition, apoptosis was assessed in the host spleen and lymph nodes, a critical determination not reported in previous studies of either spontaneous or "treatment-aided" organ tolerance models. METHODS: Seven days before transplantation of hearts from B10 (H-2b) donors, 2x10(6) donor-derived immature DC were infused i.v. into C3H (H-2k) recipient mice with or without a concomitant i.p. injection of anti-CD40L mAb. Donor cells were detected posttransplantation by immunohistochemical staining for major histocompatibility complex class II (I-Ab) in the cells of recipient lymphoid tissue. CM expression was determined by two-color labeling. Host responses to donor alloantigen were quantified by mixed leukocyte reaction, and cytotoxic T lymphocyte (CTL) assays. Apoptotic death in graft-infiltrating cells and in areas of T-dependent lymphoid tissue was visualized by terminal deoxynucleotidyltransferase-catalyzed dUTP-digoxigenin nick-end labeling and quantitative spectrofluorometry. Interleukin-2 production and localization were estimated by immunohistochemistry. RESULTS: Compared with control heart transplantation or heart transplantation after only DC administration, concomitant pretreatment with immature donor DC and anti-CD40L mAb caused sustained elevation of donor (I-Ab+) cells (microchimerism) in the spleen including T cell areas. More than 80% of the I-Ab+ cells in combined treatment animals also were CD86+, reflecting failure of the mAb to inhibit CD40/ CD80/CD86 up-regulation on immature DC in vitro after their interaction with host T cells. Donor-specific CTL activity in graft-infiltrating cells and spleen cell populations of these animals was present on day 8, but decreased strikingly to normal control levels by day 14. The decrease was associated with enhanced apoptosis of graft-infiltrating cells and of cells in the spleen where interleukin-2 production was inhibited. The highest levels of splenic microchimerism were found in mice with long surviving grafts (>100 days). In contrast, CTL activity was persistently elevated in control heart graft recipients with comparatively low levels of apoptotic activity and high levels of interleukin-2. CONCLUSION: The donor-specific acceptance of rejection-prone heart allografts by recipients pretreated with immature donor DC and anti-CD40L mAb is not dependent on sustained inhibition of donor DC CM (CD86) expression. Instead, the pretreatment facilitates a tolerogenic cascade similar to that in spontaneously tolerant liver recipients that involves: (1) chimerism-driven immune activation, succeeded by deletion of host immune responder cells by apoptosis in the spleen and allograft that is linked to interleukin-2 deficiency in both locations and (2) persistence of comparatively large numbers of donor-derived leukocytes. These tolerogenic mechanisms are thought to be generic, explaining the tolerance induced by allografts spontaneously, or with the aid of various kinds of immunosuppression.     

Hip fracture in Hong Kong over the last decade--a comparison with the UK.

BACKGROUND: Hip fracture is a major public health problem in Asia and the UK. The objectives of this study were to describe the trends of hip fracture in Hong Kong over the last decade, and to compare the incidence in Hong Kong with that from the Wessex Health Region of the UK in 1995. METHODS: The number of hip fractures was calculated using hospital discharge records for all public hospitals in Hong Kong in 1991 and 1995. Age-specific incidence rates were then calculated using the mid-year census population for the two years. These rates were presented with previously reported age-specific rates for Hong Kong in 1966 and 1985. These age-specific rates for Hong Kong in 1995 were compared with rates for the Wessex Health Region of the UK. The total number of hip fracture expected in 2010 was calculated by applying the age-specific rates of 1995 to the projected population for 2010. RESULTS: In 1995, a total of 1138 men and 2782 women in Hong Kong fractured their hip. The age-specific rates had remained static from 1985 to 1995, after substantial rise from 1966 to 1985. In 1995, the rates of hip fracture rates were 11/1000 in women and 5/1000 in men who were 70 years and older. These rates were almost identical to those observed in the Wessex Health Region of the UK. CONCLUSION: The age-specific incidence rates of hip fracture had not risen in Hong Kong in the last decade. The incidence of hip fracture in Hong Kong was similar to that in the UK in 1995. The total number of patients with hip fracture in Hong Kong will increase substantially in the future, as a result of the ageing of the population.     

Experience with polychemotherapy based on cell synchronization, via intra-arterial infusions. Preoperative treatment of maxillofacial tumors]

Chemotherapy based upon cellular synchronisation via intra-arterial infusion was used in the treatment of 21 carcinomas of the maxillo-facial region. These tumours had never been treated either by surgery, nor by irradiation. This pre-operative treatment was not aimed at altering ghe indication for the type of operation decided upon at the outset. It was found that a combination of Vincristine, Bleomycine, Methotrexate and Dibromdulcide was more satisfactory than other types of chemotherapy. The most important complication of the method was a thrombosis of the common carotid.     

GABA-containing neuronal processes in normal and cortically deafferented dorsal lateral geniculate nucleus of the cat: an immunogold and quantitative EM study

Summary The qualitative and quantitative synaptology of flat synaptic vesicle containing F type terminals was analysed in normal and in chronically cortically deafferented dorsal Lateral Geniculate Nucleus (dLGN) of the cat using an electron microscopic immunogold technique for visualization of GABA. A direct correlation was found between the density (number of gold particles) of GABA immunostaining and the number of synaptic vesicles in different F terminals. This suggested a quantitative relationship between transmitter content and the number of vesicles in the labeled terminals. Not only the number but also the size of synaptic vesicles was found to be different in the two main groups of F profiles, i.e. the axonal F1 and dendritic F2 terminals. Measurement of the size of synaptic vesicles in F1 axon terminals revealed two subpopulations of these endings: F1₁ and F1₂ terminals with vesicle diameters of 31.56 ± 0.08 nm and 33.73 ± 0.12 nm (P < 0.01; Chi² test) respectively. The size of synaptic vesicles in axonal F1₂ terminals was identical to that found in F2 dendritic profiles, suggesting that both processes belonged to the same, intrageniculate (interneuronal) cell population. F1₁ terminals, however, appeared to be axonal endings of extrageniculate (most probably of perigeniculate) neurons. Quantitative analysis of the two types of GABAergic axon terminals revealed the geniculocortical relay cells to be the main postsynaptic targets for F1₁ (extrageniculate) terminals while F1₂ axons terminated equally on both interneurons and relay cells. Following chronic decortication of the dLGN, the distribution pattern of both GABAergic axonal types had changed considerably. As a result of a severe loss in relay cells, more F1₁ and F1₂ axon terminals were found on GABA-containing interneuronal processes than on relay cells. An increase in the number of F1 axonal terminals per neuron was also revealed, (particularly on GABAergic interneurons), suggesting a compensatory reactive synaptogenesis by both F axonal types following decortication.     

Percutaneous nitroglycerin absorption in rats.

Percutaneous nitroglycerin absorption was studied in shaved rats by monitoring unchanged plasma drug concentrations for up to 4 hr. Drug absorption from the neat liquid state or from an alcoholic solution was considerably poorer than that from a commercial ointment. This observation was unanticipated since the driving force for percutaneous drug absorption was assumed to be drug thermodynamics. Potential artifacts such as drug volatilization from the skin, reduction of surface area through droplet formation, and vehicle occlusion were investigated, but they did not appear to be responsible for the observed results. Two experimental aqueous nitroglycerin gels were prepared with polyethylene glycol 400. One gel contained just sufficient polyethylene glycol to solubilize the nitroglycerin; the other had excess polyethylene glycol to solubilize nitroglycerin far below saturation. Both gels gave extremely low plasma nitroglycerin levels. The composite data suggested that percutaneous nitroglycerin absorption is highly vehicle dependent and that this dependency cannot be explained by simple consideration of drug thermodynamic activity.     

Retransfusion acidosis after brief haemorrhagic hypotension in the dog.

Dogs under chloralose anasthesia were bled at a rate of 50 ml/min to a total of 25 ml/kg body weight and 2 minutes later a quick reinfusion of adequate volumes of blood, dextran, or Locke's solution was done. Within 2 minutes after reinfusion, the pH of arterial blood fell by 0.074--0.127; concurrently, PaCO2 rose by 9.2-12.9 mm Hg. A close correlation was demonstrated between these changes. After retransfusion, PaO2 and the arterial lactic acid level did not change significantly. Thus retransfusion acidosis in the dog appears after a brief hypotensive period, too, but cannot be attributed to a "washout" of lactate from the tissues.