Neutrophil alkaline phosphatase activity increase in bacterial infections is not associated with a general increase in secretory vesicle membrane components.

The content of alkaline phosphatase (ALP) was determined in neutrophils isolated from patients with acute bacterial infections by a standard enzyme assay. Compared with control cells, patient cells exhibited about a fivefold increase in ALP activity. There was no difference between the ALP Km values of control and patient cells, which indicates that the elevated activity in patient cells was due to the presence of increased amounts of the enzyme. The ALP isozyme in both cell types was determined to be the tissue-unspecific ALP. The fact that much of the ALP activity was measurable only in the presence of detergent suggested that the enzyme was localized in the secretory vesicles, a putative reservoir of plasma membrane components. The amount and subcellular distribution of two other secretory vesicle membrane proteins, i.e., cytochrome b and complement receptor 3, were not altered; hence, we conclude that there was no general increase in amounts of secretory vesicle membrane constituents in the patient cells.     

Severe Neurological Complications after Central Neuraxial Blockades in Sweden 1990-1999

Background: Central neuraxial blockades find widespread applications. Severe complications are believed to be extremely rare, but the incidence is probably underestimated.

Methods: A retrospective study of severe neurologic complications after central neuraxial blockades in Sweden 1990-1999 was performed. Information was obtained from a postal survey and administrative files in the health care system. During the study period approximately 1,260,000 spinal blockades and 450,000 epidural blockades were administered, including 200,000 epidural blockades for pain relief in labor.

Results: The 127 complications found included spinal hematoma (33), cauda equina syndrome (32), meningitis (29), epidural abscess (13), and miscellaneous (20). Permanent neurologic damage was observed in 85 patients. Incidence of complications after spinal blockade was within 1:20-30,000 in all patient groups. Incidence after obstetric epidural blockade was 1:25,000; in the remaining patients it was 1:3600 (P < 0.0001). Spinal hematoma after obstetric epidural blockade carried the incidence 1:200,000, significantly lower than the incidence 1:3,600 females subject to knee arthroplasty (P < 0.0001).     

Chemoattractant-induced NADPH oxidase activity in human monocytes is terminated without any association of receptor-ligand complex to cytoskeleton

When the chemotactic peptide formylmethionyl-leucyl-phenylalanine binds to its cell surface receptor, a transmembrane signal is generated that activates the superoxide-producing NADPH oxidase of human phagocytes. Comparing monocytes and neutrophils with regard to the production of superoxide anion induced by the peptide, we found a similar time-course for both types of cells. In neutrophils, ligand binding induced a conversion of the receptor to a high-affinity form, a change suggested to be due to an association of the receptor-ligand complex to the Triton X-100-insoluble cytoskeleton. This event has been hypothesized to terminate the signal that activates the NADPH oxidase and thereby results in cessation of the cellular production of superoxide anion. Neutrophils preincubated with the cytoskeleton-disrupting drug cytochalasin B showed an increased and prolonged superoxide anion production after activation with the peptide, thus indicating that the cytoskeleton is involved in terminating this response. Formylmethionyl-leucyl-phenylalanine was also found to induce polymerization of actin in monocytes; however, cytochalasin B had no effect on the peptide-induced generation of superoxide anion in these cells. Furthermore, also in monocytes, ligand binding induced a conversion of the receptor to a high-affinity form; however, the receptor-ligand complex did not coisolate with the Triton X-100-insoluble cytoskeleton. These results indicate that, in monocytes, the NADPH oxidase activating pathway is terminated without any association of the receptor-ligand complex to the Triton X-100-insoluble cytoskeleton.     

Effects of two antiandrogen treatments on hirsutism and insulin sensitivity in women with polycystic ovary syndrome

Thirty-two women with polycystic ovary syndrome (PCOS) wereallocated to two antiandrogen treatment regimens; 28 women completedthe trial. Twenty women were treated with ethinyloestradioland cyproterone acetate (EO-CA) cyclically for 6 months andeight women were treated with the gonadotrophin releasing hormone(GnRH) analogue, goserelin for 6 months. Effects on hirsutism,insulin sensitivity (estimated by glucose clamp technique),blood lipids and hormones were measured. Women treated withEO-CA showed a reduction in hirsutism (P <0.05), and decreasedserum androgen concentrations (P <0.001) as well as reducedinsulin sensitivity (P <0.05). In women treated with goserelin,serum androgen concentrations also decreased (P <0.001),but there was no significant reduction of hirsutism. This group,however, showed an improved insulin sensitivity (P <0.05)despite an unchanged body mass index. Bone mineral density wasunaltered in both treatment groups. The reduction in androgenconcentrations caused by EO-CA was not paralleled by increasedinsulin sensitivity, most probably due to the effect of ethinyloestradiolper se. In contrast, the reduction in androgen concentrationsby goserelin was accompanied by an improved insulin sensitivity.     

Aberrant T-cell function in vitro and impaired T-cell dependent antibody response in vivo in vitamin A-deficient rats.

We have previously reported that vitamin A deficiency resulted in a reduced IgA antibody response to cholera toxin (CT) after per-oral immunization. In the present investigation we have studied the in vivo and in vitro immune response in vitamin A-deficient rats to two parenterally applied antigens, beta-lactoglobulin (beta-LG) and picrylsulphonic acid (TNP)-Ficoll. The serum IgG and IgM antibody responses to the T-cell dependent antigen beta-LG were significantly lower in the vitamin A-deficient rats than in the pair-fed control rats. No such differences were seen with the IgG and IgM responses to the T-cell independent antigen TNP-Ficoll. However, the biliary IgA and the serum IgE antibodies against both antigens were decreased in the vitamin A-deficient rats. In vitro lymphocyte stimulation with concanavalin A (Con A) or beta-LG gave higher T-cell proliferation rates in the vitamin A-deficient than in the control rats. Interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) levels in supernatants from Con A-stimulated mesenteric lymph node cells were also higher in the vitamin A-deficient rats, while IL-6 levels were decreased, which is consistent with an up-regulated Th1 activity. Proliferation studies on purified accessory cells and T cells from the deficient and the control rats, mixed in different combinations, showed that the T cells, but not the accessory cells, were disturbed in the vitamin A-deficient rats. Despite the increased T-cell activity in vitro the vitamin A-deficient rats had a lower delayed-type hypersensitivity (DTH) reaction than the pair-fed control rats. In conclusion, the increased IL-2 and IFN-gamma levels may reflect an up-regulation of Th1 cell function, while the decreased IgA, IgE and IL-6 levels indicate a suppression of Th2 cells. The disturbed T-lymphocyte function is manifested in vivo as a decreased DTH reaction and suppressed antibody production, the latter possibly due to a lack of B-cell switching and proliferation factors in vitamin A-deficient rats.     

Impaired mucosal antibody response to cholera toxin in vitamin A-deficient rats immunized with oral cholera vaccine.

To investigate the importance of vitamin A in the ability to respond to oral antigen administration, rats were fed a vitamin A-free diet. The animals were immunized perorally three times with a mixture of cholera toxin (CT) and a commercial cholera vaccine. The total immunoglobulin A (IgA) concentration as well as the specific IgA anti-CT antibody levels in serum and bile was significantly lower in the vitamin A-deficient animals than in the paired fed controls (animals that were fed a normal commercial diet in an amount equal to the amount the deficient animals consumed), while the levels of total and specific anti-CT IgG were not affected to the same extent by the vitamin A deficiency. The number of IgA anti-CT antibody-producing cells in the mesenteric lymph nodes after immunization was also significantly lower in the vitamin A-deficient rats than in the control rats. Supplementation of the diet with retinyl palmitate restored the ability to mount an IgA antibody response to the antigen, since the level of specific IgA anti-CT antibodies in relation to the total IgA concentration was as high in the vitamin A-supplemented group as in the paired fed control group. Restricted diet intake by itself did not affect the ability to respond adequately to the antigen since there was no difference in IgA anti-CT antibody level between paired fed rats and those being fed ad libitum. Assessment of transforming growth factor beta in cell cultures revealed no difference between vitamin A-deficient and paired fed animals. In summary, vitamin A deficiency resulted in a decreased number of IgA-producing cells, decreased IgA production, and a reduced ability to respond with IgA antibodies to the oral cholera vaccine.     

Local versus regional cerebral blood flow in the rat at high (hypoxia) and low (phenobarbital anesthesia) flow rates.

Local cerebral blood flow (CBF) was measured in rats, using an autoradiographic technique with 14C-iodoantipyrine as diffusible tracer, in situations with low, normal and high flow rates (phenobarbital anesthesia, analgesia with 75% N2O, and hypoxia, respectively). A comparison of the results with previous data obtained in conscious rats (Sakurada et al. 1978) demonstrates that 75% N2O moderately reduces local CBF in some, but not all, cortical and subcortical areas, that phenobarbital anesthesia reduces local CBF to between 30 and 65% of (conscious) control, and that pronounced hypoxia (arterial P02 about 25 mmHg) increases local CBF 3- to 4-fold. A comparison of the values obtained for cortical structures with those previously measured with a technique based on the Fick principle shows that the autoradiographic technique gives similar values at low and normal flow rates but that it moderately underestimates CBF at high flow rates, probably due to diffusion limitation.     

Inhibition of polymorphonuclear leucocyte locomotion by surface-bound antigen-antibody complexes

Delayed-type hypersensitivity responses to sheep erythrocytes were studied in inbred C57BL/6 and outbred NMRI mice fed either protein-deficient diets containing 8% and 4% casein or a normal diet with 27% casein. Following sensitization with optimal doses of antigen, the magnitude of the response was similar in mice fed the 8% protein and the normal diet. Large numbers of sheep red blood cells which suppressed the delayed hypersensitivity response in normal mice, failed to inhibit this response in animals fed the 8% casein diet. However, the titres of serum haemagglutinins were similar in mice of either dietary group immunized with high doses of antigen. Sensitized spleen cells from deficient mice kept on the 8% casein diet, had lower suppressor capacity than those from normal mice upon transfer into syngeneic hosts. Delayed-type hypersensitivity was significantly depressed in mice fed the 4% protein diet whereas the titres of serum antibodies to sheep erythrocytes were not diminished.     

An established immune response against ovalbumin is suppressed by a transferable serum factor produced after ovalbumin feeding: a role of CD25+ regulatory cells

We have previously demonstrated that rats fed ovalbumin (OVA) develop a tolerogenic activity in serum, which upon transfer induces tolerance to OVA and suppression of the immune response to a bystander antigen. Here, we have extended these studies and analysed if the tolerogenic activity in serum could suppress an established immune response in the recipients. Rats were immunized with OVA, 4 and 1 week prior to the transfer of serum from either OVA-fed or control animals. Rats that received serum from OVA-fed donors had significantly lower delayed-type hypersensitivity (DTH) reaction against OVA 1 week after the serum transfer compared with the controls, and the levels of immunoglobulin (IgG) anti-OVA antibodies were significantly lower 2 and 4 weeks after serum transfer. Monomeric OVA in amounts corresponding to the OVA transferred with serum did not induce the reduction of DTH response or IgG anti-OVA antibody levels. In vitro, the proliferation of OVA-stimulated spleen cells, taken from recipients of tolerogenic serum, was significantly lower compared with spleen cells from the controls. The in vitro suppression seemed to be mediated by a population of CD25+ cells, because the removal of such cells from OVA-stimulated spleen cell suspensions resulted in increased proliferation in cultures from rats receiving tolerogenic serum. Our results showed that the tolerogenic serum factor can suppress an established immune response in recipient animals, possibly through induction of regulatory CD25+ cells. Whether this capacity might be used to influence chronic inflammatory conditions needs to be investigated.