长波紫外线照射对小鼠黑素瘤细胞的影响

[目的]研究不同剂量UVA照射对体外培养B_16小鼠黑素瘤细胞的形态、增殖率、黑素含量和酪氨酸酶活性的影响。[方法]选用B_16小鼠黑素瘤细胞 ,经不同剂量的UVA照射后 ,采用MTT法测定细胞的增殖 ,参照HideyaAndo等的方法测定酪氨酸酶活性和黑素含量。[结果]UVA照射后 ,黑素含量增加 (P<0.01) ,酪氨酸酶活性提高 (P<0.05) ,细胞增殖率上升 ,照射剂量在0.6、1.2、1.8J/cm2时 ,细胞增殖率的变化有显著性 (t=2.495、2.645、3.081,均为P<0.05)。[结论]随着照射剂量的增加 ,黑素含量增加 ,酪氨酸酶活性提高 ,细胞的增殖率增加 ,但UVA的促黑素瘤细胞增殖作用是有限的     

Secretion and function of the third component of complement (C3) by murine leukocytes.

Our new finding of de novo synthesis and secretion of C3 by both murine peritoneal macrophages and polymorphonuclear leukocytes (PMN) was confirmed by the incorporation of [35S]methionine into C3 molecules and their complete inhibition by cycloheximide. The methods of secretion of C3 from these two types of cells were compared by examining the C3 contents in their culture supernatants. Completely different modes of secretion were observed, i.e. although macrophages synthesize and secrete C3 constitutively, PMN has a mechanism to store the already synthesized C3 in the cell and secrete it in response to stimuli. Protein kinase C (PKC) activators, e.g. 12-O-tetradecanoyl-phorbol 13-acetate, dioctanoyl glycerol, and mezerein, as well as calcium ionophore A23187 stimulate the secretion of C3 from PMN. These results suggest the involvement of PKC and the calmodulin pathway. A very sensitive method for measuring C3 activity was developed which enabled us to show for the first time that C3 secreted by PMN had opsonizing activity and that particles cultured with PMN were phagocytosed effectively.     

Sulphanilic acid: divergent results in the guinea pig maximization test and the local lymph node assay

The guinea pig maximization test (GPMT) has proven to be a valuable tool for the identification of the skin sensitization potential of chemicals. The method identifies a hazard which can lead in the EC to compulsory labelling of that chemical. In the present study, data on sulphanilic acid derived from the GPMT has been compared with results from a second guinea pig assay (the cumulative contact enhancement test) and the murine local lymph node assay, both of which require only topical application of chemical. Except for the GPMT, no test identified any sensitizing activity associated with exposure to sulphanilic acid. These latter results are consistent with the experience gained from substantial human exposure in an occupational setting and from which no cases of allergic contact dermatitis to sulphanilic acid have arisen over a 20-year period. In consequence, it is questioned which test protocol in practice has given the more accurate identification of sensitization hazard relevant to man.     

Choline acetyltransferase activity in murine thymus.

Murine thymus has been demonstrated to contain both cholinergic receptors and acetylcholinesterase activity. In the present study we have investigated the presence of the enzyme choline acetyltransferase in this organ, which is responsible for the synthesis of acetylcholine. Results reported here demonstrate that (1) an appreciable amount of the enzyme is already present in the thymus on the day of birth; (2) its expression is developmentally regulated; and (3) thymic atrophy, induced in young (2-week-old) and adult (6-week-old) mice by i.p. injection of hydrocortisone for 2 days, is accompanied by significant reduction of choline acetyltransferase activity only in young mice. Altogether these results demonstrate the presence in the murine thymus of functionally relevant markers of the cholinergic system that might interface the interactions between the nervous and immune systems.     

Risk groups for clinical complications of norovirus infections: an outbreak investigation

Norovirus infections have been described as self-limiting diseases of short duration. An investigation of a norovirus outbreak in a university hospital provided evidence for severe clinical features in patients with several underlying diseases. Clinical outcomes of norovirus infection were defined. Risk-factor analysis targeting underlying diseases and medication was performed using multivariate analyses. In five outbreak wards, 84 patients and 60 nurses were infected (an overall attack rate of 32% in patients, and 76% in nurses). The causative agent was the new variant Grimsby virus. Severe clinical features, including acute renal failure, arrhythmia and signs of acute graft organ rejection in renal transplant patients, were observed in seven (8.3%) patients. In multivariate analyses, cardiovascular disease (OR 17.1, 95% CI 2.17-403) and renal transplant (OR 13.0, 95% CI 1.63-281) were risk-factors for a potassium decrease of >20%. Age >65 years (OR 11.6, 95% CI 1.89-224) was a risk-factor for diarrhoea lasting >2 days. Immunosuppression (OR 5.7, 95% CI 1.78-20.1) was a risk-factor for a creatinine increase of >10%. Norovirus infections in patients with underlying conditions such as cardiovascular disease, renal transplant and immunosuppressive therapy may lead to severe consequences typified by decreased potassium levels, increased levels of C-reactive protein and creatine phosphokinase. In the elderly, norovirus infection may lead to an increased duration of diarrhoea. Therefore patients at risk should be hospitalised early and monitored frequently. Strict preventional measures should be implemented as early as possible to minimise the risk of nosocomial outbreaks.     

Schedule-dependency of in vivo modulation of 5-fluorouracil by leucovorin and uridine in murine colon carcinoma

Summary The effect of leucovorin (LV) given in various doses and schedules on the in vivo antitumor activity and toxicity of 5-fluorouracil (5FU) was studied in two murine colon cancer lines, i.e., Colon 26 (relatively resistant to 5FU) and Colon 38 (5FU sensitive), maintained in Balb-c and C57B1/6 mice, respectively. Mice were treated weekly with 5FU at the maximum tolerated dose, alone and in combination with LV. In Colon 26, neither simultaneous administration of 5FU and LV nor 5FU combined with delayed administration of LV potentiated the antitumor activity of 5FU. LV given twice — 1 hr before (50 mg/kg) and then together (50 mg/kg) with 5FU (100 mg/kg) — gave significantly better delay of tumor growth of both tumor lines than 5FU did alone (100 mg/kg). No differences were found after a total LV dose of 100 or 200 mg/kg. Delayed administration of uridine (3500 mg/kg) allowed the use of higher 5FU doses, which improved the antitumor effect on Colon 26. Systemic toxicity led to moderate weight loss in treated mice, but was comparable for mice treated with 5FU alone or combined with LV. Hematological toxicity consisted of moderate leukopenia (nadir 40%), which was observed with the most active schedule and was less severe than with 5FU alone. This schedule did not cause thrombocytopenia, but after discontinuation the thrombocyte count showed an overshoot. Addition of uridine to this schedule reduced hematological toxicity only slightly. It is concluded that LV potentiated the antitumor activity of 5FU against two solid tumor lines, i.e., a relatively resistant and a sensitive murine colon carcinoma, and that toxicity was moderate.Abbreviations 5FU 5-fluorouracil - LV leucovorin (folinic acid, 5-formyl-tetrahydrofolate) - FdUMP 5-fluoro 2-deoxyuridine 5monophosphate - TS thymidylate synthase - CH2-THF 5-10 methylenetetrahydrofolate - UR uridine - GDF growth delay factor - TD tumor doubling time - MTD maximum tolerated dose - T/C mean tumor volume of treated mice divided by mean tumor volume of control mice     

Sequence Analysis of the Washington/1964 Strain of Human Parainfluenza Virus Type 1 (HPIV1) and Recovery and Characterization of Wild-Type Recombinant HPIV1 Produced by Reverse Genetics

A complete consensus sequence was determined for the genomic RNA of human parainfluenza virus type 1 (HPIV1) strain Washington/20993/1964 (HPIV1 WASH/64), a clinical isolate that previously was shown to be virulent in adults. The sequence exhibited a high degree of relatedness to both Sendai virus, a PIV1 virus recovered from mice, and human PIV3 (HPIV3) with regard to cis-acting regulatory regions and protein-coding sequences. This consensus sequence was used to generate a full-length antigenomic cDNA and to recover a recombinant wild-type HPIV1 (rHPIV1). Interestingly, the rHPIV1 could be rescued from full-length antigenomic rHPIV1 cDNA using HPIV3 support plasmids, HPIV1 support plasmids, or a mixture thereof. The replication of rHPIV1 in vitro and in the respiratory tract of hamsters was similar to that of its biologically derived parent virus. The similar biological properties of rHPIV1 and HPIV1 WASH/64 in vitro and in vivo, together with the previous demonstration of the virulence of this specific isolate in humans, authenticates the rHPIV1 sequence as that of a wild-type virus. This rHPIV1 can now be used to study the biological properties of HPIV1 and as a substrate to introduce attenuating mutations for the generation of live-attenuated HPIV1 vaccine candidates.An erratum to this article can be found at     

A quantitative ELISA for antigen-specific IgG subclasses using equivalence dilutions of anti-kappa and anti-subclass specific secondary reagents Application to the study of the murine immune response against the capsular polysaccharide of Neisseria meningitidis serogroup B

We have developed an enzyme-linked immunosorbent assay (ELISA) to measure murine antigen-specific IgG antibodies of defined subclass using precalibrated equivalence dilutions of anti-κ (in the standard) and each anti-IgG subclass-specific polyclonal secondary antibody (in the test sample). The calibration of secondary reagents could be carried out easily with a set of monoclonal antibodies (MoAbs) specific for all IgG subclasses. These MoAbs do not require purification or standardization. In addition the MoAbs can be of different antigenic specificity. Once the equivalence dilutions have been determined, they can be applied in a quantitative ELISA using the same antigen in the standard and sample, and using only one IgG subclass standard for the determination of all the IgG subclasses. The method is easy to standardize for many antigenic systems. It is particularly useful when the only standard available is one standardized MoAb of the appropriate specificity, and it could be adapted to use with standard polyclonal antibodies having a known content of total antigen-specific IgG bearing κ chains but unknown IgG subclass composition. The use of this method to quantitate IgG specific for the capsular polysaccharide of Neisseria meningitidis serogroup B (CpsB) gave highly reproducible measures with an interbatch CV of 5–6% similar for all IgG subclasses and low detection limits ranging from 0.3 ng/well for IgG3 to 0.8 ng/well for IgG2a. The IgG subclass response observed after immunization with live meningococci was mainly IgG2a (74%) and IgG2b (18%). Hyperimmunization modified this IgG distribution to one of mainly IgG3 (62%) and IgG1 (28%) which was maintained in the response to a single immunization 4 weeks later, possibly indicating the generation of resting B cells during continuous stimulation.     

Anti-idiotype and immunosuppressant treatment of murine lupus.

The effect of the administration of a xenogeneic anti-idiotype antibody (anti-Id33) to a cross-reactive idiotype (Id33) present on anti-dsDNA antibody was examined in 6-week-old (NZB/NZW) F1 (BWF1) female mice. The administration of anti-Id33 led to a transient reduction in immunoglobulins expressing Id33, followed by a rise at 30 and 34 weeks that was significantly higher than in untreated mice (P less than 0.05). Likewise, anti-dsDNA antibody levels were significantly higher at 10 and 18 weeks than in untreated mice (P less than 0.01). No differences were seen in survival to 40 weeks, proteinuria or the severity of glomerulonephritis. Concurrent administration of cyclosporin A (CyA) with anti-Id33 markedly ameliorated glomerular injury and proteinuria and improved survival. By contrast, glomerular injury, proteinuria and survival were worse in mice treated with cyclophosphamide plus anti-Id33, compared with untreated mice. Neither CyA nor cyclophosphamide treatment, when given with anti-Id33 altered serum levels of anti-dsDNA, anti-ssDNA or Id33+ immunoglobin, compared with untreated mice. The different effects of CyA and cyclophosphamide on T lymphocytes and their discrepant effects on glomerular injury when given with anti-Id33 in this model lead us to postulate a role for T lymphocytes in the glomerular injury of BWF1 lupus.