Peripheral blood lymphocytes from Eimeria tenella infected chickens produce gamma-interferon after stimulation in vitro

Protective immunity to infection by Eimeria parasites has been demonstrated to be dependent on T-cell mediated immune responses and may be associated with the release of cytokines. We have previously shown that the proportion of CD8-expressing T-cells in the peripheral blood of chickens increases transiently at 8 days after a primary infection with Eimeria tenella oocysts. The increase in the CD8⁺ population coincided with an increased proliferative lymphocyte response upon stimulation with E. tenella sporozoite antigen in vitro. In this study, we further investigated the functional activity of these peripheral blood leucocytes (PBL) by determining both the potential to proliferate and to produce IFN upon stimulation with E. tenella sporozoite antigens and mitogens. Enhanced proliferative responses to parasite antigen were accompanied by reduced responses to T-cell mitogens around 1 week of infection. The IFN activity in the supernatants of the stimulated PBL was measured by the ability to inhibit Semliki Forest Virus (SFV) replication in chicken embryo fibroblasts (CEF) and to activate macrophages, as measured by nitric oxide production. At eight days after infection the highest levels of virus inhibition and NO-production were detected upon stimulation with both E.tenella sporozoite antigen and mitogen. A strong correlation between the individual data of the two methods was found at this timepoint indicating that the produced cytokine was indeed IFN-γ. These results suggest that around eight days after a primary E. tenella infection a parasite specific T-cell subset with the capacity to produce IFN(-γ) is circulating which could be involved in the induction of protective immunity against Eimeria tenella .     

Immune responses to eimeria: quantification of antibody isotypes to Eimeria tenella in chicken serum and bile by means of the ELISA

The enzyme-linked immunosorbent assay (ELISA) has been used to study the serum IgM and IgG response and the bile IgA and IgM response of chickens to a primary, secondary and tertiary inoculation of Eimeria tenella. In the serum there was a rapid and transient IgM response to the primary infection; second and third inoculations of oocysts had comparatively little effect on the concentrations of this antibody isotype. This differed from the specific IgG response which was later and of similar magnitude after each inoculum. In the bile, specific IgA reached its highest concentrations 9-10 days after the primary inoculation and then declined rapidly. The second and third inoculations each induced low concentrations of this isotype. The specific biliary IgM response to the primary inoculation was similar in profile to that of the IgA, but IgM was detected only on day 14-15 after the second and not at all after the third inoculation. The findings are discussed and are compared with the results obtained using other host species, principally the rat, and with other gut organisms. The relevance of the antibody response in resistance to eimerian infections is also discussed.     

Neutrophil-mediated cytotoxicity to schistosomula of Schistosoma mansoni in vitro: studies on the kinetics of complement and/or antibody-dependent adherence and killing

The capacity of rat peritoneal neutrophils to adhere to and kill schistosomula of Schistosoma mansoni in vitro has been investigated. Neutrophils adhere readily to schistosomula in the presence of antibody plus complement (C) (fresh immune rat serum), antibody alone (heat-inactivated immune rat serum) and C alone (fresh normal rat serum), but not with heat-inactivated normal rat serum. However, schistosomular killing is only achieved with neutrophils and fIRS or MRS. In the presence of hiIRS the cells detach after 6 h without producing a significant level of parasite death. The system involving neutrophils plus fIRS is the most efficient in terms of serum dilution and the rate of schistosomular killing. The complement-dependent antibody involved in this system belongs to the class IgG and occurs in rat serum at peak titres, 6–8 wk after a primary schistosome infection. Neutrophil adherence in the presence of MRS depends upon the generation of C3b molecules at the parasite surface via the alternative pathway of C activation. Studies on the antibody alone system indicate that the lack of significant schistosomular killing might result from the absence of factors which stimulate cell migration, since if a chemokinetic agent is introduced into the assay a 30% increase in mortality is recorded. The possible participation of neutrophils in the destruction of a primary and/or challenge infection in vivo is discussed.     

氯法齐明抗结核分枝杆菌的体内外活性研究

目的 评价氯法齐明(clofazimine,CLF)在体外及体内抗结核分枝杆菌的活性,为临床应用提供依据.方法 应用微孔板指示剂法,测定氯法齐明对结核分枝杆菌标准株H37Rv及临床分离耐多药结核分枝杆菌(30株)的MIC;建立小鼠静脉感染H37Rv的结核病模型(105 CFU/只),根据氯法齐明的不同剂量,分为3个治疗组:20 mg/kg,每周给药5次(CLF-1组);10 mg/kg,每周给约5次(CLF-2组);20 mg/kg,每周给药2次(CLF-3组);治疗30 d后进行肺、脾组织活菌计数,应用单冈素方差分析,比较氯法齐明在小鼠体内的抗结核分枝杆菌活性.结果 氯法齐明对结核分枝杆菌H37Rv的MIC为0.12～0.24 μg/ml;对30株耐多药结核分枝杆菌临床分离株的MIC为0.12～1.92 μg/ml.在小鼠结核病治疗模型中,3个治疗组的小鼠肺活菌计数分别较空白对照组降低2.92、1.78和1.39 lg CFU,均具有统计学意义(F=74.09,P＜0.01).结论 氯法齐明具有较好的体外及体内抗结核分枝杆菌活性,值得进一步研究.     

Variability in quantitative measurement of the same segment with two different intravascular ultrasound systems: in vivo and in vitro studies.

We evaluated two different intravascular ultrasound (IVUS) systems, Atlantis and Intrafocus, to verify their accuracy and reproducibility. In an in vivo study on 20 consecutive patients with coronary artery diseases, the minimum lumen diameter (MLD), vessel diameter, lumen area (LA), vessel area, plaque area, and area stenosis rate (% AS) were respectively measured. In an in vitro study, MLD and LA were measured in four metal tubes with different diameters. All of the measured values except for % AS by Atlantis were significantly larger than the values obtained with Intrafocus. Nonuniform rotational distortion (NURD) was estimated as 34% in Atlantis and 1% in Intrafocus. The measurements by Atlantis were larger than the true values while the measurements by Intrafocus were less than the true values in all four metal tubes. These findings suggest that we should clearly avoid the use of different IVUS systems in the same study.     

人源抗狂犬病毒G蛋白单链抗体的生物学鉴定及其小鼠体内中和活性测定

目的对从噬菌体抗体库中筛选的人源抗狂犬病毒单链抗体A12进行生物学活性鉴定及小鼠体内中和活性检测。方法用免疫荧光法检测其结合感染狂犬病毒CVS的鼠脑组织的能力,用小鼠中和实验测定A12表达产物的体内中和活性。结果免疫荧光试验显示A12表达产物与感染CVS的鼠脑细胞有强的荧光反应。小鼠中和试验结果表明,A12ScFv样品组小鼠有9只存活,而对照组小鼠全部死亡。A12在729倍稀释时能100%保护小鼠抵抗致死量狂犬病毒的脑内攻击。结论A12对狂犬病毒具有一定的中和活性,有可能被用于暴露后狂犬病的预防。     

Danazol: in vitro effects on human hemopoiesis and in vivo activity in hypoplastic and myelodysplastic disorders

Abstract: We examined the effects of danazol on in vitro growth of human bone marrow and peripheral blood progenitor cells from 15 normal donors and 5 myelodysplastic patients, and on in vivo hemopoiesis in 30 patients with hypoplastic or myelodysplastic disorders. At concentrations similar to that reported as the plasma level after oral administration, danazol significantly increased CFU-GM colony growth in all normal donors, while the influence on CFU-E, BFU-E, CFU-MK and CFU-GEMM colony growth was less evident. The stimulatory effect on CFU-GM was observed even after accessory cell depletion. No stimulatory effect either in vitro on the growth of all hemopoietic progenitors or in vivo was observed in 15 myelodysplastic patients, while 7 complete and 3 partial hematological responses occurred in 15 patients with hypoplastic disorders. In conclusion, our results suggest that danazol exerts a direct stimulatory activity in vitro at least on CFU-GM, and a hemopoietic stimulatory effect in vivo in hypoplastic but not in myelodysplastic disorders.     

In vivo and in vitro binding of 1,2-dibromoethane and 1,2-dichloroethane to macromolecules in rat and mouse organs

Summary The comparative interaction of equimolar amounts of 1,2-dichloroethane and 1,2-dibromoethane with rat and mouse nucleic acids was studied in both in vivo (liver, lung, kidney and stomach) and in vitro (liver microsomal and/or cytosolic fractions) systems. In vivo, liver and kidney DNA showed the highest labeling, whereas the binding to lung DNA was barely detectable. Dibromoethane was more highly reactive than dichloroethane in both species. With dichloroethane, mouse DNA labeling was higher than rat DNA labeling whatever the organ considered: the opposite was seen for the bioactivation of dibromoethane. RNA and protein labelings were higher than DNA labeling, with no particular pattern in terms of organ or species involvement. In vitro, in addition to a low chemical reactivity towards nucleic acids shown by haloethanes per se, both compounds were bioactivated by either liver microsomes and cytosolic fractions to reactive forms capable of binding to DNA and polynucleotides. UV irradiation did not photoactivate dibromoethane and dichloroethane. The in vitro interaction with DNA mediated by enzymatic fractions was PB-inducible (one order of magnitude, using rat microsomes). In vitro bioactivation of haloethanes was mainly performed by microsomes in the case of dichloroethane and by cytosolic fractions in the case of dibromoethane. When microsomes plus cytosol were used, rat enzymes were more efficient than mouse enzymes in inducing a dibromoethane-DNA interaction: the opposite situation occurred for dichloroethane-DNA interaction, and this is in agreement with the in vivo pattern. In the presence of both metabolic pathways, addition or synergism occurred. Dibromoethane was always more reactive than dichloroethane. An indication of the presence of a microsomal GSH transferase was achieved for the activation of dibromoethane. No preferential binding in vitro to a specific polynucleotide was found. Polynucleotide labeling was higher than (or equal to) DNA binding. The labeling of microsomal RNA and proteins and of cytosolic proteins was many times lower than that of DNA or polynucleotides. The in vivo and in vitro data reported above give an unequivocal indication of the relative reactivity of the haloethanes examined with liver macromolecules from the two species and agree, on the whole, with the relative genotoxicity (DNA repair induction ability, mutagenicity and carcinogenicity) of the chemicals.Abbreviations CBI covalent binding index - EDTA ethylenediaminetetraacetate - GSH glutathione, reduced form - NADP nicotinamide adenine dinucleotide phosphate - NADPH nicotinamide adenine dinucleotide phosphate, reduced form - PB phenobarbitone - poly(A) polyadenylic acid - poly (C) polycytidylic acid - poly (G) polyguanylic acid - poly (U) polyuridylic acid - poly (G) polyguanylic acid - poly (U) polyuridylic acid - POPOP 1,4-bis[2-(5-phenyloxazolyl)]-benzene - PPO diphenyloxazole - Tris tris(hydroxymethyl)aminomethane - UV ultraviolet Supported by a grant from Ministero della Sanità, Rome, Piano di ricerca nel campo delle malattie sociali, no. 500.4/RSC/135/L/1208     

In vitro and in vivo stability of diluted recombinant factor VIII for continuous infusion use in haemophilia A

Summary.  Factor VIII (FVIII) replacement by continuous infusion (CI) is used postoperatively or after significant bleeding. For young paediatric patients, CI may require FVIII dilution. Variable stabilities of diluted full-length recombinant FVIII Kogenate^® FS (KG-FS) have been reported under different storage conditions. We investigated the recovery and stability of diluted KG-FS in vitro and in vivo . Kogenate^® FS was diluted to 50–120 U mL⁻¹ and its recovery and stability in glass vials or polypropylene syringes was determined. Furthermore, stability of KG-FS diluted to 80 U mL⁻¹'administered' via single- and double-pump mock CI systems was tested. Finally, the in vivo stability of KG-FS diluted to ∼60 U mL⁻¹ and administered postsurgically by CI with the double-pump to a paediatric patient with severe haemophilia A undergoing implantable venous access device placement was investigated. Initial KG-FS dilution resulted in a 10–20% FVIII loss; a further 25–30% loss occurred over 72 h in vials or syringes. With the double-pump, 1 h recovery was 35%, increasing to 80% by 24 h; the initial losses were because of the Y-infusion of a 10-fold larger volume of saline concomitantly with the FVIII. In vivo , CI resulted in stable FVIII activity levels within the target range. These in vitro results are important for the generation of CI guidelines for diluted KG-FS in the paediatric haemophilic population. That FVIII losses occur upon dilution and with the double-pump does not preclude use of diluted KG-FS. Indeed, stable FVIII levels were maintained when diluted KG-FS was administered by CI with the double-pump to a paediatric patient postsurgically.     

Downregulation of AP-1 gene expression is an initial event in the oridonin-mediated inhibition of colorectal cancer: studies in vitro and in vivo

Background and Aim: Oridonin is the active ingredient isolated from the Chinese herb Rabdosia rubescens. We used both in vivo and in vitro approaches to elucidate the underlying mechanism of the oridonin‐mediated inhibition of colorectal cancer. Methods: Two colorectal cell lines, Lovo and SW480, were treated with oridonin in solution. The effect of this treatment on the inhibition of the cell proliferation rate was determined by the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide method. The changes in gene expression that occurred in both cell lines in response to treatment with oridonin were determined via an illumine expression sensor. Additionally, a colorectal cancer colostomy implantation model was established. Animals were injected intraperitoneally with an oridonin solution. Results: The treatment of Lovo and SW480 cells with oridonin inhibited cell proliferation in a dose‐dependent manner. Furthermore, the rate of inhibition increased with prolonged treatment. The growth rate of the colorectal cancer colostomy implantation model was significantly lower than control cells when treated with oridonin (P < 0.001), which meant that oridonin treatment had a significant effect on the tumor growth rate. In the tumor model, activator protein‐1 (AP‐1) was the only gene found to be downregulated after oridonin treatment by the gene expression sensor. After 4 weeks of treatment, AP‐1, nuclear factor‐κB (NF‐κB) and P38 were all found to be downregulated. Conclusions: Our study confirmed the inhibitory effects of oridonin on colorectal cancer. These results indicate that the downregulation of AP‐1 might be an initial response to treatment by oridonin. This regulation could, in turn, affect the expression of the NF‐κB and mitogen‐activated protein kinase pathways, thereby inhibiting tumor growth.     

In vivo and in vitro hepatic 31P magnetic resonance spectroscopy and electron microscopy of the cirrhotic liver

Abstract: In vivo ³¹P magnetic resonance spectroscopy (MRS) provides direct biochemical information on hepatic metabolic processes. To assess in vivo changes in hepatic ³¹P MRS in liver transplant candidates, we studied 31 patients with cirrhosis of varying aetiology; 14 with compensated cirrhosis (Pugh's score <7) and 17 with decompensated cirrhosis (Pugh's score <8). Underlying cellular abnormalities were characterised using in vitro ³¹P MRS and electron microscopy. In vitro spectra were obtained from liver extracts, freeze-clamped at recipient hepatectomy, from all subjects. Electron microscopy of liver tissue was also performed in 17 cases. Relative to nucleotide triphosphates, elevations in phosphomonoesters and reductions in phosphodiesters were observed in vivo with worsening liver function. In vitro spectra showed elevated phosphoethanolamine and phosphocholine, and reduced glycerophosphorylethanolamine and glycerophosphorylcholine, mirroring the in vivo changes, but no distinction was noted between compensated and decompensated cirrhosis. With electron microscopy, functional decompensation was associated with reduced endoplasmic reticulum in parenchymal liver disease, but elevated levels in biliary cirrhosis. We conclude that in vivo spectral abnormalities in cirrhosis are consistent with alterations in phospholipid metabolism and quantity of endoplasmic reticulum. However, in individual patients the biopsy results do not always mirror in vivo findings.     

Seasonal variations of in vivo and in vitro melatonin production in a passeriform bird, the house sparrow (Passer domesticus)

Melatonin, released from the pineal gland, is an important signal within the circadian pacemaking system of passeriform birds. Until now, seasonal variations in melatonin production have only been examined in a few avian species and the role of melatonin in the regulation of annual rhythms in birds is unclear. We investigated plasma melatonin in a group of house sparrows kept in an outside aviary in spring (March/April), summer (May/June), autumn (September/October), and winter (December/January). The durations of elevated melatonin values mirrored the seasonal changes in night length to a certain degree, the melatonin signal being longest in winter and shortest in summer. Additionally, plasma melatonin peak amplitudes differed significantly among seasons, with highest values in spring and summer and lowest values in winter. Cultured explanted pineal glands obtained from animals in winter and summer showed patterns of in vitro melatonin release comparable to in vivo circulating melatonin with different durations of elevated melatonin and peak amplitude values. These data indicate that the circadian pacemaking system of the house sparrow changes properties seasonally, either as a result of endogenous mechanisms or in response to environmental conditions. These properties are maintained in the pineal gland even after isolation from the animal.     

The in vitro effects of vincristine on peripheral blood leukocyte progenitor cells (CFU-C) in patients in blast crisis of chronic granulocytic leukemia: Correlation with clinical response

The in vitro sensitivity of circulating progenitor cells (CFU-C) of 20 patients in blast crisis of chronic granulocytic leukemia (CGL) to vincristine was correlated with the clinical response to vincristine in vivo. Eleven patients who achieved either a good or partial clinical response displayed a reduction in the number of colonies or clusters formed by their peripheral blood leukocytes in a double layer agar culture assay following incubation with vincristine. The CFU-C of five of six patients who failed to respond clinically to vincristine and prednisone were not suppressed following incubation with up to 12 μM vincristine. Three additional patients were not evaluable due to early post-treatment deaths. In vitro assay of the effects of vincristine on CFU-C appears to have predictive value for in vivo response in blast crisis of CGL.     

In vitro and in vivo investigations for the development of cytostatic methylhydrazones

Summary In in vitro short-term (3 h) assays, the -chloroethyl-methyl-hydrazones B 1 and B 2 inhibit the uptake of ³H-thymidine by EAC and L 1210 leukemia cells, B 2 being 5 to 10 times more effective than B 1. The growth inhibitory effect of both compounds was also confirmed in long-term (7 days) clonal assays using agar-containing glass capillaries, B 2 again being more effective than B 1. In contrast to these differences in vitro, in vivo both substances showed remission to the same degree in EAC- and complete resistance in L 1210-bearing mice. The diverging in vitro/in vivo sensitivities were thought to result from differences in the affinity of the methylhydrazones to the tumor cells: using short exposure periods (3 h) B 1 was more inhibitory than B 2 on both EAC and L 1210 colony growth; i.e., the more hydrophilic B 2 could more easily be washed off. To further test the idea of different cell membrane affinities, the methylhydrazones ZB 1 and P 1 with increasing lipophilic properties were synthesized. In vitro, after both pulse and continuous exposure ZB 1 and P 1 showed enforced inhibitory effects on colony growth. In vivo, ZB 1 and P 1 reduced the tumor weight of EAC mice, while only P 1 increased the survival time of L 1210 mice. The results suggest that from the combination of in vitro/in vivo assays mechanistic conclusions can be derived that are valuable for further development of these cystostatics.Abbreviations B 1 N-methyl-N--chloroethyl-benzaldehyde-hydrazone - B 2 N-methyl-N--chloroethyl(p-dimethylamino)benzaldehyde-hydrazone - EAC Ehrlich Ascites Carcinoma - FCS fetal calf serum - ³H-dThd 6-³-H-thymidine - L 1210 Leukemia L 1210 - P 1 N-methyl-N--chloroethyl-pentadiene-benzaldehyde-hydrazone - ZB 1 N-methyl-N--chloroethyl-cinnamoylaldehyde-hydrazone     

Antiproliferative activity of liposomal epirubicin on experimental human gliomas in vitro and in vivo after intratumoral/interstitial application

Liposomal epirubicin was prepared using the controlled detergent dialysis method. The entrapment rate was 65.5±6.4%. The mean particle size was 210±38 nm. In vitro, a concentration-dependent antiproliferative activity of free epirubicin was observed. Liposome-entrapped epirubicin was superior to the free drug; the ID₅₀ of the liposomal preparation was about 1.6-fold lower as compared to the free drug. Intratumoral/interstitial (i.t./i.s.) application of liposomal epirubicin was likewise superior to i.t./i.s. application of the free drug.Abbreviation ID₅₀ 50% inhibitory dose (concentration)     

The effects of islet cell surface antibodies on the metabolic function of mouse islet B cells in vitro

Immunoglobulin (Ig) fractions from the plasma of a group of newly diagnosed insulin-dependent diabetes mellitus (type 1) patients and a set of control subjects were assessed for their effects on isolated mouse islet function. It was found that Igs from type 1 patients caused a significant inhibitory effect on insulin secretion when incubated with mouse islets as compared with controls (25.6±2.9 pg islet^–1 h^–1 vs 44.7±7.7 pg islet^–1 h^–1,P<0.05). The plasma samples from which the Igs were obtained were then tested for the presence of antibodies to the mouse islet cell surface (ICSA). Four of the nine patients were positive for ICSA, and plasma samples from eight control subjects were all negative. ICSA-positive samples appeared to have the greatest inhibitory effect on insulin secretion when compared with their respective controls (53.3±7.0 pg insulin islet^–1 min^–1 vs 30.9±3.7 pg insulin islet^–1 min^–1,P<0.05). In contrast, it was also found that ICSA-positive Ig fractions had no significant effect on glucose oxidation when co-incubated with mouse islets as compared with the controls (11.3±2.3 pmol islet^–1 h^–1 vs 11.2±2.9 pmol islet^–1 h^–1). These studies suggest that Igs from newly diagnosed type 1 patients containing ICSA may impair insulin secretion from isolated mouse islets by mechanisms which do not involve the inhibition of B-cell glucose metabolism.     

Effects of indomethacin on the rat small intestinal mucosa: immunohistochemical and biochemical studies using anti-mucin monoclonal antibodies

Background  The luminal surface of the gastrointestinal tract is covered by a viscoelastic gel layer that acts as a protective barrier against the intraluminal environment. Because the situation of the small intestine has not been elucidated to the same degree as other sections, in this study, we investigated the effects of indomethacin on the rat small intestinal mucosa. Methods  Male Wistar rats were given indomethacin 10 mg/kg s-c and sacrificed 1, 3, 7, or 14 days later. The small intestine was opened along the anti-mesenteric side, and examined macroscopically. Total mucin content in the small intestinal epithelium was measured and immunoreactivity was examined using anti-mucin monoclonal antibodies HCM31 and PGM34. Results  Indomethacin caused punched out and linear ulcers located mostly along the mesenteric margin of the distal jejunum with sparing of the ileum. Histological examination showed sialomucin recognized by HCM31 increased on day 3 especially in the regenerating epithelium around the ulcer edge. Furthermore, the surface mucous gel layer displayed a multilaminated pattern, consisting of non-sulfated sialomucin-rich layers and sulfated mucin-rich layers, where both mucins had the common core protein, MUC2. Biochemical measurements also showed the total mucin content of the jejunum increased transiently and HCM31-positive mucin increased approximately 4 times greater than baseline on day 3, but no marked changes were observed in the ileum, with few ulcers observed. Conclusions  Indomethacin administration causes quantitative and qualitative change in jejunal mucin. In particular, sialomucin plays an important role in regenerating epithelium during the healing process following indomethacin-induced mucosal damage.     

Antitumor activity of L-2,4 diaminobuturic acid against mouse fibrosarcoma cells in vitro and in vivo

Summary Mouse fibrosarcoma cells were grown in vitro and incubated with L-2,4 diaminobuturic acid, a non-metabolizable amino acid. The tumor cells were irreversibly and totally damaged by incubation with 10 mM DAB for 24 h at 37 °C. The cell-destructive effect by DAB was probably due to an osmotic lysis induced by the non-saturated intracellular accumulation of DAB. The harmful effect of DAB could be abolished by concomitant incubation with L-alanine and L-methionine, that compete with DAB for the same transport system, while the D-forms of the same amino acids as well as sarcosine had a weak effect.The fibrosarcoma cells were also transplanted s.c. into mice that were subsequently treated with i.p. injections of an isotonic 0.1 M DAB solution. The neoplastic cells were transplanted into totally 90 animals. The mean tumor weight of 42 treated animals was 1.16 g (±0.77 g) compared with the corresponding figures of the 27 untreated mice, that were 2.05 g (±1.22 g), i.e., a 43.4% reduction of tumor growth. There were, however, 17 drug-related deaths. Treatment with DAB generally resulted in weight reduction, at least partly due to loss of appetite, in the animals. In addition, neurological symptoms of a specific character could develop among several of the treated animals. The side effects apparently restrict the usefulness of DAB alone as an anti-tumor agent, but since the principle of action of DAB is unique and not shared by other known chemotherapeutics it might offer new possibilities in the combined treatment of neoplastic growth.

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Abbreviations AIB -aminoisobuturic acid - DAB L-2,4 diaminobuturic acid - MEM minimum essential medium - ld lactic acid dehydrogenase     

Chemoresistance of P. falciparum in urban areas of Yaounde, Cameroon. Part 1: Surveillance of in vitro and in vivo resistance of Plasmodium falciparum to chloroquine from 1994 to 1999 in Yaounde, Cameroon

Chloroquine is indicated for the first-line treatment of uncomplicated malaria in most African countries. However, the spread of chloroquine-resistant Plasmodium falciparum requires periodic monitoring. Between 1994 and 1999, we studied the evolution of chloroquine resistance in adults (aged > 15 years) and children aged 5-15 years by using tests of therapeutic efficacy and in vitro assays. Responses to the 14-day in vivo test were classified according to the new criteria established by the World Health Organization. The results of the semi-microtest and the microtest were expressed as the 50% inhibitory concentration (IC50), and the threshold level of resistance was set at IC50 > 100 nM. The overall percentages of clinical and parasitological failures were 39.7% (31. 3% - 48.1%) and 48.8% (40.2% - 57.4%), respectively. Similarly, the percentage of isolates that were resistant in vitro was 52.5%. During the study, IC50 geometric mean varied between 84,6 nM and 149, 8 nM. The results of the in vitro assays agreed with those of tests of therapeutic efficacy (kappa coefficient = 0.69). The patients' chloroquine plasma levels were measured on day 0, day 3, day 7, and day 14. Drug measurement showed wide inter-individual variations and higher plasma levels in adults than in children. Some cases of therapeutic failure were associated with inadequate plasma levels of chloroquine. Our results confirm the high level of chloroquine resistance in Yaoundé and suggest that the use of an alternative antimalarial drug for the first-line treatment of uncomplicated malaria is warranted.     

多种体外预处理对胰岛移植物免疫原性影响的研究

胰岛移植物经２４℃培养、冷冻保存、激光照射在２４℃培养加冷冻保存等体外预处理后，其胰岛淋巴细胞混合培养（ＭＬＩＣ）的ｃｐｍ值、制备物内ＤＲ阳性细胞数及胰岛内淋巴样细胞数均比对照组明显降低，提示上述预处理可明显降低胰岛移植物的免疫原性，从而可能减少移植物排斥，延长移植物存活。