Kidney transplants in mice. An analysis of the immune status of mice bearing long-term, H-2 incompatible transplants

Kidney transplants between strains of mice which are incompatible at either the K or the D end of the H-2 complex usually function for prolonged periods supporting the lives of nephrectomized recipients. This occurs with no recipient treatment. With multiple H-2 and non-H-2 determined incompatibilities, transplants may be rejected but more slowly than skin grafts. In the strain combination studied most extensively in these experiments (B10.D2 to B6AF(1)) in which the incompatibility was confined to the K end of the H-2 region, about 70 percent of recipients survived for many weeks with normal blood urea nitrogen levels. Skin grafts between untreated members of these strains were rejected promptly (mean survival time of 13.5 +/- 1.1 days) as were kidney transplants to recipients of prior skin grafts. Donor strain skin grafts to recipients of kidney transplants after kidney transplantation enjoyed greatly prolonged survival whereas skin grafts from a third party (A.SW) were rejected normally. If kidney tissue was transferred in the form of free grafts without primary vascular union, it was rejected promptly leaving its recipient highly immunized. Cellular and humoral immunity to donor antigens declined over the first few weeks after transplantation, and the spleens of long-term recipients contained no “killer cells.” Recipient lymphoid cells could mount active graft versus host reactions to donor strain antigens on transfer to neonatal mice. Nevertheless, they were distinctly less able to respond specifically by the production of killer cells to donor strain antigens after sensitization in vitro. No evidence that this defect was associated with the presence of suppressor cells was forthcoming from several types of in vivo and in vitro tests.     

Roles of liposome composition and temperature in distribution of amphotericin B in serum lipoproteins.

The role of liposome composition and temperature in the distribution of amphotericin B (AmB) with serum lipoproteins and the role of particle charge in AmB transfer to serum lipoproteins were determined. Serum obtained from healthy volunteers was incubated with known concentrations of AmB or different liposomal formulations of AmB (1 to 100 micrograms/ml) at 37 degrees C for various time intervals (5, 10, 20, 30, 45, and 60 min). After each interval, serum was removed and separated into high-density lipoprotein (HDL) and low-density lipoprotein (LDL) fractions by an LDL-direct assay. The distribution of AmB (Fungizone) at 5 min through 1 h of incubation at 25 degrees C remained constant and was similar in the HDL and LDL fractions. At 37 degrees C, at 5 through 45 min of incubation, 54 to 61% of AmB was recovered in the HDL fraction; however, at 1 h more than 75% of the AmB concentration was recovered in the HDL fraction. In contrast, 87.5 to 92% AmB was recovered in the HDL fraction throughout the incubation when negatively charged liposomal AmB (dimyristoylphosphatidylcholine [DMPC]:dimyristoylphosphatidylglycerol [DMPG], 7:3 [wt/wt]) was used. With positively charged liposomes, 75 to 87.7% of AmB was recovered in the HDL fraction through the different time points studied. AmB incorporated into DMPC (neutral) and DMPG (negative) liposomes, and AmB was distributed in an HDL:LDL ratio of 6:4 following 1 h of incubation. Ninety percent of AmB and 80% of the lipid were found in the HDL fraction in a 3:1 molar DMPG:AmB ratio and in the LDL fraction in a 6:1 molar ratio. Lipid charge and temperature play a role in AmB distribution into serum lipoproteins. AmB and DMPG may contransfer as an intact drug-lipid complex to serum lipoproteins.     

Physical characteristics and lipoprotein distribution of liposomal nystatin in human plasma.

The physical characteristics and lipoprotein distribution of free nystatin (NYS) and liposomal NYS (L-NYS) in human plasma were investigated. To determine the percentage of NYS that was lipid associated following incubation in human plasma, C18 reverse-phase extraction columns were used. To assess plasma drug distribution, NYS and L-NYS (20 microg/ml) were incubated in human plasma for 5, 60, and 120 min at 37 degrees C. After each interval, plasma was removed and separated into its lipoprotein and lipoprotein-deficient plasma (LPDP) fractions by ultracentrifugation and assayed for NYS by high-pressure liquid chromatography. Further studies evaluated the liposome structure of L-NYS by filtering through a 0.14-microm-pore-size microfilter before and after the addition of human plasma. When reconstituted L-NYS (mean particle diameter +/- standard deviation, 321 +/- 192 nm) was applied to a C18 column, 67% +/- 4% of the initial NYS concentration was associated with the lipid. When plasma samples containing L-NYS that had been incubated for 5 to 120 min at 37 degrees C were applied to C18 columns, 66 to 76% of the NYS was lipid associated. Incubation of NYS in human plasma for 5 min at 37 degrees C resulted in 3% +/- 1% of the initial NYS concentration incubated in the low-density lipoprotein (LDL) fraction, 23% +/- 4% of that in the high-density lipoprotein (HDL) fraction, and 66% +/- 10% of that in the LPDP fraction. In contrast, the distribution of NYS following incubation of L-NYS in human plasma for 5 min was 13% +/- 2% in the LDL fraction, 44% +/- 5% in the HDL fraction, and 42% +/- 5% in the LPDP fraction. Similar results were observed following 60 and 120 min of incubation. In addition, the liposome structure of L-NYS was quickly lost when mixed with plasma. These findings suggest that rapid disruption of the L-NYS structure upon incubation in human plasma is consistent with its rapid distribution in plasma. The preferential distribution of NYS into the HDL fraction upon incubation of L-NYS may be a function of its phospholipid composition.     

Polycystic Kidney Disease Re-evaluated: A Population-based Study

A genetic register of all known cases of autosomal dominantpolycystic kidney disease occurring in South and Mid-Wales hasbeen established. In a population of 2.1 million, 209 familieswith affected members were identified, 303 of whom are currentlyalive, 70 on renal replacement therapy. An additional 551 caseswould be predicted amongst family members at 50 per cent and25 per cent risk, giving an apparent prevalence of 1:2459 inthe general population. Five possible new mutations were seenwhere adults with phenotypic autosomal dominant polycystic kidneydisease had both parents alive, age > 55 years with no cystsvisible on ultrasound. The take-on rate for renal replacementtherapy increased during 1970–79 but has apparently reacheda plateau of 4.8 cases per million population per year overthe last 8 years, despite a rapidly increasing acceptance ofuraemic patients as a whole (72/10⁶/year in 1988–89).Considerably more patients with autosomal dominant polycystickidney disease aged over 50 years were started on treatmentin 1980–89 than in 1970–79, but the survival overallimproved with time. All cases of autosomal dominant polycystickidney disease reaching end-stage renal disease are now beingtreated, but the apparent clinical prevalence of this conditionin our region is less than half the supposed gene frequency,suggesting that undiagnosed cases have a benign prognosis.     

A lipidic delivery system of a triple vaccine adjuvant enhances mucosal immunity following nasal administration in mice

We previously developed an highly efficacious combination adjuvant comprised of innate defense regulator (IDR)-1002 peptide, poly(I:C) and polyphosphazene (TriAdj). Here we aimed to design and test the in vivo efficacy of a mucoadhesive nasal formulation of this adjuvant. To determine the physical properties of the formulation, the effect of addition of each individual component was characterised by gel electrophoresis and fluorescence quenching using rhodamine-poly(I:C). Cationic liposomes comprised of didodecyl dimethylammonium bromide (DDAB), dioleoyl phosphatidylethanolamine (DOPE) (50:50 or 75:25?mol:mol) and DDAB, L-α-phosphatidylcholine (egg PC) and DOPE (40:50:10?mol:mol:mol) were prepared by the thin-film extrusion method. The liposomes and TriAdj were combined by simple mixing. The formed complex (L-TriAdj) was characterized by dynamic light scattering, zeta potential, and mucin interactions. We found that IDR-1002 peptide, polyphosphazene and poly(I:C) self-assembled in solution forming an anionic complex. Exposure of RAW267.4 mouse macrophage cells to TriAdj alone vs. L-TriAdj indicated that DDAB/DOPE (50:50) and DDAB/EPC/cholesterol (40:50:10) complexation reduced TriAdj toxicity. Next, TriAdj-containing cationic liposomes were prepared at several molar ratios to determine optimal size, stability and desired positive charge. Transmission electron microscopy showed rearrangement of lipid structures on binding of liposomes to TriAdj and to mucin. Stable particles (<200?nm over 24?h) showed mucin binding of DDAB/DOPE?+?TriAdj was greater than DDAB/EPC/DOPE?+?TriAdj. To verify in vivo efficacy, mice were administered the DDAB/DOPE?+?TriAdj complex intranasally with ovalbumin as the antigen, and the immunogenic response was measured by ELISA (serum IgG1, IgG2a, IgA) and ELISpot assays (splenocyte IL-5, IFN-γ). Mice administered adjuvant showed a significantly greater immune response with L-TriAdj than TriAdj alone, with a dose-response proportionate to the triple adjuvant content, and an overall balanced Th1/Th2 immune response representing both systemic and mucosal immunity.     

微创经皮钢板置入内固定治疗胫腓骨骨折的技术操作特点

目的:总结微创经皮钢板置入内固定治疗胫腓骨骨折的技术操作特点,并观察材料及宿主反应。方法:2004-06/2006-10在济宁医学院附属金乡医院对18例胫腓骨骨折患者在微创手术下进行了手术置入内固定材料。男13例,女5例,年龄17～73岁。术后按Johner-Wruhs方法评价测试各大关节功能,分为优、良、中、差。全部病例进行临床随访。术前、术后1周、6周、3个月、半年及1年分别摄X线片与健侧对比测量患肢外观、成角、旋转和短缩情况,并观察材料及宿主反应。结果:①本组病例切口均顺利愈合,术后3～14d出院。②全部获得随访,平均随访时间14个月;骨愈合时间3～10个月。③按Johner-Wruhs方法评价功能,优13例,良4例,中1例,差0例,以优良为满意标准,本组病例总体满意率94.4%。④术后1例出现跛行步态,中度疼痛,骨成角畸形15°,可能因为患者对不锈钢材料有排斥反应造成固定不牢所致。结论:微创经皮钢板置入内固定材料治疗胫腓骨骨折具有手术创伤小、骨折愈合快、功能恢复好的特点;内固定材料未出现特殊材料反应与宿主反应。     

Cholesterol as a Potential Target for Castration-Resistant Prostate Cancer

Advanced prostate cancer (CaP) is often treated with androgen deprivation therapy (ADT). Despite high initial success rates of this therapy, recurrence of the cancer in a castration-resistant (CRPC) form is inevitable. It has been demonstrated that, despite the low levels of circulating androgens resulting from ADT, intratumoral androgen levels remain high and androgen receptor activation persists. Recently, it was discovered that de novo androgen synthesis is occurring within the tumor cells themselves, thus providing a potential mechanism for the high endogenous concentrations. A common upstream precursor in this steroidogenic pathway is cholesterol. For many decades, the breakdown of cholesterol homeostasis in cancer has been the focus of research, but this was largely to elucidate its involvement in maintaining membrane integrity and cell signaling. De novo steroidogenesis has provided a new avenue for cholesterol research and reinforces the importance of understanding the mechanisms that lead to the alterations in cholesterol regulation in the progression to CRPC. The findings to date suggest that cholesterol homeostasis is altered to support de novo androgen synthesis and appear to facilitate disease progression. We further propose that a better understanding of the link between cholesterol and de novo androgen synthesis in CaP progression may provide opportunities for novel therapeutic intervention, namely via eliminating sources of the precursor cholesterol. This review summarizes the implications of cholesterol dysregulation in CaP and particularly in the post-ADT castration-resistant state, as well as the potential implementation of novel therapies targeting these cholesterol sources.     

Retrospective Study on Efficacy of Intermaxillary Fixation Screws

Background

We evaluated the efficacy of intermaxillary fixation (IMF) screws in the treatment of mandibular fractures.

Methods

Two hundred patients with mandibular fractures, treated by IMF using these screws, were evaluated by pre and postoperative panoramic radiographs. Clinical testing was carried out for vitality and abnormal mobility of teeth adjacent to the site of screw insertions. Other factors such as possible iatrogenic dental injuries, loss, breakage or screw cover by oral mucosa and postoperative occlusion were also studied.

Result

The most important complication noticed was iatrogenic damage to dental roots.

Conclusion

Use of intraoral cortical bone screws for IMF is a valid alternative to arch bars in the treatment of mandibular fractures. Iatrogenic injury to dental roots is the commonest problem which can be minimized by an experienced surgeon.Key Words: Intermaxillary fixation, Bone screws, Mandibular fractures, Iatrogenic injury