Detection of both isotypes of complement C4, C4A and C4B, in normal human glomeruli

Monoclonal antibodies reactive against the complement C4A and C4B isotypic components were used in an immunoperoxidase technique for the histological study of normal human renal tissue. Prominent staining with both antibodies was seen in the mesangial areas of all normal kidney sections investigated. Occasional staining of arteriolar walls of the same tissues, however, was also observed. In contrast, no mesangial staining was seen using monoclonal antibodies reactive against other 'early' complement components, such as C1q and C3. Specificity of the glomerular staining with the anti-C4 reagents was demonstrated in two patients possessing only the C4A serum component but lacking genetically the C4B locus products. As would be predicted, glomerular staining with the anti-C4A reagent, but not anti-C4B, was clearly demonstrable. It is concluded that both isotypes of complement C4 are present in normal human glomeruli and thus might be operative for normal mesangial function.     

Ganglioneuroma of the C4, C5 interspace

Neurogenic tumors in the neck region are relatively infrequent with the exception of those involving the cranial nerves. A case of a ganglioneuroma or neurofibroma involving the nerve root of C4, C5 interspace is reported. The tumor appeared as a mass within the neck with a slight amount of pain in the shoulder and upper arm upon palpation. Surgical exploration revealed a mass superficial to the foramen and erosion of the foramen. Roentgenograms taken in the region demonstrated an extradural mass that was subsequently removed by laminectomy. Postoperatively, the patient did quite well. Surgical excision is the treatment of choice. Preservation of the nerve should be accomplished if at all possible.     

Effects of leukotrienes B4, C4, and D4 on rat mesenteric microcirculation

Arachidonic acid is metabolized to leukotriene (LT) B4, C4, D4, and E4 by lipoxygenase. LTB4 is a chemotactic agent while LTC4 and LTD4 stimulate smooth muscle fibers to contract. Mesenteric vessels have the capacity to release leukotrienes. The possibility that leukotrienes might be responsible for or contribute to mesenteric ischemia during mesenteric low flow, embolism, and thrombosis prompted us to investigate their action on mesenteric vessels. LTB4, C4, and D4 were applied topically on small bowel mesentery of 22 Sprague-Dawley rats in sequentially increasing concentrations. Mesenteric arterioles with diameters of 8-20 microns were observed through a microscope and vessel diameters were measured using a video shear monitor. LTB4 had no effect on diameter, but doses as low as 3 X 10(-8) M induced white blood cell adherence to venular endothelium, reflecting the potent chemotactic properties of this compound. LTC4 and D4 had no effect on systemic blood pressure or white blood cell adherence. Applications of 6.4 X 10(-9), 3.2 X 10(-8), and 6.4 X 10(-8) M LTC4 decreased mesenteric arteriolar diameter to 85.3* +/- 4.7% (mean +/- SD), 75.7* +/- 7.5%, and 66.8* +/- 6.1% of baseline, and 4 X 10(-9), 2 X 10(-8), and 4 X 10(-8) M LTD4 decreased diameter to 84.9* +/- 6.1%, 75.1* +/- 4.2%, and 64.1* +/- 5% of baseline, respectively (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Complement (C3, C4) Consumption in Cardiopulmonary Bypass,Cardioplegia, and Protamine Administration

Anaphylatoxins produced by complement activation have been postulated to be responsible for postperfusion syndrome and protamine hypotension in patients undergoing cardiac surgical procedures. The consumption of serum complement components C3 and C4, which reflects the classic and alternate pathway activations of the complement system, was studied in 22 patients undergoing cardiac operations. Prior to the onset of cardiopulmonary bypass, the complement levels were within normal range. Rapid reduction in both C3 and C4 within minutes of cardiopulmonary bypass indicated rapid complement activation. Such a reduction in complement levels could not be accounted for by either hemodilution or transfusion of complement-poor blood. Aortic cross-clamping and cold potassium cardioplegia followed by myocardial reperfusion did not lead to further consumption of C3 and C4. Slow intravenous infusion of protamine sulfate after cardiopulmonary bypass did not change C3 and C4 levels significantly in our patients, although protamine and heparin-protamine complex have been shown to activate complement components in vitro.In another group of 9 similar cardiac surgical patients, C3 and C4 were found to return to normal levels within 24 hours after operation. This study thus confirms the rapid activation of the complement system by cardiopulmonary bypass but fails to demonstrate further activation of the complement system by cardioplegia or protamine administration.     

Studies of monkey complement: measurement of cynomolgus monkey CH50, ACH50, C4, C2 and C3

Abstract: Background: The cynomolgus monkey is commonly used as the recipient in transplantation experiments. However, study of the complement system of cynomolgus monkeys is lacking. In the present study, the complement system of cynomolgus monkeys was compared with that of humans, by checking hemolytic titers. Methods: Hemolytic titers of complement from cynomolgus monkeys were calculated using the same methods as are used in humans. The complement regulatory function of human decay accelerating factor (DAF, CD55) in cynomolgus monkey serum was next studied using erythrocytes from human DAF‐transgenic pigs. Results: The results indicated relatively high values, except for C4: CH50: 211.19 ± 42.78 units/ml, ACH50: 51.47 ± 12.43 units/ml, C4: 30 170 ± 14 300 SFU/ml C2: 33831 ± 7442 SFU/ml and C3: 93612 ± 30131 SFU/ml. Western blot experiments using antibodies for human complement components revealed similarities between the cynomolgus monkey and human complement systems. Human DAF inhibited pig erythrocyte lysis from approximately 60–70% to 17% in both human and cynomolgus monkey sera, indicating an almost identical complement regulatory function. Conclusion: The hemolytic titer of cynomolgus monkeys was greater than the titer measured in human serum. However, human DAF showed nearly the same complement regulatory function in both human and cynomolgus monkey sera.     

Abbreviated mycophenolic acid AUC from C0, C1, C2, and C4 is preferable in children after renal transplantation on mycophenolate mofetil and tacrolimus therapy

In order to allow a similar algorithm to be used for both adults and children on tacrolimus-based and mycophenolate mofetil [MMF, a pro-drug for mycophenolic acid (MPA)]-based immunosuppression, a limited sampling technique from the trough level (C0) and the levels 30 min (C0.5) and 2 h (C2) after intake was to be developed from MPA area under the time–concentration curves (AUC). We retrospectively analyzed 49 full ten-point pharmacokinetic (PK) profiles from 29 pediatric patients on MMF and tacrolimus. We used stepwise multiple regression analysis to calculate limited sampling approaches. Agreement with the AUC was tested by means of Bland and Altman analysis. The correlation between AUC and pre-dose trough concentration was r²=0.5188 (P<0.0001) and between AUC and post-dose trough concentration r²=0.6924 (P<0.0001). The next best correlations were with 2 h (C2, r²=0.6711, P<0.0001), 4 h (C4, r²=0.6411, P<0.0001), 1.5 h (C1.5, r²=0.6344, P<0.0001), and 6 h (C6, r²=0.6219, P<0.0001). Three-point estimates at C0, C0.5, and C2 resulted in an acceptable correlation between predicted AUC and AUC from the full profile when we used the formula AUC = 10.01391+3.94791×C0+3.24253×C0.5+1.0108×C2, Pearsons r=0.8996, 95% confidence interval 0.8277–0.9424. However, even better results could be obtained when we used AUC = 8.217+3.163×C0+0.994×C1+1.334×C2+4.183×C4, Pearsons r=0.9456, 95% confidence interval 0.9051–0.9691. Bland and Altman analysis revealed good agreement between AUC predicted from C0, C0.5, and C2 and AUC from the full profile, but was inferior to the four-point approach. Also, the previously reported formula derived for adults was not usable in these patients. A special formula must be used for children. The AUC of MPA can be predicted by limited sampling including C0, C0.5, and C2, while an approach using C0, C1, C2, and C4 is preferable.     

Comparative effects of inhaled leukotriene C4, leukotriene D4, and histamine in normal human subjects.

The comparative actions of inhaled leukotriene C4 (LTC4), leukotriene D4 (LTD4), and histamine were studied in six normal subjects. LTC4 and LTD4 were shown to be more potent bronchoconstrictors than histamine, with a more sustained action. LTC4 and LTD4 caused wheezing without cough or throat irritation and were shown to act on large and small airways.     

颈3椎板颈7上半椎板切除及颈4～6椎管扩大成形术的临床初步应用

目的通过对多节段脊髓型颈椎病、颈椎后纵韧带骨化症、颈椎外伤患者行"C3椎板切除、C7上半椎板切除、C4~6椎管扩大成形术"治疗,探讨颈椎病的创新手术治疗方法。方法对84例多节段脊髓型颈椎病、颈椎后纵韧带骨化症、颈椎外伤患者进行颈椎正、侧位及动力位X线片、椎管造影、CT、CTM、MRI等检查,明确诊断,确定有手术指征后,行"C3椎板切除、C7上半椎板切除、C4~6椎管扩大成形术"治疗。结果本组83例获得3~24个月的随访,平均14.7个月,患者均有比较满意的功能恢复,术前平均JOA评分7.05分,术后平均9.1分,末次复查时平均JOA评分10.38分。植入人工骨位置理想,愈合满意。出现C5神经根牵拉、轴性疼痛等并发症,经处理后逐渐恢复。结论 "C3椎板切除、C7上半椎板切除、C4~6椎管扩大成形术",手术方法简便,适于掌握,手术时间短、出血少,预后好,患者恢复快,是一种术式合理并方便推广应用的治疗方法。     

Mesangial glomerulonephropathy with decreased circulating C4 and predominant mesangial C4 deposition in association with one null gene at the C4B locus

We report a case of mesangial glomerulonephropathy associated with decreased circulating C4 in a young man with recurrent microscopic hematuria and one null gene at the C4B locus. Mesangial deposits moderately reactive with anti-C4 and weakly reactive with anti-C3 and anti-IgA were found on renal biopsy. No evidence was found to support a diagnosis of IgA nephropathy or any other of the recently described mesangial glomerulonephropathies with immunoglobulin and complement deposition. This case apparently represents a unique, heretofore undescribed variant of mesangial glomerulonephropathy associated with mesangial C4 deposition and C4 hypocomplementemia.     

Leukotriene C4 and D4 contract rat glomerular mesangial cells

The sulfidopeptide leukotrienes, LTC4 and LTD4, have vasoconstrictor effects in the kidney, reducing both renal blood flow and the glomerular filtration rate. As one mechanism regulating the glomerular filtration rate, mesangial cell contraction may reduce the capillary surface area, thereby lowering the ultrafiltration coefficient. Using image analysis microscopy to quantify changes in cell morphology, we found that LTC4 and LTD4 (1 X 10(-12)M to 1 X 10(-6)M) reduced the cross-sectional area of cultured mesangial cells from rat glomeruli. The response to LTC4 and LTD4 (10(-6)M), as measured by the percentage of responding cells (30 to 35%), the maximum decrease in cross-sectional area (25 to 32%), and the time course was identical to that for angiotensin II (10(-6)M). The contraction induced by LTD4 was attenuated by an LTD4 receptor antagonist (4R,5S,6Z-nor-LTD1). Also, preincubation with colchicine prevented LTC4-induced contraction. Leukotriene B4, a non-sulfidopeptide leukotriene that stimulates chemotaxis and chemokinesis, had negligible agonist activity. Mesangial cells cultured on less adhesive teflon membranes were more responsive to LTD4 (62% of cells responded) than cells cultured on glass or polystyrene (35% of cells responded). Mesangial cell contraction was not merely a shape-change as a result of cell damage, since cellular injury was not documented by lactate dehydrogenase release and proliferation of mesangial cells was not retarded by LTC4. Furthermore, the contraction was independent of cell size. Because leukotrienes stimulate cyclooxygenase products in other cells, we examined the ability of the sulfidopeptide leukotrienes to stimulate prostaglandin and thromboxane synthesis. LTC4 and LTD4 did not stimulate PGE2 formation, the major cyclooxygenase product of rat mesangial cells.(ABSTRACT TRUNCATED AT 250 WORDS)     

Characterization of CD4, CD8, CD56 positive lymphocytes and C4d deposits to distinguish acute cellular rejection from recurrent hepatitis C in post-liver transplant biopsies

INTRODUCTION: Hepatitis C viral (HCV) infection is the most common cause for liver transplantation (LTx) in USA. Hepatitis C viral recurrence in liver allograft is almost universal, which is often difficult to distinguish from acute cellular rejection (ACR). AIM: Aim of the present study is to examine the differences between distribution of CD4, CD8, CD56 positive lymphocytes, and C4d deposits in patients with ACR and recurrent HCV. PATIENTS AND METHODS: As a pilot project, a group of five post-LTx HCV RNA negative patients, strongly suspicious for ACR based on clinical findings and history of medication non-compliance and another group of five post-LTx HCV positive, medication compliant patients with abnormal liver function were retrospectively selected. Liver biopsies of these patients were stained with monoclonal CD4, CD8, CD56, and polyclonal C4d antibodies and compared. RESULTS: Mean CD4, CD8, and CD56 counts in ACR group were 156.7 +/- 17.6, 35.4 +/- 8.8, and 1.0 +/- 1.8/HPF, respectively and were 89.7 +/- 41.3, 20.3 +/- 23.2, and 0.6 +/- 0.9/HPF, respectively in HCV recurrence group. Biopsies of four of five patients with ACR demonstrated moderate to strong C4d staining, whereas all patients with recurrent HCV had none to mild C4d staining. CONCLUSION: Mean CD4, CD8, and CD56 were similar for acute rejection and recurrent HCV infection. However, 80% of patients with ACR showed moderate to strong staining for C4d and all recurrent HCV patients showed none to mild C4d staining.     

Role of leukotrienes B4 and C4 in liver allograft rejection

Previous studies have shown that eicosanoids may act in vitro as immunoregulatory substances. In this study, the concentrations of leukotriene B4 (LTB4) and leukotriene C4 (LTC4) were measured in a model of allograft rejection. Six orthotopic allotransplants of the liver were performed in dogs without the administration of immunosuppressives. LTB4 levels showed an increase coinciding with the start of rejection, significant differences being present between the basal levels and those measured 24 h post-revascularization (P < 0.05), and every day from the 3rd postoperative day (P < 0.01). LTB4 rose before the parameters generally used in evaluating rejection. LTC4 levels increased significantly (P < 0.001) in the first 24 h, and experienced no further variations. LTB4 may play an important role in the mechanisms which bring about the response to the allograft. This substance could be a specific and early marker for rejection.