Calcium phosphate ceramics as bone graft substitutes in filling bone tumor defects

Background:

Synthetic bio-inert materials are currently used as an alternative to autogenous bone graft. Calcium hydroxyapatite (HA) and Beta tri-calcium phosphate (β-TCP), which belong to the calcium phosphate ceramics group, are biocompatible and osteo-conductive. The purpose of this study is to analyse the use of HA and β-TCP in their ceramic forms as a bone graft substitute in filling bone voids after curettage of benign bone tumors.

Materials and Methods:

Twenty-four patients in the age range of 3.5-55 years (mean 14.3 years) having benign bone tumors with bone defects were filled with bone graft substitute following curettage. In 20 patients bone defects were filled with block/granules of HA ceramic and in four with β-TCP. Fibular strut graft was packed with HA in four patients. The patients were followed up for an average of 18 months (range 12-36 months).

Results:

The functional status of the patients at follow-up was evaluated and compared with preoperative functional status. Early incorporation of graft substitutes became evident radiologically between 6 and 10 weeks (Stage I). Complete incorporation (Stage III) was observed in an average of nine months (6-18 months). Clinical healing was observed before radiological healing. The average time taken to return to preoperative function was 14 weeks. There was no recurrence of lesion or growth retardation.

Conclusion:

Calcium hydroxyapatite and β-TCP are excellent bone graft substitutes for autogenous bone graft in filling voids after curettage of benign bone tumors.     

Comparison of the role of complement in immunity to Schistosoma mansoni in rats and mice.

In vivo depletion of C3 with cobra venom factor (CoF) was used to demonstrate the participation of complement in the innate immunity to S. mansoni and in the acquired immunity of both actively and passively immunized rats. Complement was shown to play an important role in innate immunity, being more involved later in larval migration (Days 8-13 post-infection) than at earlier times (Days--1-3 and Days 3-8 post-infection). Furthermore, the specific component of immunity conferred by immune serum transferred at the lung-migration stage also required complement for optimal expression. This supports the notion that both innate and acquired immunity act not against the much studied early post-penetration stages, but primarily against the lung stages. Although decomplementation at earlier stages of parasite migration (up to 3 days post-infection) did cause some reduction of innate immunity, there was no evidence of any effect on the levels of resistance actively induced by exposure to irradiated cercariae. This suggests that, while complement may play a role in innate immunity during the skin-migration phase, specific complement-mediated attrition does not play a crucial role at this time. The situation was very different in the mouse model, since no involvement of complement in either innate or irradiated vaccine-induced immunity could be demonstrated within the first 15 days of infection. Thus, there appear to be phases in the parasite migration in rats, but not in mice, during which complement becomes a critical factor in both innate and acquired immunity to S. mansoni.     

The natural history of anterior cruciate ligament reconstruction using patellar tendon autograft

The purpose of this study was to review the results of ACL reconstruction using a patellar tendon graft placed ‘over the top’ plus a Macintosh lateral tenodesis, examining changes in knee laxity and functional status with increasing time. There were 74 patients operated on over an 11 year period, and divided into four groups for analysis according to postoperative time. There was a significant and progressive increase in side-to-side laxity difference with time, although functional status did not change significantly, indicating a lack of correlation between objective clinical tests and subjective findings. The highest Lysholm, Tegner and IKDC scores were at 4–5 years after operation, when 60% of patients were at their pre-injury level of sports activity. However, there was always a very significant difference between actual and desired Tegner activity levels for the group as a whole. While there was a significant correlation between degenerative changes and the time between injury and reconstruction, there was no correlation with postoperative time: this provides evidence that ACL reconstruction can protect the knee from later degeneration.     

Enumeration of T and B lymphocytes in whole peripheral blood: absence of a null cell population.

Alkaline phosphatase-labelled F(ab')2 polyvalent anti-human immunoglobulin stained a mean of 12% (s.d. 4.2) of lymphocytes in the whole peripheral blood of 15 normal individuals. However, when the sensitivity of detection of the bound anti-immunoglobulin reagent was enhanced by adding complexes of alkaline phosphatase with F(ab')2 anti-alkaline phosphatase, a mean of 22.1% (s.d. 7.8) of lymphocytes were positive. The mean number of T lymphocytes demonstrated in the same blood samples using a monoclonal anti-T lymphocyte antibody (OKT3) was 78% (s.d. 4.1) and was not increased by immunoenzyme enhancement. In five individuals the blood was washed at 37 degrees C to remove passively adsorbed IgG and was then studied using the enhanced method together with monoclonal anti-kappa and anti-lambda antibodies. The mean +/- s.d. number of kappa-positive lymphocytes was 15.5 +/- 4.6% and lambda-positive was 7.9 +/- 1.1%. The sum of these was the same as the number of cells stained either with anti-kappa and anti-lambda together or with the conventional polyvalent anti-immunoglobulin, confirming that the enhancement procedure was detecting integral membrane immunoglobulin and not passively adsorbed IgG. Application to the same blood sample of both the anti-T cell antibody and the enhancement procedure with polyvalent anti-immunoglobulin stained 99-100% of lymphocytes. The present observations confirm that there are two populations among the B-lymphocytes, the B-major cells with readily demonstrable surface immunoglobulin and the B-minor cells on which surface immunoglobulin is demonstrable only by very sensitive techniques (Haegert & Coombs, 1979). The B-major and B-minor cells together account for all the non-T lymphocytes and there are virtually no so-called 'null' cells in normal peripheral blood. These findings have significant implications for the use of surface membrane immunoglobulin as a marker in the typing of normal and abnormal lymphocyte populations.     

Evaluating patients with renal failure for renal artery stenosis with gadolinium-enhanced magnetic resonance angiography

The incidence and prevalence of end-stage renal disease (ESRD) continues to increase, especially in the elderly population. The role of renovascular disease in contributing to ESRD is still not well defined. The objective of this study was to determine the utility of gadolinium (Gd)-enhanced magnetic resonance angiography (MRA) in evaluating elderly patients with renal insufficiency for renal artery stenosis (RAS). A 7-month prospective study conducted in a tertiary referral center evaluated 40 consecutive patients with progressive renal insufficiency (18 men and 22 women; mean age, 70 +/- 5.6 [standard deviation] years) and high clinical suspicion for renovascular disease with Gd-enhanced MRA. Digital subtraction angiography (DSA) was obtained in only those patients with significant RAS detected by MRA. Twelve patients had significant RAS. Six of these patients had percutaneous transluminal renal angioplasty (PTRA), five patients had renal artery bypass surgery, and one patient had a stent placed after PTRA. Seventy-eight renal arteries were satisfactorily evaluated by MRA. Twenty-two renal arteries were evaluated by both MRA and DSA. Of the 12 significant stenoses detected by the MRA, 11 were confirmed by DSA and 1 was confirmed at the time of surgical revascularization. It is concluded that Gd-enhanced MRA is a useful test for the evaluation of RAS in patients with compromised renal function.     

4-O-卤代酰基-4′-去甲基表鬼臼毒素类似物的合成与抗肿瘤活性

为考察4′-去甲表鬼臼毒素C₄位上联结含卤素原子的酯化侧链时对化合物抗肿瘤活性的影响,设计并采用选择性酯化方法合成了9个新的4′-去甲基表鬼臼毒素酯化产物。其中标题化合物在L₁₂₁₀白血病肿瘤细胞与KB细胞的体外生长抑制试验中普遍表现出显著的抑制活性,大部分化合物活性超过依托泊甙。而普通脂酸酯的活性较弱。