Overexpression of anti-apoptotic Mcl-1 in testicular germ cell tumours

AIMS

To determine the expression of Mcl-1 in testicular germ cell tumours in order to clarify the role of this anti-apoptotic factor in these tumours. Various members of the Bcl-2 family have been implicated in the apoptotic mechanisms regulating germ cell apoptosis. Mcl-1 is an anti-apoptotic Bcl-2 family member and has recently been reported to be related to the progression of malignancy; however, the involvement of Mcl-1 in the development of germ cell tumours is still unknown.

METHODS AND RESULTS

Mcl-1 expression in testicular germ cell tumours was investigated by immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR). By immunohistochemistry, overexpression of Mcl-1 was present in all germ cell tumours that were studied, including embryonal carcinoma and yolk sac tumour, as well as choriocarcinoma and teratoma. In teratomas, Mcl-1 was widely distributed in the epithelial, myogenic, neural and mesenchymal components. RT-PCR analysis after microdissection revealed high levels of Mcl-1 mRNA in all tumour variants compared with non-neoplastic germ cells.

CONCLUSION

Overexpression of anti-apoptotic Mcl-1 may function to enhance the viability of testicular germ cells, thereby leading to tumorigenesis.

High Temperature Characteristics and Solidification Microstructures of Dental Metallic Materials: Part III Alloys for Metal-bond Porcelain

The thermal expansion rate, coefficient of thermal expansion, and high temperature strength of two types of commercially available alloy for metal-bond porcelain, KIK-HII (KIK) and Degubond-J2 (J2), were evaluated up to the liquidus point temperature using a thermo-mechanical analyzer. Furthermore, microstructure in the solid-liquid coexisting region was observed for evaluation. Our results revealed the following findings: 1. For KIK, solidus point was 1,209.3 +/- 3.2 degrees C, liquidus point was 1,308.3 +/- 7.10 degrees C, and melting expansion rate was 0.41+/- 0.16%. 2. For J2, solidus point was 1,198.3 +/- 0.6 degrees C, liquidus point was 1,253.0 +/- 4.4 degrees C, and melting expansion rate was 4.50 +/- 0.80%. 3. At high temperature, the mechanical characteristics of KIK greatly differed from those of J2. The risk of causing deformation during porcelain baking was suggested for KIK. Removal of segregation during casting was considered difficult in J2.

Dolomite supplementation improves bone metabolism through modulation of calcium-regulating hormone secretion in ovariectomized rats

Dolomite, a mineral composed of calcium magnesium carbonate (CaMg (CO3)2), is used as a food supplement that supplies calcium and magnesium. However, the effect of magnesium supplementation on bone metabolism in patients with osteoporosis is a matter of controversy. We examined the effects of daily supplementation with dolomite on calcium metabolism in ovariectomized (OVX) rats. Dolomite was administered daily to OVX rats for 9 weeks. The same amount of magnesium chloride as that supplied by the dolomite was given to OVX rats as a positive control. Histological examination revealed that ovariectomy decreased trabecular bone and increased adipose tissues in the femoral metaphysis. Dolomite or magnesium supplementation failed to improve these bone histological features. Calcium content in the femora was decreased in OVX rats. Neither calcium nor magnesium content in the femora in OVX rats was significantly increased by dolomite or magnesium administration. Urinary deoxypyridinoline excretion was significantly increased in OVX rats, and was not affected by the magnesium supplementation. Serum concentrations of magnesium were increased, and those of calcium were decreased, in OVX rats supplemented with dolomite or magnesium. However, there was a tendency toward decreased parathyroid hormone secretion and increased calcitonin secretion in OVX rats supplemented with dolomite or magnesium. Serum 1,25-dihydroxyvitamin D(3) and osteocalcin levels were significantly increased in the supplemented OVX rats. These results suggest that increased magnesium intake improves calcium metabolism in favor of increasing bone formation, through the modulation of calcium-regulating hormone secretion.

Viral Infections in Juvenile Myelomonocytic Leukemia: Prevalence and Clinical Implications

OBJECTIVES

Viral infections may complicate the diagnosis of juvenile myelomonocytic leukemia (JMML) in a substantial proportion of patients, but this possibility has not been tested in a prospective study. The authors therefore measured the cellular expression of the MxA protein, a reliable marker of viral infection, at diagnosis in children with JMML to estimate the prevalence of such infections.

METHODS

Eighteen children, aged 1 to 69 months, who met the diagnostic criteria of the International JMML Working Group were prospectively studied. MxA expression was assessed by flow cytometric analysis of peripheral blood mononuclear cells stained with an antihuman MxA antibody. All data were obtained through the MDS Committee of the Japanese Society of Pediatric Hematology.

RESULTS

Twelve patients (67%) had elevated levels of the MxA protein, with rotavirus, RS virus, or CMV infection documented in three of these patients. Although none of the patients had primary Epstein-Barr virus (EBV) infection, reactivation of the virus was strongly suspected in four children, including two with monosomy 7, each having increased levels of MxA. Southern blot analysis revealed monoclonal integration of the EBV genome into bone marrow mononuclear cells from one of these patients. There was no discernible correlation between increases in the marker protein and the presenting features or course of the disease.

CONCLUSIONS

Viral infection may be present in two thirds of children with newly diagnosed JMML, but it does not constitute a basis for revising clinical management. The possibility that EBV or other viruses contribute to JMML pathogenesis by stimulating pre-exiting malignant clones warrants further investigation.

Viral infections in juvenile myelomonocytic leukemia: prevalence and clinical implications

OBJECTIVES

Viral infections may complicate the diagnosis of juvenile myelomonocytic leukemia (JMML) in a substantial proportion of patients, but this possibility has not been tested in a prospective study. The authors therefore measured the cellular expression of the MxA protein, a reliable marker of viral infection, at diagnosis in children with JMML to estimate the prevalence of such infections.

METHODS

Eighteen children, aged 1 to 69 months, who met the diagnostic criteria of the International JMML Working Group were prospectively studied. MxA expression was assessed by flow cytometric analysis of peripheral blood mononuclear cells stained with an antihuman MxA antibody. All data were obtained through the MDS Committee of the Japanese Society of Pediatric Hematology.

RESULTS

Twelve patients (67%) had elevated levels of the MxA protein, with rotavirus, RS virus, or CMV infection documented in three of these patients. Although none of the patients had primary Epstein-Barr virus (EBV) infection, reactivation of the virus was strongly suspected in four children, including two with monosomy 7, each having increased levels of MxA. Southern blot analysis revealed monoclonal integration of the EBV genome into bone marrow mononuclear cells from one of these patients. There was no discernible correlation between increases in the marker protein and the presenting features or course of the disease.

CONCLUSIONS

Viral infection may be present in two thirds of children with newly diagnosed JMML, but it does not constitute a basis for revising clinical management. The possibility that EBV or other viruses contribute to JMML pathogenesis by stimulating pre-exiting malignant clones warrants further investigation.

High temperature characteristics and solidification microstructures of dental metallic materials. Part II. ADAS Type 3 gold alloy

Previously, high temperature properties of the silver-palladium-copper-gold alloy were investigated. In this study, the thermal expansion percentage and coefficient, and high temperature strengths of ADAS Type 3 gold alloy were investigated up to the liquidus temperature. Furthermore, microstructural and compositional changes in the solid/liquid dual phase were studied. The following conclusions were obtained. (1) The solidus point of the Type 3 gold alloy was 899.3+/-11.7 degrees C, and the liquidus point was 962.3+/-2.4 degrees C. (2) The thermal expansion percentage at the solidus point was 1.636+/-0.046%, while it was 4.853+/-0.213% for the liquidus point. The thermal expansion percentage of the melt was 3.217+/-0.257%. (3) The melt expansion was observed even under the measuring pressure of 373.75 HPa, which was quite different from the fact that the melt expansion disappeared at the pressure of 20.87 HPa for the silver-palladium-copper-gold alloy. (4) The morphology of solid phase in the solid/liquid dual zone of this alloy was quite different from those observed with the silver-palladium-copper-gold alloy.

Two common founder mutations of the fanconi anemia group G gene FANCG/XRCC9 in the Japanese population

Fanconi anemia (FA) is a rare autosomal recessive disorder of hematopoiesis with eight complementation groups (FA-A, B, C, D1, D2, E, F and G). To date, seven of the FA genes have been identified. Although extensive analyses in Western countries revealed that the subgroup prevalence and mutational spectrum vary depending on the ethnic background, not much data is available on Asian populations. In the present study, 45 unrelated FA families in Japan were screened for FA gene mutations and 10 families with biallelic pathogenic mutations of FANCG/XRCC9, the gene for FA-G, were identified. A splice mutation IVS3+1G>C was detected in all 9 Japanese families, among whom 4 were homozygous and 5 were heterozygous. Among the heterozygotes, three carried 1066C>T in the second allele. In addition, a family homozygous for 1066C>T with Korean ethnicity was identified. Haplotype analysis by means of 9 microsatellite markers spanning the FANCG locus indicates that IVS3+1G>C and 1066C>T are in complete association with distinct ancestry haplotypes. Our data suggest that IVS3+1G>C arose in the Japanese ancestors at a relatively early time, whereas 1066C>T later on migrated from Korea. The two founder mutations with distinct origins account for most of FANCG mutant alleles in the Japanese population.

Tunica interna endothelial cell kinase expression and hematopoietic and angiogenic potentials in cord blood CD34+ cells

Tunica interna endothelial cell kinase (TEK) is expressed in both hematopoietic and endothelial cells and plays a crucial role in hematopoiesis and angiogenesis in mouse development. In humans, however, little is known about the hematopoietic and angiogenic potentials of TEK-expressing cells in umbilical cord blood (CB) cells, which originate during the human fetal period. We therefore compared the hematopoietic and angiogenic abilities of CB CD34+TEK+ and CD34+TEK- cells by using a clonogenic assay and xenotransplantation into immunodeficient NOD/SCID mice. The results showed that colony-forming cells and cells capable of repopulating in NOD/SCID mice were present in both CD34+TEK+ and CD34+TEK- cells and that the hematopoietic activities of the cell types were similar. In contrast, the potential to differentiate into endothelial cells in vivo was greater in the CD34+TEK+ cells. All NOD/SCID mice engrafted with CD34+TEK+ cells had human CD31-expressing and VE-cadherin-expressing endothelial cells in the vessels of the ischemic muscles and/ or human endothelial cells expressing CD31, kinase-insert domain-containing receptor, and endothelial nitric oxide synthase in liver sinusoidal cells, whereas such endothelial cells were detected in only 3 of the 7 recipients engrafted with CD34+TEK- cells. This result has important implications in cell therapy using CB cells for treating hematopoietic disorders and vascular diseases.

Heterogeneous activation of the Fanconi anemia pathway by patient-derived FANCA mutants

Fanconi anemia (FA) is an autosomal recessive disorder of hematopoiesis characterized by hypersensitivity to DNA crosslinkers such as mitomycin C (MMC). There is growing evidence for a model of the FA pathway, wherein a nuclear multiprotein complex of five FA proteins (FANCA, C, E, F and G) regulates activation of FANCD2 into a monoubiquitinated form, which, collaborating with the BRCA1 machinery, affects cellular response to DNA damage. However, the role of the FA pathway in defective DNA damage response caused by various mutant forms of FA proteins has not been fully assessed. In the present study, 21 patient-derived FANCA mutants with a missense or a small in-frame deletion were expressed in FANCA-deficient fibroblasts and examined for complementation of MMC sensitivity and for reconstitution of the FA pathway: FANCA phosphorylation, interaction with FANCC, FANCF and FANCG and nuclear localization and FANCD2 monoubiquitination. The altered FANCA proteins complemented MMC sensitivity at different grades: five proteins (group I) behaved like wild-type FANCA, whereas the other proteins were either mildly (group II, n=4) or severely (group III, n=12) impaired. Group I proteins showed an apparently normal reconstitution of the FA pathway, thus they may be pathogenic by reducing endogenous expression or possibly benign polymorphisms. Reconstitution of the FA pathway by group II and III mutants closely correlated with cellular sensitivity to MMC. The different activation of the FA pathway may partly account for the phenotypic variation seen in FA patients.

Effect of wax melting range and investment liquid concentration on the accuracy of a three-quarter crown casting

STATEMENT OF PROBLEM

Dental casting accuracy is influenced by the setting expansion of investment materials. Although setting expansion can help compensate for casting shrinkage, it cannot be fully realized under a confined wax pattern. Exactly how soft a wax pattern should be to ensure optimum setting expansion has not been determined.

PURPOSE

In this study, the relationship between wax characteristics and the casting accuracy of a three-quarter crown was investigated.

MATERIAL AND METHODS

Four different wax materials were used: paraffin 135 with a softening temperature of 37.5 degrees C (P38), paraffin 1080 with a softening temperature of 63.5 degrees C, Shofu Red with a softening temperature of 41.5 degrees C, and Shofu Hard with a softening temperature of 51 degrees C. Two mixtures of phosphate-bonded investment were prepared: one with 100% special liquid and another with 75% special liquid plus 25% distilled water. For both, the liquid/powder ratio was 16:100. A type IV gold alloy was cast into a three-quarter crown mold. The discrepancy at 6 locations (1 lingual, 1 mesial, 1 distal, and 3 facial) was measured with a traveling microscope. Five readings were collected. Means and standard deviations were calculated for all data. A 2-way analysis of variance followed by the Student-Newman-Keuls test for multiple comparisons was used to identify significant differences between groups at the 95% confidence level.

RESULTS

For the gingival measurement sites (lingual, mesial, and distal), there was no significant difference in cast adaptation when Shofu Hard and paraffin 1080 waxes were used. However, the results with these 2 waxes were different than with Shofu Red and P38. For the 3 facial measurement sites, significantly different measurements were found for each wax; P38 demonstrated the best results. Casting shrinkage was smaller with the use of 100% special liquid.

CONCLUSION

Within the limitations of this study, casting shrinkage was affected by the type of wax used and was sensitive to the site at which dimensional measurements were performed. The higher the softening temperature, the larger the casting shrinkage.

A cytoplasmic serine protein kinase binds and may regulate the Fanconi anemia protein FANCA

Fanconi anemia (FA) is an autosomal recessive disease with congenital anomalies, bone marrow failure, and susceptibility to leukemia. Patient cells show chromosome instability and hypersensitivity to DNA cross-linking agents. At least 8 complementation groups (A-G) have been identified and 6 FA genes (for subtypes A, C, D2, E, F, and G) have been cloned. Increasing evidence indicates that a protein complex assembly of multiple FA proteins, including FANCA and FANCG, plays a crucial role in the FA pathway. Previously, it was reported that FANCA was phosphorylated in lymphoblasts from normal controls, whereas the phosphorylation was defective in those derived from patients with FA of multiple complementation groups. The present study examined phosphorylation of FANCA ectopically expressed in FANCA(-) cells. Several patient-derived mutations abrogated in vivo phosphorylation of FANCA in this system, suggesting that FANCA phosphorylation is associated with its function. In vitro phosphorylation studies indicated that a physiologic protein kinase for FANCA (FANCA-PK) forms a complex with the substrate. Furthermore, at least a part of FANCA-PK as well as phosphorylated FANCA were included in the FANCA/FANCG complex. Thus, FANCA-PK appears to be another component of the FA protein complex and may regulate function of FANCA. FANCA-PK was characterized as a cytoplasmic serine kinase sensitive to wortmannin. Identification of the protein kinase is expected to elucidate regulatory mechanisms that control the FA pathway.

Histopathologic analysis of angiogenic factors in localized renal cell carcinoma: the influence of neoadjuvant treatment

BACKGROUND

This study was conducted in order to clarify whether histopathologic analysis of factor thymidine phosphorylase (TP) and Factor VIII could be a useful predictor of postoperative recurrence in localized renal cell carcinoma. Therefore, the relationship between tumor infiltrated lymphocytes (TIL) and both TP and Factor VIII was studied.

METHOD

Of the 71 patients who underwent surgery, 54 patients had no neoadjuvant therapy (group 1), 10 patients were preoperatively administered IFN-gamma (group 2), and the remaining seven patients preoperatively received IFN-gamma and transarterial embolization (group 3). Both TP and Factor VIII immunostaining were performed on formalin-fixed, paraffin-embedded archival tissue from 71 renal cell carcinoma specimens, while TIL immunostaining was performed on frozen sections. Positive immunostaining was quantitatively scored by a computer-assisted digital image analysis. For TIL, positive results were semiquantitatively scored.

RESULTS

A significant difference in the recurrence-free rate was recognized for Groups 1, 2 and 3 (P < 0.05). Therefore, the median TP-positive rate (PR), VIII-PR, number of microvessels and positive mean vascular area levels were investigated, between the recurrence cases (n = 6) and the recurrence-free cases (n = 11). Only the TP-PR levels showed a significant difference among them (P = 0.044). In regards to the neoadjuvant cases, a significant correlation was observed between both VIII-PR and CD4 (r = 0.815) as well as between VIII-PR and CD11b (r = 0.756).

CONCLUSION

There was no clear evidence that the neoadjuvant treatment would increase the recurrence-free survival in patients with localized renal cell carcinoma. TP-PR might be a predictor of postoperative recurrence in patients with localized renal cell carcinoma.

Prompt and durable hematopoietic reconstitution by unrelated cord blood transplantation in a child with Fanconi anemia

We describe here the case of an 8-year-old girl with Fanconi anemia (FA) whose hematopoiesis was successfully restored by unrelated umbilical cord blood (UCB) transplantation. The patient became resistant to androgen therapy, and developed intracranial hemorrhage and dyserythropoiesis. Her hematopoietic recovery after the transplantation was excellent and a complete chimerism has been durably maintained. UCB should be considered as a stem cell source for transplantation when a patient with FA does not have an HLA-identical unaffected sibling donor.

Cytoreductive surgery with liver-involved renal cell carcinoma

The purpose of this study was to demonstrate the benefits of cytoreductive surgery for renal cell carcinomas that also involve the liver. Between 1994 and 1997, four patients with renal cell carcinoma with liver involvement were surgically treated with nephrectomy and hepatectomy. Two of them underwent a simultaneous hepatectomy and nephrectomy (group 1), and the remaining two patients underwent a hepatectomy after a nephrectomy and had a diagnosis of postoperative recurrence (group 2). Two patients, one from each group, died of multiple bone metastasis and lung metastasis 30 months and 12 months after the hepatectomy; the second patient from group 1 died 40 months after the first operation due to gastrointestinal hemorrhaging. The second patient from group 2 displayed no evidence of recurrence 18 months after the second surgical procedure. The survival rates for these patients were 66% and 33% at 1 and 3 years, respectively. Autopsy studies revealed that one patient from group 2 had a local recurrence in the liver while the other two patients from group 1 did not. Our results suggested that a progressive approach may therefore be useful for patients demonstrating renal cell carcinoma where there is liver involvement.

Improvement in bronchiolitis obliterans organizing pneumonia in a child after allogeneic bone marrow transplantation by a combination of oral prednisolone and low dose erythromycin

We report a 13-year-old boy who developed dyspnea at rest 1 year after the occurrence of cGVHD following an allogeneic bone marrow transplant (BMT). Pulmonary function data, imaging studies, lung biopsy, and bronchoalveolar lavage were consistent with the diagnosis of bronchiolitis obliterans organizing pneumonia (BOOP). Although reports suggest that oral methylprednisolone or methylprednisolone pulse therapies improve BOOP after BMT, we treated our patient with a combination of oral prednisolone (1 mg/kg) and low dose erythromycin (10 mg/kg) to avoid the side-effects of high-dose steroids. With this therapy, our patient showed clinical and radiological improvements within 1 week. The steroids were tapered off 12 months later and erythromycin was given for 14 months. We conclude that therapy consisting of a combination of oral prednisolone and low-dose erythromycin for BOOP after BMT may minimize the dose and duration of steroid use.

Massive pericardial and pleural effusion with anasarca following allogeneic bone marrow transplantation

A 10-year-old girl presented with massive pericardial/pleural effusion with anasarca 216 days after an allogeneic bone marrow transplantation from her HLA-matched sibling for relapsed acute lymphoblastic leukemia. She did not show any other symptoms of chronic graft-versus-host disease (GVHD). The antinucleolar antibody was elevated in the blood and the pleural fluid. The lymphocytes in the fluid were mostly CD8+/HLA-DR+, and a majority of CD8+ cells in the blood expressed CD57. These data suggested that she had chronic GVHD. Immunosuppressive therapy including prednisolone, cyclosporin A, high-dose methylprednisolone, tacrolimus (FK506), and methotrexate had no effect, and the patient died of Aspergillus pneumonia 183 days after the presentation of the disease. Although it has not been described before, isolated serositis with edema should be recognized as a clinical feature of chronic GVHD.

Expansion of human NOD/SCID-repopulating cells by stem cell factor, Flk2/Flt3 ligand, thrombopoietin, IL-6, and soluble IL-6 receptor

Here, we demonstrate a significant ex vivo expansion of human hematopoietic stem cells capable of repopulating in NOD/SCID mice. Using a combination of stem cell factor (SCF), Flk2/Flt3 ligand (FL), thrombopoietin (TPO), and a complex of IL-6 and soluble IL-6 receptor (IL-6/sIL-6R), we cultured cord blood CD34(+) cells for 7 days and transplanted these cells into NOD/SCID mice. Bone marrow engraftment was judged successful when recipient animals contained measurable numbers of human CD45(+) cells 10-12 weeks after transplantation. When cells were cultured with SCF+FL+TPO+IL-6/sIL-6R, 13 of 16 recipients were successfully engrafted, and CD45(+) cells represented 11.5% of bone marrow cells in engrafted recipients. Cells cultured with a subset of these factors were less efficiently engrafted, both as measured by frequency of successful transplantations and prevalence of CD45(+) cells. In animals receiving cells cultured with all 4 factors, human CD45(+) cells represented various lineages, including a large number of CD34(+) cells. The proportion of CD45(+) cells in recipient marrow was 10 times higher in animals receiving these cultured cells than in those receiving comparable numbers of fresh CD34(+) cells, and the expansion rate was estimated at 4.2-fold by a limiting dilution method. Addition of IL-3 to the cytokine combination abrogated the repopulating ability of the expanded cells. The present study may provide a novel culture method for the expansion of human transplantable hematopoietic stem cells suitable for clinical applications.

The IVS4 + 4 A to T mutation of the fanconi anemia gene FANCC is not associated with a severe phenotype in Japanese patients

Fanconi anemia (FA) is an autosomal recessive disease characterized by congenital anomalies, aplastic anemia, and a susceptibility to leukemia. There are at least 8 complementation groups (A through H). Extensive analyses of the FA group C gene FANCC in Western countries revealed that 10% to 15% of FA patients have mutations of this gene. The most common mutation is IVS4 + 4 A to T (IVS4), a splice mutation in intron 4, which has been found only in patients of Ashkenazi Jewish ancestry. When we screened 29 Japanese patients (20 unrelated patients and 4 families) using polymerase chain reaction-single strand conformation polymorphism, we found 8 unrelated patients homozygous for IVS4. This is apparently the first non-Ashkenazi-Jewish population for whom this mutation has been detected. The Ashkenazi Jewish patients homozygous for IVS4 have a severe phenotype, in comparison with other FA patients. Our analyses of Japanese patients indicate no significant difference between IVS4 homozygotes and other patients with regard to severity of a clinical phenotype. Thus, ethnic background may have a significant effect on a clinical phenotype in FA patients carrying the same mutation. (Blood. 2000;95:1493-1498)

Histopathological and immunohistochemical studies of membranes of deacetylated chitin derivatives implanted over rat calvaria

Membranes made of 65, 70, 80, 94, and 100% deacetylated chitin (chitosan) were implanted subperiosteally over the calvaria of 100 rats. Reactions were studied at 1, 2, 4, and 8 weeks after implantation. Membranes prepared with 65, 70, and 80% deacetylated chitin initially elicited marked inflammatory reactions that subsided in time with granulation tissue formation and osteogenesis. Osteocalcin-positive cells were detected immunohistochemically in the granulation tissue. On the other hand, membranes made of 94% deacetylated chitin and chitosan showed mild inflammation and minimal osteogenesis. The results indicate that membranes made of 65, 70, and 80% deacetylated chitin enhance osteogenesis at the site of their implantation. However, the initially severe inflammatory reaction associated with these materials needs to be controlled before the materials would be suitable for clinical application.

Effect of hydroxyapatite content on physical properties and connective tissue reactions to a chitosan-hydroxyapatite composite membrane

The present study investigated the effect on certain physical properties of adding various amounts of hydroxyapatite (HAP) to chitosan sol. Also investigated were connective tissue reactions to a composite membrane that is being developed for possible use in guided tissue regeneration and for the limitation of HA particle migration at sites of implantation. The physical properties evaluated were shrinkage, tensile strength, hardness, calcium ion release, and morphology. Assessment of physical properties indicated that a ratio of HA to chitosan sol of 4/11 by weight is optimal in the preparation of the composite membrane. Subperiosteal implantation of the membranes over rat calvaria revealed that the membranes were well tolerated, with fibrous encapsulation and occasional areas of osteogenesis. Increasing the hydroxyapatite content seems to enhance membrane degradation.

[Clinical trial of antithymocyte globulin for prophylaxis of acute graft-versus-host disease in pediatric recipients of bone marrow transplantation from unrelated donors]

We studied the effectiveness of antithymocyte globulin (ATG) in preventing acute graft-versus-host disease (a-GVHD) in children who received bone marrow transplants from unrelated HLA-matched donors at one institution. Of 39 patients who received transplants between 1993 and 1997, 23 were given ATG on the basis of informed consent. Either Thymoglobulin (Pasteur Merieux, 2.5 mg/kg/day) or Lymphoglobulin (15 mg/kg/day) was administered for 4 days. a-GVHD (> or = grade II) developed in 33% of the ATG group (n = 21) and in 44% of the non-ATG group (n = 16). Although a-GVHD (> or = grade II) appeared less frequent in the ATG group, the difference was not statistically significant. Among the subjects with hematological malignancies, no significant difference was observed in frequency of a-GVHD (> or = grade II) or 3-year survival rate for the ATG group (n = 10) and non-ATG group (n = 16). However, the incidence of cytomegalovirus infection was much higher (p < 0.01) in the ATG group (70%) than in the non-ATG group (19%). From this study, we were not able to confirm the benefits of ATG as described by other investigators.

In vitro properties of a chitosan-bonded bone-filling paste: studies on solubility of calcium phosphate compounds

The present study investigated properties of various mixtures of organic acids (malic and malonic) and calcium phosphate compounds (beta-tricalcium phosphate, ashed bovine bone, and synthetic hydroxyapatite) with the objective of determining the optimum combination of organic acid and calcium phosphate compound for components of a chitosan-bonded bone-filling paste. beta-tricalcium phosphate was decomposed by malic acid and malonic acid, but these two acids did not decompose synthetic hydroxyapatite and ashed bovine bone. Assessment of ion release from a set paste containing either synthetic hydroxyapatite or ashed bovine bone indicated that only calcium ions were appreciably released after storing and stirring the set paste in physiologic saline for 7 days.