[The multimodality therapeutic result of stage III patients with small cell lung cancer]

BACKGROUND

To investigate the multimodality therapeutic result of stage III patients with small cell lung cancer.

METHODS

The clinical data of 89 patients with small cell lung cancer in stage III, which were treated systematically with chemotherapy or radiotherapy-operation-chemotherapy-radiotherapy from 1983 to 1993 , were analysed retrospectively and compared to those of 66 control patients with small lung cancer in stage III, which were treated with chemotherapy or/ and radiotherapy in the same period.

RESULTS

The 1- , 3- and 5-year survival rates in the multimodality therapy group were 75. 3 %(67/ 89) , 20. 2 %(18/ 89) and 9. 0 %(8/ 89) , and in the control group they were 48. 5 %(32/ 66) , 12. 1 %(8/ 66) and 0 ( P < 0. 01) . The 1- , 3- and 5-year survival rates for stage IIIA in the multimodality group were 86. 4 %(51/ 59) , 27. 1 %(16/ 59) and 13. 6 %(8/ 59) , and were 53. 3 %(16/ 30) , 6. 7 %(2/ 30) and 0 respectively ( P < 0. 01) for stage IIIB. For stage IIIA patients , the 5-year survival rates of radical resection and palliative resectoin were 18. 4 %(7/ 38) and 4. 8 %(10/ 21) respectively ( P < 0. 01) . For stage IIIB ,whether expanded or palliative resection ,no one survived over 5 years. The 1- , 3- and 5-year survival rates were 76. 3 %(29/ 38) , 18. 4 %(7/ 38) and 2. 6 %(1/ 38) for total pneumonectomy , and 80. 9 %(38/ 47) , 23. 4 %(11/47) and 12. 8 %(6/ 47) for lobectomy. Significant difference in 5-year survival rate was found between pneumonectomy and lobectomy group ( P < 0. 05) .

CONCLUSIONS

The clinical TNM stage is the decisive factor influencing the survival rate. Multimodality therapy could improve the survival rate obviously. Radical resection is proper for stage IIIA patients ,but for stage IIIB , whether expanded or palliative resection , the long-term survival isn't satisfactory. So we should strictly choose candidates for surgery.

[Inner-hemangioma ligation and pingyangmycin injection in hemangioma (with 30 cases report)]

OBJECTIVE

To provide a simple and safe surgical approach in treating cavernous and racemose hemangioma.

METHODS

First cross-ligate the hemangioma, as to divide the tumor into independent compartments, them inject pingyangmycin into the compartments respectively.

RESULTS

There are 30 cases in this group (35 hemangiomas). Twenty-four cases (28 hemangiomas) were totally cured, accounting for 80%; Six cases were improved (7 hemangiomas) for 20%; There was no ineffective case.

CONCLUSION

"Inner-hemangioma ligation and injection of pingyangmycin" has broad surgical indications, with desirable outcome in treating cavernous and racemose hemangioma, especially those unsuitable for surgery, or ineffective simply by inner-hemangioma injection.

[Genetic polymorphisms of Rb and susceptibility of esophageal cancer]

OBJECTIVE

To assess the possible association between the polymorphisms of Rb (intron 20, 17) and susceptibility of esophageal cancer so as to provide clues for genetic markers of esophageal cancer.

METHODS

Samples were taken from 56 normal Han people of Shaanxi, 47 esophageal cancer samples, and 31 peri-cancerous non-tumor. DNAs were analysed by using PCR technique.

RESULTS

Ten alleles fragments were found in Han population of Shannxi by using primer Rb gene (intron 20). PIC was 0.86. Heterozygosity was 0.7. In esophageal cancer tissues, PIC was 0.82. Heterozygosity was 0.55. In peri-cancerous non-tumor, PIC was 0.87. Heterozygosity was 0.74. Distribution of genotype frequency was significantly different between Han population of Shaanxi and esophageal cancer (P < 0.01). Two alleles (945 bp, 630 bp + 315 bp) fragments were found in Han population of Shaanxi by using primer Rb gene (intron 17). Genotype frequency of Han population of Shaanxi was A/A: 0.28, A/B: 0.52, B/B: 0.20. Genotype frequency of esophageal cancer was A/A: 0.11, A/B: 0.77, B/B: 0.12. Distribution of genotype frequency was significantly different between Han population of Shaanxi and esophageal cancer (P < 0.05). Mutation of Rb gene was found in 7 cases.

CONCLUSIONS

Polymorphism of Rb (intron 20) VNTR and Rb (intron 17) could be used as valuable markers. There should bea relationship between polymorphism of Rb VNTR and esophageal cancer susceptibility.

Superinduction of CYP1A1 gene expression. Regulation of 2,3,7, 8-tetrachlorodibenzo-p-dioxin-induced degradation of Ah receptor by cycloheximide

Cycloheximide superinduces the transcription of CYP1A1 in the presence of an agonist for the Ah receptor (AhR). To investigate the molecular target for "superinduction," we analyzed the agonist-induced degradation of AhR. Whereas 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD), a potent agonist of AhR, induces a rapid reduction of the AhR protein, cycloheximide blocks the down-regulation of steady state AhR. Analyses of the turnover of AhR reveal that cycloheximide blocks the shortening of the half-life of AhR by TCDD. Blocking of the TCDD-induced AhR degradation requires inhibition of protein synthesis, because (a) cycloheximide inhibits protein synthesis at the concentration at which it causes superinduction and inhibition of AhR degradation; and (b) puromycin, an inhibitor of protein synthesis by mimicking aminoacyl-tRNA, also blocks the TCDD-induced AhR degradation. The blocking of the TCDD-induced AhR degradation correlates with the superinduction of CYP1A1 gene expression in a time- and dose-dependent manner. Furthermore, cycloheximide is shown to increase the accumulation of the TCDD-activated AhR and the functional AhR x Arnt complex in nucleus. Collectively, our results reveal a mechanism of superinduction by cycloheximide by enhancing the stability of agonist-activated AhR. The finding that inhibition of protein synthesis blocks the TCDD-induced AhR turnover implicates a cycloheximide-sensitive, labile factor (designated as AhR degradation promoting factor, or ADPF) in controlling the removal of agonist-activated AhR in nucleus.

[The experimental study on the activity of rhBMP-2, coral and collagen composites inducing intramuscle bone]

OBJECTIVE

To investigate the ectopic bone induction activity of the composite of coral, collagen and rhBMP-2, and the degradation of the carriers of rhBMP-2.

METHODS

The composites of rhBMP-2, coral and collagen were implanted into the muscle pouches of mice. The mice were divided into the following four groups. Group H: each composite had 2 mg rhBMP-2, Group L: each composite had 0.5 mg rhBMP-2, Group J: each composite had only type I collagen, Group C: only coral was implanted in the muscle of mouse. Each group had 20 mice. Every 5 mice in each group were killed postoperatively after 1, 2, 4 and 8 weeks. The ectopic osteoinductive activity was assessed with histology and histomorphometry. The point counting method was applied to measure the formation of new bone and cartilage and the degradation of coral in the composites. The data was analyzed statistically using t test.

RESULTS

There was no obvious morbidity in any of the animals in this study, and no wound infection, bleeding, or feeding difficulties postoperatively. The samples were examined histologically. Cartilage and bone induction occurred in Group H and L. After 1 Week, new bone was observed in Group H, and cartilage formation occurred mainly in Group L. After 2 weeks, both cancellous bone and bone marrow elements were present in Group H and L. New bone formation was not uniform throughout the specimen. Part of the coral in the composites was not absorbed between 2 to 4 weeks postoperatively. At the 8th week, the coral in the composite was absorbed completely. While in Group J and C there was not any new cartilage or bone formation. According to the statistical analysis, bone formation occurred 2 weeks earlier in Group H than in Group L after operation. From 4 postoperative weeks, no difference of the bone formation rate was observed between Group H and Group L. The degradation rate of coral in Group C was the fastest among the four groups.

CONCLUSION

The composites of rhBMP-2, coral and collagen are degradable bone substitutes with bone induction and conduction, and induce dosedependent and time-dependent amounts of intramuscle bone in mice during limited postoperative period. The coral in the composites could be absorbed completely.

[Ultrasonically guided radio-frequency ablation of liver tumors with a clustered electrode: a report of 100 cases]

OBJECTIVE

To evaluate the efficacy of ultrasonically guided radio-frequency (RF) thermal ablation of liver tumors with a clustered electrode.

METHODS

Clinical records of 100 consecutive patients who underwent RF tissue ablation 120 times were analysed. Image data, tumor size, clinic manifestation, and AFP value before and after the procedure were compared.

RESULTS

A hundred cases at 10 days, thirty at 30 days, ten at 60 days after the procedure were subjected to color ultrasonography and CT scans, respectively. The tumor size decreased by 20% at 10 days in 70% patients, decreased by 30% at 30 days in 80% patients, decreased by 50% at 60 days in 3 patients. AFP value decreased in 50% of patients, no operative death was noted, and the rate of operative complication was 23% after ablation.

CONCLUSION

Ultrasound guided RF thermal ablation of hepatic tumors is safe, applicable and effective.

2,3,7,8-tetrachlorodibenzo-p-dioxin-induced degradation of aryl hydrocarbon receptor (AhR) by the ubiquitin-proteasome pathway. Role of the transcription activaton and DNA binding of AhR

Activation of the aryl hydrocarbon receptor (AhR) by 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD), a potent agonist of AhR, induces a marked reduction in steady state AhR. To analyze the mechanism of regulation of ligand-activated AhR, we examined the biochemical pathway and function of the down-regulation of the receptor by TCDD. Pulse-chase experiments reveal that TCDD shortens the half-life (t1/2) of AhR from 28 to 3 h in mouse hepatoma cells. Inhibitors of the 26 S proteasome, lactacystin and MG132, block the TCDD-induced turnover of AhR. The TCDD-induced degradation of AhR involves ubiquitination of the AhR protein, because (a) TCDD induces formation of high molecular weight, ubiquitinated AhR and (b) degradation of AhR is inhibited in ts20 cells, which bear a temperature-sensitive mutation in the ubiquitin-activating enzyme E1, at a nonpermissive temperature. Inhibition of proteasomal degradation of AhR increases the amount of the nuclear AhR.Arnt complex and "superinduces" the expression of endogenous CYP1A1 gene by TCDD, indicating that the proteasomal degradation of AhR serves as a mechanism for controlling the activity of the activated receptor. We also show that deletion of the transcription activation domain of AhR abolishes the degradation, whereas a mutation in the DNA-binding region of AhR or Arnt reduces the degradation; these data implicate the transcription activation domain and DNA binding in AhR degradation. Our findings provide new insights into the regulation of TCDD-activated AhR through ubiquitin-mediated protein degradation.

[Relationship between sex hormone levels and blood lipids/immunity in perimenopausal women]

To investigate the relationship between sex hormone levels and blood lipids/immunity and to evaluate the therapeutical effects of nylestriol, 96 women without coronary heart disease(CHD) were studied during their perimenopausal period. The estimation of serum biochemical components included serum 17 beta-estradiol(E2), testosterone(T), total cholesterol(TC), triglyceride (TC), high density lipoprotein cholesterol(HDL-C), low density protein cholesterol(LDL-C), apolipoprotein A-I(ApoAI), apolipoprotein B(ApoB), lipoprotein (a)[Lp(a)], immunoglobulin G(IgG), and IgG antibody against cardiolipin(ACAIgG). Thirty-six postmenopausal volunteers were divided into two groups and randomized to treat with either 2 mg nylestriol or placebo. In postmenopausal women, serum levels of E2, E2/T, HDL, and ApoAI decreased, while those of T, TC, TG, LDL, ApoB, Lp(a), IgG, and ACAIgG increased. Serum level of E2 was positively correlated to HDL-C and negatively correlated to TC, ApoB, LDL, IgG, and ACAIgG. Serum level of T was positively correlated to LDL, IgG, and ACAIgG and negatively correlated to HDL. In the nylestriol group, as compared with the results before treatment, serum levels of TG, TC, LDL, IgG, and ACAIgG decreased and that of HDL-C increased after treatment. We conclude that estradiol is a protective factor of CHD, whereas testerone is a dangerous factor. After menopause, the imbalance of the estradiol/testosterone ratio increases the incidence of CHD. Nylestriol is an effective substitute for estradiol to prevent CHD in post menopausal women.

Effect of stimulation of shenshu point on the aging process of genital system in aged female rats and the role of monoamine neurotransmitters

In this experiment, among some aged female rats aged over 18 months, and young female rats aged 3 months whose central noradrenergic nerve endings were injured by ventricular injection of 6-hydroxy-dopamine (6-OHDA), it was observed that catgut embedding at bilateral Shenshu (UB 23) points could obviously shorten sexual cycles, increase the frequency of sexual cycle, and slow down the aging process of the genital system in both the aged rats and in the rats with injured noradrenergic endings. After electroacupuncture (EA) at Shenshu (UB 23) points in the aged rats, the frequency of neuronal discharges in locus coeruleus (LC) was elevated and the activating rate of LC to neurons in the medial preoptic area (MPOA) of the hypothalamus was increased, while obvious effect on nucleus raphes magnus (NRM) and the effect of NRM on MPOA were not marked. It is suggested that stimulation of Shenshu (UB 23) point can strengthen the excitability of noradrenergic neurons, activate the ascending pathway of the brain stem--hypothalamus, raise the catecholamine (CA)/5-hydroxytryptamine (5-HT) ratio in the hypothalamus of the aged rats, so as to delay the aging process of the genital system.

[Experimental study on prefabricating iliac grafts using composite bone]

OBJECTIVE

To investigate the feasibility of prefabricating a specified shape autograft capable of transfer using coral and type I collagen as a carrier for recombinant human bone morphogenetic protein-2 (rhBMP-2).

METHODS

In this study, the composite of rhBMP-2, coral and type I collagen was made certain shape to prefabricate vascularized osteomuscular autograft capable of microvascular free tissue transfer and autogenous bone graft with certain shape and titanium implant in it. The composite was implanted in the iliac area in dog with the titanium implant at the same time. After 3 months and 4 and a half months of implantation, the composites were studied with gross measurement, X-ray, and histological examinations.

RESULTS

After 3 months, composited bone was turned to bone tissue, and the shape of iliac bone was changed with implant in it, bone interface was seen between new bone and implant. And new bone was matured after 4 and a half months.

CONCLUSION

Coral and type I collagen are effective carrier for rhBMP-2 to prefabricate vascular osteomuscular autograft with certain shape. The use of rhBMP-2 for tissue engineered microvascular free bone flaps has an unlimited potential and adds a new dimension to maxillofacial reconstruction.

Long-term fluoxetine produces behavioral anxiolytic effects without inhibiting neuroendocrine responses to conditioned stress in rats

The aim of the present study was to investigate the anxiolytic effects of long-term treatment with fluoxetine in rats. Selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine, are used to treat anxiety and panic disorders, in addition to treating depression. A major concern with SSRIs is a 2-3-week delay in their therapeutic effects. SSRIs share with anxiolytic 5-HT(1A) agonists the ability to produce desensitization of post-synaptic 5-HT(1A) receptors. To investigate the anxiolytic effects of fluoxetine, rats were treated for 14 days with fluoxetine (10 mg kg(-1) day(-1), i.p. ). The rats were stressed using a conditioned stress procedure and tested one day after the last fluoxetine injection. Fluoxetine decreased stress-induced defecation (by 60%), reversed the stress-induced suppression of exploring behavior (by 59%) and shortened the duration of stress-induced freezing behavior (by 11. 5%). However, the stress-induced increase in plasma levels of ACTH, corticosterone, oxytocin, prolactin and renin were not inhibited by fluoxetine treatment. These findings suggest that neuroadaptive changes induced by sustained inhibition of serotonin (5-HT) reuptake, contribute to the mechanism of the anxiolytic effects of fluoxetine. In contrast, the neuroendocrine responses to conditioned stress are not affected by these neuroadaptive changes.

Crystallization and preliminary X-ray analysis of luffaculin, a ribosome-inactivating protein from sponge-gourd seeds

Luffaculin is a ribosome-inactivating protein. Crystals suitable for X--ray diffraction were first obtained using the hanging-drop vapour-diffusion method. X-ray studies show that the crystals belong to space group C2, with unit-cell parameters a = 89.90, b = 59.82, c = 55.18 A, beta = 120.81 degrees, and have one molecule in the crystallographic asymmetric unit. The crystals diffract X-rays to at least 2.0 A resolution.

Unaltered expression of the major protease genes in a non-virulent recA-defective mutant of Porphyromonas gingivalis W83

Porphyromonas gingivalis FLL32, a recA mutant, was isolated during construction of a recA defective mutant of P. gingivalis W83 by allelic exchange mutagenesis. In contrast to W83 and FLL33, the typical recA- mutant previously reported, FLL32 was non-pigmented, lacked beta-hemolytic activity on blood agar and produced significantly less proteolytic activity. The proteolytic activity in FLL32 was mostly soluble. Expression of the rgpA, rgpB and kgp protease genes was unaltered in FLL32 when compared to FLL33 and the wild-type strain. FLL32 exhibited reduced virulence in a murine model and partially protected the animals immunized with that strain against a subsequent lethal challenge by the wild-type strain. These results indicate that the reduced level of proteolytic activity in FLL32 may be due to a defect in the processing of the proteases. Further, immunization with a non-virulent recA defective mutant of P. gingivalis can partially protect against a lethal wild-type challenge. The results from this study suggest that the recA locus may be involved in expression and regulation of proteolytic activity in P. gingivalis.

A role for neural determination genes in specifying the dorsoventral identity of telencephalic neurons

Neurogenin1 (Ngn1), Neurogenin2 (Ngn2), and Mash1 encode bHLH transcription factors with neuronal determination functions. In the telencephalon, the Ngns and Mash1 are expressed at high levels in complementary dorsal and ventral domains, respectively. We found that Ngn function is required to maintain these two separate expression domains, as Mash1 expression is up-regulated in the dorsal telencephalon of Ngn mutant embryos. We have taken advantage of the replacement of the Ngns by Mash1 in dorsal progenitors to address the role of the neural determination genes in neuronal-type specification in the telencephalon. In Ngn2 single and Ngn1; Ngn2 double mutants, a population of early born cortical neurons lose expression of dorsal-specific markers and ectopically express a subset of ventral telencephalic-specific markers. Analysis of Mash1; Ngn2 double mutant embryos and of embryos carrying a Ngn2 to Mash1 replacement mutation demonstrated that ectopic expression of Mash1 is required and sufficient to confer these ventral characteristics to cortical neurons. Our results indicate that in addition to acting as neuronal determinants, Mash1 and Ngns play a role in the specification of dorsal-ventral neuronal identity, directly linking pathways of neurogenesis and regional patterning in the forebrain.

[A study on mutation of exon 5 of presenilin-1 in Alzheimer's disease]

OBJECTIVE

To explore the role of the mutation of presenilin-1 in pathogenesis of sporadic Alzheimer's disease.

METHODS

The exon 5 of presenilin-1 was analysed by using polymerase chain reaction- single strand conformation polymorphism (PCR-SSCP) and ABI 310 genetic analyzer technique in 68 patients with Alzheimer's disease and 65 normal controls.

RESULTS

A mobility shift of SSCP in exon 5 of presenilin-1 was detected in 4 patients with Alzheimer's disease;two missense mutations were found. One mutation was at Leu 130 Met and the other at Val157 Leu. Another mobility shift of SSCP in exon 5 of presenilin-1 was detected in 11 patients with Alzheimer's disease. One missense mutation was at Leu 130 Met and one same sense mutation C462-->T. But no mobility shift of SSCP was found in patients with vascular dementia and in normal controls.

CONCLUSION

The authors found that mutations in exon 5 of presenilin-1 also existed in patients with sporadic Alzheimer's disease, which might be one of the points of mutations in sporadic Alzheimer's disease in Chinese.

Neurogenin1 and neurogenin2 control two distinct waves of neurogenesis in developing dorsal root ganglia

Different classes of sensory neurons in dorsal root ganglia (DRG) are generated in two waves: large-diameter trkC+ and trkB+ neurons are born first, followed by small-diameter trkA+ neurons. All such neurons require either neurogenin (ngn) 1 or 2, two neuronal determination genes encoding basic helix-loop-helix (bHLH) transcription factors. ngn2 is required primarily if not exclusively for the generation of trkC+ and trkB+ neurons, whereas the generation of most or all trkA+ neurons requires ngn1. Comparison with previous lineage tracing data in the chick suggests that this dichotomy reflects a requirement for the two ngns in distinct sensory precursor populations. The neurogenesis defect in ngn2(-/-) embryos is transient and later compensated by ngn1-dependent precursors, suggesting that feedback or competitive interactions between these precursors may control the proportion of different neuronal subtypes they normally produce. These data reveal remarkable parallels in the roles of bHLH factors during neurogenesis in the DRG, and myogenesis in the neighboring myotome.

The chemokine receptor CXCR4 is required for the retention of B lineage and granulocytic precursors within the bone marrow microenvironment

We report that the chemokine receptor CXCR4 is required for the retention of B lineage and granulocytic precursors within fetal liver and bone marrow microenvironment. In CXCR4-deficient embryos, pro-B cells are present in blood but hardly detectable in liver; myeloid cells are elevated in blood and reduced in liver compared to wild-type embryos. Mice reconstituted with CXCR4-deficient fetal liver cells have reduced donor-derived mature B lymphocytes in blood and lymphoid organs. The numbers of pro-B and pre-B cells are reduced in bone marrow and abnormally high in blood. Granulocytic cells are reduced in bone marrow but elevated and less mature in the blood. B lineage and granulocytic precursors are released into the periphery in absence of CXCR4.

Characterization of immortalized rabbit lacrimal gland epithelial cells

To establish an immortalized lacrimal gland epithelial cell line, the orbital lacrimal glands of normal New Zealand White rabbits were multiply injected with an immortalizing amphotropic retroviral vector (LXSN16E6E7) containing the E6 and E7 genes of human papillomavirus type 16. Lacrimal glands were removed after 2 d and acinar epithelial cells were isolated and cultured on Matrigel-coated 60 mm2 plates containing DMEM-F12 supplemented with 5% Nu-serum V. Transformed cells were selected in G418 sulfate for 7 d and passaged. Morphology of the immortalized cells was similar to that described for normal acinar cells both in vivo and in vitro, with rough endoplasmic reticulum and secretory granules. These characteristics remained unchanged and the cells continued to exhibit typical polygonal epithelioid structure. The cells have been maintained in culture for 14 mo. and have gone through 58 passages without loss of proliferation or epithelial cell characteristics. Immunohistochemistry and Western blots showed positive reactivity to secretory component, transferrin, and transferrin receptor, which are typical proteins found in the lacrimal gland. Functional analysis by stimulation with a cholinergic agonist, carbachol (100 microM), resulted in a significant release of protein. This is the first report of an immortalized rabbit lacrimal epithelial cell. These cells will provide a valuable tool for the molecular analysis of lacrimal gland epithelial cell functions.

The effects of l-arginine on crypt cell hyperproliferation in colorectal cancer

BACKGROUND

Colonic crypt cell hyperproliferation characterizes malignant and premalignant conditions of the colon and may be modified by dietary manipulation. This study compared the effect of dietary arginine supplementation on colonic crypt cell proliferation during the initiation and promotion stages of colorectal carcinogenesis.

MATERIALS AND METHODS

One hundred and twenty male Wistar rats were divided into 5 groups of 24 animals each. Groups D, DA, FA, and LA received subcutaneous injections of 1, 2-dimethylhydrazine for 20 weeks. Group D received no arginine supplement. l-arginine was given as a 1% solution instead of drinking water to Group DA for 22 weeks, to Group FA for the first 10 weeks, and to Group LA for the last 12 weeks. EDTA animals were given subcutaneous injections of EDTA for 20 weeks. Colonic crypt cell proliferation was assessed in 6 animals from each of the five groups and in 6 normal rats not given DMH or EDTA.

RESULTS

The BrdUrd-labeling index and proliferative zone were significantly decreased in all arginine groups (DA, FA, LA). The greatest reduction was evident in Group FA in which tumor incidence and tumor size were also significantly lowered.

CONCLUSIONS

When given during the initiation phase of carcinogenesis l-arginine significantly reduced colorectal tumor production and crypt cell hyperproliferation.

Theoretical far-wing line shape and absorption for high-temperature CO2

Theoretical results for the far-wing line shapes and corresponding absorption coefficients in the high-frequency wing of the nu(3) fundamental band of self-broadened CO(2) are presented for a number of temperatures between 218 and 751 K. These first-principles calculations are made assuming binary collisions within the framework of a quasi-static theory with a more accurate interaction potential than in previous calculations. The theoretical results are compared with existing laboratory data and are in good agreement for all the temperatures considered.

An experimental study on rhBMP-2 composite bone substitute for repairing craniomaxillary bone defects

OBJECTIVE

To measure bone regenerative effects in animal calvarial or mandibular critical-size defects using recombinant human bone morphogenetic protein-2 (rhBMP-2) combined with four selected carriers.

MATERIALS AND METHODS

The composite bone grafts were obtained by combining rhBMP-2 with chitin, coral, coral-based porous HA (CHA), and xenogeneic cancellous bone, respectively. These materials were implanted on the calvarial or mandibular defect of rabbits and on the calvarial defect of rats. Each carrier material was also studied as a control group. The animals were examined 2, 4, 8, and 12 weeks after implantation by radiography, histology (under light microscope and scanning electron microscope), immunohistochemistry, and biomechanics.

RESULTS

The results showed that the composite graft was absorbed gradually after it was implanted into the defect, during which time new bone was formed within the combined material in the defect site; the amount of new bone increased as time elapsed. At 12 weeks the composite was replaced completely by bone except in the CHA group. In contrast, a large amount of fibrous tissue, and little new bone, formed on the area of the bone defect when the carrier material alone was implanted.

CONCLUSIONS

All materials tested seem to be suitable carriers for rhBMP-2, which plays a very important role in new bone formation. These composite bone substitutes may be ideal materials for repairing various bone defects in the craniomaxillofacial region.

Theoretical modelling of arteriovenous malformation rupture risk: a feasibility and validation study

PURPOSE

To explore the feasibility of using a theoretical computational model to simulate the risk of spontaneous arteriovenous malformation (AVM) haemorrhage.

METHODS

Data from 12 patients were collected from a prospective databank which documented the angioarchitecture and morphological characteristics of the AVM and the feeding mean arterial pressure (FMAP) measured during initial superselective angiography prior to any treatment. Using the data, a computational model of the cerebral circulation and the AVM was constructed for each patient (patient-specific model). Two model risk (Risk(model)) calculations (haemodynamic- and structural-weighted estimates) were performed by using the patient-specific models. In our previously developed method of haemodynamic-weighted estimate, Risk(model) was calculated with the simulated intranidal pressures related to its maximal and minimal values. In the method of structural-weighted estimate developed and described in this paper, the vessel mechanical properties and probability calculation were considered in more detail than in the haemodynamic-weighted estimate. Risk(model) was then compared to experimentally determined risk which was calculated using a statistical method for determining the relative risk of having initially presented with AVM haemorrhage, termed Risk(exp).

RESULTS

The Risk(model) calculated by both haemodynamic- and structural-weighted estimates correlated with experimental risks with chi2 = 6.0 and 0.64, respectively. The risks of the structural-weighted estimate were more correlated to experimental risks.

CONCLUSIONS

Using two different approaches to the calculation of AVM haemorrhage risk, we found a general agreement with independent statistical estimates of haemorrhagic risk based on patient data. Computational approaches are feasible; future work can focus on specific pathomechanistic questions. Detailed patient-specific computational models can also be developed as an adjunct to individual patient risk assessment for risk-stratification purposes.

[Retroviral-mediated transcriptional regulatory elements of alpha-fetoprotein gene directed specific expression of interleukin-2 in murine hepatoma]

OBJECTIVE

To target expression of interleukin-2 in alpha-fetoprotein (AFP) positive hepatocellular carcinoma.

METHODS

A retroviral vector pDOR-mAFP-IL2 was constructed by coupling the transcriptional regulatory elements (TREs) of murine AFP gene with interleukin-2 cDNA in a retroviral vector.

RESULTS

Subsequent to retroviral infection, expression of IL-2 could be detected in an AFP positive murine hepatoma cell line Hepa1-6 but not in psi 2, an AFP negative murine fibroblast cell line.

CONCLUSIONS

Our results indicate that specific expression of IL-2 in hepatoma cell can be achieved by using of AFP TREs to control the expression of IL-2, and the retroviral vector which we have constructed may be used for further experimental studies on in vivo gene therapy.