Two young men were seen with nausea, vomiting, dermatitis, seizure after two-four days of occupational exposure to caprolactam, a nylon fiber precursor. There were no significant results in laboratory test, brain CT, EEG except leukocytosis, hyperglycemia. Caprolactam has been shown to induce convulsive disorder in experimental animal studios and Tuma et al (1981) described that one worker acutely exposed to caprolactam developed generalized tonic-clonic seizure with leukocytosis. The coincidence of typical skin lesion with otherwise unexplained generalized tonic-clonic seizure in those young man strongly suggests that caprolactam was causal agent.
Animals ; Brain ; Caprolactam* ; Dermatitis ; Electroencephalography ; Humans ; Hyperglycemia ; Leukocytosis ; Male ; Nausea ; Nylons ; Occupational Exposure ; Seizures* ; Skin ; Vomiting

PURPOSE: This in vitro study intended to investigate the mechanical and thermal characteristics of Valplast, and of polymethyl methacrylate denture base resin in which different esthetic fibers (E-glass, nylon 6 or nylon 6.6) were added. MATERIALS AND METHODS: Five groups were formed: control (PMMA), PMMA-E glass, PMMA-nylon 6, PMMA-nylon 6.6 and Valplast resin. For the transverse strength test the specimens were prepared in accordance with ANSI/ADA specification No.12, and for the impact test ASTM D-256 standard were used. With the intent to evaluate the properties of transverse strength, the three-point bending (n=7) test instrument (Lloyd NK5, Lloyd Instruments Ltd, Fareham Hampshire, UK) was used at 5 mm/min. A Dynatup 9250 HV (Instron, UK) device was employed for the impact strength (n=7). All of the resin samples were tested by using thermo-mechanical analysis (Shimadzu TMA 50, Shimadzu, Japan). The data were analyzed by Kruskal-Wallis and Tukey tests for pairwise comparisons of the groups at the 0.05 level of significance. RESULTS: In all mechanical tests, the highest values were observed in Valplast group (transverse strength: 117.22 +/- 37.80 MPa, maximum deflection: 27.55 +/- 1.48 mm, impact strength: 0.76 +/- 0.03 kN). Upon examining the thermo-mechanical analysis data, it was seen that the E value of the control sample was 8.08 MPa, higher than that of the all other samples. CONCLUSION: Although Valplast denture material has good mechanical strength, its elastic modulus is not high enough to meet the standard of PMMA materials.
Caprolactam ; Denture Bases ; Dentures ; Elastic Modulus ; Glass ; Nylons ; Polymers ; Polymethyl Methacrylate

OBJECTIVETo explore the effects of the gelatin (Gt)/(polycaprolactam) PCL composite nanofiber scaffold on wound healing of full-thickness defect in rabbits.

METHODSSixteen rabbits were inflicted with full-thickness skin open wounds on the back, and they were divided into A group (with treatment of Gt/PCL nanofiber membrane, 8 wounds), B group (with treatment of PCL fiber membrane, 8 wounds), and C group (with treatment of vaseline gauze, 8 wounds), the wounds in A , B groups served as self controls. Wound healing time was recorded. Wound healing rates were calculated on 3, 7, 10 post operation day (POD). Wound specimens and their adjacent skin were examined histologically on 3, 7, and 10 POD.

RESULTSThere was obvious difference in wound healing time among A, B, C groups, and they were (18.2 +/- 1.3) d, (20.3 +/- 1.1) d, (22.0 +/- 0.6) d, respectively. Wound healing rate in A group was obviously higher than that in B, C group on 3, 7, 10 POD (P < 0.05). Compared with those in other groups, the proliferation of granulation tissue in dermis in A group was less, the epidermal cells were proliferated quickly, and collagen was arranged regularly.

CONCLUSIONGt/PCL composite nanofiber membrane can promote wound healing of full-thickness skin defect in rabbits, which is an ideal material for tissue engineering.

Animals ; Caprolactam ; chemistry ; Disease Models, Animal ; Gelatin ; chemistry ; Nanocomposites ; chemistry ; Rabbits ; Tissue Scaffolds ; Wound Healing

OBJECTIVETo evaluate the effects of the nano-hydroxyapatite/polyamide 6 (n-HA/PA6) on the proliferation and osteoblastic differentiation of rat bone marrow mesenchymal stem cells (BMSCs), and the feasibility of using both for constructing tissue engineered bone in the calvarias of rats with critical sized defects.

METHODSThe third passage of BMSCs were cultured in osteoblastic medium and seeded on the scaffolds of n-HA/PA6, the proliferation of the BMSCs was tested by MTT (3-{4,5-dimethylthiazol-2yl}-2,5-diphenyl-2H-tetrazolium-bromide) on scheduled dates, and the osteoblastic differentiation of the BMSCs were measured by alkaline phosphatase (ALP) staining. Furthermore, the scaffolds with or without BMSCs in rat calvarial defects, after 4 weeks, 8 weeks, and 16 weeks have been implanted. Histology and scanning electron microscope were used to test the bone healing in the different groups.

RESULTSThe BMSCs seeded on the n-HA/PA6 grew well, the proliferation of cells was not affected by the scaffold, and the staining of ALP was also positive. At 4 week and 8 week after implantation, the n-HA/PA6 with BMSCs showed more new bone formation on the surface of scaffolds, with a better osseointegration of implant and host bone when compared with the group of n-HA/PA6 without BMSCs. However, there was no significant difference between these two groups at 16 week.

CONCLUSIONThe porous n-HA/PA6 has no negative effects on the proliferation and osteoblastic differentiation of rat BMSCs, and using BMSCs as seed cells and n-HA/PA6 as scaffolds is a good choice for constructing tissue engineered bone due to the enhanced new bone formation and osseointegration.

Animals ; Bone Marrow Cells ; Bone and Bones ; Caprolactam ; analogs & derivatives ; Cell Differentiation ; Durapatite ; Mesenchymal Stromal Cells ; Polymers ; Rats ; Tissue Engineering ; Tissue Scaffolds

To compare the effects between gene therapy and gradual release carrier for bone morphogenetic protein-2 (BMP-2) in repairing bone defects, bone defects for 15 mm were created.on the bilateral radius in rabbits and treated with four kinds of implantations, ie, composite of transgeneic MSCs and PLA/PCL (Group A), composite of MSCs and gradual release carrier for BMP-2 (Group B), composite of MSCs and PLA/PCL (Group C), and PLA/PCL alone (Group D). After 4, 8, and 12 weeks of the operations, X-ray, histological examination, biomechanics analysis, and bone density measurement were conducted. Results showed that both osteoblasts and mesenchymal cells displayed strongly positive expression of BMP-2 in Group A after 4 weeks of the operation, the speed and quality of bone formation in Group A were much better than those in Group B. After 12 weeks of the operations, bone defects were completely repaired in Group A. BMP-2 gene therapy is really a good method to repair segmental bone defects.
Animals ; Bone Morphogenetic Protein 2 ; genetics ; therapeutic use ; Caprolactam ; analogs & derivatives ; chemistry ; Fracture Healing ; Genetic Therapy ; Implants, Experimental ; Lactic Acid ; chemistry ; Mesenchymal Stem Cell Transplantation ; methods ; Osteogenesis ; Polyesters ; Polymers ; chemistry ; Rabbits ; Radius Fractures ; therapy ; Tissue Scaffolds

Tanshinone IIA nanoparticles were constructed and perfused in rabbit's right carotid after intimal denudation with ballon. Localization and retention at different time points of the coumarin-labeled drug nanoparticles were evaluated under laser confocal microscope. Nanoparticles were seen in the three layers of the cross-section artery. At 7 days, they were mainly deposited in the medial layer, while the deposition was generally observed in the adventitia and media at 14 days and 28 days. In the Tanshinone IIA nanoparticle study, a significant reduction of the neo-intimal hyperplasia was noted by comparing the intimal area and the intima-media ratio in the three groups. And the PLGA nanoparticles appeared to be fully biocompatible. As a result, the local administration of the nanoparticles with incorporated Tanshinone IIA showed not only the preventive effects, but aslo the high absorption and good biocompatability in the whole arterial wall.
Angioplasty, Balloon ; adverse effects ; Animals ; Caprolactam ; administration & dosage ; analogs & derivatives ; Carotid Arteries ; pathology ; Diterpenes, Abietane ; Drug Carriers ; Hyperplasia ; etiology ; prevention & control ; Lactic Acid ; administration & dosage ; Nanoparticles ; Phenanthrenes ; administration & dosage ; pharmacology ; Polyesters ; Polymers ; administration & dosage ; Rabbits ; Tunica Intima ; drug effects ; pathology

Adenovirus carrying BMP-2 gene, after being mixed with fibrinous gel, was siphoned off on biodegradable scaffolds (PLA/PCL). The composite was used to repair 1.5 cm long radius defect in rabbits. Four methods were in use in the experiments: Ad-BMP-2 plus fibrinous gel and PLA/PCL (Group A), reconstructed hBMP-2 plus fibrinous gel and PLA/PCL (Group B), Ad-Lacz plus fibrinous gel and PLA/PCL (Group C), and fibrinous gel and PLA/PCL (Group D). Results showed that the defects treated in Group A were repaired with much more new bone regenerated, bridged earlier and stronger than those in Group B 12 weeks after operation. The defects treated in the other two groups could not attain osseous tissue healing. BMP-2 gene carried by biodegradable scaffold and fibrinous gel is easy to conduct and has very strong osteoinduction ability. It is really a good method to repair segmental bone defects.
Absorbable Implants ; Adenoviridae ; genetics ; metabolism ; Animals ; Biocompatible Materials ; Bone Morphogenetic Protein 2 ; biosynthesis ; genetics ; Bone Substitutes ; Caprolactam ; analogs & derivatives ; chemistry ; Fracture Healing ; Gels ; Genetic Therapy ; Humans ; Implants, Experimental ; Lactic Acid ; chemistry ; Polyesters ; Polymers ; chemistry ; Rabbits ; Radius Fractures ; therapy ; Tissue Engineering ; Tissue Scaffolds