bluuebunny/crossref_metadata_2025 huggingface dataset:
A bibliography of monographic works on biomaterials and biocompatibility
Authors: Bush Renee B.
Published: May 2005

Organizing and accessing biomaterials‐related information is problematic because of the interdisciplinary nature of the field. Relevant information appears in the literature of numerous science and technology subdisciplines and there is no one index or database that covers all of the related publications. An additional barrier to information retrieval is the lack of a thesaurus for the field. Multiple terms representing the same concepts are currently employed and it is not always readily apparent which terms to use in a literature search. As an aid for students and researchers in the discipline, the author provides an indexed bibliography of English language monographic works on biomaterials and biocompatibility published after 1973. © 1993 John Wiley & Sons, Inc.
Strategy for in vitro evaluation of the interactions between biomaterials and complement system
Authors: Labarre Denis , Montdargent Béatrice , Carreno Marie‐Paule , Maillet Françoise
Published: May 2005

Because of the importance of complement activation in the induced activation of leukocytes in vivo, determination of complement‐activating capacity of a candidate biomaterial is an important step in evaluating its biocompatibility. In vitro evaluation can be performed in the presence of human serum by means of techniques described in the literature and reviewed in this paper. Certain physical and chemical parameters involved in complement activation by materials have to be assessed: the chemical composition of the surface, surface area in contact with serum, temperature and duration of contact, and ionic environment with emphasis on divalent ions. Concerning materials evaluation, the adsorption of complement proteins or protein fragments has to be determined in addition to activation. Following screening tests using CH50 determination, activation of both classical and alternative pathways leading to formation of C3 convertases and formation of C5 convertase should be assessed. An example of the determination of the complement‐activating capacity of two hydroxylated materials is presented and guidelines for in vitro evaluation are proposed. © 1993 John Wiley & Sons, Inc.
Assessment of olefin‐based IUD tail strings
Authors: Roylance David
Published: May 2005

The „tail string”︁ that extends from a contraceptive intrauterine device (IUD) into the vagina is an illustrative case in materials engineering design. The strings must satisfy certain criteria for strength and other properties in order to fulfill the function of providing a means of insuring that the IUD has not been ejected, and eventually of helping remove the IUD. This must be done without contributing to an additional risk of unwanted medical side effects beyond those that may be inherent in any such device. Oriented monofilament olefins appear to satisfy these criteria, and have been used successfully in several IUD designs. This article describes a study of two such monofilaments taken from new IUDs, showing how the material's processing, structure, and properties lead to effective performance as tail strings. Several types of used IUDs were also studied, to insure that nothing occurred during use that would alter the conclusions drawn from the study of new strings. © 1993 John Wiley & Sons, Inc.
Histological response to cylinders of a low modulus titanium alloy (Ti‐13Nb‐13Zr) and a wear resistant zirconium alloy (Zr‐2.5Nb) implanted in the rabbit tibia
Authors: Goodman S. B. , Davidson J. A. , Fornasier V. L. , Mishra A. K.
Published: May 2005

To assess new and existing materials for total joint arthroplasty, the authors performed a comprehensive histomorphologic and morphometric analysis of bone to cylinders implanted transversely in the proximal tibia of mature New Zealand white rabbits. Four sterile, cylindrical implants measuring 6.1 × 3.8mm were manually inserted through drill holes in both tibiae with a „line‐to‐line fit.”︁ The materials tested included: ASTM F‐75 cast cobalt‐chrome‐molybdenum alloy, commercially pure titanium wrought zirconium‐2.5 niobium alloy, zirconium oxide coated zirconium‐2.5 niobium alloy, wrought titanium‐13 niobium‐13 zirconium alloy, and nitrogen diffusion hardened titanium‐6 aluminum‐4 vanadium alloy. Control animals with or without drill holes were included. The animals were killed by barbiturate overdose 6 months postoperatively. The upper tibiae were harvested and processed for undecalcified histologic sections that were stained with toluidine blue. The sections were examined by an investigator blind to the identity of the implanted materials. A full necropsy was also performed.

A collar of lamellar bone, of variable length and thickness, continuous with the original cortex formed a buttress around the implants. There was no evidence of foreign body or inflammatory reaction. The marrow was slightly fatty, but cells of allthree hematopoietic lines were identifiable. The materials investigated had the following ranking in decreasing order of bone contact: Ti‐13Nb‐13Zr > nitrogen hardened Ti‐6Al‐4V > C.P. titanium > Zr 2.5Nb >ZrO2 coated Zr‐2.5Nb > cast CoCr alloy. The difference between the groups was statistically significant (p = 0.05). For the variable „average bone layer thickness”︁ the ranking in decreasing order was: nitrogen hardened Ti‐6Al‐4V alloy = C.P. titanium > Ti‐13Nb‐13Zr > ZrO2/Zr‐2.5Nb > Zr‐2.5Nb > cast CoCr alloy (p = 0.19). For the variable „average bone layer thickness in bone contact regions,”︁ the ranking of the values, in decreasing order were: nitrogen hardened Ti‐6Al‐4V > C.P. titanium > ZrO2 coated Zr‐2.5Nb > Ti‐13Nb‐13Zr >Zr‐2.5 Nb > cast CoCr alloy (p = 0.02). The final necropsy reports of the animals identified no adverse findings that were concentrated to any particular implant group. The new, lower modulus materials Ti‐13Nb‐13Zr and Zr‐2.5 Nb, and nitrogen hardened Ti‐6Al‐4V appear to have a similar or superior bone response to CoCr alloy when implanted in the rabbit tibia model. © 1993 John Wiley & Sons, Inc.
Evaluation of absorbable poly(ortho esters) for use in surgical implants
Authors: Daniels A. U. , Andriano Kirk P. , Smutz W. Paul , Chang Melissa K. O. , Heller Jorge
Published: May 2005

Recent reports describe an unfavorable noninfective inflammatory response to acidic degradation products in clinical applications of bone fixation devices fabricated from bulk hydrolyzing polyglycolides and polylactides (PGA and PLA). The work described here suggests that poly(ortho esters) (POEs) offer an alternative. By comparison, hydrophobic POEs degrade predominately via surface hydrolysis, yielding first a combination of nonacidic degradation products, followed by alcoholic and acidic products gradually over time. POE specimens proved acutely nontoxic in United States Pharmacopeia tests of cellular, intracutaneous, systemic, and intramuscular implant toxicity.

Hot‐molded specimens degraded slowly in saline, retaining 92% initial stiffness (1.6 GPa flexion) and retaining 80% initial strength (66 MPa flexion) in 12 weeks. Degradation was almost unaffected by decreasing saline pH from 7.4 to 5.0. This demonstrated the relative hydrophobicity of POEs, since incorporation of small amounts of acid within the polymer markedly increases the degradation rate. Degradation rates were increased substantially by dynamic mechanical loading in saline. This may be true for other degradable polymers also, but no data could be found in the literature. Presumably, tensile loading opens microcracks, allowing water to enter.

Solvent cast POE films were strong in tension (30 + MPa tensile yield) and reasonably tough (12–15% elongation to yield). Higher molecular weight films (41–67 kDa) showed no degradation in mechanical properties after 31 days in physiological buffer at body temperature. A 27‐kDa film offered similar initial strength and stiffness but began showing mechanical degradation at 31 days. The films showed a decrease in weight with exposure time but no change in either molecular weight or water absorption at 31 days, further supporting the observation that POE degrades by surface hydrolysis rather than by bulk hydrolysis. © 1994 John Wiley & Sons, Inc.
Materials and design concepts for an intervertebral disc spacer. I. Fiber‐reinforced composite design
Authors: Langrana Noshir A. , Parsons John R. , Lee Casey K. , Vuono‐Hawkins Monica , Yang Sai Wei , Alexander Harold
Published: May 2005

The intervertebral disc is a complex joint anatomically and functionally. It may be displaced or damaged due to trauma or a disease process. To alleviate this condition, it may be necessary to remove the involved disc surgically and fuse the two adjacent vertebrae. Fusion is one option; however, replacing the damaged disc (or part thereof) with a suitable synthetic equivalent to allow near normal joint motion is more desirable. Unfortunately, the complex mechanical properties of the lumbar disc cannot be duplicated with homogeneous synthetic materials (polymers). To overcome this fundamental problem we have developed rational designs utilizing biocompatible thermoplastic elastomers of various stiffnesses (durometers) with and without fiber reinforcements. Our design consisted of three components analogous to the natural end plates, annulus, and nucleus. In this study only the fiber‐reinforced design is considered. The variables examined in the present study included orientation of the fiber layers, number of fiber layers, and order of the reinforcing layers. The results of mechanical testing of the fiber reinforced disc spacer indicate that a range of compressive and torsional properties can be achieved. The results further demonstrate that properly developed, this design results in properties similar to the natural disc. Designs developed provided adequate compression and compression torsion properties for a synthetic spine disc spacer. © 1994 John Wiley & Sons, Inc.
Stimulation of bone healing by transforming growth factor‐beta1 released from polymeric or ceramic implants
Authors: Gombotz Wayne R. , Pankey Susan C. , Bouchard Lisa S. , Phan Duke H. , Puolakkainen Pauli A.
Published: May 2005

The ability of transforming growth factor‐beta1 (TGF‐β1) to stimulate bone healing was evaluated in a rat critical calvarial defect model. Both a low dose and a high dose of TGF‐β1 were incorporated into two different types of implants: one made from a composite of poly(lactic‐co‐glycolic acid) (PLPG) (50:50) and demineralized bone matrix (DBM), and the other from calcium sulfate (CaSO4). Scanning electron microscopy showed that the CaSO4 implants were more porous than the PLPG/DBM samples. Both types of implants released biologically active TGF‐β1 for over 300 h in vitro. The samples were implanted in a 9‐mm diameter rat calvarial defect for 6 weeks along with contralateral control implants containing no TGF‐β1. Microradiography and histological analysis were used to assess the bone healing in the defects. Microradiography revealed that the greatest amount of calcified bone (67.5%) was present in the CaSO4 implants containing a high dose of TGF‐β1 while minimal new bone formation occurred in the PLPG/DBM implants. Histologically, the PLPG/DBM implants exhibited an inflammatory response with little mineralization or bone formation. The defects containing the PLPG/DBM implants consisted of a connective tissue stroma with large void spaces. Giant cells and numerous polymorphonuclear leukocytes were present throughout the implants. In contrast, the CaSO4 implants had only a few inflammatory cells and the presence of mineralization and true bone was a more consistent feature. These preliminary studies show that TGF‐β1 is capable of inducing new bone formation. Furthermore, the materials used to deliver the growth factor can play a significant role in the bone healing process. © 1994 John Wiley & Sons, Inc.
Characterization of a polyepoxy compound fixed porcine heart valve bioprosthesis
Authors: Shen Shih‐Hwa , Sung Hsing W. , Tu Roger , Hata Cary , Lin David , Noishiki Yasuharu , Quijano Rodolfo C.
Published: May 2005

Concerns with the currently available bioprostheses are calcification, long‐term durability, and suboptimal hemodynamic performance. It is well known that these concerns are all more or less related to the cross‐linking reagent, glutaraldehyde or formaldehyde, used in fixing bioprostheses. To address these concerns, we undertook the development of a porcine bioprosthesis fixed with a polyepoxy compound. In the development of this polyepoxy compound valve, it was found that the porcine leaflets fixed with polyepoxy compound were softer and more pliable than those fixed with glutaraldehyde. In this study, a special microtoming technique was developed to section the biological tissue so that the fixation uniformity in distinct layers of porcine aortic wall could be characterized. The fixation index and the denaturation temperature measurements in distinct layers of aortic walls showed that the cross‐linking density was uniform throughout the entire aortic wall for the polyepoxy compound fixed porcine valve. It was also noticed that the fixation index of the polyepoxy compound fixed aortic wall (91.5 ± 0.5, n =3) was not significantly different from that of its valvular leaflet (90.6 ± 0.8, n = 3). Similarly, the denaturation temperature of the polyepoxy compound fixed aortic wall (80.4 ± 0.9°C, n = 5) was statistically comparable to that of its valvular leaflet (79.0 ± 0.5°C, n = 5). The results of this study indicated that polyepoxy compound can adequately fix the entire porcine aortic wall as well as its valvular leaflets. In a preliminary study, three polyepoxy compound fixed valves were evaluated in the mitral position in a juvenile sheep model. At 5‐month retrieval, no calcification could be visually observed in any of the explanted valves. © 1994 John Wiley & Sons, Inc.
Fatigue behavior of a titanium femoral hip prosthesis with proximal sleeve‐stem modularity
Authors: Krygier Jan Janusz , Dujovne Ariel Ricardo , Bobyn John Dennis
Published: May 2005

Modular hip prostheses are increasing in variety and utilization. Component stability, high endurance limit, and minimal particulate debris generation are critical for long‐term clinical success. The purpose of this study was to characterize the fatigue response and evaluate the in vitro potential for component motion and wear of the S‐ROMTM, a Ti‐6Al‐4V hip prosthesis with a modular design based on a Morse taper connection. A fatigue jig was desiged to simulate fixation of the device at the sleeve‐bone interface only with distal support mainly against the lateral endosteal cortex. Two series of tests were performed in air at room temperature: one with direct vertical loading (to produce high bending moments in the coronal plane) and one with a compound loading angle directed at 15° out‐of‐plane (to include torsional physiological loads). Applied loads using a servohydraulic test machine ranged from 5 × BW (body weight) to 9 × BW (1 × BW = 73 kg, ≈ 160 lb) at 10 Hz on an Instron apparatus. No mechanical failures were observed on the 11‐mm size stems below 6 × BW for in‐plane vertical loading, and at or below 7 × BW for out‐of‐plane loading. Using displacement monitoring with a sensitivity of 35 μm, no measurable slippage or relative motion was detected between the stem and sleeve when they were properly assembled. Examination of the contact areas with scanning electron microscopy revealed random surface modification (an indication of fretting or burnishing) with occasional evidence of transfer of material between stem and sleeve. At loads under 7 × BW there was no visual evidence of loose wear debris in the presence of gross stability. Overall, the extent of surface change or wear was relatively small in all components tested at physiological load levels. © 1994 John Wiley & Sons, Inc.
Evaluation of a new absorbable lactomer® subcuticular staple
Authors: Zachmann Gregory C. , Foresman Pamela A. , Bill Timothy J. , Bentrem David J. , Rodeheaver George T. , Edlich Richard F.
Published: May 2005

The most recent advance in skin stapling is the Auto Suture® SQS®‐20 disposable stapler. It approximates and everts wound edges, placing one synthetic absorbable pin in the dermis each time the instrument handle is activated. Staple wound closure was accomplished four times faster than sutural closure of the dermis. Wounds with staple pin closure exhibit superior resistance to infection than wounds approximated by dermal sutures. Although sutures provide more immediate wound security, as measured by wound breaking strength, than dermal pins, the breaking strength of wounds subjected to either dermal pins or dermal sutures were not significantly different 14 days after wounding. © 1994 John Wiley & Sons, Inc.
Biomechanical aspects on rehydrated freeze‐dried human allograft dura mater tissues
Authors: Wolfinbarger Lloyd , Zhang Yongxing , Adam Bao‐Ling T. , Homsi Diana , Gates Kevin , Sutherland Vicki
Published: May 2005

Biomechanical properties of rehydrated freeze‐dried human dura mater tissues were studied. Scanning electron and polarized light analysis indicated a multilayered distribution of collagen fibers in the dura mater tissue. Uniaxial tensile testing of 95 test strips permitted determination of average values for failure stress (6.65 ± 0.14 MPa), failure strain (0.15 ± 0.003), tangent modulus (69.50 ± 1.29 MPa), elongation (0.56 ± 0.01), and tangent stiffness (12.53 ± 0.24 kN/m) of the dura mater tissue. © 1994 John Wiley & Sons, Inc.
A new saw technique improves preparation of bone sections for light and electron microscopy
Authors: Klein C. P. A. T. , Sauren Y. M. H. F. , Modderman W. E. , van der Waerden J. P. C. M.
Published: May 2005

A newly developed saw technique was developed to produce sections circa 10 μm or thicker from fresh bone or dentine and from plastic embedded undecalcified bone tissue with or without implant materials. The method comprises only one step because grinding or polishing to make the sections thinner is not necessary. The bone slices can be decalcified rapidly without using aggressive solvents and used for making ultrathin sections for electron microscopy. Sections of fresh dentine of 15 to 30 μm are transparent which makes it possible to study osteoclastic resorption in vitro. Sections, 10 μm thick, with an intact interface of bone and implant material can be observed for biocompatibility studies. © 1994 John Wiley & Sons, Inc.
Effects of particulate high‐density polyethylene and titanium alloy on tissue ingrowth into bone harvest chamber in rabbits
Authors: Goodman Stuart , Aspenberg Per , Song Yong , Doshi Amol , Regula Donald , Lidgren Lars
Published: May 2005

The purpose of this study was to determine whether small, phagocytosable particles of titanium alloy (Ti) and high‐density polyethylene (HDPE) have an adverse effect on bone ingrowth. The bone harvest chamber (BHC) was implanted bilaterally in the proximal tibial metaphysis of six mature rabbits. The BHC has a transverse 1‐mm wide pore providing a continuous canal through the chamber for tissue ingrowth. After an initial 6‐week period for osseointegration of the BHC, the contents of the canal were harvested repeatedly at 3 weekly intervals. This could be done with the chamber in place, without disturbing its exterior surface or the surrounding bone. The carrier solution, 1% sodium hyaluronate (Healon) was implanted first. In subsequent implantations, Healon was mixed with particles of HDPE or Ti averaging 4.7 ± 2.1 and 3.0 ± 2.6 μm, respectively. The contralateral chamber was left empty and served as a control. The chambers were harvested repeatedly, alternating experimental and control sides. The sections from the control side, and those containing Healon alone demonstrated extensive trabecular bone in a fibrovascular stroma. The sections containing Ti alloy particles were qualitatively and quantitatively similar to the control sections and those containing Healon, except for the presence of small black granules of Ti alloy, dispersed in the fibrovascular stroma or phagocytosed by scattered macrophages. The sections containing HDPE particles were infiltrated and engulfed by mononuclear and multinuclear histiocytic cells in a highly fibrous stroma. The majority of the multinucleated cells present were interpreted as being foreign body giant cells. Less trabecular bone was seen in the HDPE group compared to the other groups. Using the parameters chosen for this experiment, it would appear that small, phagocytosable HDPE particles are more deleterious to net formation of bone compared to particles of Ti alloy. © 1995 John Wiley & Sons, Inc.
Biological response to ligament wear particles
Authors: Claes Lutz E. , Ludwig Jörg , Margevicius Kristen J. , Dürselen Lutz
Published: May 2005

In ligament replacement cases where the artificial ligament has worn and partially or totally ruptured, the released wear particles have been associated with a chronic synovitis that inhibits integration of the ligament and contributes to the ultimate failure of the device. In this study, the biological response to ligament wear particles from nine different artificial ligaments was quantitatively evaluatedin vivo. Wear particles, the majority of which were <7 μm, were generatedin vitro. These particles were injected into rabbit knee joints, and the biological response as well as the systemic migration of the particles were evaluated histologically after 4 weeks. The extent of the inflammatory reaction to the ligament wear particles was found to be significantly (p< 0.05) influenced by the type of material implanted. No particles were found in the regional lymph nodes or in the spleen, liver, kidney, or lung. © 1995 John Wiley & Sons, Inc.
Bond strength of metal–ceramic systems in three‐point flexure bond test
Authors: Lenz Jürgen , Schwarz Siegmund , Schwickerath Hans , Sperner Franz , Schäfer Astrid
Published: May 2005

This study deals with a three‐point flexure test for the metal‐ceramic bond involving geometrically simple specimens (alloy strips partly coated with ceramic) that can be fabricated with reasonable expenditure and sufficient reproducibility. The calculation of the stress distribution in such specimens with the aid of the finite‐element method (FEM) is presented. The aim of this numerical analysis is: to investigate the stress distribution in a ceramometallic specimen with dimensions that, in a large number of experiments, have proven to lead to debonding at one end of the ceramic veneer instead of a crack in the middle of the veneer; and to assign a bond strength to the measured critical bending force that takes into account the influence of the Young's modulus of the alloy as well as a possible deviation of the thickness of the metal substrate from the standard value. Bond strength values of a variety of metal‐ceramic combinations are demonstrated. These experimental results demonstrate the reproducibility of the test method as well as its sensitivity to diverse parameters. The presented method is proposed as an alternative to another flexure bond test nominated for international standard. In this test ceramometallic strips are bent over a rod to a 90° angle of the specimen ends, subsequently flattened, and the fracture surface visually inspected for adherence of the ceramic to the alloy substrate along the predominant part of the middle third of the specimen. It is clear that such a test can at most deliver qualitative results. © 1995 John Wiley & Sons, Inc.
Migration of polyethylene wear debris in hip arthroplasties: A canine model
Authors: Kraemer W. J. , Maistrelli G. L. , Fornasier V. , Binnington A. , Zhao J. F.
Published: May 2005

The distal migration of polyethylene wear debris appears to be a major cause of loosening and osteolysis of cementless total hip arthroplasties. The use of modern cementing techniques, circumferential porous or hydroxyapatite (HA) coating has been advocated as a means of preventing access of the particles to the bone‐implant interface. The purpose of this study was to compare the ability of different methods of implant fixation to prevent wear debris migration. Three each of smooth, porous‐coated, HA‐coated, and cemented hemiarthroplasties were implanted in the right hip of 12 dogs. Polyethylene particles were injected into the hip once a month for 4 months and then the femurs were sectioned. The percentage bone ingrowth was 8% for the smooth, 38% for the porous, and 83% for the HA‐coated sections. Infiltration of the interface membrane by histiocytes containing polyethylene particles, and endosteal scalloping or osteolysis were found on all sections of the smooth prostheses. No particles or osteolysis were found on any sections of the other three types of prostheses. Capsular and lymph node sections from all dogs revealed histiocytic infiltration with numerous polyethylene particles present. It is concluded that the use of cement, porous, or HA coating prevents or delays access of the polyethylene wear debris to the bone‐implant interface. No one of these methods of fixation proved more advantageous in the 5‐month limit of this study. © 1995 John Wiley & Sons, Inc.
Mechanical and histological fixation of hydroxylapatite‐coated pyrolytic carbon and titanium alloy implants: A report of short‐term results
Authors: Hetherington Vincent J. , Lord Christine E. , Brown Stanley A.
Published: May 2005

Historically, pyrolytic carbon has been a material for cardiovascular applications, but it has several properties suited for orthopedic uses as well. Pyrolytic carbon has an elastic modulus similar to bone and is highly fatigue resistant, but has not been used in orthopedics because of poor fixation to bone. Plasma sprayed hydroxylapatite (HA) has significantly improved the bonding of bone to titanium alloy implants. The effect of plasma‐sprayed HA on pyrolytic carbon implants was investigated in this study. Cylindrical samples were implanted through a single cortex in Beagle femurs. The animals were sacrificed after 8 weeks, and a mechanical push‐out test was performed on the implants immediately after explantation. Samples were microradiographed, stained for histology, and examined histomorphometrically. Interface strength for each type of implant was calculated. Pyrolytic carbon showed almost no attachment strength with an average strength value of 1.59 MPa. HA‐coated pyrolytic carbon (8.71 MPa) yielded the same interfacial strength as HA‐coated titanium (8.71 MPa). Histology revealed that bone was in direct apposition to all implants, both HA coated and noncoated. Failures occurred between the core material and the coating, or within the coating, but not at the bone/HA interface. Histomorphometry results confirmed that the two types of HA‐coated implants had more bone apposition than the uncoated pyrolytic carbon implants. It was concluded that a plasma sprayed HA coating significantly improves the bone fixation of pyrolytic carbon. © 1995 John Wiley & Sons, Inc.
Immobilization of heparin oligosaccharides onto radiofrequency plasma modified pyrolytic carbon‐coated graphite
Authors: Yuan Shengmei , Cai Weizhen , Szakalas‐Gratzl Gyongyi , Kottke‐Marchant Kandice , Tweden Katherine , Marchant Roger E.
Published: May 2005

Heparin oligosaccharides with different anticoagulant activities were prepared and immobilized onto pyrolytic carbon coated graphite (PC) heart valve materials commonly used in mechanical heart valve prostheses. Prior to immobilization, PC surfaces were modified by radio‐frequency plasma polymerizedN‐vinyl‐2‐pyrrolidone (PPNVP) thin films (∼ 100 nm) and derivatized to provide surface hydroxyl groups. Cleaved, low affinity heparin (C‐heparin) with factor Xa inhibition activity of 107 to 130 IU/mg, was prepared by partial deaminative cleavage of commercial crude heparin, and high‐affinity heparin (HA‐heparin) with factor Xa inhibition activity of 550 to 1000 IU/mg was prepared by fractionation of C‐heparin using agarose‐ATIII affinity chromatography. C‐heparin and HA‐heparin were immobilized to surface modified PC by reductive amination. Anticoagulant activity of the heparin immobilized surfaces was determined by chromogenic assay for the inhibition of factor Xa. Highest surface anticoagulant activity was measured on C‐heparin immobilized surfaces (64.0 ± 7.3 mIU/cm2) compared with HA‐heparin immobilized surfaces (27.2 ± 12.2 mIU/cm2), suggesting higher binding of C‐heparin than HA‐heparin on the modified PC surfaces. Immobilized surfaces were evaluated under dynamic flow conditions, by subjecting samples to shear stress of up to 206 dyn/cm2in the presence of 5% albumin solution or human plasma. Anticoagulant activity of the immobilized heparin was retained, although reduced, and the modified surfaces showed evidence for protein resistance. © 1995 John Wiley & Sons, Inc.
Finite element analysis of crestal bone loss around porous‐coated dental implants
Authors: Vaillancourt H. , Pilliar R. M. , McCammond D.
Published: May 2005

Crestal bone loss is observed around various designs of dental implants. A possible cause of this bone loss is related to the stresses acting on periimplant bone. To investigate the relationship between stress state and bone loss, two‐dimensional finite element models corresponding to bucco‐lingual and mesio‐distal sections of canine mandibles with one of two designs of porous‐coated dental implants were analyzed. A fully porous‐coated design consisting of a solid Ti6A14V core had a porous coating over the entire outer surface of the implant component, while a partially porous‐coated design had the porous coating over the apical two‐thirds of the implant surface only. Occlusal forces with axial and transverse components were assumed to act on the implant with interface bonding and effective force transfer at all porous coat‐bone interfaces and no bonding for the non‐porous‐coated regions. The results of the analysis indicated that at most implant aspects (buccal, lingual, mesial, and distal), the equivalent stresses in crestal bone adjacent to the coronal‐most, non‐porous‐coated zone of the partially porous‐coated implants were lower than around the most coronal region of the fully porous‐coated implants. The region of lower stresses around the partially porous‐coated implants corresponded to observed areas of crestal bone loss in animal studies, suggesting that crestal bone loss in this case was due to bone disuse atrophy. A number of parameters of the finite element models were varied to determine the effect on the resulting stress fields and, therefore, possible long‐term bone remodeling. Based on differences in observed bone structures by histological examination and results of finite element analyses with fully and partially porous‐coated implants, an equivalent stress equal to 1.6 MPa was determined to be sufficient to avoid bone loss due to disuse atrophy in the canine mandibular premolar region. © 1995 John Wiley & Sons, Inc.
Self‐dual codes and the (22,8,4) balanced incomplete block design
Authors: Bilous R. T. , van Rees G. H. J.
Published: May 2005

An Erratum has been published for this article in Journal of Combinatorial Designs 14: 83–83, 2006.

We enumerate a list of 594 inequivalent binary (33,16) doubly‐even self‐orthogonal codes that have no all‐zero coordinates along with their automorphism groups. It is proven that if a (22,8,4) Balanced Incomplete Block Design were to exist then the 22 rows of its incident matrix will be contained in at least one of the 594 codes. Without using computers, we eliminate this possibility for 116 of these codes. © 2005 Wiley Periodicals, Inc. J Combin Designs.
Characteristics of a BHK cell variant defective in the cell‐substratum contact process
Authors: Shiba Yoshika , Grinnell Frederick
Published: May 2005

In this paper we document the phenotypic characteristics of a novel BHK cell adhesion variant designated FN‐2. Unlike parental cells, FN‐2 cells did not attach to fibronectin (pFN)‐coated dishes, even after 4‐hr incubations on dishes treated with 100 μg/ml of pFN. Mixing experiments with the variant and parental cells revealed that the parental cells attached normally in the presence of a ninefold excess of variant cells and the variant cells failed to attach in the presence of a ninefold excess of parental cells. Therefore, the defect in FN‐2 cells could not be explained by secretion of a factor inhibiting attachment or lack of secretion of a factor required for attachment. Also, the inability of FN‐2 cells to attach to pFN‐coated dishes could not be explained by an absence of cell pFN receptors since the variant cells bound normal numbers of small (ca. 0.8 μm) pFN‐coated latex beads, although they phagocytosed the beads poorly compared to parental cells. Also, the variant cells were not able to bind large (5.7 or 16.8 μm) pFN‐coated beads. When tested on dishes coated with ligands that, unlike fibronectin, have a high affinity for cell surface receptors, e.g., lectins and anti‐BHK antibodies, FN‐2 cells were observed to attach at a rate similar to that of parental cells but spread much more slowly. The phenotypic characteristics of FN‐2 cells suggest that they are deficient in what previously has been called the “cell contact” process in cell adhesion. It is proposed that the cell contact process is the initial formation by an individual cell of a sufficient number of cell‐substratum bonds to resist the shear forces operationally used to define “attachment,” and that more cell‐substratum bonds are necessary for cell attachment to large substrata (dishes or large beads) than for attachment to small substrata (small beads). The molecular defect in FN‐2 cells was studied by electroblotting analysis. A high molecular weight (ca. 370 kd) glycoprotein detected by blotting with anti‐BHK antibodies and ConA that was present in parental cell membranes was reduced or absent in the variant cells.
Inhibition of rat cervical epithelial cell growth by heparin and its reversal by EGF
Authors: Wright Thomas C. , Johnstone Theresa V. , Castellot John J. , Karnovsky Morris J.
Published: May 2005

The effects of heparin on the in vitro growth of rat cervical epithelial cells were examined. Heparin was found to inhbit in a dose dependent fashion the log‐phase growth of rat cervical epithelial cells (RCEC) grown in the absence of medium supplements. An inhibition of growth is observed at concentrations as low as 500 ng/ml and 50% inhibition of growth occurs at a concentration of 5 μ/ml. The growth inhibitory activity of heparin is independent of anticoagulant activity since three separate non‐anticoagulant preparations of heparin all inhibit growth. Other glycosaminoglycans including chondroitin 4‐sulfate, chondroitin 6‐sulfate, dermatan sulfate, hyaluronic acid, and keratin sulfate do not inhibit the growth of rat cervical epithelial cells. The ability of heparin to inhibit the log‐phase growth of rat cervical epithelial cells is dependent on the composition of the medium in which the cells are grown. The addition of ≥ 7.5 ng/ml epidermal growth factor to epithelial cultures blocks the growth inhibitory activity of heparin. These results suggest that components of the extracellular matrix modulate the growth responses of epithelial cells and may be important in regulating cellular proliferation in normal and pathological states.
Hormonal control of cholesterogenesis and related enzymes in isolated rat hepatocytes during pre‐ and postnatal development
Authors: Leoni S. , Spagnuolo S. , Devirgiliis L. Conti , Dini L. , Mangiantini M. T. , Trentalance A.
Published: May 2005

The effect of glucagon and insulin on the incorporation of 1‐14C‐acetate into cholesterol and fatty acids and on the enzymes involved in the first steps of cholesterol synthesis (3‐hydroxy‐3‐methyl‐glutaryl‐coenzyme A reductase, 3‐hydroxy‐3‐methyl‐glutaryl‐coenzyme A synthase, and acetoacetyl‐coenzyme A thiolase) was investigated. Isolated rat hepatocytes at different stages of fetal and postnatal development were employed. Data obtained show the appearance of hormonal control on the 18th day of fetal life, indicating the same pattern, as regards acetate incorporation and HMGCoA reductase prepared and assayed in the presence of NaF. On the contrary, HMGCoA reductase, prepared without NaF, HMGCoA synthase, and acetoacetyl CoA thiolase, does not appear to respond to hormonal stimulation. In the perinatal period, the hormonal effect is no longer detectable, probably because of a hormone resistance of this metabolic pathway.
Cell cycle traverse and protein metabolism in human NHIK 3025 cells: The role of anchorage
Authors: Rogne Sissel , Rønning Øystein W. , Myklebost Ola , Seglen Per O. , Pettersen Erik O.
Published: May 2005

We have studied the effect of cell anchorage on the human cell line NHIK 3025 in vitro, to see whether the growth regulating effect of cell anchorage primarily affected DNA division cycle or mass growth cycle. It was found that cell to cell anchorage had the same effect on cell cycle progression as anchorage to a solid surface, which indicates that it is anchorage per se and not cell shape that is important for growth control in NHIK 3025 cells. When NHIK 3025 cells were grown without attachment to a solid surface, both G1 and cell cycle duration was prolonged by 6 h, which means that the prolonged cell cycle was due to a prolonged G1. During the first part of the cell cycle the rate of protein synthesis and degradation was constant, and at the same level in cells grown with and without attachment. This means that the prolonged G1 was not due to a reduced protein accumulation or mass growth. Towards the end of the cell cycle protein accumulation was reduced. This effect was either due to a size control before cell division or a secondary effect of the prolonged G1. We therefore conclude that cell anchorage as a growth regulator primarily affects the DNA/cell division cycle.
Effects of EGF and thrombin on inositol‐containing phospholipids of cultured fibroblasts: Stimulation of phosphatidylinositol synthesis by thrombin but not EGF
Authors: Raben Daniel M. , Cunningham Dennis D.
Published: May 2005

The effects of growth factors on inositol‐containing phospholipids were investigated to test the hypothesis that alterations in their metabolism are involved in mitogenic stimulation. Thrombin and EGF stimulated comparable increases in the synthesis (30–50%) and degradation (20–40%) of phosphatidylinositol 4‐monophosphate (DPI) and phosphatidylinositol 4,5‐bisphosphate (TPI) in a cell line which is mitogenically responsive to both growth factors. The increases in synthesis were time and dose dependent in a manner which was consistent with their involvement in mitogenesis; the increases were observed only under conditions where a mitogenic response occurred. While it has been suggested that an increased synthesis of phosphatidylinositol (PI) is coupled to the stimulation of DPI and TPI synthesis, we found that thrombin stimulated an early synthesis PI but EGF did not. To further evaluate the involvement of PI in thrombin‐stimulated cell division we determined the time and dose dependence of the stimulated PI synthesis and found that it also occurred in a manner which was consistent with its involvement in thrombin‐stimulated cell division. Furthermore, the stimulated PI synthesis was not observed with nonmitogenic proteases or in cell lines which were not responsive to thrombin. These results demonstrate that the metabolism of DPI and TPI appears closely related to the mitogenic response generated by EGF and thrombin. However, an early stimulation of PI synthesis is not coupled to this metabolism and is not necessary for mitogenic stimulation by EGF. Thus, a stimulation of PI synthesis is not a valid measure of alterations in inositol‐containing phospholipids and what has been termed the “PI response.”
Separation of alkadiene‐1‐ol isomers by gas‐liquid chromatography
Authors: Schäfer W.
Published: May 2005

Complete gas‐liquid chromatographic separation of the four 10, 12‐hexadecadiene‐l‐ol isomers using a FFAPcoated glass capillary column is described.

These measurements are of importance for the analysis of pheromones from biological sources and for the control of material from stereospecific syntheses.
Operational variables of size exclusion columns with semirigid and rigid packings
Authors: Mukherji Anil K.
Published: May 2005

Systematic studies on operation variables affecting GPC separations using the semirigid Microstyragel (Waters Associates) and the rigid silica packings (DuPont) of about equivalent porosity are reported. The dependence of (a) flow rate, (b) injection volume, and (c) concentration on elution volume and theoretical plates are examined.
Deactivation of glass capillary columns by silylation. Part 1: Principles and basic technique
Authors: Grob K. , Grob G. , Grob K.
Published: May 2005

A deactivation procedure is described based on a published method using hexamethyldisilazane in the gas phase. In addition to unusually high inertia and thermostability, the method produces truly neutral columns which allow simultaneous analysis of moderately strong free acids and bases. The silylated columns show their full potential only with on‐column injection. Preliminary experimental directions are given; more elaborate directions will become available after extended optimization work.
Increased thermostability of non‐polar wall‐coated open tubular columns
Authors: Houtermans W. J. M. , Boodt C. P.
Published: May 2005

A method of deactivating the inner surface of glass capillary columns is described, which can be used at 350°C without detoriation. A non‐polar liquid phase was prepared from a commercially available liquid phase which, when coated on a glass surface, can withstand temperatures of 325°C for isothermal analysis and 350°C for temperature‐programmed analysis.

After deactivation, the column was coated using the static coating method. Then it was conditioned, tested and kept for 48 hours at 35O°C before being used for the analysis of a mixture of chlorinated pesticides.
Head space gas chromatography with glass capillaries using an automatic electropneumatic dosing system
Authors: Kolb B. , Pospisil P. , Borath T. , Auer M.
Published: May 2005

Head space GC using a special electropneumatic sampling system works well in combination with glass capillaries. Because a homogenous gas mixture is already present most problems inherent with inlet splitters are thus avoided. In cases where the high vapor pressure of the sample can cause problems with the pressure controlled sampling system, the use of narrow bore glass capillaries provides the necessary inlet pressure. The use of this powerful and convenient analytical tool for water pollution analysis, flavour analysis and the analysis of volatiles in crude oil samples is shown by examples.
The preparation of glass SCOT columns by the organic glue method
Authors: Zu‐Fong Lue , Yuen‐Yu Tung , Rhan‐Mei Chao , Qing‐Yu Ou , Pei‐Yi Yang , Kun‐Nian Dong , Wei‐Lu Yu
Published: May 2005

A technique for adhesion of fine particles (ca. 5 μ) of the 405 white diatomaceous support on the inner wall of glass tube with organic glue [poly (diethylaminoethyl methacrylate) acetate] is described. The coated tube was drawn to capillary column by using a machine designed according to Desty's. The capillary column was then coated with stationary phase (such as squaiane, QF‐1, Dexsil 300, PEG 20 M, OV‐1, SE 30 and etc.) by the conventional dynamic or static method. This preparation method has proved easy to duplicate and is simple. The coating efficiency (UTE %) is within 60–90. The theoretical plate number per meter of an SE 30 column is about 4000, and per meter of a PEG 20 M column is about 2500. The columns thus prepared have been successfully used to analyze petroleum hydrocarbons, essential oils, petrochemicals, pheromone, steroid metabolites and others.
Sample capacity in open tubular and micro‐packed columns for GC
Authors: Pretorius V. , Smuts T. W.
Published: May 2005

Equations have been derived from which the maximum sample size which may be loaded on a column without significantly affecting the performance may be calculated. It is shown that micro‐packed columns can handle a sample which is as much as forty times larger than that which can be loaded onto wall‐coated open tubular columns with comparable conditions.
Thin‐layer adsorption chromatography with mixed mobile phases. 2. Effects of solute‐solvent interactions and energetic heterogeneity of surfaces with regard to admolecules in TLC
Authors: Rózyło J. K. , Jaroniec M. , Jaroniec J. A. , Kolodziejczyk H.
Published: May 2005

In the Part 1 of this series a new equation for determining the Rm values in TLC with mixed mobile phases was proposed and examined by using the parameter m, which is a measure of energetic heterogeneity of the adsorbent surface with regard to the adsorbing molecules (admolecules).

The numerical values of m, evaluated for 13 chromatographic systems, have been compared with that of the Ościk's parameter A, which characterizes solute‐solvent interactions.
High resolution gas chromatography/mass spectrometric characterization of urinary metabolites of N,N‐diethyl‐m‐toluamide (DEET) in man
Authors: Wu Anthony , Lynn Pearson M. , Shekoski David L. , Soto Ricardo J. , Stewart Richard D.
Published: May 2005

Studies of the pharmacology and toxicology of the popular insect repellant, N,N‐diethyl‐m‐toluamide (DEET), have largely been done in animal models using radioactive tracing without the structural elucidation of its metabolites.

This paper describes a high resolution gas chromatography/mass spectrometry (GC/MS) technique and reports the results of the preliminary characterization of the metabolites of DEET in the urine of a 30‐year‐old man who had been exposed to DEET contained in a commercial product. The metabolites were extracted and separated with an OV‐101 glass capillary column, 30 m × 0.3 mm, and mass spectrometric elucidations were carried out with both Electron Impact (EI) and Chemical Ionization‐Methane (MCI) modes.

Oxidation of the benzylic moiety and hydroxylation of the sidechain of DEET molecules appeared to be the predominate routes of metabolism in man. The artifacts were also proposed.
Isomers of uroporphyrin free acids separated by HPLC
Authors: Wayne A. W. , Straight R. C. , Wales E. E. , Englert E.
Published: May 2005

A synthetic mixture of uroporphyrin isomers I, II, III and IV as free acids in the synthetic ratio of 1:1:4:2 was resolved by reverse‐phase HPLC using a C0:PEL (ODS) 37‐50 micron precolumn and a Micro Bondapak C18 analytical column eluted with acetonitrile (4%) in phosphate buffer (pH 6.95). Clinically important I and III isomers of uroporphyrin were readily resolved directly from acidified urine as porphyrin free acids.
Preparative high‐performance liquid chromatography with reversed phase packed glass columns
Authors: Eisenbeiß F. , Henke H.
Published: May 2005

An efficient system for preparative reversed‐phase separations with packed glass columns is described. The advantage of this system is the use of relatively simple and inexpensive equipment.

Column performance, load capacity, effect of the feed volume and the feed concentration on peak broadening are shown. The influence of the selectivity and the capacity factors on column load have been measured.

The effect of the column dimensions is demonstrated by means of practical applications. The loading capacity of a column depends on the thermodynamic proporties of the separation system used. It is therefore not expedient in preparative chromatography to correlate the loading capacity of a column by means of grams dissolved per grams of adsorbent.
Adsorption of [14C] phenytoin in a gas chromatographic system
Authors: Driessen O. , Emonds A.
Published: May 2005

The labelled drug [14C] phenytoin was injected into an all‐glass chromatographic system to determine adsorption on various system parts. It appeared that 10 to 20% of the amount injected did not elute. Severity of adsorption as measured from lasting radioactivity was not anticipated from peak shape or calibration curves.
Advancing the chromatography of GC/FT‐IR to WCOT capillary columns
Authors: Shafer K. H. , Bjørseth A. , Tabor J. , Jakobsen R. J.
Published: May 2005

By the use of a wide‐bore WCOT capillary column, it was possible to obtain the first on‐the‐fly GC/FT‐IR spectra with a WCOT column. This wide‐bore WCOT column gave improved separation, as compared to a SCOT column, and yielded identifiable infrared spectra for a real sample.