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Biomedical subjects

E W White

Publications and source records attributed to E W White.

14 recordsLinked to original sources
PubMed1992

Etiologic factors of recurrent abortion and subsequent reproductive performance of couples: have we made any progress in the past 10 years?

OBJECTIVES: We hypothesize that the diagnostic yield and pregnancy outcomes of patients with recurrent abortion have improved over the past 10 years. STUDY DESIGN: The study was performed in an academic medical center. Diagnoses and outcomes for group A, a published series of 100 patients investigated for recurrent abortion in the section between 1968 and 1977, was compared with those for group B, the 131 patients seen between 1987 and 1991. A standardized protocol was followed, enhanced by new techniques and autoimmune investigations in the latter group. Results were compiled retrospectively. Descriptive statistics and chi 2 analysis were used. RESULTS: No cause could be found in 37% of patients in group A compared with 24% of couples in group B (p less than 0.05). No clear difference could be shown in the subsequent outcomes of pregnancies. CONCLUSIONS: Our ability to establish a cause of recurrent abortion has improved slightly over the past 15 years. The gain is not yet reflected in successful pregnancy rates. Multicenter trials are indicated.

Abortion, Habitual↗
PubMed1979

Uniform microporous biomaterials prepared by the Relamineform technique.

The Replamineform process provides a technique for fabricating microporous ceramic, metal and polymer biomedical implant materials. A range of pore sizes can be made in the same material, thus allowing independent study of the effect of pore size and biomaterial on incorporation of implants. This new family of biomaterials shows promise for helping to determine the optimum characteristics to enhance tissue regeneration.

Aluminum Oxide↗
PubMed1977

The restoration of the articular surfaces overlying Replamineform porous biomaterials.

Replamineform porous implants (4 mm X 4 mm diameter) were placed into full-thickness cartilage and bone defects of the weight-bearing surface of the lateral femoral condyles of adult male white rabbits. These were analyzed at 1 day, 1 week, 6 weeks, 3 months, and 6 months for 1) ingrowth of tissue within the implants and 2) restoration of the articular surface overlying them. Appropriate unfilled, but similar, control defects were also studied. Mineralized bone was seen within the substance of both the TiO2 and hydroxyapatite implants at 1 week; this extremely rapid response was present in every specimen studied and was not seen with alphaAl2O3 or control animals. With the passage of time, maturation of this bone ingrowth occurred so that by 3 months, they were all incorporated into the surrounding bone. Only the hydroxyapatite implants showed consistent regenerative healing of hyaline articular cartilage from the margins of the defects with the passage of time; this occurred whenever the subchondral bone adjacent to the defect proliferated in a "creeping" fashion over the articular aspect of the implant, and the undamaged cartilage then followed it. Fibrocartilage, and not hyaline cartilage, formed the articular surface over the TiO2 and alphaAl2O3 implants and in the controls.

Aluminum↗
PubMed1976

Preliminary report: Evaluation of tissue ingrowth into experimental Replamineform vascular prostheses.

A new experimental arterial prosthesis has been developed by replacing the minimal surface microporous calcite structure of sea urchine spines. Prostheses having a 4 mm. inside diameter and a homogenous 15 to 20 mu porous network have been prepared in bioelectric polyurethane and segmented polyurethane. Ten prostheses were placed in the femoral and carotid arteries of dogs weighing 27 to 35 kilograms and were harvested at a time interval of 3 to 14 days to characterize the tissue ingrowth. Eight of the ten prostheses were widely patent at time of harvest, with tissue ingrowth evident as early as the third day and with complete fibroblastic and capillary penetration of the 1 mm. thick walls developed by the end of one week. By 2 weeks there was uniform formation of 50 to 100 mu well organized neointimal surfaces.

Animals↗
PubMed1975

Replamineform porous biomaterials for hard tissue implant applications.

By means of the newly developed Replamineform process, the unique pore microstructures found in the skeletal calcium carbonate of certain reef corals can be replicated or reproduced with high precision in a wide variety of materials suitable for hard tissue implant and prosthetic applications. The advantages of fabricating porous biomaterials with this method include closely controlled size of both the pore diameters and the diameters of the pore interconnections, and virtually complete interconnection of the uniformly spaced pores. These properties are of great importance in implant devices, because tissue ingrowth, the stimulation of new bone formation, the suppression of undesirable scar tissue, the inhibition of adverse body responses, and firm biological fixation of the implanted material all depend upon the nature of the pore-microstructure configuration. Replamineform preparation of Al2O3, TiO2, hydroxyapatite, silver, Co-Cr-Mo alloys, and polymers is described in detail, and the characterization procedures used to determine the physical and structural properties of their materials are discussed. A few of the routinely measured characteristics include (1) quantitative computerized SEM image analysis for determining the volume, size and shape distributions of the macro and microporosity and the grain size measurement of the solid; (2) nondestructive x-radiography of specimens to reveal any internal defects; (3) mechanical strength measurements of randomly selected specimens. Experimental results up to now clearly demonstrate the superiority of microstructures imparted to metals, ceramics, and polymers with the Replamineform process.

Aluminum↗
PubMed1975

Tissue ingrowth of Replamineform implants.

The Replamineform process, a new technique for the fabrication of porous hard tissue implant materials which replicates the skeletal configuration of certain marine invertebrates, was used to manufacture 1 cm long by 0.5 cm diam cylinders. The inherent advantages of porous configurations obtained through this process are controlled, uniform pore size, controlled pore-microstructure ratio, and complete interconnection of pores. The specific materials studied were chrome-cobalt-molybdenum alloy, alphaA103, hydroxyapatite prepared by hydrothermal conversion, and the basic (aragonite) CaCO3 skeleton of the coral genus Porities. The implants were placed in the canellous bone of the distal femora and proximal tibiae of adult, mongrel dogs and analyzed at 8 weeks for tissue response and ingrowth. Uniformly, new bone was found to grow into the pores of these materials and become normally mineralized. These findings were determined by microradiography, scanning electron microscopy, electron microprobe analysis, and histology. No evidences of infection, rejection, or encapsulation were seen. In the case of those CaCO3 implants left in place for 1 year, there was almost complete resorption of the cylinders, with both bony trabeculae and unmineralized collagen (presumably osteoid) found at the sites of insertion.

Aluminum↗
PubMed1972

Replamineform: a new process for preparing porous ceramic, metal, and polymer prosthetic materials.

The replamineform process (meaning replicated life forms) is a technique for duplicating the microstructure of carbonate skeletal components in ceramic, metal, or polymer materials. The special pore structures of marine invertebrate skeletal materials such as echinoid spines and corals, which are difficult or impossible to create artificially, can thus be copied in useful materials. Of immediate interest is the possibility of using these replicated microstructures in the fabrication of orthopedic prosthetic devices. By means of this technique, prosthetic materials having a controlled pore microstructure for optimum strength and tissue ingrowth may be obtained.

Animals↗