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Biomedical subjects

J A Massey

Publications and source records attributed to J A Massey.

15 recordsLinked to original sources
PubMed2001

Supramolecular organometallic polymer chemistry: multiple morphologies and superstructures from the solution self-assembly of polyferrocene-block-polysiloxane-block-polyferrocene triblock copolymers.

The solution self-assembly of an organometallic-inorganic triblock copolymer, poly(ferrocenyldimethylsilane)-block-poly(dimethylsiloxane)-block-poly-(ferrocenyldimethylsilane) (PFDMS-b-PDMS-b-PFDMS, 3b; block ratio 1:13:1; Mn = 2.88 x 10(4) gmol(-1), polydispersity (PDI) 1.43 (gel permeation chromatography, GPC)) was studied in n-hexane, a PDMS block selective solvent. Transmission electron microscopy (TEM), atomic force microscopy (AFM), and TEM with negative staining analysis of these micellar solutions after solvent evaporation revealed the presence of multiple micellar morphologies including spheres, cylinders, and novel flower-like supramolecular aggregates. TEM analysis of samples fractionated by ultracentrifugation and preparative size-exclusion chromatography suggest that the formation of multiple morphologies is a consequence of compositional variations. When micellar solutions were prepared at 50 degrees C (above the glass transition of the PFDMS core-forming block) flower-like micellar aggregates similar to those present in micellar solutions prepared at room temperature also formed. However, after solvent evaporation, TEM analysis of micellar solutions prepared in decane at about 150 degrees C, above the melt temperature of the PFDMS core (ca. 120-145 degrees C), revealed the presence of spherical micelles (when decane solutions at 150 degrees C were rapidly cooled to room temperature) and rod-like cylindrical micelles (when decane solutions at 150 degrees C were slowly cooled to room temperature). In contrast, poly(ferrocenylmethylethylsilane)block-poly(dimethylsiloxane)-block-poly(ferrocenylmethylethylsilane) (PFMES-b-PDMS-b-PFMES, 4; block ratio 1:16:1; Mn=2.90x10(4)g mol(-1), PDI= 1.42 (GPC)) and poly(ferrocenylmethylphenylsilane)-block-poly(dimethylsiloxane)-block-poly(ferrocenylmethylphenylsilane) (PFMPS-b-PDMS-b-PFMPS, 5; block ratio 1:15:1; Mn=3.00 x 10(4) gmol(-1), PDI = 1.38 (GPC)), which possess completely amorphous organometallic core-forming blocks, formed only spherical micelles in hexane at room temperature. These observations indicate that crystallinity of the insoluble polyferrocenylsilane block is a critical factor in the formation of the nonspherical micelle morphologies.

Journal Article↗
PubMed1995

Team management of atrophic edentulism with autogenous inlay, veneer, and split grafts and endosseous implants: case reports.

Predictable success of autogenous graft and implant reconstructions is critically dependent on preoperative alignment and prosthetic considerations planned by the surgeon and the restorative dentist in a team approach. In such cases the surgeon has an opportunity to place accurate bone grafts that allow implants to be secured in both the correct position and correct axis for good prosthetic restoration. With careful thought, the restorative dentist and surgeon can plan the location, shape, and volume of an implant-graft reconstruction. Nine requirements for successful onlay grating with implants and five case reports illustrating the team approach are presented.

Accidents, Traffic↗
PubMed1989

Urethral closure in management of urinary incontinence.

Urethral closure with suprapubic catheterization has been used in 50 patients with urethral destruction due to an indwelling catheter. Thirty-seven of the patients were dry after the initial operation. Long-term complications were seen in 33 patients. Those that did occur were not life threatening. This relatively minor procedure offers a good alternative to formal diversion in this group of severely disabled patients.

Adult↗
PubMed1988

Obstructed voiding in the female.

Bladder outlet obstruction in women is rare. The characteristics and aetiology of the condition in 163 females are discussed and their relation to treatment evaluated.

Adolescent↗
PubMed1987

Mechanisms of continence during raised intra-abdominal pressure.

Patients undergoing Stamey endoscopic bladder neck suspension were investigated urodynamically to ascertain the contribution of passive and active components in the maintenance of continence. Transmission of pressure to the proximal urethra was improved by the procedure even under muscular paralysis. This suggests that passive effects due to intra-abdominal replacement of the urethra are most significant.

Abdomen↗
PubMed1986

Dose titration in clinical trials. An example using emepronium carrageenate in detrusor instability.

Seventy-two women with proven detrusor instability completed a novel clinical trial of the new anticholinergic emepronium carrageenate (Cetiprin novum), which allowed for dose titration. The tolerated dose has been shown to correlate with the severity of symptoms. Statistically significant improvement was achieved in symptomatic and urodynamic parameters without serious side effects.

Adult↗
PubMed1986

Diagnostic testing for peripheral vascular disease.

Regardless of the type of test that a client undergoes for diagnosis of PVD, the following information should be provided: purpose of the test; level of participation required of the client during the test; length of the procedure; special preparation needed before the test; restrictions imposed after the test and for how long; and the potential risks and benefits of the test. This information should be given to the client and his significant others in oral as well as written form. Clients who undergo diagnostic testing are often anxious and do not remember verbal instructions. In conclusion, the nurse must use her clinical judgment as to the amount of technical information the client needs and desires.

Angiography↗