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Biomedical subjects

K McNamara

Publications and source records attributed to K McNamara.

11 recordsLinked to original sources
PubMed1996

Stabilized polyglycolic acid fibre-based tubes for tissue engineering.

Polyglycolic acid (PGA) fibre meshes are attractive candidates to transplant cells, but they are incapable of resisting significant compressional forces. To stabilize PGA meshes, atomized solutions of poly(L-lactic acid) (PLLA) and a 50/50 copolymer of poly(D,L-lactic-co-glycolic acid) (PLGA) dissolved in chloroform were sprayed over meshes formed into hollow tubes. The PLLA and PLGA coated the PGA fibres and physically bonded adjacent fibres. The pattern and extent of bonding was controlled by the concentration of polymer in the atomized solution and the total mass of polymer sprayed on the device. The compression resistance of devices increased with the extent of bonding, and PLLA bonded tubes resisted larger compressive forces than PLGA bonded tubes. Tubes bonded with PLLA degraded more slowly than devices bonded with PLGA. Implantation of PLLA bonded tubes into rats revealed that the devices maintained their structure during fibrovascular tissue ingrowth, resulting in the formation of a tubular structure with a central lumen. The potential of these devices to engineer specific tissues was exhibited by the finding that smooth muscle cells and endothelial cells seeded onto devices in vitro formed a tubular tissue with appropriate cell distribution.

Animals↗
PubMed1995

Biodegradable sponges for hepatocyte transplantation.

Liver cell transplantation may provide a means to replace lost or deficient liver tissue, but devices capable of delivering hepatocytes to a desirable anatomic location and guiding the development of a new tissue from these cells and the host tissue are needed. We have investigated whether sponges fabricated from poly-L-lactic acid (PLA) infiltrated with polyvinyl alcohol (PVA) would meet these requirements. Highly porous sponges (porosity = 90-95%) were fabricated from PLA using a particulate leaching technique. To enable even and efficient cell seeding, the devices were infiltrated with the hydrophilic polymer polyvinyl alcohol (PVA). This reduced their contact angle with water from 79 to 23 degrees, but did not inhibit the ability of hepatocytes to adhere to the polymer. Porous sponges of PLA infiltrated with PVA readily absorbed aqueous solutions into 98% of their pore volume, and could be evenly seeded with high densities (5 x 10(7) cells/mL) of hepatocytes. Hepatocyte-seeded devices were implanted into the mesentery of laboratory rats, and 6 +/- 2 x 10(5) of the hepatocytes engrafted per sponge. Fibrovascular tissue invaded through the devices' pores, leading to a composite tissue consisting of hepatocytes, blood vessels and fibrous tissue, and the polymer sponge.

Animals↗
PubMed1994

Mortality in multiple trauma patients with fractures.

A multicentered study was performed to determine the mortality rate of patients with multiple injuries with major pelvic and long bone fractures who have early total care of their injuries. A 2-year review of patients with ISSs > or = 18 with major fractures treated at the trauma centers in Buffalo, New York, Camden, New Jersey, Nashville, Tennessee, Baltimore, Maryland, Tampa, Florida, and Seattle, Washington was performed. This group of 676 patients was compared with a similar group of 906 patients from the American College of Surgeons' Multiple Trauma Outcome Study. Mortality was significantly reduced in the patients who had early total care of all their injuries including fracture stabilization for patients less than 50 years of age and those 50 years and older. In a subgroup of patients less than 50 years of age and an ISS of 18-34 and 35-45 there was a mortality reduction from 11.8% to 5.1% and from 25.8% to 11.5%, respectively, when the fractures were managed acutely. Similar reductions in mortality were found in the patients 50 years of age and older with early fracture stabilization with a reduction from 26.4% to 8% in patients with ISSs of 18-24 and a reduction from 42.3% to 18.4% in the patients with ISSs of 35-45. This study clearly shows the additional benefit of early fracture stabilization in reducing mortality rates in the patient with multiple injuries.

Adult↗
PubMed1993

External fixation of severely comminuted and open tibial pilon fractures.

Twenty patients with severely comminuted fractures about the ankle, either severely comminuted pilon fractures or open pilon fractures (three Grade II, seven Grade III), were managed with the use of a Delta-framed external fixator across the ankle joint. All fractures had open reduction and internal fixation (ORIF) with either screw fixation or small plates to stabilize the articular surface with minimal soft-tissue dissection. Average external fixator time was 2.5 months, and the time to union averaged 4.5 months. All fractures healed. Three delayed unions required bone grafting and two had plate stabilization. No infection occurred in the 12 open fractures. There was no infection of the closed injuries, no skin sloughs, and only two minor pin tract infections. Follow-up analysis averaged 12 months (range, six to 30 months). Range of motion (ROM) at last follow-up observation was excellent in six patients, good in nine, fair in three, and poor in two. Two patients required ankle arthrodesis because of posttraumatic arthritis. The ROM and outcomes of the severely comminuted or open fractures of the distal intraarticular tibia were very good.

Adult↗
PubMed1990

Differences in family functioning among bulimics, repeat dieters, and nondieters.

This article examined bulimics' (n = 31) perceptions of how their families function relative to a group of women at risk for developing bulimia (repeat dieters) (n = 61) and a group not at risk for an eating disorder (nondieters) (n = 59). The results indicated that bulimics perceive their families to be more dysfunctional than do repeat dieters or nondieters. The bulimics reported poorer general family functioning, more affective involvement, less affective responsiveness, poorer family communication, poorer problem-solving skills, and poorer behavior control. The hypothesis that repeat dieters would evidence more family dysfunction relative to the nondieters was not supported. The results are discussed in terms of how family variables may contribute etiologically to bulimia.

Adolescent↗
PubMed1989

General practitioners' recognition and management of psychiatric illness.

All 53 of the general practitioners from one community health area of the Hunter region of New South Wales were interviewed about patients with psychiatric illnesses who had presented to their practices. Four main themes were covered: personal data which included details of medical and psychiatric training and experience; attitudes to psychiatric illness; pharmacological management; and the effectiveness of existing services. Ninety-four per cent of the general practitioners felt that dealing with psychiatric problems was an integral part of their role as a general practitioner and 60% of the general practitioners believed that their management of these problems was adequate. Patients with personality problems and those with hypochondriasis were identified as their most difficult patient groups, while inability to refer quickly was cited as the major obstacle to successful psychiatric treatment. An increased awareness of the hazards of psychotropic drugs and of the proper uses of these agents existed. Finally, private psychiatrists and the mental hospitals were criticized for not providing an adequate back-up service for this group of general practitioners.

Adult↗
PubMed1981

Treatment of xerostomia: a double-blind trial in 108 patients with Sjögren's syndrome.

The first-ever controlled study of a therapeutic modality for xerostomia is reported. A recently described formulation for saliva substitute (SS) has been tested against a glycerine mouthwash as a control saliva substitute (placebo) in a double-blind clinical trial in 108 patients with varying grades of xerostomia of Sjögren's syndrome. The results indicate that SS offered significant relief of nocturnal oral discomfort (p less than 0.02) and more patients reported "excellent" improvement (p less than 0.01) on a five-point graded response. In all other respects, the SS was not significantly better than the placebo. Significant adverse effects were not reported. It is suggested that any such current and future therapeutic modalities for Sjögren's syndrome be subjected to similar critical appraisal of their worth.

Clinical Trials as Topic↗