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Biomedical subjects

R W Jackson

Publications and source records attributed to R W Jackson.

At least 55 records · Page 3Linked to original sources
PubMed1995

The excimer laser in orthopaedics.

This review details clinical and laboratory experience with the 308 nm XeCl excimer laser. This ultraviolet laser is not approved yet for use in arthroscopy, but has been shown to be extremely proficient for debridement of degenerate articular cartilage and meniscus. It has fewer advantages than conventional techniques for synovectomy, meniscectomy, and lateral release. Preliminary in vitro and in vivo studies were performed to investigate the character of laser-irradiated articular cartilage and to search for evidence of regeneration. A model of arthritis was created in rabbits to test the effects of the laser. Partial-thickness cuts in articular cartilage also were irradiated to test for cartilage regeneration. In vitro results indicated that the cartilage was sealed, with only a negligible loss in thickness. The results of live rabbit studies initially showed a similar sealing under scanning electron and light microscopy; however, it tended to break down in time. The results of autoradiographic and histologic studies showed no evidence of cartilage regeneration. Recent evidence suggests that the laser may adversely affect chondrocyte vitality in a region beyond the region of visible damage. There is no evidence to suggest that the laser is mutagenic.

Animals↗
PubMed1994

An in vivo study of the effect of excimer laser irradiation on degenerate rabbit articular cartilage.

Eighteen adult rabbits with mechanically induced degenerative arthritis of one knee were divided into two groups. The first group underwent arthrotomy and lavage of the arthritic joint. The second group underwent arthrotomy and irradiation of the degenerate articular surface with the Excimer (xenon chloride ultraviolet, 308-nm) laser (Arthrex Arthrolase MAX-10, Germany) in a saline environment. Rabbits from each group were killed at intervals up to 12 weeks for histological and metabolic studies of their articular cartilage. In the control group there was no improvement in the macroscopic or microscopic appearance of the articular surface. In the laser-irradiated group initially there was macroscopic and microscopic smoothing of the fibrillated surface. By 6 weeks the surface had begun to show the reappearance of fibrillation. There was no evidence that there was any increase or decrease in mitotic or metabolic activity in the laser-irradiated group as compared with the controls.

Animals↗
PubMed1993

Glial cell-specific mechanisms of TGF-beta 1 induction by IL-1 in cerebral cortex.

Transforming growth factor beta-1 (TGF-beta 1) immunoreactive product (IRP) has recently been detected in autopsied brains of individuals who died with central nervous system diseases and/or fever but not in normal individuals or in normal rodent brain. However, the mechanism(s) of induction of TGF-beta 1 in brain and the identity of cells expressing TGF-beta 1 need to be understood before a role, if any, for this potent pleiotropic cytokine in neuropathogenesis can be discerned. Towards this end we determined that IL-1 stimulated the production of TGF-beta 1 IRP in cells and TGF-beta 1 activity in culture fluids of all glial cells, astrocytes, microglial cells, and oligodendrocytes, derived from neonatal rat cortex and grown in cell type-enriched cultures. TGF-beta 1 production in vitro varied with the cell type and isoform of IL-1. Oligodendrocytes produced the most and astrocytes the least amount of TGF-beta 1. IL-1 alpha stimulated TGF-beta 1 production in all glial cell types, whereas IL-1 beta did not. In vivo, TGF-beta 1 IRP was detected in human tissues from cerebral frontal cortex and subcortical white matter only when interleukin-1 (IL-1) was elevated in the same tissues. Moreover, the amount of detectable TGF-beta 1 was positively correlated with the amount of detectable IL-1 (rho = 0.605; P = 0.003), as determined by morphometry. Double-labelling of cells for their phenotypic markers and expression of TGF-beta 1 indicated that all glial cells, but not neurons, expressed TGF-beta 1. IL-1 alpha and IL-1 beta IRPs were also detected in all three glial cell types, most frequently in astrocytes and least frequently in microglial cells. The cells containing both cytokine IRPs were also detected. These results indicate that TGF-beta 1 may be induced by IL-1 in all glial cells of the frontal cortex, by both autocrine and paracrine mechanisms.

Animals↗
PubMed1991

Lateral retinacular release for patellofemoral pain in the older patient.

Lateral release for patellofemoral pain was performed on 39 knees in 34 patients aged greater than or equal to 30 years. At a mean follow-up of 6 years, there were 56% good or excellent results. Only 20% of patients did not achieve any benefit from the procedure. Although these results may not be as good as in the younger patient, this low morbidity procedure is nevertheless useful in the management of the older patient with patellofemoral malalignment.

Adult↗
PubMed1991

Functional testing of braces for anterior cruciate ligament-deficient knees.

Previous studies into the efficacy of bracing anterior cruciate ligament (ACL)-deficient knees have lacked objective functional testing. In this study of function the authors compare the effectiveness of three custom-made and three off-the-shelf braces in stabilizing symptomatic, unilateral, chronic, non-reconstructed, ACL-deficient knees. Ten subjects randomly performed six functional tests with each of the six test braces. Knee function was evaluated both objectively and subjectively. Two customized functional braces (Generation II Polyaxial Knee Cage and Lenox Hill Derotation Brace) provided the most objective improvement during ACL-dependent activities and also the most subjective stability. Laterally hinged braces were as effective as the more commonly used double-hinged models. Based on this study, the authors recommend the use of laterally hinged customized functional braces in the nonoperative treatment of the symptomatic ACL-deficient knee.

Adolescent↗
PubMed1989

Meniscal and articular cartilage injury in sport.

The mechanisms of injury, methods of diagnosis, and management of meniscal and articular cartilage injuries of the knee are outlined. Emphasis is placed on early and accurate arthroscopic diagnosis and treatment. Partial meniscectomy or meniscal repair is the preferred treatment in the early stage. Lavage and debridement can be useful in degenerative arthritis at a later stage.

Arthroscopy↗
PubMed1988

Chondral lesions of the femoral condyles: a system of arthroscopic classification.

Based on a study of 167 chondral lesions in 140 knees, six different types of lesions confined to the articular cartilage of the femoral condyles are recognized. They are: type I, linear crack; type II, stellate fracture; type III, flap; type IV, crater; type V, fibrillated; and type VI, degrading. The weight-bearing parts of the surfaces are the site of predilection in most cases. The mechanism behind the injuries is discussed, with types I-IV probably of acute traumatic origin, and types V and VI associated with degenerative processes.

Adult↗
PubMed1988

Value and limitations of calcium channel blockade in the treatment of pulmonary hypertension associated with CREST--case reports.

Reversible vasospasm has been hypothesized to underlie the development of pulmonary hypertension in patients with CREST. Drugs that prevent arterial spasm have been used to treat pulmonary hypertension with variable results. The disparate pulmonary hemodynamic responses to calcium channel blockade reported herein suggest that CREST patients with mild pulmonary hypertension may have a component of reversible vasospasm responsive to vasodilator therapy, whereas patients with moderate to severe pulmonary hypertension may have fixed vessel lesions precluding a satisfactory response to calcium channel blockade.

Adult↗
PubMed1988

Lateral substitution for chronic isolated anterior cruciate ligament deficiency.

Thirty-five patients who had been surgically treated for major symptomatic isolated chronic anterior cruciate ligament deficiency by lateral extra-articular reconstruction alone were reviewed at an average of five years after operation. Seventy-seven per cent of patients reviewed were improved subjectively, and 83% of patients who were examined had objective evidence of only minor instability or none at follow-up. However, only a few patients had "normal" knees and many continued to have minor symptoms of instability with some restriction of activity. Most of the unsatisfactory results were in patients with significant chondral pathology at the time of reconstruction. While an extra-articular pivot-shift repair did not correct all the symptoms and signs completely, most patients were improved subjectively and objectively, and there were few complications.

Adolescent↗
PubMed1988

Demographics in demographic-economic models: a note on the basic activity-commodity framework.

The authors present a critique of an early basic formulation for the development of demographic-economic models by M. Madden and P. W. J. Batey in 1980. They assert that more attention needs to be paid to the demographic components of these models and that "distinctions between household types must be treated more adequately, and mechanisms for changes in household type must be articulated and refined." A reply by M. Madden (pp. 1,537-42) is included, as well as a response by the authors (pp. 1,543-5).

Demography↗
PubMed1987

Memories of the early days of arthroscopy: 1965-1975. The formative years.

In the decade from 1965 to 1975, arthroscopy advanced from a medical curiosity to a useful adjunct in the treatment of joint disease. The International Arthroscopy Association was established in 1974, with the prime purpose of teaching arthroscopy and disseminating information regarding the technique. Rapid advances were made in the field of instrumentation, courses were organized, and regular meetings were held as a forum for the exchange of information. Hence, in only 10 years, the technique became an established part of knee joint surgery, and the door was opened for the exploration of other joints. Dr. Masaki Watanabe deserves full credit for his contribution, which medical historians will undoubtedly establish as one of the great advances in orthopaedic surgery in the twentieth century.

Arthroscopy↗