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Biomedical subjects

T Wright

Publications and source records attributed to T Wright.

At least 19 recordsLinked to original sources
PubMed1992

Incidence and diagnostic features of macroregenerative nodules vs. small hepatocellular carcinoma in cirrhotic livers.

In Japan, the presence of a large regenerative nodule within a cirrhotic liver, referred to as a macroregenerative nodule or adenomatous hyperplasia, is thought to play a role in the pathogenesis of hepatocellular carcinoma. These lesions, however, have received little attention outside of Japan. We examined 110 sequentially explanted cirrhotic livers for the presence of such nodules. By gross examination, 19 livers (17.3%) had 40 nodules (10 livers had more than one nodule) between 0.8 and 3.5 cm in diameter. By histological examination, 28 of these were macroregenerative nodules and 12 were hepatocellular carcinomas. Three of these hepatocellular carcinomas, however, appeared to have arisen in association with a macroregenerative nodule. We found that the architectural features of thickened cell plates, formation of trabeculae and loss of reticulin were usually very helpful in differentiating benign macroregenerative nodules from hepatocellular carcinoma. The incidence of macroregenerative nodules in our series was similar to that seen in the Japanese studies, and although we feel that they may play a role in the pathogenesis of carcinoma, we do not believe their presence is necessary for the development of hepatocellular carcinoma.

Adenoma↗
PubMed1992

Metal levels in cemented total hip arthroplasty. A comparison of well-fixed and loose implants.

In a prospective study, synovial fluid metal levels from stainless steel, cobalt-chromium, and titanium-alloy cemented total hip implants were measured. There were 37 well-fixed and 44 loose hip arthroplasties. Tissue-metal levels were quantitated in the cases revised for loosening. Retrieval analysis for implant wear was performed. Synovial fluid analysis showed a fivefold increase in metal levels of loose compared with well-fixed stainless steel implants. There was a sevenfold increase in metal levels of loose compared with well-fixed cobalt-chromium implants. There was a 21-fold increase in metal levels of loose compared with well-fixed titanium-alloy (Ti-6Al-4V) implants. Tissue-metal levels from revised cobalt-chromium implants averaged 45 micrograms/g dry tissue weight compared to 4,470 micrograms/g dry tissue weight from revised titanium-alloy implants, a 100-fold increase. Implant retrieval analysis showed severe burnishing and scratching in all titanium-alloy femoral heads and extensive burnishing and scratching in the majority of the femoral stems. Well-fixed cemented implants have similar low synovial fluid metal levels. However, when loosening of implants occurs, titanium-alloy implants release disproportionate levels of metal into synovial fluid and local tissues compared to stainless steel or cobalt-chromium.

Alloys↗
PubMed1992

Cobalt-alloy metal debris in periarticular tissues from total hip revision arthroplasties. Metal contents and associated histologic findings.

To investigate the hypothesis that an association exists between the presence of metallic particulate or ionic debris released from the components of a total hip replacement and the histologic reaction in the surrounding tissues, cobalt, chromium, nickel, and molybdenum levels were measured in periarticular tissue from 22 individuals who had revision surgery. Total tissue content of the four elements (averaged per case) ranged from 2.7 to 250 micrograms of metal per gr of dried tissue (mean, 39 micrograms/gr); however, within each case, the tissue-metal content varied more widely. The highest total tissue-metal contents occurred in cases revised for infection. Fibrosis, histiocytic reaction, hemorrhage, and necrosis were the most frequent histologic findings. Polyethylene and cement particles each appeared in approximately half of all sections, while microscopic metal particles were seen only in tissues from the infected hips. Tissue-metal content did not correlate with the histologic findings, with any of the demographic variables, nor with duration of implantation. Ratios of the individual constituent elements generally reflected the cobalt-chromium alloy composition, suggesting that metal debris was present predominantly as wear particles. Only for tissues with very low metal contents did departures of these ratios indicate the presence of ionic corrosion products. The extremely low metal contents measured in many cement-bone interfacial tissues and the few metal particles found histologically suggest that metal particles may have been less important in inflammatory reaction and loosening than cement or polyethylene particles.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Operative treatment of spinal fractures with the AO internal fixator.

A multicentered prospective trial to investigate the usefulness of the AO spinal internal fixator for the treatment of thoracolumbar fractures and fracture-dislocations was undertaken. This pedicle screw-rod system was effective in stabilizing a variety of unstable fracture patterns. It was effective in decompressing the canal of retropulsed bony fragments associated with burst fractures. By the use of this implant, sagittal plane deformity was easily corrected.

Adult↗
PubMed1991

Impaired exercise capacity in adults with moderate scoliosis.

We measured lung function and exercise tolerance in 15 adults with moderate kyphoscoliosis (thoracic curvatures between 25 degrees and 70 degrees, mean +/- SD = 46.93 degrees +/- 14.02 degrees). Forced vital capacity showed a slight reduction from values predicted from age and sex matched control subjects (3.39 +/- 1.06 vs 4.06 +/- 0.82 L, p less than 0.05). However, exercise tolerance was significantly lower than previously reported in healthy adults (VO2max = 31.60 +/- 9.12 vs 37.07 +/- 4.91 ml/kg/min, p less than 0.05). Despite the reduced exercise tolerance, the ratio of maximum tidal volume to vital capacity (VTmax/VC) was similar to that observed in healthy adults. The mean dyspnea index (VEmax/MVV) was also normal at 69.4 +/- 19.0. Hypoxic and hypercapnic ventilatory responses were within predicted normal limits at 0.67 +/- 0.37 L/min-1 fall in SaO2-1 and 1.67 +/- 0.92 L/min-1 mm Hg PCO2(-1). We conclude that the impairment of exercise performance found in adults with moderate scoliosis cannot be attributed to any important ventilatory limitation, abnormality in lung volume, or impaired chemoreceptor sensitivity. We suggest that the reduced VO2max likely arises from deconditioning and lack of regular aerobic exercise.

Adult↗
PubMed1991

Graft vs. host disease after liver transplantation in humans: a report of four cases.

Four cases of patients in whom graft vs. host disease developed after liver transplantation are described. The clinical course of each patient was similar with fever, pancytopenia, diarrhea and a skin rash developing 1 or 2 mo after liver transplantation. The clinical diagnosis was made from skin or colon biopsy specimens. Liver dysfunction did not occur in the patients at the time of diagnosis. Extrahepatic donor DNA was identified in the three patients it was tested for. Three patients died from the complications of the disease primarily related to sepsis. The other patient recovered from the graft vs. host disease but died from lymphoproliferative disease.

Adult↗
PubMed1991

The arthroscopic evaluation and characteristics of severe polyethylene wear in total knee arthroplasty.

Four hundred eighty-seven porous-coated anatomic (PCA) total arthroplasties were performed by the same surgeon between January 1982 and December 1989. Forty-three patients developed an effusion, pain, or decreased range of motion after a period of pain-free function. Average time to onset of symptoms was 4.5 years. Joint fluid aspirations were sterile and revealed the presence of high-density polyethylene crystals, best seen under a polarizing microscope. Thirty-three of these patients were arthroscopically evaluated. Extensive polyethylene wear and delamination were identified. Wear was most extensive on the medial tibial plateau. Patellar polyethylene wear was also identified. Substantial femoral component abrasions were present in areas where exposure of the tibial and patellar base plates had occurred. Diffuse granulomatous synovial tissue revealed an extensive foreign-body giant-cell reaction to polyethylene particles. In all patients, temporary symptomatic relief was obtained after arthroscopy. Thirty-two patients have, subsequently, had revision surgery. Intraoperative findings and biopsies at the time of revision confirmed the arthroscopic observations. Arthroscopy allowed the accurate diagnosis of polyethylene wear, provided temporary symptomatic relief, and facilitated preoperative revision planning. Polyethylene wear in PCA total knee replacements was related to patient characteristics (larger, younger, more active patients), nonconforming femotibial articular surfaces, thin polyethylene, heat-pressed polyethylene, and nonrigid mechanical attachment of polyethylene to metal base plate. Younger, more active, larger patients with total knee arthroplasties should be observed closely for evidence of polyethylene wear.

Aged↗
PubMed1990

Type VII collagen and 19-DEJ-1 antigen. Comparison of expression in inversa and generalized variants of recessive dystrophic epidermolysis bullosa.

The expression of type VII collagen and 19-DEJ-1 antigen was examined in 73 and 71 patients, respectively, with recessive dystrophic epidermolysis bullosa (RDEB), comprising gravis, mitis, inversa, and indeterminant subsets, to better determine the specificity and sensitivity of two monoclonal antibodies directed against these dermoepidermal junction-specific epitopes. Type VII collagen (LH 7:2 epitope) was usually absent (in 90%) in patients with the gravis variant of RDEB, whereas its expression was most often diminished (in 67%) in those with the mitis form of the disease. Only 2% and 5% of patients with gravis and mitis variants, respectively, had apparent normal amounts of type VII collagen within their skin. In contrast, six (86%) of seven patients with the inversa variant had normal expression of the antigen. Only 25% of all patients with RDEB lacked the 19-DEJ-1 antigen; of these, however, most had the gravis variant, although absence or diminution was also infrequently observed in those with the mitis and inversa forms. Intermediate findings were noted in patients classified as having indeterminant forms of RDEB. Some variability in antigen expression was also noted among affected siblings. We conclude that assessment of expression of the LH 7:2 epitope of type VII collagen may be diagnostically useful, although considerable overlap does exist between individual patients with gravis and mitis forms. 19-DEJ-1 expression is a far less sensitive probe in RDEB, although such data may prove useful in the assessment of newborns lacking the characteristic features of gravis disease. In addition, based on our experience with inversa RDEB, it would appear that altered expression of type VII collagen cannot be attributed to blister formation in this latter rare subset, since this antigen is usually strongly detected along the dermoepidermal junction, even in perilesional skin sites.

Antibodies, Monoclonal↗
PubMed1990

Structure-function aspects of the glucocorticoid receptor.

The glucocorticoid receptor belongs to a family of ligand activated nuclear receptors. In addition to steroid hormone receptors, this family also includes receptors for thyroid hormone, retinoic acid and 1,25-dihydroxyvitamin D3 as well as some receptors with as yet unknown ligands, the so called orphan receptors. It is possible that the dioxin receptor is a member of this family as well although this cannot be definitely assessed until the receptor has been cloned. Interestingly, the clofibrate receptor, believed to be involved in clofibrate induction of certain isozymes of cytochrome P-450, has recently been shown to be a member of the steroid receptor supergene family and it is conceivable that other P-450 inducers might act via as yet uncharacterized receptors belonging to the same gene family. Therefore, we should learn significantly about principles of P-450 regulation by considering basic mechanisms of glucocorticoid action; the glucocorticoid receptor probably represents the most extensively studied member of the nuclear receptor family. Our laboratory has been particularly interested in structural aspects of this receptor and has used gene technology to overexpress its different domains, particularly the DNA-binding domain, the structure of which has been resolved using NMR.

Amino Acid Sequence↗
PubMed1990

Isolation and antimicrobial susceptibility of Campylobacter coli and Campylobacter jejuni from slaughter hogs.

Cultural examination of cecal contents from 109 market weight hogs slaughtered in Prince Edward Island during May-July 1988 yielded 62 isolates of Campylobacter coli and seven Campylobacter jejuni. A commercial latex agglutination test helped to confirm the identification of Campylobacter. When tested against four drugs: erythromycin, tetracycline, kanamycin and ampicillin, 11 isolates showed multiple resistance. Resistance to erythromycin was seen in 19% and 28.6% of Campylobacter coli and Campylobacter jejuni respectively. All the isolates were susceptible to nitrofurans, gentamicin and chloramphenicol.

Ampicillin Resistance↗
PubMed1989

Epidermolysis bullosa simplex superficialis. A new variant of epidermolysis bullosa characterized by subcorneal skin cleavage mimicking peeling skin syndrome.

We report a new variant of epidermolysis bullosa simplex (EBS), termed EBS superficialis, which is characterized by the development of skin cleavage just beneath the level of stratum corneum. In two of seven patients identified, a second and more focal cleft within the lower third of the epidermis was also detected. Epidermolysis bullosa simplex superficialis appears to be transmitted as an autosomal dominant trait. It differs from other autosomal dominant forms of EBS by the common findings of milia and atrophic scarring, as well as involvement of oral and/or ocular surfaces. Epidermolysis bullosa simplex superficialis is further differentiated from peeling skin syndrome by the presence of blisters and the absence of spontaneous continual exfoliation or peeling.

Adult↗
PubMed1989

Autosomal recessive epidermolysis bullosa simplex. Generalized phenotypic features suggestive of junctional or dystrophic epidermolysis bullosa, and association with neuromuscular diseases.

With few exceptions, epidermolysis bullosa (EB) simplex is an autosomal dominant disorder characterized by rather localized and recurrent nonscarring blister formation; mucous membranes and other organs are usually uninvolved. Recently, two patients were described with an autosomal recessive form of EB simplex associated with muscular dystrophy. We now describe four additional patients with autosomal recessive EB simplex, three of whom had associated muscular dystrophy or congenital myasthenia gravis. These patients had generalized cutaneous findings, including milia, atrophic scarring, nail dystrophy, and scalp alopecia, which have been classically attributed to either junctional or dystrophic EB. Each patient had significant oral cavity involvement, and in two, marked growth retardation and anemia were also present. Our findings suggest that autosomal recessive EB simplex may be characterized by rather severe cutaneous and extracutaneous disease activity, and may be associated with at least two distinct neuromuscular diseases.

Adult↗
PubMed1989

Epidermolysis bullosa simplex: identification of a kindred with autosomal recessive transmission of the Weber-Cockayne variety.

With few exceptions, epidermolysis bullosa simplex (EBS) is transmitted as an autosomal dominant trait. All cases of autosomal recessive EBS reported to date have been associated with significant extracutaneous disease (including anemia, marked growth retardation, dentition abnormalities, and/or concurrent neuromuscular disease), early infant mortality, or often, rather extensive cutaneous involvement. In some, the cutaneous morphology has even suggested junctional or dystrophic disease. We cared for a kindred in which four individuals were affected with an autosomal recessive form of EBS with cutaneous findings most often suggestive of Weber-Cockayne disease. Except for scattered oral erosions in one patient, there was no evidence of associated extracutaneous disease. These findings demonstrate the increasing complexity of even the simplex forms of inherited epidermolysis bullosa. This obviously has implications for genetic counseling.

Adolescent↗
PubMed1988

The effects of cicletanine, a new antihypertensive compound, on the flare and weal response to histamine.

This was an open experimental pilot study in five volunteers to identify any useful effect of cicletanine in the prevention or relief of the flare and weal response to histamine injection on the forearm. Areas of the flare and weal responses to three different concentrations of intradermal histamine injection were determined. Choice reaction time was measured to assess CNS performance. Heart rate, blood pressure and visual near-point were measured as indices of autonomic response. Oral cicletanine (200 mg) reduced the flare and weal response below pretreatment values for at least 8 h (p less than 0.05). There were no apparent changes in heart rate or visual near-point, nor any sedative effects. Diastolic blood pressure was significantly elevated 6 and 8 h after cicletanine (p less than 0.05) but systolic blood pressure was not affected. These results show that cicletanine is a potent non-sedative antihistamine compound.

Adult↗
PubMed1986

Corporate interests, philanthropies, and the peace movement.

Corporate and philanthropic involvement in the peace movement is growing. In considering medical peace groups as examples, we have studied the ways that corporate and philanthropic funding have shaped the course of activism. Our methods have included: review of the Foundations Grant Index from 1974-1983; analysis of corporations' and foundations' criteria for grants in the categories of peace, arms control, and disarmament; interviews with leaders of activist organizations and with foundation officials; and our own experiences in the peace movement. Corporate interests in preventing nuclear war stem from a concern for global stability in which world markets may expand, and from a hope to frame issues posed by the peace movement in a way that will not challenge basic structures of power and finance. Several general features make peace groups respectable and attractive to philanthropies; an uncritical stance toward corporate participation in the arms race; a viewpoint that the main danger of nuclear war stems from a profound, bilateral conflict between the United States and the Soviet Union; and a single-issue focus that does not deal with the many related problems reflecting the injustices of capitalism. The two major medical groups working for peace, Physicians for Social Responsibility (PSR) and International Physicians for the Prevention of Nuclear War (IPPNW), have accomplished many goals; however, their adherence to subtle criteria of respectability and their dependence on philanthropic funding have limited the scope of their activism. The struggle for peace can not succeed without fundamental changes in the corporate system that initiates, maintains, and promotes the arms race.

Financial Management↗
PubMed1985

Endoscopic neodymium-YAG laser palliation of nonresectable esophageal malignancy.

Seven men and five women with nonresectable esophageal carcinoma were treated endoscopically with the neodymium-YAG (yttrium-aluminum-garnet) infrared laser. Before laser fulguration, tumors were dilated directly with metal olive dilators. Before treatment, mean tumor length was 5 cm with luminal occlusion averaging more than 80%. After a mean of 3.3 treatment sessions spanning 18.5 days, all patients had substantial immediate palliation. Continued symptomatic relief was noted during follow-up (mean, 83 days; range, 8 to 206 days).

Adenocarcinoma↗