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Biomedical subjects

D Greenwald

Publications and source records attributed to D Greenwald.

At least 19 recordsLinked to original sources
PubMed1998

An algorithm for early aggressive treatment of frostbite with limb salvage directed by triple-phase scanning.

Frostbite injuries have traditionally been treated with expectant observation. With the exception of early blister aspiration tissues are allowed to demarcate before definitive debridement is accomplished. Triple-phase bone scanning has been used to define the extent of fatally damaged tissues in an attempt to allow for early debridement and wound closure. We suggest extending this technology to assess injury and direct debridement in patients for whom early aggressive salvage attempts are indicated. We present two cases in which triple-phase scanning was used to direct early debridement for aggressive limb salvage with flap reconstruction. Bone, ligament, tendon, and nerve were preserved and covered with vascularized tissue before the onset of frank necrosis. Postoperative scans reveal revascularization of these tissues. An algorithm incorporating triple-phase scanning for the evaluation and treatment of frostbite is presented.

Adult↗
PubMed1997

Free tissue transfer to extend the limits of limb salvage for lower extremity tissue loss.

BACKGROUND: The extent of tissue loss amenable to primary healing after revascularization is unknown. Salvage of limbs with large soft-tissue defects with exposed tendon, joint, or bone lies beyond the limits of conventional techniques. We report our results using free tissue transfer as an adjunct to lower extremity vascular reconstruction in patients with complex ischemic or infected wounds. METHODS: Retrospective chart review of patient and wound characteristics. RESULTS: From January 1992 to June 1996, 585 procedures were performed in 544 patients, including 27 free flaps in 26 patients: 17 free flaps combined with distal bypass (7 staged, 10 simultaneous) and 10 isolated free flaps. Flap donor sites included radial forearm (8), latissimus dorsi (7), rectus abdominus (9), and scapula (3). Surgical indications included extensive ischemic/neurotrophic ulcers, and nonhealing vein graft harvest incision or transmetatarsal amputation site. Mean area of tissue loss was 70 cm2, mean ulcer duration was 5 months, and 92% of patients had exposed tendon, joint, or bone. During a mean follow-up of 14 months, 2 patients died of cardiopulmonary disease and 3 flaps failed, resulting in below-knee amputation. Six flaps were revised for graft stenosis (1), venous thrombosis (1), or flap edge necrosis (4). Limb salvage rate was 70% at 24 months by life-table analysis. Functional ambulation was achieved in 21 of 24 (88%) patients, including 7 of 8 with diabetes, end-stage renal disease, and heel ulcers. CONCLUSION: In select ambulatory patients with large soft-tissue defects and exposed deep structures, functional limb salvage is obtainable in more than 80% of patients. For lesions not amenable to vascular reconstruction with conventional methods of wound coverage, free tissue transfer extends the limits of limb salvage and is a viable alternative to amputation.

Adult↗
PubMed1997

Three-year trials of personal therapy among schizophrenic patients living with or independent of family, I: Description of study and effects on relapse rates.

OBJECTIVE: The study of individual psychotherapeutic approaches to the treatment of schizophrenia has yielded equivocal findings, partly because of methodologic problems. Further, the ability of psychosocial treatments to prevent psychotic relapse appears to lessen over time. The authors' goal was to develop and test a demonstrably effective individual therapy for schizophrenia. METHOD: Using a study design that addressed previous methodologic issues, the authors evaluated personal therapy specifically designed to forestall late relapse in patients with schizophrenia. They evaluated the effectiveness of personal therapy over a period of 3 years after hospital discharge among 151 patients with schizophrenia or schizoaffective disorder diagnosed according to Research Diagnostic Criteria. The patients were randomly assigned to receive either personal therapy or contrasting therapies in one of two concurrent trials. One trial studied patients who were living with family (N = 97); the other studied patients who were living independent of family (N = 54). RESULTS: All of the patients had extensive psychiatric histories, but only 44 (29%) experienced recurrent psychotic episodes over the 3-year study period, and only 27 (18%) prematurely terminated the study; most of those who left the study were in the no-personal-therapy conditions. Among patients living with family, personal therapy was more effective than family and supportive therapies in preventing psychotic and affective relapse as well as noncompliance. However, among patients living independent of family, those who received personal therapy had significantly more psychotic decompensations than did those who received supportive therapy. CONCLUSIONS: Personal therapy had a positive effect on adverse outcomes among patients who lived with family. However, personal therapy increased the rate of psychotic relapse for patients living independent of family. The application of personal therapy might best be delayed until patients have achieved symptom and residential stability.

Adolescent↗
PubMed1997

Three-year trials of personal therapy among schizophrenic patients living with or independent of family, II: Effects on adjustment of patients.

OBJECTIVE: Previous analyses of the personal and social adjustment of outpatients with schizophrenia have either relied on the assessment of unrepresentative patients who survived without relapse or used analyses that included relapse assessments, a potential confound when different rates of relapse existed among treatment conditions. The authors' goal was to conduct a study of the effects of personal therapy on outcome that was designed to take into consideration the effects of relapse. METHOD: They evaluated the effectiveness of personal therapy over 3 years after hospital discharge among 151 patients with schizophrenia or schizoaffective disorder. The patients were randomly assigned to receive personal therapy or contrasting therapies in one of two concurrent trials. One trial included patients who were living with family (N = 97); the other included patients who were living independent of family (N = 54). Patients were assessed at 6-month intervals over 3 years of treatment on measures of personal and social adjustment; patients who relapsed and restabilized and those who did not relapse were included. RESULTS: Personal therapy had positive effects on broad components of social adjustment (role performance) but had few differential effects on symptoms, and patients receiving personal therapy remained more anxious than patients who received family or supportive therapy. For patients who were living with family, personal therapy led to better outcomes in overall performance than did the other treatments. Although family therapy had only one positive effect on patients' social adjustment, the personal adjustment (residual symptoms) of patients who received family therapy appeared to improve more than that of patients receiving personal or supportive therapy. For patients not living with family, personal therapy was more successful than supportive therapy in improving work performance and relationships out of the home. Longitudinal effects of personal therapy on symptoms were similar to those of family and supportive therapies, particularly in the first 2 years, but personal therapy effect sizes increased over time on measures of social adjustment. CONCLUSIONS: Personal therapy has pervasive effects on the social adjustment of patients with schizophrenia that are independent of relapse prevention. Supportive therapy, with or without family intervention, produces adjustment effects that peak at 12 months after discharge and plateau thereafter. However, personal therapy, a definitive psychosocial intervention, continues to improve the social adjustment of patients in the second and third years after discharge. Brief treatment would appear to be less effective than a long-term, disorder-relevant intervention for schizophrenia.

Adaptation, Psychological↗
PubMed1997

Estrogens may reduce mortality and ischemic damage caused by middle cerebral artery occlusion in the female rat.

The present study was undertaken to determine if estrogens protect female rats from the neurodegenerative effects of middle cerebral artery (MCA) occlusion. The rats were ovariectomized and 7 or 8 days later various estrogen preparations were administered before or after MCA occlusion. Pretreatment with 17beta-estradiol (17beta-E2) or a brain-targeted 17beta-E2 chemical delivery system (CDS) decreased mortality from 65% in ovariectomized rats to 22% in 17beta-E2-treated and 16% in 17beta-E2 CDS-treated rats. This marked reduction in mortality was accompanied by a reduction in the ischemic area of the brain from 25.6+/-5.7% in the ovariectomized rats to 9.8+/-4% and 9.1+/-4.2% in the 17beta-E2-implanted and the 17beta-E2 CDS-treated rats, respectively. Similarly, pretreatment with the presumed inactive estrogen, 17alpha-estradiol, reduced mortality from 36 to 0% and reduced the ischemic area by 55 to 81%. When administered 40 or 90 minutes after MCA occlusion, 17beta-E2 CDS reduced the area of ischemia by 45 to 90% or 31%, respectively. In summary, the present study provides the first evidence that estrogens exert neuroprotective effects in an animal model of ischemia and suggests that estrogens may be a useful therapy to protect neurons against the neurodegenerative effects of stroke.

Animals↗
PubMed1996

Efficiency of the flexor tendon pulley system in human cadaver hands.

The efficiency of the flexor tendon system was examined in a human cadaver model. Pulleys were randomly sectioned, and the results were evaluated on the basis of the tendon excursion, force generated at the fingertip, and the work (force multiplied by distance) involved, as compared to the intact pulley system. When a single minor pulley (A1 or A5) was cut, there was no statistical difference in work efficiency or excursion efficiency from controls. Cutting all minor pulleys (A1, A3, A5) lead to a significant loss in excursion efficiency. The intact three pulley systems of A2, A3, and A4 were near normal and statistically better than A2 and A4 together for work efficiency. Cutting one of the major pulleys (A2, A4) resulted in significant changes in efficiency, but what was unexpected was to find an 85% loss of both work and excursion efficiency for the loss of A4 but only an excursion difference of 94% for the loss of A2. Our findings demonstrated that in this model, with the influence of the skin removed, A4 absence produced the largest biomechanically measured efficiency changes and that a combination of A2, A3, and A4 was necessary to preserve both work and excursion efficiency.

Biomechanical Phenomena↗
PubMed1996

Testicular extramedullary myeloid cell tumor in a patient with myelodysplastic syndrome.

We report herein a case of extramedullary myeloid tumor arising bilaterally in the testes of a 66-year-old man, who had previously been diagnosed with myelodysplastic syndrome. Light microscopy of the testicular neoplasm demonstrated a tumor composed of large, slightly polygonal cells with pale blue to weakly eosinophilic cytoplasm. The tumor cells were immunoreactive for CD45, myeloperoxidase, lysozyme, CD43, and MB2. Many of the cells also expressed chloroacetate esterase. Peripheral blood and bone marrow findings were consistent with chronic myelomonocytic leukemia (FAB-CMML), particularly in the most recent material, which showed clear cellular dysplasia and an increase in the percentage of blasts in the bone marrow (15% to 20% of all nucleated cells). This case of extramedullary myeloid tumor is unusual in view of the patient's age and the testicular location. It emphasizes the importance of including extramedullary myeloid tumor in the differential diagnosis of histologically undifferentiated large-cell tumors, as well as a need to use a broad panel of immunohistochemical stains in such cases.

Aged↗
PubMed1995

Personal therapy: a disorder-relevant psychotherapy for schizophrenia.

While the long-term care of ambulatory schizophrenia patients requires highly effective interpersonal treatment skills among clinicians, there is little evidence to support an empirically validated individual psychotherapy of schizophrenia. Personal therapy (PT) attempts to address the apparent limitations of traditional psychotherapy by modifying the "model of the person" to accommodate an underlying pathophysiology, minimizing potential iatrogenic effects of maintenance antipsychotic medication, controlling sources of environmental provocation, and extending therapy to a time when crisis management has lessened and stabilization is better ensured. By means of graduated, internal coping strategies, PT attempts to provide a growing awareness of personal vulnerability, including the "internal cues" of affect dysregulation. The goals are to increase foresight through the accurate appraisal of emotional states, their appropriate expression, and assessment of the reciprocal response of others. The strategies are supplemented by phase-specific psychoeducation and behavior therapy techniques. Practical issues in the application of this new intervention are discussed. Preliminary observations from two samples of patients, one living with and the other living independent of family, suggest differential improvement over time among PT recipients.

Activities of Daily Living↗
PubMed1994

Mechanical comparison of 10 suture materials before and after in vivo incubation.

The material properties of ten 2-O suture materials were evaluated tensiometrically at time = 0 and again after 6 weeks incubation in rats. All suture material was incubated and tested without knots. Specialized machinery was used with a custom securing apparatus to pull suture material apart at constant speed. Stress-strain curves were derived, and from these strength, toughness, strain at rupture, and elastic modulus were determined. Sutures tested included Vicryl [poly(glycolide-lactide)], Dexon (polyglycolic acid), Ethibond (polyester), silk, plain gut, chromic gut, Maxon (polyglyconate), PDS (polydioxanone), nylon, and Prolene (polypropylene). Elastic modulus was greatest for braided, least for monofilament, and intermediate for gut sutures, regardless of chemical composition (ANOVA, P = 0.0001). Strength, strain, and toughness decreased in all of the sutures over time in vivo with the exception of braided polyester (Ethibond), which remained stable. Silk demonstrated the least strength and toughness while PDS and Maxon were the strongest and toughest at time = 0. Vicryl, Dexon, and gut sutures were absorbed to the point that they could not be tested after 6 weeks in vivo. Performance tables are provided for all sutures.

Animals↗
PubMed1994

Dynamic analysis of profundus tendon function.

A method for analysis of hand function is reported through evaluation and characterization of flexor digitorum profundus (FDP) tendon mechanics. A testing platform is used that allows for the dynamic evaluation of intact cadaver hand mechanics under normal and pathologic conditions using simultaneous measurements of tendon load, tendon excursion, grip strength, pinch strength, and joint angle. This study of FDP tendons in normal fresh cadaver hands demonstrates that FDP tendon excursion increases as the number and size of joints flexed increases. Extensor counterweighting 500 g, increases FDP tendon load and work but not excursion requirements, and FDP loads of up to 75 N are required for single finger grip strengths of 4 kg force. These loads do not result in permanent (plastic) deformation of either the tendon or the restraining soft tissues. Detailed descriptions of the platform and the mechanical tests performed are provided.

Adult↗
PubMed1994

Mesh reinforcement increases bursting strength of intestinal anastomoses in steroid-treated rabbits.

We tested the hypothesis that reinforcement of small bowel anastomoses with polyglycolic acid mesh (PGAM) would increase bursting strength in steroid-treated subjects. Twenty-two New Zealand white rabbits weighing 3-4 kg received methylprednisolone 0.2 mg/kg/day IM for 7-13 days preoperatively and until killed 4-5 days postoperatively. Steroid effect was confirmed by a 58.3 per cent decrease in absolute lymphocyte count and a histologic reduction in anastomotic fibroblast proliferation and collagen deposition. Two small bowel anastomoses were performed in each animal using standard two-layer suture technique. One of the two anastomoses, randomly assigned, was circumferentially reinforced with PGAM such that each animal served as its own control. Anastomotic bursting pressures, determined on postoperative Day 4-5, were significantly higher in mesh-reinforced anastomoses (P = 0.003). Histologic examination of the reinforced anastomoses revealed a well-developed layer of fibroblasts and collagen between the PGAM and bowel wall serosa. These results demonstrate that polyglycolic acid mesh reinforcement significantly increases the bursting strength of small bowel anastomoses in steroid-treated rabbits.

Anastomosis, Surgical↗
PubMed1991

Biomechanical analysis of intrinsic tendon healing in vitro and the effects of vitamins A and E.

This in vitro study was designed to test the hypothesis that flexor tendons have an intrinsic capability to heal as judged by rigorously defined biomechanical criteria. Rabbit forepaw flexor tendons (n = 114) were transected and repaired in zone II and cultured in standard media or media supplemented with vitamin A or E. Tenorrhaphies were disrupted at 0, 2, 8, and 12 weeks after repair by fixed-speed tensiometry. The following parameters were calculated: true stress, true strain, and normalized energy absorption. Statistical analysis was by Student's t test. Peak stress (strength) increased equally in all groups over time (p less than 0.05), while normalized energy absorption (toughness) was markedly higher in the vitamin E-treated group after 2 weeks' incubation (p less than 0.05). These data represent the first biomechanical evidence of intrinsic tendon healing in vitro. Biomechanical methodology and vitamin effects are discussed in detail.

Animals↗
PubMed1978

Nitrosamine formation in bladder infections and its role in the etiology of bladder cancer.

Dimethylnitrosamine, a powerful carcinogen, is produced in the urine of patients with urinary tract infections of Proteus mirabilis and Escherichia coli when nitrite is present. Treatment with tetracycline antibiotics does not enhance the concentration of this carcinogen but, rather, sharply reduces it. The results emphasize the importance of proper antibiotic therapy for the infections to reduce the possibility of the subsequent development of bladder cancer.

Dimethylnitrosamine↗