Biomedical subjects
R J Friedman
Publications and source records attributed to R J Friedman.
Japanese and United States preschool children's responses to conflict and distress.
Japanese and U.S. preschool children's responses to hypothetical interpersonal dilemmas were examined as a function of culture, gender, and maternal child-rearing values. U.S. children showed more anger, more aggressive behavior and language, and underregulation of emotion than Japanese children, across different contexts of assessment. Children from the 2 cultures appeared more similar on prosocial and avoidant patterns, though in some contexts U.S. children also showed more prosocial themes. Girls from both cultures expressed more prosocial themes and sometimes more anger than boys. Maternal encouragement of children's emotional expressivity was correlated with anger and aggression in children. It was more characteristic of U.S. than Japanese mothers, while emphasis on psychological discipline (reasoning; guilt and anxiety induction) was more characteristic of Japanese than U.S. mothers. The relevance of a conceptual framework that focuses on differences in Eastern and Western cultures in self-construals regarding independence and interdependence is considered.
Histological and mechanical comparison of hydroxyapatite-coated cobalt-chrome and titanium implants in the rabbit femur.
The purpose of this study was to compare hydroxyapatite (HA)-coated titanium (Ti) and HA-coated cobalt-chrome (CoCr) implants in the distal femur of the rabbit by evaluating bone apposition and interfacial shear strength. Bilateral cylindrical implants with a plasma sprayed 50-microns thick HA coating were press-fit into the metaphyseal cancellous bone of the lateral femoral condyles in a transverse fashion, and the animals were sacrificed at 2, 4, and 8 weeks postimplantation. Mechanical strength of the interface between HA and bone was measured using the pushout method. For histologic analysis, the fractional linear extent of bone apposition was quantitated. No differences were found in the interfacial shear strength between the Ti and CoCr at any time period. The amount of bone apposition increased significantly at each time interval for both substrate metals, but there were no significant differences between the two substrates at any of the time periods studied. The HA-coated CoCr implants performed in a similar manner to the HA-coated Ti implants, both mechanically and histologically, suggesting that HA-coated CoCr implants deserve further study as a viable alternative to Ti for the biological fixation of total joint components in orthopaedic surgery.
Management of cutaneous malignant melanoma by dermatologists of the American Academy of Dermatology. I. Survey of biopsy practices of pigmented lesions suspected as melanoma.
BACKGROUND: The incidence of malignant melanoma (MM) has rapidly increased during the past five decades. Relatively little information is available on whether the role of the dermatologist has increased concomitantly in the surgical management of this cancer. OBJECTIVE: Our purpose was to learn how members of the American Academy of Dermatology (AAD) treat patients with lesions highly suspected as being MM and how the management of these patients may have changed over the past decade. This, the first of a two-part series, concerns biopsies. METHODS: The data for the study were collected by means of a questionnaire that was sent to all members of the AAD practicing in the United States (N = 7412). RESULTS: A total of 2991 valid questionnaires were returned, a response rate of 40%. The majority of respondents (89% in 1982; 90% in 1992) stated that they performed the biopsies of pigmented lesions suspected of being MMs. Excisional biopsy was the preferred technique (58% in 1982; 68% in 1992). The type of biopsy and who performed the initial biopsy of a suspected MM were associated with the following factors: (1) the number of years in practice, (2) the type of practice, and (3) whether the dermatologist subsequently performed the definitive surgery for the MM. Regional variations in biopsy practices were also noted. CONCLUSION: Most AAD dermatologists who responded to the questionnaire perform the biopsies of lesions highly suspected of being MM. During the last decade an increasing proportion of dermatologists are performing excisional biopsies rather than other types of biopsies for such lesions.
Management of cutaneous malignant melanoma by dermatologists of the American Academy of Dermatology. II. Definitive surgery for malignant melanoma.
BACKGROUND: During the past few decades there has been increasing interest and training in dermatologic surgery. OBJECTIVE: Our purpose was to determine to what extent members of the American Academy of Dermatology (AAD) are involved in the surgical management of patients with malignant melanomas (MMs), comparing 1982 with 1992. METHODS: Members of the AAD practicing in the United States (N = 7412) were sent a questionnaire that surveyed their role in the definitive treatment of patients with MMs and the surgical margins of normal-appearing skin that they used or recommended for melanomas of various thicknesses. RESULTS: Sixty-four percent of the respondents stated that they performed the definitive surgery for in situ melanoma in 1992, a 14% increase from 1982. Although a significantly greater percentage of dermatologists were performing the definitive surgery for invasive melanoma in 1992 (28%) compared with 1982 (14%), the majority continued to refer their patients to surgical colleagues for definitive treatment. There has been a narrowing of surgical margins recommended or used for melanomas of all thicknesses. In addition, regional differences of the role of the dermatologist in surgical management of patients with MM were observed. CONCLUSION: An increasing proportion of dermatologists are involved in the surgical management of patients with MMs. Most dermatologists appear to be in accord with the guidelines for surgical margins currently recommended in the literature.
The ABCDs of melanoma: why change?
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Application of a fluorescent redox dye for enumeration of metabolically active bacteria on albumin-coated titanium surfaces.
A bacterial staining method using fluorescent redox dye 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) is described for quantifying actively respiring bacteria that adhere to commercially pure titanium surfaces coated with cross-linked albumin. This has not been possible to date using ordinary DNA stains such as propidium iodide (PI) or Hoechst, both of which produce a very bright background. With this technique, it was demonstrated that the cross-linked albumin inhibited the adherence of Staphylococcus aureus and Staph. epidermidis to the titanium surface.
Use of supplemental steroids in patients having orthopaedic operations.
It is commonly thought that patients receiving exogenous glucocorticoids have suppression of the hypothalamic-pituitary-adrenal axis and need high supplemental doses of exogenous glucocorticoids (so-called stress steroids) to meet the demands of operative stress. Several reports have suggested that clinically important suppression of the hypothalamic-pituitary-adrenal axis is extremely uncommon and that the levels of glucocorticoids required for stress are much lower than previously believed. A prospective study of twenty-eight patients who had thirty-five major orthopaedic operations was conducted. No patient received stress steroids; they were given only the baseline immunosuppressive doses of glucocorticoids (mean dose, ten milligrams of prednisone). Clinical information (based on regular physical examinations for signs and symptoms of hypotension, myalgia, arthralgia, ileus, and fever) and laboratory data (serum sodium levels, eosinophil count, and twenty-four-hour urinary free-cortisol levels, determined at perioperative and non-stress postoperative time-periods) were obtained to document any evidence of adrenocortical insufficiency. There was no such evidence in any of the patients, who were monitored during their entire hospitalization. The levels of twenty-four-hour urinary free cortisol showed that all patients had endogenous adrenocortical function and, when this information was considered together with the clinical outcome, it was concluded that this level of function was sufficient to meet the demands of operative stress. Adrenocortical insufficiency in patients who have orthopaedic operations without receiving supplemental stress steroids appears to be much less common than previously thought. While biochemical testing of the function of the hypothalamic-pituitary-adrenal axis may sometimes reveal evidence of adrenal insufficiency, these tests do not predict the clinical outcome and may be too sensitive to guide decisions regarding treatment. Supplemental exogenous stress glucocorticoids may not be needed to meet the demands of operative stress in these patients.
Steroid-induced osteonecrosis of the humeral head.
Steroid-induced osteonecrosis is a disease of modern medicine. Prevention remains the hallmark of management; however, as long as there are medical conditions requiring steroid therapy, osteonecrosis will remain a problem. An understanding of the pathophysiology, in addition to the clinical and radiographic manifestations of this disease process, will aid the physician in the unique challenge of diagnosing and treating osteonecrosis of the humeral head.
Magnetic resonance imaging: a bright future despite health care's cost-conscious environment.
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Biomechanics of total shoulder arthroplasty: a preoperative and postoperative analysis.
To successfully perform a total shoulder arthroplasty, it is essential to understand the normal anatomy and biomechanics of the shoulder joint. Currently, nonconstrained prostheses offer the most consistent and durable long-term results, allowing for the restoration of normal anatomy and motion close to that of the normal shoulder joint. To determine the effects of the disease process, surgical technique, and postoperative rehabilitation on glenohumeral biomechanics after nonconstrained total shoulder arthroplasty, a prospective clinical trial was undertaken to evaluate preoperative and postoperative shoulder motion clinically and roentgenographically in nine patients with severe arthritis. Preoperatively, the ratio of glenohumeral to scapulothoracic motion was 1:2; for every degree of glenohumeral movement there were two degrees of scapulothoracic motion. This was associated with significant pain and decreased motion in the shoulder and represented the patient's attempt to immobilize the glenohumeral joint for pain relief and maximize shoulder movement with scapulothoracic motion. After total shoulder arthroplasty, significant improvements were observed in pain relief, motion, and function; however, the ratio of glenohumeral to scapulothoracic motion was not significantly different. The abnormal ratio indicates that less motion occurs between the prosthetic components compared with a normal joint, whereas scapulothoracic motion is unchanged. Abnormal shoulder biomechanics seem to be a function of the underlying disease process and were not restored after total shoulder arthroplasty. Despite the successes to date, improvements on the current state of the art are still needed, and will occur with better understanding of the complex biomechanics of the shoulder joint.
Stress steroids are not required for patients receiving a renal allograft and undergoing operation.
BACKGROUND: It is commonly believed that patients receiving exogenous glucocorticoids have hypothalamic-pituitary-adrenal (HPA) axis suppression and require exogenous, supplemental, high-dose stress glucocorticoids to meet the demands of operative or other stress. Several recent reports suggest both that clinically important HPA axis suppression is extremely uncommon and that the levels of glucocorticoids required for stress are much lower than previously believed. In addition, the high doses of steroids currently used for stress prophylaxis may actually increase morbidity and mortality. STUDY DESIGN: To test the need for stress steroids, a prospective study of 52 recipients of a renal allograft who underwent 58 operative procedures was conducted. No patient received stress steroids but only baseline, immunosuppressive doses of glucocorticoids. Clinical (hypotension, myalgias, arthralgias, ileus, and fever) and laboratory (serum sodium, eosinophil count, and 24-hour urinary-free cortisol from perioperative and nonstressed time periods) data were obtained to document evidence for adrenocortical insufficiency. RESULTS: There was no clinical or laboratory evidence for adrenocortical insufficiency in any of the patients. Twenty-four hour urinary-free cortisol levels showed that all patients had endogenous adrenocortical function and, combined with clinical outcome, this function was sufficient to meet the demands of stress. CONCLUSIONS: Adrenocortical insufficiency is much less common in recipients of a renal allograft than previously thought. Supplemental exogenous stress glucocorticoids are not required to meet the demands of operative stress in these patients. While biochemical testing of HPA axis function may sometimes reveal evidence for adrenal insufficiency, these tests do not predict clinical outcome and are far too sensitive to guide therapy.
Glenohumeral instability.
Glenohumeral instability can be defined as pain associated with loss of shoulder function due to excessive translation of the humeral head on the glenoid fossa. It can be classified according to many factors, such as direction, degree, mechanism, and frequency. A thorough understanding of the anatomy and biomechanics of the shoulder joint as they relate to instability is helpful in understanding the pathophysiology of this condition. All components of the instability must be correctly diagnosed so that appropriate treatment can be selected. Clinical examination is most important in making the correct diagnosis, but plain radiographs, arthrography, computed tomography, magnetic resonance imaging, examination under anesthesia, and arthroscopy can be helpful in difficult and challenging cases. Conservative treatment with a rehabilitation program can be successful in a large percentage of cases and should be the initial approach for most patients. Operative treatment is based on the direction and type of instability and is recommended only after an adequate trial of conservative therapy has failed to improve recurrent instability.
Long-term durability of the interface in FRP composites after exposure to simulated physiologic saline environments.
Fiber/matrix interfacial bond strength significantly influences the mechanical behavior of fiber-reinforced polymer (FRP) composites. Interfacial bond strength durability is therefore particularly important in the development of FRP composites for implant applications where diffused moisture may potentially weaken the material over time. In this study, the long-term durability of interfacial bonding in carbon fiber/380 grade polyetheretherketone (C/PEEK) and carbon fiber/polysulfone (C/PSF) composites was investigated after exposure to hygrothermal environments. A single fiber pull-out test was used to quantitatively determine the ultimate bond strength (UBS) of the samples following exposure. Samples were tested at three temperatures (37, 65, and 95 degrees C) for six time periods (0-5000 h) and in two environments (dry and physiologic saline-immersed). A mathematical model based on nth order chemical reaction kinetics was applied to describe the long-term durability of the interface. The results of this study indicate that interfacial bond strengths in C/PSF and C/PEEK (380 grade) composites are significantly decreased by exposure to physiologic saline and are functions of both time and temperature. For each material, the kinetics of degradation analysis predicts further bond strength losses following initial saturation, which then stabilizes at temperature-dependent equilibrium bond strength levels.
Silicone breast prostheses implantation and explanation.
Breast implants have been used for augmentation and reconstruction for a 30-year period. Standard techniques have been used for the successful placement of mammary prostheses to enhance or replace breast tissue. All breast implants are surrounded by a capsule. The most common complication of breast implant surgery is hardening and contracture of the capsule. Explanation of implants is indicated for implant rupture, infection, extrusion, siliconoma, breast pain, painful capsular contracture, malposition, significant patient fear, and systemic symptoms thought secondary to implants. A number of alternatives are available for postexplant reconstruction, including myocutaneous flaps and free tissue transfers.
Natural history of uncorrected flexion contractures following total knee arthroplasty.
Over a 2-year period, 29 patients were identified that had preoperative flexion contractures less than 30 degrees and were not fully corrected to neutral following total knee arthroplasty. They were followed after surgery at 3, 6, and 12 months, and yearly thereafter with complete clinical and roentgenographic examinations to determine the natural history of the flexion contracture and its effect on the clinical outcome. The mean age of the 10 women and 19 men was 66 years (range, 47-80 years). The mean preoperative flexion contracture was 11 degrees (range, 5 degrees-30 degrees). The mean follow-up period was 33 months (range, 24-60 months). The mean values of the flexion contractures at each follow-up period were; immediately after surgery, 10.5 degrees; at 3 months, 5 degrees; at 6 months, 2 degrees; at 12 months, 1 degree; and at 24 months, 1 degree (P < .0001). Resolution of the flexion contracture did not vary between patients under and over the age of 65 years. There was no statistically significant difference in the residual flexion contracture when knees with preoperative contractures from 0 degrees to 14 degrees and 15 degrees to 30 degrees were compared. The clinical outcome was not affected by the residual flexion contracture after 6 months of follow-up evaluations. Significant improvements can occur after surgery with rehabilitation, and it appears that complete intraoperative correction is not necessary. There appears to be no difference in the natural history of flexion contractures with regard to age or severity up to 30 degrees.
Lack of selective attendance of participants at skin cancer/melanoma screening clinics.
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Production of a standard closed fracture in the rat tibia.
In order to develop a technique for producing a standard closed transverse fracture in the rat tibia, the method of Bonnarens and Einhorn was modified and tested on 176 tibiae. A 0.9-mm Kirschner wire was inserted percutaneously near the tibial tuberosity into the intramedullary canal, and a tibial fracture was created at the junction of the middle and distal third of the tibia with a blunt guillotine driven by a dropped weight. Radiographs confirmed the production of a highly reproducible transverse mid-shaft tibia fracture in 90% of the fractures. Minimal comminution of the fracture or angulation of the Kirschner wires resulted. The Kirschner wires were removed without difficulty after the rats were put to death and did not disturb the fracture site. Mechanical testing and histological studies showed that a standard fracture healing process was obtained by using this method. The results indicate that this modified method creates a standard, reproducible transverse closed fracture of rat tibia.