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Biomedical subjects

R Whittington

Publications and source records attributed to R Whittington.

120 records · Page 7Linked to original sources
PubMed1979

Serodiagnosis of viral hepatitis A by a modified competitive binding radioimmunoassay for immunoglobulin M anti-hepatitis A virus.

A competitive binding radioimmunoassay (CBA) for antibody to hepatitis A virus (HAV) was evaluated and compared with a standard solid-phase radioimmunoassay for anti-HAV, CBA was found to be sensitive and specific for the detection of anti-HAV, as demonstrated by the 98% concordance of CBA and solid-phase radioimmunoassay test results. The standard CBA test was modified for the differential detection of acute (immunoglobulin M) and convalescent (immunoglobulin G) anti-HAV by incorporation of a step in which immunoglobulin G anti-HAV was preferentially absorbed with S. aureus cells (protein A). The modified CBA test was shown to be capable of differentiating between acute- and convalescent-phase sera. The modified CBAM test was able to detect immunoglobulin M anti-HAV up to approximately 4 weeks after the onset of illness.

Acute Disease↗
PubMedDate not supplied

Lucanthone modification of cyclophosphamide toxicity in the Chinese hamster.

The interaction of lucanthone and cyclophosphamide (CYC) was investigated in the Chinese hamster in terms of the LD50/7 and LD50/30. These values may be indicative of gastrointestinal stem cell depletion and bone marrow stem cell depletion, respectively. When a nonlethal dose of 100 mg/kg lucanthone preceded CYC injection, the LD50/7 for CYC reached its minimum value of 470 mg/kg at a treatment interval of 10 hours. Lucanthone administered simultaneously with CYC had no effect on the control LD50/7 of 750 mg/kg, and by 48 hours after lucanthone administration the LD50/7 had returned to the control value. When CYC administration preceded that of lucanthone, the LD50/7 reached a minimum of value of 610 mg/kg at an interval of 5 hours; however, for the entire sequence it was approximately 640 mg/kg over all intervals up to 48 hours. The LD50/30 for CYC was only slightly reduced by the presence of lucanthone, indicating that bone marrow sensitivity to CYC was only marginally affected by lucanthone. These data indicate that lucanthone may interact with CYC damage in much the same way as it interacts with radiation damage, viz, by reducing cellular capacity to accumulate and repair sublethal damage.

Animals↗
PubMedDate not supplied

A sampler of marketing strategies for private practice.

When a practitioner sets out to develop a broad base of influence in order that referral sources are varied and active, marketing must address client, business and professional issues. When resources of money and time become scarce, a satisfied client must be and always will be the best recommendation. To maintain a long line of satisfied clients, credibility, reliability, and reputation must be fostered through personal drive, energy and eternal optimism. Other marketing alternatives must be evaluated for cost effectiveness and ultimate outcomes. All of this can be consumingly fun and rewarding.

Consumer Behavior↗
PubMedDate not supplied

Violence to nurses: prevalence and risk factors.

This article provides a review of current knowledge on the problem of violence to nurses by patients and relatives. In particular, the article discusses the extent of such violence in nursing generally and across different specialties.

Humans↗
PubMedDate not supplied

The use of clinical parameters in an interactive statistical package to predict pathological features associated with local failure after radical prostatectomy for prostate cancer.

The capability of an interactive statistical package (ISP) to predict the patients whose pathologic findings at the time of radical prostatectomy for prostate cancer would require postoperative radiation therapy to prevent local failure is investigated. A retrospective review of the clinical pretreatment factors and pathologic findings of 174 patients with adenocarcinoma of the prostate treated from 1989 to 1993 with radical retropubic prostatectomy was performed and served as a knowledge base of the ISP. The pathologic findings of seminal vesicle involvement, gross transcapsular disease, and positive surgical margins are defined as outcomes associated with a high risk of local failure after radical prostatectomy and, thereby, requiring postoperative radiation therapy to decrease this risk. By using the pretreatment clinical factors including prostate-specific antigen (PSA), Gleason score, clinical stage, and endorectal magnetic resonance imaging (MRI) findings as input to the ISP, patients are identified from a test group of 50 cases with known pathologic outcome who would require postoperative radiotherapy to decrease local failure. Low- (0% to 33%), intermediate- (34% to 67%), and high-risk groups (68% to 100%) for pathologic features associated with local failure were predicted accurately (r > .95) by the ISP for the 50 test cases. Factors identified on univariate analysis by the ISP as significant predictors of local failure postoperatively include PSA > 20 (p < .001), clinical stage (p < .001), MRI finding of gross transcapsular disease (p < .001), MRI finding of seminal vesicle involvement (p < .001), and Gleason score (p < .003).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMedDate not supplied

Application of a statistics-based expert system to provide automated second opinions prior to elective surgery.

Second opinions now are mandated by many funding agencies prior to elective surgery to provide an opportunity to evaluate the indications for surgery and allow an evaluation of the risks of surgery. One difficulty with second opinion programs is the observation that 80% to 95% of all surgical recommendations confirm the need for surgery and the number of patients requiring second opinions represents a significant health care cost. The interactive statistical package (ISP) is a statistics-based decision support system currently used to teach residents medical decision processes. Training an ISP is relatively simple because experts need only define the patient parameters and the allowed values of each parameter. Each expert then sets up a decision tree to represent his or her decision process. The system will then present a series of randomly generated cases to the expert and observe the expert's action. Through Bayesian statistics the system identifies the parameter values that significantly affect the expert's judgment and the direction that they exert on the decision. A decision support system used to evaluate patients with prostate cancer reproduces an expert's treatment selection with an accuracy of 94% on a log rank test when selecting among six treatment options including three different surgical procedures, two different radiation regimens, and palliative therapy. The entire system was trained and validated over 3 weeks, and the accuracy of the system is comparable to the consistency of the expert (90%). Because several experts can review the same patient material and make decisions independently, multiple systems can be created and validated, and operated in parallel.(ABSTRACT TRUNCATED AT 250 WORDS)

Decision Support Techniques↗
PubMedDate not supplied

Neoadjuvant androgen deprivation prior to transperineal prostate brachytherapy: smaller volumes, less morbidity.

PURPOSE: Prostate brachytherapy is becoming increasingly utilized in the definitive treatment of men with early-stage prostate cancer. Others have reported a close relation between total dose to the gland and genitourinary and gastrointestinal toxicity. We tested the hypothesis that 3 months of hormone deprivation would decrease gland size and decrease radioactivity implanted, which would result in less morbidity. Here, we report the toxicity associated with this novel treatment strategy. METHODS: One hundred fifty-five prostate cancer patients underwent ultrasound-guided transperineal implantation of palladium-103 at the Hospital of the University of Pennsylvania between January 1994 and July 1998. All men received at least 3 months of neoadjuvant luteinizing hormone-releasing hormone (LHRH) agonist therapy and were registered in the study. This group of men were compared with 55 men treated at the Hospital of the University of Pennsylvania with brachytherapy alone between December 1991 and December 1993. RESULTS: Compared with men treated with implant alone, men who received LHRH agonist therapy had significantly smaller glands at the time of implant (27.7 cm3 vs 36.3 cm3), required fewer seeds (47.9 vs 83.2), and had significantly less radioactivity implanted (76.3 mCi vs 117 mCi). The genitourinary and gastrointestinal morbidity in the men receiving hormone deprivation was minimal, with long-term side effects occurring in only three patients. In addition, potency was preserved in 83% of men. DISCUSSION: Three months or more of neoadjuvant LHRH agonist therapy before transperineal brachytherapy is safe, significantly reduces the amount of radioactivity implanted, and is associated with very low rates of genitourinary and gastrointestinal toxicity. In addition, potency preservation after combined-modality therapy is excellent and is similar to that of implantation alone. Further studies of this treatment approach are warranted.

Aged↗
PubMedDate not supplied

Seclusion: the use of a stress model to appraise the problem.

This paper raises the issue of the use of seclusion in psychiatric practice by analysing the general theoretical underpinnings and the work of the RCN in this area. The literature suggests an impasse in understanding the thorny problem of the use of controlling measures in the management of the violent and aggressive individual. A new model of understanding is presented which deals with the issue of staff fear in relation to the decision to use seclusion which contributes towards both theory and practice development.

Aggression↗
PubMedDate not supplied

Role of percent positive biopsies and endorectal coil MRI in predicting prognosis in intermediate-risk prostate cancer patients.

PURPOSE: This study was performed to determine the clinical factors that can optimize preoperative staging for clinically localized intermediate-risk prostate cancer patients. MATERIALS AND METHODS: Logistic and Cox regression multivariable analyses were performed on 480 prostate cancer patients whose disease was confined to the prostate to evaluate the ability of clinical stage, prostate-specific antigen (PSA), biopsy Gleason sum, percent positive biopsies, and endorectal coil magnetic resonance imaging (MRI) results to predict pathologic established extracapsular extension, seminal vesicle invasion, and time to postoperative PSA failure in patients with clinically localized prostate cancer. Intermediate risk was defined as PSA 4-10 ng/mL and Gleason sum 5-7; PSA 10-20 ng/mL and Gleason sum < or = 7. RESULTS: Intermediate-risk patients with at least 50%, 67%, 83%, or 100% positive biopsies have disease pathologically confined to the prostate at least 45% of the time; however, if an endorectal coil MRI is positive for either capsular penetration or seminal vesicle invasion, no more than 29% of patients have pathologically determined organ-confined disease. No intermediate-risk patient with both a positive MRI and at least 50% positive biopsies had pathologically determined organ-confined disease. Intermediate-risk patients with less than 50% positive biopsies had pathologically determined organ-confined disease in at least 77% of the cases. CONCLUSIONS: Intermediate-risk patients with an endorectal coil MRI showing extracapsular extension or seminal vesticle invasion are at high risk for early postoperative PSA failure. The concomitant presence of at least 50% positive biopsies increases this risk to unity. Therefore, these patients are not good candidates for surgery alone because of their high risk of extraprostatic disease and should be considered for entry onto phase III trials examining the effect of adding androgen-deprivation therapy to definitive local therapy (external-beam radiation therapy or surgery) on overall survival. The subgroup of intermediate-risk patients likely to benefit from an endorectal coil MRI are those patients with PSA > 10-20 ng/mL; biopsy Gleason score < or = 7, and at least 50% positive biopsies representing approximately 7.5% of the total patient population.

Biopsy↗