Short communications: an ear-attached accelerometer detects effects of regrouping on lying, rumination, and activity times in calves.

The objective of this study was to use a sensor-based accelerometer (ACC) to identify changes in lying, rumination, and activity times in weaned calves during the moving and regrouping process. Overall, 270 healthy Holstein calves (from approximately 16 regrouping events) at the age of approximately 4 months were enrolled and equipped with an ear-attached ACC (SMARTBOW, Smartbow GmbH/ Zoetis LLC). Sensor data were recorded for 5 d before (d -5) until 4 d after moving and regrouping (d 4). The day of regrouping was defined as d 0. Acceleration data were continuously processed by specific algorithms (developed by SMARTBOW) for lying, rumination, and activity. Lying, rumination, and activity times were averaged from d -5 to d -3 to generate a baseline value for each parameter. Parameters on d 0 to d 4 after regrouping were compared to this baseline. All parameters showed significant changes compared with the baseline at d 0. Significant decreases in rumination and inactive times were seen up to d 2. Lying time was significantly lower until d 3. The study results indicate that the ACC can be used to monitor the disruptive effects of regrouping on lying and rumination behaviors. Further research is necessary to elucidate how these changes have an impact on health, performance, and welfare and to evaluate how to reduce these potentially negative effects.

Drug release from lipid-based implants: elucidation of the underlying mass transport mechanisms.

The aim of this study was to better understand the mass transport mechanisms involved in the control of drug release from lipid-based implants. Different types of triglyceride-based cylinders were prepared by compression. Glycerol-trilaurate, -trimyristate, -tripalmitate and -tristearate were used as model lipids, lysozyme and pyranine as model drugs. The effects of several formulation and processing parameters on the resulting drug release kinetics in phosphate buffer pH 7.4 were studied and the obtained results analyzed using Fick's second law of diffusion. Interestingly, lysozyme release from implants prepared by compression of a lyophilized emulsion (containing dissolved drug and lipid) was found to be purely diffusion-controlled, irrespective of the type of triglyceride. In contrast, the dominating release mechanism depended on the type of lipid in the case of pyranine-loaded implants prepared by compression of a lyophilized lipid-drug solution: with glycerol-trilaurate and -tristearate the systems were found to be purely diffusion-controlled, whereas also other mass transport phenomena are of importance in glycerol-trimyristate and -tripalmitate-based devices. Similarly, changes in the size of the compressed lipid-drug particles, drug loading and compression force significantly affected the underlying release mechanisms. The addition of a drug-free, poly(lactic-co-glycolic acid) (PLGA)-based coating around the implants delayed the onset of pyranine release for about 20 days. Interestingly, the subsequent drug release was purely diffusion-controlled, irrespective of the type of triglyceride. Also the addition of different amounts (and particle size fractions) of saccharose to pyranine-loaded implants led to purely diffusion-controlled drug release.

Programmable implants--from pulsatile to controlled release.

The aim of this study was to develop programmable implants with a reproducible delayed onset of release followed by several weeks of controlled release. For this purpose, a drug-loaded core was embedded into a drug-free bulk-eroding poly(D,L lactic-co-glycolic acid) or poly(D,L lactic acid) mantle. The manufacturing procedure was established and optimized for three mantle materials, which showed delay times ranging from 7 to 83 days. Triglycerides with fatty acid chain lengths from C12 to C18 were investigated as core materials, producing release periods from 2 to 16 weeks. Concomitantly, applying a convolution/deconvolution model showed the possibility of theoretical prediction of the resulting release profiles.

Biocompatibility and erosion behavior of implants made of triglycerides and blends with cholesterol and phospholipids.

Triglycerides are a promising class of material for the parenteral delivery of drugs and have become the focus of tremendous research efforts in recent years. The aim of this study was to investigate the biocompatibility of glyceroltripalmitate as well as the influence of cholesterol and distearoyl-phosphatidyl-choline (DSPC) on the erosion behavior of the lipid. For these investigations, two in vivo studies were carried out, in which cylindrical matrices of 2 mm diameter were manufactured and subcutaneously implanted in immunocompetent NMRI-mice. After excision of the implants, tissue reactions of the animals as well as changes in the weight, shape and microstructure of the implants were investigated. The triglyceride and cholesterol showed good biocompatibility, as indicated by their minimal encapsulation in connective tissue and the absence of inflammatory reactions. Increasing the levels of phospholipid in the implants, however, led to an increased inflammatory reaction. In contrast to cholesterol, which did not affect erosion, the incorporation of DSPC into the triglyceride matrices led to clearly visible signs of degradation.

Paclitaxel-loaded microparticles and implants for the treatment of brain cancer: preparation and physicochemical characterization.

The aim of this study was to prepare different types of paclitaxel-loaded, PLGA-based microparticles and lipidic implants, which can directly be injected into the brain tissue. Releasing the drug in a time-controlled manner over several weeks, these systems are intended to optimize the treatment of brain tumors. The latter is particularly difficult because of the blood-brain barrier (BBB), hindering most drugs to reach the target tissue upon systemic administration. Especially paclitaxel (being effective for the treatment of ovarian, breast, lung and other cancers) is not able to cross the BBB to a notable extent since it is a substrate of the efflux transporter P-glycoprotein. Both, biodegradable microparticles as well as small, cylindrical, glycerol tripalmitate-based implants (which can be injected using standard needles) were prepared with different paclitaxel loadings. The effects of several formulation and processing parameters on the resulting drug release kinetics were investigated in phosphate buffer pH 7.4 as well as in a diethylnicotinamide (DENA)/phosphate buffer mixture. Using DSC, SEM, SEC and optical microscopy deeper insight into the underlying drug release mechanisms could be gained. The presence of DENA in the release medium significantly increased the solubility of paclitaxel, accelerated PLGA degradation, increased the mobility of the polymer and drug molecules and fundamentally altered the geometry of the systems, resulting in increased paclitaxel release rates.

Tolerance of pelvic normal tissues to hyperfractionated radiation therapy: results of Protocol 83-08 of the Radiation Therapy Oncology Group.

A prospective, centrally randomized Phase I/II trial of hyperfractionation in definitive radiation therapy for locally advanced squamous and transitional cell carcinoma of the bladder was conducted by the Radiation Therapy Oncology Group (RTOG) from April 1983 through June 1986. Patients with T3-4 and T2 N+ (AJC) histologically-confirmed cancer of the bladder received twice daily radiation therapy with 1.2 Gy per fraction and a minimum of 4 hr between fractions. All patients received a whole pelvic total dose of 50.4 Gy: Total doses to reduced volumes were 60.0 Gy, 64.8 Gy, or 69.6 Gy. Of 54 patients entered, 50 were eligible. An unbalanced treatment assignment was used: Nine patients received 60.0 Gy, 15 patients received 64.8 Gy and 26 received 69.6 Gy. Performance status (Karnofsky) was 90-100 in 72% of patients and 92% had transitional carcinoma. Eighty percent of tumors were T3 or T4. Observation of at least 18 months was available for 26 patients. Grade 3 acute reactions (within 90 days) were reported in eight patients (one at 60.0 Gy, three at 64.8 Gy and four at 69.6 Gy). Five patients experienced a total of seven major late effects--four Grade 3 and three Grade 4. The cumulative probability of Grade 3 and 4 late complications of treatment for the 46 patients at risk for late complications was 5% +/- 3% at 6 months, 7% +/- 4% at 12 months, and 10% +/- 5% at 18 and 24 months. The cumulative probability of Grade 3 or 4 late complications for patients who received a total dose of 69.6 Gy was 5% +/- 4% at 6 and 12 months and 11% +/- 8% at 18 and 24 months. Only one patient who experienced major late effects was also reported to have major acute reactions. Comparisons of survival of patients treated in the current study with those who received 60 Gy in 30 fractions in 6 weeks in RTOG Protocol 71-04, did not suggest any deleterious effects from hyperfractionated radiation therapy to the pelvis. The normal pelvic tissues tolerated hyperfractionated radiation therapy sufficiently well to justify exploring it, alone and with brachytherapy, in other pelvic tumors.

Prophylactic irradiation of the para-aortic lymph node chain in stage IIB and bulky stage IB carcinoma of the cervix, initial treatment results of RTOG 7920.

From November 1979 to October 1986, 367 patients were entered onto RTOG 7920 and randomized to receive either pelvic irradiation alone or pelvic plus para-aortic radiation. Patients with Stage IIB cervical carcinoma who had not undergone curative surgery and patients with Stages IB and IIA cervical carcinoma who were determined by digital exam to have primary tumors measuring 4 cm or greater in lateral dimension were eligible for this study. Clinically apparent or surgically involved para-aortic nodes were reason for exclusion from the study. Pelvic irradiation consisted of 1.6-1.8 Gy per day for 5 days per week to a total of 40-50 Gy. Para-aortic irradiation delivered 44 to 45 Gy in 1.6-1.8 Gy per day, 5 days per week. Pelvic irradiation was to be completed in 4 1/2 to 6 1/2 weeks and para-aortic irradiation in 4 1/2 to 5 1/2 weeks. Intracavitary brachytherapy delivered a total of 4000-5000 mg hr of radium-equivalents or 30-40 Gy to point A. Patients were stratified prior to random treatment assignment by histology, para-aortic nodal status (negative vs. unevaluated), and FIGO stage. As of June 1, 1989, 30 cases were excluded, including five patients who were inevaluable. Two patients who refused the assigned treatment were also excluded. Therefore, a total of 330 cases were analyzable. At 5 years the estimates of survival, the primary endpoint, for the pelvic only and pelvic plus para-aortic irradiation arms are 55% and 65%, respectively (p = 0.043). Several secondary endpoints were also analyzed. Estimates for loco-regional control at 5 years are, for pelvic irradiation only, 66%, and for pelvic plus para-aortic irradiation, 75% (p = 0.21). Distant metastases are estimated in 32% of pelvic irradiation only patients and 25% of pelvic plus para-aortic irradiation patients at 5 years (p = 0.17). When the first disease failure patterns are examined, more patients fail distally when treated only with pelvic radiation than when using pelvic plus para-aortic fields (p = .04). In analysis of patients with grade 3 (severe), grade 4 (life-threatening), and grade 5 (fatal complications), 8% of the patients in both groups had grade 3 severe complications. In the pelvic plus para-aortic group, 11 patients had grade 4 and 2 had grade 5 complications, whereas 6 had grade 4 and none had grade 5 in the pelvic only treatment group.(ABSTRACT TRUNCATED AT 400 WORDS)

Phase II study of multiple daily fractionations in the palliation of advanced pelvic malignancies: preliminary report of RTOG 8502.

This Phase II protocol was designed around the format of a previously reported study for the palliation of advanced pelvic malignancies (RTOG 7905). The large dose per fraction (1000 cGy) of the first study unexpectedly demonstrated frequent late gastrointestinal toxicity and was replaced in the present study by 2 days of twice daily fractionation (370 cGy/fraction totaling 1480 cGy/course) based on linear quadratic consideration of acute and late toxicities. The interval between courses of 4 weeks was retained and the total dose for three courses was 4440 cGy. A total of 152 patients were entered of which 142 have sufficient follow-up information for analysis. Fifty-nine percent of the patients completed all three courses, 20% completed two courses, and 20% received only one course. The primary sites were: gynecological (39.4%); colorectal (32.4%); genitourinary (24.7%); and other (2.8%). The best overall response was: complete remission (10%); partial remission (22%); no change (24%); progression (10%); and unknown (27%). For the patients completing all three courses, the response was: complete remission (14%); partial remission (31%); no change (40%); progression (7%); and unknown (8%). Median survival was 4.5 months and the actuarial survival at 12 months is 19%. In RTOG 7905, 90% of the late toxicities appeared by 12 months. For RTOG 8502, there were 32 patients alive at 9 months and 19 patients alive at 12 months available for evaluation of late toxicity. There has been one late grade 3 GI toxicity reported and only one acute grade 3 gastrointestinal toxicity. Even if the true rate of late toxicity for 8502 were 20%, the chance of seeing none or one toxicity would be 0.007. This toxicity report represents a marked reduction of the grade 3 and 4 late toxicity seen in RTOG 7905 (37% at 9 months and 45% at 12 months) without lowering the tumor response rate. The interval between courses in both protocols allows for potential tumor proliferation. To test for the effect of tumor proliferation, RTOG 8502 is continuing as a Phase III randomization between 4 weeks and 2 weeks separation.

194 hepatocellular cancers treated by radiation and chemotherapy combinations: toxicity and response: a Radiation Therapy Oncology Group Study.

Hepatocellular carcinoma is known to have a doubling time of approximately 41 days. This rapid cell division suggested that hyperfractionated radiation and chemotherapy might add an advantage in gaining remission of this malignancy. One hundred and thirty-five patients (70% with metastasis and/or previous treatment) were prospectively treated with single daily fractions to the liver (3.0 Gy external beam radiation, total dose 21.0 Gy), and chemotherapy for hepatocellular carcinoma. The low dose chemotherapy used in conjunction with the radiation was 2 hr before treatment on days 1, 3, 5, and 7 and consisted of Adriamycin, 15 mg IV and 5-FU, 500 mg IV. These patients were compared to a second group of 59 patients (80% with metastases and/or previous treatment) treated using the same chemotherapy regimen but using hyperfractionated whole liver external beam irradiation (1.2 Gy twice daily, 4 hr between treatments, 5 days per week to 24.0 Gy, 10 MV photons). Response was determined by CT scan tumor volumetric analysis. The response rate for the single daily fraction patient group was 22% and for the new hyperfractionated group, 18% (p = 0.68). Toxicity was evaluated by RTOG criteria. The grade 4 hematologic toxicity noted in the daily fraction patient group was 6%. Among 59 patients treated with the hyperfractionated liver irradiation, 2% experienced grade 4 hematologic toxicity. Esophagitis occurred in 1% of patients in the standard fractionation group and 19% in the hyperfractionated group (p = 0.0001). Grade 1-4 thrombocytopenia occurred in 49% of patients in the conventional group and 68% in the hyperfractionated group (p = 0.03). Normal liver volume changes with treatment were measured with CT scan tumor volumetric analysis. The hyperfractionated group experienced a median of 11 cc increase in liver volume and the conventional group a 46 cc decrease, but the difference was not significant. Hyperfractionated radiation did not demonstrate a significant benefit over standard daily radiation, but acute toxicity appeared to be higher.

Prognostic factors in unresectable hepatocellular cancer: Radiation Therapy Oncology Group Study 83-01.

The Radiation Therapy Oncology Group (RTOG) conducted a Phase I/II study in hepatocellular cancer that closed on September 9, 1987 and some results presented previously. Here, 17 patient characteristics are evaluated to identify any of prognostic significance. Two hundred sixteen patients were entered and 198 (74% with metastases and/or previous chemotherapy) were evaluable. Treatment began with an induction regimen of external beam radiotherapy to the liver (21.0 Gy, 3.0 Gy/Fx, 10 MV photons, 4 days per week) with low-dose chemotherapy (5-Fluorouracil (FU), 500 mg, i.v.; Doxorubicin, 15 mg, i.v.) on treatment Days 1, 3, 5 and 7. In the later stages of these studies, 56 patients received external beam radiotherapy as hyperfractionated treatment (1.2 Gy twice daily, 4 hours separation, 5 days per week, 24.0 Gy total) with similar chemotherapy. One month following induction therapy, cycles of radiolabeled antibody therapy were given every 2 months. Each cycle was derived from a different species of animal and consisted of 30 mCi I-131 antiferritin, Day 0, and 20 mCi, Day 5. On Day -1, 5-FU, 500 mg, and Adriamycin, 15 mg, were administered. The overall median survival for the entire group, including previously treated patients, was 4.9 months. The median survival for alpha-fetoprotein (AFP) - patients not previously treated was 10.5 months. Median survival for all AFP - patients was 8.5 months and for all AFP + patients was 4.6 months (p = 0.006). Of the 17 pretreatment characteristics investigated for prognostic value Karnofsky Performance Score (KPS) (80-100 vs. less than 80) (p = 0.0001), presence/absence of ascites (p = 0.0002), bilirubin level (less than 1.5 vs. greater than or equal to 1.5) (p = 0.018), SGOT (less than or equal to 35 vs. greater than 35) (p = 0.001); alkaline phosphatase (less than or equal to 95 vs. greater than 95) (p = 0.008) were found to be significant independently using a multivariant regression model. The relative risk of dying for the unfavorable component of each of these characteristics was 2.2, 2.0, 1.5, 1.9 and 1.7, respectively. Good and poor prognostic groups were then defined and compared to a similar patient population (RTOG study 83-19) with confirmation of the validity of the model. When stratification for these overpowering clinical factors was incorporated, AFP status was again significant with a relative death rate 1.80 times higher for AFP+ patients. Our recommendations for structuring future prospective randomized trials are discussed and include stratification by AFP status.

Accelerated fractionation radiation therapy for liver metastases: selection of an optimal patient population for the evaluation of late hepatic injury in RTOG studies.

The palliation of hepatic metastases represents a major therapeutic problem in oncology. The generally unfavorable prognosis of patients with liver metastasis may complicate the evaluation of the efficacy and toxicity of various therapeutic modalities. The Radiation Therapy Oncology Group (RTOG) is evaluating new accelerated fractionation schemes for hepatic irradiation. In designing this study it became necessary to identify a favorable subpopulation of patients with an expected median survival of 6 months in whom the late effects of treatment could be evaluated. Data from two RTOG liver metastases studies (7605 and 8003) were analyzed using multi-variate techniques. Cases with a serum bilirubin level of greater than 1.5 mg%, performance score of less than 50, and gastric or pancreatic primary carcinomas were initially excluded because of the adverse influence of these factors on survival. One hundred and ninety cases met the criteria for inclusion in this analysis. A loglinear model was used to identify the patient characteristics associated with a favorable prognosis for survival. These included a performance score of 80-100, colorectal carcinoma primary, and no extrahepatic metastases. A logistic regression equation was derived and confirmed that the probability of surviving at least 6 months depended on the effects of performance score, primary site and the presence or absence of extra-hepatic metastases. Patients with all three favorable factors constituted 30% of the evaluable study population and had a predicted survival of 50% at 6 months. A patient population with these characteristics will be used to study the late effects of accelerated fractionated radiation therapy on the liver.

Identification of heavy drinkers using a combination of laboratory tests.

OBJECTIVE: This study derived and evaluated a model that used results of commonly performed laboratory tests to identify men who are heavy drinkers. METHOD: The results of 40 commonly available laboratory tests were obtained on a diverse sample of 426 heavy drinkers and 188 light drinkers. A logistic regression equation for identifying heavy drinkers was derived in a training data set of 411 subjects and tested in a validation data set of 203 subjects. RESULTS: Ten laboratory measurements were included in the final regression equation: chloride, sodium, ratio of direct to total bilirubin level, blood urea nitrogen, high density lipoproteins, monocyte count, phosphorus, platelets, aspartate aminotransferase, and mean corpuscular hemoglobin. In the validation data this model correctly identified 98% of the 161 heavy drinkers and 95% of the 42 light drinkers. Other models reported in previous literature were applied to these subjects and did not perform as well. The model performed better for subjects of lower socioeconomic status. CONCLUSIONS: The laboratory tests in our model may help identify heavy drinkers. The performance of models to identify heavy drinkers depends on the demographic characteristics of the subjects.

Long-term follow-up of iatrogenic phototoxicity.

OBJECTIVE: To evaluate the outcomes of a group of patients who suffered iatrogenic phototoxic injury. METHODS: The medical records of 24 patients (24 eyes) with iatrogenic phototoxicity from 3 medical centers were reviewed. We report the findings from long-term follow-up of these patients with particular attention to visual outcome, type and duration of procedure, and location of the phototoxic lesion. RESULTS: Phototoxic injury occurred after anterior segment surgery in 20 eyes and after vitrectomy in 4 eyes. The mean duration of surgery was 109 minutes; there was no statistically significant difference in duration between the anterior segment procedures and the vitrectomies. Mean final visual acuity was 20/40 for all cases (range, 20/15 to counting fingers) and 20/25 for all anterior segment cases. In vitrectomized eyes, the mean final visual acuity was 20/900. Phototoxic lesions tended to spare the fovea after anterior segment surgery and involve the foveal center after vitrectomy. CONCLUSIONS: In general, patients who suffer phototoxicity do well, and the prognosis is good for extrafoveal lesions. Foveal injury, which often occurs with vitrectomy, usually leads to a worse visual outcome. The development of choroidal neovascularization may have an effect on the ultimate visual outcome as well.

Comparison of pneumatic retinopexy and scleral buckling in the management of primary rhegmatogenous retinal detachment. Southern Wisconsin Pneumatic Retinopexy Study Group.

PURPOSE: To compare pneumatic retinopexy and scleral buckling for repair of primary rhegmatogenous retinal detachment with respect to visual outcome, single-procedure reattachment rate, and development of proliferative vitreoretinopathy. METHODS: A consecutive series of eyes initially treated with pneumatic retinopexy (n = 56) between March 1986 and February 1996 were compared with a selected group of eyes treated with scleral buckling (n = 86) with similar location and distribution of retinal breaks and absence of proliferative vitreoretinopathy. A regression model was developed to adjust for underlying differences between treatment groups, resulting in a cohort of 50 eyes in each group for final comparison. A minimum follow-up of 6 months was obtained. RESULTS: Single-procedure reattachment rate was significantly higher for scleral buckle eyes (42 of 50 eyes, 84%) than for pneumatic retinopexy eyes (31 of 50 eyes, 62%; P < or = .01). Correspondingly, reoperation rate was significantly higher for pneumatic retinopexy eyes (19 of 50 eyes, 38%) than for scleral buckle eyes (7 of 50 eyes, 14%; P < or = .01). Multiple regression analysis evaluating perioperative factors demonstrated that the use of pneumatic retinopexy was the sole factor predictive of retinal detachment after a single procedure (relative odds = 2.20, P = .02). Final reattachment rate, after reoperations, was 98% (49 of 50 eyes) in each group. Except for nonphakic eyes, final visual outcome and rate of postoperative proliferative vitreoretinopathy development did not differ significantly between the two procedures. CONCLUSIONS: In phakic eyes, pneumatic retinopexy was associated with a significantly higher reoperation rate than scleral buckling, but resulted in equivalent final visual outcome and reattachment rate after reoperations. If used, it must be incorporated into a strategy in which patient and physician are prepared for a greater chance of reoperation compared to initial management with scleral buckling.

A sequential chart for the audit-based evaluation of screening mammogram interpretation.

RATIONALE AND OBJECTIVES: Auditing has received much attention recently as a method for radiologists to use to evaluate their interpretation of screening mammograms. U.S. Food and Drug Administration regulations require that some sort of audit be in place before a mammography screening facility can receive accreditation. Auditing presents a unique opportunity to monitor accuracy continually and identify problems early. Audit data present unique challenges, however, and appropriate methods must be used to control the risk of errors. MATERIALS AND METHODS: This article introduces a simple method for the task of deciding if a radiologist yields an acceptable positive predictive value based on audit. The method is based on "sequential" decision-making techniques that have found wide application in quality control problems. These techniques are developed for diagnostic radiology and embodied in an easy-to-use decision-making chart. RESULTS: Several examples, based on audit data from actual mammography facilities, provide insights into the use of these charts and the influence of (a) the selection of standards, (b) the selection of error risks, and (c) radiologist variability. The examples also serve to demonstrate another important property of this method--that is, it specifies the minimum amount of data that has to be collected before any decision can reliably be made. CONCLUSION: The chart presented in this article provides a method by which audit data can be used objectively to evaluate the accuracy of screening mammogram interpretation. The method controls the risk of either falsely accepting an unqualified radiologist or falsely rejecting a qualified radiologist. It should be a useful tool to radiologists who must evaluate their own practices.

Improvement in resource utilization after development of a clinical pathway for patients with pressure ulcers.

Clinical pathways are interdisciplinary patient care plans intended to reduce variance and improve quality of care while lowering health care cost. This study was undertaken to determine whether the development of a clinical pathway for care of patients with pressure ulcers can indeed decrease health care costs while preserving quality of care. A clinical pathway for surgical reconstruction of pressure ulcers was developed by standardizing the current practices of our plastic surgeon group. The pathway provided direction in optimal scheduling of physician interventions along with nursing, physical and occupational therapies, and spinal cord rehabilitation interventions. It covered all potential elements of patient care, including laboratory, radiology, dietary services, intravenous fluids, and use of specialty beds. It defined patient outcomes and outlined discharge planning. Pathways were distributed throughout all services caring for patients with pressure ulcers. Patient charts and billing data were reviewed for the 16-month periods before and after initiation of the pathway. No other significant changes in treatment occurred during this time frame. Ninety-seven patient charts were examined (54 before pathway and 43 after pathway implementation). Parameters evaluated included length of stay and total charges (including bed use, medications, laboratory tests, and radiology). Patient readmission rate was also examined. A significant reduction in patient length of stay and total charges was achieved after implementation of the clinical pathway. Reduction was seen not only for patients treated with flaps by plastic surgery but also for patients with pressure ulcers who were not specifically targeted such as those from other services. The readmission rate decreased slightly, although not significantly, after the pathway inception. Total cost saving was almost $11,000 per patient (23 percent). In conclusion, implementation of a clinical pathway, because it standardizes care and reduces variations and duplication of care, can reduce health care cost without impairing quality of care in the treatment of decubitus ulcer patients.

Use of postoperative information to predict mortality rates for patients who have long stays in the intensive care unit after coronary artery bypass grafting.

OBJECTIVE: To derive and evaluate prediction models for patients who had undergone coronary artery bypass grafting (CABG) and had a difficult postoperative course. DESIGN: Observational. SETTING: Midwestern hospital specializing in high-risk CABG procedures. PATIENTS: One hundred eighty-three patients who stayed at least 10 consecutive days in the intensive care unit after a CABG procedure. OUTCOME MEASURE: Death within 60 days of surgery. INTERVENTION: None. RESULTS: The final logistic regression prediction models included the following findings: pulmonary capillary wedge pressure, cardiac index, heart rate, urine output, positive end-expiratory pressure, blood urea nitrogen levels, and the arterial pressure of carbon dioxide. The model was able to stratify patients into four risk groups with observed 60-day mortality rates of 0.0% (n = 107), 21% (n = 39), 55% (n = 20), and 88% (n = 17). Preoperative patient information was not associated with prognosis for these patients. CONCLUSIONS: The findings suggest that a risk model that is specific for patients who have undergone CABG and is based on postoperative findings may provide useful prognostic information for patients who are having a difficult postoperative course.

Conference formats in family practice residencies.

BACKGROUND: This study was intended to establish national baseline data of the current structure of conferences at family practice residencies and to determine if there are differences in conference formats among types of residencies. METHODS: An author-developed survey was mailed to 331 programs stratified by type and randomly selected. Statistical analysis included chi-square tests and non-parametric tests. RESULTS: The response rate was 84%. The average time devoted to lectures was 4.5 hours a week, with the noon hour the most common time. Most speakers were from within the program, and community-based family physicians were rarely present. Structural changes were frequent. CONCLUSIONS: Results indicate that a variety of formats are implemented for meeting Residency Review Committee requirements in the structure of family practice residencies' conferences. Program settings do influence how conferences are structured. More research is needed on this neglected area of formal resident education.

Residents find clinical practice guidelines valuable as educational and clinical tools.

BACKGROUND AND OBJECTIVES: Information regarding clinical practice guideline (CPG) use in residency education is limited. We surveyed a regional population of family practice residents to determine use, attitudes, and curricular needs for practice guidelines. METHODS: A written survey was developed that measured residents' exposure to, frequency of use, attitudes, access, and knowledge about use of CPGs. The survey was mailed to 114 family practice residents. RESULTS: The response rate was 75%. The most frequently seen guidelines were immunization schedules, cancer screening, hyperlipidemia, and hypertension management. The residents reported positive attitudes toward CPGs; 75% thought CPGs were easy to use, 80% thought they improved their efficiency, 78% thought they improved their residency education, and 75% thought they improved patient care. Barriers to effective use of practice guidelines were also identified; 20% knew where to find guidelines in their clinic, 35% had faculty modeling, and 22% knew how to evaluate the validity of a guideline. Eighty-nine percent of respondents desired instruction on CPG use and interpretation. CONCLUSIONS: The surveyed family practice residents have similar usage rates for CPGs as the literature reports for practicing physicians, but residents report more positive attitudes. Barriers that prevent effective use of CPGs in training environments include lack of critical appraisal abilities and faculty role modeling.

Modeling the dynamics of adaptation to transgenic corn by western corn rootworm (Coleoptera: Chrysomelidae).

A simulation model of the population dynamics and genetics of the western corn rootworm, Diabrotica virgifera virgifera LeConte, was created for a landscape of corn, soybean, and other crops. Although the model was created to study a 2-locus problem for beetles having genes for resistance to both crop rotation and transgenic corn, during this first phase of the project, the model was simulated to evaluate only resistance management plans for transgenic corn. Allele expression in the rootworm and toxin dose in the corn plant were the two most important factors affecting resistance development. A dominant resistance allele allowed quick evolution of resistance to transgenic corn, whereas a recessive allele delayed resistance >99 yr. With high dosages of toxin and additive expression, the time required to reach 3% resistance allele frequency ranged from 13 to >99 yr. With additive expression, lower dosages permitted the resistant allele frequency to reach 3% in 2-9 yr with refuges occupying 5-30% of the land. The results were sensitive to delays in emergence by susceptible adults and configuration of the refuge (row strips versus blocks).