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Biomedical subjects

W Owen

Publications and source records attributed to W Owen.

At least 19 recordsLinked to original sources

Late referral and modality choice in end-stage renal disease.

BACKGROUND: We sought to determine whether late versus early referral to a nephrologist in patients with chronic kidney disease influences the initial choice of hemodialysis (HD) versus peritoneal dialysis (PD) or the likelihood of switching treatment modalities in the first six months of therapy. METHODS: Using New Jersey Medicare/Medicaid claims, all patients who started RRT between January 1991 and June 1996 and were diagnosed with renal disease more than one year prior to RRT were identified. In the resulting cohort of 3014 patients, 35% had their first nephrologist consultation < or =90 days prior to initiation of dialysis. RESULTS: After controlling for demographic characteristics, socioeconomic status and underlying renal disease, age, black race [Odds ratio (OR) = 0.56], race other than black or white (OR = 0.56), and socioeconomic status (OR = 0.68) influenced the choice of initial treatment modality, but timing of the referral did not. However, patients starting on PD who were referred late were 50% more likely to switch to HD than were patients who saw a nephrologist earlier [Hazard's ratio (HR) = 1.47]. In patients originally on HD, diabetic nephropathy (HR = 1.49) and black race (HR = 0.69) influenced the likelihood of switching to PD, but the timing of referral did not. CONCLUSIONS: These results refute earlier findings that late referral may limit access to PD. We found that modality choice depends on factors such as age, race, or socioeconomic status, rather than on than timing of nephrologist referral. Late referral does not influence the likelihood to switch modality in patients starting on HD, but does so in patients starting on PD.

Adult↗

Limitations of the facility-specific standardized mortality ratio for profiling health care quality in dialysis.

Health care quality is assessed by profiling measures of care and/or health outcomes. However, such tools to measure outcome as standardized mortality ratio (SMR) are often used without thorough validation of their strengths and limitations. Our study compared the dialysis facility-specific SMR and SMR-based rating using different statistical methods and followed them over time. All Fresenius Medical Care, North America dialysis facilities (n = 377) that contributed patient data from 1993 to 1995 (>103,500 patient-years) were included. Four distinct statistical methods (US Renal Data System [USRDS], Poisson, logistic, and Cox regression) were used to compute facility-specific SMRs and rank and classify facilities. The analysis compared the SMR and SMR-based rating of dialysis facilities between SMR method and over time. Different methods produced statistically significant differences in SMR distribution (P < 0.05). The USRDS method produced SMR values that decreased over time (P < 0.001). Based on 90% confidence intervals to determine outliers, the SMR-dependent ranking of dialysis facilities varied by method (P < 0.001). SMR-based ranking was stable over time except for the USRDS method (P < 0.001). Contingency table analysis showed up to a 33% total misclassification rate between SMR methods when ranking facilities. The facility-specific SMR and SMR-based ranking are both sensitive to statistical technique. Because the SMR yields different results in a year and over time and because there is no demonstrable gold standard, conclusions based on any one technique are unstable and unreliable. Regulatory monitoring, actions, and/or performance awards should be avoided based on this measure. However, a facility-specific SMR estimated in any valid way may be useful as an epidemiological research tool.

Adult↗

Cribriform variant papillary thyroid cancer: a characteristic of familial adenomatous polyposis.

Inherited cancer syndromes may predispose to more than one type of cancer, and these characteristically develop at an earlier age than their sporadic counterparts. The occurrence in a single individual of multiple, early onset primary cancers may indicate an inherited cancer susceptibility. Familial adenomatous polyposis (FAP), an autosomal, dominantly inherited susceptibility to colorectal adenomas and cancer also predisposes to childhood medulloblastomas and to a specific rare histologic type (cribriform variant) of papillary thyroid cancer. We describe a patient who developed a childhood medulloblastoma of the cerebellum, and subsequently a cribriform papillary thyroid cancer. These cancers predated the diagnosis of FAP in this patient, who was later found to have several relatives with FAP. The adenomatous polyposis coli (APC) mutation delineated in this family was in the region associated with those causing an increased risk of thyroid cancer. We submit that the diagnosis of the cribriform variant of papillary thyroid cancer in a young individual, especially after a previous cancer diagnosis, should alert the physician to the possibility of a diagnosis of FAP.

Adenocarcinoma, Papillary↗

The effects of capsaicin on reflux, gastric emptying and dyspepsia.

AIMS: To evaluate capsaicin's effects on heartburn, dyspepsia, gastric acidity and emptying, and gastro-oesophageal reflux, and to test the hypothesis that capsaicin induces heartburn and exacerbates symptoms by sensitizing the oesophagus. METHODS: Eleven heartburn sufferers underwent two separate pH monitoring sessions and assessments of gastric emptying (13C-octanoic acid breath test), heartburn and dyspepsia (100 mm VAS) after a non-irritant meal. The meal consisted of a sausage biscuit with egg, cheese and 30 g raw onion, 8 oz chocolate milk and a peppermint patty. Thirty minutes prior to meal consumption, subjects were administered a placebo capsule. On visit 1, subjects consumed the meal containing 100 microl 13C-octanoic acid cooked in the egg, over 15 min. On visit 2, subjects consumed the meal plus 5 mg capsaicin in gelatin capsules. RESULTS: Oesophageal and gastric pH profiles and gastric emptying were not different between meals. Capsaicin did not alter mean heartburn and dyspepsia scores (P > 0.05), but significantly decreased time to peak heartburn (120 min vs. 247 min; P < 0.003). Time to peak dyspepsia was not altered by capsaicin (P > 0.05). CONCLUSION: Capsaicin enhances noxious postprandial heartburn, presumably by direct effects on sensory neurons.

Adult↗

Arginine, citrulline, and nitric oxide metabolism in end-stage renal disease patients.

The kidneys are thought to be a major site of net de novo arginine synthesis, but the quantitative status of arginine metabolism and its substrate precursor relationship to nitric oxide (NO) synthesis in end stage renal disease (ESRD) patients have not been characterized. We have investigated kinetic aspects of whole body arginine metabolism in six patients with ESRD. They received two pre- and two post-hemodialysis intravenous tracer infusion studies with L-[guanidino-(15)N(2)]arginine and L-[(13)C]leucine during the first study, and L-[5-(13)C]arginine and L-[5-(13)C-ureido,5,5, (2)H(2)]citrulline during the second study. Arginine homeostasis in ESRD patients was found to be associated with a lower rate of arginine oxidation, and despite the decrease in renal function, the rate of de novo arginine synthesis appeared to be preserved. Plasma citrulline concentrations and flux were also elevated in these subjects compared with healthy adults. The rate of whole body NO synthesis was increased in the ESRD patients, but apparently not different pre- and post-hemodialysis therapy. The anatomic site(s) responsible for the maintenance of net de novo arginine synthesis and for the elevated NO synthesis and its pathophysiological importance in ESRD remain to be established.

Adult↗

The Oklahoma repair technique: a biomechanical study of a new suture repair technique.

We designed and evaluated the biomechanical advantages of a new (Oklahoma) suture technique for repairing flexor tendons in fresh, frozen cadaver specimens. Forty flexor digitorum profundi tendons from the middle three fingers were sharply cut and repaired with a number 3-0 braided polyester using the new technique and the Modified Kessler technique with and without an epitenon repair. The repaired tendons were then stressed to failure. The Modified Kessler with epitendon repair initiated gap formation on an average of 15.3 +/- 2.7 newtons and failed at 40.9 +/- 4.3 newtons. The Oklahoma suture technique with a running epitenon repair initiated gap formation on average of 48.6 (SD +/- 4.0) newtons and required an average load of 57.9 (SD +/- 3.0) newtons to fail. Thus, it was significantly stronger than the modified Kessler technique with epitendon repair (P < 0.01). The tendons repaired with the Oklahoma and epitenon repair suture technique did not form a 2 mm gap prior to failure. The epitendon repair increased the resistance to gap formation by 80% to 100% and the repair failure by 17.5% to 25% for both types of repairs. We concluded that the addition of the epitendon repair increases the tensile strength of the repair regardless of the core suture technique, and it should be used. In comparison with the Modified Kessler repair technique, the Oklahoma repair technique has superior tolerance to gap initiation, 2 mm gap formation, and physical failure of the repaired tendon.

Analysis of Variance↗

Association of acidosis and nutritional parameters in hemodialysis patients.

There is extensive literature supporting an important role for acidosis in inducing net protein breakdown, both in experimental animals and humans. However, the clinical importance of the moderate intermittent metabolic acidosis frequently observed in hemodialysis patients has not been determined. We performed a cross-sectional analysis of the baseline laboratory data in the first 1,000 patients recruited to the Hemodialysis Study, looking for correlations between predialysis serum total carbon dioxide levels and parameters related to dietary intake and nutritional status. We found the mean predialysis serum total carbon dioxide level was moderately low (21.6 +/- 3.4 mmol/L; mean +/- SD) despite the use of bicarbonate dialysate and an average single-pool Kt/V of 1.54. Predialysis serum total carbon dioxide level correlated negatively with normalized protein catabolic rate (P < 0.001), suggesting patients with lower serum total carbon dioxide levels have a greater protein intake. The degree of acidosis observed in our patients does not seem to have a deleterious effect on the nutritional status of these patients because correlation of serum total carbon dioxide level with nutritional parameters, such as serum creatinine and serum albumin levels, was either negative or not statistically significant. Further investigation of the effect of modifying serum bicarbonate concentration on nutritional markers is needed to test these hypotheses.

Acidosis↗

Effect of omeprazole in patients with chest pain and normal coronary anatomy: initial experience.

Gastroesophageal reflux is frequently found in patients with chest pain despite normal coronary anatomy, but little data on the effect of specific medication exist. After performing 24 h ambulatory pH monitoring and the Bernstein test on 23 patients with normal coronary anatomy, we gave omeprazole, 40 mg nocte, for six weeks to these and to a control group of ten patients with coronary disease. Pain episodes per fortnight fell from 16.2 to 12.0 (P=0.02) in the patients with normal anatomy and from 19.6 to 17.1 (nonsignificant) in the patients with coronary disease. Improvement occurred in seven (30%) of the patients with normal coronary anatomy compared with one (10%) of those with coronary disease, while complete resolution occurred in four (17%) and none, respectively. Improvement or complete resolution were not predicted by the results of 24 h pH monitoring, although there was a trend towards the prediction of efficacy by the Bernstein test. Omeprazole shows promise as a treatment for patients with chest pain despite normal coronary anatomy and larger placebo-controlled trials should now be undertaken.

Adult↗

Cubital tunnel release with medial epicondylectomy factors influencing the outcome.

From 347 cases of documented cubital tunnel syndrome, 160 required cubital tunnel release and medial epicondylectomy over a 10-year period and were considered for this retrospective study. These patients were monitored for 3 years after surgery. According to the modified scale of McGowan, 86% of patients were considered stage II. Eighty-one percent of the patients were symptom free, and 96% of the patients improved by 1 Wilson and Krout grade following surgery. We considered return of symptoms 3 months or longer after surgery as recurrence; there were 21 recurrences. There was no correlation between recurrence and limb dominance, patient age at the time of surgery, or length of preoperative conservative treatment. Of the patients with recurrences, 44% were in their fourth decade of life. The rate of recurrence in females (18%) was almost twice that in males (10%). The rate of recurrence was increased twofold when the patient did not return to work within 3 months. When concomitant ipsilateral carpal tunnel was present (44%), the recurrence rate was 17% compared with 9% in those without carpal tunnel syndrome. The recurrence rate was 20% when ipsilateral thoracic outlet syndrome was present compared with 9% in patients without other ipsilateral maladies. Therefore, higher recurrence rates should be anticipated in female patients, in patients with concomitant ipsilateral thoracic outlet syndrome and/or carpal tunnel syndrome, in patients in their third or fourth decade of life, or in patients not returning to work within 3 months after surgery.

Adolescent↗

Additional chemotherapy agents improve treatment outcome for children and adults with advanced B-cell lymphomas.

We report the updated results of an intensive treatment protocol for children (< 18 years) and adults (> or = 18 years) with advanced B-cell lymphomas. The protocol consists of two chemotherapy regimens: A, consisting of cyclophosphamide, doxorubicin, vincristine and high-dose methotrexate (CODOX-M), and B, consisting of ifosfamide, etoposide, and high-dose cytarabine (IVAC). Both cycles included intrathecal chemotherapy (cytarabine or methotrexate). Patients received a total of four cycles in the following sequence: A, B, A, B. Sixty-six previously untreated patients, enrolled before October 1996, were included in the present analysis. Of these, 55 had Burkitt's or Burkitt's-like lymphoma and 11 had diffuse large B-cell lymphoma. There were 53 males ad 13 females; 40 were children and 26 were adults (age range, 3 to 57 years). To date, 61 patients have achieved a complete response to therapy. Two patients subsequently relapsed, but one of these is a long-term survivor after further therapy and a bone marrow transplant. The event-free survival rate is 85% at I year and beyond. The median potential follow-up period is 48 months (range, 12 to 96 months) for patients remaining in complete remission. Neutropenia occurred in 98% of cycles and infection in 46% of A cycles and 50% of B cycles, but the duration was shortened in B cycles by the administration of granulocyte colony-stimulating factor. Positive blood cultures were observed in 21% of A cycles and 28% of B cycles, and there have been three toxic deaths. These results are better than those achieved with an earlier version of CODOX-M, suggesting that the addition of the IVAC regimen is responsible for the improved results. The similarity of the outcome in children and adults, however, confirms our previous observation that, at least in adults younger than 60 years with Burkitt's or Burkitt's-like lymphomas, treatment with regimens similar to those used in children is warranted.

Adolescent↗

Using uncovered metallic endoprostheses to treat recurrent benign esophageal strictures.

OBJECTIVE: The management of recurrent benign esophageal strictures is a difficult clinical problem, especially in patients who are not surgical candidates. We evaluated the role of uncovered metallic endoprostheses in four patients who had strictures that were resistant to repeated balloon dilatation. CONCLUSION: Our preliminary experience indicates that uncovered metallic endoprostheses can be effective in treating a select group of patients who have benign esophageal strictures and for whom multiple dilatations have failed. It is also important to note that epithelial hyperplasia can result in stenoses and recurrent dysphagia.

Aged↗

Hyperventilation and esophageal dysmotility in patients with noncardiac chest pain.

OBJECTIVES: Hyperventilation is known to cause esophageal spasm, but the importance of this interaction in clinical practice is unknown. In the present study, we report the effects of hyperventilation provocation on esophageal motility in a consecutive series of patients with noncardiac chest pain. METHODS: In a prospective observational study design, 46 consecutive patients with normal coronary angiograms were studied. Esophageal motility was recorded at rest and after voluntary over-breathing at 40 breaths/min for 3 min. RESULTS: Hyperventilation was associated with a significant fall in mean distal peristaltic amplitude [66 (SD 28) to 55 (SD 24) mm Hg, p <0.001] and mean duration [2.9 (SD 0.7) to 2.6 (SD 0.9) s,p = 0.02]. It induced diffuse spasm in two (4%) patients, and nonspecific motility disorders in 10 (22%). Chest pain was reproduced in seven (15%) patients, but in none did this coincide with an important change in peristaltic amplitude, duration, or frequency. CONCLUSION: Hyperventilation has important effects on esophageal motility, and manometrists should be aware of these before recommending that anxious patients overbreathe to help relaxation during clinical studies. Although overbreathing is a common source of dysmotility, it rarely produces chest pain via its effects on the esophagus.

Breath Tests↗

Smoking: high hazards in high school.

BACKGROUND: Young people in school are at an impressionable age, peer pressures are intense, and the probability that they will pick up a high-risk behavior, such as smoking, is high. The key to reduction of smoking among adults is to target our prevention efforts at young adults and teens. OBJECTIVE: To study the prevalence and trend of smoking among young adults and teens and to formulate guidelines on smoking reduction to guide those who counsel young people. STUDY DESIGN: The study design is cross sectional. METHODS: This study is based on the data from the Oklahoma Behavioral Risk Factor Surveillance System and the National Youth Risk Behavioral Surveillance System - the two systems that monitor the prevalence of behaviors that most influence health. RESULTS: The prevalence of smoking among young adults (age 18-24) in Oklahoma is high at more than 21%. The disturbing feature is that it is higher among young females than among young males. The prevalence of smoking among young adults is the highest among high school dropouts and is more than 38%. It is lower among high school graduates (about 28%) and lowest among college graduates (about 18%). The percentage of smoking among students who classify themselves as current smokers rises from 23% to 30% as the students progress from grade 9 to 12 and the percentage of frequent smokers increases from 8% to 16%. CONCLUSIONS: Guidelines suggested for counselors are: 1. Along with smoking, look for comorbid behaviors such as alcohol use, drug abuse, and high-risk sexual behavior. 2. Ask whether the student has easy access to free cigarette samples. 3. Check whether the teen is trying to lose weight; suggest appropriate methods for losing weight if smoking is being used for losing weight. 4. Target health education efforts early in a student's school career starting in elementary school, but concentrate especially at the 8th or 9th grade level to have maximum preventive impact.

Adolescent↗

Tolerability of combined ganciclovir and didanosine for the treatment of cytomegalovirus disease associated with AIDS.

Ganciclovir is one of only two drugs licensed by the U.S. Food and Drug Administration for the treatment of opportunistic cytomegalovirus (CMV) disease. The combination of ganciclovir and zidovudine has been reported to be poorly tolerated because of dose-limiting hematologic toxicity; thus we retrospectively examined the tolerability of combination therapy with ganciclovir and didanosine in 32 patients with AIDS. These patients were receiving ganciclovir for CMV disease in addition to didanosine in the Videx U.S. Expanded Access Program. During the period of combined therapy, dose-limiting hematologic toxicity (absolute neutrophil count, < 500 cells/microL) developed in only 9.4% of patients and severe anemia (hemoglobin level, < 8.0 g/dL) in only 12.5%. Rates of dose-limiting intolerance to didanosine were similar to those previously reported in the Expanded Access Program. Overall, 15 of 32 patients in the current study tolerated therapeutic doses of didanosine in combination with ganciclovir; in contrast, only 5 of 29 patients tolerated zidovudine (600 mg/d) in combination with ganciclovir in the largest trial of therapy with this combination whose results have been published to date (P = .02, Fisher's exact test). Since recent data suggest that the administration of some form of antiretroviral therapy prolongs survival in patients with CMV retinitis, coadministration of didanosine with ganciclovir should be considered for such patients who do not tolerate other regimens with activity against both retroviruses and CMV.

AIDS-Related Opportunistic Infections↗