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PubMed2003

Comparison of cancer risk estimates based on a variety of risk assessment methodologies.

The EPA guidelines recommend a benchmark dose as a point of departure (PoD) for low-dose cancer risk assessment. Generally the PoD is the lower 95% confidence limit on the dose estimated to produce an extra lifetime cancer risk of 10% (LTD(10)). Due to the relatively narrow range of doses in two-year bioassays and the limited range of statistically significant tumor incidence rates, the estimate of the LTD(10) is constrained to a relatively narrow range of values. Because of this constraint, simple, quick estimates of the LTD(10) can be readily obtained for hundreds of rodent carcinogens from the Carcinogenic Potency Database (CPDB) of Gold et al. Three estimation procedures for LTD(10) are described, using increasing information from the CPDB: (A) based on only the maximum tolerated dose (the highest dose tested); (B) based on the TD(50); and (C) based on the TD(50) and its lower 99% confidence limit. As expected, results indicate overall similarity of the LTD(10) estimates and the value of using additional information. For Method (C) the estimator based on the [[(TD(50))(0.36) x (LoConf)(0.64)]/6.6] is generally similar to the estimator based on the one-hit model or multistage model LTD(10). This simple estimate of the LTD(10) is applicable for both linear and curved dose responses with high or low background tumor rates, and whether the confidence limits on the TD(50) are wide or tight. The EPA guidelines provide for a margin of exposure approach if data are sufficient to support a nonlinear dose-response. The reference dose for cancer for a nonlinear dose-response curve based on a 10,000-fold uncertainty (safety) factor from the LTD(10), i.e., the LTD(10)/10,000, is mathematically equivalent to the value for a linear extrapolation from the LTD(10) to the dose corresponding to a cancer risk of <10(-5) (LTD(10)/10,000). The cancer risk at <10(-5) obtained by using the q(1)(*) from the multistage model, is similar to LTD(10)/10,000. For a nonlinear case, an uncertainty factor of less than 10,000 is likely to be used, which would result in a higher (less stringent) acceptable exposure level.

Animals↗
PubMedDate not supplied

Visual performance requirements for post-PRK police recruits.

BACKGROUND: New Zealand Police regulations (1996) allow the unaided visual acuity requirement of 6/12 to be achieved following refractive surgery (except radial keratotomy or keratoplasty) provided applicants also achieve normal (95 per cent confidence limit data from the literature): glare disability, contrast sensitivity, and low luminance visual acuity, one year or more after treatment. METHODS: To confirm the limits adopted, 80 young normal adults were subjected to the tests in the regulations. To examine the operation of the current standards, the results of 34 post-photorefractive keratectomy (post-PRK) police applicants are reported. Glare disability was the loss of high contrast visual acuity (VA) with the Mentor Brightness Acuity Tester at medium intensity. Contrast sensitivity (CS) was examined using both Melbourne Edge Test thresholds and the VA difference between high and low contrast Bailey-Lovie charts. Low luminance VA was measured using high contrast Bailey-Lovie charts viewed through a one per cent transmittance filter. RESULTS: The 95 per cent confidence limits found for normal performance were as follows. Glare disability: no more than 10 letters worse than VA without glare. Contrast sensitivity: no more than 12 letters difference between high contrast and low contrast letter acuity together with an edge contrast threshold of not less than 20 dB (CS = 100). These results were close to the values adopted for the current standard. The 95 per cent confidence limit for low luminance VA was a loss of 24 letters (almost five lines) and not the three lines of loss estimated from the literature. Two of the 34 post-PRK applicants failed. One was unable to achieve 6/6 acuity with best refraction. The second could not meet the low luminance VA limit (loss no more than three lines). No failures have been due to glare disability or poor contrast sensitivity even though one applicant had obvious corneal haze.

Journal Article↗
PubMed1994

Aortic valve replacement with pulmonary homografts. Early experience.

The increasing use of the aortic homograft as aortic valve substitute and the limited availability of donor valves prompted us to consider the pulmonary homograft as an alternative substitute for aortic valve replacement. The aim of our study is to compare the ultrastructural and biomechanical properties of pulmonary homograft leaflets with those of their aortic counterpart and to present the early results of using the pulmonary homograft for aortic valve replacement. Light and transmission electron microscopy have shown that pulmonary homograft leaflets are thinner than the aortic with a lesser content of elastic tissue in the ventricularis layer. However there were no substantial differences in the ultrastructure. Uniaxial tensile tests were done on 69 cusps from human pulmonary and aortic valves using an Instron testing machine. The strain at 200 KPa was found to be similar for both pulmonary and aortic leaflets (8.20% +/- 2.87% versus 8.98% +/- 1.90%) cut circumferentially. Radial strips appear to be more extensible in pulmonary leaflets than in aortic (32.6% +/- 7.5% and 28.6% +/- 11.1%, respectively). The ultimate tensile strength for circumferential strips was found to be similar for both aortic and pulmonary valves (1460 +/- 857 kPa versus 1450 +/- 689 kPa), but there was relatively little difference between the radial strips (295 +/- 95 kPa versus 252 +/- 104 kPa). A total of 123 patients whose ages ranged between 13 and 78 years received either fresh antibiotic sterilized or cryopreserved pulmonary homografts for aortic valve replacement. The pulmonary homograft was inserted in place of the patient's diseased aortic valve by using one of two different techniques: freehand in the subcoronary position or as a "short cylinder" inside the aortic root. There was three hospital deaths (2.43%; 70% confidence limits = 1.08% to 4.83%). Cumulative follow-up was 184 patient-years (range 1 to 39 months). All surviving patients have been followed up with serial color flow Doppler echocardiography. There were no late deaths. Actuarial late survival was 97.5% (70% confidence limits = 95.7% to 98.6%) at 3 years. Four patients (2.2%/pt-yr) underwent reoperation because of severe aortic regurgitation (1, 4, 12, and 15 months after the operation) because of technical problems (mismatch in size between the pulmonary homograft and aortic anulus) in three patients and probably because of graft rejection in one patient. At 3 years the actuarial rate of freedom from reoperation was 95.5% (70% confidence limits = 92.7% to 97.3%). Mild aortic regurgitation has been detected in three patients (2.6%). No patients incurred thromboembolic episodes or infective endocarditis.(ABSTRACT TRUNCATED AT 400 WORDS)

Actuarial Analysis↗
PubMed1995

Alveolar lavage fluid (ALF) of normal volunteer subjects: cytologic, immunocytochemical, and biochemical reference values.

OBJECTIVE: Pooled bronchoalveolar lavage fluid (BALF), the return of lavage, contains both bronchial and alveolar material which differ from each other. Artifacts may be created by filtering, centrifuging and washing cells before cytopreparation. This study presents reference values of healthy volunteers for the alveolar sample, ALF, cytopreparation being performed without filtration or centrifugation. METHODS: Eighteen healthy, non-smoking volunteers underwent a standard bronchoalveolar lavage using 10 aliquots of 20 ml of saline. Excluding the return of the first and second aliquots, the rest were pooled and examined cytologically, immunocytochemically and biochemically. The mean, standard deviation, and 95% confidence limits were calculated for the following variables: amount of return, estimated content of epithelial lining fluid (ELF), total and differential cell counts on filter and cytocentrifuge (CCF) preparations, computed cell counts per unit volume of ALF, distribution of lymphocyte subgroups CD3+CD2, CD4, CD8, CD19, CD25 and CD57, and the ratio of CD4 to CD8, the amounts of lymphocytes in the same subgroups per volume of ALF, and the concentrations of total protein, albumin, immunoglobulins A, G and M, hyaluronic acid, eosinophilic cationic protein (ECP), procollagen III aminoterminal propeptide (PCP) and beta 2-microglobulin in ALF and in ELF, as well as the ratios of the concentrations of the solutes in ALF to the same in serum. RESULTS: The 95% confidence limits of means for the most important variables were as follows: estimated ELF content 0.42-0.74%; total cells in ALF 76.6-143.0 x 10(6) l-1; distribution of inflammatory cells on filter and CCF slides: macrophages 74.9-83.6 and 81.4-90.1%, lymphocytes 13.1-22.5 and 8.1-16.4%, and neutrophils 1.0-4.1 and 0.7-2.7%, respectively; distribution of lymphocyte subsets: CD3+CD2 85.6-90.6%, CD4 44.3-53.1%, CD8 26.9-35.8%; concentration of solutes in ALF: total protein 44.8-61.3 mg l-1, albumin 15.4-22.2 mg l-1, IgA 1.8-3.4 mg l-1, IgG 3.1-6.1 mg l-1, IgM 0.05-0.26 mg l-1, hyaluronic acid 8.8-11.1 micrograms l-1, ECP 0.19-0.77 micrograms l-1, PCP 0.005-0.58 micrograms l-1, beta 2-microglobulin 62.2-81.5 micrograms l-1. CONCLUSIONS: Our results show that excluding the bronchial sample from ALF of volunteer subjects and omitting filtering and washing before cytopreparation produces cytologic, immunocytochemical and biochemical reference values with reasonable 95% confidence limits to be used in clinical settings.

Adult↗
PubMed1988

Outcome of sterilization by steam autoclaves in Danish dental offices.

The aims of this study were to evaluate the performance of autoclaves and the use of biologic indicators for sterilization control, and to look for predictor variables for improperly functioning autoclaves in Danish dental offices. The study population comprised 314 Danish dental offices (participation rate 94%); 177 from the public Child Dental Service (CDS) and 137 from private practice. A minor questionnaire and five biologic indicators (Attest Biological Indicator for Steam Sterilization, 3M) were sent to the participants. CDS offices were found more inclined to use biologic indicators than PP offices (P less than 0.00001). Among CDS autoclaves 2.3% (95% confidence limit: 0.9-5.7%) failed to sterilize compared to 7.3% (95% confidence limit: 4.0-12.9) of the PP autoclaves. This difference is not statistically significant, but the confidence intervals indicate a possible true difference in favor of a better outcome in the CDS offices. Looking at the whole sample no other predictor variable for inadequate sterilization could be determined as differences were statistically insignificant with regard to years of professional experience, age and brand of autoclave, and use of biological control. Recommendations from an official body stating the approved types of sterilization control in dental offices would be of value.

Denmark↗
PubMed1995

Short-term mortality in childhood onset insulin-dependent diabetes mellitus: a high frequency of unexpected deaths in bed.

Mortality and the causes of death have been studied in a population-based cohort of 4919 childhood onset IDDM cases. Enrolment began in 1977 and at the time of study there had been a maximum duration of disease of 13.5 years, with a total of 33,721 person years at risk. Survival status was ascertained by linkage to the Swedish Cause-of-Death register. Death certificates, autopsy protocols, and hospital records were scrutinized for classification of causes of deaths. Twenty males and 13 females with IDDM died before the age of 28.5 years. This corresponds to a Standardized Mortality Rate for age of 262% (95% confidence limits, 172-400) for the boys and 384% (95% confidence limits, 232-635) for girls. Seven patients died of ketoacidosis, four at onset of diabetes. Nine cases were found 'dead in bed', having been seen apparently healthy 1-2 days before death. One of these cases had signs of cerebral haemorrhages at autopsy and another one had signs of bite marks in the mouth, but otherwise all autopsies were normal and no evidence of alcohol or other intoxication was found. In a well-educated population with good access to inexpensive diabetes care, there is still a two- to threefold excess mortality among young onset insulin-dependent diabetic individuals including a high frequency of unexplained deaths in bed.

Adolescent↗
PubMed1993

A randomized phase II trial of flutamide vs chlormadinone acetate in previously untreated advanced prostatic cancer. The Japan Flutamide Study Group.

We have conducted a double-blind comparative study of flutamide and chlormadinone acetate (CMA) on patients with stage C or D prostatic cancer and with no prior experience of hormone therapy. This is believed to be the first such trial entered in the medical literature, fifty-four patients were randomly selected to undergo flutamide (p.o.) monotherapy at a daily dose of 375 mg, which was determined as the optimal dose in Japan in our previous phase II study. Forty-nine others were randomly selected to undergo CMA (p.o.) monotherapy at a daily dose of 100 mg, which is the most commonly used dosage in Japan for patients with prostatic cancer. Ultimately, 47 patients from the flutamide group and 40 patients from the CMA group were judged eligible, with efficacy being evaluated after 12 weeks of treatment. Similar objective responses were seen in both groups: 48.9% (95% confidence limits 34.1-63.9%) in the flutamide group, 45% (95% confidence limits 29.3-61.5%) in the CMA group. The response at each organ site was also similar between the groups. Serum prostatic specific antigen decreased by more than 50% of the abnormal pretreatment level in 87.5% of the flutamide group and in 85.7% of the CMA group. Serum luteinizing hormone, follicle-stimulating hormone, testosterone and 5 alpha-dihydrotestosterone decreased significantly in the CMA group, but increased significantly in the flutamide group. The serum testosterone level after 12 weeks of treatment was 0.955 +/- 0.13 ng/ml in the CMA group and 6.64 +/- 0.38 ng/ml in the flutamide group. The serum estradiol level also increased significantly in patients in the flutamide group. The serum prolactin level decreased significantly in the flutamide group, but increased significantly in the CMA group. Eight patients on flutamide manifested gynecomastia. Diarrhea and hepatic toxicity were observed in both groups, but only rarely, and were well tolerated. We have thus concluded that flutamide is as effective as CMA in maintaining libido and potency without decreasing testosterone levels.

Aged↗
PubMed1994

Confidence intervals for weighted proportions.

We investigate methods for the construction of confidence intervals for a proportion in a stratified two-stage sampling design with few events occurring in a small number of large, unequal size strata. The critical aspect is the incorporation of the weighting scheme into the construction of a single overall confidence interval. With small numbers of events, the binomial based methods may be inadequate since the normal approximation is not valid. Computer simulations compare coverage probability and bias for five methods of obtaining confidence intervals for proportions by combining: (1) binomial variances; (2) confidence intervals based on the F-distribution approximation to the cumulative binomial; (3) the binomial variance method with exact confidence limits when a zero prevalence occurs in any stratum; (4) confidence intervals based on the F-distribution using a rescaling factor; and (5) the binomial variance method with exact confidence limits using a rescaling factor. The method that performs best in terms of coverage probability is the combination of stratum specific confidence intervals based on the F-distribution using a rescaling factor. The methods involving the binomial variance tend to be negatively biased and the methods based on the F-distribution tend to be positively biased. Application of these methods with data from a study of adolescent depression that employs a stratified two-stage sampling design is consistent with these results.

Adolescent↗
PubMed1980

Quantitative characterization of hormone receptors.

Most workers characterize steroid (and other hormone) receptors by graphical analysis of Scatchard plots or by simple linear regression. Unfortunately, these methods are suboptimal from a statistical point of view. The Scatchard plot, B/F vs. [Bound], does not satisfy the assumptions underlying simple linear regression: both variables are subject to error, and these errors are intimately interdependent. Accordingly, nether B/F nor [Bound] is an appropriate independent variable. Furthermore, both variables (B/F and [Bound] show non-uniformity of variance. Thus, even when the Scatchard plot is liner, one should estimate the binding parameters (affinity, K, and binding capacity, R) by means of weighted nonlinear least-squares regression, using the Total ligand concentration as the independent variable, and either B/T or [Bound] as the dependent variable. In the case of a nonlinear Scatchard plot, one should also use weighted nonlinear least-squares curve fitting to estimate the K and R values for the high and low affinity classes of sites. Allowing the computer program to provide the best estimate of the nonspecific or nonsaturable binding is also desirable. The program should provide estimates of the standard errors and/or 95% confidence limits for the estimated parameters, and the joint 95% confidence limits for K and R. One should routinely attempt to fit several models of varying degrees of complexity (e.g., 1,2, or 3 classes of sites), provide estimates of the goodness-of-fit for each, and then select the best model by statistical criteria. Sometimes, we encounter Scatchard plots that are obviously nonlinear but provide insufficient information within any one experiment to permit reliable characterization of two or more classes of sites. In this case, we may employ any of several alternative techniques, including 1) use of the " limiting slopes" technique to obtain approximate estimates of parameters; 2) use of a Continuous Affinity Distribution, with consideration of only the receptors with an affinity above an arbitrarily selected cutoff value of k; 3) use of a Discrete Affinity Distribution, by assigning values to the affinities (K19 K2) based on prior information, and then estimating the binding capacities; 4) pooling information over several specimens within an assay or over several assays by use of normalizing or scaling factors. The best estimates of these scaling factors can be obtained by the use of a general least-squares method for pooling data from different specimens or experiments. A series of computer programs to perform these analyses has been developed. They have been applied successfully to analysis of steroid receptors in specimens from breast carcinoma.

Breast Neoplasms↗
PubMed1989

The natural history of symptomatic haemorrhoids.

In order to calculate the prognosis for a person who has developed a first episode of second degree haemorrhoids, 186 patients were randomly assigned to either no active treatment (expectant management) (n = 91) or rubber band ligation (n = 98) and reviewed every 6 months. The median follow-up period was 48 months in both groups with a range from 6-48 months in the banding group and from 18-48 months in the expectant management group. Rubber band ligation was performed at most three times with three weekly intervals. There were 6 treatment failures in the banding group in contrast to 31 in the expectant management group (p less than 0.01). The calculated recurrence rate by actuarial analysis among patients initially cured by rubber band ligation was 33% (95% confidence limits: 23-45) at four years and 61% (95% confidence limits: 48-74) in the expectant management group (p less than 0.05). It is concluded that rubber band ligation of symptomatic second degree haemorrhoids in up to three single treatments at three weekly intervals at the time of diagnosis significantly altered the prognosis without causing significant morbidity. However, 25% of the patients treated by expectant management never developed another episode during the four years observation time.

Adult↗
PubMed1986

Hyperosmolarity as the stimulus to asthma induced by hyperventilation?

Hyperosmolarity of the epithelial fluid of the large airways caused by evaporative water loss (wloss) has been proposed as the stimulus to exercise-induced asthma. The aim of this study was to compare the wloss during hyperpnea with a theoretical wloss from a known hypertonic stimulus in order to determine whether comparable volumes of wloss will induce the same response. Since wloss also occurs during isocapnic hyperventilation (ISH), we decided to compare the airway response to ISH with the response obtained after inhaling 4.5% NaCl aerosol. Changes in FEV1 were measured in 17 subjects with asthma in response to increasing rates of ventilation (ISH) and increasing doses of 4.5% NaCl aerosol. For ISH, wloss was calculated at 29 mg/L of expired air and for 4.5% NaCl, at 4.0 ml/l ml of aerosol inhaled, as this is the volume of water that will bring the periciliary fluid to normal tonicity. Two dose-response curves were drawn for each subject. These curves were similar both in position (PD20) and in shape (i.e., the slope of the curve as estimated by the ratio of wloss for maximum recorded percent fall in FEV1 [PDmax] to PD20). There was no significant difference in the PD20 (ISH, 10.3 ml, 95% confidence limits 7.5 and 13.9; 4.5% NaCl, 12.3 ml, 95% confidence limits 8.9 and 17.1) or between the ratio of log PDmax:log PD20 (ISH, 1.19 +/- 1 SD, 0.14; 4.5% NaCl, 1.17 +/- 1 SD, 1.17; p = not significant). These findings support the concept that airway hyperosmolarity may be the mechanism for ISH and exercise-induced asthma.

Adolescent↗
PubMed1982

Risk factors for Kaposi's sarcoma in homosexual men.

An investigation of 20 homosexual men with histologically confirmed Kaposi's sarcoma and 40 controls revealed significant associations between Kaposi's sarcoma and use of a number of drugs (amyl nitrite, ethyl chloride, cocaine, phencyclidine, methaqualone, and amphetamine), history of mononucleosis, and sexual activity in the year before onset of the disease. Patients with Kaposi's sarcoma also reported substantially higher rates of sexually transmitted infections than did controls. Multivariate analysis indicated independent significant associations for amyl nitrite and sexual activity and showed use of phencyclidine, methaqualone, and ethyl chloride to be non-significant. Evaluated at the median exposure for patients, the analysis yielded risk-ratio estimates of 12.3 for amyl nitrite (95% confidence limits 4.2, 35.8) and 2.0 for sexual activity (95% confidence limits 1.3, 3.1).

Adult↗
PubMed1996

Natural history of infrainguinal vein bypass stenoses: early lesions increase the risk of thrombosis.

OBJECTIVES: To describe the natural history of stenoses in infrainguinal vein bypasses and to identify factors predicting outcome. METHODS: Forty-two patients with non-revised vein bypass stenoses were followed prospectively by ultrasound Duplex scanning and ankle blood pressure measurements. RESULTS: During a median follow-up of 8 (range 0-22) months 18 (43%) (95% confidence limits 28-59%) bypasses thrombosed and 6 (14%) (95% confidence limits 5-29%) patients were amputated. Bypass patency was lower in 12 patients with stenoses associated with reduction in ankle brachial index (ABI) exceeding 0.15 than in 30 patients with no or only marginal reduction in ABI (12 month patency 33% vs. 68%, p = 0.005). Among the 30 patients without distal pressure reduction, stenoses identified within 3 months from surgery were associated with an increased risk of thrombosis as compared to stenoses identified at a later stage (12 month patency 51% vs. 92%, p = 0.03). CONCLUSION: Time interval from surgery to stenosis detection seems to be an independent parameter influencing outcome in patients with vein bypass stenoses.

Aged↗
PubMed2000

Efficacy of pantoprazole in the prevention of peptic ulcers, induced by non-steroidal anti-inflammatory drugs: a prospective, placebo-controlled, double-blind, parallel-group study.

AIM: To evaluate the efficacy of pantoprazole in preventing gastrointestinal lesions in patients with rheumatic diseases receiving continuous, long-term treatment with non-steroidal anti-inflammatory drugs. MATERIAL: This was a prospective, randomised, double-blind, unbalanced, placebo-controlled, parallel group study. Outpatients (n= 104, age range 22-80 years, mean age 59.5) with rheumatoid arthritis or osteoarthritis, requiring chronic intake of NSAIDs (at least 8 weeks prior to the start of the study), were randomised and enrolled to receive either 40 mg pantoprazole (n=70) or placebo (n=34) once daily, for 12 weeks. Patients had endoscopically confirmed gastric and duodenal lesions grade 0, 1 or 2 (Lanza classification grade 0: normal to hyperaemic mucosa; grade 1: 1 to 3 erosions, submucosal haemorrhage or petechiae, grade 2: 4 to 10 erosions, submucosal haemorrhages or petechiae). Clinical and endoscopic evaluations were performed at baseline, after 4, and 12 weeks. The primary end-point of the study was the incidence of gastric or duodenal ulcers after 4 and 12 weeks of treatment. RESULTS: Patients (n=95) were evaluated: 65 in the pantoprazole group and 30 in the placebo group. When considering all patients (those with Lanza score grade 0, 1, 2 at baseline), the overall proportion of patients in remission was 82% and 77% after 4 weeks, and 72% and 59% after 12 weeks in pantoprazole and placebo groups, respectively (cumulative survival analysis according to Kaplan-Meier). The difference between the treatment groups was even more marked when only those patients with normal mucosa at baseline (grade 0) were considered. After 12 weeks, the proportion of patients in remission was 82% (95% confidence limits 70% - 94% in the pantoprazole and 55% (95% confidence limits 33% - 77%) in the placebo treatment group, p=O.036. Adverse events were reported in 4% and 6% of patients in pantoprazole and placebo treatment groups, respectively CONCLUSIONS: Pantoprazole 40 mg once daily was well tolerated and is more effective than placebo in the prevention of peptic ulcers in patients with rheumatic diseases who require continuous, long-term, treatment with NSAIDs.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1999

Audit of selected patients with nonfunctioning pituitary adenomas treated without irradiation - a follow-up study.

OBJECTIVE: Non-functioning pituitary adenomas (NFA) are the commonest type of pituitary macroadenoma. Although the initial definitive management of these tumours is almost always trans-sphenoidal surgery, the use of postoperative radiotherapy remains controversial. Radiotherapy has been shown to significantly reduce the risk of tumour regrowth. An audit of patients with NFAs treated with trans-sphenoidal surgery without irradiation was performed at our centre five years ago, and suggested that careful selection and follow-up could avoid the need for adjuvant radiotherapy. We have repeated this audit to assess the longer term effects of this management strategy. METHODS AND PATIENTS: The case notes and imaging of the original cohort of 65 of 73 patients (50 males, mean age 52) who had undergone trans-sphenoidal surgery (TSA) for NFA between July 1979 and 1992, had not received irradiation and were followed up by imaging were reviewed. Tumour regrowth was defined as enlargement of the pituitary tumour. Mean follow-up was 76 months (range 12-173). RESULTS: Pituitary tumour regrowth has occurred in 21 of the 65 patients (32%) during a mean follow-up of 76 months compared with 8/73 (11%) in 1994 (P = 0.002). The tumour regrowth was detected at a mean of 5.4 years (range 2-14 years). Lifetable analysis of the whole unirradiated group showed 82% recurrence free survival at 5 years (95% confidence limits 72-92%), and 56% at 10 years (95% confidence limits 38-74%). Eight (12%) patients required a second surgical procedure (6 TSA and 2 craniotomies). There was no relationship between recurrence and whether a total surgical removal was thought to have been performed. CONCLUSION: Despite careful selection of patients with non-functioning pituitary adenomas, tumour regrowth occurs in a significant proportion. These results show that continued follow-up in these patients is essential as significantly more patients showed evidence of tumour regrowth at this second assessment compared with the 1994 data. Until we are able to predict which tumours are likely to regrow postoperatively, radiotherapy should be considered for all patients with non-functioning pituitary adenomas as even in carefully selected cases, the regrowth rate is approaching 50% at 10 years.

Adenoma↗
PubMed2000

Nontransplant cardiac surgery for end-stage cardiomyopathy.

OBJECTIVE: To treat end-stage cardiomyopathy, we evaluated endoventricular circular patch plasty, partial left ventriculectomy, and valvular reconstruction alone in our 2-year experience. METHODS: Among 86 patients with heart failure evaluated between December 1996 and February 1999, 33 patients with ischemic cardiomyopathy (25 men and 8 women; mean age 61 +/- 7.8 years; New York Heart Association class 3.5 +/- 0.5) were treated with endoventricular circular patch plasty combined with coronary bypass grafting (84%) and mitral reconstruction (36%). The other 53 patients with nonischemic cardiomyopathy (45 men and 8 women; mean age 48 +/- 14.3 years, New York Heart Association class 3.7 +/- 0.5), were treated by left ventricular reduction by partial left ventriculectomy (n = 37) or patch plasty (n = 3) and valve reconstruction alone (n = 13). The first 24 patients (group I) underwent ventriculectomy with or without valve reconstruction; the more recent 29 patients (group II) underwent left ventricular reduction (n = 16) or valve reconstruction alone (n = 13) on the basis of the intraoperative echocardiographic evaluation to observe changes of wall motion and thickness during cardiopulmonary bypass. RESULTS: Ischemic Group: Hospital mortality in elective (n = 26) and emergency (n = 7) operations was 4% and 43%, and 3 patients died in the late postoperative period. Mean New York Heart Association class and ejection fraction improved from 3.5 +/- 0.5 to 1.5 +/- 0.7 and from 23% +/- 7.7% to 36% +/- 8.6%, respectively. Left ventricular end-diastolic and end-systolic volume indexes decreased from 162 +/- 46 mL/m(2) to 110 +/- 39 mL/m(2) and from 130 +/- 47 mL/m(2) to 70 +/- 32 mL/m(2), respectively. Nonischemic Group: In 40 patients with left ventricular reduction, hospital mortality in elective (n = 33) and emergency (n = 7) operations was 6% and 86%, and 5 patients died in the late postoperative period. Mean New York Heart Association class and ejection fraction improved from 3.7 +/- 0.5 to 1.7 +/- 0.6 and from 18% +/- 6.4% to 31% +/- 5.9%. Left ventricular end-diastolic and end-systolic volume indexes decreased from 203 +/- 45 mL/m(2) to 110 +/- 37 mL/m(2) and from 164 +/- 40 mL/m(2) to 79 +/- 33 mL/m(2), respectively. In 13 patients undergoing valve reconstruction alone (12 mitral with or without tricuspid and 1 tricuspid plus left ventricular assist device), hospital mortality in elective (n = 9) and emergency (n = 4) operations was 0% and 50% with no late deaths. Mean New York Heart Association class and ejection fraction improved from 3.6 +/- 0.5 to 2.0 +/- 0.5 and from 22% +/- 6.0% to 30% +/- 14.5%, respectively. Mean left ventricular end-diastolic and end-systolic volume indexes decreased from 170 +/- 34 mL/m(2) to 150 +/- 50 mL/m(2) and from 140 +/- 38 mL/m(2) to 104 +/- 40 mL/m(2), respectively. Overall mortality decreased from 50% in group I to 10% in group II. The survival estimates at 2 years were 77% (confidence limits 57%-88%) in the ischemic group and 63% (confidence limits 47%-75%) in the nonischemic group (no significant difference). The analysis of our data showed that the factors influencing the surgical results for dilated cardiomyopathy were presence of severe mitral regurgitation, preoperative New York Heart Association functional class IV with emergency operation, and operative procedures with randomly performed partial left ventriculectomy without an intraoperative echo test. CONCLUSION: Endoventricular circular patch plasty, partial left ventriculectomy, and solo valve reconstruction can be performed with an acceptably low risk as elective operations. The selection of operative procedures in idiopathic dilated cardiomyopathy and avoidance of emergency surgery improved operative mortality and morbidity. Among patients who survived at least 1 year, there were no late deaths up to 30 months' follow-up.

Adolescent↗
PubMed1995

Age-related effects in rabbit hearts of N6-R-phenylisopropyladenosine, an adenosine A1 receptor agonist.

Interventions known to increase cytoplasmic Ca2+ appear to amplify age-related impairment of cardiac function. In addition, increased release of interstitial adenosine, an endogenous nucleoside, has been suggested to mediate the diminished beta-adrenergic responsiveness in senescent heart. However, the direct effects of adenosine A1 receptor activation on senescent myocardium have not been investigated thoroughly. Therefore, the effects of N6-R-phenylisopropyladenosine (R-PIA), an A1 agonist, on atrial rate and contractility (+dF/dt) in adult (6-8 months) and senescent (5-7 years) New Zealand White rabbits were compared in spontaneously beating right atria and electrically stimulated isolated right papillary muscles. Although senescent right atria appeared to be more sensitive to the negative chronotropic-effects of R-PIA, the effective concentrations producing 50% of the maximum response (EC50 values) of R-PIA were not significantly different between adult (26 nM, 95% confidence limits: 12-52 nM) and senescent (13 nM; 95% confidence limits: 10-16 nM). However, senescent right ventricular papillary muscles were more sensitive to the negative inotropic effects of R-PIA. For example, at 90 contractions/min, 100 nM R-PIA decreased +dF/dt 25.3 +/- 7.4% and 61.9 +/- 4.8% in adult and senescent papillary muscles, respectively. To investigate whether R-PIA might alter sarcoplasmic reticulum (SR) function as a mechanism of decreased inotropy, we determined the inotropic effects of R-PIA on steady-state and 30-s postrest-potentiated contractions (PRP; an index of SR Ca2+ release) of left atria. R-PIA did not selectively decrease contractility of PRP compared to steady state in either adult or senescent left atria.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1986

Anaesthesia for colonoscopy. An examination of the anaesthesia as an element of risk at colonoscopy.

The importance of anaesthesia as an element of risk at colonoscopy has been examined retrospectively over a 10-year period from 1975 to 1984. The colonoscopic examinations were made by surgical gastroenterologists and anaesthesiologists working in cooperation. In 1242 cases the patients received diazepam/fentanyl anaesthesia during the colonoscopy (Group I) and in 126 cases they received general anaesthesia (Group II). The incidence of perforations of the large bowel in Group I was 0.8% (95% confidence limits: 0.4-1.5%) and in Group II 0.0% (95% confidence limits: 0.0-2.9%). Statistically the difference is not significant (P = 0.38). The groups were comparable with a view to the patients' age, weight, the duration of the colonoscopy and the number of times that polypectomy had been performed. All anaesthesia was administered by staff qualified by training and experience to administer anaesthesia, and did not cause any complications. However, four patients had vasovagal reflexes due to manipulation of the colonoscope. The dosing in the patients in Group I averaged: diazepam as premedication 9.2 mg, intravenous diazepam 12.4 mg, intravenous fentanyl 0.14 mg, and the duration of the colonoscopy was 36.5 min. The medication and the duration of the colonoscopy did not vary significantly in the patients with perforation of the large bowel. Our conclusion is that diazepam/fentanyl anaesthesia, administered by experienced staff, is harmless, and that general anaesthesia for colonoscopy did not involve an increased risk of perforation of the large bowel.

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