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PubMed1999

Evaluation of a training and diagnostic ultrasound service for general practitioners using narrowband ISDN.

We carried out a four-month pilot study of telemedicine for the delivery of training and diagnostic ultrasound services for general practitioners (GPs). Two health centres and a district general hospital were linked using ISDN (128 kbit/s) and PC-based videoconferencing units. Sixteen videoconferencing sessions were conducted, with 64 patients scanned over the ISDN link for a range of clinical conditions. Nine cases of pathology were demonstrated and confirmed by a consultant radiologist. A total of 229 images were transmitted using the store-and-forward facility, of which 194 (85%) images were of diagnostic quality and 35 (15%) were regarded as non-diagnostic. Allowing for sampling error, we would expect 79-89% of stored images to provide diagnostic information at a 95% confidence level. A total of 115 store-and-forward images (SAFI) were randomly selected and compared with hard-copy images (HCI) for technical quality. There was a significant difference in the quality of images. The results show that SAFI are far superior to HCI, traditionally used by clinicians for making primary diagnosis and that the superior quality of the SAFI improved diagnostic accuracy. This pilot study showed a high degree of confidence in videoconferencing for training GPs to carry out ultrasound clinics, enhancing their ability to make accurate diagnoses, and providing them with immediate access the second and higher opinion.

Education, Medical, Continuing↗
PubMed1988

Variability of the thymidine labeling index in squamous cell carcinoma of the head and neck.

Tritiated thymidine (3HTdR) labeling is the standard technique for determining the kinetic activity of tumors. This method has been used to label multiple sections of tumor specimens obtained from seven patients with advanced squamous cell carcinoma of the head and neck. Considerable variability was observed in the labeling index in different sites from the same specimen. To reduce the large sampling error due to heterogeneity, we recommend that an average value be determined from multiple sections when employing this technique.

Carcinoma, Squamous Cell↗
PubMed2004

Efficacy of cone biopsy of the uterine cervix during frozen section for the evaluation of cervical intraepithelial neoplasia grade 3.

We retrospectively selected 22 cases in which patients with a biopsy-proven diagnosis of cervical intraepithelial neoplasia grade 3 underwent cervical conization for frozen section (FS) evaluation followed by hysterectomy at the University of California Irvine Medical Center, Orange, during the August 1995 to September 9, 2001. All slides from FS and permanent section (PS) and hysterectomy specimens were reviewed. FS diagnoses were compared with those of previous biopsies, PS, and hysterectomy specimens. The PS correlated with FS in all cases but 1. Appropriate surgery was performed for all patients based on FS diagnosis. The McNemar test was used to compare the results of FS and PS, with a 2-sided P value of 1.0 and a c coefficient of 0.7755 with a 95% confidence level, indicating that the 2 groups were not significantly different. FS evaluation of cervical conization is as efficacious and accurate as evaluation of regular specimens in providing information for the appropriateness of same-day surgery. We recommend that entire tissue be submitted for FS to avoid sampling errors and to increase diagnostic accuracy.

Adult↗
PubMed2004

Calculation of the static in-flight telescope-detector response by deconvolution applied to point-spread function for the geostationary earth radiation budget experiment.

The Geostationary Earth Radiation Budget (GERB) experiment is a broadband satellite radiometer instrument program intended to resolve remaining uncertainties surrounding the effect of cloud radiative feedback on future climate change. By use of a custom-designed diffraction-aberration telescope model, the GERB detector spatial response is recovered by deconvolution applied to the ground calibration point-spread function (PSF) measurements. An ensemble of randomly generated white-noise test scenes, combined with the measured telescope transfer function results in the effect of noise on the deconvolution being significantly reduced. With the recovered detector response as a base, the same model is applied in construction of the predicted in-flight field-of-view response of each GERB pixel to both short- and long-wave Earth radiance. The results of this study can now be used to simulate and investigate the instantaneous sampling errors incurred by GERB. Also, the developed deconvolution method may be highly applicable in enhancing images or PSF data for any telescope system for which a wave-front error measurement is available.

Journal Article↗
PubMed1986

Effect of variation in manipulative force on the repetitiveness of centric relation registration: a computer-based study.

Measurement of the influence of the degree of applied force on the resulting retruded border position of the mandible established that the position varied significantly in all three dimensions according to variation in the amount of force. On the basis of the analysis of the t-test (sampling error of 8%), it can be concluded that increasing the manipulative force on the mandible in the general male population will result in a significant three-dimensional increase in the distance from centric occlusion to centric relation. The measurement data document the variability of the retruded centric relation position according to the different amounts of applied retrusive force. The data question the choice of the retruded border position on the basis of its clinical repetitiveness.

Adult↗
PubMed2026

Approaches to thyroid nodules in paediatric cancer predisposition syndromes.

OBJECTIVE: The objective of this work was to summarize current evidence and practical management considerations for thyroid nodules in children and adolescents with cancer predisposition syndromes (CPSs), focusing on follicular cell-derived nodules and non-medullary thyroid carcinoma (NMTC). METHODS: We synthesized current paediatric guideline recommendations and recent cohort, pathology, and molecular studies addressing CPS-associated nodular thyroid disease, including PTEN hamartoma tumour syndrome (PHTS), DICER1 syndrome, familial adenomatous polyposis, and related endocrine neoplasia syndromes. RESULTS: Evidence quantifying syndrome-stratified malignancy risk among paediatric CPS patients presenting with nodules remains limited and is largely derived from mixed-age or retrospectively ascertained cohorts with surveillance and verification bias. High-resolution ultrasound (US) is central to risk stratification. US-guided fine-needle aspiration (FNA) is a cornerstone of evaluation yet frequently yields indeterminate results, particularly in follicular-patterned and encapsulated lesions (e.g. PHTS and DICER1 syndrome), and sampling error is accentuated in polyclonal multinodular disease. Molecular testing may aid aetiologic clarification and, in selected settings, risk refinement. However, panels optimized for sporadic adult disease may have reduced 'rule-out' utility in CPSs. Biochemical assessment (TSH ± free thyroxine) complements imaging, while routine thyroglobulin is not recommended, and thyroid autoantibodies should be viewed as adjunctive rather than directive markers in CPSs. CONCLUSION: Management of thyroid nodules in paediatric CPSs is best approached through integrated, multidisciplinary risk assessment that combines expert ultrasound, context-aware cytology and molecular interpretation, and shared decision-making. This review proposes a CPS-adapted, multidisciplinary risk assessment framework and highlights the need for prospective multicentre registries and harmonized protocols to define syndrome-specific outcomes and evidence-based thresholds for surveillance and intervention.

Humans↗
PubMed2005

Is human immunodeficiency virus/acquired immunodeficiency syndrome decreasing among Brazilian injection drug users? Recent findings and how to interpret them.

We briefly review findings from Brazilian settings where the human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) epidemic among injection drug users (IDUs) seems to be decreasing, highlighting recent findings from Rio de Janeiro and discussing methodological alternatives. Former analyses using serologic testing algorithm for recent HIV seroconversion have shown that HIV incidence has been low in IDUs recruited by two different surveys carried out in Rio, where low injection frequencies and infection rates have been found among new injectors. The proportion of AIDS cases among IDUs in Rio has been fairly modest, compared to São Paulo and especially to the southernmost states. Notwithstanding, the interpretation of findings from serial surveys constitutes a challenge, magnified in the assessment of HIV spread among IDUs due to the dynamic nature of the drug scenes and limitations of sampling strategies targeting hard-to-reach populations. Assessment of epidemic trends may profit from the triangulation of data, but cannot avert biases associated with sampling errors. Efforts should be made to triangulate data from different sources, besides exploring specific studies from different perspectives. In an attempt to further assess the observed trends, we carried out original analyses using data from Brazilian AIDS databank.

Acquired Immunodeficiency Syndrome↗
PubMed2005

Long-term variability of zooplankton populations in aquatic mesocosms.

The natural variability on a spatial and temporal scale was examined in the zooplankton community of mesocosms from Syngenta Crop Protection AG (Stein, Switzerland), with the focus on improving the experimental design and evaluation of mesocosm studies. Analysis was performed using zooplankton data collected during a three-year period in 3 (1996 and 1998) to 12 (1997) ponds. Interreplicate variability was measured as the variance among the 3 to 12 replicates at each sampling date. Temporal variation was examined as seasonal variability by comparing different sampling dates within a year and as year-to-year variation by comparing pooled data year by year. Univariate and multivariate methods were used for the evaluation of population and community data, respectively. Results from the present study indicate that because of the low interreplicate variability, only data from high-abundance species could be evaluated with a precision able to detect effects less than 20%. For the majority of the zooplankton populations, abundances were lower than 10 organisms/L, with frequent zero counts resulting in a weak evaluation of the data with a precision able to detect effects of greater than 20 and 110%. Ordination analysis of the community data from the three years revealed that approximately 29% of the total variance could be explained by year-to-year differences, whereas 11% could be attributed to seasonal variability within a year. The residual variance can be attributed to interreplicate variability and sampling error. These results were in line with findings for individual populations. The present analysis demonstrated that the inherent variability of a system should be investigated for a proper design and evaluation of mesocosm studies and promotes the use of multivariate tools for a more comprehensive interpretation of mesocosm data.

Animals↗
PubMed1982

An independent analysis of the National Cancer Institute study on non-nutritive sweeteners and bladder cancer.

We evaluated the possible relation between use of non-nutritive sweeteners and bladder cancer using data obtained from the National Cancer Institute Bladder Cancer Study under the Freedom of Information Act. In the general study group, there was no evidence for an association between non-nutritive sweeteners and bladder cancer. Control for a variety of factors through multivariate techniques diminished the plausibility of earlier interpretations of these data, which had raised the possibility that certain subgroups of users or non-nutritive sweeteners might be at an increased risk for bladder cancer. We found that the putative effects of non-nutritive sweeteners were not consistent among subgroups with similar baseline risk, did not display consistent dose-response trends, and were subject to considerable sampling error. We concluded that the data provided little evidence that non-nutritive sweeteners increase risk for bladder cancer among subgroups of users, and that definitive evidence on this question is beyond the reach of conventional research.

Adult↗
PubMed1994

Adamantinoma of the long bones. A clinicopathological study of thirty-two patients with emphasis on histological subtype, precursor lesion, and biological behavior.

The records of thirty-two patients who had had an adamantinoma of the long bones were examined to investigate the relationship between the clinical presentation, the histological subtype, and the method of treatment, and the clinical result. All histological patterns of differentiation that are characteristic of adamantinoma were observed, including the basaloid, spindle-cell, tubular, squamous, and osteofibrous dysplasia-like subtypes. Follow-up data were available for twenty-eight (88 per cent) of the thirty-two patients. These patients were followed for a mean duration of 122 months (range, eleven months to twenty-nine years and two months). Nine patients (32 per cent), all of whom had been managed with an intralesional or marginal procedure, had a local recurrence of the tumor after a mean disease developed in three of the nine patients. In five other patients, metastasis developed without having been preceded by a local recurrence. Thus, the over-all rate of metastasis was 29 per cent (eight patients). The mean duration of survival for the patients who had metastasis was twelve years and eight months. Statistical analysis of various clinicopathological variables revealed intralesional or marginal excision to be the most significant risk factor for a local recurrence or metastasis (p < 0.001). Two patients who had had a presumed osteofibrous dysplasia-like adamantinoma, which contained few isolated keratin-positive epithelial cells within the stroma at the time of presentation, had a full-blown adamantinoma at the time of the local recurrence. Although the clinical course that was observed may be the result of a sampling error, it poses questions as to the regressive nature of osteofibrous dysplasia-like adamantinoma. On the basis of our findings and the data in the literature, we believe that an osteofibrous dysplasia-like adamantinoma may be a precursor lesion of the classic type of adamantinoma.

Adolescent↗
PubMed2006

Possible stimuli for strength and power adaptation: acute hormonal responses.

The endocrine system plays an important role in strength and power development by mediating the remodelling of muscle protein. Resistance training scheme design regulates muscle protein turnover by modifying the anabolic (testosterone, growth hormone) and catabolic (cortisol) responses to a workout. Although resistance exercise increases the concentrations of insulin-like growth factor 1 in blood following exercise, the effect of scheme design is less clear, most likely due to the different release mechanisms of this growth factor (liver vs muscle). Insulin is non-responsive to the exercise stimulus, but in the presence of appropriate nutritional intake, elevated blood insulin levels combined with resistance exercise promotes protein anabolism. Factors such as sex, age, training status and nutrition also impact upon the acute hormonal environment and, hence, the adaptive response to resistance training. However, gaps within research, as well as inconsistent findings, limit our understanding of the endocrine contribution to adaptation. Research interpretation is also difficult due to problems with experimental design (e.g. sampling errors) and various other issues (e.g. hormone rhythms, biological fluid examined). In addition to the hormonal responses to resistance exercise, the contribution of other acute training factors, particularly those relating to the mechanical stimulus (e.g. forces, work, time under tension) must also be appreciated. Enhancing our understanding in these areas would also improve the prescription of resistance training for stimulating strength and power adaptation.

Adult↗
PubMed1997

Constraints on antidepressant prescribing and principles of cost-effective antidepressant use. Part 2: Cost-effectiveness analyses.

Cost-effectiveness studies are a useful tool in drug-choice decisions. They are appropriate when alternative therapies have different levels of effectiveness, as with antidepressants. The calculation of cost effectiveness is similar to that used by some authors to determine whether a drug should be included in a formulary, so it clearly has immediate practical application and potential acceptability. However, the actual acceptability of cost-effectiveness studies has been hampered by a lack of conformity over study objectives, methodology and use of available data, and this significantly affects results. Studies that focus on the same location and setting, and conducted at the same time, frequently provide different results in their conclusions, depending on the assumptions and viewpoints, and the effects of sampling error. For example, dosage can affect purchase price calculations, but also compliance and efficacy, which are important considerations. Moreover, conclusions based on cost disadvantages of new drugs are not appropriate for planning for the future, since a drug's market price tends to fall with time and increasing demand. Appropriate use of outcome measures is important, and treatment failures, as well as successes, should be considered. Cost-effectiveness analysis has been used to demonstrate an important point: even when the appropriate use of antidepressants and specialty care increases medical costs, it improves value for money. A variety of drugs for one indication should be available to the prescriber, as the most cost-effective one may differ between patient subpopulations. Many costs of morbidity, adverse effects and secondary effects of antidepressants remain to be properly quantified, but are likely to have an important influence on cost effectiveness. These costs are likely to be higher for tricyclic antidepressants than the newer reversible inhibitors of monoamine oxidase and selective serotonin (5-hydroxytryptamine; 5-HT) reuptake inhibitors. Costing in some areas of health is relatively straightforward. Depression is among the most difficult areas to cost because of its gradation in severity, its chronic and recurrent nature, and its subtle effects on working capacity. Quantification of differences resulting from the use of different drugs has many pitfalls. Until now, each cost analysis of depression has differed from the last, and most have placed excessive reliance on poorly substantiated and hypothetical assumptions. More in-depth studies are required to define the most cost-effective policies for recommendation to healthcare decision-makers and antidepressant drug prescribers. Compliance, adverse effects, and safety in overdose are important factors. The impact of indirect costs also needs to be addressed.

Antidepressive Agents↗
PubMed2006

The organizing pneumonias : a critical review of current concepts and treatment.

In this comprehensive review, two very closely related interstitial pneumonias are discussed: the cryptogenic form of organizing pneumonia (COP); and secondary forms of organizing pneumonia (OP), which occur in association with identifiable medical conditions. Some newer and lesser known of these associated conditions are described, most importantly post-radiation OP.Rapidly progressive, corticosteroid-resistant and poor prognostic forms of OP have been described. These types purportedly occur more frequently in secondary OP. However, OPs frequently coexist with other interstitial pneumonias, especially when associated with connective tissue diseases. Therefore, tissue sampling error or an incorrect morphologic diagnosis can be the basis for the occurrence of clinically aggressive OPs. By using the 2002 American Thoracic Society/European Respiratory Society diagnostic criteria, some pre-2002 cases reported as OP would be re-classified today.Although COP is considered to have a good prognosis and to be corticosteroid responsive, approximately 70% of patients, treated with corticosteroids, relapse even during initial treatment. Multiple and late relapses occur in about one-third of the patients. We performed a meta-analysis of second-line treatment options for corticosteroid-refractory forms of OP. Three alternative nonsteroid agents - cyclophosphamide, azathioprine, and cyclosporin - have been used in combination with corticosteroids. On careful review, in a number of cases reported as secondary OP, other histologic interstitial patterns besides OP were described. The need for second-line therapy in these patients might have been dictated by the non-organizing pneumonic component. Most of the scant number of reports come from outside the US. World experience with these is limited, but good clinical outcomes have been noted, even in patients with interstitial patterns in addition to OP.The initiation of the OP tissue response in the bronchiolar and sub-bronchiolar location may be due to the presence of bronchiolar-associated lymphoid tissue found at the bifurcations of the bronchioles. Inhaled antigens stimulate granulocyte colony stimulating factor-mediated airway inflammation, followed later by CD44-mediated clearance. Repair requires intrabronchiolar formation of granulation tissue and a favorable ratio of matrix metalloproteinase to tissue inhibitors of metalloproteinase (MMP : TIMP) within the stroma. This reparative milieu allows extracellular matrix degradation and re-synthesis to occur. MMP-expressing fibroblasts then phagocytose the collagen fibrils and microfibrils produced earlier in repair, reversing the initial fibrosis.

Bronchioles↗
PubMed1980

Sonography of ventricular size and germinal matrix hemorrhage in premature infants.

Using the anterior fontanelle as an acoustic window, high resolution gray scale sonography brain scans with mobile apparatus were obtained in 35 premature infants. The sonographic technique provided accurate assessment of ventricular size and detected the subependymal germinal matrix and intraventricular hemorrhages. Ventricular size measurements correlated closely with computed tomography (CT) determinations (r = 0.83--0.92) in 29 infants. Sonography imaged the hemorrhages as areas of increased echogenicity with mass effect located characteristically in the region of the caudate nucleus. The size of the hemorrhages could be grossly estimated, but the full extent of hemorrhages was better delineated by CT. Sonography seemed superior in detecting small hemorrhages that were isodense with surrounding brain on CT. Despite its advantages of benignancy, accuracy, ease of examination, and cost, our sonography technique had limitations. False-negative sonograms occurred when the hemorrhage was located only in the posterior aspects of the ventricular system. Small hemorrhages in the caudate could be missed by either CT or sonography because of sampling error. Recognition of other disease processes was limited with sonography. The sonographic brain scan is a good initial test for high risk premature infants suspected of having subependymal germinal matrix and intraventricular hemorrhages. If the sonogram is negative or not typical for subependymal germinal matrix and intraventricular hemorrhages, CT is indicated.

Cerebral Hemorrhage↗
PubMed1985

CT-guided adrenal biopsy: accuracy, safety, and indications.

Fifty-eight percutaneous needle biopsies of adrenal masses were performed in 53 patients. The technique was initially successful in 44 (83%) of 53 patients. Five patients had second procedures because of initial failure or the possibility of sampling error. Fourteen biopsies were performed in nononcologic patients and 39 in patients with a known malignancy. None of the adrenal masses in nononcologic patients were malignant. Only 18 (46.1%) of the 39 masses in oncologic patients were metastases; the rest represented a variety of nonneoplastic conditions. Seven minor complications occurred in six patients. Two of these patients required transfusions for hypotension or decreases in hematocrit. No correlation was noted between needle size and complications. There were no pneumothoraces. The procedure is an accurate and safe alternative to surgical biopsy.

Adrenal Gland Diseases↗
PubMed1986

Fine-needle aspiration biopsy: pancreatic and biliary tumors.

Fine-needle aspiration biopsy was performed in 240 patients with suspected pancreatic or biliary tumors between 1978 and 1984. Between 1978 and 1982, using only sonographic guidance, the sensitivity of the technique was 66.7% for pancreatic and 40% for biliary tumors compared with 79.4% for carcinomas in other locations. The main reasons for failure to obtain positive cytology were small tumor size and sampling errors. From 1983 onward, combined sonographic and fluoroscopic biopsy guidance with opacification of the bile duct or pancreatic duct was routinely used together with heavier sedation to allow more careful needle placement. The sensitivity of the technique improved from 1983 to 1984 and was 77.5% for pancreatic tumors and 60% for biliary tumors. Failure of the cytologic technique to identify well-differentiated tumors and lymphomas has become a major source of tumor misdiagnosis.

Bile Duct Neoplasms↗
PubMed2006

Present state of and problems with core needle biopsy for non-palpable breast lesions.

The widespread use of screening mammography has resulted in increased detection of nonpalpable breast lesions here in Japan. For the histopathologic work-up of these lesions, stereotactic core biopsy is essential as a minimally invasive diagnostic procedure. However, the number of facilities that provide this procedure cannot keep up with the increasing demand from patients. Another issue is interpreting the results of the biopsy. With a histological diagnosis using needle samples, there is always a risk of underestimation or a false-negative result. To avoid missing cancers after stereotactic biopsy, it is important to check for sampling errors and for discrepancies between the radiologic and pathologic findings. We are pushing for the rapid spread of an ideal form of stereotactic breast core biopsy (using prone-type units, digital methods, and vacuum-assisted breast biopsy devices) throughout Japan so that every patient can undergo this examination.

Biopsy, Needle↗
PubMed1980

Reliability of seasonal variation in births of left-handed women.

Recently Leviton and Kilty reported that the birth dates of left-handed girls in elementary school display a seasonal trend which peaks in November. We report here a failure to replicate this finding for 257 male and 323 female college students. Further, we have considered the likelihood that the original finding was due to sampling error rather than speculating that environmental factors associated with the season of birth are implicated in the etiology of left-handedness, as Leviton and Kilty have stated.

Birth Rate↗