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PubMed1993

Interobserver variability in histopathologic subtyping and grading of pulmonary adenocarcinoma.

BACKGROUND: The classification of lung tumors by the World Health Organization (WHO 1981) describes subtyping of adenocarcinoma of the lung (ACL) into acinar adenocarcinoma and papillary adenocarcinoma, bronchioloalveolar carcinoma, and solid carcinoma with mucus formation. Acinar and papillary adenocarcinoma may be graded as well-, moderately, or poorly differentiated. This study evaluated the interobserver variability in the subtyping and grading of ACL according to the WHO classification. METHODS: Histologic specimens from 211 patients with disease of Stages IIIa-IV were classified in a blind manner by three panelists. All available paraffin-embedded tissue blocks, including metastatic tumors, were sampled, and new slides were made for the study. RESULTS: Twenty-two ACL tumors could not be assigned a subtype by Panelist 1, which left 189 tumors as the basis for additional evaluation. Overall agreement for the three panelists regarding subtypes was 41%. Nonchance agreement was evaluated by kappa statistics, which may vary between -1 in the event of agreement that is less than that expected by chance and /1 in the event of full agreement. The kappa value regarding subtypes was 0.18 (95% confidence limits, 0.14-0.23). Overall observed agreement regarding degree of differentiation was 43%, with a kappa value of 0.12 (95% confidence limits, 0.06-0.17). Histologic material was obtained by thoracotomy in a subgroup of 53 patients, and in this patient group unanimity among two or more panelists was 88% for subtyping and 100% for degree of differentiation. CONCLUSIONS: The degree of agreement in subtying and grading of ACL in Stages IIIa-IV is low, suggesting that more objective criteria is needed before a prognostic impact of such variables can be assessed. The quality and quantity of material available for subtyping obviously influence the results, which is reflected in a better agreement when histologic material is obtained by thoracotomy.

Adenocarcinoma↗
PubMed1983

[Brain changes in parathion poisoning: observations in 42 cases].

A total of 42 cases were examined neuropathologically to determine possible toxic changes occurring in the brain after parathion intoxication. Sporadic anoxic alterations were observed in 7% of 41 cases in which the cause of death was acute intoxication. Nearly all cases (93%), however, showed marked hyperemia, often coupled with small reactionsless, periventricular hemorrhages which occurred in 40% of the cases. In one third of the cases (33%) there was moderate swelling of the oligodendroglia. Whereas histological evidence of edema was found in nearly one third of the cases (30%), comparison of the brain weights in these subjects with those of a large comparative collective showed definite pathologic brain weights in only five cases (12%) with 95% confidence limits. It is true that in 18 cases (42%) the brain weight was above the normal value if the confidence limit is ignored. Pronounced anoxic alterations were observed in only one case in which the individual survived the acute intoxication for 4 weeks after initial respiratory arrest. Predominantly toxic changes, however, could not be detected in any of the cases examined. This negative morphologic finding does not agree with the physiologic alterations reported by other investigators using animal models; they considered the cause of death in cases of parathion intoxication to be the result of toxic paralysis of the respiratory center. The literature was discussed.

Adolescent↗
PubMed2004

Intra- and interobserver variability of Kleerekoper's method in vertebral fracture assessment.

Radiographically detected vertebral fractures (VF) are a hallmark of osteoporosis. Several approaches to describe VF have been proposed. The objective of this study was to evaluate the intra- and interobserver variability of semiquantitative Kleerekoper's method in osteoporotic VF assessment. Sixty-seven postmenopausal osteoporotic (L2-4 T-score < or =-2.5) women with a mean age of 65.2+/-7.51 years were included into the study. Lateral radiographs of thoracic and lumbar spine were evaluated in all patients. Kleerekoper's method was used to define VF. Two observers evaluated all radiographs independently. To investigate intraobserver reproducibility, the first observer reevaluated all radiographs a month later on a separate occasion. Intra- and interobserver agreement was calculated using the kappa statistic. The agreement between two readings for the first observer was 86.3% with a corresponding kappa score of 0.573 (95% confidence limits of kappa score were 0.505-0.642). Interobserver agreement was 87.7% with a corresponding kappa score of 0.660 (95% confidence limits were 0.602-0.718). We observed a moderate agreement for Kleerekoper's method in vertebral fracture assessment. There is no gold standard or standardized measurement or description for VF. Quantitative assessment of VF is essential in epidemiologic studies and in clinical drug trials, but a semiquantitative technique, which is done by experienced observers, should also be added to evaluate the entire spectrum of visible features that are helpful in identifying deformities.

Absorptiometry, Photon↗
PubMed1998

Prevalence of the prothrombin 20210 G-to-A variant in blacks: infants, patients with venous thrombosis, patients with myocardial infarction, and control subjects.

A genetic variation in the prothrombin gene is located in the 3-untranslated region at position 20210 where a G-->A transition occurs. The prevalence of the mutation is 1% to 2% in white populations, and the mutation is associated with an increased risk of venous thrombosis and myocardial infarction. We report the prevalence of the A allele in blacks at birth; in black control subjects with no history of heart attack, stroke, or blood clots; in black patients with venous thrombosis; and in black patients with myocardial infarction. Among 318 infants, the prevalence of the A allele was 0.2% (1 heterozygote), with an exact, one-sided upper 95% confidence limit of 0.7%. Among 185 control subjects the variant was absent, yielding an exact, one-sided upper 95% confidence limit of 0.8% for the A allele. The heterozygous genotype was found in 2 of 91 subjects with deep vein thrombosis and in none of 123 subjects with myocardial infarction. The very low prevalence of the A allele indicates that the prothrombin variant is not a major cause of venous thrombosis or myocardial infarction in blacks.

3' Untranslated Regions↗
PubMed1987

A 7-year study of the diagnostic value of rectal mucosal acetylcholinesterase measurement in Hirschsprung's disease.

Over a 7-year period, 213 children were investigated for failure to pass meconium or for chronic constipation. Of these, 45 were confirmed to have Hirschsprung's disease; in this group the acetylcholinesterase activity in rectal biopsy tissue was significantly increased (P less than .001; mean 34.2, 95% confidence limits, 8.6 to 95.2) units g-1 when compared with the non-Hirschsprung's group (mean 6.6, 95% confidence limits, 2.0 to 15.9 units g-1). By expressing the acetylcholinesterase activity as a percentage of the total cholinesterase activity it is possible to compensate for evaporative weight loss and the combination of these two measurements improves the overall diagnostic value of the test. There were no false-positive and only two false-negative results.

Acetylcholinesterase↗
PubMed1985

Evaluation of coumatetralyl against two predominant murid species.

Coumatetralyl was evaluated in the laboratory against Bandicota bengalensis and Rattus rattus. Feeding tests with 0.0375% coumatetralyl baits produced 100% mortality after a single day feeding period in B. bengalensis and after a 10-day period in R. rattus. The anticoagulant bait is less palatable in comparison to plain bait. In the case of R. rattus, LFP50 and LFP98 and their 95% confidence limits were 3.89 (2.62-5.77) days and 11.22 (6.1-20.65) days respectively. Median period of survival and its 95% confidence limits of B. bengalensis and R. rattus were 4.7 (3.85-5.7) days and 11.2 (9.33-13.44) days respectively.

4-Hydroxycoumarins↗
PubMed1997

MyoD-E12 heterodimers and MyoD-MyoD homodimers are equally stable.

Muscle development is controlled by the MyoD family of basic helix-loop-helix (bHLH) DNA-binding proteins. These proteins dimerize with ubiquitous products of the E2A gene (E12 and E47) and bind in a sequence-specific manner to enhancer regions of muscle-specific genes activating their expression. In this study, fluorescence anisotropy has been utilized to characterize the interactions of recombinant MyoD and E12 in solution in the absence of DNA. The Gibb's free energies of dissociation (deltaG) and the equilibrium dissociation constants (K(D)) for the protein-protein interactions are reported. The deltaG for the MyoD homodimers in 100 mM KCl was 8.7 kcal/mol (K(D) = 340 nM), and increasing the salt concentration resulted in destabilization of the dimer. From titrations of MyoD-dansyl with E12 at 100 mM KCl, a free energy of heterodimerization of 8.7 (+0.4/-2.4) kcal/mol was recovered using rigorous confidence limit testing. The titrations of E12-dansyl with MyoD yielded a free energy of 8.3 kcal/mol with tighter confidence limits, +0.5/-0.8 kcal/mol. Thus, in the absence of DNA, both MyoD homodimers and MyoD-E12 heterodimers are relatively weak complexes of approximately the same stability. E12 does not form stable homo-oligomeric complexes; remaining monomeric at concentrations as high as 20 microM. Based on these results and the apparent binding constants reported previously for DNA binding, DNA is likely to facilitate the dimerization of MyoD and E12. Furthermore, higher affinity interactions of MyoD-E12 heterodimers versus MyoD homodimers with DNA binding sites is not due to preferential heterodimerization.

Animals↗
PubMed2000

Reticulocyte parameters as potential discriminators of recombinant human erythropoietin abuse in elite athletes.

This study investigated using reticulocyte (retic) parameters as indirect markers of human recombinant erythropoietin (r-HuEPO) abuse in elite athletes. Absolute reticulocyte count (# retic), the per cell haemoglobin content of reticulocytes (CHr), reticulocyte haemoglobin mass per litre of blood (RetHb) and red blood cell:reticulocyte haemoglobin (RBCHb:RetHb) ratio were assessed using flow cytometry. Venous blood was drawn from 155 elite athletes from six sports during regular training to establish reference ranges (95% confidence interval) for these parameters. The reference ranges were compared with those of a non-athletic population (n = 23), four groups of athletes (n = 24) before and after exposure to simulated altitudes (2,500-3,000 m for 11-23 nights), two groups of elite cyclists (n = 13) before and after four weeks of training at natural altitude (1,780 and 2,690 m), and with those of non-athletic subjects from a separate study (n =24) before and 1-2 days after they were injected with 1,200 U x kg(-1) r-HuEPO over a 9-10 day period. Generally the changes induced by r-HuEPO injection exceeded by approximately 100% the magnitude of the changes associated with natural altitude exposure. Simulated altitude exposure did not significantly alter the reticulocyte parameters. From the sample of 155 non-users and 24 r-HuEPO users, the population mean and variance, as well as the 95% confidence limits for the population mean and population variance, were estimated. Relative to arbitrarily chosen cut-off levels, the confidence limits for the rate of true positives and rate of true negatives were also calculated. Based on the lowest rate of false positives and highest rate of true positives, the best discriminator between r-HuEPO users and non-users was # retic, marginally superior to RBCHb: RetHb ratio and RetHb. At a cut-off for # retic of 221 x 10(9)x L(-1) we could be 95% sure that we would find no more than 7 false positives in every 100,000 tests. We would expect to pick up 51.8% of users, and could be 95% sure of picking up at least 38% of current or recent users. This result highlights the potential power of retic parameters for detecting r-HuEPO abuse among athletes. However, the efficacy of these cut-offs for detecting r-HuEPO abuse is unknown if an athlete is a chronic user or stops using r-HuEPO several weeks before being tested.

Bicycling↗
PubMed1996

Determining equivalence and the impact of sample size in anti-infective studies: a point to consider.

The problem of establishing the equivalence of an experimental treatment to a control with respect to a binary ("success" or "failure") response variable may be solved using an approximate (1-alpha) 100% confidence interval for the difference in the response rates (i.e., success probabilities). If the goal is to show that the experimental treatment is not sufficiently worse than the control, then a decision rule based on the magnitude of one confidence limit can be used. A procedure suggested by the Food and Drug Administration allows the value to which the confidence limit is to be compared to depend on the data. The consequences of determining the sample size assuming that the aforementioned value is fixed are examined. The probability of declaring equivalence and exact sample sizes are also presented for the procedure.

Anti-Infective Agents↗
PubMed1993

Quantitation of unintegrated HIV-1 DNA in asymptomatic patients in the presence or absence of antiretroviral therapy.

The objective of this work was to determine the amount of unintegrated human immunodeficiency virus (HIV) DNA (HIV uDNA) in asymptomatic individuals in the presence or absence of antiretroviral therapy. Twenty-one healthy seropositive individuals with no history of any opportunistic infection or previous use of nucleoside antiretrovirals, and 9 similarly asymptomatic individuals who had initiated nucleoside antiretroviral therapy within the last 24 months were studied. All patients had CD4 lymphocyte counts above 400/microliters. All subjects administered antiretrovirals received 400-600 mg of zidovudine daily for 2-24 months. Two individuals additionally received 400 mg of dideoxyinosine (ddI) daily for 4 and 5 months. Patient peripheral blood mononuclear cells (PBMCs) were examined for integrated and unintegrated HIV DNA by a quantitative PCR assay. In addition, CD4 counts were measured, and free and immune complex dissociated p24 antigen was detected in plasma by ELISA. The mean percentage of HIV uDNA in asymptomatic individuals not on therapy was 59%, with 95% confidence limits from 50 to 69%. In contrast, patients on therapy had a mean of only 13% HIV uDNA, with confidence limits from 2 to 25% (p < 0.001). These findings indicate that a significant amount of HIV DNA in infected, healthy patients not on therapy is in the unintegrated form, and that the amount of HIV uDNA in asymptomatic patients on nucleoside therapy is much less. The amount of HIV uDNA in PBMCs deserves further study as a new marker of the efficacy of antiretroviral therapy.

Adult↗
PubMed2003

Markers of the validity of reported energy intake.

Energy intake (EI) is the foundation of the diet, because all other nutrients must be provided within the quantity of food needed to fulfill the energy requirement. Thus if total EI is underestimated, it is probable that the intakes of other nutrients are also underestimated. Under conditions of weight stability, EI equals energy expenditure (EE). Because at the group level weight may be regarded as stable in the timescale of a dietary assessment, the validity of reported EI can be evaluated by comparing it with either measured EE or an estimate of the energy requirement of the population. This paper provides the first comprehensive review of studies in which EI was reported and EE was measured using the doubly labeled water technique. These conclusively demonstrate widespread bias to the underestimation of EI. Because energy requirements of populations or individuals can be conveniently expressed as multiples of the basal metabolic rate (BMR), EE:BMR, reported EI may also be expressed as EI:BMR for comparison. Values of EI:BMR falling below the 95% confidence limit of agreement between these two measures signify the presence of underreporting. A formula for calculating the lower 95% confidence limit was proposed by Goldberg et al. (the Goldberg cutoff). It has been used by numerous authors to identify individual underreporters in different dietary databases to explore the variables associated with underreporting. These studies are also comprehensively reviewed. They explore the characteristics of underreporters and the biases in estimating nutrient intake and in describing meal patterns associated with underreporting. This review also examines some of the problems for the interpretation of data introduced by underreporting and particularly by variable underreporting across subjects. Future directions for research are identified.

Adolescent↗
PubMed2002

Increased mortality in women with cataract: a population based follow up of the North London Eye Study.

BACKGROUND/AIMS: In diabetics, cataract is associated with higher risk of death. In non-diabetics the data are conflicting, but some indicate an association between one type of cataract (nuclear) and increased mortality. The aim of this study was to estimate and compare age and sex specific mortality for elderly people with and without cataract in a population based cohort. METHODS: A random sample drawn from a defined population of elderly people (age 65 and older) registered with 17 general practice groups in north London formed the study cohort and were followed up for 4 years. The age and sex specific mortality from various causes was estimated and compared in those with and without cataract. RESULTS: In non-diabetics (n=1318), cataract (lens opacity at baseline) was significantly associated with higher mortality in women. The age standardised death rate per 1000 was 39.8 and 24.8 in women with and without cataract, respectively (age adjusted hazard ratio 1.7, confidence limits 1.1 to 2.7, p=0.032). This was not the case in non-diabetic men (hazard ratio 0.9, confidence limits 0.6 to 1.5, p=0.782). The excess mortality in women with cataract was consistent for cardiovascular, respiratory, and other non-cancer causes of death. There was no association between cataract and mortality from cancer. CONCLUSIONS: This study has shown, for the first time, that cataract is associated with higher mortality in women but not in men, among the non-diabetic population. This sex effect suggests that women may be exposed to risk factors that increase both the risk of cataract and mortality, and that men may have little or no exposure to these "sex specific" factors. Possible risk factors that warrant further investigation may be those associated with some pregnancy and childbearing experience.

Age Distribution↗
PubMed2002

Acanthamoeba keratitis in England and Wales: incidence, outcome, and risk factors.

AIM: To determine the incidence, regional variation in frequency, outcome, and risk factors for acanthamoeba keratitis (AK) in England and Wales. METHODS: AK cases presenting from 1 October 1997 to 30 September 1999 were identified by the British Ophthalmic Surveillance Unit active reporting system. Clinical and patient postal questionnaire data were analysed. RESULTS: 106 reported cases met study criteria. The annual incidence for the 2 years was 1.26 and 1.13 per million adults and, for contact lens (CL) wearers, 21.14 and 17.53 per million. There was marked regional variation in incidence (0 to 85.13 per million adult CL wearers), with CL wearers in the south having a ninefold increased risk of AK compared with those resident in the north (95% confidence limits: 2.2-38.9, p<0.0001), and a threefold increased risk with hard as opposed to soft domestic water (95% confidence limits: 1.73 to 6.58, p<0.001). Treatment and outcome data were similar to those previously reported. 93/106 (88%) patients were CL wearers. Among these, 46/77 (60%) were disinfecting irregularly, and 20/63 (32%) had been swimming in CLs. One step hydrogen peroxide and chlorine release soft CL (SCL) disinfection systems were significantly over-represented among the cases. Among SCL users, one or more previously established risk factors for AK were identified in 50/55 (91%) patients. CONCLUSIONS: The incidence was considerably higher than most previous estimates, and was static. The geographical variation in incidence may be partly related to the increase in risk associated with hard water. The fact that water quality can have such an effect on the risk of AK suggests that many CL wearers must be letting tapwater come into contact with their lenses or storage cases. Improved education for CL wearers and practitioners about hygiene practice and the variable efficacy of contact lens systems could be expected to reduce the incidence of this disease.

Acanthamoeba Keratitis↗
PubMed1983

The relationship between pressure and flow in the normal pig renal pelvis. An experimental study of the range of normal pressures.

The renal pelvis pressure flow relationship of 40 normal pig upper urinary tract was investigated. During standardized studies it was disclosed that the resting pressure has a normal distribution with wide 95% confidence limits (0.3-14.7 cmH2O). When perfusion was introduced, pelvic pressure increased, the normal distribution was lost, and the 95% confidence limits were broadened to more than 30 cmH2O. A normal distribution was regained at higher flow rates. The mean increment beyond 8 ml/minute was small, only 3.7 cmH2O from 8 ml/minute to 20 ml/minute. The wide variation found in pressure responses to high flow rates and the spread of pressures at higher flow rates imply major difficulties in distinguishing, between normal and abnormal pressure flow relationships in renal pelvis.

Animals↗
PubMed1984

Pharmacologic and toxicologic profile of chymopapain B (Chemolase).

The median lethal dose (LD50) of chymopapain B in mice was 82 mg/kg (22,000 units/kg) with 95% confidence limits of 75-90 mg/kg (20, 122-24, 146 units/kg) and in rats 92 (24,683 units/kg) with 95% confidence limits of 83-102 mg/kg (22,268-27, 366 units/kg). The mechanism of toxicity was hemorrhage due to destruction of the cement substance of the blood vessels. Intervertebral disc injection of chymopapain B in the rabbit at a dose level of 186 micrograms (50 units) caused chemonucleolysis in 67% of the rabbits as evidenced by partial dissolution of the nucleus pulposus. Chemonucleolysis was also noted at higher doses. No adverse affects were noted with a 20 fold increase to 3.7 mg (1000 units). A dose of 18.6 mg (5000 units)/disc caused paralysis of the hindlegs. A dose as high as 26.6 mg (7143 units) /disc caused nearly complete dissolution of the nucleus pulposus and can cause disruption of the annulus fibrosus and death. Guinea pigs receiving a sensitizing dose of 0.003 mg/kg (0.8 units/kg) chymopapain B intraperitoneally six times over two weeks were challenged with an intravenous dose of 0.03 mg (8 units)/kg. All animals exhibited marked anaphylactic signs with a resulting 50% fatality rate.

Anaphylaxis↗
PubMed1983

Mortality from lung cancer in an acetylene and phthalic anhydride plant. A case-referent study.

Mortality from lung cancer in an acetylene and phthalic anhydride plant: A case-referent study. Scand j work environ health 9 (1983) 455-462. The study tested the hypothesis that an excess of lung cancer observed in a small town of the Milano Province in Italy was attributable to occupational exposures in a chemical plant (SISAS) producing mainly acetylene, phthalic anhydride, and their derivatives. Exposures included a large number of chemicals, some of which are known or suspected carcinogens such as soot and phthalates. The local register of deaths was the source of the cases and referents. The cases (N = 43) were the male residents in the town who had died from lung cancer from 1976 to 1979. The referents were a sample of residents from the same town who had died during the same four-year period from causes other than respiratory cancer. Causes of death were validated through clinical data and relatives' reports. Information for a complete occupational history and on smoking habits was collected in interviews of the next of kin of each study subject. After control for age and smoking, the risk of dying from lung cancer for the subjects previously employed at the SISAS plant relative to those never occupationally exposed was 5.6 (95% confidence limits 1.9-16.2). The risk for exposure to lung carcinogens in work environments other than SISAS was 1.7 (95% confidence limits 0.9-3.5). On the whole, occupational exposure to chemical carcinogens accounted for about one-third of the total number of lung cancer deaths that occurred in the area during the study period. The results call for further investigation of specific chemicals, mainly soot and phthalates, in the etiology of lung cancer.

Acetylene↗
PubMed1988

Increased risk of suicide in persons with AIDS.

The rate of suicide has been reported to be higher in persons with chronic and life-threatening illnesses (eg, cancer, Huntington's disease, and renal failure). We studied the rate of suicide in 1985 in New York City residents diagnosed with the acquired immunodeficiency syndrome (AIDS). There were 668 suicides in New York City residents in 1985, yielding a rate of 9.29 per 100,000 person-years. In men aged 20 to 59 years without a known diagnosis of AIDS, the rate was 18.75 per 100,000 person-years. There were 3828 individuals who lived with the diagnosis of AIDS for some part, or all, of 1985. There were 12 suicides in men aged 20 to 59 years from this group who lived 1763.25 person-years with a diagnosis of AIDS. This yields a suicide rate of 680.56 per 100,000 person-years. Thus, the relative risk of suicide in men with AIDS aged 20 to 59 years was 36.30 times (95% confidence limits, 20.45 to 64.42) that of men aged 20 to 59 years without this diagnosis, and 66.15 times (95% confidence limits, 37.38 to 117.06) that of the general population. We conclude that AIDS represents a significant risk factor for suicide.

Acquired Immunodeficiency Syndrome↗
PubMed1979

Scintigraphic and clinical evaluation of nontoxic thyroid neoplasms.

256 patients were referred to the endocrinic clinic because of enlarged thyroid gland. All of them except one were subjected to thyroid scintigraphy (TS). The scintiscans were cold in 123 patients. The cold scintiscans were distributed evenly on the various referral diagnoses with half the patients of each group having cold TS. A total of 216 of the referred patients underwent surgery, among them the 123 with cold TS. If the solitary adenomas are left out of account, there was poor agreement between referral diagnosis, primary tentative hospital diagnosis, and surgical findings. Five patients were found to have thyroid cancer (TC), none of whom had been referred with this diagnosis. For the entire material the incidence of TC was 2.3% (95% confidence limits: 0.8--5.7%). Calculated on the basis of those patients who had cold TS, the incidence was 2.4% (95% confidence limits: 0.8--7.1%). It is concluded that the diagnosis of TC is difficult to establish preoperatively, and that TS is of no greater diagnostic value in this connection.

Adenoma↗