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At least 793 records · Page 44Linked to original sources
PubMed1992

Role of the midgut gland in metabolism and excretion of ecdysteroids by lobsters, Homarus americanus.

The chromatographic profile of ecdysteroids (Ecds) from the midgut gland (MG) of juvenile female lobsters, Homarus americanus, was examined using high-performance liquid chromatography (HPLC) and radioimmunoassay (RIA) over four stages of the molt cycle. Upon initial examination, highly polar Ecd conjugates appeared to be the principal metabolites found in all molt stages. HPLC fractions containing apolar Ecds initially exhibited low RIA activity. Upon hydrolysis with a Helix pomatia enzyme preparation and reanalysis, significant amounts of other Ecds were released. Amounts of apolar Ecd conjugates were estimated, at their highest levels, to be at least 50% of the total Ecds in MGs of molt stage D3 lobsters. Only the MG formed significant amounts of apolar Ecds upon in vitro culture with [3H]ecdysone ([3H]E). Epidermis and antennal gland significantly increased their rates of [3H]E metabolism in vitro between molt stages C4 and D1. This result further supports the idea that regulation of ecdysteroid metabolism, at least in selected tissues, may be important in the molt cycle regulation of hormone titers. Using gel filtration column chromatography and sucrose density gradient centrifugation analyses, evidence was found for association of apolar Ecds with a protein(s) from MG cytosol. The protein was estimated to have a molecular weight of 180,000-200,000 and specifically bound apolar Ecds.

Animals↗
PubMed1987

Female axillary secretions influence women's menstrual cycles: a critique.

Preti, Cutler, Garcia, Huggins, and Lawley report (1986, Horm. Behav. 20, 474-482) that women's menstrual cycles can be modulated with applications of female-derived secretions. An experimental sample of 10 women who reported that they had 29.5 +/- 3 day menstrual cycles was treated on a 22- to 25-day cycle with an extract of axillary secretions from a group of female donors. After two menstrual cycles, the mean absolute difference between the women's menses onsets and the treatment applications decreased significantly. A control sample of 9 women similarly treated with blank/ethanol showed no significant change. Reanalysis of the data indicates that four subjects in the extract sample synchronized with the extract cycles because of "errors" in the extract applications and another four synchronized as a result of experimental design, mathematical properties of cocycling menses onsets, and chance variations. After these factors are accounted for, no evidence suggests that the cycles of the subjects in the extract sample were modulated by the female-derived axillary secretion.

Axilla↗
PubMed1984

Design sensitivity analysis: a new method for implant design and a comparison with parametric finite element analysis.

A unified theory of structural design sensitivity is proposed to be used in conjunction with the parametric design variation method traditionally used in finite element analyses applied to biomechanics problems. Bone cement strain energy density dependence on cement and stem modulii of elasticity as analyzed with the theory of structural design sensitivity analysis is compared parametrically varied finite element results. Two-dimensional, eight-noded isoparametric and interface finite elements with optimal stresses at Gauss points are employed. Design sensitivity for strain energy density compares well with perturbation of design and reanalysis by finite element techniques.

Hip Prosthesis↗
PubMed1984

A nonlinear analysis of phonological disability.

In the spirit of Gandour (1981) a reanalysis is presented of the speech of a 6-yr-old language delayed child, Rosey, whose phonologic disorder has been discussed by Grunwell (1982). A revealing account of the data can be given by adopting a nonlinear framework; specifically, recent amendments to Goldsmith's (1976) theory of autosegmental phonology. This analysis borrows from autosegmental accounts of Arabic morphology, reduplication, and Kikuyu tone shift (all of which are briefly described). The processes postulated to explain the "deviant" pattern of data, hence, are all well motivated from the grammars of other languages. The analysis is contrasted with a "classical" (SPE) generative analysis and, thus, provides indirect evidence in favor of autosegmental theory over the classical theory. At the same time, the position of such phonologic analyses in psycholinguistic models of acquisition is briefly discussed.

Child, Preschool↗
PubMed1983

Effects of marijuana on testosterone in male subjects.

Clinical studies have given contradictory reports on the effect of smoking marijuana on the plasma levels of testosterone in males. A reanalysis of existing data established that testosterone levels are depressed both after smoking one marijuana cigarette and after intravenous infusion of delta-9-tetrahydrocannabinol, a pharmacologically active component of marijuana. Simulation of the marijuana interaction, under the assumption that delta-9-tetrahydrocannabinol inhibits testosterone production or secretion, suggests a minimum of 24 hours are required for testosterone to return to pre-smoking levels. A series of clinical studies are specified to clarify the nature of the interaction.

Cannabis↗
PubMed1996

A biologically based model for the analysis of premalignant foci of arbitrary shape.

In many animal carcinogenesis experiments, quantitative data on putative premalignant foci are now routinely collected. Moolgavkar et al. [Carcinogenesis 11:1271 (1990)] considered the analysis of such data from a rat hepatocarcinogenesis experiment within the framework of a two-stage model for carcinogenesis using the assumption that the premalignant clones were spherical. This assumption seems questionable in many organs, including the liver. In this paper, it is relaxed and arbitrary shapes are allowed for the clones. The proposed method is illustrated by reanalysis of the data considered in the earlier paper. The new analysis yields parameter estimates that are more plausible biologically than those of the original analysis.

Animals↗
PubMed1988

Increased somatic cell mutant frequency in atomic bomb survivors.

Frequencies of mutant T-cells in peripheral blood, which are deficient in hypoxanthine guanine phosphoribosyltransferase (HPRT) activity, were determined for atomic bomb survivors by direct clonal assay using a previously reported method (Hakoda et al., 1987). Results from 30 exposed survivors (more than 1 rad exposed) and 17 age- and sex-matched controls (less than 1 rad exposed) were analyzed. The mean mutant frequency (Mf) in the exposed (5.2 X 10(-6); range 0.8-14.4 X 10(-6)) was significantly higher than in controls (3.4 X 10(-6); range 1.3-9.3 X 10(-6)), which was not attributable to a difference in non-mutant cell-cloning efficiencies between the 2 groups, which were virtually identical. An initial analysis of the data did not reveal a significant correlation between individual Mfs and individual radiation dose estimates when the latter were defined by the original, tentative estimates (T65D), even though there was a significant positive correlation of Mfs with individual frequency of lymphocytes bearing chromosome aberrations. However, reanalysis using the newer revised individual dose estimates (DS86) for 27 exposed survivors and 17 controls did reveal a significant but shallow positive correlation between T-cell Mf values and individual exposure doses. These results indicate that HPRT mutation in vivo in human T-cells could be detected in these survivors 40 years after the presumed mutational event.

Aged↗
PubMed1987

An alternative to interference indexes in neuropsychological time-sharing research.

Interference indexes are used as criterion measures in a significant proportion of time-sharing paradigms in order to control for the initial discrepancy between left- and right-handed tapping rates. Problems associated with these indexes include low reliability, low statistical power, and especially correlations with baseline tapping rates. An analysis of covariance procedure using raw-score concurrent tapping rates as criterion measures, and baseline tapping rates as covariates, can effectively address these problems as demonstrated through a reanalysis of data.

Functional Laterality↗
PubMed1984

On the directionality of classically-conditioned glycemic responses.

Rats were administered either exogenous insulin or glucose as the unconditioned stimulus paired with a distinctive stimulus complex. Following several such pairings, the administration of a saline (test) solution to the animal in that environment produced, in both cases, a reduction in blood-glucose levels (hypoglycemia) as compared to control animals who received saline injections throughout. We suggest that, contrary to previous researchers' assumptions, direct changes in blood glucose levels immediately following the administration of either glucose or insulin should not be treated as the unconditioned response. The response of the CNS to the glucose or insulin, and not the immediate effect of increases or decreases in blood glucose levels, must be considered. Our reanalysis suggests, then, that in the case of glucose conditioning the conditioned response produces hypoglycemia which is in the same direction as that of the unconditioned response. In the case of insulin conditioning, the unconditioned response has not been well identified and consequently the conditioned response may be in the same or opposite direction to that of the UR.

Animals↗
PubMed1991

Aggression by a female rat cohabitating with a sterile male: termination of pseudopregnancy does not abolish aggression.

At the end of that time, each female was assessed for aggressiveness toward an unfamiliar female intruder once each week for 3 weeks. Those females displaying a high level of aggression had their male cagemate changed. For half of the females, the new male cagemate was a castrated male with a testosterone implant. For the other half, the new cagemate was a castrated male without a testosterone implant. Replacement males had been subjected to surgery 9 weeks previously. There were no differences in the aggressiveness of females of the two groups on any of 3 subsequent weekly tests of aggression. In a 3-h evaluation of male sexual behavior, none of the 9 castrated males without testosterone replacement displayed sexual activity with an estrogen/progesterone primed ovariectomized female, but 6 of 9 males with testosterone replacement did. Reanalysis of the aggression data comparing the females whose males had no testosterone replacement and females housed with the 6 males that were sexually active also revealed no differences in aggression over the 21-day test period. Since pseudopregnancy is known to last 13 days, these results indicate that the continuous presence of pseudopregnancy is not required for maintenance of aggression by a female cohabiting with a sterile male.

Aggression↗
PubMed1992

Sequence and transcript analysis of the bovine herpesvirus 1 thymidine kinase locus.

A detailed sequence and transcript analysis of the thymidine kinase (tk) gene of bovine herpesvirus 1 (BHV1, Cooper strain) was carried out. A tk open reading frame (ORF) of 1077 bp was identified and compared with tk ORFs previously published for other strains of BHV1. The Cooper sequence was in good agreement with that of strain Q3932 but differed significantly from strains 6660 and LA. Reanalysis of the LA tk sequence, however, failed to confirm this difference. Except for five single base substitutions, our results indicate that the Cooper, Q3932, and LA strains share the same tk sequence. The size of the tk mRNA was determined by Northern blot analysis. In contrast to the size of other herpesvirus tk mRNAs (approximately 1.5 kb), the BHV1 tk transcript was 4.3 kb. Northern blot analysis indicated that the tk transcript was 3' coterminal with the downstream 3.1-kb transcript which encodes a BHV1 homologue of the HSV1 H glycoprotein (gH). The 5' ends of the tk and gH mRNAs were mapped by S1 analysis to positions 135 and 91 bp upstream of their respective translation start sites. The 5' end of the tk transcript was found to overlap a 5.2-kb transcript with opposite polarity to the tk mRNA.

Base Sequence↗
PubMed1986

Higher order color mechanisms.

Evidence supporting the existence of higher order color mechanisms, that is, ones beyond the previously identified second stage mechanisms is presented. This evidence includes a reanalysis of the data of Krauskopf et al. [Vision Res. 20, 1123-1131 (1982)] on the desensitizing effects of viewing chromatically modulated fields, new experiments on a generalized version of the "transient tritanopia" experiment of Mollon and Polden [Phil. Trans. R. Soc. Lond. 278, 207-240 (1977)] and results on the relationship between discrimination and detection of brief color changes.

Animals↗
PubMed1988

Circadian and circannual rhythms of allergic rhinitis: an epidemiologic study involving chronobiologic methods.

Seven hundred sixty-five patients, living in France and suffering from allergic rhinitis (eg, with positive skin tests to various antigens), agreed to self-rate (visual analog scales), four times daily, symptoms such as sneezing, stuffy or blocked nose, runny nose, itchy nose, itchy eyes, wheeze, or cough. Despite acute symptoms, patients did not take medications of any kind by any route during 36 hours. Several statistical methods (eg, Student's t test, analysis of variance, cosinor, chi-square, etc.) were used to validate both circadian and circannual rhythms of these symptoms in the group as a whole, as well as in subgroups related to age, sex, etc. Large-amplitude circadian rhythms with early morning peak times (eg, approximately 6 AM) were validated for sneezing, stuffy nose, and runny nose (with p less than 0.0001) but not for wheeze or cough. Such time-dependent changes were related neither to age (from 10 to 80 years) nor to sex. However, small differences were observed in subgroups sorted with regard to duration of disease (old versus new cases), smoking habits, and geographic location (north versus south France). Reanalysis of data taking into account interindividual differences revealed that the respective peak times of the three major symptoms occurred in the early morning in about 60% to 70% of the patients. Annual changes were validated as well with the annual peak time being January to April. The proposed interpretation of both circadian and circannual rhythms suggests taking into account endogenous component rhythms (eg, involving metabolic, immunologic, and endocrine systems), since they contribute to time-dependent changes in the human susceptibility to antigens. In addition, the elevated severity of symptoms in the morning experienced by 60% to 70% of patients should serve as a guide to individually optimize dosing time(s) of medications, such as antihistamines.

Age Factors↗
PubMed1984

An evaluation of the intervention against smoking in the multiple risk factor intervention trial.

The results of the Multiple Risk Factor Intervention Trial showed no significant difference in mortality from coronary heart disease between intervention and control groups despite an apparent success of the intervention against cigarette smoking. A reanalysis of the published data indicates that the effectiveness of the smoking intervention may have been overestimated. The researchers counted those who smoked pipes or cigars at screen as nonsmokers and attempted to classify cigarette smokers who switched to pipes or cigars during the trial as successes whether or not they continued to inhale the smoke. It is unreasonable to assume a priori that inhaling pipe or cigar smoke is less dangerous than cigarette smoke. Moreover, attempting to include pipe and cigar smokers, who may have been inhaling smoke, among the successes makes biochemical validation of claims of abstinence overly lenient. When levels of serum thiocyanate are used to obtain an objective index of smoking reduction, it appears that the effect of intervention was considerably smaller than has been reported, and failed to reach design goals over the first 4 years. This could help to explain the disappointing mortality results.

Carbon Monoxide↗
PubMed1991

Estrogen replacement therapy and coronary heart disease: a quantitative assessment of the epidemiologic evidence.

Considerable epidemiological evidence has accumulated regarding the effect of postmenopausal estrogens on coronary heart disease risk. Five hospital-based case-control studies yielded inconsistent but generally null results; however, these are difficult to interpret due to the problems in selecting appropriate controls. Six population-based case-control studies found decreased relative risks among estrogen users, though only 1 was statistically significant. Three cross-sectional studies of women with or without stenosis on coronary angiography each showed markedly less atherosclerosis among estrogen users. Of 16 prospective studies, 15 found decreased relative risks, in most instances, statistically significant. The Framingham study alone observed an elevated risk, which was not statistically significant when angina was omitted. A reanalysis of the data showed a nonsignificant protective effect among younger women and a nonsignificant increase in risk among older women. Overall, the bulk of the evidence strongly supports a protective effect of estrogens that is unlikely to be explained by confounding factors. This benefit is consistent with the effect of estrogens on lipoprotein subfractions (decreasing low-density lipoprotein levels and elevating high-density lipoprotein levels). A quantitative overview of all studies taken together yielded a relative risk of 0.56 (95% confidence interval 0.50-0.61), and taking only the internally controlled prospective and angiographic studies, the relative risk was 0.50 (95% confidence interval 0.43-0.56).

Adult↗
PubMed1987

More things in heaven and earth than are dreamt of in the initial letter acuity hypothesis.

Schwartz, Montagner, and Kirsner (1987 Brain and Language, 31, 301-307) claim that length X visual hemifield interactions for recognition of horizontal words reflect acuity differences for the initial letters of short and long words rather than different methods of lexical access for words presented in the LVF and in the RVF. They argue that Young and Ellis did not satisfactorily eliminate this possibility because they (Young & Ellis, 1985, Brain and Language, 24, 326-358, Experiment 3) allowed the use of sophisticated guessing strategies. We demonstrate that the presentation conditions of the Schwartz et al. (1987) experiment are different from those of our (Young & Ellis, 1985) experiments in potentially important ways, and that the acuity gradient explanation proposed by Schwartz et al. to account for word length X visual hemifield interactions is inadequate in terms of both the existing literature and a reanalysis of data from our own (Young & Ellis, 1985) Experiments 1 and 3.

Dominance, Cerebral↗
PubMed1991

Statistical constraints on the use of single cases in neuropsychological research.

In a recent study by Miceli, Silveri, Romani, and Caramazza (Brain and Language, 1989, 36, 447-492), free speech records for 20 unselected Italian-speaking agrammatic patients were analyzed along a variety of linguistic parameters, with particular emphasis on substitution and omission errors within traditional "part of speech" categories. The authors draw two strong conclusions: (1) the variability observed in this sample is too great to justify grouping these patients (or any coherent subset of the patients) into the "same" clinical category; (2) the extensive variability displayed by these patients reflects meaningful and very specific patterns of dissociation that would be lost if patients were grouped together in a common category called "aggrammatism." In a reanalysis of the Miceli et al. data, we conclude that the evidence does not justify either of these conclusions. First, we provide a set of mathematical simulations demonstrating that the dissociations claimed by Miceli et al. could have occurred entirely by chance, if samples of speech were drawn randomly from a "universe of discourse" characterized by error rates similar to those displayed by patients in this study. This randomization method has considerable generality, and could prove useful to other investigators interested in determining the number and type of dissociations that are likely to occur by chance in individual and/or group studies. Second, we demonstrate that there are many confounding factors that could account for the variability observed by Miceli et al., including differences in neurological status, education, and the strategies that patients elect to deal with their limitations.

Aphasia, Broca↗
PubMed1985

Origins of language delay in abused infants.

This paper presents a reanalysis of data collected in a study of abusing mother-infant pairs, emphasizing the failure of infants with a history of physical abuse to develop appropriate language skills. Bayley Mental Development indices of abused infants decreased with age. This decrease was attributable largely to the failure of abused infants to pass verbal items. None of the abused children had any verbal communication skills. Results are discussed in relation to patterns of maternal ignoring and lack of verbal stimulation.

Age Factors↗