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PubMed1998

Mannose ligand receptor assay as a test to predict fertilization in vitro: a prospective study.

OBJECTIVE: To assess whether mannose receptor assays can predict fertilization outcome in vitro. DESIGN: A prospective, double-blind study of the mannose receptor properties of spermatozoa. SETTING: Assisted human reproduction program at a university hospital. PATIENT(S): Partners of 140 consecutive women undergoing their first in vitro fertilization cycle. INTERVENTION(S): Motile sperm populations were tested for surface receptors for mannose by measuring their ability to bind fluorescein-labeled mannosylated albumin and to undergo a free mannose-induced acrosome reaction as judged by Pisum, sativum agglutinin binding. MAIN OUTCOME MEASURE(S): Mannose receptor assay results were correlated with fertilization outcomes using several statistical tests, including the chi2 test, chi2 for proportions, t-tests, analysis of variance with Student-Newman-Keuls tests and correlational and receiver operating characteristic (ROC) curve analysis. RESULT(S): The fractional increment increase on incubation in the percent of sperm binding mannose ligand over an intact acrosome correlated with fertilization rates in vitro. Threshold values of mannose ligand binding and of mannose-induced acrosome reactions predictive of fertilization rates were identified by ROC curve analysis. Men were thus classified into one of four groups with differing fertilization rates in vitro. CONCLUSION(S): The increment increase in sperm surface mannose ligand binding by acrosome-intact sperm correctly predicts high and low fertilization rates in vitro and identifies cases where conventional insemination can result in failed fertilization.

Adult↗
PubMed2003

Gene annotation: prediction and testing.

Fifty years after the publication of DNA structure, the whole human genome sequence will be officially finished. This achievement marks the beginning of the task to catalogue every human gene and identify each of their function expression patterns. Currently, researchers estimate that there are about 30,000 human genes and approximately 70% of these can be automatically predicted using a combination of ab initio and similarity-based programs. However, to experimentally investigate every gene's function, the research community requires a high-quality annotation of alternative splicing, pseudogenes, and promoter regions that can only be provided by manual intervention. Manual curation of the human genome will be a long-term project as experimental data are continually produced to confirm or refine the predictions, and new features such as noncoding RNAs and enhancers have not been fully identified. Such a highly curated human gene-set made publicly available will be a great asset for the experimental community and for future comparative genome projects.

Alternative Splicing↗
PubMed1999

The principles of medical ethics and medical research.

In this paper I discuss the application of the principles of medical ethics and of medical research to the case of children and others whose consent to treatment and to research is problematic. Public health depends substantially on the possibility of ongoing research into all conditions which affect the health of the people. Constraints on this research are therefore a public health issue. Moreover and more importantly the possibility of predictive testing and indeed of screening for health-relevant conditions is an important public health tool, and limitations on the use of this tool are of great significance to public health medicine. Having considered the particular problems created by research and predictive testing on children for late-onset conditions I go on to discuss research on those whose consent is problematic more generally. I conclude with radical recommendations for the reform of The Declaration of Helsinki and of the International Ethics Guidelines for Biomedical Research Involving Human Subjects, prepared by the Council for International Organizations of Medical Sciences (CIOMS).

Adult↗
PubMed2002

Sensitization methodology and primary prevention of the research institute for fragrance materials.

The Research Institute for Fragrance Materials Inc. (RIFM) has approached sensitization studies with fragrance materials as primary prevention of sensitization in the healthy, normal population. Secondary prevention, or avoidance of elicitation, most often suggested by dermatologists for patients presenting with dermatitis, has not been part of its program effort. Historically, RIFM evaluated the sensitization potential of fragrance materials using the human maximization test method; no animal models were used. In general, petrolatum was used as the vehicle. This is a harsh procedure whose main use may provide a measure of the uppermost limits of sensitization. Treating skin with sodium lauryl sulfate may be problematic and finding a laboratory to conduct the study may also be difficult. In addition, using a human predictive test method for both hazard and safety assessments is not ideal. The current practice involves a hazard assessment using an animal model, followed by a safety assessment in a human repeated-insult patch test (HRIPT). The animal test method is used to identify the sensitization potential and a no-effect level. Following a review of the no-effect level and the maximum skin level, a safety assessment in humans can be conducted. RIFM also modified the original vehicle used in sensitization testing, since petrolatum presents two major difficulties: solubility and inconsistent effects on skin penetration. Since the greatest exposure to fragrance materials is considered to be from a cologne-type product, ethanol was chosen as a more realistic vehicle. Further modification resulted in combinations of ethanol and diethyl phthalate, due to diethyl phthalate's use in many perfume formulations as a solvent and fluidizer. Human testing should not be conducted as a hazard assessment. If conducted as a safety study, induction of sensitization should be a rare occurrence. Thus, follow-up studies are not meaningful since the number of sensitized volunteers would be low. However, following a series of the RIPTs with various concentrations of hydroxycitronellal, RIFM identified a group of 41 individuals who became sensitized. An extensive 3-phase use study, with 3 diagnostic patch tests and 4 whole-body dermatological examinations showed that most subjects were able to use a bar soap, a moisurizing lotion and cologne-type products with up to 1% hydroxycitronellal. In subjects where sensitization was induced by predictive testing, no serious recurring adverse dermatological conditions developed.

Allergens↗
PubMed2001

Quantitative analyses of SMN1 and SMN2 based on real-time lightCycler PCR: fast and highly reliable carrier testing and prediction of severity of spinal muscular atrophy.

Spinal muscular atrophy (SMA) is a common autosomal recessive disorder in humans, caused by homozygous absence of the survival motor neuron gene 1 (SMN1). SMN2, a copy gene, influences the severity of SMA and may be used in somatic gene therapy of patients with SMA in the future. We present a new, fast, and highly reliable quantitative test, based on real-time LightCycler PCR that amplifies either SMN1 or SMN2. The SMN1 copies were determined and validated in 329 carriers and controls. The specificity of the test is 100%, whereas the sensitivity is 96.2%. The quantitative analysis of SMN2 copies in 375 patients with type I, type II, or type III SMA showed a significant correlation between SMN2 copy number and type of SMA as well as duration of survival. Thus, 80% of patients with type I SMA carry one or two SMN2 copies, and 82% of patients with type II SMA carry three SMN2 copies, whereas 96% of patients with type III SMA carry three or four SMN2 copies. Among 113 patients with type I SMA, 9 with one SMN2 copy lived <11 mo, 88/94 with two SMN2 copies lived <21 mo, and 8/10 with three SMN2 copies lived 33-66 mo. On the basis of SMN2 copy number, we calculated the posterior probability that a child with homozygous absence of SMN1 will develop type I, type II, or type III SMA.

Adolescent↗
PubMed1994

The local lymph node assay: developments and applications.

The murine local lymph node assay is a predictive test method for the identification of contact allergens in which sensitizing activity is measured as a function of induced proliferative responses in lymph nodes draining the site of application. In this article the development and validation of the assay are described and comparisons with guinea pig predictive test methods discussed. In addition we examine the advantages and limitations of the method and consider new opportunities and applications of the assay in the context of the toxicological evaluation of sensitizing potential.

Allergens↗
PubMed1992

The murine local lymph node assay: a commentary on collaborative studies and new directions.

The murine local lymph node assay is a predictive test for the identification of contact allergens. This paper provides a historical background to the development of the assay and describes the performance of a recently completed interlaboratory trial designed to evaluate further the utility of the method as an alternative or adjunct to guinea-pig predictive tests. On the basis of these and supplementary investigations, a number of recommendations can be made regarding the use and interpretation of the local lymph node assay. Finally, a number of issues arising from recent studies are discussed, including comparisons of the local lymph node assay with guinea-pig methods.

Allergens↗
PubMed1994

[The skin autologous microflora index as a test for predicting acute morbidity in mass medical examinations of workers].

Basing on assessment of skin microflora in 3186 apparently health able-bodied individuals and on subsequent study of acute morbidity, the authors revealed direct dependence between these parameters: only 3.4% of people with normal level of microflora became ill during 1 month after the examination, the value of those with higher level was 15.5%. Therefore the skin microflora test could serve for prognosis.

Acute Disease↗
PubMed2006

Use of a general toxicity test to predict heavy metal concentrations in residential soils.

Significant clusters of developmental delay and mental retardation (DD/MR) were identified in children born in South Carolina. Although it is difficult to identify one factor that causes DD/MR, environmental insult including exposure of pregnant women to heavy metals can induce DD/MR in their children. Because it is expensive to measure the concentrations of individual metals in large numbers of environmental samples, the general Microtox toxicity test was used to identify highly toxic soil samples. Approximately 100 soil samples were collected from residential areas and analyzed to determine an effective concentration (EC(50)) of soil required to inhibit 50% light emission of the luminescent bacterial test organism (Vibrio fischeri). The EC(50) values were then transformed to relative toxicity units (RTU). A subset of 56 high and low toxicity soil samples was then analyzed by inductively coupled plasma-atomic emission spectrometry (EPA method 6010) for arsenic, lead, and chromium, which are known neurotoxins. The highest measured arsenic concentration was 30 times higher than the South Carolina residential soil limit. Significant correlations were found between the RTU and soil arsenic and chromium concentrations. Microtox also identified some low arsenic and chromium samples as toxic, presumably because additional unidentified toxicants were present in the soil. In general, however, the Microtox test was effective in identifying soils with elevated concentrations of arsenic and chromium, even in residential neighborhoods where limited soil toxicity was expected.

Aliivibrio fischeri↗
PubMed2006

Relationship between sexual behavior classifications of rams and lambs sired in a competitive breeding environment.

The objectives for this study were to 1) determine the relationship between sexual performance class and lambs sired in a competitive mating environment, and 2) determine whether the male-oriented ram test is valid. Fifteen 2- to 3-yr-old whitefaced rams classified as female-oriented, with high or low sexual performance, or classified as male-oriented were used in a multiple-sire breeding arrangement. Five groups of approximately 200 ewes each were exposed for 21 d to 3 rams per group consisting of 1 ram from each class. Rams were blocked for sexual class, and those with close genetic relationship were assigned to different pens. Genomic DNA was prepared from blood collected from 15 rams, 934 ewes, and 1,757 lambs. Up to 4 microsatellite markers were used to determine a lamb's sire. Of 884 ewes with identifiable lambs (known sires), 178 ewes had single lambs, 408 had multiples sired by 1 ram, and 298 had multiples sired by more than 1 ram. The sexual partner preference test used to identify male-oriented rams did not absolutely reflect their sexual performance during competitive breeding. In contrast to only mounting and servicing males in preference tests before breeding, male-oriented rams sired 480 lambs from 330 ewes. Serving capacity tests predicted sexual performance of high and low sexual performance rams. High performance rams impregnated more ewes (499 vs. 258; P < 0.05) and sired more lambs (756 vs. 357; P < 0.05) than did low performance rams, respectively. Low performance and male-oriented rams did not differ for ewes impregnated or lambs sired. We conclude that 1) sexual partner preference tests used to classify male-oriented rams were not absolute in reflecting their breeding performance in a competitive breeding environment; 2) serving capacity tests predicted that high performance rams would breed more ewes than low performance rams and sire more lambs than either low performance or male-oriented rams; and 3) under the conditions of this study, low performance and male-oriented rams did not have an adverse impact on the overall breeding outcome. Combined, low performance and male-oriented rams sired 81 more lambs than did high performance rams, but this required twice as many rams to obtain approximately equal breeding results. Therefore, we suggest that serving capacity tests should be used to select high performance rams, reduce number of rams with marginal sexual performance, and make decisions on ram numbers needed.

Animals↗
PubMed2002

Validation of the NFL-225 test for predicting 1-RM bench press performance in college football players.

BACKGROUND: The purpose of this study was to evaluate the accuracy of repetitions-to-fatigue (RTF) using an absolute load of 102.3 kg (225 lbs) to estimate one-repetition maximum (1-RM) bench press performance in college football players using various prediction equations. METHODS EXPERIMENTAL DESIGN: a prospective study on the association between muscular endurance and muscular strength. PARTICIPANTS: 260 players from NCAA Division IA (n=43), IAA (n=63), II (n=129), and red-shirts (n=25) were evaluated at the conclusion of a minimum of eight weeks of heavy-resistance training during the off-season. MEASURES: all subjects performed a 1-RM bench press and RTF using an absolute load of 102.3 kg. RESULTS: The Mayhew et al. NFL-225 equation nonsignificantly overestimated 1-RM from RTF by 0.5 kg, while the Chapman et al. NFL-225 equation significantly underpredicted by 3.2 kg, although both equations were comparable in the number of players predicted within +/-4.5 kg of actual 1-RM (52% vs 51%, respectively). Only two of nine RTF equations currently in use produced predicted 1-RM values that were not significantly different from actual 1-RM performance. CONCLUSIONS: Specific NFL-225 equations are more accurate in estimating 1-RM bench press from absolute muscle endurance in college football players than previous published RTF equations. The accuracy of prediction decreases at higher repetitions.

Adolescent↗
PubMed2000

The knowledge acquired during artificial grammar learning: testing the predictions of two connectionist models.

An artificial grammar learning experiment is reported which investigated whether three types of information are learned during this kind of task: information about the positions of single letters, about fragments of training strings, and about entire training strings. Results indicate that participants primarily learned information about string fragments and, to a lesser extent, information about positions of letters. Two connectionist models, an autoassociator and a simple recurrent network (SRN), were tested on their ability to account for these results. In the autoassociator simulations, similarity of test items to entire training items had a large effect, which was at variance with the experimental results. The results of the SRN simulations almost perfectly matched the experimental ones.

Adult↗
PubMed1992

Aging as a multi-step process characterized by a lowering of entropy production leading the cell to a sequence of defined stages. II. Testing some predictions on aging human fibroblasts in culture.

The concepts of irreversible thermodynamics have been used in order to develop a theory of aging considered as a multi-step process leading the cell through a sequence of defined stages characterized by a lower level of entropy production and finally to a critical level of errors involving cell death (Toussaint et al., 1991). One of the predictions of this model is that external stresses which can be considered as fluctuations would accelerate the evolution of the cell from one state to the other according to the intensity of the stress. Seven morphotypes have been observed in the serially cultivated human fibroblasts, cells passing progressively from one morphotype to the other. In this paper, we experimentally tested the effect of two different molecules, tert-butylhydroperoxide and ethanol, in order to determine their influence on the shift from one morphotype to the other. When applied for a single period of time on cultivated cells, both molecules effectively showed a modification in the pattern of the different morphotypes which was dependent on the stress intensity: a decreased proportion of the early morphotypes and an increased proportion of the late and post-mitotic morphotypes were observed within three days after the stresses. Similar results were obtained when successive stresses were performed at every subculture. The results also indicated that all stages are not equally stable with morphotypes III and IV being the most stable. The positive effect on the increased shift of these cells from one morphotype to the other by two different stresses firms one of the prediction of the thermodynamic model which states that cellular aging can be considered as a multi-step process which can be speeded up by various external modifications.

Cell Division↗
PubMed2003

Lithium dose prediction based on 24 hours single dose levels: a prospective evaluation.

The authors present the results of the utilization of a pharmacokinetic prediction test for lithium posology. Based on a single point (plasma lithium determination 24 h after a single dose) such a test aims to adapt the posology as soon as the second day of treatment rather than after one week as clinicians must wait for a steady state to be achieved. Built on the previous work of Perry, the test targeted the plasma lithium level at 0.8 +/- 0.1 mmol l(-1). Thirty-one patients took part in the study. There were two drop-out cases and the results were available for 29 patients: among them, 51% had their plasma level in the targeted zone. Although there was no control group, the prediction test often allowed us to use a higher dose than the usual fixed dose whose amount is limited by the risk of overdosing for the slower metabolizers.

Adult↗
PubMed1999

Sensitizing potential in mice, guinea pig and man of the preservative Euxyl K 400 and its ingredient methyldibromo glutaronitrile.

The allergenicity of the preservative Euxyl K 400 and its principal allergen methyldibromo glutaronitrile (MDBGN) (1,2-dibromo-2,4-dicyanobutane) was investigated using 3 animal models; in mice, the local lymph node assay (LLNA) and in guinea pigs, the guinea pig maximization test (GPMT) and the cumulative contact enhancement test (CCET) with a dose-response protocol included. Previous attempts to define the sensitization capacity of these chemicals have given conflicting results. For comparison, the frequency and causes of positive patch test reactions to Euxyl K 400 and MDBGN were studied in patients referred to an occupational dermatology clinic. This investigation showed that Euxyl K 400 and MDBGN can give rise to contact allergy in man and that the relevant cases found mainly had similar exposure as non-occupational cases. A contact allergenic potential could be detected for MDBGN in 2 animal models, i.e., the CCET and the LLNA, and also for Euxyl K 400 in the LLNA. However, statistical analysis of the results from the GPMT with MDBGN failed to detect the sensitizing potential of this particular allergen. The results indicate that to be able to detect the allergenic potential of Euxyl K 400 and MDBGN, a predictive test method with multiple topical applications at induction is required. It is therefore important that an investigator is aware of the possibility of using various predictive test models for investigation of potential contact allergens.

Allergens↗
PubMed1989

A murine local lymph node assay for the identification of contact allergens. Assay development and results of an initial validation study.

The development of an alternative predictive test for the identification of contact sensitizing chemicals is described. The method is based upon the fact that, following epicutaneous application, sensitizing chemicals initiate a primary immunological response in the draining lymph node(s) which is characterized by lymphocyte proliferation. Experimental conditions for the measurement in vitro of the induced lymph node cell proliferative response have been optimized. On the basis of the data presented a local lymph node assay was developed in which CBA/Ca strain mice were exposed daily, for 3 consecutive days, to various concentrations of the test chemical, or to vehicle alone, on the dorsum of the ear. Lymph node activation was measured subsequently as a function of increased node weight, the frequency of large pyroninophilic cells and lymphocyte proliferation in the presence or absence of an exogenous source of interleukin 2 (IL-2). The results of a validation study are reported in which 22 well-characterized sensitizing chemicals of varying potency were examined. With the exception of three chemicals where water was used as the application vehicle, positive responses, defined as a substantial increase in lymphocyte proliferative activity, were recorded with all these test materials. Under the conditions employed non-sensitizing chemicals, including non-sensitizing irritant chemicals, failed to influence the immunological status of the draining lymph node. Taken together, the data suggest that the local lymph node assay provides the basis for a rapid and cost-effective alternative to the currently available guinea pig predictive test methods. The local lymph node assay may be of particular value for the evaluation of coloured or irritant chemicals.

Allergens↗