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At least 127 records · Page 7Linked to original sources
PubMed1980

Drug use and drug problems among teenagers in a household sample.

Studies of drug use among young persons have typically employed students or special high risk groups rather than general samples. This study reports drug use among a household sample of persons aged 14 to 18. The results indicate that cannabis was the most frequently used drug. Factors associated with drug problems were: being older, living in cities, not participating in religious activities and being a worker rather than a student. Very few of those with problems had been treated or felt the need for any treatment.

Adolescent↗
PubMed1985

[Semen evaluation: technic of study].

Sampling precautions are particularly important in the study of sperm: the length of sexual abstinence, complete collection of the ejaculate, sampling by masturbation in the laboratory. The examination of sperm consists of different steps: measurement of the ejaculate volume, evaluation of the mobility, speed, and propulsion direction of the spermatozoa, study of spermatozoon concentration, estimation of the percentage of live spermatozoa, morphological examination of the spermatozoa, including an enumeration of the abnormal forms, evaluation of spermatozoon survival in vitro for 24 h by monitoring the percentage of mobility every 2 h. This examination can be complemented by biochemical and enzymatic assays of: fructose, zinc, carnitine, citric acid, acid phosphatase, alpha glucosidase, which serve as tracers of associated secretions.

Cell Survival↗
PubMed1989

Ultrastructure of spermatozoa & non spermatozoal cells in human semen in genital tract infections.

With a view to ascertain the possible etiology fo the morphological abnormalities seen in spermatozoa of semen from genital tract infections, 16 semen samples were studied. Samples were selected on the basis of each of them having 10-12 pus cells per high power field. Apart from routine semen analysis, the sperms were subjected to electron microscopic studies. Alterations in the ultrastructure of spermatozoa and non-spermatozoal constituents of the infected semen samples were studied. The possible etiology of a wide spectrum of abnormalities in semen found to be associated with genital infection is discussed.

Genital Diseases, Male↗
PubMed1987

Prevalence of diabetes mellitus and impaired glucose tolerance among second-generation Japanese-American men.

We describe the initial findings from a multidisciplinary, epidemiologic study of diabetes mellitus conducted in a population of second-generation Japanese-American (Nisei) men born between 1910 and 1939 who reside in King County, Washington (n = 1746). From this study population, 487 volunteered, and 229 were enrolled to comprise the study sample. A random sample of Nisei men was also drawn from the population to develop a reference sample of 189 men. All subjects participated in a 75-g oral glucose tolerance test; the National Diabetes Data Group (NDDG) and World Health Organization (WHO) diagnostic criteria as well as a modification of the WHO criteria were used to classify individuals with normal glucose tolerance, impaired glucose tolerance (IGT), or diabetes. Within the study sample, 79 men were found to have normal glucose tolerance, 72 had IGT, and 78 had type II diabetes. The mean age of the study sample was 61.4 yr. Based on comparison of the study sample to the reference sample, the study sample was ascertained to be representative of Nisei men in King County. Extrapolating from our observations in the reference sample and in the study sample, we have estimated that approximately 56% of Nisei men in the study population have abnormal glucose tolerance. Much of this is undiagnosed because only approximately 13% of the reference sample of Nisei men reported a prior diagnosis of diabetes. Of the men who enrolled in the study as nondiabetic subjects, 11.1% had diabetes and 39.2% had IGT; i.e., 50.3% had previously unknown abnormalities in glucose tolerance. We estimate that approximately 20% of Nisei men have diabetes (both previously diagnosed and undiagnosed) and approximately 36% have IGT.

Adult↗
PubMedDate not supplied

[Homogenization of samples for the culture of mycobacteria. A comparative study of samples with and without centrifugation].

A homogenization method for sputum samples for the culture of acid-fast bacilli that omits the use of centrifugation, passage test tubes and balances is described. 10% sodium phosphate was used as decontaminating substance. This method facilitates the laboratory work since the samples so treated are incubated at 37 degrees C up to the next day when they are then cultured. 676 samples prepared according to this method were compared with samples prepared according to the standard method; a 6,21% positivity in the former compared to a 5,47% in the latter as well as a lower percentage of contamination were obtained. Contamination occurred in 9,91% of samples without centrifugation and in 14,35% of centrifuged samples.

Bacteriological Techniques↗
PubMed2025

Identification of Sample Processing Errors in Microbiome Studies Using Host Genetic Profiles.

In microbiome studies, sample processing errors are frequent and difficult to detect, especially in large studies involving multiple sites, personnel, and sample types. We present two complementary approaches to identify such errors using host DNA profiled via metagenomic sequencing of microbiome samples. The first approach compares host SNPs inferred from metagenomics to independently obtained genotypes (e.g., microarray genotypes) to match samples to their donors, while the second method compares metagenomics-inferred SNPs between samples to identify samples supplied by the same donor. Furthermore, we demonstrate that combining these methods with experimental metadata provides greater confidence in the identification of errors. Analyzing a longitudinal vaginal microbiome dataset, we demonstrate the ability of our approach to identify mislabeled samples. Using subsampling, we further show that our methods are robust to low sequencing coverage. Overall, our analysis highlights the frequency of processing errors in microbiome studies. We therefore recommend applying error-detection methods in all studies with suitable data.

Journal Article↗
PubMed1988

Disease based spectrum bias in referred samples and the relationship between type A behavior and coronary artery disease.

Using referred samples to study predictors of disease produces statistical problems that reduce the likelihood of obtaining statistically significant results even when a substantial relationship is present between a risk factor and a disease. The present paper refers to these problems as disease based spectrum (DBS) bias. DBS bias is present when subjects are directed into or excluded from the study sample according to their disease status. For example, healthy individuals are excluded from and diseased individuals are directed into referred samples. Therefore, DBS bias is present in referred samples. Examples from the literature on Type A behavior and coronary artery disease (CAD) are presented to illustrate how DBS bias reduces statistical associations. The results of the current research indicate DBS bias has reduced the association between Type A behavior and CAD in a number of studies reported in recent years. In addition, the present article discusses techniques for assessing and controlling for DBS bias.

Age Factors↗
PubMedDate not supplied

Crystalloid structures in retroperitoneal paragangliomas: a light and electron microscopic study.

Samples from three clinically functional retroperitoneal paragangliomas were studied by light and electron microscopy. The tumors exhibited a Zellballen pattern histologically, and ultrastructurally all three neoplasms consisted of cells containing catecholamine granules. Prominent cytoplasmic crystalloids were present in all cases. The crystalloids were identified in routine histologic sections, demonstrated eosinophilia, and stained with periodic acid-Schiff, Giemsa, phloxine-tartrazine, and azan stains. Ultrastructurally the crystalloids were osmiophilic, often appeared as slender needles, were membrane bound, and demonstrated a periodicity of 9 nm. The crystalloids, unlike the catecholamine granules, were negative for catecholamine fluorescence. X-ray microanalysis, however, revealed the selective presence of chromium in both catecholamine granules and crystalloids.

Adult↗
PubMed1983

The nutritional composition of British bread: London area study.

Samples of white and brown bread, both sliced and unsliced, and of wheatgerm breads and wholemeal bread were purchased in London and analysed for a wide range of nutrients. Available carbohydrate, dietary fibre, fatty acids, riboflavin, vitamin B6, and iodine were determined in bulked samples of each type of bread and, in addition, every loaf was analysed for moisture, fat, protein, phosphorus, chloride, sodium, potassium, calcium, magnesium, iron, zinc, copper, manganese, thiamin, nicotinic acid, and free and total folic acid, in order to provide an estimate the variability within each kind of bread. Virtually all the constituents that were measured in the individual loaves showed inter-loaf variation--particularly moisture contents and the levels of calcium, copper and folic acid. Unsliced loaves were more variable than sliced loaves but when expressed on a dry matter basis there were no significant differences in the nutrient levels in sliced and unsliced breads. Wheatgerm breads were relatively more homogenous products but wholemeal loaves were very unhomogenous reflecting the difficulty of accurately identifying unwrapped wholemeal loaves in retail outlets. Some differences from previously published values for all breads were found for dietary fibre, iron, thiamin and vitamin B6. Experience of sampling at retail outlets and analysis provided by this study will be integrated into the design of a planned study of breads throughout Britain.

Bread↗
PubMed1988

Avoidance of contamination in element analysis of serum samples.

The selection of sampling needles and plastic material used for the storage of serum samples were studied. Sampling needles and plastic material were analyzed by neutron activation analysis. Leaching of elements from containers by acids and EDTA-solution was also followed. Also the long-term storage of serum samples for element analysis was investigated. Zn, Cu and Se concentration of serum was followed over the course of four years. The selection of sampling needles, as well as all plasticware which comes into contact with the serum, should be based on the knowledge of possible removal of elements from materials into the sample. Storage of serum samples at -18 degrees C does not change the copper, zinc or selenium concentration over the course of 4 years despite repeated melting and refreezing of the samples.

Blood Chemical Analysis↗
PubMed1990

Orthodontics and temporomandibular disorders: a review of the literature (1966-1988)

The orthodontist has been both accused of causing and complimented for curing temporomandibular dysfunction. To better understand the origins of these conflicting opinions, a review of the orthodontic and temporomandibular joint journals was performed for articles published since 1966. A total of 91 publications that discussed the relationship between orthodontics and temporomandibular disorders was found, and these articles were divided in three categories: viewpoint publications, case reports, and sample studies. Among the areas scrutinized in each category was the method that has led to the diversity of viewpoints. From this analysis, the following conclusions were drawn: (1) viewpoint publications and case reports were excessively represented in comparison with the number of sample studies; (2) viewpoint publications and case reports described a wide variety of conflicting opinions on the relationship between orthodontics and temporomandibular disorders; (3) unlike sample studies, viewpoint publications and case reports have little or no value in assessment of the relationship between orthodontics and temporomandibular disorders; (4) sample studies indicate that orthodontic treatment is not responsible for creating temporomandibular disorders, regardless of the orthodontic technique; and (5) sample studies indicate that orthodontic treatment is not specific or necessary to cure signs and symptoms of temporomandibular dysfunction.

Humans↗
PubMedDate not supplied

On the homogeneity of personality disorder clusters.

This study was conducted using as subjects persons seeking psychiatric care in a public intake facility. Patients who received a diagnosis of a personality disorder (PD) on axis II constituted the study sample. The study is unique in that it attempts to analyze in a treatment population the relationships between all of the personality disorders (PD) stipulated in DSM-III with emphasis on their relationships to the associated features recorded in the remaining axes of DSM-III. The specific aim of the study was to determine the variation that exists with respect to clinical and demographic variables across the PD clusters categorized in DSM-III and across the PD types of each of the DSM-III PD clusters. In general, considerable inhomogeneity was shown within and across clusters in both demographic and clinical variables, although differences among clusters were noted as well. Cluster B differs prominently from its cohorts with respect to demographic and clinical characteristics. Some of the limitations of these results are emphasized.

Adult↗
PubMed1977

Improved estrogen receptor assay in human mammary cancer. Technics for handling small tissue samples.

Studies of various technics that aid in performing estrogen receptor assays on small tissue samples from primary cancers of the breast are reported. It is shown how sufficient protein can be obtained from less than 100 mg of small primary tumor without ultracentrifugation to assay estrogen receptor by a simplified two-point Scatchard plot method. The resulting Kd and maximum binding site values with 36 tumor tissue samples approximated the values obtained with the more laborious, larger tissue sample-demanding six-point Scatchard plot. Target and nontarget tissue controls are easily included in an assay run of four to eight samples. For interpretive purposes the derivation of the characterizing value of the Kd for estrogen receptor is given and compared with nonspecific associating binders.

Animals↗
PubMed1975

Temporal lobe epilepsy and aggression.

Research on temporal lobe epilepsy (TLE) and aggression is reviewed in order to learn why it has not contributed more to our understanding of the neural basis of aggression. The research problem can be resolved into two questions: Are temporal lobe epileptics more aggressive? What inferences can be drawn about the factors underlying aggression in TLE? Difficulties in finding suitable operational definitions for TLE and for aggression have, to date, received insufficient attention. In published studies, sample bias and lack of regard for the validity and reliability of behavioral assessments prevent our deciding whether an association exists between interictal aggressive behavior and TLE. Even if this association were demonstrated, one could not draw direct neurobehavioral inferences from it, since a variety of social and psychological, as well as neurophysiological variables could contribute to the association. These would have to be controlled. Methodological refinements could lead to more satisfactory answers to the first question, but the second is considerably more difficult. Some sources of complexity and apparent contradictions in the experimental literature on the neurology of aggression are discussed. They consist of technical problems, the complexity of the neural substrate of aggression and the influence of environmental cues and learning. The combined use of electrophysiological and interview techniques has yielded some interesting results with TLE patients.

Age Factors↗
PubMed1990

Rapid detection and further characterization of infection with hepatitis B virus variants containing a stop codon in the distal pre-C region.

Recently, hepatitis B virus (HBV) replication in the absence of HBe antigenaemia has been attributed to HBV variants with a TAG stop codon in the distal pre-C region associated with one or two point mutations. We describe here a rapid detection method for the diagnosis of such HBeAg-negative HBV variants using selective oligonucleotide hybridization. The entire pre-C region was amplified by the polymerase chain reaction and hybridized under stringent conditions with non-mutated (M0), one (M1) and two (M2) point-mutated oligonucleotide probes. Of the 15 HBeAg-positive (group I) and 20 HBeAg-negative (group II) serum samples studied, 14 samples in group I and one sample in group II hybridized with M0 only and 18 samples in group II hybridized with M1 or M2, or both. The remaining two samples (from groups I and II, respectively) failed to hybridize with any of the three probes. DNA sequencing confirmed mixed distal pre-C sequences in samples hybridizing with more than one probe and also revealed novel mutations in the distal pre-C region of the two samples which failed to hybridize with any of the probes. The latter sample had a +2 frameshift and hence represented a new type of HBeAg-negative HBV variant. This method may therefore prove useful in the diagnosis of infections by HBeAg-negative HBV variants resulting from common mutations in the pre-C region, as well as for the identification of less common variants with novel mutations in the same region.

Base Sequence↗
PubMed1990

Very high blood pressure in acute stroke.

In a study sample consisting of 388 unselected, consecutive acute stroke patients, 27 with systolic blood pressure greater than or equal to 200 mmHg and diastolic blood pressure greater than or equal to 115 mmHg were compared with the other 361 patients. The patients with high blood pressure were younger (65 vs. 73 years) and much more often had a history of hypertension (78 vs. 42%). Cardiac and vascular hypertensive manifestations were more frequent, particularly when only those patients with a history of hypertension were compared in the two groups. Alcohol abuse was mentioned in a higher proportion of hypertensives in the summaries of their medical records. No definite conclusions could be drawn with regard to the size and location of the brain lesions. Clinical symptoms did not differ between the groups, neither did the proportion of patients who could be discharged from hospital immediately. Mortality was higher in the high blood pressure group (30 vs. 14%, P less than 0.05). Thus the characteristics of patients with very high blood pressure were: younger age, much more frequent and severe previous hypertension. Alcohol abuse might be an important factor. The type, size and location of the brain lesion itself could not be statistically related to the high blood pressure, but very large lesions, particularly haemorrhages, might be associated with a reactive blood pressure response.

Age Factors↗