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At least 73 records · Page 4Linked to original sources
PubMed1979

Assay of major and minor constituents of opium samples and studies of their origin.

Samples of opium from different countries as well as from various regions of India were studied for their morphine and codeine content by gas-liquid chromatography (GLC) as their silyl ethers in a single step. Non-phenolic alkaloids (thebaine, papaverine and narcotine) were extracted with dichloromethane for GLC after conversion of the meconic acid, morphine and codeine in opium into insoluble salts with lime water. The data on alkaloidal constituents have been utilised in a determination of the origin of seized opium samples in this preliminary study.

Alkaloids↗
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↗
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↗
PubMed1990

Aerobic biodegradation of vinyl chloride in groundwater samples.

Studies were conducted to examine the biodegradation of 14C-labeled vinyl chloride in samples taken from a shallow aquifer. Under aerobic conditions, vinyl chloride was readily degraded, with greater than 99% of the labeled material being degraded after 108 days and approximately 65% being mineralized to 14CO2.

Aerobiosis↗
PubMed1992

Factual knowledge about AIDS and dating practices among high school students from selected schools.

Following various educational strategies by governmental and non-governmental organisations to educate youths and school teachers about HIV infection and prevention, this KABP survey was one attempt to evaluate the results. The study sample of 478 high school students was drawn from four randomly selected schools in Mashonaland and Matabeleland including high and low density, government and mission co-educational schools. The sample was randomly selected and stratified to represent sex and grade level. The KABP self administered questionnaire was used. The paper analyses the relationship between the knowledge and dating patterns. Generally, respondents demonstrated a 50pc to 80pc accuracy of factual knowledge. Of the 66pc Forms I through IV pupils who dated, 30pc preferred only sexually involved relationships and a small number considered the possibility of HIV/AIDS infection. A theoretically based tripartite coalition involving the school, the family health care services for education, guidance and support to promote responsible behaviour throughout childhood was suggested.

Acquired Immunodeficiency Syndrome↗
PubMed1991

[Phase III study--current status and problems].

Phase III studies are the last step in evaluation of the new drugs or treatment modalities, and have one of the following purposes: 1) to determine the effect of a treatment relative to the natural history of the disease; 2) to determine whether a new treatment is more effective than a standard therapy; 3) to determine whether a new treatment is as effective as a standard therapy but is associated with less toxicity. In general, a phase III study is performed in a disease-oriented prospective randomized setting. The design of phase III study is described in this paper. In designing a trial, we must decide the endpoints which are appropriate for comparison of each treatment. The endpoints for phase III study include tumor shrinkage, disease-free survival, overall survival, toxicity and quality of life. In a phase III study, it is very important to determine how many patients should be studied (sample size). The sample size that will be needed for each endpoint depends on the expected difference between the standard and the experimental arms. Once the required number of patients is determined, the investigator must verify that there will be enough patients available to complete the trial. The most common cause of an uninterpretable result in these trials is the accrual of too few patients to make a definitive statement.

Antineoplastic Agents↗