SEARCH · PubMed Health

Results for “shared variables”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,441 records · Page 80Linked to original sources

PubMed1982

Exercise provocable right ventricular outflow tract tachycardia.

During the past 5 years, we have seen six patients who met inclusion criteria of exertional palpitations, reproducible treadmill (TM) provocable ventricular tachycardia (VT), and performance of electrophysiologic (EP) studies including isoproterenol (ISO) infusion. There were five males and one female, aged 15 to 55 years (mean +/- SD, 31 +/- 18 years). Three patients were trained athletes, two patients had mitral valve prolapse, three had enlarged right ventricular (RV) volumes (all trained athletes), and two had no evidence of organic heart disease. TM testing in all patients demonstrated reproducible exercise-provocable VT of at least 20 beats' duration. TM VT was characterized by left bundle branch block pattern ORS morphology and rates of 150 to 230 bpm (186 +/- 30 bpm). EP did not reproduce VT in five of six patients while ISO at a dose of 2 to 4 micrograms/min (2.5 +/- 0.8 micrograms/min) reproduced VT in all patients. ISO VT was characterized by QRS morphology identical to TM VT and rates of 165 to 230 bpm (191 +/- 26 bpm). Endocardial mapping of ISO VT revealed earliest activity in RV outflow tract. Serial TM testing revealed suppression of TM VT in all six patients on propranolol therapy. Responses to class I drugs were variable and less successful. In summary, we describe a group of patients with common clinical, ECG, and electrophysiologic features who may share a common pathophysiology of VT. Possible mechanisms are discussed.

Adolescent↗

PubMed1995

Position and orientation in space of bones during movement: anatomical frame definition and determination.

This paper deals with methodological problems related to the reconstruction of the position and orientation of the human pelvis and the lower limb bones in space during the execution of locomotion and physical exercises using a stereophotogrammetric system. The intention is to produce a means of quantitative description of joint kinematics and dynamics for both research and application. Anatomical landmarks and bone-embedded anatomical reference systems are defined. A contribution is given to definition of variables and relevant terminology. The concept of anatomical landmark calibration is introduced and relevant experimental approaches presented. The problem of data sharing is also addressed. This material is submitted to the scientific community for consideration as a basis for standardization. RELEVANCE: In order to make movement analysis effective in the solution of clinical problems, a structured conceptual background is needed in addition to standardized definitions and methods. Technical solutions which make data sharing and relevant data banks possible are also of primary importance. This paper makes suggestions in this context.

Journal Article↗

PubMed1994

Blood and sporozoite stage-specific small subunit ribosomal RNA-encoding genes of the human malaria parasite Plasmodium vivax.

Malaria parasites, unlike other eukaryotes, have developmentally controlled distinct small subunit ribosomal RNA (SSUrRNA)-encoding genes (SSUrDNA), sporozoite stage-specific C and blood stage-specific A genes. This report describes characterization of the C and A forms of SSUrDNA from the human malaria parasite Plasmodium vivax. We have aligned and compared these sequences with the reported SSUrDNA sequences of other human malaria parasites to identify the regions with potential for diagnostic probes. The comparison revealed the presence of seven conserved regions (> or = 90% similarity), four highly variable regions (< 60% similarity) and three semiconserved regions. The analysis also revealed that the A and C genes of P. vivax share more similarity with each other, as compared to the A and C genes of P. falciparum. Comparison of the SSUrDNA of human, monkey and rodent malaria parasites revealed that the A genes share more similarity with each other than the C genes share with each other.

Animals↗

PubMed2004

Structural comparison of the integrative and conjugative elements R391, pMERPH, R997, and SXT.

R391 and SXT are members of a group of eleven chromosome-borne conjugative elements found in the gamma-proteobacteria, whose members carry different antibiotic resistance traits. Recent genomic analysis of R391 and SXT revealed a highly conserved 'backbone' encoding integration/excision, conjugative transfer, and regulation functions, augmented by an array of phenotypic traits and transposable elements. In this study, PCR amplification and sequence analysis were employed to investigate the genomic structure of two further MGE of the R391 family, pMERPH (HgR) and R997 (ApR, SmR, SuR). R997 and pMERPH were found to be structurally related to R391 and SXT and share a number of virtually identical regions with them-including putative integration, conjugative transfer, and regulatory determinants-interrupted by variable DNA segments and transposable elements. The presence of a highly conserved backbone in the four elements strongly suggests their origin in a common ancestral element, which itself was a mosaic of sequences related to phages and plasmids. Subsequent genetic recombination and the acquisition of transposable elements resulted in the possession of variable phenotypic traits among the four MGE, and diversification into two distinct lineages, the first one including R391 and pMERPH, the second one containing SXT and R997.

Conjugation, Genetic↗

PubMed2001

An IgM anti-MBP Ab in a case of Waldenstrom's macroglobulinemia with polyneuropathy expressing an idiotype reactive with an MBP epitope immunodominant in MS and EAE.

In a previously described case of Waldenstrom's Macroglobulinemia, complicated by polyneuropathy, the IgM/lambda monoclonal antibody (mAb) was highly reactive with myelin basic protein (MBP). Given our demonstration that V lambda x, a recently described murine lambda variable region gene product, can itself bind MBP as well as confer MBP reactivity to an Ab, the possibility of a shared idiotypy between murine V lambda x and this human IgM/lambda anti-MBP was investigated. We characterized the epitope specificity of the macroglobulinemia patient's MBP-reactive IgM/lambda using indirect ELISA procedures with MBP, a citrullinated isomer of MBP termed C8, or peptide fragments of MBP as the coating antigens and monospecific Ab to V lambda x as the secondary Ab. The patient's MBP-reactive IgM/lambda was recognized by Ab specific for V lambda x and, like murine mAb containing V lambda x bound human MBP but not MBP-C8 nor other common autoantigens such as DNA, thyroglobulin, or actin. The anti-MBP reactivity was selective for MBP peptide 90-170 and preferentially recognized MBP peptide 84-96. Thus, the patient's macroglobulin and perhaps certain other human Ab with a 'V lambda x idiotype' bind to MBP peptide residues 84-96, an immunodominant peptide in multiple sclerosis patients. Such binding may be involved in the pathogenesis of neural damage in patients with neuroimmunologic disorders related to plasma cell dyscrasias or autoimmunity.

Animals↗

PubMed1998

Child feeding and care behaviors are associated with xerophthalmia in rural Nepalese households.

The study examined caregiver-child interactions, intrahousehold food allocation and general child care behaviors and their effect on children's xerophthalmia status in the rural Terai region of Nepal. Seventy-eight households with a child having a history of xerophthalmia (cases) were matched with 78 households with a child of the same age having no history of xerophthalmia (controls). Seven day-long continuous monitoring observations were performed in each household (over 15 months) by trained Nepali observers, focusing on feeding and care of a focus child and his/her younger sibling. Nineteen different behavioral variables were operationalized, including serving method, second helpings, serving refusals, encouragement to eat, request intensity, meal serving order, food channeling, food sharing, positive social behaviors, negative social behaviors, and positive health behaviors. Automatic serving and request intensity were strongly negatively correlated, especially among younger siblings. Children who serve themselves receive less encouragement to eat. Those children who are refused in their requests for food tend to ask for food more frequently, for a longer time, and be less likely to self-serve. Children who eat from a shared plate are less likely to interact with a food server and more likely to self-serve. Negative social behavior towards children is associated with the child having to request food more frequently and a greater likelihood of being refused food. Children who receive positive health care from their caregivers are also more frequently asked if they would like food by the server and are encouraged to eat. Several caregiver child feeding behaviors were related to a child's risk of having past vitamin A deficiency. Controls were much more likely to be served food automatically. Cases were more likely to serve themselves food and have multiple servings of food. Cases were nearly two times more likely than controls to be treated with neglect or harshly, and much less likely than controls to have their health needs receive attention. Examining intrahousehold behavior is critical for understanding the causes of vitamin A deficiency in rural Nepalese children, and has great potential for identifying and improving interventions to improve children's diets and care.

Caregivers↗

PubMed2003

Sequence polymorphism of mitochondrial DNA in Japanese individuals from Gifu Prefecture.

Sequence polymorphisms of the hypervariable region HV1 in mitochondrial DNA (mtDNA) were analyzed in a sample of 137 unrelated Japanese individuals living in Gifu Prefecture (central region of Japan) using polymerase chain reaction amplification and direct sequencing. Eighty-two different haplotypes resulting from 81 variable sites were found in the mtDNA HV1 region between positions 16061 and 16450. The most frequent haplotype (16223T, 16362C) was shared by ten individuals. The genetic diversity and the genetic identity were 0.985 and 0.022, respectively. The C-stretch region located around position 16189 was observed in 23.4% of this population sample. Sequence heteroplasmy at the position 16103 (A/G) was found in one individual.

DNA Fingerprinting↗

PubMed2005

[Variability among pathologists in the histological diagnosis of diffuse interstitial lung diseases].

OBJECTIVE: Diffuse interstitial lung diseases (DILD) form a group of diseases which affect the alveolar interstitial space and share very similar clinical, radiological, and functional features, making lung biopsy essential for establishing diagnosis, prognosis, and treatment in many cases. We aimed to see whether there was agreement in histopathological diagnosis among different groups of pathologists in their assessment of these diseases. MATERIAL AND METHODS: Biopsies were studied from 33 patients suffering from noninfectious, nontumorous DILD. The biopsies had been assessed by 2 groups of pathologists: one specializing in this type of disease and another which was not a specialist group. RESULTS: There was disagreement in the histology reports of 10 out of the 33 cases studied (30.3%): 9 cases in the group of 22 cases of idiopathic interstitial pneumonia (40.9%) and 1 in the group of 3 DILD with known or associated causes. No discrepancies were found, however, in the diagnosis of primary DILD or DILD associated with other, less well-defined processes. CONCLUSIONS: We believe that idiopathic interstitial pneumonias are the DILD which pose most problems for pathologists. Therefore, the study of DILD requires specific dedication by pathologists and other professionals and specialists.

Adult↗

PubMed2000

The difference in patterns of motor and cognitive function in chronic fatigue syndrome and severe depressive illness.

BACKGROUND: Chronic fatigue syndrome (CFS) and major depressive disorder (MDD) share many symptoms and aetiological factors but may have different neurobiological underpinnings. We wished to determine the profile of the biological variables disturbed in CFS and MDD, and identify any critical factors that differentiate the disorders. METHODS: Thirty patients with CFS, 20 with MDD and 15 healthy controls matched group-wise for age and sex were recruited. Subjects were given a detailed battery of motor and cognitive tests, including measures of psychomotor speed, memory and maximal voluntary muscle contraction in both the morning and evening that were balanced to avoid order effects. RESULTS: CFS patients generally performed worse on cognitive tests than healthy controls, but better than patients with MDD. Both patient groups had markedly impaired motor function compared with healthy controls. MDD subjects showed a significantly greater diurnal improvement in maximal voluntary contraction than healthy controls. CONCLUSIONS: Patients with CFS and MDD show similarly substantial motor impairment, but cognitive deficits are generally more marked in MDD. Diurnal changes in some functions in MDD may differentiate the disorder from CFS.

Adult↗

PubMed1984

Variability and conformation of HLA class I antigens: a predictive approach to the spatial arrangement of polymorphic regions.

Comparison of available sequences of HLA-A and HLA-B antigens shows that variable positions are predominantly localized in four segments spanning residues 63-85, 105-116, 138-156, and 177-194. The fourth segment is unique in that it contains no differences between antigens of the same locus. Secondary folding of HLA heavy chain was estimated by three independent predictive methods and areas of defined structure were correlated with the distribution of local hydrophobicity to outline putative internal and external portions. The three analyses each independently predict a high probability for beta structure in the alpha 1, alpha 2, and alpha 3 domains. A single alpha-helix is predicted within residues 146-160, a segment of likely importance in cytotoxic T cell recognition and graft rejection. Substitutions within this segment are spatially related by the helical turn. Variable residues usually lie in areas of high local hydrophilicity, and therefore they are probably on the surface of the molecule. The model predicts that they are frequently located in beta strands, beta-turns, or the above-mentioned alpha-helix, so that most substitutions would be accommodated within rigid frameworks that may impose structural constraints to variability. The secondary structure of alpha 1, alpha 2, and alpha 3 domains presents some analogies that suggest that they might share common features in their tertiary folding. The predicted structure of alpha 3 is strongly reminiscent of that of immunoglobulin constant domains. Possible arrangements of elements of secondary structure are discussed, as an attempt to situating the polymorphic regions of HLA class I antigens in a spatial context.

Amino Acid Sequence↗

PubMed2004

A twin study of sexual behavior in men.

The role of genetic and environmental influences on age of initiation of first sexual relations and engaging in sexual activity with multiple partners (10 or more partners in 1 year) was investigated in male twins (N = 6,744) from the Vietnam Era Twin Registry. Individual differences in both types of sexual behaviors were heritable, but only age of onset of sexual relations was significantly influenced by the environment shared by the twins. There was a moderate negative correlation between age of initiation of sexual relations and the multiple partners variable; initiating sexual relations earlier was associated with a higher probability of having multiple partners. The additive genetic influence on age of initiation also influenced the multiple partners variable. The substantial unique environmental influences on each variable were uncorrelated with each other. The data suggest that the observed association between age of initiation of sexual relations and having multiple partners is due to genetic influences common to both behaviors.

Adult↗

PubMedDate not supplied

Expression of the T-cell-specific gamma gene is unnecessary in T cells recognizing class II MHC determinants.

Subtractive complementary DNA cloning combined with partial protein sequencing has allowed identification of the genes encoding the alpha and beta subunits of T-cell receptors. The subtractive cDNA library prepared from the cytotoxic T lymphocyte (Tc) clone 2C has been found to contain a third type of clone encoding the gamma chain. The gamma gene shares several features with the alpha and beta genes: (1) assembly from gene segments resembling immunoglobulin V, J and C (respectively variable, joining and constant region) DNA segments; (2) rearrangement and expression in T cells and not in B cells; (3) sequences reminiscent of transmembrane and intracytoplasmic regions of integral membrane proteins; (4) a cysteine residue at the position expected for an interchain disulphide bond. The alpha and beta genes are expressed at equivalent levels in both Tc cells and helper T cells (TH). The gamma gene, obtained from 2C, has been found to be expressed in all Tc cells studied. Here we present evidence that strongly suggests that TH cells do not require gamma gene expression.

Animals↗

PubMed1997

Setting properties of alginate impression materials in dynamic viscoelasticity.

The viscoelastic properties of three alginate impression materials were investigated. A landmark of working time was calculated using a raw phase-time curve. A landmark of setting time was calculated from an inflection point of the divided difference of the first order in the share modulus-time curve. As a result, the working time was common at the point of delta = 45 degrees in variable frequencies. The mean value was obtained with less deviation. The setting times obtained were similar for variable frequencies. The mean values showed a distinct difference for each impression material.

Alginates↗

PubMed2002

Differential expression of p53 gene family members p63 and p73 in head and neck squamous tumorigenesis.

p73 and p63 are recently cloned genes that share considerable structural and functional homologies with the p53 tumor suppressor gene. These genes, unlike p53, express multiple mRNA isoforms with variable biologic functions, and their suppressor nature has yet to be confirmed. To determine the interrelationship between these genes in the tumorigenesis of head and neck squamous carcinoma (HNSC), we performed immunohistochemical analyses of their protein products and compared the data with clinicopathologic parameters in 38 patients. In histologically normal epithelium, p53 and p73 showed similar basal and/or parabasal expression, but that of p53 was weaker and discontinuous. p63 staining was noted in more suprabasal cellular layers and was stronger. In dysplasias, all three markers manifested variable but gradual increase in extent and intensity of cellular expression with histologic progression. In carcinomas, p63 was the most frequently expressed (94.7%), followed by p73 (68.4%) and p53 (52.6%). Significant statistical correlation was noted only between p63 and p73 expressions (P =.04). Although no statistical correlation was found between p53 and p63 or p73, p53-negative tumors overexpressed either p63 or p73. p73 expression was associated with distant metastasis and perineural/vascular invasion. Our study indicates that (1) p63 and p73 expression may represent an early event in HNSC tumorigenesis, (2) the lack of correlation between p73 or p63 and p53 expression suggests an independent and/or compensatory functional role, (3) p73 expression may play a part in HNSC progression, and (4) p73 and p63 may function as oncogenes in the development of these tumors.

Adult↗

PubMed2003

Retransplantation for recurrent hepatitis C: positive aspects.

1. The prevalence of retransplantation for hepatitis C (HCV) patients is stable (around 40%). 2. Survival models to predict outcome of retransplantation do not show that HCV is an independent variable with poor outcomes. 3. Using Model for End-Stage Liver Disease (MELD) scores from the United Network for Organ Sharing (UNOS) database from 1996-2002, retransplantation for HCV had similar outcomes to other causes of retransplantation. 4. Poorer outcomes were noted for retransplantation with MELD scores greater than 25. 5. Minimal survival thresholds need to be developed for retransplantation for all causes of retransplantation.

Graft Survival↗

PubMed1997

[Psychiatric disorders after political imprisonment in the Soviet occupation zone and in the GDR from 1945-1972].

In an exploratory study, 54 persons, were examined who were imprisoned--for at least six months--for political reasons first in the Soviet Occupation Zone and/or later in the German Democratic Republic (East Germany) between 1945 and 1972. Conditions of imprisonment included means that may be classified as psychological torture. Biographical data, experiences of imprisonment, factors helpful for coping, and influence of imprisonment on the persons' life were investigated in a semistructured interview. Symptoms were self-rated on a combined form of the von Zerssen Complaints List, psychiatric disorders were assessed in the computerised WHO composite International Diagnostic Interview. In 29 persons no psychiatric disorder was diagnosed. In 25 persons mostly anxiety disorders and depressive disorders were found. 21 of the latter reported that the onset of symptoms was during imprisonment or within a one-year period following it. Many persons had some symptoms of post traumatic stress disorder while only one fulfilled all criteria for diagnosing it. Only a few variables were significantly correlated with the severity of self-rated symptoms or with the existence of a psychiatric disorder. The shared variance was limited. Former prisoners with a better vocational integration had less often a psychiatric disorder and fewer symptoms. When interviewes stated some positive implications of imprisonment for their life thereafter and when they had more social contacts, this was also associated with a lower severity of self-rated symptoms.

Aged↗

PubMed2000

Scan statistics to scan markers for susceptibility genes.

Scan statistics are applied to combine information on multiple contiguous genetic markers used in a genome screen for susceptibility loci. This information may be, for example, allele sharing proportions for sib pairs or logarithm of odds (lod) scores in general small families. We focus on a dichotomous outcome variable, for example, case and control individuals or affected-affected versus affected-unaffected siblings, and suitable single-marker statistics. A significant scan statistic based on the single-marker statistics represents evidence of the presence of a susceptibility gene. For a given length of the scan statistic, we assess its significance by Monte Carlo permutation tests. Comparing P values for varying lengths of scan statistics, we treat the smallest observed P value as our statistic of interest and determine its overall significance level. We applied this method to a genome screen with autism families. The result was informative and surprising: A susceptibility region was found (genome-wide significance level, P = 0.038), which is missed with conventional approaches.

Alleles↗

PubMed2004

Recovery from sleep deprivation occurs during propofol anesthesia.

BACKGROUND: Some neurophysiologic similarities between sleep and anesthesia suggest that an anesthetized state may reverse effects of sleep deprivation. The effect of anesthesia on sleep homeostasis, however, is unknown. To test the hypothesis that recovery from sleep deprivation occurs during anesthesia, the authors followed 24 h of sleep deprivation in the rat with a 6-h period of either ad libitum sleep or propofol anesthesia, and compared subsequent sleep characteristics. METHODS: With animal care committee approval, electroencephalographic/electromyographic electrodes and intrajugular cannulae were implanted in 32 rats. After a 7-day recovery and 24-h baseline electroencephalographic/electromyographic recording period, rats were sleep deprived for 24 h by the disk-over-water method. Rats then underwent 6 h of either propofol anesthesia (n = 16) or ad libitum sleep with intralipid administration (n = 16), followed by electroencephalographic/electromyographic monitoring for 72 h. RESULTS: In control rats, increases above baseline in non-rapid eye movement sleep, rapid eye movement sleep, and non-rapid eye movement delta power persisted for 12 h after 24 h of sleep deprivation. Recovery from sleep deprivation in anesthetized rats was similar in timing to that of controls. No delayed rebound effects were observed in either group for 72 h after deprivation. CONCLUSION: These data show that a recovery process similar to that occurring during naturally occurring sleep also takes place during anesthesia and suggest that sleep and anesthesia share common regulatory mechanisms. Such interactions between sleep and anesthesia may allow anesthesiologists to better understand a potentially important source of variability in anesthetic action and raise the possibility that anesthetics may facilitate sleep in environments where sleep deprivation is common.

Anesthesia Recovery Period↗