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PubMed1990

Muscle fatigue in McArdle's disease. Muscle fibre conduction velocity and surface EMG frequency spectrum during ischaemic exercise.

The origin of fatigue in McArdle's disease is still a matter of debate. Both a reduction of muscle membrane excitability and failure of excitation-contraction (E-C) coupling have been suggested as causes. We performed intermittent isometric biceps brachii contractions (80% maximal voluntary contraction, rate 30/min) under local ischaemia in 5 McArdle's disease patients and 26 healthy controls. Our results show that in McArdle's disease the exerted force is less, the surface EMG (SEMG) amplitude steadily increases, and that the power density spectrum (PDS) shifts to lower frequencies, the latter without significant differences when compared with normals. The most important finding is that muscle membrane excitability remains unimpaired during ischaemic exercise, establishing a dominant role for intramuscular lactic acid formation in the reduction of muscle fibre conduction velocity seen in normal subjects. As is indicated by the shift of the PDS towards lower frequencies, as well as by the increase in SEMG amplitude, it can be concluded that during ischaemic exercise in patients with myophosphorylase deficiency, fatigue occurs without alterations in muscle membrane excitability and is due to a failure of E-C coupling.

Adolescent↗

PubMed1988

Induction by growth factors from platelets of the focus-forming transformed phenotype in carcinogen-treated C3H/10T1/2 fibroblasts.

Wounding of mouse skin promotes tumor formation as effectively as 12-O-tetradecanoylphorbol-13-acetate (TPA). Like wounding, TPA stimulates the release of growth factors from platelets and the leakage of plasma from the capillary circulation. Thus, initiated cells in TPA-treated skin are also exposed to the components of whole blood-derived serum. It is possible that serum factors play an important role in the multi-step process of neoplastic transformation. In this study, we evaluate the significance of serum components derived from plasma and platelets in the neoplastic transformation of C3H/10T1/2 mouse fibroblasts exposed to methylcholanthrene. Carcinogen-treated cultures grown to confluence in medium containing 5% whole blood-derived serum (FBS), but maintained for 5 weeks after confluence in plasma-derived serum (PDS), which lacks the platelet components found in whole blood-derived serum, failed to produce transformed foci. The addition of an aqueous extract of platelets to PDS induced the formation of transformed foci with an efficiency comparable to FBS and proportional to the amount and mitogenic activity of the platelet extract. The growth of newly transformed cells was not inhibited by the absence of platelet factors in the culture medium. The loss of density-dependent growth control required at least 3-4 weeks of post-confluence exposure to serum factors derived from platelets. The data suggest that platelet factors induce the conversion of a carcinogen-initiated cell to a focus-forming transformed cell. We demonstrate that platelet-derived growth factor (PDGF) is essential for the induction of the focus-forming phenotype in initiated cells and that PDGF acts co-operatively with the platelet-derived type-beta transforming growth factor and EGF-like growth factor to induce this transformed phenotype. These growth factors may be acting as endogenous promoters of neoplastic transformation of chemically initiated C3H/10T1/2 mouse fibroblasts.

Animals↗

PubMed1997

Nucleosome structure and positioning modulate nucleotide excision repair in the non-transcribed strand of an active gene.

Nucleotide excision repair (NER) is a major pathway to remove pyrimidine dimers (PDs), a class of DNA lesions generated by ultraviolet light. Since folding of DNA into nucleosomes restricts its accessibility and since transcription and DNA repair require access to DNA, nucleosome structure and positioning as well as the transcriptional state may affect DNA repair. We recently determined the chromatin structure of the yeast URA3 gene at high resolution and found multiple positions of nucleosomes as well as strand- and site-specific variation in DNA accessibility to DNase I (internal protected regions). Here, the same high-resolution primer extension technique was used to investigate NER of PDs in the URA3 gene of a mini-chromosome in vivo. In the non-transcribed strand (NTS), fast repair correlates with PD locations in linker DNA and towards the 5' end of a positioned nucleosome. Slow repair correlates with the internal protected region of the nucleosome. This repair heterogeneity reflects a modulation of NER by positioned nucleosomes in the NTS. NER in the transcribed strand (TS) is fast, less heterogeneous and shows no correlation with chromatin structure. Apparently, transcription-coupled repair overrides chromatin modulation of NER in the TS. Heterogeneity in NER generated by chromatin structure on the NTS may contribute to heterogeneity in mutagenesis.

Aldose-Ketose Isomerases↗

PubMed2000

Saccharomyces cerevisiae Ras/cAMP pathway controls post-diauxic shift element-dependent transcription through the zinc finger protein Gis1.

The Saccharomyces cerevisiae protein kinase Rim15 was identified previously as a component of the Ras/cAMP pathway acting immediately downstream of cAMP-dependent protein kinase (cAPK) to control a broad range of adaptations in response to nutrient limitation. Here, we show that the zinc finger protein Gis1 acts as a dosage-dependent suppressor of the rim15Delta defect in nutrient limitation-induced transcriptional derepression of SSA3. Loss of Gis1 results in a defect in transcriptional derepression upon nutrient limitation of various genes that are negatively regulated by the Ras/cAMP pathway (e.g. SSA3, HSP12 and HSP26). Tests of epistasis as well as transcriptional analyses of Gis1-dependent expression indicate that Gis1 acts in this pathway downstream of Rim15 to mediate transcription from the previously identified post-diauxic shift (PDS) element. Accordingly, deletion of GIS1 partially suppresses, and overexpression of GIS1 exacerbates the growth defect of mutant cells that are compromised for cAPK activity. Moreover, PDS element-driven expression, which is negatively regulated by the Ras/cAMP pathway and which is induced upon nutrient limitation, is almost entirely dependent on the presence of Gis1.

Bacterial Proteins↗

PubMed1984

Response of malignant mammary cell lines to a growth inhibitor partially purified from plasma-derived human serum.

The specificity and mode of action of a growth inhibitory factor (GIF) isolated from human plasma-derived serum (PDS) was examined with cell lines established from malignant and nonmalignant human tissues. The mammary cell line, MCF-7, was used in previous work to monitor purification of GIF from serum. The current study showed that, of 9 mammary cell lines, 5 (MDA-MB-415, BT-474, MCF-7, T47D, ZR-75) were inhibited by GIF partially purified from a single serum source. The degree of cell line sensitivity to DEAE-purified GIF was directly related to the amount of inhibition observed with unfractionated PDS. The growth of cells established from other malignancies (lung, colon, melanoma, cervix) and normal diploid fibroblasts was not inhibited. MCF-7 cell growth inhibition was fully reversible following 3 days incubation in GIF but was not reversible after 5 days. Inhibition represented a cytostatic effect. Among the macromolecular synthetic events assayed, DNA and RNA remained unaffected by GIF whereas protein synthesis per cell was markedly elevated. Fluorescence-activated cell sorter analysis of treated and control populations showed no differences in G1, S-, and G2 phase distributions.

Blood Proteins↗

PubMed2005

Ethylene regulation of carotenoid accumulation and carotenogenic gene expression in colour-contrasted apricot varieties (Prunus armeniaca).

In order to elucidate the regulation mechanisms of carotenoid biosynthesis in apricot fruit (Prunus armeniaca), carotenoid content and carotenogenic gene expression were analysed as a function of ethylene production in two colour-contrasted apricot varieties. Fruits from Goldrich (GO) were orange, while Moniqui (MO) fruits were white. Biochemical analysis showed that GO accumulated precursors of the uncoloured carotenoids, phytoene and phytofluene, and the coloured carotenoid, beta-carotene, while Moniqui (MO) fruits only accumulated phytoene and phytofluene but no beta-carotene. Physiological analysis showed that ethylene production was clearly weaker in GO than in MO. Carotenogenic gene expression (Psy-1, Pds, and Zds) and carotenoid accumulation were measured with respect to ethylene production which is initiated in mature green fruits at the onset of the climacteric stage or following exo-ethylene or ethylene-receptor inhibitor (1-MCP) treatments. Results showed (i) systematically stronger expression of carotenogenic genes in white than in orange fruits, even for the Zds gene involved in beta-carotene synthesis that is undetectable in MO fruits, (ii) ethylene-induction of Psy-1 and Pds gene expression and the corresponding product accumulation, (iii) Zds gene expression and beta-carotene production independent of ethylene. The different results obtained at physiological, biochemical, and molecular levels revealed the complex regulation of carotenoid biosynthesis in apricots and led to suggestions regarding some possible ways to regulate it.

Carotenoids↗

PubMed2006

Immortalization of normal human cytotrophoblast cells by reconstitution of telomeric reverse transcriptase activity.

Placental trophoblast cells are unique endocrine cells that play vital roles during the processes of embryonic implantation and placentation. However, research into the function of human trophoblast has been largely restrained mainly due to a lack of adequate cell models. A normal placenta-origin cytotrophoblast cell line (NPC) was previously established by our group, but these cells showed replicating senescence after 50 population doublings (PDs). In this study, the human telomerase catalytic subunit gene (htert) was transferred into B6 strain of NPC cells, and strains with reconstituted telomerase activity (B6Tert) were established. It was shown that B6Tert-1 cells produce various biomarkers of normal extravillous cytotrophoblasts during the early weeks of gestation. Meanwhile, the cell invasiveness was inhibited by transforming growth factor beta (TGFbeta). However, their ability to form syncytium was relatively low when stimulated with fetal calf serum (FCS). The cells maintained normal cell growth properties and failed to elicit tumours in nude mice. They proliferated continuously with no signs of senescence until the final count at 210 PDs. The growth rate of B6Tert-1 cells was increased when compared with the parental cells, which results, at least partly, from facilitating release of the G1/S checkpoint during the cell-cycle regulation. This is the first report of immortalizing human normal cytotrophoblast (CTB) cells by activation of telomerase activity. The cells will provide an ideal in vitro model for the study of human extravillous trophoblast (EVT) functions and consequently the mechanisms of embryonic implantation and placentation.

Animals↗

PubMed1997

Expression of functional elements inserted into the 35S promoter region of infectious cauliflower mosaic virus replicons.

We describe experiments directed towards development of cauliflower mosaic virus (CaMV) replicons for propagation of functional elements during infection of plants. Modifications and inserts were introduced into replaceable domains associated with the 35S promoter. The 35S enhancer (-208 to -56) was found to potentiate promoter activity when in reverse orientation sufficient to establish systemic infection. However, replacement of the 35S enhancer with that from the nos promoter caused loss of infectivity. A 31 bp oligonucleotide containing a polypurine tract specifying initiation of CaMV plus strand DNA synthesis was inserted into a 35S enhancer deletion mutant and propagated in plants. Analysis of progeny DNA showed the presence of an additional discontinuity at its new location in the 35S enhancer, indicating that the artificial primer had functioned correctly in an ectopic site. An intron and flanking sequences from the RNA leader of the Arabidopsis phytoene desaturase (pds) gene, when inserted into the 35S enhancer in forward orientation was very efficiently spliced during infection. The CaMV replicon carrying the pds gene fragment produced unusual infection characteristics, with plants showing early symptoms and then recovering. We conclude that infectious CaMV replicons can be used to carry a variety of elements that target both viral and host functions.

Arabidopsis↗

PubMed2005

Discrimination of single nucleotide polymorphisms by strand exchange assay using partially double-stranded probes.

Previously we designed the partially double-stranded (PDS) probes that have protruding single-stranded portion for a single-base mismatch analysis. The single-stranded portion is engineered to sense existences of mismatches in the counterparts and to transduce it in strand exchange rates. Here we report the influence of probe length and operating conditions, such as temperature and buffer conditions, on the mismatch resolution using the PDS probes. Reliable detection of single-base mismatches was achieved even with a 45mer-long probe. By lowering operating temperature, the higher and faster discrimination of the mismatches was demonstrated. Addition of cationic comb-type copolymers (CCCs) in the buffer increased the reaction rate 3-4 orders without disordering the resolving power.

Base Pair Mismatch↗

PubMed2000

The design of the prenatal determinants of schizophrenia study.

This paper describes the Prenatal Determinants of Schizophrenia (PDS) Study; three companion papers report the first results. The PDS Study was designed to study early antecedents of schizophrenia in a birth cohort of 1959-1967 for whom a wealth of archived prenatal data--including maternal sera--was available. Making use of the registries of a health plan into which the cohort was born, we ascertained and then diagnosed 71 cases of schizophrenia and spectrum disorders in the cohort. We describe herein the available prenatal data, the process of case diagnosis, and the strategies used to analyze prenatal determinants of schizophrenia in this cohort. Data are presented that bear on the main sources of potential bias and are important to understanding the strengths and limitations of this unique data set.

Adult↗

PubMed2000

Maternal exposure to respiratory infections and adult schizophrenia spectrum disorders: a prospective birth cohort study.

We sought to examine the relationship between maternal exposure to adult respiratory infections and schizophrenia spectrum disorder (SSD) in the Prenatal Determinants of Schizophrenia (PDS) Study, a large birth cohort investigation. Previous work suggests that second trimester exposure to respiratory infection may be a risk factor for SSD. We therefore examined whether this class of infection was associated with adult SSD. For this purpose, we capitalized on several design advantages of the PDS Study, including a comprehensive, prospective data base on physician-diagnosed infections and a continuous followup in which diagnoses of SSD were made, in the majority, by face-to-face interview. Second trimester exposure to respiratory infections was associated with a significantly increased risk of SSD, adjusting for maternal smoking, education, and race (rate ratio [RR] = 2.13 [1.05-4.35], chi2 = 4.36, df= 1,p = 0.04); no associations were shown for first trimester and third trimester exposure to these respiratory infections. These findings support-and extend-previous studies suggesting that second trimester respiratory infections are risk factors for SSD. This study therefore has implications toward uncovering the etiology of schizophrenia and developing preventive strategies.

Adult↗

PubMed2000

Incidence and cumulative risk of treated schizophrenia in the prenatal determinants of schizophrenia study.

The present study uses data from the Prenatal Determinants of Schizophrenia (PDS) Study to derive age- and sex-specific estimates of incidence and cumulative risk for DSM-IV schizophrenia. Although not designed as an incidence study, the PDS Study uses both a well-defined population under continuous followup and DSM-IV diagnoses. The originating cohort was established in Alameda County, California, during 1959-1967 and yielded 12,094 cohort members followed from 1981 to 1997 during the principal ages at risk for schizophrenia. Survival analytic techniques showed that schizophrenia incidence rates per 10,000 person-years for men were 9.4 for ages 15-19; 5.6 for ages 20-24; 3.3 for ages 25-29; and 0.9 for ages 30-34. Schizophrenia incidence rates per 10,000 person-years for women were 1.6 for ages 15-19; 1.3 for ages 20-24; and 4.1 for ages 25-29. The cumulative risk for schizophrenia by age 38 was 0.93 percent for men and 0.35 percent for women. These estimates of incidence rates and risk were higher than those in traditional incidence studies but similar to recent findings in other cohorts. Possible explanations for the apparently high rates of disorder include chance, design effects, and true variation in risk over time and place.

Adolescent↗

PubMed1992

Serum masks the inhibition of thrombin-induced prostacyclin release produced by anticardiolipin antibodies.

The effect on thrombin-induced release of prostacyclin from human umbilical vein endothelial cells of preincubation with both serum and serum derived from platelet-poor plasma (PDS) from patients with systemic lupus erythematosus (SLE), systemic sclerosis, the antiphospholipid syndrome (APS) and normal controls was examined. Although no significant differences in thrombin-induced prostacyclin release were found in any of the patient groups, further analysis revealed that PDS from patients with SLE and APS that contained IgG anticardiolipin antibodies produced significant inhibition of prostacyclin release when compared with controls (P = 0.02). The effect was maximal with samples that contained both IgG and IgM anticardiolipin antibodies (P less than 0.01) and which had a significantly higher titre of IgG antibodies than samples which contained solely IgG antibodies (P less than 0.05). The absence of any corresponding inhibition of prostacyclin release by serum samples that contained anticardiolipin antibodies, possibly due to the release of masking stimulatory factors by platelets during coagulation, provides an explanation for the conflicting nature of previous reports.

Adult↗

PubMed2001

Effect of fibroblast donor cell age and cell cycle on development of bovine nuclear transfer embryos in vitro.

The effects of cell cycle stage and the age of the cell donor animal on in vitro development of bovine nuclear transfer embryos were investigated. Cultures of primary bovine fibroblasts were established from animals of various ages, and the in vitro life span of these cell lines was analyzed. Fibroblasts from both fetuses and calves had similar in vitro life spans of approximately 30 population doublings (PDs) compared with 20 PDs in fibroblasts obtained from adult animals. When fibroblasts from both fetuses and adult animals were cultured as a population, the percentage of cells in G1 increased linearly with time, whereas the percentage of S-phase cells decreased proportionately. Furthermore, the percentage of cells in G1 at a given time was higher in adult fibroblasts than in fetal fibroblasts. To study the individual cells from a population, a shake-off method was developed to isolate cells in G1 stage of the cell cycle and evaluate the cell cycle characteristics of both fetal and adult fibroblasts from either 25% or 100% confluent cultures. Irrespective of the age, the mean cell cycle length in isolated cells was shorter (9.6-15.5 h) than that observed for cells cultured as a population. Likewise, the length of the G1 stage in these isolated cells, as indicated by 5-bromo-deoxyuridine labeling, lasted only about 2-3 h. There were no differences in either the number of cells in blastocysts or the percentage of blastocysts between the embryos reconstructed with G1 cells from 25% or 100% confluent cultures of fetal or adult cell lines. This study suggests that there are substantial differences in cell cycle characteristics in cells derived from animals of different ages or cultured at different levels of confluence. However, these factors had no effect on in vitro development of nuclear transfer embryos.

Aging↗

PubMed1989

Child psychiatry program directors' ratings of residency experiences.

Child and adolescent psychiatry program directors' (PDs) were asked to complete survey forms to rate the importance of required residency experiences and express views on length of training. There was a 93% return rate of questionnaires sent to the 129 academic programs represented in the Society of Professors of Child and Adolescent Psychiatry. The majority of PDs favor the status quo and do not want to add or subtract from the present requirements. Experiences most favored were those with older children, adolescents, and parents, and those in the use of psychopharmacology. Least favored experiences were with cognitive therapy, research, psychological testing, and teaching. There was little interest in eliminating the internship year or residency time with adults.

Adolescent Psychiatry↗

PubMed1997

Axis II psychopathology as a function of Axis I disorders in childhood and adolescence.

OBJECTIVE: To examine the occurrence of elevated personality disorder (PD) dimensional scores in a community sample of young adults as a function of the occurrence of Axis I disorders through age 18 years. METHOD: 299 individuals who had been interviewed regarding Axis I disorders twice while in adolescence (first when 14 through 18 years of age) were carefully assessed regarding Axis I and II psychopathology at age 24. RESULTS: The prevalence of PD diagnoses was relatively low (3.8% in participants with a history of Axis I versus 1.7% in participants with no Axis I history). The occurrence of all four Axis I diagnostic categories (major depression, anxiety disorders, disruptive behavior disorders, substance use disorders) in childhood and adolescence was associated with elevated PD dimensional scores. The likelihood of elevated PD dimensional scores increased as a function of the number of Axis I disorders. Elevated PD scores were significantly associated with a negative course of major depression. CONCLUSIONS: Although the rates of PDs were low, the findings suggest a substantial degree of association between early-onset Axis I disorders and Axis II psychopathology in young adulthood. More research is needed to develop assessment and treatment recommendations addressing the early manifestations of PDs.

Adolescent↗

PubMed2001

A pilot study of defenses in adults with personality disorders entering psychotherapy.

This study examined defensive functioning in adults entering open-ended dynamic psychotherapy and determined whether defenses predict retention at 1 year. Beginning at about the fifth session, 14 adults with personality and or depressive disorders entering open-ended dynamic psychotherapy had five therapy sessions audiotaped. The sessions were rated according to the Defense Mechanism Rating Scales, quantitative method. Interrater reliability of overall defensive functioning (ODF) and the number of defenses used per session were intraclass R = .85 and .83, respectively, whereas that of seven defense levels yielded a median of .625 (range .52 to .80). Stability of ODF across the five sessions was intraclass R = .48. The 11 subjects with personality disorders (PDs) used predominantly lower immature (49.3%) and neurotic (40.8%) level defenses. Subjects with borderline PD had significantly lower ODF than those with other PD types. Higher ODF was associated with remaining in treatment at 1 year, although this was confounded with a higher frequency of weekly sessions. Quantitative assessment of defenses demonstrated fair to excellent reliability and indicated that in the short term approximately half of defensive functioning reflects a stable repertoire, whereas the remaining variation may be due to occasion and error. PDs and especially BPD are characterized by a predominance of lower defenses. Higher defensive functioning was associated with twice-weekly sessions and retention in therapy at 1 year. In therapy, adjusting technique to the patient's defenses may improve retention and outcome.

Adolescent↗

PubMedDate not supplied

Factors associated with psychotropic drug usage among nursing home residents with dementia.

BACKGROUND: Although federal regulations hold nursing homes responsible for monitoring psychotropic drug (PD) usage, there is a high prevalence of PD usage and significant variation in use across nursing homes. OBJECTIVES: The aims of study were to (a) describe current PD usage in nursing homes and (b) examine resident and nursing home factors associated with PD usage in nursing home residents with dementia. METHODS: A multivariate, multisite, cross-sectional descriptive study was used on data from 107 dementia patients residing in nine randomly selected nursing homes in southeastern Michigan. The PD usage of interest included antipsychotics, antidepressants, anxiolytics or sedatives, and mood stabilizers. Regression analysis tested resident factors, including cognitive ability, functional ability, presence of depressive symptoms, and demographic characteristics, and three facility factors (nursing home size, type of ownership, and level of registered nurse [RN] staffing) in comparison with PD usage. RESULTS: In this study, 67.3% of the participants received at least one PD. The most frequently prescribed PDs were antidepressants (41.1%) and antipsychotics (37.4%). Newly developed antipsychotics such as risperidone were given more frequently to residents than were conventional drugs such as haloperidol. Regression analysis suggests that the presence of depressive symptoms (odds ratio [OR]= 3.5, p < .01) and low levels of RN staffing (OR = 1.0, p < .01) were associated with the use of PD. DISCUSSION: Psychotropic drugs are prescribed frequently for nursing home residents, although such usage is variable. Behavioral symptoms were not an independent predictive factor for PD use. Rather, combined resident and facility characteristics best predicted the use of PDs in nursing home residents. The evaluation of nursing home systems for these characteristics as predictive factors for PD usage in nursing home patients with dementia is suggested by the results. Likewise, attention to new drugs such as selective serotonin reuptake inhibitors and their appropriate use is recommended.

Aged↗