Approaches to the treatment of high-risk thyroid cancer.
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Humans↗
Biomedical subjects
J Robbins
Publications and source records attributed to J Robbins.
Thyroid hormone binding to isolated human apolipoproteins A-II, C-I, C-II, and C-III: homology in thyroxine binding sites.
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Apolipoproteins↗
Self-reported causes of physical disability in older people: the Cardiovascular Health Study. CHS Collaborative Research Group.
OBJECTIVE: To determine the major conditions and symptoms reported to cause difficulty in 17 physical tasks of daily life and the criterion validity of self-report of diseases given as the causes of the difficulty in functioning, in community-dwelling older people. DESIGN: Cross sectional analyses of data obtained in an observational cohort study. SETTING: Research clinics in four US communities: Winston-Salem, NC, Hagerstown, MD, Pittsburgh, PA, and Sacramento, CA. PARTICIPANTS: 5201 community-dwelling people > or = 65 years old. RESULTS: Arthritis and other musculoskeletal diseases were given as the primary causes of difficulty in performing physical tasks by 49.0% of the participants reporting difficulty in any task, followed by heart disease (13.7%), injury (12.0%), old age (11.7%), lung disease (6.0%), and stroke (2.9%). The self-reports of diseases that caused disability varied by task. Whereas arthritis was given as a cause of difficulty in most of the 17 different tasks, heart and lung disease were more likely to be reported as causing difficulty with activities requiring high aerobic work capacity such as walking one-half mile or doing heavy housework. Stroke was more likely to be reported as causing difficulty with use of the upper extremities and in performing basic activities of daily living. There was a high degree of consistency (91%) between the diseases and symptoms reported to cause disabilities. The percentage of people who reported a disease as the cause of their difficulty performing a task and had independent confirmation of the diagnosis was 85% in men and 71% in women, and varied according to type of disease and the individual's cognitive status and health status. CONCLUSION: These data suggest that age-related chronic diseases are important causes of disability in older people but that the type of disability is dependent on the underlying disease that causes the disability. Also, self-report of the cause of disability appears to be generally accurate but is influenced by gender, health status, and type of disease.
Activities of Daily Living↗
Myosin heavy chain regulation and myocyte contractile depression after LV hypertrophy in aortic-banded mice.
Using an adult mouse aortic-banded model of pressure-overload hypertrophy and isolated cardiomyocyte mechanics studies, we examined the hypothesis that contractile depression is due to altered cardiac contractile proteins rather than changes in left ventricular (LV) geometry, loading, or the extracellular matrix. FVB mice were banded at the transverse aortic arch or sham operated and studied after 7 days. In nine animals the gradient across the aortic band averaged 47 +/- 4 mmHg. Compared with sham-operated controls, banded animals had increased LV weight-to-body weight ratio (2.8 +/- 0.1 and 3.5 +/- 0.1, respectively; P = 0.035). Left ventricles from additional age-matched groups of mice that underwent identical surgical procedures were examined for altered transcriptional control of myosin heavy chains (MHCs). beta-MHC protein content increased (15 +/- 2%) vs. shams (3.8 +/- 2%; P = 0.004). Dot blots of LV RNA showed a corresponding increase in beta-MHC transcripts in banded animals (15.8 +/- 2%) vs. controls (5.7 +/- 2%; P = 0.012). Contractile performance was assessed using enzymatically disaggregated isolated LV myocytes paced at 0.5 Hz. There was no difference in percentage myocyte shortening between banded (8.6 +/- 0.5%) and control (9.1 +/- 0.5%) animals. However, maximal velocity of contraction was depressed after aortic banding (129 +/- 11 vs. 233 +/- 28 microns/s; P = 0.007), as was velocity of relaxation (105 +/- 11 vs. 188 +/- 22 microns/s; P = 0.007). These results suggest that depressed myocyte contractility after induction of pressure-overload hypertrophy in aortic-banded mice may be, in part, a consequence of transcriptional upregulation of the beta-MHC.
Animals↗
Relation of smoking with carotid artery wall thickness and stenosis in older adults. The Cardiovascular Health Study. The Cardiovascular Health Study (CHS) Collaborative Research Group.
BACKGROUND: Cigarette smoking has been associated with increased risk of atherosclerotic diseases in hospital-based studies and in studies of middle-aged populations but not in population-based studies of older adults with and without clinical cardiovascular disease. METHODS AND RESULTS: We investigated the relation of smoking to carotid artery atherosclerotic disease, expressed as intimal-medial wall thickness and arterial lumen narrowing (stenosis) measured by ultrasound. Subjects were 5116 older adults participating in the baseline examination of the Cardiovascular Health Study, a community-based study of cardiovascular diseases in older age. With increased smoking there was significantly greater internal and common carotid wall thickening and internal carotid stenosis: current smokers > former smokers > never-smokers; for instance, the unadjusted percent stenosis was 24%, 20%, and 16%, respectively (P < .0001). A significant dose-response relation was seen with pack-years of smoking. These findings persisted after adjusting for other cardiovascular risk factors and were also confirmed when analyses were restricted to those without prevalent cardiovascular disease. The difference in internal carotid wall thickness between current smokers and nonsmokers was greater than the difference associated with 10 years of age among never-smoking participants (0.39 mm versus 0.31 mm). Among all participants, the prevalence of clinically significant (> or = 50%) internal carotid stenosis increased from 4.4% in never-smokers to 7.3% in former smokers to 9.5% in current smokers (P < .0001). CONCLUSIONS: These findings extend previous reports of a positive relation between smoking and carotid artery disease to a population-based sample of older adults using several different indicators of atherosclerotic disease.
Aged↗
Alpha-skeletal actin is associated with increased contractility in the mouse heart.
BALB/c mice express abnormally high levels of alpha-skeletal actin in the heart, which may be related to a duplication in the promoter of the alpha-cardiac actin gene. To evaluate the effects of overexpression of the alpha-skeletal actin isoform on cardiac contractile function, we studied these mice using the isolated perfused work-performing murine heart model and measured actin isoform expression in the same hearts. We quantified myocardial contractility from the maximum rate of contraction (+dP/dt) and time to peak pressure and relaxation from -dP/dt and time to half relaxation of left intraventricular pressure. Dot blots of total RNA hybridized against oligonucleotide sequences specific for either alpha-skeletal or alpha-cardiac actin mRNA showed that increased levels of alpha-skeletal actin RNA correlated significantly with increased contractility of hearts from the BALB/c mice (r = .80, n = 15, P < .001). The present study demonstrates a significant functional correlation between alpha-actin isoform content and cardiac contractile function and also that alpha-skeletal actin may promote an increased contractile function in the heart compared with alpha-cardiac actin.
Actins↗
What can physicians do to improve patient compliance?
The objective of this study was to determine the extent to which physicians are instructing patients about their medications. Using a telephone survey of approximately 2,000 adults, it was determined that whereas physicians are doing an excellent job in some areas of patient counseling on pharmaceuticals, they are lacking in other areas.
Data Collection↗
In vitro chamber specification during embryonic stem cell cardiogenesis. Expression of the ventricular myosin light chain-2 gene is independent of heart tube formation.
The molecular cues that control patterning of the heart tube during early cardiogenesis are largely unknown. The present study has explored the embryonic stem (ES) cell differentiation system to determine if this in vitro model could be useful in studying the process of regional specification of cardiac muscle cells at the earliest possible stages. As assessed by polymerase chain reaction, ribonuclease protection, in situ hybridization, and immunohistochemical analyses, ES cell differentiation into embryoid bodies is characterized by the transcriptional and translational activation of the ventricular regulatory (phosphorylatable) myosin light chain gene, demonstrating that ventricular specification occurs during ES cell cardiogenesis. The finding of a ventricular-specific marker in an in vitro system in the absence of an intact heart tube provides evidence for cardiac regional specification independent of positional cues or physiologic stimuli. The temporal expression of the myogenic regulatory factors, myogenin and MyoD, suggests activation of the skeletal muscle program following cardiac myogenesis in vitro, indicating temporal fidelity to the progression of in vivo myogenesis. These data establish the mouse embryonic stem cell system as a model for cardiac chamber specification and suggest a promising approach in the study of regional specification in genetically engineered cardiac muscle cells.
Animals↗
Carboxy-terminal processing of the large subunit of [NiFe] hydrogenases.
Two electrophoretic forms of the large subunit of the soluble periplasmic [NiFe] hydrogenase from Desulfovibrio gigas have been detected by Western analysis. The faster moving form co-migrates with the large subunit from purified, active enzyme. Amino acid sequence and composition of the C-terminal tryptic peptide of the large subunit from purified hydrogenase revealed that it is 15 amino acids shorter than that predicted by the nucleotide sequence. Processing of the nascent large subunit occurs by C-terminal cleavage between His536 and Val537, residues which are highly conserved among [NiFe] hydrogenases. Mutagenesis of the analogous residues, His582 and Val583, in the E. coli hydrogenase-1 (HYD1) large subunit resulted in significant decrease in processing and HYD1 activity.
Amino Acid Sequence↗
Coupling of m2 and m4 muscarinic acetylcholine receptor subtypes to Ca(2+)-dependent K+ channels in transformed NL308 neuroblastoma x fibroblast hybrid cells.
Muscarinic acetylcholine receptor (mAChR) subtype (m1-m4)-specific cDNAs were transfected into NL308 neuroblastoma-fibroblast hybrid cells and clones expressing each of the individual mAChR subtypes m1, m2, m3 and m4 obtained. Acetylcholine increased phosphoinositide (PI) turnover in m1- and m3-transformed cells, but did not produce detectable changes in m2- and m4-transformed cells. In cells expressing m1 and m3 subtypes, ACh produced an initial outward K+ current, followed by a cationic current. In cells expressing m2 and m4 receptors, only the initial K+ current was detected. The outward currents were associated with a rise in intracellular Ca2+ as measured with Fura-2 or Indo-1, and were inhibited by chelating intracellular Ca2+ with external BAPTA-AM, or by external charybdotoxin or Ba2+: hence they were attributed to the activation of a Ca(2+)-dependent K+ current. However, the outward current produced in m2- and m4-transformed cells was blocked by pretreatment with 5 ng ml-1 Pertussis toxin (PTX), whereas that in m1- and m3-transformed cells was not. These results suggest that m2- and m4-receptors in transformed NL308 cells coupled to PTX-sensitive G-protein which is capable of mobilizing intracellular Ca2+ and activate IK(Ca), whereas m1 and m3 receptors activate a similar process through a different, PTX-insensitive G-protein.
Acetylcholine↗
Role of myocyte-specific enhancer-binding factor (MEF-2) in transcriptional regulation of the alpha-cardiac myosin heavy chain gene.
The intergenic region between the mouse alpha-cardiac myosin heavy chain and beta-myosin heavy chain genes has previously been shown to direct expression of the bacterial chloramphenicol acetyltransferase reporter gene in transgenic mice in a tissue-specific manner. Sequence analyses located a putative myocyte-specific enhancer-binding factor (MEF-2) site situated in the regulatory region of this gene proximal to the start site of transcription. The role of this element in directing the cardiac compartment-specific expression of the transgene was assessed. The polymerase chain reaction was used to perform substitution mutagenesis of the MEF-2 binding site, and lack of MEF-2 binding was confirmed by gel retardation assays. The resultant construct was used to generate transgenic mice. Surprisingly, transgene expression was not down-regulated, but was significantly increased in the hearts of the MEF-2 mutant mice. In addition, cardiac-specific expression of the transgene was perturbed with significant levels of ectopic expression occurring in the aorta.
Animals↗
In vivo analysis of the murine beta-myosin heavy chain gene promoter.
The 5' upstream region of the murine beta-myosin heavy chain (MHC) gene has been isolated and tested for its ability to drive gene expression in transgenic mice. Three classes of transgenic mice were generated. The constructs contained approximately 5000, 2500, and 600 base pairs of beta-MHC upstream sequence fused to the chloramphenicol acetyltransferase gene and were termed beta 5, beta 2.5, and beta .6, respectively. Muscle-specific expression was observed with all three constructs. However, only the beta 5 lines directed high levels of muscle-specific transgene expression in both pre- and postbirth mice. Expression driven by the two shorter constructs was two to three orders of magnitude lower when the chloramphenicol acetyltransferase specific activities were compared. These data suggest that a distal-positive element directs high levels of gene expression in the ventricle and in slow skeletal muscles. Analyses of transgene expression during heart maturation revealed that some of the beta 5 lines were not able to respond in an appropriate manner to developmental transcriptional cues. Unlike the endogenous beta-MHC gene, which is down regulated in the ventricles around the time of birth, reporter gene expression in the majority of the lines generated was not shut off in the ventricles of the adult animals. These data indicate that high levels of muscle-specific beta-MHC gene expression are dependent upon the combinatorial interactions of a number of sequence elements that are distributed over a large region of the gene's upstream sequence.
Aging↗
Mapping of the chicken N-CAM gene and a myosin heavy chain gene: avian microchromosomes are not genetically inert reserves of DNA.
Physical mapping of the chicken neural cell adhesion molecule gene and of a chicken myosin fast-white heavy chain gene via in situ hybridization has assigned both loci to different-sized microchromosomes in this species. Two genomic cloned chicken DNA probes of 16 kb (lambda cN6) and 15 kb (DCM 11), respectively, were biotin labeled for fluorescent detection of the genes. The implications derived from these results, together with further data just now beginning to accumulate regarding the genetic content of avian microchromosomes, confirm an unexpectedly active role for these minute chromosomes.
Animals↗
Transgenic analysis of the thyroid-responsive elements in the alpha-cardiac myosin heavy chain gene promoter.
The role of two putative, cis-acting thyroid hormone-responsive elements, TRE1 and TRE2, located at -129 to -149 and -102 to -120, respectively, on the murine alpha-myosin heavy chain (MHC) gene, has been investigated in transgenic mice. These motifs are present in a 4.5-kilobase fragment lying upstream of the transcriptional start site of the mouse alpha-MHC gene: this fragment directs appropriate expression of a reporter gene in transgenic mice (Subramaniam, A., Jones, W. K., Gulick, J., Wert, S., Neumann, J., and Robbins, J. (1991) J. Biol. Chem. 266, 24613-24620). Here, we independently mutate the TRE1 and TRE2 elements by base substitution. The mice were analyzed for transgene expression in different muscle and non-muscle tissues including the atria and ventricles. Normal levels of transgene expression were observed in euthyroid mice carrying a mutation in TRE1. In contrast to these results, mice in which TRE2 was mutated showed reduced levels of CAT activity in both the atria and ventricles, suggesting a previously undefined role for this element in the constitutive up-regulation of the alpha-MHC gene. In hypothyroid mice carrying either of these mutations, the complete cessation of ventricular expression of the chloramphenicol acetyltransferase transcripts that takes place in the alpha-5.5 (wild type) animals did not occur.
Animals↗
In vitro production of enzymatically active myosin heavy chain.
In order to initiate studies on the structural and functional relationships of the myosin heavy chain, we constructed a full-length complementary DNA encoding the isoform that is found in the fast white muscle of the embryonic chicken. The complementary DNA contained 108 basepairs of its 3'-untranslated region and was preceded by a leader sequence derived from the alfalfa mosaic virus. Similarly, a complementary DNA encoding 963 amino acids which encompass the subfragment-1 of myosin and part of the subfragment-2 was also constructed. Each was inserted into the expression vector pMT2 and transiently transfected into COS-1 cells. Both constructs directed the expression of the respective proteins, each of which was immunogenic. The full-length and subfragment-1 proteins interacted with actin and demonstrated high levels of a K(+)-activated, EDTA-resistant ATPase activity, which is characteristic of myosin.
Animals↗
Whole-cell recording of neuroblastoma x glioma cells during downregulation of a major substrate, 80K/MARCKS, of protein kinase C.
Differentiated neuroblastoma cells exhibit both the delayed rectifier potassium current (IK) and the M-current (IM). The present study was designed to determine the roles of protein kinase C (PKC) and of the calmodulin-binding protein 80K/MARCKS, a prominent substrate for PKC and possible regulator of these currents. Neuroblastoma x glioma (NG108-15) hybrid cells transfected with m1 muscarinic receptors were grown with 1% fetal bovine serum (FBS) without the prostaglandin E1 (PGE1) and isobutylmethylxanthine (IBMX) usually added in preparation for electrophysiological studies. Under these conditions, the usual pleomorphism was largely abolished, leaving two populations of small cells with stellate and spherically symmetrical geometries. Whole-cell patch clamping indicated that the two cell types had identical electrophysiological properties, displaying: IK, a small current through a "T-like" Ca2+ channel, and no M-current. Stimulation with carbachol shifted the distribution of cells to a more stellate morphology within 24 hr and later (after 48 hr) reduced the PKC substrate 80K/MARCKS by 22 +/- 7%. In contrast to the stimulation of IK observed with cardiac cells, PKC activation produced only a small inhibition of IK, which was independent of carbachol pretreatment. Thus, PKC and 80K/MARCKS can be dissociated from the regulation of IK in neuroblastoma cells.
Animals↗
Agonist-induced inhibition of inositol-trisphosphate-activated IK(Ca) in NG108-15 neuroblastoma hybrid cells.
IK(Ca) activated by intracellular ionophoresis of inositol trisphosphate (IP3) or pressure-applied acetylcholine was inhibited by bradykinin and acetylcholine in NG108-15 cells transfected with m1 receptors. The inhibition of the IP3-evoked current was complete at 10 microM acetylcholine. This inhibition was not seen if the current was evoked by intracellular ionophoresis of calcium ions. Only receptors the activate the phosphoinositide system in these cells produced this inhibition, i.e. transfected muscarinic m1 and m3 and bradykinin receptors, but not muscarinic m2, m4 or adrenergic alpha 2 receptors. This inhibition was not sensitive to pertussis toxin or staurosporine. The concentrations of acetylcholine needed to inhibit the evoked current were identical to those needed to raise intracellular calcium but tenfold less than those needed for the agonist to activate IK(Ca). In a normal calcium-containing superfusate, recovery from inhibition required around 8 min (half-time 4 min) after removal of acetylcholine. When the experiment was performed in calcium-free medium no recovery was seen after 8 min washing in drug-free solution, but complete recovery was seen within 3 min (half-time 1.5 min) after adding calcium. Responses to repeated pressure applications of acetylcholine could be reversibly inhibited by acetylcholine and bradykinin. It seems, then, that there is no direct action of acetylcholine or bradykinin on the IK(Ca) channels themselves but that concentrations below those needed to activate IK(Ca) can empty and inhibit the IP3-sensitive calcium store. This may provide a mechanism for heterologous desensitization for phospholipase-C-linked receptor-mediated responses.
Acetylcholine↗
Swallowing after unilateral stroke of the cerebral cortex.
We report differential patterns of swallowing in 40 patients with their first ischemic middle cerebral artery (MCA) stroke and compare these to 20 nonstroke controls. Stroke patients were divided a priori, into groups by right or left and, post hoc, primarily anterior or posterior MCA territory lesions. The left hemisphere subgroup was differentiated from controls by longer pharyngeal transit durations and from the right hemisphere group by shorter pharyngeal response durations. The right hemisphere subgroup was characterized by longer pharyngeal stage durations and higher incidences of laryngeal penetration and aspiration of liquid. Anterior lesion subjects demonstrated significantly longer swallowing durations on most variables compared to both normal and posterior lesion subjects. Changes in the consistency of foods and other modifications for safe nutrition should be considered during the first month of recovery for unilateral stroke patients with swallowing difficulty.
Adult↗