Peroxisome proliferator-activated receptor gamma coactivator-1 promotes cardiac mitochondrial biogenesis

Cardiac mitochondrial function is altered in a variety of inherited and acquired cardiovascular diseases. Recent studies have identified the transcriptional coactivator peroxisome proliferator-activated receptor gamma coactivator-1 (PGC-1) as a regulator of mitochondrial function in tissues specialized for thermogenesis, such as brown adipose. We sought to determine whether PGC-1 controlled mitochondrial biogenesis and energy-producing capacity in the heart, a tissue specialized for high-capacity ATP production. We found that PGC-1 gene expression is induced in the mouse heart after birth and in response to short-term fasting, conditions known to increase cardiac mitochondrial energy production. Forced expression of PGC-1 in cardiac myocytes in culture induced the expression of nuclear and mitochondrial genes involved in multiple mitochondrial energy-transduction/energy-production pathways, increased cellular mitochondrial number, and stimulated coupled respiration. Cardiac-specific overexpression of PGC-1 in transgenic mice resulted in uncontrolled mitochondrial proliferation in cardiac myocytes leading to loss of sarcomeric structure and a dilated cardiomyopathy. These results identify PGC-1 as a critical regulatory molecule in the control of cardiac mitochondrial number and function in response to energy demands.

Restoration of insulin-sensitive glucose transporter (GLUT4) gene expression in muscle cells by the transcriptional coactivator PGC-1

Muscle tissue is the major site for insulin-stimulated glucose uptake in vivo, due primarily to the recruitment of the insulin-sensitive glucose transporter (GLUT4) to the plasma membrane. Surprisingly, virtually all cultured muscle cells express little or no GLUT4. We show here that adenovirus-mediated expression of the transcriptional coactivator PGC-1, which is expressed in muscle in vivo but is also deficient in cultured muscle cells, causes the total restoration of GLUT4 mRNA levels to those observed in vivo. This increased GLUT4 expression correlates with a 3-fold increase in glucose transport, although much of this protein is transported to the plasma membrane even in the absence of insulin. PGC-1 mediates this increased GLUT4 expression, in large part, by binding to and coactivating the muscle-selective transcription factor MEF2C. These data indicate that PGC-1 is a coactivator of MEF2C and can control the level of endogenous GLUT4 gene expression in muscle.

Crc is involved in catabolite repression control of the bkd operons of Pseudomonas putida and Pseudomonas aeruginosa

Crc (catabolite repression control) protein of Pseudomonas aeruginosa has shown to be involved in carbon regulation of several pathways. In this study, the role of Crc in catabolite repression control has been studied in Pseudomonas putida. The bkd operons of P. putida and P. aeruginosa encode the inducible multienzyme complex branched-chain keto acid dehydrogenase, which is regulated in both species by catabolite repression. We report here that this effect is mediated in both species by Crc. A 13-kb cloned DNA fragment containing the P. putida crc gene region was sequenced. Crc regulates the expression of branched-chain keto acid dehydrogenase, glucose-6-phosphate dehydrogenase, and amidase in both species but not urocanase, although the carbon sources responsible for catabolite repression in the two species differ. Transposon mutants affected in their expression of BkdR, the transcriptional activator of the bkd operon, were isolated and identified as crc and vacB (rnr) mutants. These mutants suggested that catabolite repression in pseudomonads might, in part, involve control of BkdR levels.

An objective assessment of voice production after radiation therapy for stage I squamous cell carcinoma of the glottis

Radiation therapy has been the primary treatment for early glottic carcinoma, especially when restoration of normal voice is essential; yet objective evidence of the status of vocal function after treatment is lacking. The purpose of this study was to assess vocal characteristics of patients with glottic carcinoma after they had undergone radiation therapy. Twenty males, who had previously been treated with external beam irradiation for T1N0M0 squamous cell carcinoma with no subsequent evidence of recurrence, volunteered for this study. Laryngovideostroboscopic, acoustic, aerodynamic, and perceptual measures of vocal function were used to determine the characteristics of voice production. Acoustic indices were compared to those of a normal group of 30 age-matched volunteers, and the other measures were compared to established values reported in the literature. On acoustic analysis, the study group was characterized by significantly worse voice production than their counterparts. A high degree of intersubject variability was noted that could not be accounted for in terms of variables in treatment and medical history. The aerodynamic, spectral, and video-stroboscopic findings correlated well; this indicated a poor vibratory source, characterized by diffuse stiffness. Further work is necessary in order to compare vocal function after endoscopic laser and conventional conservative excision.

Cell wall lysin as a component of the bacteriophage phi 6 virion

Cell wall lytic activity was found in particles of the lipid-containing bacteriophage ø6. The activity can be extracted from the virion with Triton X-100 in the presence of salt. This treatment removes the membrane-like envelope of the virion which includes five proteins. The lysin requires detergent for in vitro activity. Virus particles formed in nonsuppressor cells by several classes of ø6 nonsense mutants contained the lysin activity; however, particles formed by a mutant (unable to make proteins P5 and P11) had very low activity; high activity was produced when particles were formed in a suppressor host. A study of the time course of the appearance of the lysin during infection showed that it appeared and increased in cells infected with wild-type virus and in suppressor cells infected with a mutant of class 511, but it did not increase in nonsuppressor cells infected with the class 511 mutant. It is concluded that protein P5 is a component of the lysin and that the role of its activity is in both early and late stages of infection. In particular, the lysin may be necessary for the passage of the infecting core of the virion through the cell wall of the bacterium, as well as in the final lysis necessary for the liberation of progeny phage. A mutant of the virus that produces a larger-than-normal protein P10 does not induce normal lysin activity in host Pseudomonas phaseolicola HB10Y, although it does in strain ERA Pseudomonas pseudoalcaligenes. This indicates that protein P5 is probably not sufficient for lysin activity, but the nature of the interaction between P5 and P10 is unknown.

Integration of simian virus 40 deoxyribonucleic acid into the deoxyribonucleic acid of primary infected Chinese hamster cells

Simian virus 40 deoxyribonucleic acid (DNA) became associated in an alkaline-stable form with the DNA of Chinese hamster embryo cells at 15 to 20 hr post-infection, at the time when cell DNA synthesis and T antigen were induced. The integration process was not inhibited by d-arabinosyl cytosine and was only partially inhibited by cycloheximide.

Electrical stimulation in exercise of the quadriceps femoris muscle

Thirty-seven healthy subjects took part in an investigation to determine if the application of electrical stimulation to normal muscle, in combination with exercise, augments strength. Subjects were divided into three groups. Grwoup A (n = 14) was a control group (no exercise, no electrical stimulation). Group B members (n = 11) engaged in 10 sessions of maximum isometric exercise, and Group C subjects (n = 12) performed 10 sessions of maximum isometric exercise while simultaneously receiving electrical stimulation. The knee extensor muscles of subjects in Groups B and C increased in strength. However, the strength gains for Groups B and C were equivalent, suggesting that electrical stimulation combined with maximum isometric contractions has no greater effect on enhancing strength than does conventional static exercise.

The increased need for a permanent pacemaker after reoperative cardiac surgery

OBJECTIVE

The requirement for permanent pacemaker implantation after most initial cardiac surgical procedures generally is less than 3%. To identify the incidence and factors related to permanent pacemaker need after repeat cardiac surgery, we retrospectively studied 558 consecutive patients undergoing at least one repeat cardiac operation.

METHOD

Univariable and multivariable analyses of comorbidity, preoperative catheterization values, and operative data were performed to identify factors related to pacemaker implantation.

RESULTS

In this group, 54 patients (9.7%) required a permanent pacemaker. A multivariable model showed a relationship between a permanent pacemaker and tricuspid valve replacement/annuloplasty associated with aortic/mitral valve replacement, preoperative endocarditis, increasing number of reoperations, the degree of hypothermia during cardiopulmonary bypass, and advanced age. Additional univariable predictors of pacemaker need included multiple valve replacement, increased cardiopulmonary bypass and aortic crossclamp times, and aortic valve replacement. Over 90% of patients who have or have not received permanent pacemaker implantation were in New York Heart Association class I to II, with a mean follow-up time of 6 years. Kaplan-Meier survival curves were statistically similar for both groups at 5 and 10 years after the operation.

CONCLUSION

Permanent pacemaker implantation was required in 9.7% of patients undergoing repeat cardiac surgery. This represented approximately a fourfold increase compared with similar primary operations reported in other series. Factors strongly related to this need included valve replacement, preoperative endocarditis, number of reoperations, advanced age, and degree of hypothermia during cardiopulmonary bypass. The need for a permanent pacemaker after reoperations did not result in significant long-term impairment of functional status or longevity compared with those who did not require a permanent pacemaker.

Laryngostroboscopic, acoustic, and environmental characteristics of high-risk vocal performers

Vocal performance often requires excessively high vocal demand. In particular "high-risk" performers, a group of individuals who use their voices at their maximum effort level, are often exposed to unique vocal abuse characteristics which include high environmental and performance demands and inconsistencies of cast performance. Three categories of high-risk performers were studied: musical theater, choral ensemble, and street theater. Musical theater performers produce a Broadway, West End "belting" style voice. Street theater performers use a high-energy pitch varying dialogue in order to imitate a desired character voice. Choral ensemble performance requires group cohesion and blending of four-part harmony. The melodies require sustained vocal durations within each of the respective registers. For each of these studied groups vocal tasks of sustained production of /i/ and /a/ were subjected to analysis. Acoustic measures included fundamental frequency, standard deviation of fundamental frequency, jitter percent, shimmer percent, and noise-to-harmonic ratio. Laryngostroboscopic parameters were assessed during sustained /i/. Environmental acoustic sound field measurements were made using an A weighting and linear weighting sound pressure level. These weightings were used to describe noise levels and vocal output, respectively, within the performance environments. Results of the analysis suggest that high-risk performers are a unique performance type defined by distinctive, acoustic, laryngostroboscopic, and environmental characteristics.

Characterisation of atovaquone resistance in Leishmania infantum promastigotes

Atovaquone, an antiparasitic agent, could possibly represent an alternative therapy after relapse following classical treatment for visceral leishmaniasis. Atovaquone-resistant strains were selected in vitro by stepwise drug pressure to study the mechanism of resistance in Leishmania. Characteristics of a promastigote strain resistant to 250 microg/ml of atovaquone were compared with those of the wild type (WT) strain. Resistant strains were shown to have a high level of resistance (45 times). They were stable in drug-free medium for 6 months, and showed no cross-resistance with other antileishmanial drugs. Rhodamine uptake and efflux were studied. They were not modified in the resistant strain, indicating the absence of P-glycoprotein overexpession. The effect of atovaquone on membrane lipidic composition was determined in both WT and atovaquone-resistant promastigotes. Analysis of lipid composition of the atovaquone-resistant strain showed that sterol biosynthesis was decreased in atovaquone-resistant parasites. Cholesterol was found to be the major membrane sterol as opposed to the WT strain. Cholesterol, due to its ordering effect, could decrease membrane fluidity and subsequently block the passage of atovaquone through the membrane. Increased membrane cholesterol content and altered drug membrane fluidity resulted from possible decrease of ergosterol biosynthesis by atovaquone, incorporation of cholesterol by promastigotes in the culture medium, solubilisation of atovaquone by cholesterol and co-passage of the two compounds or influence of dimethylsulfoxide. These results indicate that different cellular alterations may participate in the resistant phenotype, by altering drug membrane permeability.

Penetrance and expressivity of genes involved in the development of epilepsy in the genetically epilepsy-prone rat (GEPR)

In order to understand the level of complexity of the epileptic phenotype in the two strains of Genetically Epilepsy-Prone Rats (GEPRs), we determined two important measures of genetic complexity, penetrance and expressivity. Penetrance is the percentage of animals of a specific genotype who express the phenotype associated with that underlying genotype. Expressivity refers to the degree that a particular genotype is expressed as a phenotype within an individual. Incomplete penetrance and variable expressivity are caused by genetic and environmental variation. In this paper we have studied the epileptic phenotype for 20,373 rats. Animals were tested on three occasions for audiogenic seizure and given an audiogenic response score (on a scale of 0-9, 0 being no seizure and 9 being the most severe). The GEPR-3 and GEPR-9 animals both show incomplete penetrance and variable expressivity of the underlying genetic predisposition. The GEPR-9 strain has more animals that have variable levels of seizure predisposition (as measured by a scoring system that denotes the severity of generalized tonic/clonic seizures) and a greater percentage of animals that exhibit no susceptibility to such seizures induced by sound. Both strains have a number of animals that are not susceptible to sound-induced GTCSs and that exhibit some variability in seizure severity. The GEPR-9 males show greater differences in expressivity and penetrance compared to GEPR-9 females. The GEPR-3 animals also show sex-associated variable penetrance and expressivity of the epileptic phenotype, although the differences are much smaller. These findings are the first step toward the mapping of the underlying quantitative trait loci (QTL) for seizure in these animals.

Atomic clock with 1×10(-18) room-temperature blackbody Stark uncertainty

The Stark shift due to blackbody radiation (BBR) is the key factor limiting the performance of many atomic frequency standards, with the BBR environment inside the clock apparatus being difficult to characterize at a high level of precision. Here we demonstrate an in-vacuum radiation shield that furnishes a uniform, well-characterized BBR environment for the atoms in an ytterbium optical lattice clock. Operated at room temperature, this shield enables specification of the BBR environment to a corresponding fractional clock uncertainty contribution of 5.5×10(-19). Combined with uncertainty in the atomic response, the total uncertainty of the BBR Stark shift is now 1×10(-18). Further operation of the shield at elevated temperatures enables a direct measure of the BBR shift temperature dependence and demonstrates consistency between our evaluated BBR environment and the expected atomic response.

Characterization of phi 6 mutants that are temperature sensitive in the morphogenetic protein P12

P12 is a morphogenetic protein necessary for the envelopment of the bacteriophage phi 6 nucleocapsid with the viral membrane. Gene 12 is located along with three other genes on the smallest chromosome of the virion. ts mutants in P12 were obtained by first characterizing the isoelectric focusing behavior of phi 6 proteins and then screening ts mutants of phi 6 that had previously been assigned to chromosome C for changes in the behavior of P12. In this manner, three independently isolated mutants were identified and were found to have morphogenetic consequences at restrictive temperatures similar to gene 12 nonsense mutants in nonsuppressor cells in that only unenveloped nucleocapsids were formed. When infected cells were labeled at restrictive temperature, 27 degrees, and then shifted to 21 degrees, normal phage particles were formed; however, the hydrophobic membrane proteins in the particles were not labeled, indicating that functional P12 must be present at the time of synthesis of the membrane proteins for them to assemble into virions or that the defective P12 leads the membrane proteins into a nonfunctional pathway.

Imaging evaluation of suspected pulmonary embolism

Venous thromboembolism (VTE) is a common disorder that is difficult to diagnose clinically but carries significant morbidity and mortality if untreated. Additionally, although demonstrated to be of benefit in cases of proven deep vein thrombosis (DVT) and pulmonary embolism (PE), anticoagulation therapy is not without risk. Because the clinical exam is known to be unreliable for the detection of both DVT and PE, many imaging modalities have been used in the diagnostic imaging algorithm for the detection of VTE, including chest radiography, ventilation/perfusion (V/Q) scintigraphy, pulmonary angiography, and recently, spiral computed tomography (CT) and magnetic resonance imaging (MRI). Chest radiographic findings in acute PE include focal oligemia, vascular enlargement, atelectasis, pleural effusions, and air space opacities representing pulmonary hemorrhage or infarction. The chest radiograph can occasionally be suggestive of PE but is more often nonspecifically abnormal. The main use of the chest radiograph in the evaluation of suspected PE is to exclude entities that may simulate PE and to assist in the interpretation of V/Q scintigraphy. Lower extremity venous compression ultrasonography (CU) is both sensitive and specific for the diagnosis of femoropopliteal DVT, and the value of negative CU results has been established in outcomes studies. However, the reliability of CU for the detection of isolated calf vein thrombosis is not well established, and the clinical significance of such thrombi is debatable. Additional methods such as color and spectral Doppler analysis are also useful in the diagnostic evaluation of DVT but are best considered as adjuncts to the conventional CU examination rather than as primary diagnostic modalities themselves. Compression ultrasonography and Doppler techniques are useful in the evaluation of suspected upper extremity DVT; spectral Doppler waveform analysis is particularly useful to assess for the patency of veins that cannot be directly visualized and compressed with conventional gray-scale sonography. V/Q scintigraphy has been the initial modality obtained in patients suspected of PE for a number of years. Although many studies have investigated the role of V/Q scintigraphy in the evaluation of VTE, the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) study has provided the most useful information regarding the utility of V/Q scintigraphy in this setting. A high probability scan interpretation is sufficient justification to institute anticoagulation, and a normal perfusion scan effectively excludes the diagnosis of PE. A normal/near normal scan interpretation also carries a sufficiently low prevalence of angiographically proven PE to withhold anticoagulation. Although the prevalence of PE in the setting of low probability scan interpretations is low and several outcomes studies have demonstrated a benign course in untreated patients with low probability scan results, patients with inadequate cardiopulmonary reserve do not necessarily have good outcomes. Such patients deserve more aggressive evaluation. Patients with intermediate probability scan results have a 20% to 40% prevalence of angiographically proven PE and thus require further investigation. The radionuclide investigation of DVT includes such techniques as radionuclide venography and thrombus-avid scintigraphy. Although these methods have not been as thoroughly evaluated as CU, studies thus far have indicated encouraging results, and further investigations are warranted. Pulmonary angiography has been the gold standard for the diagnosis of PE for decades. Studies have indicated that angiography has probably been underutilized by referring physicians for the evaluation of suspected PE, likely because of the perception of significant morbidity and mortality associated with the procedure. (ABSTRACT TRUNCATED)

Internal jugular vein patency after functional neck dissection: venous duplex imaging

We present a retrospective study performed to determine jugular patency after functional neck dissection (FND). Twenty-six patients, 16 females and 10 males, ranging in age from 16 to 78 were examined. These patients underwent either unilateral FND or bilateral FND for cervical lymph node metastases. Cervical duplex and pulsed Doppler imaging were chosen to determine internal jugular vein (IJV) patency. The examination was performed after a minimum postoperative period of 2 months and a maximum one of 22 years. Thirty-one IJVs were examined. All but 4 IJVs examined were found patent postoperatively. The preservation rate of patency of the IJV in FND was found to be high (27 of 31 or 87%). These results favor the use of FND for IJV preservation, particularly in bilateral neck dissection.

Synthesis of polymer-derived ceramic Si(B)CN-carbon nanotube composite by microwave-induced interfacial polarization

We demonstrate synthesis of a polymer-derived ceramic (PDC)-multiwall carbon nanotube (MWCNT) composite using microwave irradiation at 2.45 GHz. The process takes about 10 min of microwave irradiation for the polymer-to-ceramic conversion. The successful conversion of polymer coated carbon nanotubes to ceramic composite is chemically ascertained by Fourier transform-infrared and X-ray photoelectron spectroscopy and physically by thermogravimetric analysis and transmission electron microscopy characterization. Frequency dependent dielectric measurements in the S-Band (300 MHz to 3 GHz) were studied to quantify the extent of microwave-CNT interaction and the degree of selective heating available at the MWCNT-polymer interface. Experimentally obtained return loss of the incident microwaves in the specimen explains the reason for heat generation. The temperature-dependent permittivity of polar molecules further strengthens the argument of internal heat generation.

Ex vivo purging by adenoviral p53 gene therapy does not affect NOD-SCID repopulating activity of human CD34+ cells

Co-incubation of a replication-deficient, recombinant adenovirus carrying the wild-type p53 gene (rAd-p53) and hematopoietic stem cell (HSC) products from patients with breast cancer can significantly reduce tumor cell contamination. Whereas this approach provides a powerful tumor cell purging strategy, potential detrimental effects on the HSC population have not been investigated. The ability of human HSC to reconstitute hematopoiesis in severe combined immunodeficient (SCID) mice and to undergo secondary transplantation provides the only nonclinical measure of self-renewing, stem cell function. The objective of this study was to investigate whether co-incubation with rAd-p53 compromised the SCID repopulating activity (SRA) of HSC. Granulocyte colony-stimulating factor-mobilized human CD34+ cells were co-cultured with rAd-p53 at our targeted clinical dose, and the ability of these cells to establish multilineage hematopoiesis in sublethally irradiated, nonobese diabetic (NOD)-SCID mice was investigated. The persistence of human cells in the mice was investigated by flow cytometry, granulocyte-macrophage colony-forming unit assay, and polymerase chain reaction of human Alu sequences. Further, limiting dilution analysis provided a quantitative comparison between the SRA of CD34+ cells co-incubated with rAd-p53 and control CD34+ cells (no rAd-p53 co-incubation). We conclude that co-incubation with rAd-p53 has little effect on the SRA of HSC.

Achievement correlates of the Woodcock-Johnson Reading and Mathematics Subtests, KeyMath, and Woodcock Reading in an elementary aged learning disabled population

Thirty-two elementary aged learning-disabled students were administered the math and reading subtests from the Woodcock-Johnson Psycho-Educational Battery, KeyMath, and Woodcock Reading Mastery Tests. Grade equivalent scores and standard scores were compared and yielded significant correlations that range from .79 to .93. Mean grade equivalent scores did however significantly differ for the two reading measures but not when standard scores were used. The two math indices yielded nonsignificant grade equivalent scores. Similarities and differences between the instruments are discussed in relation to enhancing the identification of learning disabilities.

The effects of an in-service program upon the attitudes of nursing aides

Twenty-six female nursing aides were divided into two groups to determine whether an in-service training program would enhance their attitudes toward physically disabled geriatric patients requiring custodial care. The Attitude Toward Disabled Persons Questionnaire (ATDP) was administered to the experimental and control groups before and after the in-service training program. Each in-service program consisted of a lecture on a specific topic followed by informal discussion of patient care. Three research hypotheses were tested to evaluate the effectiveness of the in-service program in altering attitudes toward the physically disabled: (1) The experimental group would score higher on post-test than on pre-test; (2) The control group would not score higher on post-test than on pre-test; and (3) The experimental group would change more from pre-test to post-test than would the control group. All three research hypotheses were supported (the first at p less than .005 and the third at p less than .01). Limitation of the study and suggestions for further research were discussed.