An unusual lightning flash at kennedy space center.

A lightning flash that struck the 150-meter weather tower at Kennedy Space Center was studied by several research groups using varioul techniques. The flash had unusually large peak currents and a stepped leader of relatively short duration. The charged regions neutralized by the three return strokes were located within a horizontal layer between heights of about 6 and 8 kilometers, where environmental temperatures were about -10 degrees to -20 degrees C. The charge source for the first return stroke coincided with a vertical shaft of precipitation inferred to have been graupel or hail. Charge sources for subsequent strokes were near the edge of the detectable precipitation echo. The overall channel length was about 10 kilometers. A Vertically oriented intracloud discharge occurred after the three return strokes.

Ablation of the murine alpha myosin heavy chain gene leads to dosage effects and functional deficits in the heart.

The alpha-myosin heavy chain (alpha-MyHC) is the major contractile protein expressed in the myocardium of adult mice. We have produced mice carrying a null mutation of alpha-MyHC by homologous recombination in murine ES cells. Homozygous null animals die between 11 and 12 d in utero of gross heart defects, while alpha-MyHC+/- heterozygotes survive and appear externally normal. The presence of a single functional alpha-MyHC+ allele in heterozygous animals results in reduced levels of the transcript and protein as well as fibrosis and alterations in sarcomeric structure. Examination of heart function using a working heart preparation revealed severe impairment of both contractility and relaxation in a subset of the alpha-MyHC+/- animals. Thus, two alpha-MyHC+ alleles are necessary for normal cardiac development, and hemizygosity for the normal allele can result in altered cardiac function.

Mouse model of desmin-related cardiomyopathy.

BACKGROUND: The consequence of upregulation of desmin in the heart is unknown. Mutations in desmin have been linked to desmin-related myopathy (DRM), which is characterized by abnormal intrasarcoplasmic accumulation of desmin, but direct causative evidence that a desmin mutation leads to aberrant intrasarcoplasmic desmin accumulation, aggregation, and cardiomyopathy is lacking. METHODS AND RESULTS: Multiple transgenic mouse lines that expressed either murine wild-type desmin or a 7-amino acid deletion (R173 through E179) desmin (D7-des) mutation linked to DRM were made. The distribution of desmin protein was unchanged, and no overt phenotype was detected in the wild-type desmin transgenic mice. In contrast, the D7-des mouse heart showed aberrant intrasarcoplasmic and electron-dense granular filamentous aggregates that were desmin-positive and characteristic of human DRM. The desmin filament network was significantly disrupted, and myofibril alignment was visibly compromised. Although systolic function at the whole-organ level was substantially conserved in the young adult animals, the ability of the heart to respond to beta-agonist stimulation, as measured in the intact animal, was significantly blunted. CONCLUSIONS: Upregulation of desmin protein at moderate levels is not detrimental. However, the D7-des mutation is dominant negative, and expression of the mutant protein leads to the appearance of aggregates that are characteristic of and diagnostic for human desmin-related cardiomyopathy.

A multipurpose vector for the study of transcriptional control.

To facilitate the insertion of transcriptional control regions next to a reporter gene, plasmid vectors containing multiple cloning sites next to the cat have been constructed. These vectors also contain features which make their use convenient for the construction of deletions in the inserted transcriptional control regions, as well as for the direct sequencing of the deletion series produced. The vectors have been constructed such that the control region cassette (and the deletions produced) may be easily removed with or without the reporter gene for placement into transgenic mice. The system's utility has been demonstrated by deletion analysis of a chicken myosin heavy chain-encoding gene promoter.

Benign myoepithelioma of the lung: a case report and review of the literature.

This report describes a benign myoepithelioma of the lung that occurred in a 60-year-old woman. The patient had experienced hoarseness for 6 weeks, and a computed tomographic scan showed a nodule of approximately 2 cm in diameter at the peripheral portion of her right upper lung. Positron emission tomography showed no uptake of F-18 fluorodeoxyglucose in the nodule. Wedge biopsy of the lesion showed benign spindle cells arranged in a whorled pattern. The cells were positive for both cytokeratin and smooth muscle actin, which corresponded to the presence of tonofilaments and myofilaments that were identified ultrastructurally. The features of the present case of benign myoepithelioma that differ from features of previously reported benign and malignant cases of myoepithelioma in the lung are discussed in the report.

Exercise treatment for sacroiliac pain.

The reciprocal relationship of the latissimus dorsi on one side and the gluteus maximus on the other side has been demonstrated anatomically. To demonstrate this relationship by muscle action, electromyographic studies were performed in 15 healthy individuals. This formed the baseline for evaluation of 5 symptomatic patients with sacroiliac dysfunction. Abnormal hyperactivity of the gluteus muscle on the involved side and increased activity of the latissimus on the contralateral side was contrasted with the normal function of the healthy individuals. All patients in the rotary strengthening exercise program improved in strength and return of myoelectric activity to more normal patterns.

Hepatitis C virus infection management in 2012.

Hepatitis C virus (HCV) is the most common infectious cause of chronic liver disease in Europe. With the introduction of interferon based therapy in combination with ribavirin treatment of chronic HCV has become feasible. This therapy has become the standard of care for patients with HCV and depending on the HCV genotype treatment is successful in 40-70% of patients. In the recent years a new class of drugs have emerged that changed the landscape of HCV treatment. These direct antiviral agents inhibit the NS3/N4A serine protease of HCV. Prototypes are telaprevir and boceprevir and they specifically exert antiviral activity against genotype 1 HCV. A series of landmark trials has paved the way for introduction of these agents, and they have documented a great improvement in the care of genotype 1 HCV patients. Telaprevir and boceprevir are given in combination with pegylated interferon and ribavirin and are useful for treatment naive as well as treatment experienced patients. The clinician should be aware of these developments as they have implications for side effect management, and drug-drug interactions. Finally, strategic use of these agents comes with stopping rules and require close monitoring of the HCV viral load.

Molecular mechanics of cardiac myosin-binding protein C in native thick filaments.

The heart's pumping capacity results from highly regulated interactions of actomyosin molecular motors. Mutations in the gene for a potential regulator of these motors, cardiac myosin-binding protein C (cMyBP-C), cause hypertrophic cardiomyopathy. However, cMyBP-C's ability to modulate cardiac contractility is not well understood. Using single-particle fluorescence imaging techniques, transgenic protein expression, proteomics, and modeling, we found that cMyBP-C slowed actomyosin motion generation in native cardiac thick filaments. This mechanical effect was localized to where cMyBP-C resides within the thick filament (i.e., the C-zones) and was modulated by phosphorylation and site-specific proteolytic degradation. These results provide molecular insight into why cMyBP-C should be considered a member of a tripartite complex with actin and myosin that allows fine tuning of cardiac muscle contraction.

Hepatic and renal manifestations in autosomal dominant polycystic kidney disease: a dichotomy of two ends of a spectrum.

Autosomal dominant polycystic kidney disease (ADPKD) is a multisystem disorder. It is the most common genetic cause of end-stage renal disease. One frequent extra-renal manifestation is hepatic cyst formation. The majority of ADPKD patients develop complications as a result of renal cyst formation; however, a small proportion develop extensive hepatic disease with minor renal features. Both phenotypes seem to represent the spectrum of ADPKD. This review discusses the current understanding of the pathogenesis of the disease, its manifestations and the mechanisms of cyst formation. Furthermore, it focuses on monitoring the disease and the treatment options currently available.

Changing gender roles of Egyptian females.

A high population growth rate in the Middle East is prompting investigators to look for cultural conditions and attitudes that can be encouraged to facilitate lower fertility rates. Population researchers find an inverse relationship between the educational level of females and their fertility, especially in Third World countries. This suggests that education can become an internal cultural mechanism for population control. The author explores this notion using data collected from interviews with 750 teenage girls and their mothers in Cairo, Egypt.

A canonical sequence organization at the 5'-end of the myosin heavy chain genes.

The sequences encoding the 5'-ends of three chicken fast-white myosin heavy chain (MHC) genes have been determined. When compared with the sequences of two other MHC genes it is apparent that both the exon and intron positions are conserved. All exon sequences are highly conserved; there is absolute amino acid conservation in the second and third exons. In addition, while the first and third introns diverge among the genes, the second intron is highly conserved between the five. This intron contains a 24-bp sequence that is repeated twice in one of the introns and once in the other four. Analyses indicate that this sequence, which is partially homologous to 7SL RNA, appears to be largely restricted to the MHC gene family. Analysis of the 5'-flanking sequences show that while small homologies are present between some of the genes, they have extensively diverged in this region.

The developmentally regulated expression of two linked myosin heavy-chain genes.

The organization of two linked chicken myosin heavy-chain (MHC) genes is described. Using probes derived from the 3' and 5' ends of the genes, chromosome walks were carried out, resulting in the isolation of a clone which encompassed the 5' end of one MHC gene and the 3' end of a different MHC gene. Further analysis showed that both genes (each approximately 25 kbp in length) are oriented head to tail and are separated by an intergenic region of 7.5 kbp. Despite extensive homologies, a transcript-specific probe for each of the genes could be prepared from the 5' untranslated regions. These probes were used to determine the transcriptional pattern for each of the genes. The data show that the gene located at the 5' end of the linkage pair is expressed during the neonatal stages of development, while the gene located at the 3' end of the pair is expressed predominantly during the embryonic stages of development.

A preliminary report on the effect of measured strength training in adolescent idiopathic scoliosis.

The authors studied 12 adolescent patients with scoliosis (10 girls and 2 boys) who were 11 to 16 years old and had curvatures ranging from 20 degrees to 60 degrees. Seven were right thoracic curves and five were thoracolumbar with double curves. When tested on the MedX Torso Rotation Machine, both sides were unequal in their torso rotation strength all patients. Myoelectric activity was asymmetric in both sides and in abdominal and paraspinal muscles of all patients. These asymmetries were corrected completely with torso rotation, which was associated with significant strength gains. Strength gains ranged from 12% to 40%. A 16-year-old girl with a 60 degree lumbar curve progressed and had surgery. None of the remaining patients progressed, and 4 of the 12 had decreases in their curvatures from 20 degrees to 28 degrees. None of the patients used braces during this study.

Analysis of the upstream regulatory region of a chicken skeletal myosin heavy chain gene.

The organization of the cis-acting regulatory elements of a chick myosin heavy chain gene has been investigated. The data show that a gene which is transcribed in vivo in the fast white embryonic musculature is also the major transcript expressed during myotube differentiation of primary myoblasts derived from 12-day embryonic chick leg muscles. The upstream region of this gene consists of 7500 base pairs, and we have tested the ability of these sequences to drive expression of the chloramphenicol acetyltransferase gene in developing primary muscle cultures. Deletion analyses of the upstream region show that negative regulatory elements are present within 2000 base pairs of the basal promoter elements, the CCAAT and TAATA boxes. Removal of these elements reveals the presence of a strong positive element located near the start site of transcription. Sequence analysis showed that the region also contains a sequence characteristic of an enhancer found in the immunoglobulin heavy chain gene, ATGCAAAT, the "octa" element. Gel band-shift assays show that this octa sequence binds a transacting factor present in muscle nuclear extracts, although footprint analysis indicates a limited interaction. Transient assays carried out with a fragment in which the octa sequence has been mutated, with the subsequent abolition of protein binding, shows that the particular interaction probably plays a role in negatively modulating the action of the strong positive promoter element.

The structure of two fast-white myosin heavy chain promoters. A comparative study.

Two complete myosin heavy chain genes were isolated from chicken genomic libraries, and shown to code for fast-white isoforms. Isoform specific probes were developed from the 5' nontranslated regions of the two genes and used to identify the developmental stages at which each of the genes are expressed. One of the genes is transcribed in the embryo and the other only in the adult. The 5' flanking regions of the two genes were sequenced along with the first three exons. The 5' untranslated sequences in both genes are not contiguous, one intron is present in the adult gene while the embryonic gene contains two. The promoters of both genes contain the conserved CAAT and TATA box elements observed in other eucaryotic genes. A computer assisted comparison was performed on the two genes at the nucleotide and amino acid levels. No homology could be detected in the 5' flanking regions of the genes except in and around the CAAT and TATA elements, however, structural sequences at the 5' ends were highly conserved as well as the position of the first three introns. The amino acids in and around the ATP binding site are completely conserved between the two isoforms.

Isolation and characterization of the mouse cardiac myosin heavy chain genes.

Two mouse genomic libraries were probed in order to isolate the murine cardiac myosin heavy chain (MHC) genes. Two overlapping cosmid clones that encode the cardiac genes were isolated. One of them encompasses the entire alpha-cardiac MHC gene, its 5'-flanking region and approximately 10 kilobase pairs (kb) of the 3'-end of the beta-cardiac MHC gene which we determined is located approximately 4 kb upstream of the alpha-cardiac MHC gene. Four clones isolated from a bacteriophage library were found to overlap with the 5'-region of the cosmid clones, and sequence analysis confirmed that the 5'-end of the beta-cardiac MHC gene was contained within one of the clones. Primer extension and polymerase chain reaction (PCR) analyses were used to define the transcriptional start site and the 5'-organization of the alpha-cardiac MHC gene. This region exhibits greater than 90% homology to the corresponding nucleotides of the rat alpha-cardiac MHC gene. To assess the importance of the intergenic region in directing expression of the alpha-cardiac MHC gene, a fragment containing the 3'-end of the beta-cardiac gene and the 5'-end of the alpha-cardiac gene was linked to a chloramphenicol acetyltransferase gene and used to generate transgenic mice. Analyses of the chloramphenicol acetyltransferase (CAT) activity in two lines indicate that the intergenic region is sufficient to properly direct expression in a tissue-specific manner.

The chicken myosin heavy chain family.

We have used a myosin heavy chain gene fragment to probe two chicken genomic libraries. The fragment, derived from a gene expressed in the fast-white fibers of adult chickens, contains 1400 bases upstream from the translational start site and 1600 bases downstream from the initiation codon. Thirty-one unique nonoverlapping clones were isolated. All of the genes showed homologies in the nucleotide sequences which code for the globular head portion of the myosin protein while no extensive homologies were detected in the 5'-flanking sequences. The relationships between the genes were studied using oligomeric sequences as probes. The hybridization patterns showed that seven of the genes fall within a well defined subgroup. The exon containing a domain of the nucleotide (ATP) binding site was sequenced for all seven of these genes and shown to be, except for 2 nucleotides in one of the genes, completely conserved. The lack of sequence conservation in the 5'-nontranslated portions of the genes was exploited in the preparation of transcript-specific probes. We have used these probes to show that two of the isoforms are expressed in a tissue-specific and developmental stage-specific manner in the chicken.

Structural and transcriptional analysis of a chicken myosin heavy chain gene subset.

Recently we have isolated a large number of chicken myosin or myosin-like heavy chain genes. Seven of these genes were placed into a subset based upon their hybridization patterns. In the present study, the sequence of the 5' end of one of the myosin heavy chain (MHC) genes, N127, was determined and compared with the 5' end sequences of the other six MHC genes in the subset. The comparison revealed that the three exons encoding the amino termini of the protein are highly conserved. The sequence analysis shows that a localized correction event occurred in and around a domain of the nucleotide-binding site, as the exon encoding this site and the preceding intron are very highly conserved among the seven genes. The sequence of the promoter and 5'-untranslated region of N127 is presented. The analogous regions for N124 and N125 have now been sequenced and are also presented. As is the case for all the other known MHC genes, the 5'-untranslated regions are split by large introns. The promoter and 5'-untranslated regions are compared with two previously characterized chicken MHC genes (N116 and N118) to determine the sequence similarities and differences that might underlie the differential expression of the family's members. To confirm and extend previously published results of the expression of these genes, transcript-specific probes generated from the 5' region of six of the seven genes were used to determine in which muscle(s) the corresponding mRNAs were present. The data show that despite the very close structural homologies, each of the genes for which a unique probe could be prepared exhibits a unique pattern of expression.

Examining the in vivo role of the amino terminus of the essential myosin light chain.

The functional significance of the actin binding region at the amino terminus of the cardiac essential myosin light chain (ELC) remains obscure. Previous experiments carried out in vitro indicated that modulation of residues 5-14 could induce an inotropic effect, increasing maximal ATPase activity at submaximal Ca(2+) concentrations (Rarick, H. M., Opgenorth, T. J., von Geldern, T. W., Wu-Wong, J. R., and Solaro, R. J. (1996) J. Biol. Chem. 271, 27039-27043). Using transgenesis, we effected a cardiac-specific replacement of ELC with a protein containing a 10-amino acid deletion at positions 5-14. Both the ventricular (ELC1vDelta5-14) and atrial (ELC1aDelta5-14) isoforms lacking this peptide were stably incorporated into the sarcomere at high efficiencies. Surprisingly when the kinetics of skinned fibers isolated from the ELC1vDelta5-14 or ELC1aDelta5-14 mice were examined, no alterations in either unloaded shortening or maximum shortening velocities were apparent. Myofibrillar Mg(2+)-ATPase activity was also unchanged in these preparations. No significant changes in the fiber kinetics in the cognate compartments were observed when either deletion-containing protein replaced endogenous ELC1v or ELC1a. The data indicate that the previously postulated importance of this region in mediating critical protein interactions between the cardiac ELCs and the carboxyl-terminal residues of actin in vivo should be reassessed.

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.