Myofiber-type-dependent 'boulder' or 'multitudinous pebble' formations across distinct amylopectinoses

At least five enzymes including three E3 ubiquitin ligases are dedicated to glycogen's spherical structure. Absence of any reverts glycogen to a structure resembling amylopectin of the plant kingdom. This amylopectinosis (polyglucosan body formation) causes fatal neurological diseases including adult polyglucosan body disease (APBD) due to glycogen branching enzyme deficiency, Lafora disease (LD) due to deficiencies of the laforin glycogen phosphatase or the malin E3 ubiquitin ligase and type 1 polyglucosan body myopathy (PGBM1) due to RBCK1 E3 ubiquitin ligase deficiency. Little is known about these enzymes' functions in glycogen structuring. Toward understanding these functions, we undertake a comparative murine study of the amylopectinoses of APBD, LD and PGBM1. We discover that in skeletal muscle, polyglucosan bodies form as two main types, small and multitudinous ('pebbles') or giant and single ('boulders'), and that this is primarily determined by the myofiber types in which they form, 'pebbles' in glycolytic and 'boulders' in oxidative fibers. This pattern recapitulates what is known in the brain in LD, innumerable dust-like in astrocytes and single giant sized in neurons. We also show that oxidative myofibers are relatively protected against amylopectinosis, in part through highly increased glycogen branching enzyme expression. We present evidence of polyglucosan body size-dependent cell necrosis. We show that sex influences amylopectinosis in genotype, brain region and myofiber-type-specific fashion. RBCK1 is a component of the linear ubiquitin chain assembly complex (LUBAC), the only known cellular machinery for head-to-tail linear ubiquitination critical to numerous cellular pathways. We show that the amylopectinosis of RBCK1 deficiency is not due to loss of linear ubiquitination, and that another function of RBCK1 or LUBAC must exist and operate in the shaping of glycogen. This work opens multiple new avenues toward understanding the structural determinants of the mammalian carbohydrate reservoir critical to neurologic and neuromuscular function and disease.

Laforin targets malin to glycogen in Lafora progressive myoclonus epilepsy

Glycogen is the largest cytosolic macromolecule and is kept in solution through a regular system of short branches allowing hydration. This structure was thought to solely require balanced glycogen synthase and branching enzyme activities. Deposition of overlong branched glycogen in the fatal epilepsy Lafora disease (LD) indicated involvement of the LD gene products laforin and the E3 ubiquitin ligase malin in regulating glycogen structure. Laforin binds glycogen, and LD-causing mutations disrupt this binding, laforin-malin interactions and malin's ligase activity, all indicating a critical role for malin. Neither malin's endogenous function nor location had previously been studied due to lack of suitable antibodies. Here, we generated a mouse in which the native malin gene is tagged with the FLAG sequence. We show that the tagged gene expresses physiologically, malin localizes to glycogen, laforin and malin indeed interact, at glycogen, and malin's presence at glycogen depends on laforin. These results, and mice, open the way to understanding unknown mechanisms of glycogen synthesis critical to LD and potentially other much more common diseases due to incompletely understood defects in glycogen metabolism.

Cumulative pregnancy and live birth rates after gamete intra-Fallopian transfer

To evaluate the efficacy of gamete intra-Fallopian transfer (GIFT) the Kaplan-Meier life table method was used to analyse a patient cohort treated with GIFT between 1991 and 1994. In a tertiary referral centre for reproductive medicine, 1628 women with a median age of 33 years and various causes of infertility were included to calculate cumulative pregnancy and live birth rates. Age and cause of infertility were main factor variables and the study was based on a total of 2941 consecutive GIFT cycles, leading to a first clinical pregnancy, and 3052 cycles, leading to a first live birth. The cumulative pregnancy and live birth rates were 49.6 and 38.8% respectively, after three initiated cycles and 64.1 and 52.0% respectively, after five initiated cycles. The multiple pregnancy rate was 22.6%. The implantation rate of 13.1% after GIFT demonstrates that the developing embryo benefits from a period of exposure within the environment of the Fallopian tube. The present results indicate that approximately 50% of couples will have at least one live baby after five initiated GIFT cycles. Advancing age was a major negative prognostic factor for the cumulative live birth rate because of higher cancellation rates, lower implantation rates and higher pregnancy failure rates.

Comparison of two schema for classifying nursing research

To examine trends in nursing research during the last five years of the 1980s and to test the reliability and validity of two taxonomic schemes to classify nursing research, 811 abstracts from three years of a national nursing research conference (Council of Nurse Researchers, 1983, 87, 89) were reviewed and classified independently by three investigators. Taxonomies were research topics as categorized in the Sigma Theta Tau International Directory of Nurse Researchers (STT) and the Classification of Nursing-Related Dissertations (DISSER). More than half of abstracts addressed clinical topics, and clinical research topics increased significantly over time (p less than .001). At least two of the three raters agreed on coding for 62.8 percent of abstracts with STT schemes, 70.9 percent with DISSER scheme (p less than .01). Additional testing and standardization of taxonomies for nursing research is needed to improve reliability and validity.

A model for predicting utilization of psychiatric facilities

This paper develops a parsimonious model for predicting utilization of a regional system of psychiatric facilities based on census data. The model combines conceptual simplicity with readily-available data sources. In practical terms, the model removes the need to undertake comprehensive and expensive utilization surveys. In theoretical terms, the model indicates that the fundamental relationship between utilization rates and key social indicators is stable through time. Although further testing is necessary, it would seem that these key indicators can provide reasonable estimates of psychiatric morbidity for up to ten years in the future.

Impact of mental health facilities on property values

Community opposition to the establishment of a small-scale mental health facility is often intense. One frequently voiced fear is that the estabishment of a facility will cause property values in its vicinity to decline. This paper examines empirical evidence of the impact on property values in the neighborhood of 12 mental health centers in Philadelphia. It is concluded that such facilities have an indeterminate effect on property values in their vicinity, contary to popular opinion.