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Biomedical subjects

C E Kasper

Publications and source records attributed to C E Kasper.

At least 19 recordsLinked to original sources
PubMed2000

Expression of titin in skeletal muscle varies with hind-limb unloading.

The effects of prolonged hind-limb unloading on titin antibody localization and expression of titin isozymes of single fibers from the synergistic slow-twitch soleus (SOL) and fast-twitch plantaris (PLN) of adult rats were studied after 14 and 28 days of hind-limb unloading (HU). Titin antibody localization and expression was not altered at 14 days of HU. However, there was a 4% loss in antibody to Z-band distance (Ab-Z) in the SOL and an increase of 8% in PLN Ab-Z after 28 days of HU. The titin and myosin heavy chain composition of single fibers and small bundles of fibers from control and unloaded muscles were examined using 2% to 12% sodium dodecyl sulfate-polyacrylamide gel electrophoresis. There was a marked loss of relative amounts of titin in both SOL and PLN following 28 days of HU. As the protein loads for these measures were identical, the authors conclude that these findings represent an actual loss of titin density rather than a decreased value due to a loss of total muscle mass. Laser scanning densitometry of the titin bands show a marked decrease in density and molecular weight in unloaded SOL. In the PLN, marked losses of titin density were accompanied by decreased electrophoretic motility. The results demonstrate that the titin isoform composition and titin antibody localization of skeletal muscle is altered during hind-limb unloading. Furthermore, as titin is responsible for positional stability of the sarcomere and the fiber during contraction, change in isoforms during HU may predispose atrophied muscle to injury during reuse and recovery.

Animals↗
PubMed2000

Influence of adjuvant chemotherapy on skeletal muscle and fatigue in women with breast cancer.

The purpose of this pilot study was to investigate the changes in skeletal muscle size and strength and perception of fatigue in women undergoing adjuvant chemotherapy for breast cancer. The findings of this pilot study suggest that changes in muscle size and strength can occur during chemotherapy. Quadricep muscle size increased for two subjects. These subjects also experienced an increase in muscle strength. This is the first known study to address change in muscle size and fatigue in women during adjuvant chemotherapy for breast cancer from an integrated biobehavioral perspective. Our findings may indicate that muscle size can increase during chemotherapy, but this may not diminish the subjective experiences of fatigue. As the potential for causing serious damage to striated muscle exists, further research into muscle changes and activity during chemotherapy and its role in fatigue is crucial.

Activities of Daily Living↗
PubMed1999

Recovery of plantaris muscle from impaired physical mobility.

The purpose of this investigation was to describe and compare various methods of recovering atrophied fast-twitch skeletal muscle following long-term impaired physical mobility. An animal model was used to study morphological adaptations of atrophied plantaris muscles to the effects of 28 days of hindlimb suspension (HS) followed by either sedentary recovery or run training during a 28-day recovery period. Significant atrophy, demonstrated by decreased mean fiber area (MFA, micron 2), occurred during the 28-day period of HS. However, run training following long-term atrophy induced by HS did not result in the high levels of frank muscle damage and type IIC fibers previously reported in slow-twitch soleus muscle following long-term (28 days) atrophy.

Animals↗
PubMed1999

Spatial patterns of atrophied muscle fibers during exercised recovery.

The effect of run training during the recovery period on the spatial distributions of fiber type was examined in atrophic soleus muscle of adult rats following 28 days of hindlimb suspension. During recovery, clusters of damaged and type IIC fibers were observed, which were more pronounced in the exercised animals than in both exercised and nonexercised control groups. The results indicate that exercise during recovery following suspension-induced hindlimb muscle atrophy produces changes in the soleus fiber-type cross-sectional area, both absolute and relative. These changes were not seen in the sedentary recovery group or in control rats exposed to the same exercise regimen. The author concludes that this treatment, unlike neurogenic pathologies, does not cause any remodeling during recovery, in the sense of changed adjacency relations among fiber types.

Animals↗
PubMed1997

Enhancing adenosine A1 receptor binding reduces hypoxic-ischemic brain injury in newborn rats.

Hypoxia increases brain adenosine concentrations, which provides neuroprotection through activation of central adenosine A1 receptors. This study was carried out to determine whether PD 81,273, which increases adenosine's binding to A1 receptors, would reduce hypoxia-induced brain injury. PD 81,273 (3 mg/kg, i.p.) decreased by about 50% the weight loss of the left cerebral hemisphere caused by hypoxia-ischemia in neonatal rats. Thus, enhancing adenosine's binding to the A1 receptor decreases hypoxic brain damage.

Animals↗
PubMed1996

Alterations in skeletal muscle related to short-term impaired physical mobility.

The purpose of this investigation was to describe and compare two methods of recovery of atrophied skeletal muscle following short-term impaired physical mobility. An animal model was used to study morphologic adaptations of atrophied soleus and plantaris muscles to the effects of 7 days of hind-limb suspension (HS) followed by either sedentary recovery or run training during a 28-day recovery period. Significant atrophy, demonstrated by decreased mean fiber area (MFA, in square micrometers), occurred during the 7-day period of HS. During recovery, MFA returned to control values 14 days earlier in the sedentary compared with the trained groups. Runs training following short-term atrophy induced by HS did not result in the high levels of frank muscle damage and type IIC fibers previously reported following long-term (28-day) atrophy.

Analysis of Variance↗
PubMed1996

Cytoplasm-to-myonucleus ratios following microgravity.

The cytoplasmic volume-to-myonucleus ratio in the tibialis anterior and gastrocnemius muscles of juvenile rats after 5.4 days of microgravity was studied. Three groups of rats (n = 8 each) were used. The experimental group (space rats) was flown aboard the space shuttle Discovery (NASA, STS-48), while two ground-based groups, one hindlimb suspended (suspended rats), one non-suspended (control), served as controls. Single fibre analysis revealed a significant decrease in cross-sectional area (microns2) in the gastrocnemius for both the space and the suspended rats; in the tibialis anterior only the suspended rats showed a significant decrease. Myonuclei counts (myonuclei per mm) in both the tibialis anterior and gastrocnemius were significantly increased in the space rats but not in the suspended rats. The mean myonuclear volume (individual nuclei: microns3) in tibialis anterior fibres from the space rats, and in gastrocnemius fibres from both the space and the suspended rats, was significantly lower than that in the respective control group. Estimation of the total myonuclear volume (microns3 per.mm), however, revealed no significant differences between the three groups in either the tibialis anterior or gastrocnemius. The described changes in the cross-sectional area and myonuclei numbers resulted in significant decreases in the cytoplasmic volume-to-myonucleus ratio (microns3 x 10(3)) in both muscles and for both space and suspended rats (tibialis anterior; 15.6 +/- 0.6 (space), 17.2 +/- 1.0 (suspended), 20.8 +/- 0.9 (control): gastrocnemius; 13.4 +/- 0.4 (space) and 14.9 +/- 1.1 (suspended) versus 18.1 +/- 1.1 (control)). These results indicate that even short periods of unweighting due to microgravity or limb suspension result in changes in skeletal muscle fibres which lead to significant decreases in the cytoplasmic volume-to-myonucleus ratio.

Animals↗
PubMed1996

Cytoplasm-to-myonucleus ratios in plantaris and soleus muscle fibres following hindlimb suspension.

In multinucleated skeletal muscle fibres the size of the cytoplasmic volume-to-myonucleus ratio is related to the myosin heavy chain phenotype, with the ratio being larger in those fibres expressing the fast myosin heavy chain phenotype. It is unknown, however, whether this ratio is modulated during muscle fibre adaptation, such as that which occurs following muscle unloading. In this study the relationship between cross sectional area, myonuclear number and myosin type, in single fibres from the plantaris and soleus muscles of adult rats following 28 days of hindlimb suspension was examined. Each fibre was cut transversely into two segments; one segment was used for immunohistochemical identification of myosin type, the other for determination of cross sectional area and myonuclei number. Single fibre analysis revealed significant atrophy of both plantaris fast and soleus slow fibres; the mean cross sectional area (microns2) of these fibres, 3104 +/- 183 and 2082 +/- 107 (mean +/- SE), being 70 and 45%, respectively, of control means. The decreases in cross sectional area were not accompanied by corresponding decreases in the number of myonuclei (myonuclei/mm); in plantaris fast fibres the mean myonuclei counts were within the control range (88 +/- 8 (hindlimb suspension), 76 +/- 7 (control), in soleus slow fibres the counts were significantly increased (185 +/- 12 (hindlimb suspension), 154 +/- 11 (control)). The changes resulted in a significant decrease in the cytoplasmic volume-to-myonucleus ratio (microns3 x 10(3) for both fibre types; the mean ratios of 39 +/- 3 and 12 +/- 1, were 60% and 36% of control means for the plantaris fast and soleus slow fibres, respectively. These results indicate that following hindlimb suspension atrophy of muscle fibres the myonuclei numbers remain constant or increase and, hence, the effective cytoplasmic-to-myonucleus ratio is decreased. Further, the decreased changes are significantly greater in soleus slow than plantaris fast fibres.

Animals↗
PubMed1995

Going through the motions: the ethics of process.

This article takes the position that the current ethic of nursing is inadequate. It is limited to an ethic of process. This ethic limits the discipline of nursing to process-oriented activities, including research and the clinical nursing process. These processes are not, however, unique to nursing but are shared by all professional disciplines. Nursing will continue to be insufficient without the development of structure or expert clinical knowledge accompanied by an ethic of accountability.

Curriculum↗
PubMed1995

Sarcolemmal disruption in reloaded atrophic skeletal muscle.

The purpose of this study was to determine whether reloading of atrophied skeletal muscle after 28 days of hind-limb unloading (HU) would produce significant sarcolemmal membrane disruption before frank necrosis. Soleus and plantaris muscles were atrophied by HU. Adult female Wistar rats (N = 13) were killed at 28 days of unloading and 4 and 7 days of reloading after HU. Rat serum albumin was used as a marker for muscle fiber disruption. Dark intracellular staining with horseradish peroxidase-conjugated anti-rat serum albumin antibody was interpreted as evidence of membrane rupture. There was a significantly different time course of disruption between plantaris and soleus muscles, with a negative correlation between cell size and occurrence of disruption. Fourteen percent of plantaris fibers were wounded after HU, peaking at day 4 of reloading (20% of cross-sectional area). Soleus demonstrated disruption only on reloading peaking in severity at day 7 (14% of fibers). It was demonstrated that sarcolemmal disruption due to atrophy and reloading does not always progress to necrosis and degeneration by the 7th day of recovery.

Animals↗
PubMed1995

Spatial patterns of fiber types in atrophied skeletal muscle.

This study examined the spatial distributions of different fiber types in the soleus muscle of control rats and in rats subjected to hindlimb unloading for 28 days. The frequencies with which muscle fibers of one type were adjacent to each other and to fibers of other types were tabulated and compared to expectations generated from Monte Carlo simulations. In the normal rat, there is a tendency for Type I fibers to avoid adjacency with each other, a tendency that persisted in the hindlimb-suspended group, despite the substantial shrinkage in size of Type I fibers. We conclude that this treatment, unlike neurogenic pathologies, does not cause any remodeling of the adjacency relations of fibers.

Animals↗
PubMed1995

A physiologic method for monitoring premature infants.

Instrumentation capable of handling 12 continuous hours of nine-channel real-time physiologic data sampled at 10Hz was needed to test within and between subject variability and preterm infant responses to skin-to-skin contact with the mother. A review of basic electrical components, electrical principles related to physiologic monitoring, and electrophysiology concepts generic to physiologic monitoring is presented. The development, specifications and applications of a new instrument to monitor premature infant cardiorespiratory adaptations are discussed.

Electrophysiology↗
PubMed1994

Cytoplasm-to-myonucleus ratios and succinate dehydrogenase activities in adult rat slow and fast muscle fibers.

The relationship between myonuclear number, cellular size, succinate dehydrogenase activity, and myosin type was examined in single fiber segments (n = 54; 9 +/- 3 mm long) mechanically dissected from soleus and plantaris muscles of adult rats. One end of each fiber segment was stained for DNA before quantitative photometric analysis of succinate dehydrogenase activity; the other end was double immunolabeled with fast and slow myosin heavy chain monoclonal antibodies. Mean +/- S.D. cytoplasmic volume/myonucleus ratio was higher in fast and slow plantaris fibers (112 +/- 69 vs. 34 +/- 21 x 10(3) microns3) than fast and slow soleus fibers (40 +/- 20 vs. 30 +/- 14 x 10(3) microns3), respectively. Slow fibers always had small volumes/myonucleus, regardless of fiber diameter, succinate dehydrogenase activity, or muscle of origin. In contrast, smaller diameter (< 70 microns) fast soleus and plantaris fibers with high succinate dehydrogenase activity appeared to have low volumes/myonucleus while larger diameter (> 70 microns) fast fibers with low succinate dehydrogenase activity always had large volume/myonucleus. Slow soleus fibers had significantly greater numbers of myonuclei/mm than did either fast soleus or fast plantaris fibers (116 +/- 51 vs. 55 +/- 22 and 44 +/- 23), respectively. These data suggest that the myonuclear domain is more limited in slow than fast fibers and in the fibers with a high, compared to a low, oxidative metabolic capability.

Animals↗
PubMed1993

Alterations in skeletal muscle related to impaired physical mobility: an empirical model.

The objective of this investigation was to study impaired physical mobility and the resulting skeletal muscle atrophy. An animal model was used to study morphological adaptations of the soleus and plantaris muscles to decreased loading induced by hindlimb suspension of an adult rat for 7, 14, and 28 consecutive days. Alterations in weight, skeletal muscle growth, and changes in fiber type composition were studied in synergistic plantar flexors of the rat hindlimb. Body weight and the soleus muscle mass to body mass ratio demonstrated significant progressive atrophy over th 28-day experimental period with the most significant changes occurring in the first 7 days of hindlimb suspension. Hindlimb suspension produced atrophy of Type I and Type IIa muscle fibers as demonstrated by significant decreases in fiber cross-sectional area (micron 2). These latter changes account for the loss of contractile force production reported in the rat following hindlimb unloading. When compared to traditional models of hindlimb suspension and immobilization, the ISC model produces a less severe atrophy while maintaining animal mobility and health. We conclude that it is the preferred animal model to address nursing questions of impaired physical mobility.

Adaptation, Physiological↗