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Biomedical subjects

W M Fowler

Publications and source records attributed to W M Fowler.

At least 37 records · Page 2Linked to original sources
PubMed1987

Upper vs lower extremity functional loss in neuromuscular disease.

Functional rating scales have been developed for evaluation of upper extremity (UE) and lower extremity (LE) function in Duchenne muscular dystrophy (DMD). The Vignos scale is accepted for LE function and the Brooke scale for UE evaluation. The assumption that UE functional loss parallels LE loss has never been tested. Furthermore, there are no studies examining the relationship between UE/LE strength. This study tests the hypothesis that UE/LE strength and functional losses are parallel in DMD and other neuromuscular disorders. Vignos grades, Brooke grades, and manual muscle test scores were determined for 27 patients with DMD, 10 patients with fascioscapulohumeral muscular dystrophy (FSH), 24 patients with myotonic muscular dystrophy (MMD) and 29 patients with other (Becker's dystrophy and limb-girdle syndrome) proximal myopathies (PM). Spearman correlation coefficients were calculated for UE vs LE functional grade and strength scores and subjected to significance analysis. While all correlations were statistically significantly different from zero (p less than 0.01), all were also significantly different from one (p less than 0.01), none representing perfect equivalence. Coefficients of determination indicated that a maximum of 86% (FSH) of variation in UE rank could be explained purely by observing LE rank. While there is a significant relationship between UE/LE strength and functional grade, these measurements were not found to be entirely equivalent. Therefore, while measures of lower body function or strength might be used as a substitute for UE measurements in drug trials in which global effects are expected, the two measurements are not equivalent when evaluating an individual's clinical status.

Child↗
PubMed1987

Upper extremity functional rating for patients with Duchenne muscular dystrophy.

The corresponding deterioration of upper extremity strength and functional capability with increasing age and the relationship between average strength and function were evaluated in 28 boys with Duchenne muscular dystrophy (DMD). Manual muscle testing (MMT) was used to evaluate strength and the Brooke upper extremity grading scale to rate upper extremity function. Mean MMT was found to relate to age in logarithmic fastion, ie, a 1% increase in age led to a 0.9% decrease in mean MMT. Functional grade (FG) related to age in a more complex fashion, revealing three groups based on age: under age 10, all in FG 1; between ages 10 and 13, concentration in FG 2 through 4; and over age 13, eight of ten in FG 5. Regression analysis did not contribute further useful information. Finally, mean MMT was found to be highly significantly related to FG. The plot of mean MMT against FG revealed an S-shaped curve, with rapidly rising functional grade once an average upper extremity strength of 4w was reached. The Brooke scale appears to be useful in describing upper extremity function among DMD patients, although it may reflect a three-grade rather than a six-grade discrimination capability. In describing the natural history of DMD, this scale demonstrates a pattern of rapid functional deterioration during the early adolescent years. This functional deterioration apparently takes place when the decline in strength reaches a threshold which cannot be compensated by muscle substitutions. At that time function deteriorates along a relatively rapid but undefined course.

Adolescent↗
PubMed1985

Serotonin-induced contractile and structural changes in fast and slow skeletal muscles in mice.

The effects of serotonin on the contractile properties of the soleus and extensor digitorum longus muscles in mice were studied after chronic intraperitoneal administration with and without a recovery period, and compared to contractile studies of the same muscles performed after acute administration of serotonin. A curarized in vitro preparation of both muscles was used throughout for the contractile studies. In addition, structural changes were studied in the chronic preparations. Chronic serotonin administration produced histologic changes in type 1 and 2A fibers and a reduction in twitch and tetanic tension and the rate of twitch and tetanic tension development limited to the slow (aerobic) soleus muscle. Acute in vitro administration of serotonin altered the contractile properties of both soleus and extensor digitorum longus muscles with the latter being more involved. The effects of chronic serotonin administration appear to be primarily related to ischemia while the effects of acute administration appear to be mediated by direct, nonvascular action on skeletal muscle.

Animals↗
PubMed1984

Effect of pentobarbital on contractility of mouse skeletal muscle.

Pentobarbital is a hypnotic drug commonly used as anesthesia for in vivo studies in various animals. A direct effect of pentobarbital on the central nervous system and skeletal neuromuscular junction has been known for at least 30 years. A recent study using single fiber preparations from amphibian muscles indicated a significant acute and direct effect on muscle contractility at drug concentrations within the anesthetic range. The present study using whole muscles from mice demonstrated a similar augmentation of twitch tension and rate of tension development whereas tetanic tension was reduced by this drug at similar concentrations. In addition, most time parameters of contraction were prolonged. It is of interest that the slow (oxidative) muscles were considerably more sensitive to pentobarbital than the fast (primarily anaerobic) muscles. We suggest that pentobarbital should not be used as the anesthetic agent for in vivo studies of other interventions when conclusions are based on changes in muscle contractility.

Animals↗
PubMed1984

Psychometric evaluation in myotonic muscular dystrophy.

Systematic psychometric evaluations were performed in 16 patients with myotonic muscular dystrophy (MMD). All patients received the Wechsler Adult Intelligence Scale-Revised and Wechsler Memory Scale-1. In addition, 13 patients received the Reitan-Halstead Neuropsychological Test Battery (R-H), including the Aphasia Screening Test. Despite the high reported incidence of mental retardation in MMD, none of our pilot population showed mental retardation. However, 5 of the 13 patients showed evidence of possible organic mental dysfunction on the R-H. Problems in previous studies which could explain these discrepancies include the following: (1) small sample size, (2) studies limited to young children, and (3) a complete lack of systematic psychometric data in the previous reports. Systematic cooperative studies are suggested to elucidate the degree and type of cognitive involvement in MMD.

Adolescent↗
PubMed1983

Slowly progressive proximal weakness: limb-girdle syndromes.

Many diseases of the motor unit result in slowly progressive limb-girdle weakness. Difficulty in diagnosis arises because many of these disorders share a similar genetic pattern, and some are heterogeneous. Most of the symptoms have such a broad range that they are of limited diagnostic value, and physical findings, even within families, often cover a wide spectrum. With a few exceptions, laboratory data are often of only limited diagnostic assistance. This review documents the need for a careful genetic, clinical, and laboratory evaluation in these disorders, affirms the importance of clinical observation, and identifies the most dependable clinical and laboratory findings.

Adolescent↗
PubMed1982

Rehabilitation management of muscular dystrophy and related disorders: II. Comprehensive care.

Management of patients with motor unit diseases is now more aggressive than in the past. Most physicians and therapists now believe that it is important to preserve maximal function as long as possible. Treatment should be prospective to inhibit deformity, prolong independent ambulation, and maximize functional capabilities. Management can best be carried out by a multidisciplinary approach to comprehensive care, and should consider the entire needs of the patient. Major goals are early diagnosis and establishment of a rehabilitation plan, maintenance of ADL and ambulation as long as possible, anticipation of complications, and the development of a program of prevention and supportive counseling to patient and family.

Ambulatory Care↗
PubMed1982

Rehabilitation management of muscular dystrophy and related disorders: I. The role of exercise.

When evaluating the effect of a modality such as exercise, maturation in children, the rate of progression of the disease, and the degree of weakness should be considered. The two major factors critical in producing overwork weakness are the degree of weakness at the time the exercise program is started and the intensity of the exercise training program. Exercise therapy is apparently not harmful and may be beneficial in patients with motor unit diseases if it is started early in the course of the diseases when muscle fiber degeneration is minimal, and is carried out at submaximal levels.

Animals↗
PubMed1980

Fast and slow skeletal muscles: contractility evaluated by paired stimuli in mice.

The purpose of this study was to evaluate a technique for in vitro study of mouse skeletal muscle, to determine if paired stimuli would allow estimation of new time parameters of contraction. Conventional tension measurements were obtained, plus the time measurements from the paired stimulus studies. The muscles were also subjected to fatigue by repetitive tetanization. A fast muscle (extensor digitorum longus or plantaris) and a slow muscle (soleus) were studied in each preparation. Studies were conducted at physiologic (35C) and at nonphysiologic (20C) temperatures. Data obtained indicate that this isometric in vitro method allows subdivision of results into 3 categories of effect due to treatment related to the functional muscle compartments: 1) chronotropic-excitation contraction coupling mechanisms, 2) inotropic- contractile elements, and 3) metabolic (fatigue)-energy supply mechanisms. When results as 20C were compared with physiologic temperature, a negative chronotropic effect was observed for all parameters in all 3 muscles. A positive inotropic effect was observed for twitch with no change or a negative effect for all other tension parameters. The lower temperature produced slight protection from fatigue. Models were developed to demonstrate how data from isometric studies fit the original concepts developed using isotonic methods. The model and method should prove of value in detecting the acute effect of drugs or of other therapy imposed on skeletal muscles.

Animals↗
PubMed1980

Fast and slow skeletal muscles: effect of secobarbital on contractility of muscles from mice.

In vitro studies were performed on fast and slow muscles from mice to determine if secobarbital sodium (SCB) has a direct effect on muscle contractility. All preparations were curarized and stimulation was direct. After baseline studies, SCB was added to the muscle bath in 1 of 4 concentrations-10, 20, 100 and 200 microgram/ml. Tetanic tension was reduced for both muscle types at SCB concentrations greater than or equal to 20 microgram/ml, and loss was progressive with increasing dose. In contrast, twitch tension (P) was increased by SCB at the 2 higher concentrations. The increase in P was due to an increase in rate of tension development plus prolongation of the time parameter (duration) of the twitch. Fatigue was accelerated by SCB for both muscle types. The results indicate that SCB has a direct and similar effect on fast and slow skeletal muscles. The probable sites of action of the drug are the excitation contraction coupling mechanisms and the mechanisms for energy production and/or utilization.

Animals↗
PubMed1977

The effect of age on the nucleic acid content of slow- and fast-twitch muscle in normal and dystrophic mice and their litter mates.

RNA, DNA, and NCP content were measured in fast- and slow-twitch skeletal muscle of normal and dystrophic mice (HDM) and their littermates at ages 4 through 29 weeks. In normal and litter mate mice RNA and DNA content were far greater in the soleus than in the gastrocnemius while the RNA/DNA ratio and NCP content were greater in the gastrocnemius. In dystrophic mice, however, the differences between nuleic acid content of the 2 muscles were far less, apparently due to a proportionately higher content in the dystrophic gastrocnemius. Due to a proportionately lower ratio in the gastrocnemius, dystrophic RNA/DNA ratios for the 2 muscles were essentially the same. Age had a marked effect on the nucleic acid content of both muscles in all 3 mice types but to varying degrees. In the soleus, RNA and DNA content rapidly decreased until 9 to 10 weeks of age followed by a gradual decline. Soleus RNA/DNA ratios showed little change with age except in the HDM mice in which there was a significant overall decline. In the gastrocnemius, RNA content followed the same pattern but with a smaller decline in the younger ages. Age had no affect on DNA content in the normal gastrocnemius, but there was significant decline in the HDM gastrocnemius. RNA/DNA gastrocnemius ratios showed marked fluctuations in both normal and dystrophic mice but did not appear to be affected by age.

Age Factors↗
PubMed1976

Exercise effect on contractile properties of skeletal muscle in mouse muscular dystrophy.

The purpose of this study was to determine the effect of a high repetitive exercise program, treadmill running, on the tetanic tension and rate of tension development of the slow twitch soleus muscle of normal plus dystrophic mice and their littermates. The exercise program used would be considered to be of mild intensity since it failed to produce any detectable histochemical or biochemical changes. In the noninvolved normal and littermate mice, there was no difference in maximum tetanic tension between the exercised and nonexercised control groups. In the normal mice (eight weeks of age), there was a significant decrease in rate of tension development for those exercised for five weeks compared to nonexercised controls. In littermate mice (seven weeks old) exercised for a four-week period, there was also a significantly lower rate of tension development compared to their nonexercised controls. In dystrophic mice (seven weeks old) exercised for only one to two weeks, there was significantly lower tension as well as rate of tension developed for the exercised mice when compared to nonexercised dystrophic mice. In dystrophic mice (six weeks old) exercised for one to two weeks, there was no difference in tension or rate of tension development when compared to nonexercised controls. In both six and seven-week-old littermate mice, also exercised for one to two weeks, this reduction in tension and rate of tension development did not occur. The average life span for the dystrophic mice used in this study is about 30 weeks. Of the nine exercised dystrophic mice scheduled for study at eight weeks, only one survived, suggesting that even the mild exercise used might have shortened their life expectancy.

Animals↗
PubMed1976

Fast and slow skeletal muscles: simultaneous in vitro study.

Simultaneous study of the function of fast and slow twitch skeletal muscles in the same in vitro preparation has obvious advantages. Equipment, method and technique are described for study of the soleus (slow) and extensor digitorum longus (fast) muscles from the mouse, and the problems involved in preparing and standardizing these studies are discussed. For nearly maximum function to be obtained from both muscles, careful attention must be given to the stimulus parameters used. Three separate studies were necessary to determine the appropriate stimulus duration, frequency and rest interval between the stimulus trains. The results indicate that for study of tetanic tension and rate of tension development of these muscles from the C57 NAB strain of mice at 20C the most satisfactory stimulus parameters are : duration 2 msec, frequency 100 pulses per second and duration of the stimulus train 700 msec. Rest interval between stimulus trains was two minutes as problems developed with rest intervals less than two minutes or greater than four minutes.

Animals↗