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Biomedical subjects

J F Ditunno

Publications and source records attributed to J F Ditunno.

At least 91 records · Page 5Linked to original sources
PubMed1986

Overwork effect on partially denervated rat soleus muscle.

The purpose of this study was to assess the effect of overwork induced by synergistic tenotomy on the muscle weight (MW) and isometric tetanic tension (Po) of the partially denervated rat soleus muscle. Forty-nine young adult male Sprague-Dawley rats were divided into six groups (n = 5 to 9): normal control (N), normal synergistically tenotomized (N-ST), L4 denervated control (L4), L4 denervated synergistically tenotomized (L4-ST), L5 denervated control (L5), and L5 denervated synergistically tenotomized (L5-ST). Bilateral L4 or L5 root transections produced partial denervation. To yield soleus muscle overwork the gastrocnemius and plantaris muscles were bilaterally tenotomized in all ST groups at the time of denervation. The soleus MW and Po were examined seven days following denervation and tenotomy. Compared to their respective controls, there was increased MW in the N-ST (43.5%, p less than 0.01) and the L4-ST (38.6% p less than 0.01) groups. The L5-ST group showed no significant change in MW compared to the L5 group. Tetanic tension was increased only in the N-ST group. The L4-ST and L5-ST groups did not show any change in Po compared to their respective controls. Despite marked denervation, the L5 group did not show any atrophy as compared to the N group, suggesting passive stretch of the denervated muscle fibers, hypertrophy of the innervated muscle fibers and peripheral sprouting prevented the loss of MW due to denervation. Overwork in this markedly denervated group could not produce any increase in the MW or Po.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Muscle atrophy and histopathology of the soleus in 6-mercaptopurine-treated rats.

This study was conducted to examine the histochemical changes occurring due to neonatal 6-mercaptopurine (6-MP) treatment (2 mg/kg, sc, between 2 and 22 days after birth) in the slow-twitch muscle (soleus) of adult male and female rats. At 6 months of age, the control and the 6-MP-treated rats were evaluated for the sciatic nerve conduction to the soleus and for the soleus atrophy and histopathology of the type I (slow-twitch) and type II (fast-twitch) muscle fibers. Compared to the normal controls, the 6-MP-treated male and female rats showed similar sciatic nerve conduction to the soleus. However, there was a significant muscle atrophy (57-60%, P less than 0.01) and a decrease in fiber areas of the type I (42-54%, P less than 0.05) and type II (41-71%, P less than 0.01) fibers. The number of type II fibers declined significantly (7.4-14.8%, P less than 0.05). It is proposed that the soleus muscle atrophy and histopathology in 6-MP-treated rats is unrelated to nerve conduction defects and may be related to growth inhibition caused by an interference of the drug during normal differentiation of muscle fibers.

Adenosine Triphosphatases↗
PubMed1984

Recovery of reinnervating rat muscle after cast immobilization.

We evaluated the recovery of the reinnervating rat plantar flexor muscles after different periods of casting and then decasting the lower extremities. Four groups of 4-month-old, female Wistar rats underwent bilateral crush-denervation of the sciatic nerve at the sciatic notch. Two weeks after nerve crush, the hind legs of three groups of rats were immobilized with bilateral casts at the knee and ankle joints and the fourth group was a control group. Of the three casted groups, one was mobilized after 1 week and another group after 3 weeks of casting. The third experimental group remained casted until the end of 6 weeks. Six weeks after the nerve crush, all groups were evaluated for muscle weights of the soleus, plantaris, and gastrocnemius; absolute amounts of the myofibrillar, sarcoplasmic, and stromal proteins in the gastrocnemius; the fiber diameters and percent composition of type I and type II fibers in the soleus and plantaris; and the isometric contractile properties of the soleus muscle. Compared with the denervated control group, the experimental groups revealed the following: (i) Four weeks of casting caused a reduction in wet weight (range 30.6 to 40.4%, P less than 0.01) in the soleus, plantaris, and gastrocnemius muscles. Decasting led to an earlier recovery of the soleus than of the plantaris and gastrocnemius muscles. (ii) The myofibrillar protein returned to control values with 3 weeks of decasting but the stromal protein remained significantly elevated and the sarcoplasmic protein significantly depressed regardless of the period of mobilization. (iii) Except for the type I fibers in the plantaris, the remainder of the muscle fibers in the soleus and plantaris decreased in size due to casting. Only the type I muscle fibers of the soleus increased in size with longer periods of mobilization. (iv) Four weeks of casting significantly altered the maximum isometric twitch tension (-42.3%), contraction time (+17.1%), maximum tetanic tension (-38.1%), and half-fatigue time (+40.5%) in the soleus. The reinnervating soleus muscle appears to recover from the effects of casting sooner than the plantaris or gastrocnemius muscles.

Animals↗
PubMed1984

Immobilization hypercalcemia in acute spinal cord injury treated with etidronate.

Hypercalcemia developed in a 30-year-old C5 quadriplegic six months after he received a gunshot wound in the cervical spine. Short-term treatment consisted of fluids and diuretics, but conventional drug therapy for long-term maintenance of normocalcemia was not effective. A regimen of etidronate disodium was then instituted, which resulted in normocalcemia. When use of this drug was discontinued at intervals during the therapy, the hypercalcemia recurred. The patient's condition was maintained on the etidronate regimen until full mobilization occurred, at which time the drug therapy was discontinued and normocalcemia persisted. This case represents, to our knowledge, the first reported success with the use of etidronate in the treatment of hypercalcemia in the immobilized patient with acute spinal injury.

Acute Disease↗
PubMed1983

Compensatory hypertrophy of the soleus in tumor-bearing rats.

Compensatory hypertrophy of the rat soleus was compared between normal rats (N) and rats bearing a non-metastasizing mammary tumor (TB). Two weeks after the tumor inoculation, introduced subcutaneously on the midline of the upper back, the two groups of rats underwent unilateral tenotomy of the plantaris and gastrocnemius muscles to induce functional overload or compensatory hypertrophy of the soleus. One week later, the body weight (BW), wet muscle weights (MW), percent of Type I (slow-twitch) and Type II (fast-twitch) muscle fibers and contractile parameters of the isometric twitch (Pt) and tetanic (Po) tensions were evaluated. The TB animals did not show any signs of cancer cachexia. The sham-operated control soleus muscles of the two groups were similar in wet MW, maximum isometric Pt and Po. The latent period (LP), the contraction time (CT), the half relaxation time (HRT) and the number of Type I (slow-twitch) fibers were increased significantly. The hypertrophied muscles in the N and TB rats showed significant declines in the maximum isometric Pt, compared to their respective controls. These data suggest that the compensatory hypertrophy of muscle is expressed similarly in both the normal and tumor-bearing rats but that it interferes with the generation of isometric twitch tension in the muscle.

Adaptation, Physiological↗
PubMed1983

Exercise therapies in peripheral neuropathies.

The treatment of peripheral neuropathies should be aimed at maintaining the range of motion of the joints, re-educating the patient in skilled activities and optimizing the recovery of strength. Many techniques have been described to substitute for, to strengthen and to improve the function of residual innervated muscle; however, not all of these techniques are of unquestioned value. Specifically, electrical stimulation does not appear to enhance reinnervation of totally denervated muscle. Similarly, overstretching weakened muscle may impair the use of paretic muscle. Because overwork may damage partially denervated muscle, brief isometric or isotonic contractions may be more beneficial for increasing strength than a program of habitual exhausting activities.

Cold Temperature↗
PubMed1983

Acetylcholine sensitivity and fibrillation potentials in electrically stimulated crush-denervated rat skeletal muscle.

Juxtamuscular electrodes were implanted unilaterally in six groups of adult female Wistar rats to evaluate the effect of chronic electrical stimulation (ES) during denervation and reinnervation of the rat soleus muscle. Two weeks later, the animals underwent bilateral crush-denervation of the sciatic nerve at the sciatic notch. Six additional groups served as normal controls. The soleus muscles in the crush denervated and control groups were stimulated unilaterally with a 4mA, 4msec duration current given at 10Hz continuously 8 hours each day for 5, 10, 15, 20, 25 or 30 days. At the end of each period, the soleus muscles were evaluated for the muscle weights, acetylcholine (ACh) sensitivity and fibrillation potentials (FPs). The normal muscles were unaffected by the stimulation. The denervated-stimulated soleus muscles were heavier at 10 days (p less than 0.05) and had fewer FPs after 5 to 15 days (p less than 0.01) of electrical stimulation than their matched denervated controls. The ACh sensitivity throughout the experimental period and the fibrillatory activity from 20 to 30 days post-crush were similar in the denervated and the denervated-stimulated muscles. In conclusion, ES reduced the degree of atrophy and the number of fibrillations of the soleus muscle in the denervation stage. However, it neither enhanced nor impaired the reinnervation of muscle.

Acetylcholine↗
PubMed1982

Changes in thromboxane B2 and 6-keto-PGF1 alpha after direct electrical stimulation of the denervated rat gastrocnemius1,2.

Radio-immunoassay was used to measure the amounts of Thromboxane B2 (TXB2) and 6-keto-PGF1 alpha produced in the gastrocnemius muscles of rats after denervation and direct electrical stimulation (2-4 mA intensity and 4 msec duration pulses given at 10 Hz continuously, 8 hours each day for 14 days). Compared to the normal control side, the normal-stimulated, the denervated control and the denervated-stimulated muscles, all indicated increases in the content (ng/g muscle) of TXB2 (120-155%, P less than 0.01) and 6-keto-PGF1 alpha (90-10 7%). This study suggests that electrical stimulation as well as denervation may lead to an elevation of these prostanoids.

6-Ketoprostaglandin F1 alpha↗
PubMed1982

Muscle fiber types.

This review describes muscle fiber types based on their histochemical, ultrastructural, biochemical, and physiologic properties. Reportedly the speed of muscle fiber contraction is directly proportional to relative myosin ATPase activity (at pH 9.4) while fatigability relates to relative oxidative capacity. Type I fibers have low ATPase activity (at pH 9.4), are slow twitch, have high oxidative and low glycolytic capacity, and are relatively resistant to fatigue. Type IIA fibers have high myosin ATPase activity (pH 9.4), are fast twitch, have high oxidative and glycolytic capacity, and are relatively resistant to fatigue. Type IIB fibers have high myosin ATPase activity (pH 9.4), are fast twitch, have low oxidative and high glycolytic capacity, and fatigue rapidly.

Adenosine Triphosphatases↗
PubMed1982

Physical activity and inactivity influences on 14C-leucine incorporation in reinnervated rat gastrocnemius.

The influence of activity and inactivity in reinnervated gastrocnemius muscles of adult rats was evaluated by measuring muscle mass, sarcoplasmic proteins (SP), myofibrillar proteins (MP), and 14C-leucine incorporation. Both sciatic nerves were crushed in 18 adult female Wistar rats, 6 of which were exercised daily on a 35% grade treadmill at a running speed of 27 m/min, 6 others underwent bilateral cast-immobilization of the ankle, knee, and hip joints at 90 degrees, and 6 were kept as sedentary controls between 2 and 6 weeks after denervation. During this period, all animals received daily an injection of 0.2 ml of 14C-leucine (sp. activity 51.4 muCi/mM). The exercised rats had similar muscle mass, but significantly increased in both MP and 14C-leucine incorporation, when compared to the sedentary rats. In contrast, the cast-immobilization group showed significant decreases in muscle weight and 14C-leucine incorporation in SP. These results suggest that activity enhances the apparent synthesis of MP in reinnervating muscles, but does not indicate that inactivity interferes with or limits the process of reinnervation by impeding the synthesis of SP or MP.

Animals↗
PubMed1982

Reinnervating rat skeletal muscle: effect of 35% grade treadmill exercise.

To determine the effect of 35% grade treadmill running on reinnervating rat skeletal muscle, adult rats were exercised for 1 hour on a 35% grade motorized treadmill, at a speed of 27m/min, once and twice daily, 5 days a week from the 3rd to the 6th week after sciatic nerve crush. Compared to the crush denervated control, the crush-denervated-twice exercised group decreased in the content of sarcoplasmic proteins (15.2%, p less than 0.05), and in the contraction time of the soleus (8.9% p less than 0.05). The percentage of type II fiber types in the plantaris increased 15% (p less than 0.05) in the once and 10% (p less than 0.05) in the twice daily exercised group. The findings of this study suggest that treadmill training performed during reinnervation did not cause muscle damage and may have increased the "fast" type muscle properties in the rat skeletal muscle.

Animals↗
PubMed1982

Subarachnoid-pleural fistula in traumatic paraplegia.

Subarachnoid-pleural fistulas caused persistent pleural effusion in 2 patients with traumatic paraplegia. The fistulas were diagnosed by myelography and radioisotope scan. Most of the previously reported cases of this rare entity have been treated by operative closure of the fistula. Both of the reported patients recovered: one underwent insertion of chest tubes to promote drainage and the other had no specific therapy. The authors believe conservative treatment should be attempted before surgery is considered.

Accidents, Aviation↗
PubMed1981

Response of type I fibers to weight lifting in rat plantaris.

The purpose of this histochemical study was to determine the effect of weight lifting exercise training on the muscle fibers in 2 muscle regions of the rat plantaris. Adult female Wistar rats were trained to carry weights up to 150 gm on their backs, up a 50 degrees incline, for a period of 6 weeks. A comparison between the exercised and control groups showed no significant muscle hypertrophy or change in the number of fibers. Only the smallest muscle fibers, which are located predominantly in the superficial region of the plantaris, showed a significant increase (19.6%, p less than 0.01) in diameter. The data suggest that the smallest muscle fibers, in the superficial region of the plantaris in this weight lifting training program, were exercised out of proportion to their usual activity and responded to the stress of the activity by enlarging.

Animals↗
PubMed1981

Contractile properties of reinnervating skeletal muscle in the rat.

The purpose of this study was to determine the isometric twitch tension (Pt), isometric tetanic tension (Po), and twitch contraction time (Ct) of the reinnervating rat soleus and plantaris muscles. Six groups of adult female Wistar rats (200 to 225 gm BW) underwent bilateral sciatic nerve crush at the sciatic notch, while another 6 groups were kept as sham-operated normal controls. The contractile properties of the muscles from the normal and crush-denervated groups (n=6-9) were determined in vitro weekly, at 0, 1, 2, 3, 4, 5, and 6 weeks, post-nerve crush. The muscle were equilibrated in a polyglass cell in oxygenated Ringer's solution at pH 7.2 at 34-35 C. The muscles were field stimulated at optimal length (Lo) to produce maximal Pt, using 15-20 v, 5 amp current, at 0.2 Hz for 1 msec duration. Following twitch determinations, the muscles were tetanized at 200 Hz. All tension values were expressed per unit area of the muscle. The respective control tension per area values for the soleus and plantaris were: Pt, 3.3 +/- 0.4 gm, 5.9 +/- 0.4 gm; Po, 20.7 +/- 5.1 gm, 21.8 +/- 4.8 gm, while the Ct values for the soleus and plantaris were 37.6 +/- 2.1 msec and 16.3 +/- 1.1 msec, respectively. At 3 weeks post-nerve crush, the crush-denervated soleus Pt and Ct increased 40% and 33.6% respectively, and the plantaris 28.2% at 1 week after the nerve was crushed. Gradual recovery was noted in the Pt and Ct from the 4th to 6th weeks post-crush, while the Po began improving 1 to 2 weeks after denervation. The soleus Pt and Po appeared to be more dependent on neural control than the plantaris muscle. During reinnervation, the slow soleus and fast plantaris Ct were equally dependent on innervation. Reinnervation prompted changes in the Po, Pt, and Ct, suggesting that regenerating neurons promote a sequential emergence of normal contractility.

Animals↗
PubMed1980

Histochemical fiber type alterations secondary to exercise training of reinnervating adult rat muscle.

The purpose of this study was to evaluate the effect of exercise training on reinnervating rat muscle histochemistry. Adult female Wistar rats in 5 groups (1 control and 4 experimental) underwent bilateral sciatic nerve crush. The 4 experimental groups were exercised on a motorized treadmill at 35% grade and a speed of 27m/min once (groups J and L) or twice (groups K and M) daily, 5 days/week from the 2nd (groups J and K), and 3rd (groups L and M), to the 6th week after the crush. The exercise sessions lasted 1 hour. The fiber diameter and percent of type I and II fibers (weak and strong myosin ATPase reaction, pH .94) were evaluated in the soleus and superficial and deep regions of the plantaris muscles. Exercise training did not affect the fiber diameters. There was no change in the fiber type distribution in the soleus and superficial region of the plantaris. However, the percent of type II fibers increased significantly (p less than 0.05) in the deep region of the plantaris groups J, K, L and M bu 12%, 7%, 15% and 10%, respectively. This study indicated that exercise did not interfere with reinnervation and that there was an increase in the proportion of fibers with a strong myosin ATPase reaction in the deep region of the plantaris.

Adenosine Triphosphatases↗