Carcinoid myopathy. Serotonin-induced muscle weakness in man?

A myopathy, which improved with cyproheptadine hydrochloride therapy, developed in a patient with carcinoid syndrome of ten years' duration. Biopsy examination revealed advanced atrophy of type II muscle fibers, with type I fiber preponderance. Many of the small fibers had degenerated. Carcinoid myopathy may be due to excess circulating serotonin.

The pathology of the muscle spindle in myasthenia gravis.

Abnormalities in the morphology and motor innervation of the muscle spindles are described in 4 autopsied cases of myasthenia gravis. There were changes consistent with motor denervation in 5 of 118 spindles examined in sectioned material. In 65 teased, silver-impregnated spindles there was proliferation of the fusimotor innervation due to axonal sprouting occurring in the endings themselves. Motor end-plates on the intrafusal muscle fibres showed "dystrophic" changes similar to those previously described in extrafusal muscle in this disease. The sensory innervation was normal. The possible signifance of these findings is discussed.

The pathology of the muscle spindle in Duchenne muscular dystrophy.

Muscle spindles have been studied in 7 autopsied cases of Duchenne muscular dystrophy. The autopsies of 2 boys of similar age who died without known neuromuscular disease were used as controls. The abnormalities found consisted of degenerative changes, atrophy and loss of intrafusal muscle fibres, thickening of the spindle capsule and widening of the periaxial space. In some very severely affected muscles there was evidence that spindles were destroyed in the course of the disease. Statistical comparison of these observations was made between the pathological and normal material. The muscle spindle innervation appeared normal in sectioned material. Teased preparations were not available for study.

Administrative issues in the management of a sports medicine program.

Sports medicine is a subspecialty of medicine which has recently gained prominence in this country. It is usually practiced in conjunction with a specific program of sports medicine in an institutional setting, such as a university. This article describes the integration of sports medicine and the department of athletics at Yale University. The athletic medicine department, as it is called, treats both the injuries and other medical problems of students participating in the organized athletic programs, be they intercollegiate or intramural, which are organized by the University. Problems that arise both medically, such as when to play an injured player, and administratively, such as who should supervise trainers, are discussed. Guidelines are given for choosing the director of this program, as are examples of how to deal with problems between the physicians and the coaches.

Abnormal intrafusal muscle fibres in myotonic dystrophy: a study using serial sections.

Studies of the extent and complexity of intrafusal muscle fibre splitting in myotonic dystrophy have been carried out in three spindles obtained at muscle biopsy, and in nine spindles found in the lumbrical muscle of a case that came to necropsy. It is suggested that splitting, due to mechanical stresses, leads to a regenerative response in the separated fragments.

Sensory innervation of baboon muscle spindles.

The number and distribution of primary and secondary sensory endings has been studied in 52 de-efferentated baboon muscle spindles and the axon diameters of the afferent fibres innervating these endings have been measured. Each spindle contained a single primary sensory ending; most of these endings were supplied by a single afferent nerve fibre. Each primary sensory ending consisted of a multi-branched network distributed on both nuclear bag and nuclear chain fibres. Beaded sensory terminals were prominent in the central part of the ending. Eighty one secondary endings were found in 45 spindles (87% of the number of spindles remained). Of these endings, 70% were found in the S1 position, 25% in the S2 position and 4% in the S3 location. The afferent axons supplying the most equatorial of these endings were of thicker mean diameter than those supplying the most polar endings. In addition, the juxta-equatorial secondary endings were similar in form, although less regularly organized than the primary endings. The more polar secondary endings rarely fromed terminal sensory enlargements and usually took the form of a fine spray of unmyelinated branches. A non-parametric statistical comparison of physiological and anatomical data in baboon spindles has suggested that the demarcation criteria for separation of primary and secondary spindle afferents, using conduction velocity, should be modified. It is suggested that afferent fibres of conduction velocity less than 60 m/sec should be classified as secondary afferents, and fibres of conduction velocity greater than 72 m/sec should be classified as primary afferents.