The significance of ragged-red fibres in neuromuscular disease

The pathological significance of ragged-red fibres is uncertain. We have studied ragged-red fibres in the muscle biopsies of 3 adults; one with polymyositis and two with progressive external ophthalmoplegia. All the ragged-red fibres were Type 1 fibres. In two patients the mean diameter of the ragged-red fibres was significantly smaller than the unaffected Type 1 fibres. Some of these fibres showed features of regeneration, and others of degeneration. In the patient with polymyositis the mitochondria were proliferated and contained osmiophilic dense bodies; in the other two patients paracrystalline mitochondrial inclusions were prominent. These findings suggest that ragged-red fibres do not represent a single pathological process.     

室管膜下型灰质异位脑纤维结构连接的MR弥散张量成像研究

目的观察室管膜下型灰质异位（PNH）所发出白质纤维束的空间分布形式以及与正常脑组织的空间位置关系。方法8例以癫痫症状就诊的PNH患者经3．0T磁共振仪T1及T：加权成像诊断,并采集弥散张量成像数据。采用白质纤维束追踪技术,以异位灰质团块作为种子点,对异位灰质相连的白质纤维束进行描绘,并观察总结其空间分布模式及与其他大脑结构之间的关系。结果异位灰质白质纤维束有以下分布特点：①异位灰质均能发出自身的白质纤维,其中有4例表现为仅与位于同侧大脑半球的长联络纤维连接;3例除联络纤维外,还可见到其白质纤维参与对侧的胼胝体连接;6例可见到连接至皮层的弓状纤维;②结构连接空间模式与灰质异位所处位置有关,位于侧脑室前角旁的异位灰质发出的联络纤维主要分布于前方,位于侧脑室后角旁的异位灰质发出的联络纤维主要分布于后方,靠近胼胝体的异位灰质其自质纤维较易连接到对侧,靠近皮层的异位灰质较易发出弓状纤维与皮层相连。结论异位灰质不是孤立的结构,其可发出或长或短的白质纤维,并较广泛地与正常脑结构保持连接;其纤维连接分布的空间模式与异位灰质所处的位置有关。     

The histochemistry of very small muscle fibres in growing skeletal muscles

Serial sections of biceps femoris muscles from 10 rapidly growing pigs were reacted for succinate dehydrogenase (SDH) and myofibrillar adenosine triphosphatase (ATPase) and were stained with silver to delineate the endomysial boundaries of their muscle fibres. The histochemistry of very small fibres (less than 0.001 mm2) was similar to that of surrounding fibres with a normal diameter. Of the small fibres, 71.5% had strong ATPase, 27.5% had weak ATPase, 22% had strong SDH, 23.8% had intermediate SDH and 54.1% had weak SDH reactions. Corresponding values for surrounding fibres with a normal diameter were 87.9% with strong ATPase, 11.8% with weak ATPase, 35.1% with strong SDH, 14.5% with intermediate SDH, and 50.5% with weak SDH reactions. An appreciable number of small fibres were histochemically unrelated to any of their surrounding fibres: 11.0% for ATPase, 12.8% for SDH, and 5.5% for both ATPase and SDH. The cross-sectional shapes of small fibres were similar to those of their surrounding fibres. It was concluded that these small fibres were probably the tapered ends of intrafascicularly terminating muscle fibres rather than new muscle fibres formed by splitting.     

Observations on sensory and sympathetic function during intrathecal analgesia.

A dilute solution of procaine in glucose solution was injected by slow drip into the lumbar theca of patients to cause a differential block. Vasodilatation of the skin vessels of the lower limbs always occurred before any change in sensibility. The first changes in sensibility were inability to fell painful stimuli and warm stimuli; these two forms of sensibility were usually coextensive and occurred at the same time. When this was not so, either form of sensibility could be more extensively disturbed than the other. When warmth sensibility was removed, cold sensibility was either normal or diminished or cold stimuli caused non-thermal sensations such as non-thermal wetness or pressure. It is concluded that the nerve fibres signalling warmth are the smaller delta fibres or non-myelinated fibres or both. As two groups of investigators who recorded from the non-myelinated fibres in man found no non-myelinated fibres responding to cold, it is condluded that fibres signalling cold cover the same delta range as those signalling warmth, together with a proportion of larger delta fibres. When fibres subserving pain, warmth, and cold were blocked, tactile sensibility could be normal. It is concluded that, if there are tactile fibres in man in the smaller delta and non-myelinated ranges, their contribution to tactile sensibility is insignificant. It is also concluded that the pre-galglionic B fibres are the most susceptible of all fibres of the nerve roots to local anaesthetic agents. On two occasions, piloerection occurred when the pre-ganglionic sympathetic fibres were blocked. In two patients spontaneous itching occurred when all peripheral nerve fibres were blocked except large tactile fibres.     

Effects of activity in non-myelinated afferent fibres on the spinocervical tract.

Microelectrode recordings were made from axons of the spinocervical tract (SCT) in unanaesthetized decerebrate-spinal cats. Pure volleys in non-myelinated (C) cutaneous nerve fibres were obtained by DC-polarization block of conduction in the myelinated (A) fibres, and SCT cells were classified according to whether or not they were excited by C fibres. The effects of conditioning C responses in the SCT with A and C fibre input were examined, as were the effects of conditioning A fibre responses in the tract with C fibre inputs. The effects of stimulating descending systems in the cervical spinal cord on the C fibre-evoked responses of SCT cells were determined. SCT units with a slowly-adapting pressure-sensitive component in their receptive fields responded to cutaneous C fibres in addition to A fibres. Units which responded only to hair movement when the receptive field was stimulated mechanically were not excited by C fibres. Responses in SCT neurones produced by C fibres were profoundly inhibited by conditioning volleys in A fibres of both ipsilateral and contralateral cutaneous nerves and by activity in several descending systems. Conditioning with C fibres failed to affect the responses of SCT cells to either A or C fibres. It is concluded that cutaneous C fibres excite some SCT cells but have no other effect on transmission through this system. It is suggested that there are common inhibitory interneurones in the paths from descending systems and cutaneous A and C fibres to the excitatory input to SCT cells.     

Properties of mechanoreceptor afferent fibres in left inferior cardiac nerve

Single afferent fibres with receptive field in the heart chambers and great vessels were dissected from the thoracic sympathetic chain. The fibres were identified by the electrical stimulation of the left inferior cardiac nerve, which was left in continuity with the heart. Fifty-six percent of the afferent fibres from the left inferior cardiac nerve were spontaneously active, the rest was silent. The spontaneously active fibres with receptive field in the aorta or left ventricle fired in close relation to the cardiac cycle as revealed by constructing post-R-wave time histogram of their activity. Fibres with cardiac rhythmicity were all myelinated. The second group of the spontaneously active fibres had their receptive field in the left atrium. The activity of these fibres was slightly or not at all correlated with cardiac cycle. They were both myelinated and unmyelinated fibres.     

Neuropeptide Y-lmmunoreactive Nerve Fibres in the Pineal Gland of the Macaque (Macaca fascicularis)

The distribution of neuropeptide Y (NPY)- and the C-fianking peptide of NPY (CPON)-immunoreactive elements in the pineal gland of the macaque was investigated by means of immunohistochemistry. NPY- and CPON-immunoreactive nerve fibres were located in the precommissural nucleus, around the stria medullaris, and in the posterior commissure. NPY- and CPON-immunoreactive nerve fibres endowed with bulbous varicosities, were traced from the brain via the pineal stalk into the rostral part of the pineal gland. Furthermore, CPON-immunoreactive, and to a lesser extent NPY-immunoreactive nerve fibres, were distributed in the méninges, the choroid plexus and the vasculature related to the pineal organ. Nerve fibres located in the pineal capsule penetrated into the pineal parenchyma, where groups of individual fibres were found most often in an interlobular position. Occasionally, individual nerve fibres dispersed between the pinealocytes were observed. In contrast to the nerve fibres originating from the brain, those originating from the periphery were endowed with smaller immunoreactive nerve terminals. Another apparent difference was that the peripheral nerve fibres innervated only the caudal two-thirds of the gland, whereas the central fibres were found exclusively in the rostral part of the pineal organ. Rarely, positive neuronal-like cells were found in the pineal parenchyma. These results show the presence of a moderate number of NPY- and CPON-immunoreactive nerve fibres within the primate pineal organ and strongly indicate that the primate pineal gland is innervated by NPYergic nerve fibres originating from both a peripheral and a central source.     

Partial cytochrome c oxidase deficiency and cytoplasmic bodies in patients with zidovudine myopathy.

A histochemical study of cytochrome c oxidase (CCO) was performed in the muscles from eight patients with full-blown zidovudine myopathy. All patients had ragged-red fibres (total cumulative count: 160) and myofilamentous changes, that predominated in type 1 fibres and included diffuse or punch-out myofibrillar loss (75 affected fibres) and constant cytoplasmic body formation (106 affected fibres). Inflammatory infiltrates were present in four out of eight patients. A partial CCO deficiency (22-47% of fibres; both types 1 and 2 affected) was detected in all cases, and contrasted with the normal or increased succinate dehydrogenase activity observed in most fibres. Among CCO-deficient fibres, 71% were normal on trichrome, but all ragged-red fibres were CCO-negative. Myofilamentous changes were restricted to CCO-deficient fibres. The present study strongly supports the idea that mitochondrial toxicity is the specific mechanism of zidovudine myopathy.     

Further histochemical studies on masticatory muscles

This paper describes a histochemical and histographic analysis of the masticatory muscles obtained from 78 early autopsy samples from subjects from 4 days to 87 years old. Five groups of muscles have been stuied: the temporalis, the medial and lateral pterygoid, the superficial bundle of the masseter and the mylohyoideus. All adult muscles have consistently shown a markedly increased number oftype II fibres and a disparity in the size of the two main fibre types, the average diameter of type II fibres being about half that of type I fibres. Fibres of intermediate size and stain were observed with myofibrillar ATPase at pH 9.40. A negative relation between the percentage of type II fibres and intermediate fibres was found, but not between the percentage of type I fibres and of intermediate fibres. Another negative relation was found between the number and the size of type II fibres, again not present in type I nor in intermediate fibres. In children, from 6 days old, an increased number of type II fibres and a definite disparity in the size of the two main fibre types were found. Intermediate fibres were present on the 17th day. Up to the age of 13 years, their diameter was greater than that of type I fibres. The analysis of the distribution and size modifications of the various fibre types seems to indicate a progressive adaptation of the masticatory muscles. This adaptation of the fibres to the successive reactions and to the various movements of the masticatory system is then discussed.     

Immunohistochemical demonstration of APP (Avian Pancreatic Polypeptide)-immunoreactive nerve fibres around cerebral blood vessels

Nerve fibres containing immunoreactive avian pancreatic polypeptide (APP) were demonstrated in the wall of cerebral blood vessels from several species. Pial arteries of chicken, mouse, rat, guinea-pig, cat and dog had a dense supply of APP fibres while APP fibres were less numerous in rabbit, cow and monkey. The APP-immunoreactive fibres were more numerous in the rostral part of the circle of Willis than around more caudally located pial vessels. Immunoreactive fibres were also seen in the wall of pial vessels of the spinal cord, as shown in the cat. Extirpation of the superior cervical sympathetic ganglion was followed by a marked reduction in the number of APP-containing fibres on the ipsilateral side of the brain.     

Quantitative changes of sural nerves in various neurological diseases

Summary Quantitative histological studies were made on sural nerve biopsies from 123 patients with various neurological disorders. The myelinated fibre density, nuclear density, and the thickness of the perineurium were measured and compared with the average and standard deviation of control material in different age groups.Specimens from chronic polyneuritis and heredodegenerative neuropathy showed a reduction of myelinated fibres and an increase of nuclei, the decrease of large myelinated fibres being greater than that of small myelinated fibres.In acute polyneuritis the large and small myelinated fibres decreased equally in number. In the sensory type of SMON, small myelinated fibres decreased more than large myelinated fibres, while in the sensorimotor type of SMON, the change was the reverse. Nuclear population remained unchanged in these diseases.In spinocerebellar degeneration there was a close correlation between the decrease in myelinated fibres and the clinical findings such as sensory disturbance and diminished tendon reflexes, suggesting the presence of peripheral nerve involvement.Myelinated fibres were reduced in cases of neurological diseases hitherto considered to be free of pathological changes in sensory nerves, including motor neurone disease, myopathy, tumours or vascular diseases of the brain and spinal cord. In motor neurone disease and myopathy the large fibres were decreased more than small fibres, and nuclear population was increased. In tumours or vascular disease of the central nervous system, the large and small fibres were decreased equally in number, and the nuclear population was within normal range.     

强直性肌营养不良症的临床与肌肉病理学特点

目的探讨强直性肌营养不良症(DM)的临床及肌肉病理学的特点。方法对6例DM患者的临床资料进行回顾性分析。结果6例患者均呈慢性病程,以肌无力、肌强直和肌肉萎缩为主要表现,多伴有脱发、白内障、心脏传导阻滞等多系统损害。肌电图检查结果为肌源性损害,6例均可见肌强直电位发放。病理学检查见肌纤维核内移、核袋及核链现象,部分患者可见肌质块及肌纤维分布异常。结论DM是一种以肌无力和肌强直为主要表现的多系统损害的遗传性疾病;特征性病理改变为肌纤维核内移、核链以及肌质块、肌纤维分布异常。     

Postnatal differentiation and growth of skeletal muscle fibres in normal and undernourished rats. A histochemical and morphometric study.

The postnatal differentiation and growth patterns of the different histochemical muscle fibre types were studied at frequent age intervals in the extensor digitorum longus (EDL) muscle of normal rats and animals subjected to pre- and postnatal protein-calorie undernutrition. Three stepwise changes were seen in the fibre type composition of the EDL muscle during maturation. In newborn normal rats 2 histochemically and morphometrically distinct fibre populations occurred: small foetal type (type F) fibres or myotubes (about 90%), with the staining characteristics of the so-called type 2C fibres, and larger type 1 fibres (10%). At 5 days of age the percentage of type F fibres had dropped to 50 simultaneously with the emergence of a new population (40%) of type 2B fibres, intermediate in cross-sectional area between the remaining type F fibres and type 1 fibres. Between 15 and 20 days the small type F fibres practically disappeared with the emergence of a corresponding percentage (40%) of type 2A fibres, smaller than both type 1 and type 2B fibres; Between 20 and 60 days the percentage of type 1 rose from 10 to almost 30, type 2B fibres correspondingly diminishing in number but growing at a faster rate than either type 1 or type 2A fibres. In the undernourished rats the histochemical differentiation was retarded at birth, all fibres or myotubes being of the foetal type; However, large type 1 and type 2B fibres were seen at the age of 5 days and the histochemical maturation proceeded almost normally at later stages. On the other hand, at all ages there was a proportional reduction in the cross-sectional area of all fibre types, amounting to about 50% at 180 dyas, and not fully restituted by nutritional rehabilitation. These observations suggest that type F (type 2C) fibres are the undifferentiated precursors of all mature muscle fibres, their stepwise histochemical transformation raising the question of maturational differences in the different types of motoneurones.     

Perivascular substance P: occurrence and distribution in mammalian pial vessels

Nerve fibres containing immunoreactive substance P (SP) were demonstrated in the wall of cerebral blood vessels of several mammalian species. Pial arteries of cat and guinea-pig were richly supplied with SP nerve fibres, while those of rat, rabbit, pig, and man had a moderate number. SP fibres were more numerous in pial vessels belonging to the rostral parts of the circle of Willis as compared to more caudally located blood vessels. In cat and guinea-pig, blood vessels in the choroid plexus were surrounded by few SP nerve fibres; also spinal cord blood vessels of cat contained few such fibres.     

Contrasting histochemical features of various mitochondrial syndromes

A comparative histochemical analysis of the prevalence and cytochrome oxidase staining characteristics of ragged-red fibres in limb skeletal muscles was performed in 19 patients spanning four distinct mitochondrial syndromes: chronic progressive external ophthalmoplegia; myoclonus epilepsy with ragged-red fibres; mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes; and pure limb myopathy. The percentage occurrence of non-ragged red but cytochrome oxidase negative fibres was additionally noted. Ragged-red fibres and cytochrome oxidase-negative fibres were generally more prevalent in the chronic progressive external ophthalmoplegia syndrome than in myoclonus epilepsy ragged-red fibres syndrome or mitochondrial myopathy encephalopathy lactic acidosis and stroke-like episodes syndrome. Isolated cytochrome oxidase-negative fibres were a common finding in each phenotypic syndrome except pure limb myopathy and could involve any of the major fibre types non-specifically. Ragged-red fibres were devoid of cytochrome oxidase activity in chronic progressive external ophthalmoplegia, but commonly displayed activity in the other three syndromes providing a clue to syndromal differentiation on a histochemical basis.     

Histochemical enzyme profiles of fibres in human masseter muscles with special regard to fibres with intermediate myofibrillar ATPase reaction

Histochemical staining methods were applied to biopsy material from the masseter muscles of 17 subjects who were being operated upon for mandibular prognathism. Comparisons were made with biopsy specimens from 8 biceps brachii muscles.In biceps brachii only fibres of type I (weakly stained) and fibres of type II (strongly stained) were demonstrated with the myofibrillar ATPase reaction at pH 9.4, whereas in the masseter, fibres with an intermediate intensity of staining were distinguished along with type I and type II fibres in 36 of 38 specimens. Like type I fibres these fibres exhibited a strong or moderate NADH₂ tetrazolium reductase reaction, a strong ATPase reaction after acid preincubation, and a weak ATPase reaction after alkali preincubation; however, like type II fibres they showed a strong phosphorylase reaction.Further studies are required to determine whether this pattern is part of the normal anatomy or reflects alterations in muscle function.     

Anti-vimentin staining in muscle pathology

The intermediate filaments of immature muscle fibres contain desmin and vimentin; vimentin is lacking in mature fibres. Regenerating fibres react with anti-vimentin antibodies and more intensely for desmin than mature fibres. The aim of the present study was to evaluate anti-vimentin staining for muscle pathology. Anti-vimentin-reactive fibres were found in 40 of 89 biopsies assessed. Fifteen patients with progressive destructive myopathy, infantile spinal muscular atrophy, clinically suspected Leigh's disease or unclassifiable congenital myopathy had between 1% and 95% vimentin-positive fibres. Less than 1% positive fibres were found in 25 patients with neuropathy with secondary myopathy or chronic myopathic conditions. Vimentin-positive fibres were lacking in 20 normal biopsies, in eight biopsies with neuropathic and in 21 biopsies with mild or non-destructive myopathic changes. We conclude that staining with anti-vimentin antibodies is a useful indicator for muscle fibre regeneration; it may help establish the diagnosis in infantile spinal muscular atrophy when the histopathology is non-characteristic. The high incidence of reactive fibres in some congenital or early-onset disorders may indicate developmental arrest.     

Distribution of different fibre types in human skeletal muscles: A statistical and computational model for the study of fibre type grouping and early diagnosis of skeletal muscle fibre denervation and reinnervation

To define fibre type grouping in terms of random and non-random arrangements of the two fibre types, type 1 (ST) and type 2 (FT), we adopted the measure of counting the number of “enclosed fibres”;. The statistical properties of the number of enclosed fibres, and the number and size of groups of enclosed fibres were studied in computer-simulated muscle cross-sections, using a model based upon hexagonal-shaped fibres. The effects on the results of differences in the sizes of the muscle fibres were considered. The applicability of the model, and the derived results and methods of analysis were tested on 10 samples from a cross-section of a whole human muscle. The results show that the model can be applied to various shapes and sizes of muscle samples and various sizes of muscle fibres. The number of enclosed fibres within a muscle sample is the best of the three measures of non-randomness considered. A test is also described for assessing whether or not the observed number of enclosed fibres is random at a given significance level.     

Size and distribution of histochemical fibre types in masseter muscle of adults with different states of occlusion

Histochemical staining methods were applied to biopsy specimens from the masseter muscles of 17 healthy subjects with mandibular prognathism and 4 subjects with benign parotid lesions. Fibre sizes and percentage fibre distributions were assessed in transverse sections stained for myofibrillar ATPase at pH 9.4. Size or percentage distribution of different fibre types was not significantly correlated to the state of occlusion. In subjects with unilateral chewing only, the frequency of Type I fibres (lightly stained) was higher (P < 0.01) and the frequency of intermediate fibres (moderately stained) lower on the chewing side than on the non-chewing side (P < 0.05). Type I fibres were invariably larger than Type II (strongly stained) fibres—mean value 33.2 μm versus 17.9 μm. There was no significant relationship between the sizes of Type I and Type II, but there was between Type I and intermediate fibres (P < 0.05). Intermediate fibres were generally intermediate in size to Type I and Type II, mean value 23.8 μm. The range of percentage distribution of the 3 types of fibres was wide. Average values were Type I 29%, type II 57% and intermediate fibres 14%. There was an indication that fibres from different depths of the muscle differ in size and in percentage distribution. The size of Type I and its percentage distribution were significantly negatively correlated (P < 0.01). The percentages of Type II and intermediate fibres were negatively correlated (P < 0.001) but not those of Type I and intermediate fibres. It is suggested that ATPase-intermediate fibres may result from transformation of Type II fibres.     

An immunohistochemical study of neuropeptides and neuron-specific proteins present in the small intestine of the black-capped capuchin (Cebus appela)

Abstract Antisera against neuron specific enolase (NSE), calbindin and the neuropeptides substance P (SP), vasoactive intestinal peptide (VIP), neuropeptide Y (NPY), enkephalin (ENK) and somntostatin (SOM) were used to demonstrate the presence of nerve fibres and cell bodies in the small intestine of the black-capped capuchin, Cebus appela. NSE-immunoreactive (IR) nerve fibres werefoundin all layers of the intestinal wall, except the longitudinal muscle, and immuno-reactive nerve cell bodies were found in both myenteric and submucous plexuses. The submucous plexus was composed of external and internal ganglionated plexuses. Endocrine cells in the epithelium were reactive for NSE. In ganglia of the myenteric plexus, SP-, VIP-, ENK-, SOM-, NPY- and calbindin-IR varicose and non-varicose fibres were found around reactive and unreactive cell bodies. Calbindin, ENK-, SP-, SOM- and VIP-IR, but not NPY-IR, nerve cell bodies were observed. The primary and secondary plexuses contained fibres of each type examined. The tertiary plexus was rich in SP-IR fibres, although ENK-, NPY-, SOM- and VIP-IR fibres were also observed. The deep muscular plexus had mainly ENK- and SP-IR fibres and few VIP-IR fibres, while in the remainder of the circular muscle VIP-IR fibres predominated. There were few SP-IR and no ENK-IR fibres in this layer. The two ganglionated plexuses of the submucosa contained ENK-, NPY-, SOM-, SP- and VIP-IR fibres, but calbindin-IR fibres were not found. SP- and VIP-IR cell bodies were found in both plexuses. Blood vessels had SP-, VIP- and NPY-IR fibres around them. SP-, VIP- and a few SOM-IR pbres innervated the mucosa, while endocrine cells were found with SP-, SOM- and NPY-IR. The present study demonstrated that the distribution of the neuropeptides SP- and VIP-IR is similar in the small intestine of the black-capped capuchin to that in the dog, guinea pig, human and rat. SP- and VIP-IR possibly mark neurons of the same function in each species. Distributions of ENK-, NPY-, SOM- and calbindin-IR differ substantially between species.