Capillaries of human overacting extraocular muscles.

The capillaries of overacting inferior oblique muscles from children with strabismus and of dog inferior oblique muscles were ultrastructurally described. Biopsy material was used in all instances. The mean diameter of the capillary lumen was 2.03 microns for the human inferior oblique and 2.76 microns for the dog inferior oblique. Quantitative estimates of capillary basement membrane width were obtained by two different methods of measurement. The capillaries of human and dog inferior oblique muscles were compared with capillaries of human gastrocnemius muscle and of dog quadriceps muscle. The data were statistically evaluated. It was found that the mean basement membrane width of capillaries of overacting inferior oblique muscles is quite similar to that of the dog normal inferior oblique muscles, showing 2,049 A in overacting muscles and 1,976 A in normal muscles. With both methods of measurement, the mean basement membrane width of inferior oblique muscles appeared thicker than the mean basement membrane of capillaries of the leg muscles in man and in dog as well. It is suggested that the thickening of the capillary basement membrane of inferior oblique muscles represents a regional characteristic. Marked variation in the thickness of the basement membrane was encountered in all muscles.

Abnormalities of intramuscular nerves in old mice: an ultrastructural study.

Intramuscular branches of tibial nerves of 5- and 27-month-old mice were compared. Seventeen intramuscular nerve fascicles were studied in each group: 174 myelinated axons were evaluated in the young mice, and 136 in the aged mice. The old mice showed significant decreases in numbers of myelinated axons per nerve, and these had significant decreases in concentrations of mitochondria. Interaxonal collagen and numbers of collagen fibrils were increased, as was the concentration of unmyelinated axons. Myelinated axons of old mice demonstrated myelin disorganization, myelin nodules, degeneration of axoplasm and Schwann cells.

Evidence of Schwann cell degeneration in the aging mouse motor end-plate region.

An ultrastructural evaluation was made of the changes encountered in the motor endplates of the gastrocnemius muscle of old mice in comparison with young-adult mice. In old, 27-month-old mice, a great variety of changes were recorded. The main abnormalities occurred in the axon terminals, the myoneural junctional folds, and the endomysial space. Loss of synaptic vesicles and mitochondria and vacuolization of axon terminals were common. Shrinkage and degenerative changes of axon terminals were noticed. The end-plate abnormalities were closely associated with an increased amount of collagen tissue, degenerated Schwann cells, and cell debris. Degenerated Schwann cells were not encountered in young-adult mice. In the old group, endplates of normal appearance occurred in the proportion of 40%. The young group had normally structured end-plates in the proportion of 85%. The lesions described are not specific for the aging process.

Cerebro-oculo-facio-skeletal syndrome: further delineation.

We report on a newborn infant with cerebro-oculo-facio-skeletal (COFS) syndrome. Congenital muscular dystrophy-like changes were present in this patient. It is debated whether the clinical spectrum of the COFS phenotype should be expanded to include congenital muscular dystrophy:

Muscle involvement in Walker-Warburg syndrome. Clinicopathologic features of four cases.

Walker-Warburg syndrome is a lethal autosomal recessive disorder characterized by anomalies of the central nervous system and the eye. Recently, elevation of muscle enzymes and congenital muscular dystrophy have been found to contribute to the diagnosis of this syndrome. The authors studied two pairs of siblings with Walker-Warburg syndrome, offspring of consanguineous parents from two unrelated families. The patients had hydrocephalus, congenital glaucoma, elevated muscle enzymes, and hypotonicity. The histologic and ultrastructural muscular changes were consistent with congenital muscular dystrophy.

Myotonia dystrophica with heart involvement: an electron microscopic study of skeletal, cardiac, and smooth muscle.

The electron microscopic features of the striated skeletal muscle, the striated cardiac muscle, and the smooth muscle from a woman who had been suffering for many years from myotonia dystrophica with cardiac involvement are described. The skeletal muscle was studied at two different stages of the disease. In the first material the main changes consisted of centrally situated nuclei, disorganisation of the sarcomeres, and focal disruption of the Z-line. The satellite cells were well represented. Three years later atrophy and degenerative, necrotic changes of the skeletal muscle were evident. The satellite cells were absent. Few changes were seen in the striated cardiac muscle. These consisted of slight interstitial fibrosis and large accumulations of mitochondria with intramitochondrial dense granules. The smooth muscle cells of the oesophagus showed disorientated filaments and mild degenerative changes. It is concluded that the skeletal muscle was more severely affected than the other types of muscle.

Evaluation of muscle capillary basement membrane in inflammatory myopathy. A morphometric ultrastructural study.

The capillary basement membranes from 16 skeletal muscle biopsies from patients with a clinical and histological diagnosis of inflammatory myopathy and from six controls were analysed ultrastructurally and morphometrically. Resin sections from 244 endomysial capillaries were examined by light microscope, and the results were correlated with findings seen in electron micrographs of these capillaries. The ultrastructural morphometric measurements and the statistical analysis showed that the capillary basement membrane was thick and multilaminated in 87% specimens affected by inflammatory myopathy. No thick or multilaminated basement membrane was observed in controls. In inflammatory myopathy the endomysial space next to the capillaries contained an increased amount of collagen fibrils and showed signs of a chronic reparative process. It is suggested that the thick multilaminated basement membrane in inflammatory myopathy represents an advanced stage of vascular regeneration.

Primary and secondary overacting inferior oblique muscles: an ultrastructural study.

Biopsy material from primary and secondary overacting inferior oblique muscles were examined by light and electron microscopy. Most muscle fibres were in different stages of atrophy. A high variation of alterations was encountered in all muscles. The most striking abnormalities were huge accumulations of mitochondria and muscle vacuolisation related mainly to the enlargement of the tubules of sarcoplasmic reticulum. The mitochondrial aggregates and vacuolisation occupied more muscle surface in the inferior muscles of primary overaction than those of secondary overaction.

The susceptibility of renal arterial forks in rabbits to dietary-induced lipid deposition.

The major forks of the renal arteries from 21 rabbits fed a cholesterol-supplemented diet for periods of 1-90 d were examined electron-microscopically to compare the changes in the stem of the renal arteries with those at the first main fork. Lipid accumulated preferentially in the intimal pads or cushions at the fork. Matrix vesicles diminished in number and appeared to be transformed into enlarged membrane-bound vacuoles with electron-translucent contents. Foam cells were observed particularly beneath the endothelium. The lipid in endothelial and smooth muscle cells differed from that in the foam cells, indicating the likelihood of a different metabolic response. Interstitial lipid resembled an infiltration of the matrix with separation of the mural constituents but was not associated with the increased cellular degeneration, the progressive accumulation of matrix vesicles or the augmentation of the dystrophic basement membrane changes prominent in spontaneous atherosclerosis. In the arterial stems of 2 rabbits fed cholesterol for 62 and 90 d respectively, interstitial lipid deposition occurred without intimal proliferation.

Collagen fibril abnormalities in the extraocular muscles in Ehlers-Danlos syndrome.

The dermal collagen fibrils and the fibrils of the extraocular muscles and the conjunctivas of both eyes of a child afflicted with Ehlers-Danlos syndrome (EDS) were studied ultrastructurally. The results were evaluated statistically. Biopsy material was used in all instances. The collagen fibrils from all involved tissues showed a high percentage of size variation. Abnormalities of shape were noted. In the reticular dermis, 48% of fibrils were of normal diameter, 23% were enlarged, and 29% were thinner than normal. In the extraocular muscles, 77% were of normal size, 14.5% were larger, and 8.5% were smaller. In the conjunctivas, 73% of fibrils were normal-sized, 22% were enlarged, and 5% were of small diameter. No small-sized fibrils were encountered in control extraocular muscles.

Ultrastructure of human dermal blood vessels with special reference to the endothelial filaments.

The ultrastructure of endothelial cytoplasmic filaments of small blood vessels from the human dermis has been described. The material consisted of biopsies from normal abdominal and thoracic skin and also from the skin of patients with urticaria pigmentosa. Most vessels were surrounded by multiple layers of basal lamina and corresponded to the small venules of the subpapillary dermis. The wall of many vessels was composed by endothelial cells with clear cytoplasm which was rich in filaments and by endothelial cells with a dense cytoplasm which was poor in filaments. Some vessels had walls composed of clear endothelial cells only. The filaments varied in diameter between 80-120 A. Curling, recoiling and whorling of cytoplasmic filaments were obvious in endothelial cells of contracted vessels. Bulging of endothelial nuclei and nuclear indentations were seen in the skin lesion of urticaria pigmentosa. The possibility that the clear endothelial cells which are rich in filaments may be more actively involved in contraction than the dense cells, is discussed.

Ultrastructure of the immediate, histamine-mediated microvascular response in human skin with urticaria pigmentosa.

The immediate microvascular response in the skin of adults with urticaria pigmentosa after activation of mast cells was examined with the electron microscope. Mast cell degranulation was activated by gently rubbing the cutaneous lesion, and biopsy material was removed 5 to 10 min following stimulation. Aspects of mast cell degranulation were found in all the samples. Several indications of the effects produced by histamine release upon permeability of the small upper dermal venules were evident: (1) Scattered endothelial contraction, which resulted in alternation of contracted and dilated portions of the endothelial wall. Deep nuclear indentations in the contracted endothelial cells occurred in a proportion of 53%. (2) Marked dilation and congestion of some venules. (3) Randomly distributed interendothelial gaps, with platelets or red blood cells traversing the gap. The open junctions of small diameter were numerous, whereas the large gaps were numerically few. (3) The presence of a dense material consistent with plasma protein beneath and external to the vascular basement membrane. Vessels showing aspects similar to those occurring after mild thermal injury were noticed. The possibility exists that several mediators and mechanisms superimpose during the early histamine-mediated phase of the vascular response in urticaria pigmentosa following activation of mast cells.

Patterns of regeneration in vessels of human diseased muscle and skin. An ultrastructural study.

Regenerating vessels from 36 muscle biopsies and 12 skin biopsies pertaining to patients with the clinical and histological diagnosis of dermatomyositis-polymyositis and other inflammatory myopathies were described ultrastructurally. The following characteristics of vascular regeneration were encountered: a) alternation of thin and thick endothelial cells, b) superimposed segments of endothelial cytoplasm with formation of twisted intercellular junctions, c) long and complex intraluminal endothelial projections, d) discontinuous and porous perivascular basement lamina or multilaminated basement lamina. Some vessels featured only two or three of the mentioned characteristics. Endothelial fenestrations were occasionally encountered in the skin capillaries and were an exception in the muscle capillaries. In the skin there were aspects suggesting that intercalation of perivascular cells in the regenerating endothelial wall may occur. Most capillaries were in the final stage of regeneration.

Massive fibrosis of extraocular muscles related to intraocular tumor.

A resin histological and ultrastructural study of 9 fibrotic extraocular muscles from 2 patients who underwent enucleation because of advanced intraocular malignant melanoma is reported. Total fibrosis of the extraocular muscles was evident in one case and extensive fibrosis in the other case. The patients did not suffer from congenital fibrosis syndrome. Ultrastructurally, the muscle tissue was replaced by collagen fibrils showing great variability of caliber.

Comparative ultrastructural study of generalized and localized granuloma annulare.

The dermal changes in four cases of generalized granuloma annulare (GGA) and in four of localized granuloma annulare (LGA) were studied ultrastructurally, and the findings in the two groups were compared. The basic alterations were similar in both types, and showed varied stages of development. The cellular infiltrate was composed mostly of histiocytes. Cell debris was found in all lesions. The degenerative changes affected the collagen fibers, the elastic fibers, and the cellular infiltrate. Of special interest are the following findings in GGA: First, masses of intercellular fibrin material were seen only in the lesions of GGA. Second, thick and multilayered basal lamina around capillaries was apparently more common in the generalized form. These changes may suggest that a more pronounced immune reaction is responsible for the development of the generalized form of the disease.

Ultrastructural observations on the capillaries of human thyroid tumours.

Ultrastructure of the capillaries of malignant and benign thyroid tumours has been examined. The material consisted of biopsies from six cases of thyroid papillary carcinoma, one case of follicular (foetal type) adenoma and six cases of nodular adenomatous goitre. In the group of nodular adenomatous goitre and in the follicular adenoma, the capillary wall was made up of fenestrated endothelium similar to that of capillaries of normal human thyroid. The fenestrae occupied a large area of the endothelial wall. Micro- and macropinocytotic vesicles were frequent in the endothelial cytoplasm. In the thyroid carcinomas the papillary structures always contained numerous capillaries with fenestrated endothelium. The microfollicular area and the solid tumoral areas of the papillary carcinoma showed occasional capillaries with fenestrated endothelium, but many capillaries were lined with continuous endothelium. The capillaries in all the specimens were surrounded externally by a continuous basement membrane which was frequently bilaminate or multilaminate. This study indicates that capillaries with fenestrated endothelium are characteristic of thyroid tumours which arise from follicular cells.

Connective tissue of the orbital cavity in retinal detachment: an ultrastructural study.

The connective tissue from Tenon's capsule of 7 patients who underwent surgery for retinal detachment was studied ultrastructurally. Five patients were 58-70 years old, and 2 were young adults. The Tenon capsules of 6 children and of 2 aged patients without retinal problems were used as controls. In young controls the Tenon capsule was composed mainly of round, smooth collagen fibrils and a few elastic fibers. The collagen fibrils varied in size from 70 to 110 nm. In the aged patients with retinal detachment, the collagen fibrils showed marked variation of size and also abnormalities of shape in 4 out of 5 cases. The diameter of collagen fibrils varied from 32 to 160 nm, and the elastic fibers were fewer as compared with controls. The possibility arises that age-related structural changes of the orbital connective tissue could predispose to retinal detachment.