Electrophysiological and histological examinations showed significant overlapping of several pathogenic components of neuromuscular involvement in critically ill patients, namely decreased muscle excitability, myopathy, axonal motor neuropathy and sensory neuropathy. The characterisation of the electrophysiological components of a complex polyneuromyopathy is preferred to the strict categorisation of abnormalities into critical illness myopathy and polyneuropathy.

Three monospecific monoclonal antibodies (BA16, BA17 and A53-B/A2) recognizing different epitopes of the human keratin 19 were used to determine tissue distribution of this 40 kDa keratin polypeptide. Immunohistochemical methods revealed four different staining patterns among normal human epithelial tissues: firstly, complete negativity of the epidermis, sebaceous glands, hepatocytes and other tissues; secondly, homogeneous positivity as seen for example in the gall bladder and urinary bladder epithelium, endometrium and many other epithelia; thirdly, a mosaic of positive and negative cells among mammary gland luminal cells, prostate epithelia and some other epithelia and fourthly, a more complex heterogeneous pattern found in non-keratinizing squamous epithelia and hair follicles with generally the basal layer being the most strongly or sometimes exclusively stained. The pattern seen in non-keratinizing squamous epithelia varied considerably according to the fixation method and the antibody used as well as among different donors and in different areas of the same organ. The other three staining patterns were on the other hand nearly identical with all three antibodies on both frozen sections and sections of methacarn-fixed paraffin-embedded tissues. Our results provide evidence for differential expression of the human keratin 19 at the single cell level, an observation which could be exploited in the study of epithelial differentiation and pathology.

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Human neurodegenerative and neuromuscular disorders are associated with a class of gene mutations represented by expansion of trinucleotide repeats. DNA testing is important for the diagnosis of these diseases because clinical discrimination is complicated by their late onset and frequently overlapping symptomatology. However, detection of pathologic alleles expanded up to several thousand trinucleotides poses a challenge for the introduction of rapid, fully automatic, and simple DNA diagnostic procedures. Here we propose a simple two-step polymerase chain reaction (PCR) protocol for rapid molecular diagnostics of myotonic dystrophy, Huntington's disease, and possibly also other triplet expansion diseases. Standard PCR amplification with target repeat flanking primers is used for the detection of alleles of up to 100 repeats; next, triplet-primed PCR is applied for detection of larger expansions. Automated capillary electrophoresis of amplicons allows rapid discrimination between normal, premutated and expanded (CTG/CAG)(n) alleles. Using the suggested protocol, the expanded allele was successfully detected in all test DNA samples with known genotypes. Our experience demonstrates that the suggested two-step PCR protocol provides high sensitivity, specificity, and reproducibility; is significantly less time-consuming; is easier to perform; and provides a better basis for automation than previous methods requiring Southern analysis. Therefore, it can be used for confirmation of uncertain clinical diagnoses, for prenatal testing in at-risk families, and, generally in research on these diseases.

Clinical, histopathologic, immunohistochemical, and genetic analyses of 2 osteoclastic giant cell tumors of the pancreas are presented. The neoplasms were composed of osteoclastic giant cells and pleomorphic cells (PCs). The tissue-specific markers gave evidence of mesenchymal nature of the osteoclastic giant cells, as well as other components of the tumor, and lacked any signs of epithelial differentiation in both patients. The nonepithelial nature of both components in the osteoclastic giant cell tumors presented may be associated with a better prognosis, which corresponds to the previous reports of similar neoplasms. A positive immunoreactivity to neuron-specific enolase was recorded in patient 2. The presence of CD68 in osteoclastic giant cells proved their histiocytic nature. Both components of the tumors showed a negative immunoreactivity to desmin and only a scattered reactivity to smooth muscle cell actin, typical markers of myofibroblastic differentiation. Mutation analysis of the tumor revealed the wild state of both p53 and K-ras oncogenes in both patients. A positive immunoreactivity for p53 in PCs of both osteoclastic giant cell tumors was recorded, whereas osteoclastic giant cells did not express this protein. The expression of p21 was recorded in osteoclastic giant cells in patient 1. The absence of Ki-67 in the osteoclastic giant cells and its expression in PCs gave evidence of a different proliferation rate of both cell populations. Different tissue-specific markers, a different proliferation rate, and a different state of oncogene activation in the osteoclastic giant cell tumors contribute to the idea that the tumor derives from a pluripotent cell that may differentiate into an array of phenotypes.

Muscle samples of the m. longissimus dorsi and m. biceps brachii from 6 splaylegged newbom piglets (12-48 hours post partum) were compared with similar muscles of the control animals of the same age. In most muscle fibres the sarcolemma was only partially filled with myofibrils, the rest-the exttamyofibrillar space (EMS) showed metachromatic staining with toluidin blue.in the aemithln sections. In the EMS we found glycogen particles showing positive Thi&y reaction, they were arranged in rosettes. This reaction and amylase digestion have shown that, in addition to glycogen, the EMS also contains ribosomes and polysomes which are usually located in the subsarcolemmatic areas. Polysomes were also found in the close proximity of the fine granular fibrous material inside the glycogen masses. They are probably bundles of maturated actin fibres. Glycogen is highly soldble in the aldehyde fixatives. Myofibrils were changed only exceptionally. The only variation was the finding of streaming Z lines. A decrease in number of myofibrils and alteration in their arrangement were observed in the proximity of the alteredZlines. These changes, however, were also recorded in control animals. No changes were found in the nuclear membrane of the karyoplasm or organelles suggestive of the splayleg syndrome. Myofibrillar hypoplasia, muscle fibre dwelopment, neuromuscular unit. Although the splayleg syndrome of newborn piglets has recently been subject of extensive histological, biochemical and ultrastrUctural studies, its etiopathogenesis remains unclear. This also reflects in various• names used in connection with the disease: myofibrillar hypoplasia, myofibriliar degeneration, myofibrillar retardaticn. Ultrastructural studies have described some positive findings that could be characteristic of the splay1eg syndrome.• The findings involve above all, changes in the nucleus and nuclear envelope (Zelena et al. .1978) and myofibrillar changes (Bergmann 1976; Zelena and Jirmanova 1979). By compa~ison of ultrastructural findings in muscles of splaylegged and healthy piglets we aimed at assessing the diagnostic significance of the changes reported. * This investigation has received financial support from W. H. O.

Three cases of nutritional myodegeneration caused by selenium deficiency in adult horses are described. Difficulty in eating and drinking was a common clinical sign in all horses. Blood biochemistry revealed a marked elevation of muscle enzymes and low glutathione peroxidase activity or low selenium concentration in whole blood in all cases. The treatment with sodium selenite and vitamin E was instituted in all horses. Two of them were euthanized because of continuing muscle injuries, one patient was cured. The post-mortem examination of euthanized horses revealed pale muscles that were distributed with bilateral symmetry on hind and thoracic limbs, diaphragm, tongue, masticatory and intercostal muscles and the myocardium. Histopathology revealed the areas of degeneration and necrosis. Large groups of regenerating fibres and pronounced lymphoplasmocytic reaction among the groups of intact fibres were also present. The clinical outcome of the disease is probably influenced by timely diagnosis and treatment.