A novel photopigment candidate in membranes of cultured chick pineal cells

The photopigment of avian pineal which mediates light sensitivity was sought via its chromophore. Chick pineal cells in primary cultures were incubated overnight in the dark with [3H]retinol. Reduction of Schiff's bases with cyanoborohydride prior to SDS-PAGE revealed radioactivity bound to a 30 kDa component in pinealocyte membranes. All-trans-retinal, but not retinol or retinoic acid, incubated with pinealocyte homogenates prior to reduction, resulted in a loss of radioactivity from the 30 kDa region of the gel. The radioactivity was also displaced by NH2OH in the dark. Incubation of cultured cells or homogenates with retinoyl fluoride, an acylating agent specific for the retinal binding site of opsins, also displaced radioactivity from the protein. Furthermore, retinoyl fluoride, added to chick pineal cells in culture, blocked the suppressive effect of light on melatonin output by these cells. Taken together these results raise the possibility that the 30 kDa protein mediates photosensitivity in the chick pineal.     

Sarcoglycanopathies: a multiplex molecular analysis for the most common mutations.

Sarcoglycanopathies (SGpathies) are highly frequent among severely affected limb-girdle muscular dystrophy patients. On the basis of the findings of 5 common mutations in the 4 sarcoglycan (SG) genes in the Brazilian population, we standardized a multiplex polymerase chain reaction-single-strand conformation polymorphism methodology for their concomitant analysis in DNA samples. The test was able to confirm the diagnosis in about 63% of new patients with a suspected SGpathy and was particularly important in patients in advanced stages of the disease, when obtaining a muscle biopsy for analysis may be very difficult. As common mutations have been described in several countries, this multiplex analysis could be useful for the diagnosis of SGpathies if established according to the most prevalent mutations in each population. Besides, even though the disorder studied is rare, the technique could be broadly applicable to other genes and disorders.     

Screening of male patients with autosomal recessive Duchenne dystrophy through dystrophin and DNA studies

Previously we estimated that about 2.5-4% of isolated male patients diagnosed as Duchenne dystrophy (DMD) may have the autosomal recessive form (AR-DMD). Such cases can be distinguished from X-linked DMD through the analysis of dystrophin. Fifty DMD patients from 47 families were investigated for dystrophin and DNA deletions. Based on our results, we estimate that the frequency of AR-DMD may be about 8-12% among male patients diagnosed as DMD in whom X-linked inheritance could not be confirmed through pedigree data, serum enzymes in female relatives or DNA studies. Such an estimate must be confirmed in a larger sample; however, it shows the importance of assessing dystrophin in all patients diagnosed as DMD in whom X-linked inheritance cannot be proved, since the distinction between these 2 forms has implications for genetic counseling.     

The effect of calpain 3 deficiency on the pattern of muscle degeneration in the earliest stages of LGMD2A

Limb girdle muscular dystrophy type 2A (LGMD2A) is caused by mutations in the calpain 3 gene. In a large family affected by LGMD2A with four severely affected members, three additional asymptomatic relatives had very high serum creatine kinase concentrations. All were homozygous for the R110X mutation and showed a total absence of calpain 3 in the muscle. Histological analysis of muscle in these three rare preclinical cases showed a consistent but unusual pattern, with isolated fascicles of degenerating fibres in an almost normal muscle. This pattern was also seen in one patient with early stage LGMD2A who had a P82L missense mutation and a partial deficiency of calpain 3 in the muscle, but was not seen in early stage patients affected by other forms of LGMD. These findings suggest that a peculiar pattern of focal degeneration occurs in calpainopathy, independently of the type of mutation or the amount of calpain 3 in the muscle.     

How the magnitude of clinical severity and recurrence risk affects reproductive decisions in adult males with different forms of progressive muscular dystrophy.

The reproductive history of 177 male patients affected with Becker (BMD) (n=69), limb-girdle (LGMD) (n=54), and facioscapulohumeral (FSHMD) (n=54) muscular dystrophy (MD) was analysed according to severity of the disease (BMD>LGMD>FSHMD) and magnitude of recurrence risk (RR) (high for FSHMD, intermediate for BMD, and low for LGMD). Additionally, 62 male patients were interviewed on psychosocial issues, in order to disentangle the factors influencing reproductive decisions among patients affected with MD. Among male adults, significantly more FSHMD than LGMD or BMD patients were married and had children. Age specific reproductive outcome was 0.31-0.32 for BMD, 0.51-0.62 for LGMD, and 0.58-1.02 for FSHMD, reflecting the influence of the disease's severity. High RRs did not significantly diminish reproduction after genetic counselling or correlate with less prospective desire for children. Instead, early onset, severity of the disease, and past reproductive history were found to diminish reproductive outcome after genetic counselling, and prospective family planning was also found to be influenced by past reproductive history as well as by emotional/sexual dysfunction with the opposite sex.     

Duchenne muscular dystrophy in a girl with a 45,X/46,XX/47,XXX chromosome constitution

We report on a 4-year-old girl with Duchenne muscular dystrophy (DMD). One of her sisters had grossly elevated serum creatine-kinase and pyruvate-kinase levels, and one of her maternal great uncles was presumptively affected by DMD. Cytogenetic analysis showed a 45,X/46,XX/47,XXX chromosome constitution. The maternally inherited DMD gene is presumed to be present on the single X of the 45,X cell line.     

Estimate of the proportion of Duchenne muscular dystrophy with autosomal recessive inheritance

The aim of the present report was to estimate the proportion of autosomal recessive (AR) inheritance among families with affected males diagnosed as Duchenne muscular dystrophy (DMD) in which X-linked inheritance could not be confirmed. A total of 470 families was studied: 20 with at least one affected girl with "Duchenne-like" phenotype and 450 with only affected boys. Based on the number of families with at least one affected girl and the number of patients per sibship among these pedigrees, the proportion of families with DMD inherited as an AR trait was estimated at 6.8%. It is also estimated that 2.5-4% of male isolated patients diagnosed as DMD may have the AR form, which could be one possible explanation for the inconsistent results between clinical diagnosis and dystrophin assessment in one case recently reported.     

Changes in lymphoid populations of ageing CBA and NZB mice

Changes in subpopulations of lymphoid cells of normal (CBA) and autoimmune (NZB) mice were studied as a function of age, by observing migration patterns of ⁵¹Cr labelled lymph node, spleen and thymus cells from donors aged 8 days to 12 months. The method permits analysis of the proportions and numbers of recirculating and non-recirculating lymphocytes in lymphoid compartments. Changes in the lymphoid populations of CBA mice were found, which could be attributed to the normal processes of maturation and senescence. In NZB mice relative and absolute decreases in the recirculating cell content of lymph node and spleen were observed which coincided with the time of development of autoimmunity. The significance of these results, in relation to altered immunocompetence with age, is discussed.     

Serum CK-MB activity in progressive muscular dystrophy: Is it of nosologic value?

Serum creatine-kinase (CK) isoenzyme MB was measured in 53 patients affected by different types of myopathies (20 with Duchenne muscular dystrophy (DMD), eight with the Becker form (BMD), ten with the limb-girdle form (LGMD), six with the facioscapulohumeral form (FSH), and nine affected by polymyositis and in 21 normal control subjects). The aim of this study was to compare each group with the control individuals and to assess the nosologic value of CK-MB activity among some clinically similar dystrophies, which may have an important application for genetic counseling. A statistically significant increased CK-MB activity was found only in the Duchenne and Becker patients when compared with control persons (p < 0.05). When the different groups of patients were compared among themselves, no significant difference was found between DMD and BMD or LGMD and polymyositis. However, a significant difference was found between BMD and LGMD. Based on these data, it is possible, through discriminant analysis, to estimate the relative biochemical probability of an isolated male patient belonging to either group.