Gallium-67 scintigraphy in macrophagic myofasciitis

OBJECTIVE

To evaluate gallium-67 (67Ga) uptake and the value of 67Ga scintigraphy for diagnosis of macrophagic myofasciitis (MMF), a recently identified inflammatory myopathy.

METHODS

Twelve consecutive patients with MMF confirmed by muscle biopsy, 10 with polymyositis, 10 with sarcoidosis, 8 with fibromyalgia, and 10 with lymphoma without muscle symptoms (serving as normal controls for muscle) were included. Patients received 1.8 MBq 67Ga per kg body weight by intravenous injection, and scintigraphy was performed with a 2-head gamma camera. The various views were acquired for the 3 main photopeaks of 67Ga 48 hours after infusion, and were analyzed in 2 blinded experiments by nuclear physicians. A semiquantitative scale was used to compare the uptake of 67Ga in the vascular soft tissue background with that in the muscles or joints of MMF patients, and with that in the normal controls.

RESULTS

The MMF patients (4 men and 8 women, mean +/- SD age 47.8 +/- 8.7 years) had chronic myalgia (n = 11; predominantly in the lower limbs), asthenia (n = 10), arthralgia (n = 7), mild muscle weakness (n = 5), and high serum creatine kinase levels (n = 6). All MMF patients had significantly higher levels of 67Ga uptake in the muscle and para-articular areas than that recorded for the soft tissue background and for the controls. Muscle uptake was bilateral, symmetric, and homogeneous, and predominantly localized in the legs. No linear enhancement corresponding to fascias or synovial involvement was observed. In patients with polymyositis, symmetric, but heterogeneous, 67Ga uptake was observed in muscle, but not in the fascia. In patients with sarcoidosis, 67Ga uptake was nodular and heterogeneous in muscle, was not detected in the fascia, and was suggestive of synovial involvement in the joints. The uptake of 67Ga in fibromyalgic patients was similar to that in normal controls and to that in the soft tissue background.

CONCLUSION

MMF is a new condition involving characteristic changes that can be detected by deltoid muscle biopsy. It usually manifests as a weakly specific, chronic arthromyalgic syndrome that predominates in the lower limbs. 67Ga scintigraphy is a noninvasive method that may make it easier to differentiate MMF from fibromyalgia and sarcoidosis.

Myoneurin, a novel member of the BTB/POZ-zinc finger family highly expressed in human muscle

Initially characterized as Drosophila developmental regulators, the BTB/POZ and zinc finger proteins (BTB/POZ-ZF) constitute a growing family of proteins with gene expression regulatory functions since they have been shown to be involved in both transcriptional activation and repression of various genes in a broad range of species, including mammals. Here we report the cloning of a novel human transcript, coding for a 68-kDa deduced BTB/POZ-ZF protein. This molecule, called myoneurin on the basis of its prevalent expression in the neuromuscular system, contains an amino-terminal BTB/POZ domain and eight tandemly repeated zinc-finger motifs of the C(2)H(2) type. The murine myoneurin, identified in the mouse embryo, is highly homologous to the human protein.

Bax and Bcl-2 interaction in a transgenic mouse model of familial amyotrophic lateral sclerosis

It has been proposed that mutations in copper/zinc-superoxide dismutase (SOD1), the only proven cause of amyotrophic lateral sclerosis (ALS), induce the disease by a toxic property that promotes apoptosis. Consistent with this, we have demonstrated that overexpression of Bcl-2, a protein that inhibits apoptosis, attenuates neurodegeneration produced by the familial ALS-linked SOD1 mutant G93A (mSOD1). Herein, we assessed the status of key members of the Bcl-2 family in the spinal cord of transgenic mSOD1 mice at different stages of the disease. In asymptomatic transgenic mSOD1 mice, expression of Bcl-2, Bcl-XL, Bad, and Bax does not differ from that in nontransgenic mice. In contrast, in symptomatic mice, expression of Bcl-2 and Bcl-XL, which inhibit apoptosis, is reduced, whereas expression of Bad and Bax, which stimulate apoptosis, is increased. These alterations are specific to affected brain regions and are caused by the mutant and not by the normal SOD1 enzyme. Relevant to the neuroprotective effects of Bcl-2 in transgenic mSOD1 mice, overexpression of Bcl-2 increases the formation of Bcl-2:Bax heterodimers, which abolish the Bax proapoptotic property. This study demonstrates significant alterations in the expression of key members of the Bcl-2 family associated with mSOD1 deleterious effects. That these changes contribute to the neurodegenerative process in this model of ALS is supported by our observations in double transgenic mSOD1/Bcl-2 mice in which the pernicious increase of Bax is tempered by an increase in formation of Bcl-2:Bax heterodimers. Based on these findings, it may be concluded that Bcl-2 family members appear as invaluable targets for the development of new neuroprotective therapies in ALS.

Insulin and phorbol ester regulation of gene 33 expression in CHO cells

Rat gene 33 (g33) mRNA has a widespread tissue distribution. Insulin and various agents such as glucocorticoids, phorbol esters and plant lectins regulate G33 expression in rat hepatoma cells. The regulation of g33 by insulin and a phorbol ester was examined in two Chinese Hamster ovary (CHO) cell lines, CHO-T cells (which overexpress human insulin receptors (hIR)) and wild type CHOwt cells. These cell lines were used to determine how expression of the hIR influences the capacity of g33 to respond to insulin and phorbol myristate acetate (PMA). Treatment of CHOwt and CHO-T cells with insulin increased mRNAg33 levels three to four-fold, with a maximum effect reached after three hours of treatment. PMA treatment of CHOwt and CHO-T cells caused a similar elevation of mRNAg33 levels after three hours. Insulin had no effect on mRNAg33 stability in both CHO cell lines. Additionally, the effects of insulin and PMA on mRNAg33 levels were additive only in CHO-T cells. Insulin or PMA-pretreated CHO-T cells were able to respond to both agents, but elevation of mRNAg33 levels was submaximal. In contrast, when insulin and/or PMA-pretreated CHOwt cells were exposed to insulin or PMA, g33 was able to respond maximally. These results suggest that insulin and phorbol esters act through different signaling mechanisms in CHOwt cells. Additionally, insulin's ability to stimulate g33 expression in CHOwt cells suggests that this insulin effect may be independent of the insulin receptor. There are differences in the regulation pattern of g33 by insulin and PMA in rat hepatoma and among the two CHO cell lines used in this study.

Diffusion of peroxynitrite in the presence of carbon dioxide

Peroxynitrite, the reactive species formed in vivo by the reaction of nitric oxide with superoxide anion, is capable of diffusing across erythrocyte membranes via anion channels and passive diffusion (A. Denicola, J. M. Souza, and R. Radi, Proc. Natl. Acad. Sci. USA 95, 3566-3571, 1998). However, peroxynitrite diffusion could be limited by extracellular targets, with the reaction with CO(2) (k(2) = 4.6 x 10(4) at 37 degrees C and pH 7.4) the most relevant. Herein, we studied the influence of physiological concentrations of CO(2) on peroxynitrite diffusion across intact red blood cells. The presence of CO(2) inhibited the oxidation of intracellular oxyhemoglobin by externally added peroxynitrite. However, the inhibition by CO(2) decreased at increasing red blood cell densities. At 45% hematocrit, 1.3 mM CO(2) (in equilibrium with 24 mM bicarbonate, at pH 7.4 and 25 degrees C) only inhibited 30% of intracellular oxyhemoglobin oxidation. This partial inhibition was also observed in red blood cells pretreated with the anion exchanger inhibitor 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid, ruling out a competition between peroxynitrite and bicarbonate for the transport through the anion channel. A theoretical model was developed to estimate the diffusion distance and half-life of extracellular peroxynitrite before reacting with intracellular oxyhemoglobin, at different red blood cell densities, and in the presence or absence of CO(2). The theoretical model correlated well with the experimental data. Our results indicate that, even in the presence of CO(2), peroxynitrite is able to diffuse and reach the inside of the erythrocyte.

Inducible nitric oxide synthase up-regulation in a transgenic mouse model of familial amyotrophic lateral sclerosis

Mutations in copper/zinc superoxide dismutase (SOD1) are associated with a familial form of amyotrophic lateral sclerosis (ALS), and their expression in transgenic mice produces an ALS-like syndrome. Here we show that, during the course of the disease, the spinal cord of transgenic mice expressing mutant SOD1 (mSOD1) is the site not only of a progressive loss of motor neurons, but also of a dramatic gliosis characterized by reactive astrocytes and activated microglial cells. These changes are absent from the spinal cord of age-matched transgenic mice expressing normal SOD1 and of wild-type mice. We also demonstrate that, during the course of the disease, the expression of inducible nitric oxide synthase (iNOS) increases. In both early symptomatic and end-stage transgenic mSOD1 mice, numerous cells with the appearance of glial cells are strongly iNOS-immunoreactive. In addition, iNOS mRNA level and catalytic activity are increased significantly in the spinal cord of these transgenic mSOD1 mice. None of these alterations are seen in the cerebellum of these animals, a region unaffected by mSOD1. Similarly, no up-regulation of iNOS is detected in the spinal cord of age-matched transgenic mice expressing normal SOD1 or of wild-type mice. The time course of the spinal cord gliosis and iNOS up-regulation parallels that of motor neuronal loss in transgenic mSOD1 mice. Neuronal nitric oxide synthase expression is only seen in neurons in the spinal cord of transgenic mSOD1 mice, regardless of the stage of the disease, and of age-matched transgenic mice expressing normal SOD1 and wild-type mice. Collectively, these data suggest that the observed alterations do not initiate the death of motor neurons, but may contribute to the propagation of the neurodegenerative process. Furthermore, the up-regulation of iNOS, which in turn may stimulate the production of nitric oxide, provides further support to the presumed deleterious role of nitric oxide in the pathogenesis of ALS. This observation also suggests that iNOS may represent a valuable target for the development of new therapeutic avenues for ALS.

Respiratory chain deficiency presenting as recurrent myoglobinuria in childhood

Myoglobinuria is an abnormal urinary excretion of myoglobin due to an acute destruction of skeletal muscle fibres. Several metabolic diseases are known to account for myoglobinuria including defects of glycolysis and fatty acid oxidation. Here, we report on respiratory chain enzyme deficiency in three unrelated children with recurrent episodes of myoglobinuria and muscle weakness (complex I: one patient, complex IV: two patients). All three patients had generalized hyporeflexia during attacks, a feature which is not commonly reported in other causes of rhabdomyolysis. Studying respiratory chain enzyme activities in cultured skin fibroblasts might help diagnosing this condition, especially when acute rhabdomyolysis precludes skeletal muscle biopsy during and immediately after episodes of myoglobinuria.

Lupus pernio with involvement of nasal cavity and maxillary sinus

Histological demonstration of sarcoidosis affecting the paranasal sinus is rare in the clinical practice. In this paper, we present a case with a diagnosis of lupus pernio with extensive involvement of the nasal cavity and the right maxillary sinus. Long before being diagnosed as having lupus pernio, the patient had had a long history of nasal obstruction and had been treated surgically without success on 3 occasions. The literature on the topic is reviewed.

Mutational diversity and hot spots in the alpha-sarcoglycan gene in autosomal recessive muscular dystrophy (LGMD2D)

Sarcoglycanopathies are a genetically heterogeneous group of autosomal recessive muscular dystrophies in which the primary defect may reside in any of the genes coding for the different partners of the sarcolemmal sarcoglycan (SG) complex: the alpha-SG (LGMD2D at 17q21.2), the beta-SG (LGMD2E at 4q12), the gamma-SG (LGMD2C at 13q12), and the delta-SG (LGMD2F at 5q33). We report a series of 20 new unrelated families with 14 different mutations in the alpha-SG gene. Along with the mutations that we previously reported this brings our cohort of patients with alpha-sarcoglycanopathy to a total of 31 unrelated patients, carrying 25 different mutations. The missense mutations reside in the extracellular domain of the protein. Five of 15 missense mutations, carried by unrelated subjects on different haplotype backgrounds and of widespread geographical origins, account for 58% of the mutated chromosomes, with a striking prevalence of the R77C substitution (32%). The severity of the disease varies strikingly and correlates at least in part with the amount of residual protein and the type of mutation. The recurrent R284C substitution is associated with a benign disease course.

[Microbiological study of some microorganisms implicated in sexually transmitted diseases among the female prison population]

BACKGROUND

Sexually transmitted diseases (STD) are of over greater interest, particularly since the appearance of the human immunodeficiency virus ( HIV) in the last decade. Asymptomatic or oligosymptomatic infections are very frequent, overall in women. The aim of this study was to know the prevalence of certain STD producing microorganisms in a female penitentiary population, the clinical characteristics and evaluate the risk factors which may be found in this population.

METHODS

One hundred thirty-three female prisoners attended in the Gynecology Ward of the Female Penitentiary of Carabanchel of Madrid, Spain, were studied over 13 months (from 30 April 1993 to 30 May, 1994). Vaginal and endocervical samples were taken in each case for microbiologic study by the usual methods. Demographic and clinical data were collected as were possible risk factors for acquiring STD (age of first sexual relations, sexual habits, intravenous drug addiction.

Recessive Schwartz-Jampel syndrome (SJS): confirmation of linkage to chromosome 1p, evidence of genetic homogeneity and reduction of the SJS locus to a 3-cM interval

Schwartz-Jampel syndrome (SJS), or chondrodystrophic myotonia, is a rare autosomal recessive disorder characterized by generalized myotonia resulting in a particular, recognizable facies and osteoarticular abnormalities. Some of us have recently shown genetic linkage of SJS to a locus on 1p34-p36.1 in five families. Here, we show by homozygosity mapping and segregation analysis that eight new families are most likely linked to the SJS locus on chromosome 1, confirming the localization of SJS to chromosome 1p and suggesting genetic homogeneity. Recombination events reduced the SJS locus from a genetic interval of 8 to 3 cM, which should facilitate the identification of the SJS gene. Low clinical variability was observed between the studied families, except for osteoarticular abnormalities. Since the severity and the location of osteoarticular abnormalities varied from one individual to another, even in the same families, other factors than the SJS gene itself, genetic or epigenetic, might contribute to the phenotype.

Vertical Flux of Biogenic Carbon in the Ocean: Is There Food Web Control?

Models of biogenic carbon (BC) flux assume that short herbivorous food chains lead to high export, whereas complex microbial or omnivorous food webs lead to recycling and low export, and that export of BC from the euphotic zone equals new production (NP). In the Gulf of St. Lawrence, particulate organic carbon fluxes were similar during the spring phytoplankton bloom, when herbivory dominated, and during nonbloom conditions, when microbial and omnivorous food webs dominated. In contrast, NP was 1.2 to 161 times greater during the bloom than after it. Thus, neither food web structure nor NP can predict the magnitude or patterns of BC export, particularly on time scales over which the ocean is in nonequilibrium conditions.

Prenatal diagnosis of limb-girdle muscular dystrophy type 2A

A branch of a highly inbred family was referred for prenatal counseling with an initial misdiagnosis of Becker Muscular Dystrophy (BMD) due to the limited clinical and laboratory data obtained in pre-dystrophin era and hidden family information. In a second branch of the family with a diagnosis of limb-girdle muscular dystrophy type 2A (LGMD2A) molecular studies revealed a homozygous 550 delta A mutation in the calcium-activated neutral protease 3 (calpain 3, CANP3) gene in the affected members. Finally, in the third branch of the family, it turned out that both parents were heterozygous for the 550 delta A mutation and the 13-week-old fetus was homozygous. The same mutation subsequently also was found in the first branch of the family. The parents were informed that the risk of their child of developing the disease would be very high given that he was carrying the same homozygous mutation of the other affected members. They were informed also that in another population (in Reunion Island) the same disease does not necessarily follow such a simple pattern of inheritance. After counseling the parents decided to terminate the pregnancy.

[Fatty acid composition and cholesterol content in naturally canned jurel, sardine, salmon, and tuna]

To obtain more information about fatty acid profile and cholesterol content of fat extracted from canned fish in brine habitually consumed in Chile, four different species Jurel (Trachurus murphyi), Sardine (Sardinops sagax), Salmon (Oncorhynchus kisutch) and Tuna (Thunnus alalunga) were analyzed. The GLC of fatty acid methyl esters showed that the main group of fatty acids belongs to polyunsaturated, being omega-3 family the more important. The principal representants were eicosapentaenoic (EPA) and docosahexaenoic acids (DHA), with percentages between 5%-11% and 12%-22% respectively. Omega-6 family was represented mainly by arachidonic acid (AA) with percentages between 2%-4%. Cholesterol content was similar to the values found in other animal origen meats. The figures were between 41-86 mg of cholesterol per 100 g of edible product, Tuna in brine, was the product with the lowest content of cholesterol. The calculated amount of EPA, DHA and total omega-3 fatty acids indicated values between 95-604, 390-1163 and 609-2775 mg respectively per 100 g of edible product. Due these results is important to emphasize the consumption of this type of canned fish in brine, that they really represent a good dietary source of mainly polyunsaturated omega-3 fatty acids. The international recommendations indicate to increase the consumption of fish, due the beneficial effects described in relation with cardiovascular disease, which is the mean cause of death in Chile, country with a wide variety of marine origen foods, but with a contradictory answer about its consumption which is not incorporated in the current diet.

Localization of the Schwartz-Jampel syndrome (SJS) locus to chromosome 1p34-p36.1 by homozygosity mapping

Schwartz-Jampel syndrome (SJS, MIM 255800), also known as chondrodystrophic myotonia, is a rare autosomal recessive disorder characterized by generalized myotonia, skeletal abnormalities and facial dysmorphism. Using homozygosity mapping, we localized the SJS locus to chromosome 1p34-p36.1 in a 8 cM interval flanked by markers D1S199 and D1S234. Families of different ethnic backgrounds (Tunisia and South Africa) showed genetic linkage to the same locus. Moreover, one Algerian family also demonstrated evidence of genetic linkage to 1p34-p36.1. Taken altogether, our results suggest genetic homogeneity, at least in the group of families analyzed.

[An analysis of the nasolabial angle]

We analyzed the nasolabial angle and different factors that influence it in patients of 9.0 +/- 1.4 years of age. An average value of 115.30 +/- 10.8 was obtained. The inclination and the position of the upper incisive and the ANB angle constituted the osseous and dental factors with greatest repercussion on the nasolabial angle. Sex and age did not condition significant differences. The labial incompetence determined a more acute angle.

[The association between arterial hypertension, obesity and hypercholesterolemia in a sample of the adult population of Catalonia]

BACKGROUND

The Framingham's study has demonstrated that the incidence of cardiovascular diseases increases when several risk factors are present. In this study, the association between the main cardiovascular risk factors has been studied in a random sample from the adult population of Catalonia.

METHODS

A random sample was obtained (n = 314) from the adult population of Catalonia and univariate and multivariate statistical procedures were used to analyze the association between the following risk factors: HDL, hypertriglyceridemia, obesity, diabetes and tobacco consumption.

RESULTS

A simple correlation was observed between most of the risk factors. The multiple linear regression analysis showed that both the diastolic and systolic arterial pressures were correlated with total levels of cholesterol, body mass index and age (r = 0.65 for SAP and r = 0.48 for DAP); levels of total cholesterol were correlated with levels of triglycerides and age (r = 0.57); levels of triglycerides were correlated with levels of total cholesterol and cholesterol-HDL, body mass index and age (r = 0.61); body mass index was correlated with levels of triglycerides, total cholesterol, cholesterol-HDL and age (r = 0.52) (p < 0.001). The prevalence of hypercholesterolemia, obesity and diabetes was higher and the prevalence of tobacco consumption was lower among the hypertensives (SAP > 140 and/or DAP > 90 mm Hg) than among normotensives, being the odds ratio 3.56 (2-6.33) for hypercholesterolemia; 3.65 (1.66-8.09) for obesity; 3.70 (1.06-13.45) for diabetes and 0.40 (0.22-0.72) for tobacco consumption. The adjusted odds ratio derived from multiple logistic regression analysis was 2.52 (1.38-4.64) for hypercholesterolemia; 2.40 (1.05-5.46) for obesity, 1.74 (0.50-6.04) for diabetes and 0.63 (0.33-1.20) for tobacco consumption, being statistically significant in the case of hypercholesterolemia (p = 0.002) and obesity (p = 0.038).

CONCLUSION

We have observed an association between the cardiovascular risk factors analyzed. This association may be attributed to several physiological mechanisms and life-styles, which may influence the development of atherosclerosis and increase the cardiovascular risk.

Teaching family and community dimensions of clinical family medicine in Venezuela

BACKGROUND AND OBJECTIVES

In Venezuela, family medicine is taught and practiced almost exclusively in ambulatory care settings. This article describes the evolution of the educational strategies that emphasize family and community aspects of clinical practice within one residency program in the country of Venezuela.

METHODS

Three distinct phases of development are depicted, beginning with a biomedical and individual-centered approach. Subsequent efforts to involve residents in the community provoked criticism. Resident-faculty dialogue led to modifications and to the success of the current program. Some of the specific educational strategies are: a structured weekly five-hour community afternoon, a 40-hour course titled "Family Dynamics and Counseling," use of the family-oriented home visit to introduce residents to the community aspects of health care, and completion of a community-based and health-related project.

RESULTS

A sample of residents and graduates noted an improved doctor-patient relationship, improved ability to work with groups, and improved skills for incorporating preventive medicine with a community focus into their clinical practice.

CONCLUSIONS

The community involvement is enthusiastically supported by the residents, as it is perceived as useful for clinical practice. The program prepares family physicians to become more responsive to the health needs and the reality of Venezuelan society.

Whole-body autoradiographic disposition, elimination and placental transport of [14C]tri-o-cresyl phosphate in mice

Tri-o-cresyl phosphate (TOCP) is used commercially as a plasticizer and flame retardant. The disposition, metabolism, elimination and transplacental uptake of [phenyl-U-14C]TOCP and/or its metabolites, in pregnant and non-pregnant mice, were examined. Pregnant (18th-day gestation) and non-pregnant, ICR mice were given an i.v. dose of [14C]TOCP (557 microCi kg-1; Specified activity 4.83 microCi mumol-1). At various time intervals (1, 24, 48 and 72 h) the animals were processed for whole-body autoradiography (WBA). Over 72 h the non-pregnant mice excreted 55% of the 14C in the urine and 9% in the feces, while excretion in the urine and feces by the pregnant mice was 50% and 9% of the total dose, respectively. The WBA and its computer-assisted image analysis indicated extensive distribution of the 14C label originally dosed as [14C]TOCP in pregnant mice and their fetuses. The retention of radioactivity in organs such as lung, spleen, gall-bladder and liver of mother and its fetuses suggest that these are the target sites of TOCP toxicity. The distribution in non-pregnant and pregnant mice and in the fetal tissues followed a similar pattern in uptake and retention until 72 h. Brain and spinal cord had the least amount of [14C]TOCP. This finding may support reports that explain the insensitivity of the mice towards organophosphate-induced delayed neurotoxicity (OPIDN) of TOCP.

In vitro studies on the growth of Shigella sonnei by Lactobacillus casei and Lact. acidophilus

The inhibitory effect of lactobacilli on growth of Shigella sonnei was studied. The effect was not due to pH alone, as addition of hydrochloric, lactic or acetic acids to culture media did not inhibit the normal growth of the shigellas. The degree of inhibition was measured by disc assay and showed that the inhibitory substance(s) can be extracellular and diffusible, varying the degrees of inhibition depending on the media tested. When broth was inoculated with mixed cultures of Lactobacillus and Shigella strains, the inhibition began at 6 h and the death phase at 9 h. The higher inhibition was produced by the mixture of lactobacilli (35.5 +/- 2.5% at 6 h culture, 57.4 +/- 1.9% at 9 h and 91.2 +/- 1.2% at 14 h). The degree of inhibition was higher when the relationship pathogen : lactobacilli was 1:10(3). The specific growth rate of lactobacilli and shigella was different in pure or mixed cultures. When the lactobacillus alone was grown for 12 h and the shigellas then added, the numbers of shigellas began to decrease immediately at 37 degrees C. This work shows that the Lactobacillus strains employed in fermented milk can be used to inhibit the growth of Sh. sonnei.

Maternally inherited duplication of the mitochondrial genome in a syndrome of proximal tubulopathy, diabetes mellitus, and cerebellar ataxia

Two sisters in the first year of life presented with a proximal tubulopathy of unknown etiology. They subsequently developed a pluritissular disorder including diabetes mellitus, skin abnormalities, mitochondrial myopathy with ragged-red fibers, and cerebellar ataxia. Their mother had ptosis, ophthalmoplegia, and muscle weakness. Analysis of the mitochondrial respiratory chain showed a complex III deficiency in both skeletal muscle and lymphocytes of the second girl. Southern blot analysis provided evidence for a heteroplasmic partial duplication of the mtDNA (26 kb), involving one full-length and one partly deleted mitochondrial genome and with one single abnormal junction between the genes for ATPase 6 and cytochrome b. Using PCR amplification of lymphocyte DNA, we were able to detect minute amounts of duplicated molecules in the mother, which provided evidence for maternal inheritance of the partial duplication. While maternal transmission of point mutations have been reported in Leber disease, retinitis pigmentosa, and MERRF disease, this observation is, to our knowledge, the first example of a maternally inherited duplication of the mitochondrial genome in man.

Genetic biochemical and pathophysiological characterization of a familial mitochondrial encephalomyopathy (MERRF)

Myoclonic epilepsy with ragged-red fibers (MERRF) syndrome is a neuromuscular disorder characterized by mitochondrial myopathy and progressive myoclonus epilepsy. A heteroplasmic A to G transition mutation in the mitochondrial encoded tRNA(Lys) gene at nucleotide pair 8344 has been suggested to be linked to the MERRF-syndrome. We have investigated biochemically and histochemically muscle biopsies and studied the mitochondrial genomes of hair, blood and muscle tissue of a family including three cases of MERRF-syndrome as well as unaffected relatives within the maternal lineage. Sequence analysis of the mtDNAs, performed after amplification by the polymerase chain reaction (PCR), confirmed the A to G transition mutation in the tRNA(Lys) gene at position 8344. The additional point mutation at nucleotide pair 750 in the 12 S rRNA gene, which was also found by Shoffner et al. (1990), however, was absent in all investigated tissues. Quantitative analysis of the percentage of mutated mtDNA by mispairing PCR (Seibel et al., 1990) revealed variable contents in different tissues and individuals, including unaffected family members. Mitochondrial protein synthesis in cultured fibroblasts from MERRF patients revealed diminished incorporation of 35S-methionine into lysine-containing peptides.

Autosomal dominant syndrome with strokelike episodes and leukoencephalopathy

BACKGROUND AND PURPOSE

We conducted a prospective survey of a family presenting a new syndrome characterized mainly by recurrent strokelike episodes and neuroimaging evidence of leukoencephalopathy.

SUMMARY OF REPORT

Forty-five members of a single family were studied clinically and with magnetic resonance imaging. Nine had strokelike episodes, including transient ischemic attacks, and minor or major strokes starting between the fourth and sixth decades, with neuroimaging evidence of small, deep infarcts and a widespread white matter disorder. Other symptoms included migraine (three), dementia (two), epilepsy (one), and hearing loss (one). In some patients, we found various immunologic anomalies and muscular lipidosis without ragged-red fibers. Eight other family members were clinically normal, but had identical neuroimaging signs of leukoencephalopathy. No abnormality was detected in the 28 other members of the family examined. Extensive investigations failed to reveal any known cause of cerebral ischemia.

CONCLUSIONS

There appears to be a new syndrome in this family that is characterized by recurrent subcortical strokelike episodes, leukoencephalopathy, immunologic anomalies, muscular lipidosis, and an autosomal dominant pattern of transmission.

Different mechanisms inferred from sequences of human mitochondrial DNA deletions in ocular myopathies

We have sequenced the deletion borders of the muscle mitochondrial DNA from 24 patients with heteroplasmic deletions. The length of these deletions varies from 2.310 bp to 8.476 bp and spans from position 5.786 to 15.925 of the human mitochondrial genome preserving the heavy chain and light chain origins of replication. 12 cases are common deletions identical to the mutation already described by other workers and characterized by 13 bp repeats at the deletion boundaries, one of these repeats being retained during the deletion process. The other cases (10 out of 12) have shown deletions which have not been previously described. All these deletions are located in the H strand DNA region which is potentially single stranded during mitochondrial DNA replication. In two cases, the retained Adenosine from repeat closed to the heavy strand origin of replication would indicate slippage mispairing. Furthermore in one patient two mt DNA molecules have been cloned and their sequences showed the difference of four nucleotides in the breakpoint of the deletion, possibly dued to slippage mispairing. Taken together our results suggest that deletions occur either by slippage mispairing or by internal recombination at the direct repeat level. They also suggest that different mechanisms account for the deletions since similarly located deletions may display different motives at the boundaries including the absence of any direct repeat.

Deletions of mitochondrial DNA in Kearns-Sayre syndrome and ocular myopathies: genetic, biochemical and morphological studies

Genetic, biochemical and morphological investigations were conducted on skeletal muscle mitochondria from 6 cases of ocular myopathy: 4 cases with Kearns-Sayre syndrome (KSS) and 2 with chronic progressive external ophthalmoplegia. All of these 6 cases showed mitochondrial DNA (mtDNA) deletions in addition to normal sized DNA in the quadriceps muscle. The deletions ranging from 3 to 8 kbp were also mapped between nucleotides 5500 and 16000 by Southern blot. The deleted genes encoded for some subunits of complexes I, IV, V and 5-10 tRNAS. The boundaries of the deletions have been sequenced in three patients. Five patients had mitochondrial respiratory chain deficiency in complex I as shown by the low oxygen consumption in isolated mitochondria using three NAD(+)-linked substrates. Mitochondria with an abnormal ultrastructure were also observed in 2 cases. A good relationship between the cytochrome c oxidase deficiency and the amount of deleted mtDNA was shown in our present investigations.

Identification of point mutations by mispairing PCR as exemplified in MERRF disease

The point mutation in the tRNA(Lys) gene of mitochondrial DNA (mtDNA) from patients with myoclonic epilepsy and ragged red fibers (MERRF) was quantitatively analyzed after digestion with the restriction endonuclease Nae I of the PCR amplified DNA. Since the point mutation is not part of a restriction site for a commonly available restriction endonuclease, the Nae I restriction site was introduced by PCR using a mispairing primer. The percentage of mutated mtDNA was determined in a few hairs of five members of an affected family by counting the radioactivity of the fragments after PCR amplification with labelled dATP.

Pearson's marrow-pancreas syndrome. A multisystem mitochondrial disorder in infancy

Pearson's marrow-pancreas syndrome (McKusick No. 26056) is a fatal disorder of hitherto unknown etiology involving the hematopoietic system, exocrine pancreas, liver, and kidneys. The observation of high lactate/pyruvate molar ratios in plasma and abnormal oxidative phosphorylation in lymphocytes led us to postulate that Pearson's syndrome belongs to the group of mitochondrial cytopathies. Since rearrangements of the mitochondrial genome between direct DNA repeats were consistently found in all tissues tested, our results show that this disease is in fact a multisystem mitochondrial disorder, as suggested by the clinical course of the patients. Based on these observations, we would suggest giving consideration to the hypothesis of a defect of oxidative phosphorylation in elucidating the origin of other syndromes, especially those associated with an abnormal oxidoreduction status in plasma.

Immunohistochemical demonstration of fibre type-specific isozymes of cytochrome c oxidase in human skeletal muscle

The immunohistochemical reaction of monoclonal as well as polyclonal antibodies against cytochrome c oxidase (COX) subunits with serial sections of normal human skeletal muscle was investigated. The stronger reactivity of polyclonal antibodies to COX subunits II-III and VIIbc with type I as compared to type II fibres, correlated well with the higher histochemical reactivity of NADH dehydrogenase, succinate dehydrogenase and cytochrome c oxidase in type I fibres. In contrast an almost exclusive reaction of a monoclonal antibody against subunit IV with type I fibre and a preponderant reaction of a polyclonal antibody against subunits Vab with type II fibres was obtained. Antibodies against subunits I, Vb and VIc did not reveal a fibre-type-specific reactivity. The data indicate in human muscle the occurrence of fibre type-specific isozymes of cytochrome c oxidase differing in subunits IV and Va or Vb.

Superoxide dismutase activity in some strains of lactobacilli: induction by manganese

Dialyzed cell-free extract of lactobacilli was found to contain superoxide dismutase activity by using a test system in which superoxide ion is generated by xanthine oxidase. The specific activities of Lactobacillus acidophilus ATCC 4356, Lactobacillus murinus ATCC 35020, Lactobacillus acidophilus CRL 358, Lactobacillus plantarum ATCC 8014, Lactobacillus casei CRL 431, Lactobacillus plantarum CRL 353, Lactobacillus fermentum ATCC 9338, Lactobacillus buchneri NCDO 110, and Lactobacillus fermentum CRL 251 were between 0.06 and 0.43 U/mg protein. The presence of superoxide dismutase activity was demonstrated when the strains were grown in media containing Mn2+ ions. Superoxide dismutase of lactobacilli may be an Mn enzyme since it was not inhibited by either cyanide or azide ions. However, the cell-free extract of Lactobacillus murinus ATCC 35020 contains superoxide dismutase activity sensitive to both ions.

[Respiratory chain diseases in infancy. Clinical presentation and diagnosis]

Nineteen children with defects of the mitochondrial respiratory chain are described. First symptoms appeared during the first two years of their lives. Four types of clinical pictures were identified: 1/neonatal hypotonia. 2/cardiomyopathy. 3/progressive neurological deterioration. 4/multisystem disease. A study of pyruvate and fatty acids metabolism and a skeletal muscle biopsy were performed in all cases. Elevation of beta-hydroxybutyrate/acetoacetate and lactate were the most frequent biochemical abnormalities. Muscular biopsy in light microscopy showed in most cases abnormal lipid storage.

Mapping of heteroplasmic mitochondrial DNA deletions in Kearns-Sayre syndrome

Kearns-Sayre syndrome (KSS) is a progressive neuromuscular disease characterised by ophtalmoplegia, cardiac bloc branch, pigmentary retinopathy associated with abnormal mitochondrial function. We have studied the mitochondrial DNA organization of patients presenting KSS and have found large deletions ranging from 3 to 8.5 kilobase pairs. DNA molecules containing deletion are accompanied by the presence of the normal sized mtDNA molecule forming heteroplasmic genomes. The deletions always map in the region which is potentially single stranded during mitochondrial DNA replication. The deletions differ in length and position between individuals but are similar within the different tissues of an individual suggesting that they arise during or before embryogenesis.

Effect of latissimus dorsi dynamic cardiomyoplasty on ventricular function

In our approach to dynamic cardiomyoplasty, which consists of wrapping a skeletal muscle around the heart and stimulating the former in synchrony with heart contractions to augment ventricular contractility, we have transferred a latissimus dorsi muscle flap to the heart by way of a partial resection of the second rib and subsequently suturing the muscle flap around the ventricles. The muscle flap is stimulated by a Cardio-Myostimulator burst-pulse generator (Medtronic SP 1005) connected to intramuscular electrodes. In preclinical animal research, the latissimus dorsi muscle flap was shown to maintain adequate contractile force and to increase its fatigue resistance by gradual conversion of glycolytic-fatigue-sensitive-to-oxidative-fatigue-resistant muscular fibers (100%). Histochemical and biochemical studies of chronically stimulated muscles showed a total transformation of muscle fast myosin to slow myosin with characteristics similar to those of myocardium. Electron microscopy showed preserved myofibrillar cytoarchitecture and increased mitochondrial density in the cell. At 9 months, cardiac output and ultrasonic Doppler studies showed a significant increase in ventricular function (cardiac output, +21%; peak blood velocity, +40% -80%; and stroke volume, +98% -102%) during muscle stimulation. In the clinical situation, long-term (range of follow-up interval, 4-42 months) beneficial cardiac effects of cardiomyoplasty have been documented in eight patients with various pathologies (ventricular tumor, left ventricular aneurysm, ischemic disease, and dilated cardiomyopathy). Our current understanding of this process is that dynamic cardiomyoplasty acts in two ways: 1) it promotes more vigorous systolic contraction, and 2) it appears to limit heart dilatation.

Role of copper in the regulation and accumulation of superoxide dismutase and metallothionein in rat liver

Weanling male Sprague-Dawley rats were fed one of four diets that varied in Cu, Zn or Cd content. To the control diet (I) Cu, Zn and Cd were added at 10, 100 and 0 mg/kg diet, respectively. Diets II and III also contained 10 mg/kg of dietary Cu, except that Zn was elevated to 1000 mg/kg for diet II, or Cd was added at 10 mg/kg for diet III. Diet IV was deficient in Cu (less than 1 mg/kg) with Zn at 100 mg/kg and no added Cd. At wk 6 postweaning, half of the rats fed diets I and IV were injected once with Cd acetate (5 mg Cd/kg body weight). The immediate response to Cd injection was an increase in metallothionein accumulation (three- to fourfold) and in Cu,Zn superoxide dismutase (SOD) accumulation (1.2- to 1.5-fold) in liver. SOD was estimated in an ELISA. These responses were not influenced by a change in Cu status (I vs. IV). However, in functional assays, SOD enzymatic activity was about half that of the control values. In this regard, SOD appears to be given high priority with respect to the utilization of cellular Cu, i.e., a 10-fold reduction in hepatic Cu only resulted in a twofold reduction in SOD activity and the amount of apoenzyme remained at normal levels.

Tropoelastin production and tropoelastin messenger RNA activity. Relationship to copper and elastin cross-linking in chick aorta

The elastin content of the chick thoracic aorta increases 2--3-fold during the first 3 weeks post-hatching. The deposition of elastin requires the covalent cross-linking of tropoelastin by means of lysine-derived cross-links. This process is sensitive to dietary copper intake, since copper serves as cofactor for lysyl oxidase, the enzyme that catalyses the oxidative deamination of the lysine residues involved in cross-link formation. Disruption of cross-linking alters tissue concentrations of both elastin and tropoelastin and results in a net decrease in aortic elastin content. Autoregulation of tropoelastin synthesis by changes in the pool sizes of elastin or tropoelastin has been suggested as a possible mechanism for the diminished aortic elastin content. Consequently, dietary copper deficiency was induced to study the effect of impaired elastin cross-link formation on tropoelastin synthesis. Elastin in aortae from copper-deficient chicks was only two-thirds to one-half the amount measured in copper-supplemented chicks, whereas copper-deficient concentrations of tropoelastin in aorta were at least 5-fold higher than normal. In spite of these changes, however, increased amounts of tropoelastin, copper deficiency and decreased amounts of elastin did not influence the amounts of functional elastin mRNA in aorta. Likewise, the production of tropoelastin in aorta explants was the same whether the explants were taken from copper-sufficient or -deficient birds. The lower accumulation of elastin in aorta from copper-deficient chicks appeared to be due to extracellular proteolysis, rather than to a decrease in the rate of synthesis. Electrophoresis of aorta extracts, followed by immunological detection of tropoelastin-derived products, indicated degradation products in aortae from copper-deficient birds. In extracts of aortae from copper-sufficient chicks, tropoelastin was not degraded and appeared to be incorporated into elastin without further proteolytic processing.

Role of plasma and serum proteases in the degradation of elastin

Accelerated proteolysis of tropoelastin and elastin occurs in the major arteries of chicks fed copper-deficient diets. Signs of elastin degradation are not obvious in normal arteries of copper-supplemented chicks. It is proposed that the sources of proteases that effect elastin degradation are from plasma and serum. Both calcium-dependent proteases and kallikrein were effective in degrading tropoelastin and partially crosslinked insoluble elastin into peptides similar to those detected in aortic extracts from copper-deficient chicks. As dietary copper deficiency progresses it is also possible to detect elastin peptides in plasma.

Haemodynamic effects of oral molsidomine in pump failure complicating myocardial infarction

Haemodynamic monitoring, using a Swan-Ganz balloon catheter, was done in 14 patients with pump failure associated with acute myocardial infarction, before and for 8 h after single 6 mg oral dose of molsidomine. The following changes effects were found: HR fell by 1.6 to 4.7% (significant at 4th hour; p less than 0.05); SBP was 8.4% lower after 1 h (p less than 0.05); PCP was decreased by approximately 30%, a significant effect that lasted for 8 hours (p less than 0.002). CI did not change significantly, although individual analysis showed it to have increased in 6 out of 12 cases. Stroke volume index was increased by about 6% (significant after 1 h, p less than 0.025). The left ventricular stroke work index also increased from 9.8 to 24.5% (significant after 1 and 4 h, p less than 0.01 and 0.025). These findings show the beneficial haemodynamic effects of molsidomine in pump failure complicating acute myocardial infarction.