Epidemiology and prophylaxis of endemic goitre in the Bwa village of Sirao (Mali)

A study was conducted in Mali, in some villages exposed to iodine deficiency disorders (IDD). To treat and, above all, prevent endemic goitre, Lipiodol UF was dispensed in two ways: by intra-muscular injection (475 mg I) or by oral administration (48 mg I to 240 mg I). In two cases, hormone levels regained normal values and thyroid hypertrophies regressed significantly. Nevertheless, the impact of the treatment on the size of the goitres seems to be in favour of injections; which is probably due to the fact that in the village which received Lipiodol UF per os, many goitres were nodular.     

NADP+-isocitrate dehydrogenase in germinating and senescing pumpkin cotyledons

NADP⁺-isocitrate dehydrogenase (IDH, EC 1.1.1.42) was studied during the post-germinative growth of pumpkin ( Cucurbita pepo L. cv. Alberello di Sarzana) seedlings. In cotyledons. IDH activity increased in the dark and declined after illumination. Native PAGE showed that at least two isozymes of low electrophoretic mobility are present in cotyledons and absent in other pumpkin tissues. Anion exchange chromatography performed on extracts both from 4-day-old etiolated cotyledons and from illuminated cotyledons confirmed the trend of the IDH isoforms. In senescing cotyledons an additional IDH isoform with higher electrophoretic mobility appears. Overall the data indicate the presence of specific NADP⁺-IDH isoforms in etiolated cotyledons and senescing cotyledons, when glyoxylate cycle enzymes are active. A possible role for these IDH isoforms is proposed.     

On the mode of evolution of alpha satellite DNA in human populations

Summary The hypothesis that highly reiterated satellite DNAs in present-day populations evolve by molecular mechanisms that create, by saltatory amplification steps, new long arrays of satellite DNA, and that such long arrays are used for homogenization purposes, has been tested both in mouse and in humans. In mouse, the data obtained are consistent with this hypothesis. This was tested in more detail on chromosomes 13 and 21 of the human genome. A Centre d'Etudes du Polymorphisme Humain family, which in some individuals exhibits strong supplementary DNA bands following TaqI restriction endonuclease digestion and conventional gel electrophoresis, was analyzed by pulse field gel electrophoresis following restriction by BamHI. The supplementary bands on chromosome 13 (18 times the basic alpha satellite DNA repeat) and on chromosome 21 (a 9.5-mer) segregated with centromeric alpha satellite DNA blocks of 5 and 5.3 megabases, respectively. These are by far the largest alpha satellite block lengths seen in all chromosome 13 and chromosome 21 centrometric sequences so far analyzed in this manner. The possibility that these supplementary alpha satellite sequences were created in single individuals by saltatory amplification steps is discussed in light of our own data and that published by others. It is proposed that deletion events and unequal cross-overs, which both occur in large satellite DNA arrays, contribute to the homogenization of size and sequence of the alpha satellite DNA on most chromosomes of humans.     

A fast atom bombardment-mass spectrometric method to quantitate lysophosphatidylserine in rat brain

A method to quantitate lysophosphatidylserine by fast atom bombardment-mass spectrometry using 1-hexa-decanoyl-sn-glycero-3-phospho-L-serine as internal standard is described. The standard curve is linear with a correlation coefficient r2 = 0.999 from 10 to 1000 ng. This curve has been used to quantitate LPS in rat brain using phosphorus assay as a test control. We found 475 +/- 70 ng of LPS in 1 mg of tissue (n = 3). This method presents advantages due to its sensitivity and its capability to give molecular information of the unmodified compound.     

Cloning and characterization of barley long chain acyl-CoA oxidase and its possible regulation by glucose

A barley ( Hordeum vulgare L.) full-length clone coding for long chain acyl-CoA oxidase (ACX), key enzyme of β -oxidation, was isolated by cDNA library screening and 5'-rapid amplification of cDNA ends. The cDNA encodes for a polypeptide of 667 amino acids, with a molecular mass of 74.5 kDa. The amino acid sequence, beside an extensive similarity with other plant and mammalian ACXs, showed a PTS1 peroxisomal targeting signal at the C terminus and a conserved FAD-binding domain. The gene was over-expressed in E. coli and the fusion protein was shown to possess long chain acyl-CoA oxidase activity. Polyclonal antibodies were raised against a large fragment of the protein encoded by the barley putative ACX gene. Northern and Western analysis demonstrated that a basal level of long chain ACX is always present along the barley life cycle, while a higher level of expression is typical of actively growing tissues such as germinating embryos, ovary before anthesis, developing embryos, shoots and roots apexes. In vitro germination experiments with glucose and glucose analogues provided evidence about the involvement of a glucose-deriving signal in the positive modulation of ACX expression. This result highlights the role of ACX, not only during oil reserve mobilization, but also in plant growth and metabolism.     

3'' Alu PCR: a simple and rapid method to isolate human polymorphic markers.

Microsatellites, such as (TG)n found at random throughout the genome, or as 3' extensions of Alu sequences are being increasingly used as genetic markers because of their pluriallelic character. The search for polymorphic microsatellites is time consuming, however, as it is necessary to sequence clones containing the microsatellites sequences in order to design specific PCR primers before testing for polymorphism, which does not always occur. We propose here a new approach to generate polymorphic markers, based on the amplification of microsatellites at the 3' end of Alu sequences, without the need for cloning or sequencing steps.     

Growth factors in the human prostate

Recent studies have focused on the potential role of local polypeptide growth-regulating factors in the etiology of benign prostatic hyperplasia (BPH) and prostatic carcinoma. In our studies we confirmed the presence of specific receptors for epidermal growth factor (EGF) in prostatic tissues from patients affected by BPH. In addition, we demonstrated that specific receptors for insulin-like growth factor type I (IGF-I) are present in BPH tissues. In order to identify a possible interaction between androgens and these growth-regulating factors, we investigated the effect of testicular suppression-induced androgen withdrawal on both EGF and IGF-I receptor concentrations in prostatic tissue from patients affected by BPH treated with a long-acting luteinizing hormone-releasing hormone analog. Both EGF and IGF-I binding capacities were significantly increased after treatment. This finding suggests that in vivo IGF-I and EGF receptor levels may be under negative androgenic regulation, indicating a potential role for these growth-regulating factors in the mechanism of response to the castration-induced regression of androgen-dependent prostatic tissue. Moreover, preliminary studies indicate that in human BPH prostatic tissue multiple IGF-binding proteins (IGF-BP) are present. This finding suggests a possible role of IGF-BP in modulating IGFs biological activities at the prostate level.     

Comparative study of the L1 family in the genus Mus. Possible role of retroposition and conversion events in its concerted evolution

The long interspersed repetitive family L1 was analysed in different species belonging to the genus Mus. It is shown to be highly conserved even in M.n. setulosus, which diverged from the other species around ten million years ago. The study of the linkage between diagnostic restriction sites in the various species and the sequence variations of different regions of the L1Md repeat shows that the L1 family undergoes concerted changes involving subsets of repeats. The rate at which this homogenization process occurs does not appear to be the same for all the subfamilies detected. The L1Md repeat in the twelfth intron of the serum albumin gene of Balb/c mice is shown to be a recent insertion. The role retroposon- and gene conversion-like events may play in the concerted evolution of the L1 family is discussed.     

Distributions of two recently inserted long interspersed elements of the L1 repetitive family at the Alb and beta h3 loci in wild mice populations

The presence of the L1 sequences, L1Md4 next to the pseudogene beta h3 and I12 found in the twelfth intron of the albumin gene, in certain strains of laboratory mice but not of others has led to the suggestion that these sequences were recent insertions into the Mus mus domesticus genome. To be sure that they are really recent insertions and not relics of an ancestral chromosome, we investigated the presence or absence of these sequences in populations of wild mice belonging to the semispecies M. m. domesticus and M. m. musculus as well as in other species of the genus Mus and in related murids. The sequence I12 in the albumin gene was found in 34% of the chromosomes of the wild mice belonging to M. m. domesticus and to a lesser extent (6%) in M. m. musculus. Of 114 M. m. domesticus chromosomes, L1Md4 was found in only nine, seven of which came from the same locality. Its presence was associated with the haplotype Hbbp, which is relatively rare in European populations of M. musculus. Since there was no evidence for the presence of these two L1 sequences in more distantly related species, we conclude that they are recent insertions in the M. musculus genome.      

Tempo and mode of concerted evolution in the L1 repeat family of mice

A 300-bp DNA sequence has been determined for 30 (10 from each of three species of mice) random isolates of a subset of the long interspersed repeat family L1. From these data we conclude that members of the L1 family are evolving in concert at the DNA sequence level in Mus domesticus, Mus caroli, and Mus platythrix. The mechanism responsible for this phenomenon may be either duplicative transposition, gene conversion, or a combination of the two. The amount of intraspecies divergence averages 4.4%, although between species base substitutions accumulate at the rate of approximately 0.85%/Myr to a maximum divergence of 9.1% between M. platythrix and both M. domesticus and M. caroli. Parsimony analysis reveals that the M. platythrix L1 family has evolved into a distinct clade in the 10-12 Myr since M. platythrix last shared a common ancestor with M. domesticus and M. caroli. The parsimony tree also provides a means to derive the average half-life of L1 sequences in the genome. The rates of gain and loss of individual copies of L1 were estimated to be approximately equal, such that approximately one-half of them turn over every 3.3 Myr.