Studies on the influence of photoreactivation on the frequencies of UV-induced chromosomal aberrations, sister-chromatid exchanges and pyrimidine dimers in chicken embryonic fibroblasts

Chicken embryonic fibroblasts, which possess photoreactivating enzyme were used to study the influence of photoreactivating light on the induction of pyrimidine dimers, sister-chromatid exchanges (SCEs) and chromosomal aberrations by 254 nm UV. While photoreactivation (PR) efficiently removed most of the induced dimers (75-95%), the frequencies of SCEs and chromosomal aberrations were reduced only by about 30-65%, in parallel experiments. Since pyrimidine dimers are the only photoreactivable photolesions known, the reduction in the frequencies of SCEs and chromosomal aberrations on PR has been interpreted as due to disappearance of pyrimidine dimers, implying that these lesions are the primary events responsible for the induction of the biological end points studied. The possible reasons for the lack of quantitative relationship between the frequencies of dimers and the frequencies of SCEs and chromosomal aberrations are discussed.     

Ragweed presence in Trieste: clinical and aerobiological data

Summary Studies on ragweed have been carried out in the province of Trieste (Northern Italy) in which it is becoming widespread. The floristic records, the increasing amount of airborne pollen monitored and the relevant skin reactivity are reported. This phenomenon, though still at the beginning, is actually showing an upward trend due to man's intervention over wider and wider areas which as a consequence become suitable for the settlement of these anthropophitic species. The aerobiological data are compared to the skin reactivities of allergic subjects.     

High-resolution Y chromosome haplotypes of Israeli and Palestinian Arabs reveal geographic substructure and substantial overlap with haplotypes of Jews

High-resolution Y chromosome haplotype analysis was performed in 143 paternally unrelated Israeli and Palestinian Moslem Arabs (I&P Arabs) by screening for 11 binary polymorphisms and six microsatellite loci. Two frequent haplotypes were found among the 83 detected: the modal haplotype of the I&P Arabs (approximately 14%) was spread throughout the region, while its one-step microsatellite neighbor, the modal haplotype of the Galilee sample (approximately 8%), was mainly restricted to the north. Geographic substructuring within the Arabs was observed in the highlands of Samaria and Judea. Y chromosome variation in the I&P Arabs was compared to that of Ashkenazi and Sephardic Jews, and to that of North Welsh individuals. At the haplogroup level, defined by the binary polymorphisms only, the Y chromosome distribution in Arabs and Jews was similar but not identical. At the haplotype level, determined by both binary and microsatellite markers, a more detailed pattern was observed. Single-step microsatellite networks of Arab and Jewish haplotypes revealed a common pool for a large portion of Y chromosomes, suggesting a relatively recent common ancestry. The two modal haplotypes in the I&P Arabs were closely related to the most frequent haplotype of Jews (the Cohen modal haplotype). However, the I&P Arab clade that includes the two Arab modal haplotypes (and makes up 32% of Arab chromosomes) is found at only very low frequency among Jews, reflecting divergence and/or admixture from other populations.     

Pure gonadal dysgenesis. Case report with unusual anatomical and endocrine findings

The syndrome of pure gonadal dysgenesis (PGD) cannot always easily be distinguished from other disorders of gonadal development. Relations are evident with Turner's syndrome, females with hypoplastic ovaries, male pseudohermaphroditism, mixed gonadal dysgenesis and the vanishing testes syndrome. The case is reported of a 40 year old female with primary amenorrhea, alopecia, eunuchoid features, XY karyotype with normal breast development and sexual hair after estrogen therapy. On laparotomy streak ovaries were found at ovarian site. Pathohistological examination revealed on the left side wolffian duct remnants such as ductuli deferentes and epididymis besides sparse Leydig-(hilus-)cells and on the right side only a rudimentary fallopian tube with subendothelial accumulation of hyperplastic Leydig-(hilus-)cells. Serum-testosterone elevation above the normal female range (630 ng/dl) persisted following gonadectomy (151 ng/dl). Ectopic Leydig-(hilus-)cells were regarded responsible for the continuing testosterone production. The present case lies on borderline between PGD and mixed gonadal dysgenesis because remnants of wolffian duct derivatives suggest unilateral fetal testicular activity; classification as PGD however was justified in purely female body features and lacking evidence of testicular tissue.     

Homozygous WNT3 mutation causes tetra-amelia in a large consanguineous family

Tetra-amelia is a rare human genetic disorder characterized by complete absence of all four limbs and other anomalies. We studied a consanguineous family with four affected fetuses displaying autosomal recessive tetra-amelia and craniofacial and urogenital defects. By homozygosity mapping, the disease locus was assigned to chromosome 17q21, with a maximum multipoint LOD score of 2.9 at markers D17S931, D17S1785, D17SS1827, and D17S1868. Further fine mapping defined a critical interval of approximately 8.9 Mb between D17S1299 and D17S797. We identified a homozygous nonsense mutation (Q83X) in the WNT3 gene in affected fetuses of the family. WNT3, a human homologue of the Drosophila wingless gene, encodes a member of the WNT family known to play key roles in embryonic development. The Q83X mutation truncates WNT3 at its amino terminus, suggesting that loss of function is the most likely cause of the disorder. Our findings contrast with the observation of early lethality in mice homozygous for null alleles of Wnt3. To our knowledge, this is the first report of a mutation in a WNT gene associated with a Mendelian disorder. The identification of a WNT3 mutation in tetra-amelia indicates that WNT3 is required at the earliest stages of human limb formation and for craniofacial and urogenital development.     

Betulaceae and Corylaceae in Trieste (NE-Italy):Aerobiological and clinical data

Airborne pollen produced by Betulaceae and Corylaceaeis present in the Trieste area for a long period fromJanuary to June, but only in April it does representa considerable proportion (436 p/m³) of the totalpollen count (1193 p/m³). In the years considered (1995–1997), there was a gradual increase in thepollen count of Corylaceae and Betulaceae: frommaximum levels of 580 p/m³ in 1995 to 1218 p/m³ in 1997, and the taxon making the mostsignificant contribution to the pollen concentrationcurve was Ostrya carpinifolia. Sensitization to Betulaceae and Corylaceae wasanalyzed in 2213 subjects visiting our clinic betweenJanuary 1st 1995 and December 31th 1997, withallergic symptoms believed to be IgE mediated. Of thegroup, 1292 (58.4%) were atopic by skin prick testand 328 of them (25.4%) were sensitized to Betulaceaeand Corylaceae. Of the 328 subjects, 72.6% werecosensitized to Gramineae, 56.1% to Oleaceae, 42.1%to Compositae, and just over half to house-dust mites(52.1%). Only ten cases were mono-sensitized (3%).Of the subjects sentitized to Betulaceae andCorylaceae, 163 complained of rhinitis (72%) and 110of asthma (33.6%), often in association withrhinitis; 177 (54%) had only seasonal symptoms.Sensitization to Betulaceae and Corylaceae is high,but its role in inducing allergic respiratorysymptoms is difficult to evaluate because almost allpatients were sensitized to other pollen types. Inconclusion, the role played by this family of trees indetermining allergic respiratory symptoms could becomeincreasingly important in this geographical area inthe future, if pollen levels continue to rise at theirpresent rates. For the moment, sensitivity toBetulaceae-Corylaceae among the population is presentalmost exclusively in subjects sensitized also toother pollen types.     

Diversity of β-Globin Mutations in Israeli Ethnic Groups Reflects Recent Historic Events

We characterized nearly 500 β-thalassemia genes from the Israeli population representing a variety of ethnic subgroups. We found 28 different mutations in the β-globin gene, including three mutations (β^S, β^C, and β^O-Arab) causing hemoglobinopathies. Marked genetic heterogeneity was observed in both the Arab (20 mutations) and Jewish (17 mutations) populations. On the other hand, two ethnic isolates—Druze and Samaritans—had a single mutation each. Fifteen of the β-thalassemia alleles are Mediterranean in type, 5 originated in Kurdistan, 2 are of Indian origin, and 2 sporadic alleles came from Europe. Only one mutant allele—nonsense codon 37—appears to be indigenous to Israel. While human habitation in Israel dates back to early prehistory, the present-day spectrum of β-globin mutations can be largely explained by migration events that occurred in the past millennium.