Large Heterologies Impose Their Gene Conversion Pattern onto Closely Linked Point Mutations.

We have studied the meiotic non-Mendelian segregation (NMS) pattern of seven large heterologous combinations located in the b2 ascospore gene of Ascobolus. The NMS patterns of these aberration heterozygotes widely differ from each other and from those of point mutations located in the same genetic region. They give lower gene conversion frequencies than point mutations, no postmeiotic segregations (PMS), and either parity or disparity that favors the wild type allele.

Premeiotic and Meiotic Instability Generates Numerous b2 Mutation Derivatives in Ascobolus.

We have studied the genetic characteristics of an unstable mutation located in the central region of the b2 gene of the fungus Ascobolus. In crosses to wild type, this spontaneous white ascospore mutation (G0 ) gives rise to a stable white spored derivative (G1) at a frequency of 5 x 10(-3). G1 is a frameshift mutation and differs from G0 by its gene conversion pattern.

[Unusual aspects of the late manifestations of diaphragmatic hernia].

A 5-year-old boy investigated for abnormality in right cardiophrenic angle was found on radiologic and perioperative exploration to have a large diaphragmatic hernia allowing right intrathoracic passage of stomach and colon. The diaphragmatic defect included a wide left middle diaphragmatic Bochdalek cleft adherent to hiatal orifice due to agenesis of pillars.

Two mechanisms for directional gene conversion.

G234 is a large silent deletion located in the middle of gene b2, which controls spore pigmentation in Ascobolus immersus. Its gene conversion directionality was studied in asci, which show evidence of heteroduplex DNA at flanking markers, and was compared to the behavior of closely linked single-base-pair insertions or deletions. We found that with the G234 deletion, the genotype of the donor strand in the heteroduplex is preferentially recovered, irrespective of its G234 or wild-type nature, whereas with single-base-pair insertions or deletions, the direction of conversion favors one genotype, whether it was the donor or the recipient strand.

[Angiodysplasia of the colon. Apropos of a case].

A case of angiodysplasia of the right colon is reported. Clinical, radiological, endoscopic and pathological aspects are described. Beside the arteriography, the authors insist on the special usefulness of the coloscopy which helps the diagnosis and gives therapeutic possibilities as well by electrocoagulation of the lesion.

Hybrid DNA formation during meiotic recombination.

G234 is a silent mutation located in the middle of gene b2, which controls spore pigmentation in Ascobolus immersus. Its effect on the aberrant segregation patterns of while spore mutants located in the same gene was investigated. When heterozygous, G234 decreases the frequency of aberrant segregations of the mutants located on its right, toward the low conversion end.

[Glomerulosclerosis: myeloma or diabetes? (author's transl)].

A 52 year old man was admitted to hospital for persistent back pain, fixed proteinuria of 6g/24 h that lead to the nephrotic syndrome (proteids 40 g/l, albumin 21,2 g/l). Two possible etiologies were envisaged: 1) Myeloma with K light chains as evidenced by biological findings (absence of normal Ig, presence of K light chains both in blood and urine, malignant medullary plasmocytosis) as well as x-rays (small punched out lesions). 2.