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G Ramon

Publications and source records attributed to G Ramon.

4 recordsLinked to original sources

Evidence for individual and between-family variability of the recombination rate in cattle.

We have conducted a study based on single sperm typing in a family design to assess patterns of variability of the male recombination rate in cattle. 2214 sperm of 37 bulls were typed for 11 loci on bovine Chromosomes (Chrs) 6, 23, and the sex chromosomes. Statistically significant individual variability of the recombination rate was observed for one interval in the pseudoautosomal region (PAR) of the bovine sex chromosomes; one marker interval on bovine Chr 23 exhibited individual variability that was close to significance. Thirty-five of the bulls were members of six paternal halfsib groups, and highly significant variability between families was found for one interval in the PAR. This variability may be due to DNA sequence differences in the PAR or to a genetic control of the recombination activity in this region. It is demonstrated that differences in the recombination rate of the magnitude observed in the present study may have a considerable impact on the power of QTL mapping experiments as well as on the sustainability of marker-assisted selection strategies.

Animals↗

Glomerulosclerosis in obstructive uropathy.

Obstructive uropathy is said to result in populations of remnant nephrons subject to hyperfiltration. We studied all obstructed renal tissue removed at our pediatric institution during a 10-year period for focal segmental glomerulosclerosis, which is the histological hallmark of hyperfiltration. Over-all, the histological specimens from 20 patients with ureteropelvic junction obstruction, 14 who underwent heminephrectomy for duplication anomalies and 5 with posterior urethral valves who underwent native nephrectomy were studied. Focal segmental glomerulosclerosis was one of the most common histological findings in these obstructed kidneys but it almost always was found in association with intense interstitial and periglomerular inflammation. We conclude that although focal segmental glomerulosclerosis is common in obstructive uropathological conditions it results from the inflammatory response within the renal parenchyma and not from the hyperfiltration of remnant nephron populations.

Child↗