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Biomedical subjects

R Hediger

Publications and source records attributed to R Hediger.

12 recordsLinked to original sources
PubMed1994

Fine-needle aspiration biopsy of pancreatic ductal adenocarcinoma: loss of diagnostic accuracy with small tumors.

Eighty-three patients underwent CT-directed fine-needle aspiration biopsies (FNAB) for pancreatic ductal adenocarcinoma. Five factors that might have influenced the diagnostic sensitivity of FNAB were analyzed: clinical history, the number of passes for each FNAB, and three radiologic criteria including tumor size, tumor location, and the presence or absence of suspected tumor necrosis by CT scan. Sixty-three patients had a diagnosis of pancreatic carcinoma confirmed by FNAB (overall sensitivity = 76%). Tumor size was the only factor that correlated with the diagnostic sensitivity of FNAB. [table: see text] Of 12 patients whose FNAB was negative but suspicious for malignancy, 10 had a repeat FNAB and 4 were positive for carcinoma. We conclude that the diagnostic sensitivity of FNAB decreases significantly with decreasing tumor size and that a repeat FNAB for suspicious biopsies should be done to increase the diagnostic yield.

Biopsy, Needle↗
PubMed1993

A balanced autosomal reciprocal translocation in an azoospermic bull.

This appears to be the first reported case of a bull with a balanced autosomal reciprocal translocation associated with azoospermia. The analysis includes somatic chromosome banding, conventional meiotic analysis, and electron microscopy of synaptonemal complexes (SCs). The karyotype of the bull was found to be 60,XY,rcp(8;13)(q11;q24). Electron microscopy of SCs in microspread pachytene spermatocytes revealed a high incidence of terminal asynapsis of the smallest arm of the quadrivalent. Most quadrivalents with such asynapsis and few with nonhomologous synapsis showed associations with the XY sex bivalent, leading to complete meiotic arrest at late pachynema. Except for one diakinetic cell, no diplotene and subsequent stages were encountered in air-dried meiotic preparations. The presence of degenerating primary spermatocytes in SC preparations, as well as in testicular sections, and the absence of spermatozoa in ejaculates confirm the chromosomally derived male sterility of the bull. X-chromosome reactivation, evidenced by the cytomorphological reversal of associated sex bivalents, appeared to be the initial step in the degeneration of spermatocytes. Consequently, the formation of a separate, fully developed XY body, which was previously demonstrated on the periphery of spermatocyte nuclei in fertile bulls, could not be attained in this case. Extensive end-to-end association of autosomal bivalents in meiotically arrested, as well as degenerating, spermatocytes was a consistent and unique observation of this study. Such associations may lead to enhanced reactivation of the X chromosome.

Animals↗
PubMed1991

Localization of the beta-subunit of follicle stimulating hormone in cattle and sheep by in situ hybridization.

The locus for the beta-subunit of the follicle stimulating hormone gene (FSHB) has been determined in both cattle and sheep by in situ hybridization of a bovine and an ovine cDNA probe, respectively, to metaphase chromosomes. Our results show that the FSHB locus is on cattle chromosome 15 in the region of bands q24-qter and in sheep on the cytogenetically homologous chromosome 15, also in the region q24-qter. The mapping of the FSHB gene in cattle together with the location of other genes (CAT, HBB and PTH) previously found to be syntenic in cattle and on human chromosome 11p, defines an evolutionarily conserved synteny. The localization of the FSHB gene to a cytogenetically homologous region in cattle and sheep is consistent with the hypothesis of extensively conserved chromosome structure in these two species.

Animals↗
PubMed1991

Chromosome banding and gene localizations support extensive conservation of chromosome structure between cattle and sheep.

By using three gene probes, one derived from the porcine major histocompatibility complex (MHC) and two from bovine cytokeratin genes, type I (KRTA) and type II (KRTB), the hypothesis of conservation of genome structure in two members of the family Bovidae was examined. Gene mapping data revealed the MHC to be in chromosome region 23q15----q23 in cattle (BOLA) and 20q15----q23 in sheep (OLA). KRTA was localized to chromosome region 19q25----q29 in cattle and 11q25----q29 in sheep and KRTB to 5q14----q22 in cattle and 3q14----q22 in sheep. The banding patterns of the chromosome arms to which the loci were assigned were identical in both species. Moreover, the resemblances of GTG- or QFQ-banding patterns between the cattle and sheep karyotypes illustrated further chromosome homologies. These studies, based on gene mapping comparisons and comparative cytogenetics, document that within bovid chromosomes, homology of banding patterns corresponds to a homologous genetic structure. Hence, we propose that gene assignments on identified chromosomal segments in one species of the Bovidae can be extrapolated, in general, to other bovid species based on the banding homologies presented here.

Animals↗
PubMed1991

Mapping of bovine cytokeratin sequences to four different sites on three chromosomes.

The chromosomal location of bovine class I and class II cytokeratin sequences was determined using in situ hybridization and Southern blot hybridization to DNA from hybrid somatic cells. The main signals were found over chromosome region 19q16----qter after in situ hybridization with two probes for the class I cytokeratin gene subfamily (KRT10 and KRT19) and over region 5q14----q23 after hybridization with probes for the class II gene subfamily (KRT1, KRT5, and KRT8). These regions most likely contain the loci of functional cytokeratin genes, with KRT10 and KRT19 mapping to 19q21 and KRT1, KRT5, and KRT8 to 5q21. The in situ hybridization data were corroborated by analysis of a somatic hybrid cell panel. The genes for the class I keratins segregated concordantly with each other and syntenic group U21 but were discordant with the class II keratin genes. The class II keratin genes segregated concordantly with each other and syntenic group U3. Two class II gene probes gave an additional minor signal above chromosome region 5q25----q33 after in situ hybridization, while another class II probe yielded a minor signal above chromosome region 10q31----qter. When the latter probe and an additional linked probe were hybridized to DNAs from a hybrid panel, two independently segregating loci were recognized, one of which cosegregated with the class II subfamily in syntenic group U3 and the other with syntenic group U5. These data confirm the chromosomal assignment of two syntenic groups and allow the assignment of a formerly unassigned syntenic group.

Animals↗
PubMed1990

Assignment of the growth hormone gene locus to 19q26-qter in cattle and to 11q25-qter in sheep by in situ hybridization.

The growth hormone gene locus (GH) of cattle and sheep was mapped to a chromosomal region in each species by using in situ hybridization. The probe employed was an 830-bp cDNA sequence from the ovine growth hormone gene. Based on QFQ chromosome preparations, our results show that the GH locus is on cattle chromosome 19 in the region of bands q26-qter and in sheep on chromosome region 11q25-qter. The GH assignments together with previous localizations of type I cytokeratin genes (KRTA) and one homeobox (HOX2) gene in cattle and one type I cytokeratin gene (KRTA) in sheep identify a strongly conserved chromosomal segment on human chromosome 17, bovine chromosome 19, and sheep chromosome 11.

Animals↗
PubMed1988

Chromosomal localization of the major histocompatibility complex of the horse (ELA) by in situ hybridization.

The first gene assignment to a horse chromosome is reported for equine leucocyte antigen (ELA), the major histocompatibility complex of the horse. A cloned DNA sequence derived from a class I gene of the porcine major histocompatibility complex was used as a probe for an in situ hybridization experiment. We present the regional localization of ELA, using this sequence, to equine chromosome 20q14-q22.

Animals↗
PubMed1988

The loci for parathyroid hormone and beta-globin are closely linked and map to chromosome 15 in cattle.

We report linkage of the loci for beta-globin (HBB) and parathyroid hormone (PTH) in cattle and the assignment of both loci to the bovine chromosome region 15q13-q23. Linkage was analyzed in a family of paternal half-sibs by the use of restriction fragment length polymorphisms detected with bovine probes derived from the HBB and PTH genes. The HBB polymorphism was detected by digestion with restriction endonuclease HindIII and the PTH polymorphism with MspI. The maximum lod score for linkage of PTH with HBB was zeta = 4.52 at theta = 0, suggesting very close linkage of the two loci. The finding of the PTH/HBB linkage is corroborated by the physical assignment of both loci to the region 15q13-q23 by in situ hybridization with bovine genomic probes derived from PTH and HBB, respectively. Since HBB and PTH are syntenic in man and mouse, these results in cattle represent another example of conservation of synteny in the evolution of mammalian chromosomes.

Alleles↗
PubMed1988

[Hypotrichosis and oligodontia, combined with an Xq-deletion, in a calf of the Swiss Holstein breed].

Hypotrichosis and oligodontia associated with a chromosomal anomaly (Xq-deletion) are described in a 11-month old cattle (Simmenthal/Red Holstein cross-breed). This chromosomal anomaly was accompanied with hairlessness and grievous teeth abnormalities. The animal had a very thin haircoat, had only one incisor and between one to three molars per mandible or maxilla. This resulted in reduced food intake, reduced rumination, and retarded growth. Post-mortem examination revealed lesions in the kidneys (bilateral chronic interstitial nephritis), adrenals (hyperplasia), pancreas (focal fibrosis) and abomasum (obstipation and multiple ulcers). Some of these abnormalities are comparable with the human "anhidrotic ectodermal dysplasia" (Christ-Siemens-Touraine syndrome) and supports the hypothesis that there are homologies in the X-chromosome of different mammals.

Abnormalities, Multiple↗
PubMedDate not supplied

Recurrent chondrosarcoma of the hyoid bone.

Chondrosarcoma is a malignant tumor of cartilaginous origin, and the second most common primary malignant bone tumor in the United States. Only approximately 10% of chondrosarcomas occur in the head and neck region, and of these the hyoid bone is a rare site of involvement. This report describes such a case, as well as the radiographic features as seen by CT scan.

Aged↗