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M G McLaughlin

Publications and source records attributed to M G McLaughlin.

8 recordsLinked to original sources
PubMed1998

An integrated genetic linkage map of the laboratory rat.

The laboratory rat, Rattus novegicus, is a major model system for physiological and pathophysiological studies, and since 1966 more than 422,000 publications describe biological studies on the rat (NCBI/Medline). The rat is becoming an increasingly important genetic model for the study of specific diseases, as well as retaining its role as a major preclinical model system for pharmaceutical development. The initial genetic linkage map of the rat contained 432 genetic markers (Jacob et al. 1995) out of 1171 developed due to the relatively low polymorphism rate of the mapping cross used (SHR x BN) when compared to the interspecific crosses in the mouse. While the rat genome project continues to localize additional markers on the linkage map, and as of 11/97 more than 3,200 loci have been mapped. Current map construction is using two different crosses (SHRSP x BN and FHH x ACI) rather than the initial mapping cross. Consequently there is a need to provide integration among the different maps. We set out to develop an integrated map, as well as increase the number of markers on the rat genetic map. The crosses available for this analysis included the original mapping cross SHR x BN reciprocal F2 intercross (448 markers), a GH x BN intercross (205 markers), a SS/Mcw x BN intercross (235 markers), and a FHH/Eur x ACI/Hsd intercross (276 markers), which is also one of the new mapping crosses. Forty-six animals from each cross were genotyped with markers polymorphic for that cross. The maps appear to cover the vast majority of the rat genome. The availability of these additional markers should facilitate more complete whole genome scans in a greater number of strains and provide additional markers in specific genomic regions of interest.

Animals↗
PubMed1998

Independent genetic susceptibility to cardiac hypertrophy in inherited hypertension.

Cardiac hypertrophy is a common but not inevitable complication of hypertension. Variation in heart size in hypertensives may reflect independent genetic susceptibility to cardiac hypertrophy. Using an experimental genetic model, we determined the location of quantitative trait loci responsible for cardiac hypertrophy and/or hypertension. We studied 182 F2 male animals derived from a cross of the spontaneously hypertensive rat and normotensive Donryu rats. Direct mean arterial pressure (MAP) and left ventricular (LV) mass were measured at 20 weeks of age, and DNA was obtained for linkage analysis. The estimated heritability of MAP was 62% and for LV mass expressed per unit of body weight (relative LV mass) was 76%. We used 185 polymorphic markers, with an average intermarker distance of 12.3 centimorgans for a genome-wide scan in a representative subgroup of 46 animals to identify preliminary quantitative trait loci, which were then mapped in all 182 male F2 rats. Two loci showed logarithm of the odds scores of > 4.0. One on chromosome 2, Lvm-1, was linked to relative LV mass but showed no evidence of linkage to MAP. Another locus on chromosome 1, Map-1, was linked to MAP. In the same region, a locus Lvm-2 was linked with relative LV mass. These data indicate the existence of a genetic locus on chromosome 2 of the spontaneously hypertensive rat that affects relative LV mass independently of blood pressure.

Animals↗
PubMed1996

A reference cross DNA panel for zebrafish (Danio rerio) anchored with simple sequence length polymorphisms.

The ultimate informativeness of the zebrafish mutations described in this issue will rest in part on the ability to clone these genes. However, the genetic infrastructure required for the positional cloning in zebrafish is still in its infancy. Here we report a reference cross panel of DNA, consisting of 520 F2 progeny (1040 meioses) that has been anchored to a zebrafish genetic linkage map by 102 simple sequence length polymorphisms. This reference cross DNA provides: (1) a panel of DNA from the cross that was used to construct the genetic linkage map, upon which polymorphic gene(s) and genetic markers can be mapped; (2) a fine order mapping tool, with a maximum resolution of 0.1 cM; and (3) a foundation for the development of a physical map (an ordered array of clones each containing a known portion of the genome). This reference cross DNA will serve as a resource enabling investigators to relate genes or genetic markers directly to a single genetic linkage map and avoid the problem of integrating different maps with different genetic markers, as must be currently done when using randomly amplified polymorphic DNA markers, or as has occurred with human genetic linkage maps.

Alleles↗
PubMed1990

Transient acute tubular dysfunction in the newborn: CT findings.

We report the CT and sonographic findings of transient acute tubular disease in a newborn infant, who was dehydrated at birth. The initial CT scan demonstrated focal areas of increased attenuation within the central portions of both kidneys, and sonography showed echogenic medullary pyramids. After adequate hydration, a follow-up examination demonstrated complete spontaneous resolution.

Humans↗
PubMed1989

Detection of left atrial myxoma with SPECT cardiac imaging.

A 69-year-old man with a left atrial myxoma underwent a gated cardiac blood pool radionuclide study that failed to visualize the cardiac tumor on either the planar images or on the composite cineangiograms from the anterior and 45 degrees LAO projections. A nongated cardiac SPECT examination, however, easily demonstrated the atrial myxoma in its characteristic location, adjacent to the interatrial septum. SPECT dramatically improved the image contrast; provided views in transaxial, coronal, and sagittal planes; and allowed direct comparison with computed tomography. Gated cardiac SPECT may be expected to provide a more accurate analysis of the complex motion and attachment site of these intracardiac tumors, as well as a more accurate tumor volume analysis.

Aged↗
PubMed1985

Differences in the reduction kinetics of incorporated spin labels in undifferentiated and differentiated mouse neuroblastoma cells.

Significant differences in the rate of reduction of two spin labels, 5-doxylstearic acid and TEMPOL, in the undifferentiated and differentiated NB-15 mouse neuroblastoma cells were demonstrated by using electron paramagnetic resonance (EPR) spectroscopy. The half-time (T1/2) values for decay of the EPR signal of 5-doxylstearic acid in the undifferentiated and differentiated neuroblastoma cells were 70 min and 290 min, respectively. The T1/2 values of TEMPOL in the undifferentiated and differentiated cells were 18 min and 34 min, respectively. The cellular reductant was characterized as non-protein-bound sulfhydryl groups. A corresponding difference in the cellular non-protein-bound sulfhydryl content, 19.30 nmol/mg protein for the undifferentiated cells and 6.78 nmol/mg protein for the differentiated cells, was observed. Comparison of the reduction rates of TEMPOL, 5-doxylstearic acid and 16-doxylstearic acid in the undifferentiated NB-15 cells suggested that the permeation of non-protein-bound sulfhydryl compounds from the cytosol to membrane may be responsible for the reduction of the lipid-soluble stearic acid spin labels.

Animals↗
PubMedDate not supplied

Computed tomographic detection of a swallowed denture.

A 89-year-old, nursing home female presented with a two-week history of drooling and a hard palpable mass in the region of the larynx. Initial fiberoptic laryngoscopy revealed a hard pinkish-white mass which was felt to represent a tumor. Computed tomography demonstrated swallowed, impacted, complete, mandibular denture. Radiologists should be aware of this problem, particularly in the elderly demented patient.

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