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M R Wallace

Publications and source records attributed to M R Wallace.

At least 163 records · Page 9Linked to original sources
PubMed1990

A chromosome jump crosses a translocation breakpoint in the von Recklinghausen neurofibromatosis region.

The von Recklinghausen neurofibromatosis (NFI) gene has been previously localized to the region 17q11.2 by genetic analysis. Consistent with this, two NFI patients have been described with autosomal translocations with breakpoints in 17q11.2, and these represent presumed markers for the location of the NFI gene. Recent work has defined the two breakpoints on a physical map, and they lie less than 100 kb apart. To characterize further the distance between these breakpoints and clone additional DNA, a chromosome jump was made from a DNA fragment that maps between the breakpoints. The end of the jump crosses one of the NFI translocation breakpoints and detects that breakpoint on Southern analysis, placing the probe less than 15 kb telomeric to this breakpoint. Pulsed field analysis with the jump clone allows revision of the previous NFI region map and indicates that the two breakpoints lie no more than 60 kb apart. This jump clone will be useful for further mapping, breakpoint cloning, analysis of patient DNA, and the search for transcripts in the NFI region.

Cell Line↗
PubMed1990

Familial amyloid polyneuropathy: alanine-for-threonine substitution in the transthyretin (prealbumin) molecule.

A previously reported family with amyloid polyneuropathy (FAP) was reinvestigated to determine the type of mutation in the transthyretin (prealbumin) molecule. Transthyretin was isolated from amyloid-laden myocardium and serum, and tryptic peptides were resolved by high-performance liquid chromatography. Amino acid sequencing of an anomalous peptide revealed an alanine-for-threonine substitution corresponding to position No. 60 of the transthyretin monomer. Detection of the FAP gene in asymptomatic carriers was accomplished by hybrid isoelectric focusing of transthyretin in the presence of dithiothreitol and high concentrations of urea, and by Southern blotting of Pvull-digested leukocyte deoxyribonucleic acid. This type of FAP was found to be identical to the previously described Appalachian amyloid. Patients with FAP and their asymptomatic gene-carrying offspring had significantly reduced levels of serum transthyretin and retinol-binding protein.

Adult↗
PubMed1990

Localization of a human T-cell-specific gene, RANTES (D17S136E), to chromosome 17q11.2-q12.

We report here the localization of the gene for a human T-cell-specific molecule, designated RANTES, to human chromosome region 17q11.2-q12 by in situ hybridization and analysis of somatic cell hybrids using a cDNA probe to the gene. We have recently shown that this gene, which encodes a small, secreted, putative lymphokine, is a member of a larger gene family some of whose members reside on chromosome 4 but most of whose members have not to date been mapped. A secondary hybridization peak was noted on the region of human chromosome 5q31-q34, which may represent the location of other members of the gene family. Interestingly, this latter region overlaps with the location of an extended linked cluster of growth factor and receptor genes, some of which may be coregulated with members of the RANTES gene family.

Amino Acid Sequence↗
PubMed1990

Human chromosome 17 NotI linking clones and their use in long-range restriction mapping of the Miller-Dieker chromosome region (MDCR) in 17p13.3.

A NotI linking library constructed from flow-sorted human chromosome 17 material was screened to aid in construction of a long-range restriction map of the Miller-Dieker chromosome region (MDCR) in 17p13.3. A total of 66 clones were mapped to one of eight regions of chromosome 17 using a somatic cell hybrid panel, and 44/66 (67%) of these clones cross-hybridized to rodent DNA on Southern blots. Of these, 24 clones were tested and all mapped to mouse chromosome 11, the homolog of human chromosome 17. Four linking clones mapped to 17p13.3 and were used for pulsed-field gel electrophoresis studies along with six other anonymous probes previously mapped to this region. Clone L132 was found to be deleted in all Miller-Dieker patients tested (n = 15) and therefore lies within the critical region for this disorder. It detects two NotI fragments (180 and 320 kb), one of which (320 kb) was shared by YNZ22 and YNH37, two probes previously shown to be co-deleted in all patients with the Miller-Dieker syndrome (MDS). These results indicate that all MDS patients share a minimum deletion region of greater than 370 kb. Two other NotI clones, L53 and L125, mapped telomeric to the MDS critical region and share a 600-kb MluI fragment with each other and with YNZ22/YNH37. This provides a 930-kb MluI map that encompasses the distal boundary of the MDS critical region but does not include the proximal boundary. A total of over 2 Mbp is represented in the MluI fragments by probes in subband p13.3, a cytogenetic region estimated to be 3-4 Mbp.

Abnormalities, Multiple↗
PubMed1990

A 90 kb DNA deletion associated with neurofibromatosis type 1.

A deletion of 90 kb of DNA has been identified in a patient with neurofibromatosis type 1, using pulsed field gel electrophoresis. The deletion lies between probes 17L1A and AC5 in the critical region of chromosome 17 and represents the only molecular alteration found by PFGE in a series of 90 unrelated patients. The subject showing the deletion is an isolated case, shows typical clinical features, and represents one of the first examples of a molecular deletion to be found in this disorder.

Chromosome Deletion↗
PubMed1990

Role of renal interstitial hydrostatic pressure in the blunted natriuretic response to saline loading in the piglet.

Acute saline volume expansion (VE) in the developing animal is associated with a blunted natriuretic response when compared with that in adults. Recent studies have suggested that renal interstitial hydrostatic pressure (RIHP) plays an important role in mediating VE-induced natriuresis in the adult. The purpose of our study was to determine whether abnormalities in the RIHP response to VE could be involved in the blunted natriuretic response in the developing animal. The effect of an acute saline load (5% body wt) on RIHP and sodium excretion was examined in adult pigs (greater than 70 d) and piglets (26-43 d). In response to an acute saline load, the piglets excreted significantly less sodium than the adults (1.7 +/- 0.5 versus 3.8 +/- 0.7 mumol/min/g kidney wt). The increase in fractional excretion of sodium in response to VE was also significantly less in the piglets. There was no significant change in GFR in either group. Associated with the blunted natriuretic response in the piglet was an absence of an increase in RIHP (6.1 +/- 1.1 versus 6.1 +/- 1.6 mm Hg) in response to VE. In contrast, the adult pig, which exhibited a normal natriuretic response, showed a significant increase in RIHP (8.8 +/- 1.3 to 12.3 +/- 1.5 mm Hg) during VE. When RIHP was prevented from increasing during VE in the adult pigs, the natriuretic response was significantly attenuated, as it was in the piglets.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1990

Moraxella (Branhamella) catarrhalis bacteremia. A case report and literature review.

Moraxella catarrhalis is increasingly recognized as a cause of pulmonary and upper airway disease, but bacteremia remains unusual. We treated a 71-year-old man who died of rapidly progressive bacteremic M catarrhalis bronchopneumonia. This case, and a review of the 27 previously reported M catarrhalis bacteremias in the literature, demonstrated that M catarrhalis can be a virulent organism capable of causing serious infection and death in both immunocompetent and compromised hosts.

Aged↗
PubMed1989

The return of acute rheumatic fever in young adults.

The incidence of acute rheumatic fever (ARF) in the United States has been steadily declining for three decades, and by the mid-1980s had virtually disappeared. In the past 3 years, however, several scattered outbreaks have occurred among US schoolchildren, and there is speculation that ARF will again become a major public health problem in North America. We report a clustering of 10 cases of ARF in young men undergoing basic training at a recruit camp in San Diego, Calif. This was the first such outbreak in two decades among US military personnel and the largest reported series of ARF cases among adults in more than a decade in the United States. Adult-onset ARF was not benign in our patients. The rate of carditis (3 of 10 patients) was similar to that in older studies of adults with ARF. All patients in our series suffered severe polyarthritis, anemia, and fever, but only 60% gave any history of preceding pharyngitis. Rheumatic fever must again be suspected in adults, as well as children, who present with polyarthritis.

Acute Disease↗
PubMed1989

Physical mapping of a translocation breakpoint in neurofibromatosis.

The gene for von Recklinghausen neurofibromatosis (NF1), one of the most common autosomal-dominant disorders of humans, was recently mapped to chromosome 17 by linkage analysis. The identification of two NF1 patients with balanced translocations that involved chromosome 17q11.2 suggests that the disease can arise by gross rearrangement of the NF1 locus, and that the NF1 gene might be identified by cloning the region around these translocation breakpoints. To further define the region of these translocations, a series of chromosome 17 Not I-linking clones has been mapped to proximal 17q and studied by pulsed-field gel electrophoresis. One clone, 17L1 (D17S133), clearly identifies the breakpoint in an NF1 patient with a t(1;17) translocation. A 2.3-megabase pulsed-field map of this region was constructed and indicates that the NF1 breakpoint is only 10 to 240 kilobases away from 17L1. This finding prepares the way for the cloning of NF1.

Chromosome Mapping↗
PubMed1989

Direct construction of a chromosome-specific NotI linking library from flow-sorted chromosomes.

A linking library consists of genomic DNA fragments which contain a specific rare restriction enzyme site; such clones are very useful as probes in pulsed field gel electrophoresis and in mapping and cloning large regions of DNA. However, identifying those linking clones which map to a certain chromosomal region can be laborious. Therefore, we have developed a straightforward procedure for constructing a linking library directly from flow-sorted chromosomes. As a test of the approach, a NotI linking library was constructed from the chromosome 17 fraction of a flow-sort of human chromosomes, using only 70 ng of DNA. Thirteen of sixteen linking clones were mapped to chromosome 17, suggesting that the library is highly enriched for this chromosome. This method should be generally applicable to other chromosomes and enzymes as well.

Chromosome Mapping↗
PubMed1989

Molecular dissection of a contiguous gene syndrome: frequent submicroscopic deletions, evolutionarily conserved sequences, and a hypomethylated "island" in the Miller-Dieker chromosome region.

The Miller-Dieker syndrome (MDS), composed of characteristic facial abnormalities and a severe neuronal migration disorder affecting the cerebral cortex, is caused by visible or submicroscopic deletions of chromosome band 17p13. Twelve anonymous DNA markers were tested against a panel of somatic cell hybrids containing 17p deletions from seven MDS patients. All patients, including three with normal karyotypes, are deleted for a variable set of 5-12 markers. Two highly polymorphic VNTR (variable number of tandem repeats) probes, YNZ22 and YNH37, are codeleted in all patients tested and make molecular diagnosis for this disorder feasible. By pulsed-field gel electrophoresis, YNZ22 and YNH37 were shown to be within 30 kilobases (kb) of each other. Cosmid clones containing both VNTR sequences were identified, and restriction mapping showed them to be less than 15 kb apart. Three overlapping cosmids spanning greater than 100 kb were completely deleted in all patients, providing a minimum estimate of the size of the MDS critical region. A hypomethylated island and evolutionarily conserved sequences were identified within this 100-kb region, indications of the presence of one or more expressed sequences potentially involved in the pathophysiology of this disorder. The conserved sequences were mapped to mouse chromosome 11 by using mouse-rat somatic cell hybrids, extending the remarkable homology between human chromosome 17 and mouse chromosome 11 by 30 centimorgans, into the 17p telomere region.

Biological Evolution↗
PubMed1989

Physical mapping of the von Recklinghausen neurofibromatosis region on chromosome 17.

The von Recklinghausen neurofibromatosis (NF1) locus has been linked to chromosome 17, and recent linkage analyses place the gene on the proximal long arm. NF1 probably resides in 17q11.2, since two unrelated NF1 patients have been identified who possess constitutional reciprocal translocations involving 17q11.2 with chromosomes 1 and 22. We have used a somatic-cell hybrid from the t(17;22) individual, along with other hybrid cell lines, to order probes around the NF1 locus. An additional probe, 17L1, has been isolated from a NotI linking library made from flow-sorted chromosome 17 material and has been mapped to a region immediately proximal to the translocation breakpoint. While neither NF1 translocation breakpoint has yet been identified by pulse-field gel analysis, an overlap between two probes, EW206 and EW207, has been detected. Furthermore, we have identified the breakpoint in a non-NF1 translocation, SP-3, on the proximal side of the NF1 locus. This breakpoint has been helpful in creating a 1,000-kb pulsed-field map, which includes the closely linked NF1 probes HHH202 and TH17.19. The combined somatic-cell hybrid and pulsed-field gel analysis we report here favors the probe order D17Z1-HHH202-TH17.19-CRYB1-17L1-NF1- (EW206, EW207, EW203, L581, L946)-(ERBB2, ERBA1). The agreement in probe ordering between linkage analysis and physical mapping is excellent, and the availability of translocation breakpoints in NF1 should now greatly assist the cloning of this locus.

Animals↗
PubMed1989

Genetic amyloidosis: recent advances.

The hereditary amyloidoses are usually associated with peripheral neuropathy and, for this reason, they have been called familial amyloidotic polyneuropathy (FAP). The neuropathy usually involves both the peripheral sensory motor and autonomic nervous systems, resulting in not only loss of sensation and motor function but also bowel dysfunction and orthostatic hypotension. In addition, most of the FAP syndromes involve other organ systems, in particular the renal and cardiac systems. Renal amyloidosis usually presents as nephrotic syndrome and later terminates in azotemia. Cardiac amyloidosis may present as congestive heart failure or arrhythmia. Whereas the neuropathy of hereditary amyloidosis may be the most prominent clinical feature, it is renal or cardiac disease that often dictates the length of survival.

Alanine↗
PubMed1989

Refined physical and genetic mapping of the NF1 region on chromosome 17.

A total of 15 polymorphic markers were used to construct a genetic map that encompasses the NF1 locus on chromosome 17. The markers were a subset of a large collection of chromosome 17-specific probes and were selected for marker typing in NF1 families after physical localization to the pericentric region of the chromosome. Multilocus data for a total of 17 informative NF1 families and 39 other families were included in genetic analyses. No recombination was observed between NF1 and four markers, one or more of which was informative in 86% of parents. More-refined physical mapping studies demonstrated that all four of the markers are proximal to the chromosome 17 translocation breakpoints from two NF1 patients bearing balanced translocations. The region flanking the disease locus spans a distance of 1 centimorgan (cM) in males and 9 cM in females. Close flanking markers were informative in 76% of meioses. Sex differences in recombination rates in the pericentric region were highly significant statistically.

Chromosomes, Human, Pair 17↗
PubMed1988

Measurement of plasma oxalate by capillary gas chromatography and its validation by isotope dilution mass spectrometry.

A capillary gas chromatographic method for plasma oxalate and an isotope dilution mass spectrometric reference method, both using the same tert.-butyldimethylsilyl derivatives, are described. Similar reference ranges for both were found (4.93 +/- 1.48 and 4.70 +/- 1.44 mumol/l, respectively), together with a close correlation for results covering a wide range of oxalate concentrations.

Carbon Radioisotopes↗
PubMed1988

Genetic linkage map of human chromosome 21.

Two of the most common disorders affecting the human nervous system, Down syndrome and Alzheimer's disease, involve genes residing on human chromosome 21. A genetic linkage map of human chromosome 21 has been constructed using 13 anonymous DNA markers and cDNAs encoding the genes for superoxide dismutase 1 (SOD1) and the precursor of Alzheimer's amyloid beta peptide (APP). Segregation of restriction fragment length polymorphisms (RFLPs) for these genes and DNA markers was traced in a large Venezuelan kindred established as a "reference" pedigree for human linkage analysis. The 15 loci form a single linkage group spanning 81 cM on the long arm of chromosome 21, with a markedly increased frequency of recombination occurring toward the telomere. Consequently, 40% of the genetic length of the long arm corresponds to less than 10% of its cytogenetic length, represented by the terminal half of 21q22.3. Females displayed greater recombination than males throughout the linkage group, with the difference being most striking for markers just below the centromere. Definition of the linkage relationships for these chromosome 21 markers will help refine the map position of the familial Alzheimer's disease gene and facilitate investigation of the role of recombination in nondisjunction associated with Down syndrome.

Chromosome Mapping↗