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L M Silverman

Publications and source records attributed to L M Silverman.

At least 37 records · Page 2Linked to original sources
PubMed1994

Association of pancreatic adenocarcinoma, mild lung disease, and delta F508 mutation in a cystic fibrosis patient.

A case of adenocarcinoma of the pancreas and mild lung disease in a 39-year-old man homozygous for the delta F508 cystic fibrosis mutation is presented. Cystic fibrosis is the most common lethal genetic disease in Caucasians, and is most commonly associated with severe obstructive lung disease. To our knowledge, this is only the fifth case of adenocarcinoma of the pancreas in a CF patient to be reported and the first case for which molecular data are available. The rare incidence of this type of malignancy in the general population suggests a possible association of CF with this malignant disease.

Adenocarcinoma↗
PubMed1994

Localized in situ amplification (LISA): a novel approach to in situ PCR.

Amplification of specific gene target sequences has become a routine molecular procedure in a variety of laboratories. When coupled with either a direct or indirect method of detecting amplified product, in situ amplification offers an extremely powerful investigative tool. We describe a protocol for a localized in situ amplification (LISA) reaction that includes tissue-culture cloning rings and allows for the amplification of gene target sequences in specific regions of paraffin-embedded tissue sections. Digoxigenin-11-dUTP was added to the amplification reaction and thus incorporated into the amplified products, providing a mechanism by which direct nonisotopic detection could be performed. To demonstrate the approach, LISA was performed on known positive Pneumocystis carinii rat lung tissues, with primers specific for the P. carinii rRNA gene sequence.

Animals↗
PubMed1993

Molecular pathology of the fragile X syndrome.

Fragile X syndrome is the most common form of familial mental retardation (one in 1250 males and one in 2500 females, characterized by prominent dysmorphic features, macro-orchidism, and varying degrees of mental retardation. Diagnosis of this syndrome has relied on cytogenetic demonstration of the fragile site at position Xq27.3. A gene associated with the fragile X syndrome, FMR-1, has been isolated and mapped to the region of the X chromosome that corresponds to the region of the fragile site. Expansion of a trinucleotide repeat, CGG, and abnormal methylation of a CpG island account for the majority of mutations identified in FMR-1. These molecular characteristics have greatly enhanced the identification of affected individuals and carriers of the premutation who were not detected cytogenetically.

Blotting, Southern↗
PubMed1992

Complete deletion of the androgen receptor gene: definition of the null phenotype of the androgen insensitivity syndrome and determination of carrier status.

The molecular basis of androgen insensitivity was investigated in a family with the complete form of the syndrome. Polymerase chain reaction amplification and Southern blot analysis of genomic DNA revealed a deletion of the entire androgen receptor (AR) gene in affected individuals. The carrier status of female members of this family was examined using a HindIII restriction fragment length polymorphism associated with the AR gene. Obligate carriers were hemizygous for one of the two alleles at this locus, while heterozygosity for the polymorphic alleles, implying the presence of two copies of the AR gene, indicated noncarrier status. This conclusion was supported by gene dosage studies using comparative densitometric analysis of Southern blots hybridized simultaneously with an AR cDNA probe and a control cDNA probe from an unrelated gene. Finally, the pattern of inheritance of another X-linked DNA polymorphism allowed us to conclude that the original mutation had occurred in the germ line of the maternal great-grandfather of the index patient. Although rare, complete deletion of the AR gene is of particular importance in terms of correlation between molecular defect and phenotype, as it represents the quintessential form of complete androgen insensitivity, the null phenotype.

Alleles↗
PubMed1991

Detecting multiple cystic fibrosis mutations by polymerase chain reaction-mediated site-directed mutagenesis.

The polymerase chain reaction (PCR) has been applied in a novel manner to detect the multiple mutations causing cystic fibrosis (CF). PCR-mediated site-directed mutagenesis (PSM) has been applied to create allele-specific restriction enzyme cutting sites for three of the more common mutations. Two other mutations after cutting sites on their own. We discuss the implications for the expedient detection of five different CF-causing mutations.

Base Sequence↗
PubMed1990

Molecular probe protocol for determining carrier status in Duchenne and Becker muscular dystrophies.

By use of cDNA probes, molecular deletions were identified in 66.6% of 42 patients with Duchenne muscular dystrophy (DMD) or Becker muscular dystrophy (BMD). Owing to this high deletion rate, a new strategy for detecting DMD/BMD carriers is feasible in which the polymerase chain reaction is used as an initial screen for detecting the deletions occurring in specific deletion-prone exons. Because the deletions do not occur randomly, specific cDNA probes are utilized first with Southern blot analysis. Identification of a deletion permits direct analysis for DMD carrier status and removes the inherent limitations of the conventional restriction fragment length polymorphism technique. Carrier status is determined by scanning the autoradiographs with a densitometric spectrophotometer or by detection of a junction fragment.

Bacterial Proteins↗
PubMed1990

Frequency of the delta Phe508 mutation and correlation with XV.2c/KM-19 haplotypes in an American population of cystic fibrosis patients: results of a collaborative study.

The cystic fibrosis (CF) gene has been recently cloned, and a deletion of 3 basepairs (bp) of DNA was found on most of the CF chromosomes. This deletion leads to the synthesis of a protein that lacks a phenylalanine residue at position 508. Using two polymerase chain reaction protocols to study the frequency of this mutation in a series of 192 CF patients, we found the mutation on 72% of affected chromosomes. We then used this value to calculate the predictive value of a negative test result in a population-based screening program for CF carrier status. Haplotype analysis with the polymorphic markers XV.2c and KM-19 on 239 CF chromosomes revealed that 90.7% of CF chromosomes with the deletion had a single haplotype. This haplotype was also associated with 60.4% of CF chromosomes with unknown mutations. These values can be used to calculate the probability of whether an individual from the general population is a carrier of any CF mutation.

Base Sequence↗
PubMed1990

A model for molecular screening of newborns: simultaneous detection of Duchenne/Becker muscular dystrophies and cystic fibrosis.

Gene mutations responsible for the majority of Duchenne/Becker muscular dystrophy (DMD/BMD) and cystic fibrosis (CF) chromosomes have been identified. We describe a DNA-based strategy, rather than the traditional biochemical assays, for screening newborns. DNA sequences spanning the CF mutation and several DMD/BMD deletion-prone exons are amplified simultaneously via a multiplex polymerase chain reaction. The gel is visually inspected for DMD/BMD deletions and then blotted and hybridized with allele-specific oligonucleotides to determine the presence or absence of the CF mutation. We determined that blood spots provide sufficient DNA for the molecular analysis, so the procedure can be used in screening programs of newborns.

Base Sequence↗
PubMed1990

Determination of carrier status in Duchenne and Becker muscular dystrophies by quantitative polymerase chain reaction and allele-specific oligonucleotides.

Detection of carriers of Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD), in the deletion cases, involves calculating gene dosage from Southern blots. We show that the analysis of dosage can also be made from the polymerase chain reaction (PCR) with use of allele-specific oligonucleotides (ASOs). The deletion-prone exons are amplified, transferred to a membrane, and hybridized with ASOs complementary to the exons; the autoradiographic bands are then quantified with a densitometer. After determining the quantitative conditions of the amplification reaction, we were able to identify deletions in a DMD/BMD carrier female. The determination of carrier status via PCR removes several of the technical limitations of Southern analysis and is also cost- and labor-effective.

Alleles↗
PubMed1990

Relative increase in creatine kinase MB isoenzyme during reperfusion after myocardial infarction is method dependent.

We compared relative increases in creatine kinase (EC 2.7.3.2) MB isoenzyme (CK-MB) after reperfusion in myocardial infarction for four popular methods: electrophoresis, immunoinhibition, the "Magic Lite" (Ciba-Corning) system, and the Stratus (Dade). In a method comparison study, we confirmed that all four methods correlated (r greater than 0.95). Electrophoresis demonstrated the greatest scatter about the regression line, immunoinhibition the least. For CK-MB quantities near each method's "positive cutoff" indicating myocardial infarction, results by all methods agreed in 95% of samples. To characterize relative increases in CK-MB, we computer-fitted data obtained from each method for serial specimens collected from six acute myocardial infarction patients during myocardial reperfusion. Although for each individual patient the four methods appeared to exhibit parallelism, the methods differed significantly in terms describing their appearance rate, peak-time & fall-off, and time-to-peak activity. Consistent with these data, we found that the relative CK-MB increases at various times after reperfusion, compared with baseline concentrations, are method-dependent. Therefore, when using CK-MB for indicating coronary patency, one must develop specific limits for each method utilized.

Adult↗
PubMed1989

Biochemical effects of 17 beta-estradiol on UMR106 cells.

The effect of 17 beta-estradiol (E) on an osteoblast-like cell line, UMR106, was studied in vitro. The concentrations of transferrin and seven enzymes (gamma glutamyl transferase, alkaline phosphatase, acid phosphatase, lactate dehydrogenase, creatine kinase, alanine aminotransferase and aspartate aminotransferase) were measured in these cells after incubation in culture medium containing either E or the vehicle. E treatment increased five of the seven enzymes and increased the transferrin concentration in the UMR106 cells while simultaneously reducing the proliferation rates. 4-Hydroxytamoxifen, an estrogen antagonist, produced a mild estrogen agonist action on growth rates and enzyme concentrations in the UMR106 cells. When E was present simultaneously, the agonist properties of 4-hydroxytamoxifen were enhanced. These studies show that E enhanced activity of five enzymes and the transferrin content of UMR106 cells after a 2-day incubation. 4-Hydroxytamoxifen enhanced the E effect, illustrating that estrogen antagonists may manifest agonist or antagonist properties depending on the model. These results extend our previous observations showing a direct effect of E in vitro on osteoblast-like cells.

Acid Phosphatase↗
PubMed1989

Immunochemical assays for IgG, IgA, IgM and transferrin compared.

We compared immunochemical methods for determining IgG, IgA, IgM, and transferrin in serum by studying calibrator crossover, patient comparison, and, for a newly developed technology, normal reference intervals. For the immunoglobulins, we compared radial immunodiffusion (RID), rate nephelometry using the Beckman ICS, and a new nephelometric method adapted to the Abbott TDx; for transferrin we compared the ICS, TDx, and immunoturbiditry. The methods examined for quantifying IgA and transferrin showed good agreement in calibrator crossover and patient comparison studies. In studies comparing IgG methods, the ICS and TDx demonstrated acceptable agreement, although neither showed accordance with RID. For IgM determination, crossover studies and patients having less than 4300 mg/L in this protein showed good agreement, even though more elevated samples, run on the TDx, showed a discrepancy in proportionally compared to the other two methods. Normal reference intervals (95% confidence limits) determined on the TDx agreed well with those established for the other immunochemical methods.

Adolescent↗