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J C Murray

Publications and source records attributed to J C Murray.

At least 145 records · Page 8Linked to original sources
PubMed1994

Isolated bone relapse during hematologic remission in childhood acute lymphoblastic leukemia: report of a metatarsal relapse and review of the literature.

An 11-year-old boy with prior bone marrow and testicular relapses of his acute lymphoblastic leukemia (ALL) developed an isolated metatarsal bone relapse during complete hematologic remission 10 months after completion of chemotherapy. Although there was no radiographic or histologic evidence of additional occult leukemia, the polymerase chain reaction (PCR) technique detected a leukemic clone in both his bone marrow and metatarsal. A literature survey revealed only 10 reported cases of isolated bone relapse occurring during complete bone marrow remission in childhood ALL. Most of these patients had prior bone marrow or extramedullary relapses. The majority experienced subsequent relapses after their isolated bone recurrence. We report a case of isolated bone recurrence, review all previously reported cases, and suggest that PCR elucidation of clonal disease may provide a better understanding of these extremely rare extramedullary events.

Humans↗
PubMed1994

The DNA rearrangement associated with facioscapulohumeral muscular dystrophy involves a heterochromatin-associated repetitive element: implications for a role of chromatin structure in the pathogenesis of the disease.

Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant form of muscular dystrophy. The FSHD locus has been linked to the most distal genetic markers on the long arm of chromosome 4. Recently, a probe was identified that detects an EcoRI fragment length polymorphism which segregates with the disease in most FSHD families. Within the EcoRI fragment lies a tandem array of 3.2 kb repeats. In several familial cases and four independent sporadic FSHD mutations, the variation in size of the EcoRI fragment was due to a decrease in copy number of the 3.2 kb repeats. To gain further insight into the relationship between the tandem array and FSHD, a single 3.2 kb repeat unit was characterized. Fluorescence in situ hybridization (FISH) demonstrates that the 3.2 kb repeat cross-hybridizes to several regions of heterochromatin in the human genome. In addition, DNA sequence analysis of the repeat reveals a region which is highly homologous to a previously identified family of heterochromatic repeats, LSau. FISH on interphase chromosomes demonstrates that the tandem array of 3.2 kb repeats lies within 215 kb of the 4q telomere. Together, these results suggest that the tandem array of 3.2 kb repeats, tightly linked to the FSHD locus, is contained in heterochromatin adjacent to the telomere. In addition, they are consistent with the hypothesis that the gene responsible for FSHD may be subjected to position effect variegation because of its proximity to telomeric heterochromatin.

Base Sequence↗
PubMed1994

Keloids treated with excision followed by radiation therapy.

BACKGROUND: In the treatment of keloids surgical excision followed by radiation therapy provides the highest reported control rates of 72% to 92%. OBJECTIVE: We evaluated the effectiveness of excision followed by radiation therapy in the treatment of keloids and compared the efficacy of orthovoltage and electron beam radiation. METHODS: One hundred twenty-six keloids were treated with radiation therapy after surgical excision. Median follow-up period was 12 years. Recurrence rate, side effects, and effectiveness of therapy were assessed. Data were analyzed with multivariate analysis for significant objective and subjective factors. RESULTS: Higher posttreatment recurrence rates were noted with keloids forming at infected sites and in patients with a family history. No increased likelihood of recurrence was noted with respect to patient age, sex, or ethnicity; keloid size or location; individual keloid history; or prior therapy or radiation type used. CONCLUSION: Excision followed by radiation therapy is a useful and effective method of keloid eradication, particularly in cases in which lesions are disfiguring or refractory. Electron beam radiation offers no advantage over orthovoltage as a treatment.

Adolescent↗
PubMed1994

Integrated human genome-wide maps constructed using the CEPH reference panel.

High resolution linkage maps have proven to be invaluable tools in genetic investigations. We have assembled a collection of genetic maps constructed from primary data collected from investigators performing genotyping using the Centre Etude Polymorphism Humain (CEPH) reference pedigree panel. These maps were constructed using a rigorous, semi-automated map construction algorithm that evaluates the integrity of the maps during construction. Two classes of maps were produced: a high confidence "skeletal" set composed of 544 PCR based markers, and a more highly annotated "framework" set containing maps of 1,123 markers. Genetic map locations within the framework maps are provided for an additional 1,758 loci without statistically unique interval assignments.

Algorithms↗
PubMed1994

Isolation of yeast artificial chromosome clones from 54 polymorphic loci mapped with high odds on human chromosome 4.

We constructed a yeast artificial chromosome (YAC) framework map of human chromosome 4 by screening a YAC library with 63 polymorphic DNA markers located on the chromosome. These genetic markers are from two framework meiotic maps that had previously been constructed by two research groups, and are placed on the two maps with odds for their order of 1000:1 or greater. In addition to isolating and determining the sizes of 141 YAC clones for 54 of these markers, we combined the two framework meiotic maps to produce a single integrated map. These combined maps and the YAC clones provide a set of extended DNA loci ordered at high odds that can be used to isolate additional polymorphic loci and genes, and to serve as a framework for obtaining a higher resolution physical map of the chromosome.

Chromosome Mapping↗
PubMed1994

Localization of the achondroplasia gene to the distal 2.5 Mb of human chromosome 4p.

Achondroplasia has been mapped to 4p16.3 using 18 multigenerational families with achondroplasia and 10 short tandem repeat polymorphic markers from this region. No evidence of genetic heterogeneity was found. Analysis of a recombinant family localizes the achondroplasia locus to the 2.5 Mb region between D4S43 and the telomere. Multipoint linkage analysis favors placement telomeric of D4S412. The establishment of closely linked markers will facilitate positional cloning of the achondroplasia gene and permit prenatal diagnosis of homozygous achondroplasia for at risk couples.

Achondroplasia↗
PubMed1994

Prolongation of the prothrombin time after organophosphate poisoning.

Prolongation of the prothrombin time owing to a transient reduction in factor VII activity is described in a 14-month-old child with organophosphate poisoning. Correction after vitamin K administration suggested an organophosphate-related effect on vitamin K-dependent factor VII activity. Historically, coagulation screening has not been routinely recommended after organophosphate intoxications. We suggest, however, that routine screening in such patients may be important. A brief review of organophosphate poisoning and the unique features of our case are presented.

Acetylcholinesterase↗
PubMed1994

Dosimetric problems at low monitor unit settings for scanned and scattering foil electron beams.

Electron beam dosimetry at low monitor unit (MU) settings is important for dosimetric applications. Dose linearity, beam flatness, and beam energies were studied at low MU settings with various dose rates for different types of linear accelerators. It is observed that for the scattering foil units, the dose/MU is a smooth function of MU for all beam energies. Discrepancies in dose/MU are highest at the lowest MU. Significant variation (5%-245%) in dose linearity is observed among various linear accelerators at low MU settings. Dose rate has no effect on the dose linearity for all energies for the scattering foil units tested. On the contrary, for the scanned beam, there is no predictable pattern as dose/MU is random in nature and varies with time and beam energy. The maximum dosimetric error is observed for the highest energy beam where the beam width is most narrow. Using film, the beam uniformity was noticed to be very poor at low MU and high energy for scanned beams. The beam uniformity and dose linearity are random at low MU due to the random nature of the scan cycle. Under the adverse conditions, the deviation in dosimetric parameters was observed up to 200 MU.

Electrons↗
PubMed1994

Radiation-induced fibrosis: the structure/function relationship.

Fibrosis is a frequent complication of therapeutic radiation delivered to organ sites such as the thorax and pelvic region. We investigated the relationship between function, and biochemical and structural changes in the lung and colon of CBA mice irradiated with 240 kV X-rays. Progressive changes in lung function, as evidenced by increased breathing rates were observed out to 6 months post-irradiation. Biochemical studies demonstrated increased metabolism (synthesis and breakdown) of collagen around 6 months after irradiation, but provided no evidence of net collagen accumulation. Analysis of collagen isotypes revealed a slight increase in the ratio of types I and III. In the colons of irradiated mice, there was a progressive decrease in compliance out to 14 months post-irradiation. Collagen and total protein synthesis and breakdown rates were increased at early times, and returned to control levels by 4 months. No net accumulation of collagen was observed at any time. The ratio of collagen type I to III was increased at one year post-irradiation. We conclude that, in the CBA mouse, late functional changes after X-irradiation are not the result of a build-up of excessive connective tissue, although changes in collagen metabolism may occur relatively early on in the response to radiation.

Animals↗
PubMed1994

Childhood idiopathic thrombocytopenic purpura: association with human parvovirus B19 infection.

PURPOSE: Infection with human parvovirus B19 is the most common cause of transient aplastic crisis in patients with chronic hemolytic anemia. Multiple reports of children with simultaneous B19 infection and thrombocytopenia as well as the known association between experimental B19 infection and thrombocytopenia prompted us to hypothesize that B19 may be associated with childhood idiopathic, or immune, thrombocytopenic purpura (ITP). Because there is a paucity of evidence regarding a viral etiology for ITP, we performed a comprehensive study to explore its possible relationship to B19 infection. PATIENTS AND METHODS: Thirty-five previously healthy children with ITP were studied prospectively. Bone marrow and peripheral blood were analyzed for B19 DNA using the polymerase chain reaction (PCR). Serum was analyzed for anti-B19 immunoglobulin (Ig) M and IgG antibodies using a B19 VP1 antigen-based enzyme-linked immunosorbent assay. Fourteen healthy children served as controls for peripheral blood PCR and serologic analyses. RESULTS: The presenting clinical and laboratory features of the study population were typical of classic ITP. Seventeen of the 35 patients (49%) had evidence of B19 DNA in the peripheral blood, bone marrow, or both. Six of 35 (17%) had anti-B19 IgM antibodies. Eight of 35 (23%) were anti-B19 IgG seropositive. The control group had no positive PCR or anti-B19 IgM specimens. CONCLUSIONS: Our results suggest that infection with human parvovirus B19 may be associated with childhood ITP. More investigation is warranted regarding the role of PCR methodology and serologic detection methods in defining B19 pathobiology as it relates to ITP.

Adolescent↗
PubMed1994

Ticlopidine: a new antiplatelet agent for the secondary prevention of stroke.

Ticlopidine hydrochloride, an inhibitor of platelet aggregation that has been approved for use in the United States for secondary stroke prevention, may be more effective than aspirin for the secondary prevention of stroke, but this advantage decreases greatly over time. The pharmacology, adverse effects, efficacy, drug interactions, and indications for ticlopidine are discussed here with summaries of various clinical trials. The drug is more costly than aspirin, and patients must have complete blood counts during the first 3 months of therapy. It is recommended for those who cannot take aspirin and may be more effective in certain groups--nonwhites, diabetics, and women and those with vertebrobasilar ischemia, intermittent claudication, unstable angina, and nonproliferative retinopathy.

Cerebrovascular Disorders↗