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Biomedical subjects

M Janson

Publications and source records attributed to M Janson.

At least 19 recordsLinked to original sources
PubMed1996

Continuous intracisternal and high cervical intrathecal bupivacaine analgesia in refractory head and neck pain.

BACKGROUND: The upper cervical component of the spinomesencephalic tract and cranial nerves V, VII (nervus intermedius), IX, and X are involved in mechanisms of acute and chronic pain from head and neck structures. To date there is no reliable method for relief of refractory pain (i.e., pain that cannot be relieved by conventional pharmacologic therapies) from these structures. Therefore, we explored continuous intracisternal infusion of bupivacaine for the treatment of refractory pain of the head and neck. METHODS: Intracisternal catheters were inserted in 13 adults with refractory nonmalignant (n = 4) and malignant (n = 9) pain from the head, face, mouth, neck, and upper extremities; 0.5% plain bupivacaine was infused continuously at rates of 1-7 (median 1.5) mg/h with optional bolus doses of 0.5-2.0 mg 4-2 times/h. The efficacy was assessed from pain relief (daily VAS(max), VAS(min), and VAS(mean) scores 0-10), daily doses of intracisternal bupivacaine and total opioid (expressed as mg parenteral morphine-eq), amount of nocturnal sleep, and rates of adverse effects. RESULTS: The 13 patients were treated for 3-182 days (median 37, total 712 days), 3 patients being treated at home for 10-112 days (median 88, total 210 days). In one patient, the efficacy of the treatment could not be estimated because of advanced senility. Eleven of the remaining 12 patients obtained acceptable pain relief with daily doses of intracisternal bupivacaine ranging from 20 to 118 mg (median 37 mg): VAS(mean) scores decreased from 7 to 2, mean pain relief increased for 30% to 80%, total opioid daily dose decreased from 53 to 36 mg parenteral morphine-eq, and nocturnal sleep increased from 2 to >6h (all figures are median values). Speech, eating, walking, and natural functions were generally not affected. Side effects such as tiredness and malaise, somnolence and sleep, feeling of coldness in the neck and skull base, transient post-spinal puncture headache, paresthesias, hoarseness, dysphagia, transient paresis of the upper/lower extremities, episodic miosis and conjunctival hyperemia, and transient orthostatic arterial hypotension were each observed in one or two patients. No patient presented clinical evidence of phrenic nerve paralysis. There was no nausea or vomiting. No persistent neurologic deficit or death could be attributed to the intracisternal pain treatment. CONCLUSIONS: Continuous intracisternal infusion of bupivacaine may be a useful method in exceptional, well selected patients with refractory pain from the head and neck structures. Further studies are necessary to establish the indications and the safety of the method.

Adult↗
PubMed1996

EDTA chelation therapy in the treatment of vascular disease.

Ethylenediamine tetraacetic acid (EDTA) chelation therapy has been used for decades for the treatment of vascular disease, alone or in combination with other treatments. This article includes a historic review of the research literature, current evidence of effectiveness, potential mechanisms of action of EDTA, and some brief case reports. The authors conclude that EDTA chelation therapy is a valuable therapeutic option for vascular disease, either alone or in conjunction with standard treatment protocols.

Chelating Agents↗
PubMed1994

Physical mapping of the NF2/meningioma region on human chromosome 22q12.

Loss of genetic information from chromosome 22 has been implicated in the development of neurofibromatosis type 2, meningioma, and several other neoplasia. Molecular studies indicate that genes within chromosomal band 22q12 may be involved in tumorigenesis. We have mapped 29 loci into 16 groups in this region, using pulsed-field gel electrophoresis, fluorescence in situ suppression hybridization, and somatic cell hybrid mapping. The region spans more than 5 Mb of genomic DNA and contains the genes for neurofibromatosis type 2 and meningioma. The order of loci presented here provides the framework for the fine mapping of this region using cosmids and yeast artificial chromosomes, and it facilitates the speedy cloning of novel genes from 22q12.

Cell Line, Transformed↗
PubMed1994

A constitutional mutation within the retinoblastoma gene detected by PFGE.

Retinoblastoma may be caused by constitutional mutations in the retinoblastoma gene which segregates as an autosomal dominant inherited predisposition for developing retinoblastoma tumours. Since 75% of these cases are new mutations, there is a need for methods to identify carriers of such germ-line mutations, so that informed genetic counselling is available to patients and close relatives. We have used pulsed-field gel electrophoresis in screening 20 unrelated cases with bilateral retinoblastoma. One constitutional mutation could be detected, and was found to be caused by a balanced chromosome (4;13) translocation with the breakpoint within intron 17 of the retinoblastoma gene.

Chromosomes, Human, Pair 13↗
PubMed1994

Intragenic reorganization of RB1 in a complex (4;13) rearrangement demonstrated by FISH.

Reciprocal chromosome translocations with no apparent loss of material are the most common de novo structural rearrangements in man. The large majority of these cases have been characterized cytogenetically but very few have been investigated at the molecular level. Using fluorescence in situ hybridization (FISH) we have studied the organization of the tumor suppressor gene RB1 in a patient with retinoblastoma and a rearrangement between chromosomes 4 and 13. In addition to the hybridization signal on the normal chromosome 13, three distinct sites of hybridization of RB1 probes on the translocated chromosomes were detected. These findings show that a complex rearrangement occurred involving at least three breaks on chromosome 13, two of them in the RB1 gene. This also demonstrates that FISH, which offers resolution between that of fine molecular methods and classical cytogenetics, is a valuable tool for investigating organization of sequences at breakpoints of chromosomal rearrangements.

Cell Line, Transformed↗
PubMed1992

Isolation and mapping of polymorphic cosmid clones used for sublocalization of the multiple endocrine neoplasia type 1 (MEN1) locus.

Multiple endocrine neoplasia type 1 (MEN1) is characterized by neoplasia of the parathyroids, the pancreas, and the pituitary. Tumorigenesis involves unmasking of a recessive mutation at the MEN1 locus, which has been mapped to the centromeric part of chromosomal region 11q. In order to localize the MEN1 gene further and to make its isolation possible, a number of new markers were isolated. Two radiation-reduced somatic cell hybrids were identified that only contained markers close to and flanking the MEN1 region. DNA from these hybrids was used for the construction of a cosmid library, and clones containing human inserts were isolated. In addition, cosmid clones were isolated for locus expansion of 7 other markers that were mapped to the 11q12-13.2 region. The 33 newly isolated clones together with 25 previously published markers from this region were analyzed in a panel of radiation-reduced somatic cell hybrids. From the hybridization pattern, the region was divided into 11 parts. New restriction fragment length polymorphisms were identified in 7 of the newly isolated cosmid clones and in one plasmid. These were then used to sublocalize meiotic cross-overs more precisely in two MEN1 families, thus refining the mapping of the disease gene.

Blotting, Southern↗
PubMed1992

Contiguous localization of the genes encoding human insulin-like growth factor binding proteins 1 (IGBP1) and 3 (IGBP3) on chromosome 7.

In extracellular fluids the insulin-like growth factors (IGFs) are bound to specific binding proteins (IGBPs). The genes for two members of this protein family have been mapped, the IGBP1 gene to human chromosomal region 7p14-p12 and the IGBP2 gene to region 2q33-q34. In this study, somatic cell hybrid analysis indicated that IGBP3 is also located on chromosome 7. Pulsed-field gel electrophoresis was used to demonstrate the close physical linkage between IGBP1 and IGBP3. Overlapping cosmid clones encompassing these genes were isolated, and restriction endonuclease mapping showed that the genes are arranged in a tail-to-tail fashion separated by 20 kb of DNA. Further characterization of the IGBP1 DNA sequence disclosed a duplication of the intron 3-exon 4 junction within the third intron. In addition, we report RFLPs for ApaLI and TaqI in the IGBP1 locus.

Amino Acid Sequence↗
PubMed1992

Sublocalization of the multiple endocrine neoplasia type 1 gene.

Tumorigenesis in multiple endocrine neoplasia type 1 (MEN 1) involves the unmasking of a recessive mutation at the MEN 1 locus which has been mapped to chromosomal region 11q11-13. By analyzing 58 DNA markers on a panel of radiation-reduced somatic cell hybrids, the region encompassing the MEN 1 gene was divided into nine subregions. Pulsed field gel electrophoresis analysis of markers within subgroups showed that the recombination rate around the MEN 1 locus is high. Combined linkage analysis in MEN 1 families and deletion mapping in MEN 1-related tumors suggest the MEN 1 gene is located centromeric to D11S807 and telomeric to PYGM.

Animals↗
PubMed1991

Detailed physical map of human chromosomal region 11q12-13 shows high meiotic recombination rate around the MEN1 locus.

We have constructed a physical map of the region q12-13 on chromosome 11 by combining data generated from a panel of radiation-reduced somatic cell hybrids and pulsed-field gel electrophoresis (PFGE). Twenty different genetic markers have been sublocalized and ordered within this region and a total of 8.0 megabases has been mapped in detail using rare-cutting restriction endonucleases and PFGE. In two instances, the long-range restriction PFGE map spans the total distance between pairs of loci that have been previously mapped by genetic linkage in reference families. Comparison of this physical map with the available linkage map indicates a great variation in the recombination frequency over the region. The recombination rate is higher than expected, particularly for markers flanking the MEN1 region. Thus, for the closest pair of linked markers on the centromeric side, one centimorgan corresponds to approximately 300 kilobases, and for markers on the telomeric side, one centimorgan corresponds to approximately 350-600 kilobases.

Animals↗
PubMed1991

[Heterotopic pancreatic cyst of the stomach wall].

A 28 year old female was admitted to the hospital with dolorous postprandial swelling of the left upper epigastrium, occurring since the recent death of her husband. After an asymptomatic interval of eight years pains similar to biliary colics occurred increasing in duration, intensity and frequency during the following year. Sonography and computer-tomography indicated a pseudocyst of the pancreascauda adjacent to the left lobe of the liver, spleen and gastric wall. Laparotomy revealed the diagnosis of a heterotopic cyst of the pancreas of fist-size localized intramurally in the gastric corpus which was totally resected. Histologically a granulomatous partially transformed cyst in a heterotopic pancreas was identified. The patient became symptom-free after the operation.

Adult↗
PubMed1990

Constitutional deletions predisposing to retinoblastoma.

Patients with the heritable form of retinoblastoma carry a constitutional mutation in the retinoblastoma locus in heterozygous form. The majority of such cases are the result of new mutations, which may be inherited by their offspring. We have identified such constitutional mutations within the retinoblastoma locus in 3 out of 66 investigated unrelated gene carriers, using Southern blot analysis and Rb-gene cDNA-probes. The identified mutations were found to be located in different regions of the gene. These analyses may be used to identify or exclude close relatives at risk for the disease. In 2 of the 3 cases, the identified aberrations were used for informed genetic counselling of relatives.

Blotting, Southern↗
PubMed1988

Prediction of the risk of hereditary retinoblastoma, using DNA polymorphisms within the retinoblastoma gene.

Using molecular cloning, we earlier isolated the "retinoblastoma gene"; mutations or deletions at this locus are associated with the hereditary predisposition to some human cancers, especially retinoblastoma and osteosarcoma. To develop diagnostic tests for such a predisposition, we identified restriction-fragment-length polymorphisms (RFLPs) within the retinoblastoma gene and tested their usefulness in predicting the risk of cancer in 20 families with members who had hereditary retinoblastoma. We were able to make predictions in 19 of the 20 kindreds. In 18 kindreds, we demonstrated a consistent association of marker RFLPs with the mutation predisposing to retinoblastoma. In the 19th kindred, there may be a lack of cosegregation of the DNA polymorphisms within the gene and the site of the mutation predisposing to retinoblastoma. However, there is uncertainty about the clinical diagnosis of the retinal lesion in a key member of this kindred; if the lesion is not a retinoblastoma, there is no discrepancy between the DNA polymorphisms and the retinoblastoma trait. We conclude that it is feasible and clinically useful to use these DNA polymorphisms to determine the risk of cancer.

Alleles↗
PubMed1986

Quantitative determination of platelet surface alloantigens using a monoclonal probe.

A monoclonal antibody with specificity for the Fc portion of IgG was used to determine the number of IgG alloantibody molecules bound at saturation to alloantigens of the PlA1 and HLA systems on normal human platelets. In preliminary studies, it was found that the number of cell-bound IgG molecules recognized by this probe correlates well with the number measured by electroimmunoassay, an independent measure of alloantibody binding. PlA1-positive platelets could be divided into two groups binding 34,000-43,000 or 19,000-24,000 alloantibody molecules. Family studies and studies with a cytolytic assay showed that the former group is homozygous and the latter heterozygous for PlA1. Because the number of glycoprotein IIIa (GPIIIa) molecules carrying the PlA1 determinant on the surface of normal platelets is thought to be about 40,000, these findings suggest that each GPIIIa molecule carries one PlA1 determinant. The number of class I HLA molecules expressed on normal platelets was considerably smaller than the number of PlA1 determinants, ranging from 4400 to 10,000 (HLA-A2), 870 to 8400 (Bw4), and 1300 to 5800 (Bw6). Preliminary analysis indicates that stronger or weaker expression of Bw4 and of Bw6 correlates with certain "private" HLA-B determinants carried on the HLA-B molecule as found in previous studies using an indirect method to measure alloantigen density. These findings appear to explain why antibodies reactive with platelet-specific antigens such as PlA1 react more strongly with platelets than HLA-specific antibodies in most serologic tests. The weak expression of HLA determinants on platelets of some subjects may account for the less than perfect correlation between in vitro compatibility tests and post-transfusion platelet survivals observed in most studies.

Antibodies, Monoclonal↗
PubMed1986

Reproducibility of occlusal findings. A comparison between clinical and articulator analyses.

The occlusal relationship may be examined clinically in the patient's mouth and on models mounted in an articulator. For the purpose of comparing the reproducibility of the two methods, the occlusion of 10 subjects was analyzed twice with at least 1 week's interval. Certain variations were demonstrated with both methods. Overall reproducibility of tooth contact was observed more frequently in the articulator than in the mouth. The methods showed an equal degree of consistency for measurements of slide in centric. However, when subjects were classified by the extent of occlusal interference, the findings of the clinical analysis seemed to be more reproducible than those recorded by means of the articulator.

Adolescent↗