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Biomedical subjects

M B Larsen

Publications and source records attributed to M B Larsen.

At least 19 recordsLinked to original sources
PubMed2005

Quantification of tissue inhibitor of metalloproteinases 2 in plasma from healthy donors and cancer patients.

Tissue inhibitor of metalloproteinases (TIMP)-2 is a highly conserved molecule, which binds both active and latent matrix metalloproteinase (MMP)-2. TIMP-2 is also involved in the activation of MMP-2 on the cell surface. A quantitative enzyme-linked immunosorbent assay (ELISA) was established and optimized for measurement of TIMP-2 in plasma. The capturing antibody in the ELISA was a monoclonal, while the detecting antibody was a chicken polyclonal antibody recognizing the native form of human TIMP-2. The levels of TIMP-2 were measured in ethylenediaminetetraacetic acid (EDTA) and citrate plasma from healthy donors. The median values were determined as 163 ng/ml (n = 186) with a range of 109-253 ng/ml for EDTA plasma and 139 ng/ml (n = 77) with a range of 95-223 ng/ml for citrate plasma. The TIMP-2 concentration in citrate plasma from 15 patients with advanced, stage IV breast cancer had a median value of 160 ng/ml, only slightly higher but statistically distinguishable from the level found in citrate plasma from the healthy donors. In addition, the TIMP-2 concentration in EDTA plasma from colorectal cancer patients revealed a significantly higher level in plasma from patients with Dukes stage A (P = 0.01) compared with patients with more advanced Dukes stages.

Adult↗
PubMed1999

Functional analysis of a novel human serotonin transporter gene promoter in immortalized raphe cells.

To investigate the structural basis for genetic regulation of the human serotonin transporter gene, a 1.8 kb fragment upstream to the cap site was cloned and sequenced. The promoter possesses a polymorphic repeat region with 16 and 14 repeats, respectively. Both were cloned and characterized. The promoter sequence revealed an internal 379 bp fragment not reported in previous publications. This novel fragment contains consensus sequences for several transcription factors including SpI and GATA. DNA from 48 unrelated individuals was PCR amplified, in this region, to test for allelic variations. All were found to possess the additional 379 bp fragment. The integrity of the promoter was furthermore confirmed by genomic Southern blotting. The promoter activity was analyzed by reporter gene assays in neuronal and non-neuronal serotonergic cell lines. In immortalized serotonergic raphe neurons, RN46A, three cis-acting, cell specific, activating elements and a silencer were located. One of the activators and the silencer are located in the repeat region and one activator is positioned in the novel fragment. A fourth activating element was found to be active in both RN46A cells and in a non-neuronal serotonergic cell line, JAR. A 3.5 kb fragment from intron 1 was cloned and found to possess cell specific activity in JAR cells indicating the presence of an alternative promoter in intron 1.

Animals↗
PubMed1998

A molecular, cytogenetic, and clinical evaluation of mosaic tandem duplication 17p and Charcot-Marie-Tooth type 1A neuropathy.

An 8 year old girl with partial duplication of the short arm of chromosome 17 had a mosaic 46,XX,der(17)?del(17)(p12)dup(17) (p11.2p12).ish dup(17)(p11.2p13.3)(D17S 379x2, p53x2, D17S122x2, D17S29+) karyotype. The extent of mosaicism was 20% in lymphoblasts and 100% in fibroblasts. Fluorescence in situ hybridisation (FISH) proved invaluable in defining the abnormality precisely. The cytogenetic morphology by FISH assay ruled out a microdeletion of the Miller-Dieker syndrome (MDS) region. However, there was no MDS deletion but a duplication of this region. The duplication was extensive and included proximal p53 and D17S122, Charcot-Marie-Tooth type 1A (CMT1A), but not D17S29, the Smith-Magenis syndrome (SMS) region. This patient has the clinical features and generalised decreased peripheral nerve conduction velocity characteristic of CMT1A. The clinical management of paediatric cases of mosaic trisomy 17p cases would ential testing for CMT1A duplication. If duplicated, a decrease in nerve conduction velocity (NCV) of the peripheral motor neurones would be necessary to ensure the manifestation of CMT1A neuropathy. The parents of probands with delayed NCV should be counselled about the risk of CMT1A in later life.

Charcot-Marie-Tooth Disease↗
PubMed1995

MR and CT imaging patterns in post-varicella encephalitis.

The aim of the investigation was to determine the patterns of cerebral involvement on computed tomography (CT) and magnetic resonance (MR) imaging in post-varicella encephalitis. Four children between the ages of 2 and 11 years presented over a 5-year period with a diagnosis of post-varicella encephalitis. Their imaging studies and clinical data were reviewed retrospectively. The medical histories of all four children were noncontributory except for recent bouts of chickenpox 1 week to 3 months prior to hospitalization. Three children presented with parkinsonian manifestations. Bilateral, symmetric hypodense, nonenhancing basal ganglia lesions were found on CT. These areas showed nonenhancing low signal intensity on T1-weighted images and high signal intensity on T2-weighted images on MR. One child presented with diffuse, multiple gray and white matter lesions of similar imaging characteristics; some lesions, however, did enhance. This child had no gait disturbances. Post-varicella encephalitis can produce two patterns of dramatic CT and MR findings. With an appropriate history and clinical findings, varicella as a cause of bilateral basal ganglia or diffuse cerebral lesions can be differentiated from other possible etiologies which include trauma, anoxia, metabolic disorders and demyelinating diseases.

Chickenpox↗
PubMed1995

Outcome of children with opsoclonus-myoclonus regardless of etiology.

Within the past 11 years, 11 patients with opsoclonus and myoclonus, with or without a history of neuroblastoma, have been admitted to Children's Memorial Hospital. Eight of the 11 children had an occult neuroblastoma. Eight children have had subsequent delayed development with motor incoordination and speech delay (7 with neuroblastoma, 1 without). Nine of 11 children initially were treated with ACTH, 1 child was treated with prednisone, and 1 was not treated. Nine of the 10 children who were treated had recurrences of symptoms during the gradual withdrawal or discontinuation of ACTH. Often the ACTH had to be restarted or increased, although several times the episodes were self-limited, not requiring treatment after ACTH was withdrawn. We found prednisone was ineffective in controlling opsoclonus-myoclonus regardless of etiology. The majority of children with opsoclonus-myoclonus, regardless of etiology, have developmental delay, more severe and at a higher rate than previously reported. When a neuroblastoma was present, tumor removal did not improve symptoms. Although limited in size, our study indicates patients with opsoclonus-myoclonus without an associated neuroblastoma have a better chance for normal neurologic development (2/3 versus 1/8).

Adrenocorticotropic Hormone↗
PubMed1994

Long-term outcome in children with opsoclonus-myoclonus and ataxia and coincident neuroblastoma.

We reviewed the neurologic and developmental courses in 10 children with opsoclonus-myoclonus ("dancing eyes syndrome") and neuroblastoma. All patients are alive without evidence of neoplastic disease after 8+ to 111+ months of follow-up. All had localized disease and 50% had extraabdominal tumors. Neuroblastomas of nine children had favorable Shimada histologic characteristics, and all tumors had single copies of the N-myc oncogene. After neuroblastoma resection, all patients had persistent opsoclonus-myoclonus or ataxia that responded to therapy with adrenocorticotropic hormone. Nine children had relapses of neurologic symptoms. Three years after resection, six of seven patients with sufficient follow-up were free of symptoms and had discontinued therapy. However, nine children had chronic neurologic deficits, including cognitive and motor delays, language deficits, and behavioral abnormalities. All six patients in educational programs required special assistance. Five children required physical, occupational, or speech therapy. Long-term developmental and cognitive problems should be anticipated in patients with neuroblastoma who have opsoclonus-myoclonus or ataxia or both, and early intervention should be instituted to try to minimize these deficits.

Abdominal Neoplasms↗
PubMed1992

New variant in exon 3 of the proteolipid protein (PLP) gene in a family with Pelizaeus-Merzbacher disease.

A C--greater than G transversion has been found in exon 3 of the PLP gene of affected males and their mother in a single sibship with Pelizaeus-merzbacher disease (PMD). The transversion should not result in an amino acid change in the protein but it does result in the loss of a HaeIII restriction endonuclease cleavage site. It is concordant with the disease in this family. One-hundred-ten unrelated X chromosomes are negative for this mutation. No other sequence defect was found in the PLP exons of the affected males. The cause of disease in this family remains unknown, but the association between this rare mutation and PMD is intriguing. The mutation can serve as a marker for following segregation of the PLP gene.

Base Sequence↗
PubMed1983

Noninvasive CT diagnosis of infantile Alexander disease: pathologic correlation.

Noninvasive computed tomography provided the initial, accurate diagnosis of a necropsy-proven case of infantile Alexander disease, demonstrated serial changes in the intensity and distribution of leukodystrophy, and documented a progressive alteration of brain density from abnormally high attenuation to abnormally low attenuation as the disease advanced.

Biopsy↗
PubMed1983

Calcified metastases to the brain in a child: case report.

A child with calcified intracranial metastases of undifferentiated sarcoma of the mediastinum is described. Calcifications in metastatic neoplasms to the brain are rare, but must be considered in the differential diagnosis of intracranial calcified lesions.

Brain Neoplasms↗
PubMed1978

Radiation myelopathy in children.

Three children, 1 with medulloblastoma, 1 with anaplastic cerebellar tumor, and 1 with acute lymphocytic leukemia, received craniospinal irradiation with an estimated cord dose between 1,100 and 1,200 rets. All 3 patients after a latent period of seven to eight months developed subacute transverse myelopathy. The myelopathy was cervical in 2 patients and thoracic in 1. Spinal fluid examination showed high protein levels in 2 patients. Myelography demonstrated a swollen cord in 2 patients and normal appearance in 1. Autopsy in 1 patient disclosed a necrotizing myelopathy. The findings suggest that children tolerate less well than adults what previously have been considered safe doses of radiation to the spinal cord.

Adolescent↗