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Biomedical subjects

M L Anderson

Publications and source records attributed to M L Anderson.

At least 109 records · Page 6Linked to original sources
PubMed1988

Perinatal medical negligence closed claims from the St. Paul Company, 1980-1982.

One hundred fifty-three closed claims involving perinatal injury or death filed from 1980 through 1982 with the St. Paul Fire and Marine Insurance Company were studied. The claims included were those in which an indemnity was paid or $1,000 or more was expended on the legal defense. Five obstetricians reviewed these cases to identify obstetric and neonatal risk factors. In addition, cases were classified as to the presence or absence of medical negligence. Most of the complications leading to claims arose during labor and delivery. Many claims resulted from the failure to evaluate or treat in a manner consistent with accepted standards of care. Many lacked documentation of the physician's recognition of the risk factors involved. Low Apgar scores at both one and five minutes were the newborn risk factors seen most commonly. In the opinion of the reviewers, medical negligence occurred in 47% of the cases. Indemnity payment occurred with most of the claims judged to be associated with medical negligence. Payment to the claimant was made in a number of cases in which the reviewer thought no malpractice occurred. These results suggest that improvements may be needed in prenatal and perinatal health care as well as in the legal system used to address the problem of perinatal medical negligence.

Birth Injuries↗
PubMed1987

A study of mechanisms of carcinogenesis by gene transfer of oncogenes into mammalian cells.

Recent work has shown that individual oncogenes can be involved in several steps of the multistage process of carcinogenesis. Evidence comes from studies on the expression of cloned oncogenes transfected into early passage mammalian cells and into immortalized non-tumorigenic cell lines. Transformation of epithelial cells in vitro with cloned cellular and viral oncogenes is of special interest since most human tumors are of epithelial origin. An important aspect of cell transformation by oncogenes is the induction of transforming growth factors (TGFs). The role of oncogenes in differentiation has been examined by introducing the human myc and mutant T24 Ha-ras1 genes into mouse erythroleukemic cells which were then induced to differentiate. In several clones differentiation was inhibited by myc or ras genes. Studies are reported using oncogenes linked to transcriptional control elements that can be regulated in vitro, such as the human metallothionein (hMT-IIA) promoter region, by cadmium and dexamethasone. Phenotypic properties of transfectants including morphological transformation, anchorage dependence and TGF release are shown to be dependent on the regulators of the hMT-IIA control region.

Animals↗
PubMed1987

Possible cooperativity in crossbridge detachment in muscle fibers having magnesium pyrophosphate at the active site.

When rabbit psoas muscle fibers bathed in solutions containing the ATP analogue magnesium pyrophosphate (MgPPi) are first stretched rapidly and then held isometric, a force is generated during the stretch which decays during the subsequent isometric period (Schoenberg, M., and E. Eisenberg. 1985. Biophys. J. 48:863-871). Previously we showed that the force decay is due to crossbridge heads detaching and reattaching in positions of lesser strain, the rate of decay of force reflecting the crossbridge detachment rate constants. Since the crossbridge detachment rate constants with MgPPi bound to the active site are so much faster than without analogue bound, at subsaturating concentrations of analogue, if the heads act independently and nucleotide association and dissociation is rapid, the rate of force decay should simply be proportional to the number of heads with bound analogue. That is, the analogue concentration dependence of the rate of force decay should have the same form as the Michaelis-Menten equation. Here we report that the concentration dependence of the rate of force decay is not described by the Michaelis equation, but is instead sigmoidal. This suggests possible cooperativity in the detachment of the crossbridge heads, the amount of cooperativity being described by an interaction coefficient of approximately 2. One idea put forward to explain the data is that both of the heads of a crossbridge may need to bind analogue before the crossbridge can relax a substantial fraction of the tension it supports.

Adenosine Triphosphate↗
PubMed1987

Intracarotid chemotherapy with 1,3-bis-(2-chloroethyl)-1-nitrosourea (BCNU) in 5% dextrose in water in the treatment of malignant glioma.

After radiotherapy, 20 patients, 18 with documented progression of malignant glioma and 2 with Grade II astrocytoma, received a total of 52 courses of intracarotid 1,3-bis-(2-chloroethyl)-1-nitrosourea (BCNU) at a dose of 150 mg/m2 dissolved in 5% dextrose in water. The patients were treated at 6-week intervals for a maximum of five courses of chemotherapy per patient. Response to treatment was analyzed on computed tomographic scans by measuring the volume of the enhancing tumor and any central low density. From these data, tumor doubling times ranging from 110 to 968 days were obtained. An 11 to 60% reduction in enhancing tumor volume was noted in 8 patients, 2 of whom had a greater than 50% decrease in tumor volume. One patient had no change in tumor volume 110 weeks after the initiation of BCNU chemotherapy. Four patients had tumor in more than one vascular territory; tumor growth was arrested in the perfused territory, but continued in the nonperfused area. In 1 of the 4 patients, tumor also grew along a shunt catheter tract and spread over the surface of the ipsilateral hemisphere. One patient developed clinically asymptomatic leukoencephalopathy after five courses of BCNU. Two patients had postradiation leukoencephalopathy before BCNU treatment. Seventeen patients had peritumoral low density with mass effect after BCNU; thus, the true incidence of BCNU-related leukoencephalopathy could not be determined. All patients experienced transient unilateral orbital pain during the infusion and scleral erythema that lasted for several hours afterward. Loss of vision was noted in 2 patients, although it seemed to be related to the therapy in only 1 patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Immunoglobulin containing cells in the tracheobronchial tree of cattle: relationship to age.

The cells of the pulmonary immune system of cattle were examined using an immunoperoxidase technique to identify cytoplasmic immunoglobulins. Cells reacting immunohistochemically with bovine IgG1, IgG2, IgA and IgM antisera were quantified in formalin-fixed paraffin embedded tissues from systematically selected sites within the tracheobronchial tree. Non-pneumonic lungs were selected for study from five groups of cattle which ranged in age from neonatal calves to aged adult cattle. Age associated differences were found. Neonatal calves lacked immunoglobulin containing cells (ICC). The numbers of ICC in 18-month-old cattle were significantly greater than in other age groups. The relative frequency of each immunoglobulin class among the cells of the airway mucosa was IgA greater than IgG1 greater than IgG2 greater than IgM for all cattle four months and older (n = 20) with an IgA to IgG1 ratio of 3.46. All airway categories from trachea to bronchiole had similar proportions of cells in each immunoglobulin class although the cell density declined in the distal airways.

Aging↗
PubMed1986

Bronchus associated lymphoid tissue in the lungs of cattle: relationship to age.

The occurrence and morphological features of bronchus associated lymphoid tissue (BALT) were examined by light and electron microscopy in the non-pneumonic left lungs of five age groups of cattle from neonate to aged adult. The amount of BALT was correlated with age. It was absent in neonatal lungs and increased progressively with age until it declined in aged adult cattle. Within age groups the occurrence and morphology of BALT was variable. Widely scattered lymphoid aggregates were the predominant morphological type of BALT in the bovine lung. Follicular development in BALT foci was less frequent and quite variable within individual lungs. Morphologically distinct lymphoepithelium overlying BALT foci could not be demonstrated in non-pneumonic bovine lungs.

Aging↗
PubMed1985

Regional mapping of two human immunoglobulin V lambda genes and analysis of the V lambda locus in chronic myeloid leukaemia.

The human immunoglobulin V lambda locus has been studied in relation to chromosomal translocations involving chromosome 22. DNA probes for two V lambda genes which belong to different subgroups and do not cross hybridize, were used to show that both V lambda genes are located on the Philadelphia chromosome in chronic myeloid leukaemia (CML). Both genes map in band 22q11 to a region that is bounded on the distal side by the breakpoints for CML 9:22 translocations and on the proximal side by the breakpoint for an X:22 translocation. We have found no evidence for rearrangements or amplification of either V lambda gene in CML, in either the chronic or acute phases of the disease. In K562 cells which are derived from the pleural effusion of a patient with Ph1-positive CML, there appears to be no rearrangement of the V lambda genes, but they are both amplified about four times. We have estimated that the minimum size for the amplification unit in K562 cells is 186 kb.

Animals↗
PubMed1985

Cloning and sequence analysis of an Ig lambda light chain mRNA expressed in the Burkitt's lymphoma cell line EB4.

A cDNA library was constructed from the mRNA of the Ig lambda producing Burkitt's lymphoma cell line, EB4. Overlapping clones encompassing the coding sequence of the Ig lambda mRNA were isolated and sequenced. The predicted amino acid sequence shows a short hydrophobic leader peptide and a mature polypeptide of 217 residues in which V, J and C regions can be distinguished. The V region belongs to subgroup VI and has greatest homology (80%) with the Amyloid-AR protein. The constant region is the Kern- Oz+ isotype. Probing normal human DNA with the subcloned V lambda coding sequence detects one gene at high stringency and a family of 11 members at low stringency. To date, no restriction enzyme site polymorphisms have been detected. The V lambda VI gene is rearranged on both chromosomes of EB4 and is deleted on both chromosomes in the Burkitt's lymphoma cell line BL2.

Base Sequence↗
PubMed1985

Investigation of obstetric malpractice closed claims: profile of event.

The files of 220 obstetric closed-claim cases were reviewed by five obstetricians to determine whether information could be collected an analyzed to identify common predisposing factors to claims and to suggest preventative measures. The data suggests these cases contain common easily identified obstetric risk factors, most of which occurred in labor and delivery (66%). Fifty-four percent of the risks were recognized, 32% correctly managed, and a high percentage of risks were considered by the reviewers to be directly related to the obstetric outcome leading to the claim (66%). The authors feel obstetric closed claims can be studied and suggestions made to aid obstetricians in providing care. Identification of common obstetric risks and correct management of these risks is poor in these cases. Recognition and management guidelines are imperative in ensuring good obstetric outcome. These two physician-controlled factors played important parts in the majority of cases reviewed. It would appear from this study that obstetric malpractice closed claims are amenable to study; physicians and their patients would benefit from better data collection systems to identify risks in individual pregnancies; physicians need readily available resources to aid their management of patients; only through modification of physician behavior can suits be avoided.

Delivery, Obstetric↗
PubMed1985

Intestinal giardiasis associated with ocular inflammation.

A relationship between intestinal giardiasis and ocular inflammatory conditions may result in significant vision loss. The parasitic infestation may not produce gastrointestinal symptoms and since early eradication of the parasite may prevent permanent visual loss, it is important that gastroenterologists as well as ophthalmologists be aware of this association.

Adult↗
PubMed1984

A tissue-specific transcription enhancer element in the human immunoglobulin lambda light chain locus.

An 8.0-kb EcoRI fragment of the human immunoglobulin (Ig) lambda light chain locus carrying the Ke-Oz- and Ke-Oz+ constant region genes and flanking sequences was studied for the presence of a transcriptional enhancer. Two types of assays were used. In the first, we measured the ability of recombinant plasmids carrying the 8.0-kb Ig fragment covalently linked to the aminoglycoside phosphotransferase (aph) gene to transform mouse myeloma or mouse fibroblast cells to geneticin resistance. In the second, we used RNA spot and Northern blot hybridization analyses to determine the relative levels of aph specific RNA transiently expressed after DNA transfection. In fibroblast cells, the transformation frequencies were independent of the presence of the Ig fragment in the vector and there was no difference in the level of transient expression of the aph gene. In myeloma cells, the Ig fragment enhanced at least 10-fold both the number of transformants and the level of aph gene expression over that obtained with vector alone. These results indicate the presence of a tissue-specific transcriptional enhancer in the 8.0-kb EcoRI fragment of the human Ig C lambda locus.

Animals↗
PubMed1984

The isolation of a human Ig V lambda gene from a recombinant library of chromosome 22 and estimation of its copy number.

We report the first isolation and characterisation of a human Ig V lambda gene. The gene was isolated from a recombinant phage library of human chromosome 22 using a mouse Ig lambda cDNA as probe. DNA sequence analysis predicts a short leader peptide interrupted by an intron of 88 nucleotides, and a mature polypeptide of 96-97 amino acids which shares 61% homology with mouse V lambda I chains. Comparison with the amino acid sequence of known human lambda chains of all six subgroups shows agreement at 22/25 low variance positions. However the maximum homology with human chains is 49%, so we conclude that this sequence represents a new IgV lambda subgroup. The coding region is followed by the conserved heptamer, CACAGTG, and nonamer, ACATAAACC, sequences which have been implicated in V-J segment recombination. This gene has the hallmarks of an active V lambda gene including recently identified transcriptional controlling sequences. Probing genomic DNA with the subcloned V lambda gene detects a family of about 10 cross hybridizing members at low stringency and 2 at high stringency. There is limited polymorphism of the V lambda locus.

Base Sequence↗