Biomedical subjects

M Carlson

Publications and source records attributed to M Carlson.

At least 163 records · Page 9Linked to original sources

PubMed1990

Decline in respiratory function and experience with long-term assisted ventilation in advanced Duchenne's muscular dystrophy.

We present 17 patients with advanced DMD who required long-term assisted ventilation. Eleven patients used part-time assisted ventilation. Five of the patients received BV and/or M-IPPV or N-IPPV between two and nine years before requiring full-time T-IPPV, while six others initially used part-time T-IPPV. One patient used all three modes before requiring full-time T-IPPV. Mean (+/- SD) FVC and rebreathe PCO2 at the outset of assisted ventilation were 0.62 +/- 0.20 L and 47.4 +/- 7.5 mm Hg, respectively. Clinical features were divided between symptoms suggesting respiratory muscle fatigue and sleep-related disordered breathing. We found that, while useful in early respiratory insufficiency, BV is associated with recurrent aspiration. In our experience, N-IPPV offers the safest and most convenient form of noninvasive ventilation. When the VC has decreased to about 300 ml, most patients will require full-time ventilation; T-IPPV is advised to provide airway access to suction secretions.

Adolescent↗

PubMed1989

Determination of thymol in halothane anaesthetic preparations by high-performance liquid chromatography.

A high-performance liquid chromatographic (HPLC) procedure has been developed for the isolation and quantification of thymol, a stabilizing agent present in halothane anaesthetic preparations. The method offers improvements in specificity and simplicity with respect to a current official procedure for thymol in halothane. Results for commercial preparations obtained by the proposed procedure demonstrate excellent precision and accuracy with RSD values for replicate analysis ranging from 0.11 to 0.74% and recoveries via fortification from 99.6 to 100.1%. The HPLC method was compared to compendial procedures for thymol bulk substance and halothane products. Chromatographic separation of other related phenolic preservatives used in pharmaceuticals suggests a more extensive application of the proposed procedure.

Chromatography, High Pressure Liquid↗

PubMed1989

Mutational analysis of the Saccharomyces cerevisiae SNF1 protein kinase and evidence for functional interaction with the SNF4 protein.

The SNF1 gene of Saccharomyces cerevisiae encodes a protein-serine/threonine kinase that is required for derepression of gene expression in response to glucose limitation. We present evidence that the protein kinase activity is essential for SNF1 function: substitution of Arg for Lys in the putative ATP-binding site results in a mutant phenotype. A polyhistidine tract near the N terminus was found to be dispensable. Deletion of the large region C terminal to the kinase domain only partially impaired SNF1 function, causing expression of invertase to be somewhat reduced but still glucose repressible. The function of the SNF4 gene, another component of the regulatory system, was required for maximal in vitro activity of the SNF1 protein kinase. Increased SNF1 gene dosage partially alleviated the requirement for SNF4. C-terminal deletions of SNF1 also reduced dependence on SNF4. Our findings suggest that SNF4 acts as a positive effector of the kinase but does not serve a regulatory function in signaling glucose availability.

Adenosine Triphosphate↗

PubMed1989

Molecular analysis of the SNF4 gene of Saccharomyces cerevisiae: evidence for physical association of the SNF4 protein with the SNF1 protein kinase.

The SNF4 gene is required for expression of glucose-repressible genes in response to glucose deprivation in Saccharomyces cerevisiae. Previous evidence suggested that SNF4 is functionally related to SNF1, another essential gene in this global regulatory system that encodes a protein kinase. Increased SNF1 gene dosage partially compensates for a mutation in SNF4, and the SNF4 function is required for maximal SNF1 protein kinase activity in vitro. We have cloned SNF4 and identified its 1.2-kilobase RNA, which is not regulated by glucose repression. A 36-kilodalton SNF4 protein is predicted from the nucleotide sequence. Disruption of the chromosomal SNF4 locus revealed that the requirement for SNF4 function is less stringent at low temperature (23 degrees C). A bifunctional SNF4-lacZ gene fusion that includes almost the entire SNF4 coding sequence was constructed. The fusion protein was shown by immunofluorescence microscopy to be distributed throughout the cell, with partial localization to the nucleus. The SNF4-beta-galactosidase protein coimmunoprecipitated with the SNF1 protein kinase, thus providing evidence for the physical association of the two proteins.

Amino Acid Sequence↗

PubMed1989

Localization of the genetic defect in multiple endocrine neoplasia type 1 within a small region of chromosome 11.

Multiple endocrine neoplasia type I (MEN-1), a Mendelian disorder with an autosomal dominant mode of inheritance, causes hyperplasia in the parathyroid glands and hyperplasia or neoplasm in the anterior pituitary gland and/or the pancreatic islets. The genetic defect responsible for MEN-1 in three families was recently mapped to the long arm of chromosome II by linkage between the MEN-1 locus and the gene for skeletal muscle glycogen phosphorylase (PYGM) at 11q13. We have constructed a genetic linkage map of seven markers in the vicinity of the MEN-1 locus that has allowed us to map more precisely the gene associated with MEN-1; the target region has been narrowed to about 12 cM. The closely linked markers will be useful also for identification of likely carriers in families in which an allele responsible for MEN-1 segregates.

Chromosome Mapping↗

PubMed1989

Vertebral bone density in Scheuermann disease.

The densities of the trabecular bone of two or three lumbar vertebral bodies in twenty adolescents, twelve to eighteen years old, who had Scheuermann disease were measured by quantitative computed tomography. These densities were then compared with those for the same vertebrae of twenty age, sex, and race-matched adolescents who were examined by computed tomography because of trauma. The same scanner and phantom were used in all examinations. Both the adolescents who had Scheuermann disease and the control patients were in good health before the quantitative computed-tomography examination and had not been taking any medications. The density of the trabecular bone density in the patients who had Scheuermann disease was not significantly different (p = 0.28) from that in the controls. There also were no significant differences between the patients and the controls with regard to height, weight, surface area, or body-mass index.

Adolescent↗

PubMed1988