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Biomedical subjects

M Bard

Publications and source records attributed to M Bard.

At least 19 recordsLinked to original sources
PubMed1992

The need for multidisciplinary training in counseling the medically ill. Report of the training committee of the Linda Pollin Foundation.

Training for medical counselors requires that medicine and psychiatry give up the position that counseling is only a negligible offshoot that almost any professional can readily do. Instead, counseling can be considered a generic concept that covers a wide variety of interventions designed to help patients cope with the complications and consequences of their chronic illness. This report outlines the principles and scope of training for consideration in the area of counseling the medically ill and reviews the current status of training programs in the fields of psychiatry, psychology, social work, and nursing. Recommendations are made for future directions, including role clarification for disciplines, building a credible research base, provision of guidelines and possible accreditation, and incorporating medical counseling into training fellowships.

Chronic Disease↗
PubMed1991

High-performance affinity chromatography of messenger RNA.

A 50-mer of thymidylic acid, (dT)50, was coupled to silica inside prepacked columns using the N-hydroxysuccinimide chemistry. The resulting (dT)50-silica columns were used to resolve oligomers of adenylic acid, (dA)19-24, and to separate poly(A) mRNA (messenger RNA) from Saccharomyces. Oligomers which differed in length by a single nucleotide base were readily resolved. Using either (dT)50- or (dT)18-silica, poly(A) mRNA could be purified in as little as 8 min. The poly(A) mRNA isolated appeared to be full length and could be used directly for T4 RNA ligase and RNAse A and T1 enzymatic reactions. The (dT)50-silica column was used to fractionate total poly(A) mRNA by tail length. While the separation was primarily due to poly(A) tail length, most fractions appeared to contain multiple tail lengths. Whether this represents an intrinsic feature of the RNA or a limitation of the method is discussed. These studies show that polynucleotides in the kilobase size range can be separated rapidly and with good resolution on DNA-silica.

Chemical Precipitation↗
PubMed1991

Cloning, disruption and sequence of the gene encoding yeast C-5 sterol desaturase.

The ERG3 gene from Saccharomyces cerevisiae has been cloned by complementation of an erg3-2 mutation. ERG3 is the putative gene encoding the C-5 sterol desaturase required for ergosterol biosynthesis. The functional gene has been localized on a 2.5-kb HindIII-BamHI fragment containing an open reading frame comprising 365 amino acids. Gene disruption resulting from a deletion/substitution demonstrates that ERG3 is not essential for cell viability or the sparking function.

Amino Acid Sequence↗
PubMed1991

Quality of life research in oncology. Past achievements and future priorities.

The status of quality of life research in oncology is assessed, and priorities for future research with regard to conceptual and theoretical developments, focus and content of research, research designs and practical strategies for research implementation, and transferring information to clinical practice and medical policy decision-making are identified. There is general agreement that quality of life is a subjective and multidimensional construct, yet comprehensive theoretical models have not been developed and applied fully. We recommend that future research be based on conceptual models that explicate the interrelationships among quality of life domains throughout the stages of cancer care. These models, and the longitudinal research that follows from them, should attend specifically to cross-class and cross-cultural issues to avoid overgeneralization from theory and research that are based largely on the views of the majority culture. We encourage the inclusion of this theory-based quality of life assessment as a standard component of clinical trials. Success in this endeavor will require additional standardization of quality of life measures for use across a range of cancer patient populations, including the development of age-specific norms and instruments designed to assess the entire family system.

Humans↗
PubMed1991

Cloning and disruption of the yeast C-8 sterol isomerase gene.

The yeast ERG2 gene codes for the C-8 sterol isomerase, an enzyme required for the isomerization of the delta 8 double bond to the delta 7 position in ergosterol biosynthesis. The ERG2 gene was cloned by complementation of a C-8 sterol isomerase mutant strain (erg2). The complementing region of DNA required to restore ergosterol synthesis to erg2 was limited to a 1.0 kb StuI-BglII fragment. In order to determine whether the ERG2 gene was essential for yeast viability, a LEU2 gene was inserted into the NdeI site (made blunt) of this 1.0 kb fragment. Transformation of a wild type diploid strain with the ERG2 substituted DNA resulted in the generation of viable haploids containing the erg2 null allele (erg2-4::Leu2). These results suggest that the C-8 sterol isomerase activity is not essential for yeast cell viability. This disruption represents the second ergosterol biosynthetic gene in the distal portion of the pathway to be disrupted without adversely affecting cell viability.

Cloning, Molecular↗
PubMed1990

High-performance affinity chromatography of DNA.

The octadecamer of thymidylic acid, (dT)18, was synthesized with a primary amino group on the 5'-terminal phosphate and this was covalently coupled to 300 A pore macroporous silica. Coupling was performed inside a prepacked column to an activated N-hydroxysuccinimidyl ester silica. The (dT)18-silica column successfully separates mixtures of adenine oligomers differing in length by one nucleotide. The dependence upon salt concentration, temperature and length for elution of oligonucleotides was determined. Methods were also developed to selectively elute such columns using either salt or temperature gradients.

Cation Exchange Resins↗
PubMed1990

Azole susceptibility and hyphal formation in a cytochrome P-450-deficient mutant of Candida albicans.

A cytochrome P-450-deficient mutant of Candida albicans, strain D10, was employed to study the mode of action of imidazole antifungal agents. This mutant accumulates exclusively 14-alpha-methylsterols, resulting in a sterol profile which mimics that of azole-treated wild-type strains. Since the widely accepted primary effect of imidazoles is the inhibition of cytochrome P-450-mediated demethylation of the ergosterol precursor lanosterol, strain D10 and its wild-type revertant, strain D10R, were grown in the presence of concentrations of clotrimazole, miconazole, and ketoconazole known to inhibit demethylation. The growth of strain D10 was unaffected by these antifungal agents, while that of strain D10R was significantly reduced. At higher azole concentrations (which are known to exert a direct, disruptive action on the cell membrane), the growth of both strains was immediately and completely inhibited by clotrimazole and miconazole. Ketoconazole was membrane disruptive only for strain D10; this is the first report of a direct membrane effect for this drug. Because hyphal formation has been implicated in the pathogenesis of C. albicans and because it has been shown to be inhibited by azoles, the hypha-forming capability of strain D10 was examined. Strain D10 was shown to be seriously defective in hyphal formation, suggesting that this function may be dependent on the 14-alpha-demethylation of lanosterol. The results of this study suggest that inhibition of lanosterol demethylation per se is neither fungicidal nor fungistatic, although the growth rate is reduced. In addition, the substitution of 14-alpha-methylsterols for ergosterol results in defective hyphal formation and in a cell that is more susceptible to membrane-active agents such as ketoconazole.

Azoles↗
PubMed1990

Synovial membrane: percutaneous biopsy.

With use of fluoroscopy, new techniques of percutaneous synovial biopsy (PSB) of large joints of limbs (other than the knee) were developed. PSB was performed on outpatients with the use of local anesthesia. Eighty-four biopsies (hip, 57; shoulder, 10; elbow, six; wrist, five; and ankle, six) were performed. With experience, modifications evolved in the PSB technique. The main technical refinements were use of a Tru-Cut needle introduced through a Jamshidi trephine needle, placement of the cutting window parallel to the anterior aspect of the joint, and selection of an optimal approach and biopsy site. With these improvements, the success rate for obtaining synovial membrane was raised from 48% to 81%. No complications were encountered.

Adolescent↗
PubMed1989

The yeast gene ERG6 is required for normal membrane function but is not essential for biosynthesis of the cell-cycle-sparking sterol.

In Saccharomyces cerevisiae, methylation of the principal membrane sterol at C-24 produces the C-28 methyl group specific to ergosterol and represents one of the few structural differences between ergosterol and cholesterol. C-28 in S. cerevisiae has been suggested to be essential for the sparking function (W. J. Pinto and W. R. Nes, J. Biol. Chem. 258:4472-4476, 1983), a cell cycle event that may be required to enter G1 (C. Dahl, H.-P. Biemann, and J. Dahl, Proc. Natl. Acad. Sci. USA 84:4012-4016, 1987). The sterol biosynthetic pathway in S. cerevisiae was genetically altered to assess the functional role of the C-28 methyl group of ergosterol. ERG6, the putative structural gene for S-adenosylmethionine: delta 24-methyltransferase, which catalyzes C-24 methylation, was cloned, and haploid strains containing erg6 null alleles (erg6 delta 1 and erg6 delta ::LEU2) were generated. Although erg6 delta cells are unable to methylate ergosterol precursors at C-24, they exhibit normal vegatative growth, suggesting that C-28 sterols are not essential in S. cerevisiae. However, erg6 delta cells exhibit pleiotropic phenotypes that include defective conjugation, hypersensitivity to cycloheximide, resistance to nystatin, a severely diminished capacity for genetic transformation, and defective tryptophan uptake. These phenotypes reflect the role of ergosterol as a regulator of membrane permeability and fluidity. Genetic mapping experiments revealed that ERG6 is located on chromosome XIII, tightly linked to sec59.

Biological Transport↗
PubMed1979

ESR determination of membrane order parameter in yeast sterol mutants.

ESR investigations designed to determine membrane order parameter in sterol mutants of Saccharomyces cerevisiae were conducted using the membrane probe, 5-doxyl stearic acid. These mutants are blocked in the ergosterol biosynthetic pathway and thus do not synthesize ergosterol, the end product sterol. They do not require exogenous ergosterol for growth and, therefore, incorporate ergosterol biosynthetic intermediates in their membrane. Increasing order parameter is reflective of an increase in membrane rigidity. Single mutants involving B-ring delta 8 leads to delta 7 isomerization (erg 2) and C-24 methylation (erg 6) showed greater membrane rigidity than wild-type during exponential growth. A double mutant containing both lesions (erg 6/2) showed an even greater degree of membrane rigidity. During stationary phase the order of decreasing membrane rigidity was erg 6 greater than erg 6/2 greater than erg 2 = wild-type. The increased membrane order parameter was attributed to the presence of substituted sterols rather than increased sterol content or altered fatty acid synthesis.

Cell Membrane↗
PubMed1979

[Tomodensitometry and spinal pathology].

The authors describe the possibilities and the limitations of the "scanner" in spinal pathology. Use of the third dimension and the certainty of absolute measurements, make this a very interesting method that can be applied to several areas of spinal pathology, especially traumatology and detection of primary and secondary tumors. It seems that this technique may be used in particular in the study of canal stenoses. There are future possibilities in view for segmentary densitometry, which gives better results than overall scintigraphy, especially in locating metastases. At present, studies are underway using contrast solution in order to study the possibilities of interpreting the content-container relationship.

Humans↗
PubMed1979

[Postoperative sciatica from epidural fibrosis and lumbar arachnoiditis. Results of 38 repeat operations].

Lumbar epiduro-arachnoiditis is a well-known complication of surgery of the intervertebral disc. The epidural fibrous scar is the normal outcome of inflammatory activity secondary to the mechanical tissue disturbance resulting from surgery. In certain individuals, perhaps genetically predisposed as excessive quantity of fibrous tissue is deposited in the epi and/or nitradural space. This abnormal situation, comparable to cheloid cutaneous scars, is perhaps at the origin of the clinical symptoms. The authors report the clinical and radiological signs observed in 38 patients having had at least one operation for discal hernia, and who underwent further operations in the aim of freeing the roots and the dural sack from fibrous compression. Results of excision of the epidural "cheloid" were good in 13 cases, and average in 8 others. There was a complete failure in 17 other patients. Three explanations were offered to explain the frequency of the failures: 1) formation of a new cheloid, 2) difficulty of neurolysis of the arachnoiditis, 3) possibility of intrinsic lesions of the nerve associated with the epiduro-arachnoiditis.

Adult↗