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Biomedical subjects

L Rogers

Publications and source records attributed to L Rogers.

At least 73 records · Page 4Linked to original sources
PubMed1987

Diesters of 3-hydroxy fatty acids produced by the uropygial glands of female mallards uniquely during the mating season.

The uropygial gland secretions produced by female mallards (Anas platyrhynchos) throughout the year were analyzed by thin-layer chromatography and combined gas-liquid chromatography and mass spectrometry. Most of the year, the secretion was composed of wax esters. With the beginning of the mating season in the middle of March, a polar component appeared which became the dominant and sole component of the secretion through April and May and as the mating season ended in June, wax esters became the sole component of the secretion. The polar components were identified to be diesters of n-C8, n-C10, and n-C12 3-hydroxy acids with n-C16 and n-C18 alcohols and n-C6 to C16 even chain acids. Immediately after the diester-producing period the female uropygial glands produced very long chain wax esters composed of fatty acids longer than C12. By the end of August, shorter chain wax esters composed of C6 and C12 acids became the dominant components of the secretion and this composition, previously considered characteristic of mallards, remained constant until March. The observed disappearance of the short chain waxes during the postnuptial period is similar to that in males. The dramatic changes in the composition of the uropygial glands similar to those observed in the female mallards during the mating season have not yet been observed in any other species.

Alcohols↗
PubMed1986

Men, women, and religion: stress within leadership roles.

Stress in religious leaders was investigated by administering to 250 priests, ministers, seminarians, nuns, and brothers the specially devised Religion and Stress Questionnaire and the Osipow and Spokane Occupational Environment Scales, Personal Strain Questionnaire, and Personal Resources Questionnaire. In-depth interviews were also conducted with 10% of the subjects. Religious leaders experienced lower overall occupational stress and personal strain and evidenced more personal resources than did the normative population. ANOVAs showed ministers to have the highest overall occupational environment stress and vocational strain and next to the lowest scores in overall personal resources of the five groups of religious professionals. In terms of sensitivity to the stress that women in seminary and ministry experience, male and female seminarians and ministers were most aware of these issues, with priests (males only), nuns, and then brothers (in descending order) sensitive to these concerns.

Adaptation, Psychological↗
PubMed1986

Leptomeningeal metastasis from supratentorial malignant gliomas.

The clinical and diagnostic findings in 13 patients with leptomeningeal metastasis from supratentorial malignant gliomas are reported. Criteria for inclusion in this study were positive myelographic examination, positive cerebrospinal fluid cytology on two or more samples, or evidence of leptomeningeal seeding at autopsy. Eight patients had premortem symptoms of leptomeningeal metastasis, with the diagnosis confirmed during life in 5 patients. Average survival after the onset of symptoms was 3 months (range, 1 to 5 months). Comparison of the autopsied group with 10 concurrent autopsied patients without leptomeningeal gliomatosis did not reveal any significant differences in age, but leptomeningeal gliomatosis was more prevalent in patients with longer postoperative survival. Leptomeningeal involvement at autopsy was more extensive in symptomatic patients. Cerebrospinal fluid examination often gave nondiagnostic or nonspecific results. Computed tomography of the brain showed evidence of ventriculomegaly, periventricular contrast enhancement, or multifocal tumor involvement in every case. Iophendylate myelography was the most reliable diagnostic tool and established the diagnosis whenever performed. The natural history and clinical significance of leptomeningeal metastasis from supratentorial malignant gliomas are discussed.

Adolescent↗
PubMed1986

Acyl-CoA reductase and acyl-CoA: fatty alcohol acyl transferase in the microsomal preparation from the bovine meibomian gland.

Biosynthesis of wax esters, one of the two major products of the meibomian gland, was found to be catalyzed mainly by the microsomes of the bovine meibomian gland. The microsomal preparation catalyzed hexadecanoyl-CoA reduction to hexadecanol without any accumulation of the aldehyde intermediate. Maximal rates of reduction occurred at pH 6.5 and required both NADH and NADPH; the latter alone gave considerable rates whereas NADH alone was ineffective. Exogenous hexadecanal reduction catalyzed by the same preparation showed a preference for NADH. The hexadecanoyl-CoA saturation pattern was slightly sigmoidal and concentrations higher than 125 microM inhibited reduction. The fatty alcohol generated from hexadecanoyl-CoA was found as free alcohol and as wax esters. Esterification of hexadecanol to wax esters catalyzed by the meibomian gland microsomal preparation required exogenous acyl-CoA or ATP and CoA and was not affected by exogenous cholesterol. Maximal rates of esterification were observed at neutral pH. Hexadecanoyl-CoA concentrations higher than 125 microM inhibited esterification. Hexadecanol showed a typical substrate saturation pattern with an apparent Km of 125 microM. Radio gas-liquid chromatography showed that, in the presence of exogenous hexadecanoyl-CoA, hexadecanol gave hexadecyl hexadecanoate whereas in the presence of ATP and CoA both C16 and C18 endogenous acids were used to esterify the alcohol. Consistent with the composition of the meibomian gland secretion, exogenous acyl-CoA longer than C14 and shorter than C20 gave maximal rates of esterification of hexadecanol.

Aldehyde Oxidoreductases↗
PubMed1985

Cloning and sequencing of the cDNA for S-acyl fatty acid synthase thioesterase from the uropygial gland of mallard duck.

In vitro translation of poly(A)+ RNA from the uropygial glands of mallard ducks (Anas platyrhynchos) generated a 29-kDa protein which cross-reacted with rabbit antibodies prepared against S-acyl fatty acid synthase thioesterase (Kolattukudy, P. E., Rogers, L., and Flurkey, W. (1985) J. Biol. Chem., 260, 10789-10793). A poly(A)+ RNA fraction enriched in this thioesterase mRNA, isolated by sucrose density gradient centrifugation, was used to prepare cDNA which was cloned in Escherichia coli using the plasmid pUC9. Using hybrid-selected translation and colony hybridization, 17 clones were selected which contained the cDNA for S-acyl fatty acid synthase thioesterase. Northern blot analysis showed that the mature mRNA for this thioesterase contained 1350 nucleotides whereas the cloned cDNA inserts contained 1150-1200 base pairs. Five of the 6 clones tested for 5'-sequence had identical sequences, and the three tested for 3'-end showed the same sequence with poly(A) tails. Two clones, pTE1 and pTE3, representing nearly the full length of mRNA, were selected for sequencing. Maxam-Gilbert and Sanger dideoxy chain termination methods were used on the cloned cDNA and on restriction fragments subcloned in M13 in order to determine the complete nucleotide sequence of the cloned cDNA. The nucleotide sequence showed an open reading frame coding for a peptide of 28.8 kDa. Two peptides isolated from the tryptic digest of the thioesterase purified from the gland showed amino acid sequences which matched with two segments of the sequence deduced from the nucleotide sequence. Another segment containing a serine residue showed an amino acid sequence homologous to the active serine-containing segment of the thioesterase domain of fatty acid synthase. Thus, the clones represent cDNA for S-acyl fatty acid synthase thioesterase. The present results constitute the first case of a complete sequence of a thioesterase.

Amino Acid Sequence↗
PubMed1985

Suppression of a thioesterase gene expression and the disappearance of short chain fatty acids in the preen gland of the mallard duck during eclipse, the period following postnuptial molt.

Wax esters of short chain acids (monomethyl-C6) constitute the major products of the uropygial gland of mallard ducks. During eclipse, the period (June and July) immediately following postnuptial molt, the production of short chain acyl groups is severely curtailed and longer chain acyl groups become the dominant components; after this period the composition reverts. These changes in composition were accompanied by corresponding changes in the level of S-acyl fatty acid synthase thioesterase activity, and the level of the immunologically detectable amount of this enzyme. In vitro translation of the poly(A)+ RNA from the gland produced a 30-kDa protein which cross-reacted with rabbit antibodies prepared against this enzyme. The level of translatable mRNA for the thioesterase in the gland dramatically decreased as the birds went into eclipse and all of these changes reverted when the eclipse period was over. These results strongly suggest that the thioesterase is involved in the production of the short chain fatty acids in vivo and that during eclipse the expression of the thioesterase gene is suppressed.

Aging↗
PubMed1985

Absorption of delayed-release prednisolone in ulcerative colitis and Crohn's disease.

The absorption and urinary excretion of [3H]prednisolone after oral ingestion was examined using hard gelatin capsules with and without a coating of Eudragit-S which delayed release of the contents. In 6 patients with ulcerative colitis absorption was delayed until the preparation reached the colon but the total absorption was unchanged. In 6 patients with Crohn's disease and ileal strictures the preparation broke proximal to the stricture and absorption was delayed until this occurred (within 4-12 h). In 5 patients with Crohn's disease and intestinal resections the capsules broke unreliably.

Adult↗
PubMed1985

Disappearance of short chain acids from the preen gland wax of male mallard ducks during eclipse.

Wax esters constitute the major products of the uropygial glands of male mallard ducks (Anas platyrhynchos). Combined gas-liquid chromatography and mass spectrometry of the acyl and alcohol portions of the wax ester revealed dramatic seasonal variation. Of the total of nearly 100 compounds detected in the acyl portion, more than 90 were identified as n-, monomethyl-, dimethyl-, and trimethyl-C6 to C20 acids. The major components were 2-methyl- and 4-methyl C6 acids which constituted nearly 75% of the total acids during most of the year. As the birds went through the post-nuptial molt into eclipse, these short chain acids decreased to only 4% of the total acids. Fatty acids longer than C12 became the major components during the summer months when the birds were in eclipse and by fall the characteristic shorter branched acids reappeared as the dominant components. Fatty alcohols did not undergo such dramatic changes. This is the first report of biochemical changes that occur during eclipse.

Animals↗
PubMed1984

Biosynthesis of alkanes by particulate and solubilized enzyme preparations from pea leaves (Pisum sativum).

Enzymatic activity responsible for the conversion of fatty acids to alkanes catalyzed by pea leaf homogenate was found to be mainly in the microsomal fraction. This particulate preparation catalyzed alkane formation from n-C18, n-C22, and n-C24 acids at rates comparable to that observed with n-C32 acid with O2 and ascorbate as required cofactors. In each case the major alkane contained two carbon atoms less than the precursor acid. Since the preparation also catalyzed alpha-oxidation, it was suspected that some alpha-oxidation intermediate, with one less carbon atom than the substrate acid, might lose another carbon to generate the alkane. Thin-layer and radio-gas-liquid chromatographic analysis of the products generated from [U-14C]stearic acid by the particulate preparation after different periods of incubation showed that, at all time periods, alpha-hydroxy C18 acid, C17 aldehyde, and C17 acid were the major products. Since C16 alkane was the major product even after short periods of reaction, the C17 aldehyde might have been the immediate precursor of the alkane. Exogenous labeled C18 and C24 aldehyde were converted to alkanes. The alkane-synthesizing activity was solubilized from the microsomal preparation using Triton X-100. The solubilized preparation was retarded in a Sepharose 6-B column, but the hydrocarbon-forming activity was not resolved from alpha-oxidation. The solubilized preparation produced alkane with two carbon atoms less than the parent acid in a time- and protein-dependent manner. The soluble preparation also required O2 and ascorbate and, like the microsomal preparation, was inhibited by dithioerythritol and metal ion chelating agents.

Alkanes↗
PubMed1984

Purification of S-acyl fatty acid synthase thioester hydrolase by affinity chromatography with fatty acid synthase attached to Sepharose.

S-Acyl fatty acid synthase thioester hydrolase, the enzyme responsible for release of short-chain fatty acids from fatty acid synthase, was purified to homogeneity in 50-60% yield by a procedure involving affinity chromatography with fatty acid synthase as the affinity ligand attached to Sepharose. This procedure gave a 10- to 12-fold increase in yield over the previously available method.

Animals↗
PubMed1983

Psychosocial reactions to the diagnosis of gynecologic cancer.

Data are presented on the psychosocial impact of gynecologic cancer derived from both a structured interview and self-report scales administered to 60 women newly diagnosed with cervical, uterine, and ovarian malignancies. Findings show that such women experience mild to moderate symptoms of depression and anxiety, as well as impairment of vocational, domestic, and sexual functioning. The women with cancer reported significantly fewer symptoms of depression and social impairment than acutely depressed women without cancer. The women studied also demonstrated significantly more symptoms of depression and social impairment than women without psychiatric disease from randomly selected community samples. The symptoms of depression experienced by women with ovarian cancer, women receiving triple-agent chemotherapy and women with poorly differentiated tumors of the endometrium and ovary approached the level of acute symptoms typically reported by women entering outpatient psychiatric clinics. These observations should enhance the understanding of these problems among gynecologists and other health care providers in offering appropriate psychosocial support for women with gynecologic cancer.

Adolescent↗
PubMed1982

Population genetic models in the study of aging and longevity in a Mennonite community.

This is a preliminary report on a 3-year multidisciplinary study of aging among historically and genetically related Mennonite congregations in Kansas and Nebraska. Three aspects of longevity and aging are examined: (1) the relationship of heterozygosity to survivorship using 8 genetic blood group loci, (2) changes in taste sensitivity with age using 14 dilutions of PTC; and (3) life span correlations among parents and offspring during a 100 year period. Heterozygosity was found to be independent of survivorship. No diminution in taste sensitivity to PTC was found with increasing age although a significant difference in PTC taste thresholds was found between males and females. No relationship was found between nontasters and individuals with a history of thyroid disease. Mother's life span was found to correlate more closely with daughter than any other familial correlation.

Adolescent↗