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Biomedical subjects

L Taylor

Publications and source records attributed to L Taylor.

At least 271 records · Page 15Linked to original sources
PubMed1982

Suitability of frozen and lyophilized reference sera for cholesterol and triglyceride determinations.

Observations on the suitability of frozen and lyophilized reference sera stored at -20 degrees C are presented. These sera, intended for use as controls for both cholesterol and triglyceride determinations, covered ranges for cholesterols from 4 to 8 mmol/l and for triglyceride from 0.7 to 2.4 mmol/L. We observed no change in cholesterol or triglyceride concentration in either the frozen or lyophilized forms of serum during almost 5 years of storage. The suitability of these materials for cholesterol and triglyceride determinations is demonstrated by representative methods. Our results show that lyophilized reference sera can be shipped unprotected by dry ice without any effect on cholesterol or triglyceride concentration. Although the total cholesterol concentration was unchanged with storage, changes did occur in the lipoproteins carrying these lipid constituents.

Blood Preservation↗
PubMed1982

Ca2+- and calmodulin-dependent protein phosphorylation in rat lacrimal gland.

Ca2+, in homogenized lacrimal glands, enhanced phosphorylation of several peptides. Phosphorylation of two of these peptides was further stimulated by addition of the Ca2+-binding protein calmodulin and decreased by trifluoperazine, an inhibitor of Ca2+--calmodulin-dependent activity. Thus, Ca2+--calmodulin-dependent protein kinases and their substrates are present in lacrimal gland and could have an important role in lacrimal-gland function.

Animals↗
PubMed1982

Promoter mapping and DNA sequencing of the F plasmid transfer genes traM and traJ.

The nucleotide sequence of the DNA encoding the traM, finP and the promoter proximal segment of the traJ gene of the F plasmid has been determined. The predicted amino acid sequence for the traM protein shows that this inner membrane protein contains no signal sequence. The promoters for both the traM and traJ genes have been mapped by in vitro transcription and nuclease S1 protection experiments. No unambiguous location can be assigned to the finP gene but all candidates, if translated, would encode small proteins of between 24 and 52 amino acids.

Amino Acid Sequence↗
PubMed1982

Parent and child causal attributions during clinical interviews.

Attributions made by children and their parents for the cause of the child's clinical problem were monitored during assessment interviews. Results support previously observed differences obtained through questionnaires, with parents making more attributions than their children to characteristics of the child. This pattern was affected by variations in interview format. Parents and children differed in the locus of their attributions when interviewed individually, but these differences were not present when families were interviewed with both parents and children present. Implications for the methodology of attribution research with child-clinical populations are highlighted.

Adolescent↗
PubMed1982

Prevalence and treatment of learning problems in upper and lower income areas.

In a telephone survey, a lower incidence of learning problems, help received, and perceived effectiveness was reported in lower income areas. More upper income respondents reported receiving formal diagnoses and treatment. Possible discrepancies between official and resident reports of learning problems, the apparent need for additional services by both income groups, and the likelihood that residents are overestimating effectiveness and prognosis are discussed.

California↗
PubMed1982

The effect of ascorbate, hydroperoxides, and bradykinin on prostaglandin production by corneal and lens cells.

Epithelial cells from the rabbit cornea, fibroblasts from the rabbit and calf cornea, and calf lens epithelial cells were placed in individual cultures. Prostaglandin (PG) synthesis by these cell types was determined. Lens epithelial cells produced no detectable PGs under basal conditions. Corneal fibroblasts primarily produced PGE2, while epithelial cells primarily produced thromboxane A2. PG production by corneal fibroblasts was highly responsive to bradykinin, ascorbic acid, hydrogen peroxide, and t-butyl hydroperoxide, an organic peroxide. Quantitative differences in PG production between the rabbit and calf corneal fibroblasts were observed. Our results suggest that the reported therapeutic actions of ascorbic acid in the eye may, at least in part, be mediated through the PGs. Our results also support the proposed role for hydroperoxides in the control of PG synthesis.

Animals↗
PubMed1981

Low lipid level reference sera with human serum matrix.

We describe a simple procedure for preparing low lipid level reference sera containing concentrations of nonlipid components similar to the concentrations in human serum. A portion of human serum is delipidized with colloidal silicic acid, and the delipidated serum, in selected proportions, is combined with the native serum. These reference materials can be used as internal or external quality controls in conjunction with low total cholesterol and low high-density lipoprotein (HDL) cholesterol determinations in serum or plasma. They can also be used as controls with low triglyceride determinations.

Blood Preservation↗
PubMed1981

Affective behavior in patients with localized cortical excisions: role of lesion site and side.

The perception of emotion in verbal and facial expression, and the spontaneous production of conversational speech were studied in patients with unilateral focal excisions of frontal, temporal, or parieto-occipital cortex. Lesions of the left hemisphere impaired the matching of verbal descriptions to appropriate verbal categories of emotional states, whereas with lesions of the right hemisphere, the matching of different faces displaying similar emotional states was impaired. The effects of lesions of both left and right hemisphere occurred regardless of the locus of the lesion. On the other hand, frontal-lobe lesions had differential effects upon unsolicited talking; lesions of the left frontal lobe virtually abolished this behavior, whereas lesions of the right frontal lobe produced excessive talking. These data suggest that the nature of the behavioral stimulus as well as the locus and side of damage must be considered in the study of the neural basis of affective behavior.

Affect↗
PubMed1981

Preparation of reference sera with desired levels of cholesterol and triglyceride.

Simple methods for isolating cholesterol-rich protein fraction from human serum and triglyceride-rich fraction from hen egg yolk are presented. The isolated fractions are combined separately with small volumes of human serum in order to stabilize concentrated cholesterol and triglyceride. Precalculated volumes of concentrates are added to human serum in order to prepare reference sera with desired levels of cholesterol or triglyceride, or both. The reference sera resemble human serum in appearance, composition, and stability. Properties of preparations are discussed and stability of reference sera is illustrated.

Blood Proteins↗
PubMed1981

Prostaglandin production and cellular aging.

Prostaglandin (PG) production by human embryo lung fibroblasts (HELF) is stimulated by a number of effectors including angiotensin, thrombin, bradykinin and ascorbic acid. The types of prostaglandins produced are to a degree effector-dependent. For example, angiotensin stimulates mainly PGE2 synthesis, thrombin stimulates production of both PGE2 and prostacyclin while bradykinin and ascorbic acid stimulate production of PGE2, PGF2 alpha, prostacyclin and thromboxane A2. Upon senescence in culture, prostacyclin (PGI2) production by HELF drops dramatically in response to ascorbic or arachidonic acids. An overall drop in prostaglandin synthesis is observed with bradykinin stimulation. Prostaglandin production is also related to senescence in human skin fibroblasts (HSF). These cells produce predominantly PGI2. Prostacyclin production in response to bradykinin drops in HSF as they are obtained from individuals of increasing chronologic age. Thus our results indicate changes in prostaglandin production upon senescence, a dependency of these changes on the given stimulus and a correlation between in vivo and in culture aging with respect to prostaglandin production.

6-Ketoprostaglandin F1 alpha↗
PubMed1981

Cell growth and the regulation of prostaglandin synthesis.

Prostaglandin (PG) synthesis was determined in human embryo lung fibroblasts (HELF) during active, slowed and non-growing phases. Bradykinin and ascorbic acid were used to induce PG synthesis. The cells were also exposed to arachidonic acid, a PG precursor. During active growth, PGE2 synthesis in response to stimulation by either bradykinin or ascorbic acid was low. As growth slowed the cellular response changed. During quiescence bradykinin and ascorbic acid stimulated PG production markedly while the conversion of free arachidonic acid to PGE2 also increased markedly. This change in response by quiescent cells was not due to an increase in cell density. When growing and quiescent cells at the same cell density were compared, the growing cells showed very little response to bradykinin while the quiescent cells were very responsive. The change in response was also not due to any difference in arachidonic acid concentrations in the culture medium during growth and non-growth.

Arachidonic Acids↗
PubMed1980

Chemical alkylation of lead (II) salts to tetraalkyllead (IV) in aqueous solution.

Methylation of lead in the environment would have serious consequences for water quality and for the well being of aquatic biota. As there is strong evidence that tetraalkylleads, the end products of lead alkylation, are considerably more toxic than lead (II) compounds, the elevated levels of inorganic lead now present in inland waterways and sediments as a result of industrial and motor vehicle emissions will pose a serious environmental hazard if mechanisms exist for the conversion to alkyllead (IV) species in aquatic systems. In the belief that the key to biological Pb(II) methylation lies in methyl transfer to Pb(II) from a carbonium ion donor (for example, S-adenosylmethionine), we recently initiated chemical and biological studies on the reactions of CH3+ donors with neutral and anionic Pb(II) compounds. We describe here the unequivocal synthesis of volatile tetramethyllead and other tetraalkylleads from Pb(II) salts and simple chemical reagents in aqueous solution. The known occurrence of methyl iodide in natural waters and our demonstration that Me4Pb is readily synthesized from this reagent and Pb(II) salts in aqueous solution could have far reaching significance not only for the chemical synthesis of toxic organoleads but also for possible mechanisms of microbiological methylation.

Alkylation↗
PubMed1980

Alterations in prostaglandin synthesis during senescence of human lung fibroblasts.

Prostaglandin (PG) synthesis by human embryo lung fibroblasts in culture was determined with increasing population doubling. These cultures synthesized PGE2, PGF2 alpha, PGI2 (prostacyclin) and TXA2 (thromboxane A2) in response to fetal bovine serum or ascorbic acid. Changes in prostaglandin synthesis by these cells during aging were observed in response to serum or ascorbic acid. These included a shift from the synthesis of PGI2 and PGE2 to TXA2 and PGF2 alpha and finally to PGF2 alpha alone. We also observed a marked increase during aging in the release of precursor fatty acid from lipid stores upon stimulation with ascorbic acid. A parallel decrease in the ability to convert the released fatty acid to prostaglandins was detected.

Cell Survival↗