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Biomedical subjects

M Garrett

Publications and source records attributed to M Garrett.

12 recordsLinked to original sources
PubMed1992

Disorders of lexical selection.

Errors in lexical processing are commonplace in language pathologies resulting from brain injury or disease. This discussion considers some of the major recent developments in the interpretation of such errors. The focus is on behavioral systems, rather than neuroanatomical or neurophysiological issues. The objective is to comment on some plausible mutual implications of generally attested pathologies and normal models of lexical retrieval for production, particularly with respect to the roles of semantic and syntactic categories.

Female↗
PubMed1992

Hydrolysis of GTP by Sec4 protein plays an important role in vesicular transport and is stimulated by a GTPase-activating protein in Saccharomyces cerevisiae.

Sec4, a GTP-binding protein of the ras superfamily, is required for exocytosis in the budding yeast Saccharomyces cerevisiae. To test the role of GTP hydrolysis in Sec4 function, we constructed a mutation, Q-79----L, analogous to the oncogenic mutation of Q-61----L in Ras, in a region of Sec4 predicted to interact with the phosphoryl group of GTP. The sec4-leu79 mutation lowers the intrinsic hydrolysis rate to unmeasurable levels. A component of a yeast lysate specifically stimulates the hydrolysis of GTP by Sec4, while the rate of hydrolysis of GTP by Sec4-Leu79 can be stimulated by this GAP activity to only 30% of the stimulated hydrolysis rate of the wild-type protein. The decreased rate of hydrolysis results in the accumulation of the Sec4-Leu79 protein in its GTP-bound form in an overproducing yeast strain. The sec4-leu79 allele can function as the sole copy of sec4 in yeast cells. However, it causes recessive, cold-sensitive growth, a slowing of invertase secretion, and accumulation of secretory vesicles and displays synthetic lethality with a subset of other secretory mutants, indicative of a partial loss of Sec4 function. While the level of Ras function reflects the absolute level of GTP-bound protein, our results suggest that the ability of Sec4 to cycle between its GTP and GDP bound forms is important for its function in vesicular transport, supporting a mechanism for Sec4 function which is distinct from that of the Ras protein.

Amino Acid Sequence↗
PubMed1992

Development and use of preprinted forms and adhesive labels in medical record charting.

Clear delineation of specific clinical and administrative responsibilities (eg, content requirements, cost constraints) is necessary in the development, approval, and implementation of effective preprinted documentation materials. Input early in the development stage from medical record and legal department staff ensures that proposed materials will meet organizational and legal standards. The development and use of time-saving preprinted documentation materials in medical record charting by the Johns Hopkins Oncology Nutrition Service is described. We conclude that the use of preprinted materials expedites and enhances both the consistency and quality of documentation.

Dietary Services↗
PubMed1991

Adult and fetal human mesangial cells interact with specific laminin domains.

Mesangial cells are centrally located pericytes in the renal glomerulus. They are surrounded by an extracellular matrix and directly contact the glomerular basement membrane in vivo. Because these interactions are critical for renal development and function, we have studied human mesangial cell interactions with laminin, a major adhesive component of basement membranes present in the extracellular matrix of the mesangium. Human fetal and adult mesangial cell attachment was stimulated by both laminin and the laminin-derived synthetic peptides YIGSR-NH2, CQAGTFALRGDNPQG-NH2, and CIKVAVS-NH2. Furthermore, mesangial cells spread on laminin as well as on both the RGD-containing and CIKVAVS peptides. When added in solution, all three peptides inhibited mesangial cell attachment to laminin, and the latter two peptides inhibited mesangial cell spreading on laminin. Laminin affinity column chromatography demonstrated several low-molecular-mass laminin-binding proteins ranging from between 35 and 42 kDa, which predominated in fetal mesangial cells, whereas a higher molecular mass laminin-binding protein of 65 kDa was predominant in adult mesangial cells. Western blot analysis with an anti-32-kDa laminin-binding protein antibody showed increased expression of both 31- and 42-kDa proteins in fetal mesangial cells when compared with the adult. The antisera to the 32-kDa laminin-binding protein also inhibited fetal mesangial spreading on the CIKVAVS peptide. Western blot analysis with an anti-67-kDa laminin-binding protein antibody revealed a 110-kDa protein in adult mesangial cells that was not present in fetal mesangial cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Down-regulation of mannose receptor activity in macrophages after treatment with lipopolysaccharide and phorbol esters.

We have investigated the effects of LPS and PMA on the expression of functional mannose receptors in rat bone marrow-derived macrophages. After 48 h of treatment with LPS (10 ng/ml) and PMA (100 nM), mannose receptor activity was reduced by 70 to 80%. The effect of these agents on receptor activity was not reversible, and activity continued to decline after the agents were removed. Pretreatment of cells with dexamethasone was effective in blocking the LPS/PMA-induced down-regulation. Serine protease inhibitors did not block the reduction in receptor activity, suggesting that proteolysis is not involved in receptor down-regulation. LPS/PMA treatment did not increase turnover of the receptor. Ligand uptake studies showed that the total capacity of the uptake system was reduced by 80%, although the Kuptake was unaffected. Binding of 125I-mannose-BSA to intact macrophages showed a 70% decrease in surface receptor activity after treatment with LPS/PMA. LPS/PMA treatment had no effect on total receptor synthesis as quantitated by immunoprecipitation of metabolically labeled receptor. However, binding of metabolically labeled receptor to mannose-Sepharose, and binding of 125I-mannose-BSA to immunoprecipitated receptor revealed that intracellular plus surface binding sites were reduced to approximately 30% after LPS/PMA treatment. These results suggest that LPS/PMA treatment of macrophages results in an inactivation of mannose receptors with no effect on receptor turnover or biosynthesis.

Animals↗
PubMed1987

Effect of chloroquine on intestinal lipid metabolism.

Most studies that have quantitated recovery of infused lipid in the intestinal mucosa and mesenteric lymph have only been able to recapture 50-75%. One possibility is that the missing lipid enters a triacylglycerol (TG) storage pool in the enterocyte and is hydrolyzed by lysosomal lipase, and the free fatty acid released is transported by the portal vein. This postulate was tested by comparing glyceryl trioleate (TO)-infused rats pretreated with the lysosomotropic drug, chloroquine (6.3 mg.kg-1.h-1) with saline controls. Chloroquine increased mucosal TG from 94 +/- 6 to 128 +/- 8 mumol. Additionally, the specific activity of the mucosal TG relative to the infused [3H]TO was reduced in the treated rats. The mucosal TG increase was not due to impaired TG output, which remained the same as controls. We conclude that the TG in the acid lipase-sensitive pool derives most of its glyceride-glycerol from endogenous sources. Furthermore, the increment in mucosal TG caused by chloroquine is not enough to explain the majority of the acyl groups unaccounted for in the mucosa and lymph after a TG infusion. For these a direct passage of acyl groups through the enterocyte is postulated.

Animals↗
PubMed1985

Grammatical class effects in relation to normal and aphasic sentence processing.

Agrammatic, Broca's aphasic patients, Wernicke's aphasic patients, and neurologically intact control subjects were asked to detect target letters in prose passages and in a scrambled word passage. The targets were embedded, in some instances, in content words (open-class vocabulary items), and in other instances, in function words (closed-class vocabulary items). With respect to the prose passages, both the control subjects and Wernicke's aphasic patients were more apt to notice target letters when they appeared in the open-class items than when in closed-class items; by contrast, the agrammatic Broca's patients showed no vocabulary class detection difference. The Wernicke's patients were not entirely normal, however: Whereas the normal subjects showed a much smaller vocabulary class effect for letter detection in the scrambled condition, the Wernicke's maintained the pattern they had shown in the prose condition. These and other findings obtained on the letter cancellation task are discussed in relation to lexical access mechanisms geared to sentence parsing.

Adult↗
PubMed1971

"Tobispray.

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Aerosols↗