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S Flores

Publications and source records attributed to S Flores.

33 records · Page 2Linked to original sources
PubMed1991

Expression and regulation of UDP-glucuronate: neolactotetraosylceramide glucuronyltransferase in the nervous system.

Sulfoglucuronyl glycolipids (SGGLs) are temporally and spatially regulated molecules present in the nervous system during its development. The characteristics of the rat brain enzyme glucuronyltransferase involved in the biosynthesis of SGGLs have been described. The enzyme catalyzes the transfer of glucuronic acid (GlcA) from UDP-GlcA to terminal galactose of the neolacto (type 2) series of glycolipids to form beta 1-3-linked glucuronyl neolacto glycolipids. The enzyme was highly specific for the neolacto series of acceptor glycolipids, neolactotetraosylceramide (nLcOse4Cer), neolactohexaosylceramide (nLcOse6-Cer), and neolactooctaosylceramide (nLcOse8Cer) and was different from the drug-inducible phenol:GlcA transferase. Considerable activity of GlcA transferase was present in the adult rat cerebral cortex, even though SGGLs almost completely disappeared from the cortex by postnatal day 15. In the cerebellum, although levels of SGGLs increased with development, the specific activity of GlcA transferase declined. The results indicated that GlcA transferase was not a regulatory enzyme controlling the expression of SGGLs. Measurements of the levels of nLcOse4Cer and nLcOse6Cer in these neural tissues indicated that the availability of these precursors may regulate the differential expression of SGGLs seen previously. GlcA transferase was significantly reduced in the cerebellar Purkinje cell degenerating murine mutant (pcd/pcd), which is consistent with the loss of SGGLs in the cerebellum of this mutant and specific association of these glycolipids with Purkinje cells.

Animals↗
PubMed1991

High-level expression of a tobacco chitinase gene in Nicotiana sylvestris. Susceptibility of transgenic plants to Cercospora nicotianae infection.

Endochitinases (E.C.3.2.14, chitinase) are believed to be important in the biochemical defense of plants against chitin-containing fungal pathogens. We introduced a gene for class I (basic) tobacco chitinase regulated by Cauliflower Mosaic Virus 35S-RNA expression signals into Nicotiana sylvestris. The gene was expressed to give mature, enzymatically active chitinase targeted to the intracellular compartment of leaves. Most transformants accumulated extremely high levels of chitinase-up to 120-fold that of non-transformed plants in comparable tissues. Unexpectedly, some transformants exhibited chitinase levels lower than in non-transformed plants suggesting that the transgene inhibited expression of the homologous host gene. Progeny tests indicate this effect is not permanent. High levels of chitinase in transformants did not substantially increase resistance to the chitin-containing fungus Cercospora nicotiana, which causes Frog Eye disease. Therefore class I chitinase does not appear to be the limiting factor in the defense reaction to this pathogen.

Base Sequence↗
PubMed1990

Loss of sulfoglucuronyl and other neolactoglycolipids in Purkinje cell abnormality murine mutants.

A significant reduction in the content of two members of the sulfoglucuronyl-neolacto series of glycolipids (SGGLs), 3-sulfoglucuronyl-lacto-N-neotetraosylceramide (SGGL-1) and 3-sulfoglucuronyl lacto-N-norhexaosylceramide (SGGL-2), in the cerebellum of the Purkinje cell abnormality mutants, Purkinje cell degeneration (pcd/pcd), lurcher (Lc/+), and staggerer (sg/sg), was also confirmed in the mildly affected nervous (nr/nr) mutant. The expression of SGGLs was studied during development of the pcd/pcd mutant cerebellum, and it was shown that the rate of decline in the level of SGGLs practically coincided with the loss of Purkinje cell perikarya. This indicated that SGGLs are primarily localized in Purkinje cells and that initially, at least, there is no genetic defect in the biosynthesis of SGGLs in the mutant. The precursors of SGGLs, viz., lacto-N-neotetraosylceramide (paragloboside) and lacto-N-norhexaosylceramide, as well as other glycolipids derived from these precursors, such as X-determinant fucoglycolipids and disialosyllacto-N-neotetraosylceramide, were also present in normal cerebellum. Levels of paragloboside and its other derivatives, similar to SGGLs, were also significantly reduced in the Purkinje cell abnormality mutants pcd/pcd, sg/sg, Lc/+, and nr/nr but were normal in other cerebellar mutants, such as quaking (qk/qk), weaver (wv/wv), and reeler (rl/rl), where Purkinje cells are not involved. Thus, the entire paragloboside family of glycolipids is primarily associated with Purkinje cells in the cerebellum. Although levels of monoclonal antibody HNK-1-reactive glycolipids were reduced in the Purkinje cell abnormality mutants, HNK-1-reactive glycoproteins were not affected in these mutants.

Animals↗
PubMed1990

Identification of disialosyl paragloboside and O-acetyldisialosyl paragloboside in cerebellum and embryonic cerebrum.

The lacto series of glycolipids are only minor constituents in mammalian CNS and are found mostly during development. Expression of a significant amount (70 micrograms of neuraminic acid/g dry weight) of disialosyl-lacto-N-neotetraosylceramide (LD1) in adult mouse cerebellum is reported for the first time in the nervous system. The structure of this ganglioside was determined by hydrolysis with various glycosidases, immunochemical tests, sugar and fatty acid analyses after permethylation and capillary GLC-mass spectrometry, sugar linkage analysis of permethylated alditol acetates, and fast-atom bombardment-mass spectrometry of the native ganglioside. The structure of LD1 was determined to be NeuAc-NeuAc alpha 2-3Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4Glc beta 1-1-ceramide. The major fatty acid was 18:0, and the long-chain base was C18-sphingenine. Mouse cerebellum also contained O-acetyl-LD1 and several other O-acetylated gangliosides as recognized by monoclonal antibodies ME311 and 3G5. The levels of LD1 and O-acetyl-LD1 in cerebellum increased during postnatal development. During development of the Purkinje cell degeneration mutant, pcd/pcd, the levels of both of these gangliosides in the cerebellum declined with the loss of Purkinje cells, a finding indicating that these gangliosides are primarily associated with Purkinje cells. In the cortex, LD1, O-acetyl-LD1, and O-acetyl GD3, like GD3, are developmentally regulated antigens and are only expressed in the fetal cortex and not to any significant extent in the adult.

Animals↗
PubMed1983

Recruitment of institutional psychiatrists for the 50 states.

We studied institutional recruitment of non-federal psychiatrists in 1979 as measured by national advertisements. Vacant positions in state mental hospitals and CMHCs are over-represented in the adverts compared to the current institutional distribution of physicians practicing psychiatry. States' per capita recruitment rates vary widely, but do not decrease linearly or exponentially with increasing abundance of psychiatrists. The percentage increase sought in institutional psychiatrists ('recruitment intensity'), however, does decrease exponentially as institutional psychiatrists/100,000 population increase. Recruitment rates and recruitment intensity are not highly correlated with states' sociodemographic characteristics or with characteristics of their health care systems. Private sector recruitment, however, is significantly higher in states that have mandated psychiatric benefit packages in private insurance. Studies relating institutional recruitment or vacancy rates to measures of local demand for psychiatric services are needed, as well as comparisons of successful versus unsuccessful institutions. Institutional vacancies are undoubtedly affecting the quality of care, compliance with standards for reimbursement and ability to generate third-party revenues. Greater understanding of institutional recruitment is needed.

Community Mental Health Centers↗
PubMedDate not supplied

Validation of the verbal autopsy method to ascertain acute respiratory infection as cause of death.

The validity of the Verbal Autopsy (VA) in death due to acute respiratory infection (ARI), was tested in 36 children who died by any acute infectious disease as stated by the necropsy diagnosis, at two public hospitals in Mexico City; the illness started at home. Clinical data obtained through VA were compared with diagnoses of necropsies, which were considered as "gold standard". The presence of dyspnoea for more than one day showed sensitivity of 0.69 and specificity of 0.74, while history of coughing showed a sensitivity of 0.61 and a specificity of 0.73. Combination of both clinical data improved specificity (0.83), but decreased sensitivity (0.54). Additional sources of diagnosis (a panel of assessors, the clinical record and the death certificate), also showed good sensitivity (0.69-0.77) and specificity (0.74-7.8). Focus on history of dyspnea and/or cough in children with an infectious syndrome should be emphasized, as a useful epidemiologic tool to determine children's mortality due to ARI in areas where diagnosis resources are constrained.

Autopsy↗
PubMedDate not supplied

[Training in dietetics and nutrition from the point of view of the primary care physician].

BACKGROUND AND GOALS: Professionals in primary health care have to face a large number of patients with pathologies arising out of nutritional and dietary disorders as well as cope with society's growing interest in such issues. For this reason, we have attempted to assess the extent of the knowledge in questions of nutrition and dietetics that primary health care doctors feel they have received in comparison with what they might have considered necessary, as well as assess the capacity that these doctors feel they have to cope with clinical situations requiring a knowledge of nutrition. SCOPE AND SUBJECTS: 250 doctors working in Primary Health Care and belonging to the Tarragona Province Medical Association. ACTION: Participants received a self-administered questionnaire in which they had to: a) answer closed questions on their sense of clinical ability to handle dietary and nutritional problems; b) give a score for the importance that 62 previously-defined subjects should have in their general medical training; and c) give a score for the attention paid to these topics during their undergraduate training. RESULTS: 36 doctors (age: 38.6 +/- 10 years) with an average accumulated experience in medicine of 12.5 +/- 9.2 years replied to the survey. Respondents reported that 42.5 +/- 25% of their patients required nutritional or dietary action and only 28 +/- 24% receive the same. As for their undergraduate training in nutrition, 19.4% of them considered it to be non-existent and 58.4% described it as insufficient. Respondents reported little ability to handle different clinical situations, particularly involving the identification of patients requiring secondary vitamin therapy or nutritional support and the prescription of low lactose diets. Except for the area of biochemistry and nutritional physiology, respondents reported a great discrepancy between the attention that should have been given during their undergraduate years to the subjects proposed and the training they really received, particularly in questions of clinical dietetics, diet and the prevention of disease as well as nutritional support in disease. CONCLUSIONS: The undergraduate training in questions of dietetics and nutrition is clearly seen to be scant according to primary health care physicians. This might explain in part the insufficient clinical capacity that these professionals feel they have in such matters and the high percentage of patients who do not receive the nutritional and dietary attention these doctors feel is necessary.

Clinical Competence↗
PubMedDate not supplied

Repairability of polyacid-modified composite resin.

The purpose of this study was to evaluate the effect of time and surface treatment on the resulting shear bond strength of a repaired polyacid-modified composite resin restorative material (VariGlass VLC). Seventy-two specimens of VariGlass were prepared in cavities (2 mm X 7 mm) cut into acrylic resin cylinders. The specimens were then divided into three groups of 24. For each of the three groups, 12 of the specimens were repaired 5 minutes after the cavities were initially filled, while 12 specimens were repaired 1 week after the initial fill. The VariGlass surfaces were treated in one of the following ways: no treatment; primer (30 seconds) and adhesive (light activated for 10 seconds); or 37% phosphoric acid etchant (30 seconds), primer (30 seconds), and adhesive (light activated for 10 seconds). Repairs were made using a split polytetrafluoroethylene mold (3 mm X 5 mm) mounted over the exposed VariGlass surface. After bonding a cylinder of VariGlass to the treated surfaces, the specimens were thermocycled 500 times (5 degrees C and 55 degrees C water baths), stored in distilled water for 1 week, and loaded to failure in shear at 0.5 mm/min. Data were analyzed using two-way ANOVA and a Student-Newman-Keuls multiple comparison test. Results indicated that the bond strength of specimens repaired at 5 minutes was significantly higher when no surface treatment was used prior to repair. Bond strength of specimens repaired at 1 week was unaffected by surface treatment. Time of repair significantly affected the no-treatment and the primer-adhesive groups.

Acrylic Resins↗