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Biomedical subjects

G Quintero

Publications and source records attributed to G Quintero.

29 records · Page 2Linked to original sources
PubMed1989

Displacement chromatography on cyclodextrin-silicas. II. Separation of cis-trans isomers in the reversed-phase mode on alpha-cyclodextrin-silica.

The feasibility of preparative separations of cis-trans isomers by displacement chromatography on analytical-scale alpha-cyclodextrin-silica columns operated in the reversed-phase mode is demonstrated by using the isomers of 3-hexen-1-ol as model substrates and n-alkanols as displacers. The importance of matching the size of the cyclodextrin cavity and the solutes is shown. The crucial role of the displacer (both type and concentration) in the success of the displacement chromatographic separation is demonstrated.

Chromatography, Liquid↗
PubMed1988

Liver transplantation: the first 200 grafts in Birmingham.

Improvements in perioperative management in this series have been balanced by an increase in the proportion of high-risk patients grafted, such that no overall improvement in survival has occurred. We suggest that for each patient 2 separate groups of risk factors are relevant: 1. Risk factors related to the transplant procedure itself: These include previous major upper abdominal surgery, marked cerebral edema due to fulminant hepatic failure, and severe portal hypertension including patients with recent major variceal bleeding. 2. Risk factors related to the recovery phase: These include patients in hepatorenal failure before grafting and those with severe muscle wasting. Greater experience and refinements in surgical technique have improved the outcome for patients with risk factors limited to the first group. However, those with risk factors in both groups remain a difficult problem and a significant proportion of the fatalities occur in patients who have come through the operation only to be lost from complications in the postoperative period. We feel this is one of the most important areas for future efforts if the results of liver replacement are to improve sufficiently to merit a wider application.

England↗
PubMed1982

A six-month clinical evaluation of decalcified freeze-dried bone allografts in periodontal osseous defects.

The osteogenic potential of decalcified freeze-dried bone allografts in the treatment of human periodontal osseous defects was evaluated over a 6 month period. Cortical bone, obtained under sterile conditions from a human donor within 24 hours after death, was decalcified, freeze-dried and ground to a particle size of 250 to 500 microns. Twenty-seven osseous defects with one-, two- and wide three-wall morphology were treated. Clinical measurements were made with a stent and a calibrated periodontal probe before surgery, at the time of surgery, and at re-entry. The combined mean osseous regeneration for all defects was 2.4 mm. This represented a 65% mean bone-fill of the original defect. The findings demonstrate that decalcified freeze-dried bone allograft has potential as an osseous grafting material in periodontal therapy.

Alveolar Process↗
PubMed1977

Screening for malnutrition with arm circumference.

The opinions on the performance characteristics of the mid arm circumference as anthropometric measurement for malnutrition screening are quite contradictory. In this paper we analyze the specificity and sensitivity of the arm tape under different conditions and conclude that the design of the tape characteristics should aim at an instrument which can satisfy specific needs instead of a general purpose one. We also give some measurements for the practical design of the instrument. 1. This investigation has been carried out under the Contract AID/ta-C-1121 and the Fundación para la Educación Superior. 2. Universidad del Valle. 3. Fundación para la Educación Superior. 4. Community Systems Foundation.

Anthropometry↗
PubMed1977

Comparative analysis of some anthropometric measurements.

The main objective of this work is to determine what anthropometric method to use under field conditions, given the kind of mainutrition to be detected. In the first part of the work some criteria and procedures are given by which to compare the field perfomance characteristics (i.e. transportability, facility of use, etc.), of the most commonly used instruments. Then we extrapolate these characteristics to the respective methods like weight for age, weight for height, height for age, etc. In the second part we present a correlation matrix among the various methods and analyze it in order to associate with each method a specific typology of malnutrition.

Age Factors↗
PubMed1976

The affinity of low density lipoproteins for an arterial macromolecular complex. A study in ischemic heart disease and controls.

Levels of serum cholesterol, triglycerides, lipoprotein pattern and the insolubilization of serum low density lipoproteins (LDL, betalipoprotein) by a factor present in arterial intima--media extracts was investigated in 55 patients with acute coronary heart disease and 50 healthy controls. In blood samples obtained 24 h after the episode, the serum betalipoproteins from male normotensive patients showed a high tendency to precipitate when incubated with the intima-media extracts, nearly twice the value measured in the control group. This affinity returned almost to control level after 21 days in the hospital. Hypertensive patients showed a serum cholesterol higher than the controls but almost no difference in LDL-arterial factor interaction. The composition of isolated LDL was studied in 7 patients and 8 controls and it was found that the total cholesterol/protein plus phospholipid ratio has a positive exponential correlation with the lipoprotein-arterial factor affinity. The results of LDL analyses suggest that a change in their composition, frequent in normotensive patients, can lead to an increased affinity of this lipoprotein for arterial intimamedia components. It is proposed that this process could be an additional risk factor contributing to the deposition of LDL in the arterial wall.

Adult↗
PubMedDate not supplied

The semantics of addiction: moving beyond expert models to lay understandings.

Five expert discourses on addiction purport to explain the phenomenon of the semantics of addiction. An assessment of the burgeoning use of this term by the lay public, however, reveals a plethora of socially contextualized and culturally mediated meanings related to addiction that are generally not considered by expert models. Addiction has meanings that index the loss of self-control and individual responsibility, as well political and moral meanings and meanings that index social modes of consumption, the range and limits of normative behavior, and the constitution of deviance. The category of addition interacts with other socially produced categories, including "drugs" and "desires," and implies an unfolding history linked to specific cultural conventions of what is proper. This paper briefly reviews expert debates over the meanings of addiction and explores the semantics of how this term is used in both popular discourse and among those who use substances associated with physical addiction. In addition, some of the more interesting theoretical issues this discussion brings to light are highlighted, with the intent to identify issues warranting future research that will broaden the study of addiction.

Humans↗