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Biomedical subjects

J L White

Publications and source records attributed to J L White.

At least 55 records · Page 3Linked to original sources
PubMed1993

The effect of aluminum hydroxide dissolution on the bleeding of aluminum lake dyes.

The effect of pH on the bleeding of FD&C yellow No. 5 aluminum lake and FD&C red No. 40 aluminum lake was investigated. The pH-bleeding profiles corresponded to the pH-solubility profile of aluminum hydroxide. The similarity of the bleeding profiles of both lake dyes and the pH-solubility profile of aluminum hydroxide indicates that pH related bleeding, other than that occurring by competition with anions, is a result of dissolution of the aluminum hydroxide substrate. This dissolution is related to the properties of the substrate rather than to the structure of adsorbed dye.

Aluminum Hydroxide↗
PubMed1993

Does the choice of local anesthetic affect the catecholamine response to stress during epidural anesthesia?

BACKGROUND: Previous work has established that 2-chloroprocaine epidural anesthesia has no effect on circulating plasma epinephrine concentrations in young, healthy, resting volunteers, and results in a decrease in norepinephrine concentration only when a level of analgesia to pinprick of C-8 is reached. The current study was performed to evaluate the possibility that this finding is unique to 2-chloroprocaine. METHODS: Nine healthy volunteers were studied on three occasions at least 48 h apart; each received three local anesthetics (0.75% bupivacaine, 2% lidocaine, and 3% 2-chloroprocaine, all without epinephrine). After placement of lumbar epidural and central venous catheters, blood samples were drawn from the central venous catheter at the following stages: (1) 20 min after catheter placement (baseline), (2) during the first cold pressor test (CPT; hand held in an ice water bath for 90 s), (3) 20 min after reaching epidural analgesia to T-1 level of analgesia, and (4) during a second CPT (epidural analgesia to T-1). Monitoring consisted of noninvasive cardiac output (impedance), noninvasive blood pressure, and EKG. RESULTS: Extensive epidural block (stage 3) altered measured variables only minimally with respect to resting baseline state. During stage 2 (first CPT), mean arterial pressure (MAP), heart rate (HR), cardiac index (CI), epinephrine, and norepinephrine increased. During stage 4 (second CPT), increases in HR and CI were not attenuated by any of the three local anesthetics. Increases in MAP were attenuated by epidural anesthesia with all three local anesthetics. Bupivacaine and 2-chloroprocaine epidural anesthesia significantly attenuated increases in plasma catecholamines, but lidocaine epidural anesthesia did not. CONCLUSIONS: Epidural anesthesia with all three local anesthetic agents tested resulted in an incomplete sympathectomy in the resting state in healthy young men, judged by plasma catecholamine concentrations and cardiovascular variables minimally changed from resting baseline. Lidocaine epidural anesthesia did not attenuate the catecholamine response to CPT, indicating decreased blockade of sympathetic efferent neural traffic compared with bupivacaine and chloroprocaine epidural anesthesia.

Adult↗
PubMed1992

Direct angioplasty versus initial thrombolytic therapy for acute myocardial infarction: long-term follow-up and changes in practice pattern.

We retrospectively studied the outcomes of patients with acute myocardial infarction who were treated with either direct angioplasty or thrombolytics followed by angioplasty. Two patient cohorts were analyzed: a previously reported (in regard to short-term follow-up) group of 371 patients who now have long-term follow-up (mean, 3.4 years) of survival and event-free survival and a second group of 202 patients who have been treated since publication of our initial data. Both 1-year and 2-year survival were significantly better (p = 0.01 and 0.02, respectively) in the group that was treated with thrombolytics first. Event-free survival (i.e., no myocardial infarction, coronary artery bypass graft surgery, repeat angioplasty) was better overall (p < 0.01) for the group that was treated with thrombolytics first. The more recently treated group of patients also showed benefit in regard to both survival (p = 0.002) and event-free survival (p < 0.01) over a short-term follow-up period (mean, 39 weeks) for patients who were treated initially with thrombolytics as compared with those who were treated with direct angioplasty. Although the initial cohort was very similar to the treatment groups except for age (mean age for the direct angioplasty group was 62 +/- 12 years vs 57 +/- 11 years for thrombolytics first group, (p = 0.0002), several differences existed in the more recent treatment groups. The patients who were more recently treated with direct angioplasty were older, had lower mean ejection fraction, had more extensive coronary artery disease, and were more likely to have had prior coronary artery bypass grafting.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Contribution of soluble aluminium species to absorption of aluminium from the rat gut in situ.

1. Rat gut perfusion studies in vivo at pH 4, 6 or 8 using aluminium chloride or equimolar aluminium chloride and sodium citrate showed that elevated plasma aluminium concentrations were associated with aluminium solubility in the perfusion. Elevated plasma aluminium levels and soluble aluminium in the perfusate occurred with perfusion of equimolar aluminium chloride and sodium citrate at all three pH values. 2. Partitioning studies in vitro, utilizing water and ethyl acetate, revealed that uncomplexed aluminium exhibited maximum partitioning into the ethyl acetate phase at pH 2.5. When complexed with citrate, aluminium exhibited partitioning over a much broader pH range, pH 2.5-8.0. 3. A direct linear relationship was observed between the soluble aluminium concentration of the perfusate and the increase in the plasma aluminium level, suggesting that soluble aluminium is absorbed by a passive diffusion mechanism.

Aluminum↗
PubMed1992

The federal refocusing on long-term care.

Widespread public support for a federally funded long-term care program coupled with election-year politics have prompted the introduction of numerous legislative proposals to help the millions of Americans who suffer from disability and chronic illness of long-term duration.

Aged↗
PubMed1992

Neuropsychological and socio-emotional correlates of specific-arithmetic disability.

Neuropsychological and socio-emotional factors associated with specific-arithmetic disability were investigated in an unselected sample of New Zealand children. Subjects were 17 specific-arithmetic disabled, 27 specific-reading disabled, 63 generally disabled, and 50 nondisabled 13 year olds. Evidence was sought for an association between specific-arithmetic disability and the neuropsychological and socio-emotional correlates of Nonverbal Learning Disability syndrome (NLD). NLD is characterized by a pattern of nonverbal and verbal neuropsychological strengths and weaknesses, and appears to place individuals at greater risk for internalizing psychopathology, than other learning disabilities. Only specific-arithmetic disabled subjects were found to show a neuropsychological profile reminiscent of NLD. Evidence of poor socio-emotional adjustment was found across all three learning-disabled groups, and was greatest among generally disabled subjects. We found that the specific-arithmetic-disabled subjects exhibited the greatest degree of overlap between internalizing psychopathology and a NLD neuropsychological profile. The results are interpreted as providing some support for the idea that specific-arithmetic-disabled individuals may be at greater risk for the NLD syndrome than either generally disabled or specific-reading-disabled individuals.

Journal Article↗
PubMed1991

The location of exon boundaries in the multimeric iron-storage protein ferritin.

The nature of the amino acids whose codons border introns in ferritin genes is novel; the disposition of these intron boundaries within the three-dimensional structure of the 24-subunit molecule differs significantly from that of other proteins. These observations are discussed in relation to the functions of isoferritins.

Amino Acid Sequence↗
PubMed1991

Predicting the adsorption of proteins by aluminium-containing adjuvants.

The adsorption of two model proteins, albumin and lysozyme, by boehmite or amorphous aluminium hydroxyphosphate adjuvants was studied. Electrostatic, attraction has a major role in adsorption. At physiological pH, boehmite, which has a point of zero charge above 7.35, extensively adsorbed albumin, which has an isoelectric point of 4.8, but was not effective in adsorbing lysozyme (isoelectric point, 11.0). Conversely, amorphous aluminium hydroxyphosphate (point of zero charge, 4.0) was effective in adsorbing lysozyme but adsorbed relatively little albumin. The results suggest that the selection of either boehmite or amorphous aluminium hydroxyphosphate as an adjuvant should be based in part on the isoelectric point of the antigen.

Adjuvants, Immunologic↗
PubMed1991

Effect of competing anions on binding of bile salts by cholestyramine.

The binding of bile salts by cholestyramine may be influenced by other anions, as the Langmuir adsorption coefficients for three bile salts tested were similar to the model anion, citrate. However, the selectivity coefficient indicated preferential binding of cholate anion in comparison to citrate anion. Binding experiments confirmed cholestyramine's preference for bile salts as the presence of other anions reduced but did not prevent the binding of cholate anion. Binding of cholate anion was reduced in direct relationship to the citrate anion concentration. Prior exposure of cholestyramine to citrate anion caused the binding of cholate anion to decrease slightly. Sequential exposure of cholestyramine to simulated gastric fluid and simulated intestinal fluid containing cholate anion resulted in a decrease in cholate binding which was attributed to competition with anions present in the gastrointestinal fluids. Components of tomato juice and orange juice, fluids, commonly used to enhance ingestion of cholestyramine, also reduced the binding of cholate anion.

Adsorption↗
PubMed1990

Aluminum compounds used as adjuvants in vaccines.

The structure of nine commercially manufactured aluminum-containing adjuvants was investigated by X-ray diffraction, infrared spectroscopy, transmission electron micrography, and energy dispersive spectrometry. Seven samples which were labeled as aluminum hydroxide were identified as boehmite, a crystalline aluminum oxyhydroxide [AlO(OH)]. However, the degree of crystallinity varied between the samples. Two samples which were labeled as aluminum phosphate were found to be amorphous aluminum hydroxyphosphate. Buffer anions and sulfate anions substitute for hydroxyls in the amorphous aluminum hydroxide formed by the in situ alum precipitation method. Finally, the aluminum-containing adjuvant in diphtheria and tetanus toxoid, U.S.P., produced by three manufacturers was characterized.

Adjuvants, Pharmaceutic↗
PubMed1989

A simple method for detection of viral satellite RNAs in small plant tissue samples.

A procedure is described that allows extraction and can estimate the total amount of single-stranded and double-stranded viral satellite RNAs and viral RNA present in a minimal amount of infected plant tissue, and is capable of distinguishing different cucumber mosaic viral and nepoviral satellites by polyacrylamide gel electrophoresis under semi-denaturing or fully-denaturing conditions.

Blotting, Northern↗
PubMed1989

In vitro adsorption of bile salts by colestipol hydrochloride.

The acid-base titration of colestipol hydrochloride exhibits no sharp inflection points, indicating a weakly basic anion-exchange copolymer. The swelling of colestipol hydrochloride in water and the adsorption of cholate anion are inversely related to pH and are, therefore, related to the ionization state of the copolymer. The Langmuir adsorption parameters at pH 7.5 and 37 degrees C are similar for cholate, glycocholate, and taurocholate anions. Adsorption capacity was not related to particle size and exceeded the adsorptive capacity of the external surface by three orders of magnitude. Therefore, it is believed that the swelling of colestipol hydrochloride makes extensive internal surface area available for adsorption of bile salts. The rate of adsorption depends on the concentration of sodium cholate to which the colestipol hydrochloride is exposed. Adsorption was complete within 5 min when the concentration was below the adsorptive capacity. In contrast, adsorption at levels of sodium cholate at or above the adsorptive capacity was not complete within a 3-hr test period.

Adsorption↗
PubMed1989

Effect of anions on adsorption of bile salts by colestipol hydrochloride.

The Langmuir affinity constant and adsorptive capacity for the adsorption of citrate anion or cholate anion by colestipol hydrochloride at pH 7.5, 37 degrees C, were similar. Prior exposure of colestipol hydrochloride to citrate anion caused the adsorption of cholate anion to decrease slightly in comparison to a control utilizing only cholate anion. The concentration of citrate anion was found to be directly related to the decrease in cholate anion adsorption. Simultaneous exposure of colestipol hydrochloride to citrate and cholate anions at pH 7.5, 37 degrees C, resulted in the same adsorption of cholate anion as sequential exposure to citrate anion followed by cholate anion. Sequential exposure of colestipol hydrochloride to simulated gastric fluid and simulated intestinal fluid containing cholate anion resulted in a small decrease in cholate adsorption which was attributed to competition with phosphate anion in simulated intestinal fluid. Pepsin in the simulated gastric fluid did not affect adsorption of cholate anion from simulated intestinal fluid. Preexposure to components of tomato juice and orange juice also slightly reduced the adsorption of cholate anion by colestipol hydrochloride.

Adsorption↗
PubMed1989

A prospective replication of the protective effects of IQ in subjects at high risk for juvenile delinquency.

The purpose of the study was to test the replicability of a protective effect of high IQ against criminality. Support has been found in prior studies for the hypotheses that Ss at high risk would have an elevated risk of serious criminal involvement, that seriously criminal Ss would have a lower mean IQ score than noncriminal Ss, and that Ss at high risk who had not become involved in serious criminal behavior would have the highest IQs. This report tests these hypotheses in a prospective design. Subjects were 1,037 members of a longitudinal investigation of a New Zealand birth cohort. IQs were examined for male and female Ss who were divided into 4 groups formed on the basis of risk status at age 5 years and delinquency outcome at ages 13 and 15. Analyses were conducted with and without mild delinquents excluded from the nondelinquent groups. We found that male and female delinquents showed significantly lower IQ scores than nondelinquents. By varying S selection procedures, we also found that a very high IQ may help boys, even those at risk, to stay free of delinquency altogether.

Child, Preschool↗