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Biomedical subjects

C White

Publications and source records attributed to C White.

At least 199 records · Page 11Linked to original sources
PubMed1993

Microbial treatment of metal pollution--a working biotechnology?

Some of the main processes that remove, immobilize or detoxify heavy metals and radionuclides in the natural environment result from microbial activities. These activities can be harnessed to clean up toxic metal wastes before they enter the wider environment. To date, the most successful biotechnological processes utilize biosorption and bioprecipitation, but other processes such as binding by specific macromolecules may have future potential. Technologies using these processes are currently used to control pollution from diverse sources, including smelters and mine workings.

Adsorption↗
PubMed1993

Lack of importance of the superior laryngeal nerves in citric acid cough in humans.

The relative importance of laryngeal afferents in the cough reflex in humans is unknown. This study was designed to investigate the importance of superior laryngeal nerve afferents in the cough reflex induced by inhaled nebulized citric acid in awake humans. Nine healthy volunteers had their cough thresholds to inhaled nebulized citric acid measured after superior laryngeal nerve conduction blockade and after a sham nerve block. Of the nine subjects, four showed no change in cough threshold after superior laryngeal nerve anesthesia, three showed increased cough threshold after nerve block compared with no block, and two showed decreased cough threshold after nerve block. The geometric means of the cough thresholds for the nerve block vs. sham block tests were 16 +/- 13 (SD) and 15 +/- 8% citric acid, respectively. There was no statistically significant difference (Wilcoxon signed-rank test) between the cough thresholds with and without superior laryngeal nerve block (P > 0.05). We conclude that, in the awake human, superior laryngeal nerve afferents do not play a necessary role in initiation of citric acid-induced cough.

Administration, Inhalation↗
PubMed1993

A multicenter study on the use of pulsed low-intensity direct current for healing chronic stage II and stage III decubitus ulcers.

BACKGROUND AND DESIGN: Pulsed low-intensity direct current (300 to 600 microA) has been used in a double-blind placebo multicenter study in the treatment of stage II and stage III chronic decubitus ulcers. RESULTS: Seventy-four ulcers were treated in four centers. Forty-three patients were selected for the experimental group, and 31 control subjects used the sham instrument (placebo group). In the treated group, 25 ulcers (58%) healed in 8 weeks, whereas in the placebo group, only one ulcer (3%) healed and most ulcers increased in size. Statistical analysis, based on surface area and ulcer depth before and after treatment, showed that low-intensity direct current had a significant influence on the healing rates for these ulcers (P < .0001). Experiments with guinea pigs (n = 10) showed that pulsed low-intensity direct current caused a rapid calcium flux in the epidermis. CONCLUSIONS: Pulsed low-intensity direct current represents a useful approach for the treatment of stage II and stage III chronic decubitus ulcers by increasing the healing rate. The growth of fibroblasts and keratinocytes may be enhanced by pulsed low-intensity direct current due to changes in calcium homeostasis.

Adult↗
PubMed1993

Managing humor: when is it funny--and when is it not?

A survey of Canadian hospital nurses revealed they differentiate among situations in which humor would improve staff working relations. This intimates humor may be suitable for reducing nursing stress in some situations but not others.

Communication↗
PubMed1992

Structure of calcium 2,6-difluorobenzoate dihydrate.

Ca2+.2C7H3O2F2-.2H2O, M(r) = 390.3, monoclinic, C2/c, a = 17.584 (4), b = 10.771 (3), c = 7.887 (2) A, beta = 91.28 (2) degrees, V = 1493 A3, Z = 4, Dm = 1.75, Dx = 1.74 g cm-3, lambda(Mo K alpha) = 0.71073 A, mu = 4.92 cm-1, F(000) = 792, T = 293 K, final R = 0.037 for 2415 unique observed reflections. The eight-coordinate Ca2+ ion is linked to six carboxylate O atoms from four different 2,6-difluorobenzoate ions and two water molecules. Each 2,6-difluorobenzoate ion chelates one Ca2+ ion and forms unidentate bridging linkages to two other Ca2+ ions leading to a polymeric structure. Unlike the situation in calcium 2-fluorobenzoate, the two F atoms in this structure are not involved in significant C-F...H-O hydrogen bonding.

Benzoates↗
PubMed1992

Another pound of cure.

Explore the source record for details and available documents.

Health Services Accessibility↗
PubMed1992

Effects of a nursing education intervention on parents' knowledge of hydrocephalus and shunts.

The purpose of this nursing intervention study, which used a pre- and posttest design, was to determine the effect of an education program on parents' knowledge of hydrocephalus and shunt dynamics in a sample of parents of children with hydrocephalus. Study participants were parents of hydrocephalic children treated with an initial shunt or a shunt revision. The convenience sample of 41 subjects was divided into two groups (A or B). Group A participants were parents whose child received an initial shunt. Group B participants were parents whose child was admitted for a shunt revision. The shunt education intervention had three components: a shunt handbook, a preoperative teaching session with the clinical nurse specialist and a subsequent reinforcement teaching session. The pre- and posttest were the same seven multiple choice questions on hydrocephalus and shunts. In both groups, the pretest was given before the shunt education intervention. The posttest was given 2-3 weeks after the patient's surgery. There was a statistically significant change in the scores from the pre- and posttests for Group A (p = 0.0092). The nursing education appeared to have a positive effect upon this group's knowledge of hydrocephalus and shunts.

Adolescent↗
PubMed1992

Accumulation of Group 3 Late Embryogenesis Abundant Proteins in Zea mays Embryos : Roles of Abscisic Acid and the Viviparous-1 Gene Product.

Several different types of proteins that are modulated by abscisic acid (ABA) accumulate in developing embryos of maize (Zea mays L.). Some of these proteins are specific to the developing seed, such as the storage globulin, GLB1, whereas others are involved in general responses to water deficit. Here we describe a maize protein family of this second type, a Group 3 late embryogenesis abundant (MLG3). Like other proteins of this class, MLG3 polypeptides are ABA-responsive. They are found in maturing seeds and in dehydrating plant tissues. Antigenically related proteins are found in other cereals. To distinguish the regulation of developmentally programmed ABA responses from those that are environmentally induced, we compared the ontological pattern and accumulation requirements of MLG3 polypeptides with those we previously described for GLB1. GLB1 accumulation begins early in the maturation phase and specifically requires high levels of ABA and the participation of the Viviparous-1 (Vp1) gene product. Vp1 is required for other ABA-modulated events in maize seed development as well. In experiments using vp1 mutants and mutants deficient in ABA synthesis (vp5 mutation), we show that MLG3 accumulation also is dependent upon ABA, but it shows striking differences from GLB1. MLG3 accumulates much later in embryogenesis, coincident with the onset of dehydration. In contrast to GLB1, MLG3 proteins can be induced by de novo ABA synthesis in response to culturing in high osmoticum. Unlike GLB1, MLG3 has no specific requirement for the Vp1 gene product.

Journal Article↗
PubMed1992

Randomized trial of thrombolysis versus heparin in unstable angina.

BACKGROUND: The clinical usefulness of intravenous thrombolytic therapy in unstable angina is currently unknown, despite the pathogenetic similarity of this entity to acute myocardial infarction, for which thrombolysis has enjoyed great success. To compare the clinical benefit of intravenous urokinase with that of conventional antithrombotic therapy in preventing the progression of unstable angina to new myocardial infarction, intractable angina, or death within the first 96 hours after hospitalization, 149 patients with unstable angina were randomized to one of two intravenous thrombolytic strategies. METHODS AND RESULTS: Forty-nine patients received 3 million units urokinase i.v. over 90 minutes plus intravenous heparin (group A); 47 patients received unblinded 3 million units urokinase i.v. plus 325 mg aspirin p.o. daily (group B); and 53 patients received placebo thrombolytic infusion plus full-dose heparin (group C). The primary end point of this trial was 96-hour clinical status. There were no significant differences in the baseline characteristics (age, sex, previous myocardial infarction, hypertension prevalence, diabetes, tobacco use, or previous revascularization) among the three groups. Despite an excess of minor untoward reactions for the urokinase groups (chills, 26.5% and 23.4% for groups A and B versus 0% for group C; p < 0.01), there was no significant difference with respect to major bleeds (two, none, and two for groups A, B, and C, respectively; p = NS). At 96 hours after presentation, no significant difference emerged in the incidence of new cardiac events: new myocardial infarctions developed in 10.2% of group A, 6.4% of group B, and 3.8% of group C (p = NS); intractable angina occurred in 6.1% of group A, 10.6% of group B, and 9.4% of group C (p = NS). There were no deaths. All three groups encountered a similar incidence of overall cardiac events: 16.3%, 17.0%, and 13.2% for groups A, B, and C, respectively (p = NS). Although trial enrollment was to extend to 600 patients, interim analysis led to early cessation of enrollment due to a negative trend in respect to outcome after thrombolysis. CONCLUSIONS: High-dose intravenous urokinase followed by either heparin or aspirin can be safely administered to a broad, unselected group of patients with unstable angina. However, this study suggests that no clinical advantage is conferred by urokinase, with either adjunctive antithrombotic therapy over standard heparin therapy alone, when given relatively late (mean, 8.7 hours) after admission for unstable angina. A possible detrimental effect cannot be excluded.

Angina, Unstable↗
PubMed1992

No evidence for female-to-female HIV transmission among 960,000 female blood donors. The HIV Blood Donor Study Group.

The frequency of female-to-female HIV transmission was assessed among 960,000 female blood donors at 20 large U.S. blood centers during 1990. Of 144 HIV-seropositive women identified, 106 were interviewed. None of the interviewed women reported sex exclusively with women since 1978. Three seropositive women reported sex contact with women as well as with either bisexual men or men who had used i.v. drugs. In this large population, we identified no woman who was infected with HIV from sexual contact with another woman.

Adolescent↗