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Biomedical subjects

B Campbell

Publications and source records attributed to B Campbell.

At least 73 records · Page 4Linked to original sources
PubMed1998

Which treatment would patients prefer for their varicose veins?

This questionnaire-based study investigated the preferences of patients with varicose veins for injection treatment or surgery, based on a series of explicit facts about each method. In all, 72 questionnaires were returned (77% response rate). Factors influencing patients in favour of injections were no time off work (38%) and no general anaesthetic (31%). A bandage on the leg for 3-6 weeks influenced 44% against injections. A lower chance of recurrence at 5-10 years influenced 80% of patients towards surgery. Overall, 25% expressed an overall preference for injections, and 63% preferred surgery (12% no preference). Patients with bilateral varicose veins were asked about their preferences for two unilateral day case operations or one bilateral inpatient procedure. The majority preferred a single bilateral operation, based on one general anaesthetic (88%) and one admission only (77%), less time off work (58%), and discomfort on one occasion only (50%). These preferences, expressed by well-informed patients, should be considered when planning services for the treatment of varicose veins.

Adult↗
PubMed1998

Validation of the laboratory information system.

OBJECTIVE: To present an organized and practical approach to the validation of laboratory information systems. SOURCES: Personal experience, published papers, technical manuals, and Food and Drug Administration guidelines. DATA: Validation of the laboratory information system is the continuing process of proving the system fit for its intended use, initially and over time. It consists in defining, collecting, maintaining, and independently reviewing evidence that the system will perform consistently according to specification. Validation is tedious, difficult, and costly, but it must be done to assure that the system is fit for use and is working according to specification. In addition to professional and licensing bodies, laboratories making blood products fall under the regulatory requirements of the Food and Drug Administration. The buyer of a system is responsible for verifying that the developer has complied with all regulations and that the software products are validated to an appropriate degree, that the hardware is certified to perform its designated functions, that an appropriate period of acceptance testing has been done and documented, and that the system in use performs to specification and is under control. CONCLUSION: System validation demonstrates to all concerned, inside and outside the laboratory, that the laboratory information system manages information well, with the expected accuracy and reliability, file integrity, auditability, and management control.

Clinical Laboratory Information Systems↗
PubMed1997

Ethnic differences in the length of the menstrual cycle during the postmenarcheal period.

In 1989, 125 African-American and 123 European-American girls aged 12-14 years were enrolled in a 2-year study in which they maintained a menstrual calendar, recording the date and amount of menstrual bleeding. Weight, exercise, and stress during the previous week were recorded at the start of each menstrual cycle. Although only minor ethnic differences were observed in expected cycle length (29.3 vs. 28.8 days for European-American and African-American girls, respectively), more prominent differences were observed in the between-subjects standard deviation of cycle length (2.9 vs. 2.2 days, respectively) and in the odds of having a cycle longer than 45 days (odds ratio=1.86, 95% confidence interval 1.17-2.97) for European-American compared with African-American girls. Low weight for height and high levels of exercise increased the probability of having a cycle longer than 45 days and decreased expected cycle length of 13- to 45-day cycles. Additional investigation of potential ethnic differences in menstrual cycle characteristics is warranted.

Adolescent↗
PubMed1997

Peroxynitrite inhibits leukocyte-endothelial cell interactions and protects against ischemia-reperfusion injury in rats.

Peroxynitrite (ONOO-) anion, formed by the interaction of superoxide with nitric oxide (NO), has previously been implicated as a cytotoxic agent. However, the effects of this free radical species on neutrophil (PMN)-endothelial cell interactions is largely unknown. We investigated the direct actions of ONOO- on PMN adhesion to endothelial cells in vitro and in vivo, as well as the effects of ONOO- on PMN-mediated myocardial ischemia-reperfusion injury. In vitro, peroxynitrite (100-1,000 nM) inhibited the adhesion of rat PMNs to the endothelium of isolated thrombin- or H2O2-stimulated rat mesenteric artery (P < 0.01 vs. thrombin or H2O2 alone). In vivo, in the rat mesentery, thrombin (0.5 U/ml) or N(G)-nitro-L-arginine-methyl ester (50 microM) significantly increased venular leukocyte rolling and adherence, which were also significantly (P < 0.01) attenuated by ONOO (800 nM) accompanied by reduced P-selectin expression on the endothelial cell surface. Isolated perfused rat hearts were subjected to global ischemia and reperfusion with rat PMNs (10(8) cells), which resulted in profound cardiac depression (i.e., a marked reduction in left ventricular developed pressure and maximal rate of development of left ventricular pressure). Infusion of ONOO- reversed the myocardial contractile dysfunction of ischemic-reperfused rat hearts to near baseline levels, and markedly attenuated the accumulation of PMNs in the postischemic heart. The present study provides strong evidence that nanomolar concentrations of ONOO- both inhibit leukocyte-endothelial cell interactions and exert cytoprotective effects in myocardial ischemia-reperfusion injury. Furthermore, our results suggest that the inhibition of P-selectin expression by peroxynitrite is a key mechanism of the modulatory actions of ONOO- on leukocyte-endothelial cell interactions.

Animals↗
PubMed1997

Cytochrome P450 genes from Helicoverpa armigera: expression in a pyrethroid-susceptible and -resistant strain.

The molecular basis of metabolic resistance to pyrethroids in Helicoverpa armigera is currently under debate. Substantial indirect evidence supports a role for both esterase- and cytochrome-P450-mediated metabolism. However, the relative roles played by these two mechanisms in field-based resistance is uncertain. Our understanding of the importance of P450-mediated metabolism is hindered by the paucity of cloned genes from this species, and the corresponding absence of data on rates of insecticide metabolism by functionally expressed P450s. To facilitate P450 gene isolation from H. armigera we used degenerate primers in the reverse transcriptase-polymerase chain reaction (RT-PCR) to clone P450 gene fragments from the RNA of a pyrethroid-resistant strain. Here we report the isolation of eight new P450 genes: seven from the CYP4 family and one CYP9. One of these genes, CYP4G8, is two-fold over-expressed in the resistant strain, whereas the other CYP4s showed either similar or undetectable levels of expression. CYP9A3 appears to be a homolog of the putatively resistance-associated CYP9A1 of Heliothis virescens. However, no difference in expression between the H. armigera strains was detected. CYP6B2, a gene previously reported to be over-expressed in a different pyrethroid-resistant strain of H. armigera, also revealed non-detectable levels of expression in both strains. These observations suggest that different P450s may be over-expressed in different resistant strains, and emphasize that recombinant expression will be necessary in order to define precisely their individual substrate specificities and ability to metabolize pyrethroids. The gene fragments described here represent an important first step in this direction.

Amino Acid Sequence↗
PubMed1997

Radiographic evaluation of breech presentation: is it necessary?

The purpose of this study was to evaluate the use of ultrasound in identifying fetal position and cervical spine flexion in breech presentations. Radiographic and ultrasonographic determinations of the type of presentation (frank, complete or incomplete) and degree of cervical spine flexion in 52 breech presentations were compared. The angle of flexion was defined as the angle between the fetal mandible and main axis of the cervical spine and categorized as full flexion, military, partial extension and full extension. Ultrasound was concordant with radiographic assessment of the type of presentation in 77% and the angle of flexion in 64% of the subjects and was even more accurate in those in labor. All cases predicted as having full flexion (< 90 degrees C) of the cervical spine by ultrasound had an angle of flexion < or = 90 degrees C on radiographic assessment. Of subjects in labor, ultrasound accurately identified the type of breech presentation in all cases. In addition, sonographic identification of full flexion of the cervical spine excludes cases of fetal neck extension and precludes the need for radiographic assessment prior to a trial of labor.

Adult↗
PubMed1997

P-selectin is up-regulated in vital organs during murine traumatic shock.

Murine traumatic shock is associated with increased adherence of neutrophils to the vascular endothelium resulting in neutrophil infiltration and tissue damage. We examined the effects of trauma on the expression of the adhesion molecule P-selectin in several vital organs (i.e., heart, lungs, liver, kidneys, and small intestine) 2 h after induction of Noble-Collip drum trauma in anesthetized rats. Total RNA was extracted from these organs and P-selectin mRNA was quantified by RNase protection assays. P-selectin mRNA was significantly increased over control nontraumatized, anesthetized rats in all vital organs (P<0.05 or less), with the largest increase occurring in the lung (P<0.01). Immunohistochemical analysis showed increased expression of P-selectin protein in postcapillary venules of all vital organs after trauma. To further investigate the possible mechanisms of increased P-selectin mRNA transcription promoter activity during trauma, we quantified binding of proteins from nuclear extracts to the kappaB site (-218GGGGGTGACCC[-207]) of the P-selectin gene by electrophoretic mobility shift assay. We confirmed the results of NF-kappaB binding by demonstrating increases in p50 and p52, as well as decreases in IkappaB in cytoplasmic and nuclear extracts from the lungs of trauma rats by Western blotting. Increased activity of the transcription factor, nuclear factor kappaB (NF-kappaB), occurred in all vital organs of the trauma rats compared to sham-operated controls. Our findings suggest that severe trauma results in up-regulation of P-selectin at the transcriptional level, which is partly controlled by an NF-kappaB-responsive element in the region of the P-selectin promoter. This increased activation of NF-kappB binding may contribute to the widespread increases in P-selectin expression observed in several vital organs 2 h after trauma, which in turn may play a key role in the pathogenesis of traumatic shock.

Animals↗
PubMed1997

Beneficial effects of C1 esterase inhibitor in murine traumatic shock.

Activation of the complement system is an integral part of the initiation and maintenance of the inflammatory process such as that occurring in traumatic shock, and is considered responsible for much of the trauma-induced microvascular injury. We investigated the effects of early complement blockade induced by a C1 esterase inhibitor (C1 INH) in a rat model of traumatic shock. Pentobarbital-anesthetized rats subjected to Noble-Collip drum trauma developed a shock state characterized by marked hypotension and a 83.3% mortality rate with a mean survival time of 157.5 +/- 26 min. Accompanying these effects were significant endothelial dysfunction and elevated intestinal myeloperoxidase activity. Treatment with C1 INH 15 mg/kg administered intravenously 10 min post-trauma, increases survival rate to 66.7% (p < .05), and prolonged survival time to 248 +/- 27 min (p < .05). C1 INH significantly preserved the endothelium-dependent relaxation to acetylcholine and attenuated the increase in myeloperoxidase activity in C1 INH-treated rats compared with untreated trauma rats (p < .05). Our results suggest that complement activation plays an important role in tissue injury associated with trauma, and that its inhibition at an early step in the complement cascade through a C1 esterase inhibitor is beneficial in rats experiencing traumatic shock. The mechanisms of the protective effect of C1 INH involves preservation of vascular endothelial function and diminished neutrophil accumulation leading to reduced neutrophil-mediated tissue injury.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1997

A molecularly cloned, pathogenic, neutralization-resistant simian immunodeficiency virus, SIVsmE543-3.

An infectious molecular clone of simian immunodeficiency virus SIVsm was derived from a biological isolate obtained late in disease from an immunodeficient rhesus macaque (E543) with SIV-induced encephalitis. The molecularly cloned virus, SIVsmE543-3, replicated well in macaque peripheral blood mononuclear cells and monocyte-derived macrophages and resisted neutralization by heterologous sera which broadly neutralized genetically diverse SIV variants in vitro. SIVsmE543-3 was infectious and induced AIDS when inoculated intravenously into pig-tailed macaques (Macaca nemestrina). Two of four infected macaques developed no measurable SIV-specific antibody and succumbed to a wasting syndrome and SIV-induced meningoencephalitis by 14 and 33 weeks postinfection. The other two macaques developed antibodies reactive in Western blot and virus neutralization assays. One macaque was sacrificed at 1 year postinoculation, and the survivor has evidence of immunodeficiency, characterized by persistently low CD4 lymphocyte subsets in the peripheral blood. Plasma samples from these latter animals neutralized SIVsmE543-3 but with much lower efficiency than neutralization of other related SIV strains, confirming the difficulty by which this molecularly cloned virus is neutralized in vitro. SIVsmE543-3 will provide a valuable reagent for studying SIV-induced encephalitis, mapping determinants of neutralization, and determining the in vivo significance of resistance to neutralization in vitro.

Amino Acid Sequence↗
PubMed1997

Lysophosphatidylcholine stimulates leukocyte rolling and adherence in rat mesenteric microvasculature.

Synthetic exogenous lysophosphatidylcholine (LPC) was used to induce leukocyte-endothelial cell interaction, utilizing intravital microscopy in the rat mesenteric microvasculature. Superfusion of the rat mesentery with 10 microM LPC significantly and time dependently increased leukocyte rolling and adherence compared with control rats. Moreover, LPC superfusion did not alter systemic blood pressure or mesenteric venular shear rate. Administration of either an anti-P-selectin monoclonal antibody (PB1.3 at 1 mg/kg i.v.) or a nitric oxide (NO) donor (CAS-1609, 10 microM superfusion) markedly attenuated LPC-induced leukocyte rolling and adherence (P < 0.01 from LPC alone). Immunohistochemical localization of P-selectin and intercellular adhesion molecule-1 (ICAM-1) expression on mesenteric venules was significantly increased after exposure to LPC compared with mesenteries superfused with phosphatidylcholine (P < 0.001). Flow cytometric analysis indicated that 10 microM LPC significantly (P < 0.05) increased P-selectin fluorescence on rat platelets. Furthermore, direct measurement of NO release from rat aortic vascular endothelium was significantly (P < 0.05) inhibited by 10 microM LPC. Thus LPC induces in vivo leukocyte rolling and adherence in the mesenteric rat microvasculature by increasing the surface expression of P-selectin and ICAM-1. Because inhibition of endothelial NO release promotes P-selectin expression, LPC-induced rolling and adherence may be mediated via reduced NO release.

Animals↗
PubMed1997

In-home oral anticoagulation therapy: a specialized program.

Recent years have seen an increase in the use of warfarin therapy to treat patients with atrial fibrillation and mechanical heart valves. Cardiovascular Home Care in Fort Worth, Texas, developed an in-home oral anticoagulation therapy program to improve patient outcomes, prevent adverse effects of therapy, and reduce cost and resource utilization.

Administration, Oral↗
PubMed1997

Patient-physician trust: an exploratory study.

BACKGROUND: Patients' trust in their physicians has recently become a focus of concern, largely owing to the rise of managed care, yet the subject remains largely unstudied. We undertook a qualitative research study of patients' self-reported experiences with trust in a physician to gain further understanding of the components of trust in the context of the patient-physician relationship. METHODS: Twenty-nine patients participants, aged 26 to 72, were recruited from three diverse practice sites. Four focus groups, each lasting 1.5 to 2 hours, were conducted to explore patients' experiences with trust. Focus groups were audio-recorded, transcribed, and coded by four readers, using principles of grounded theory. RESULTS: The resulting consensus codes were grouped into seven categories of physician behavior, two of which related primarily to technical competence (thoroughness in evaluation and providing appropriate and effective treatment) and five of which were interpersonal (understanding patient's individual experience, expressing caring, communicating clearly and completely, building partnership/sharing power and honesty/respect for patient). Two additional categories were predisposing factors and structural/staffing factors. Each major category had multiple subcategories. Specific examples from each major category are provided. CONCLUSIONS: These nine categories of physician behavior encompassed the trust experiences related by the 29 patients. These categories and the specific examples provided by patients provide insights into the process of trust formation and suggest ways in which physicians could be more effective in building and maintaining trust.

Adult↗
PubMed1996

Ethnic differences in the duration and amount of menstrual bleeding during the postmenarcheal period.

In 1989, 125 African-American and 123 European-American girls aged 12-14 years living in Durham, North Carolina, were enrolled in a 2-year study in which they maintained a menstrual calendar, recording the date and amount of menstrual bleeding. Weight, exercise, and stress during the previous week were recorded at the start of the menstrual cycle. Ethnicity was the strongest determinant of the duration of menstrual bleeding and of the probability of heavy bleeding. The mean duration of bleeding was 5.1 days for African-American girls and 5.6 days for European-American girls. Low body mass index, high stress, and dieting also influenced bleed duration, but the effects of low body mass index and stress were modified by ethnicity. european-American girls were less likely to have an episode of heavy bleeding (odds ratio = 0.48) than were African-American girls, while high stress increased the risk of having heavy bleeding episode (odds ratio = 1.51). Further investigation of potential ethnic differences in menstrual bleeding characteristics and of the role of stress in provoking heavy bleeding is warranted.

Adolescent↗