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Biomedical subjects

C Campbell

Publications and source records attributed to C Campbell.

At least 163 records · Page 9Linked to original sources
PubMed1996

A phase III, multicenter, open-label, randomized, comparative study evaluating the effect of sevoflurane versus isoflurane on the maintenance of anesthesia in adult ASA class I, II, and III inpatients.

STUDY OBJECTIVE: To compare the clinical efficacy and safety of sevoflurane and isoflurane when used for the maintenance of anesthesia in adult ASA I, II, and III inpatients undergoing surgical procedures of at least 1 hour's duration. DESIGN: Phase III, randomized, open-label clinical trial. SETTING: 12 international surgical units. PATIENTS: 555 consenting inpatients undergoing surgeries of intermediate duration. INTERVENTIONS: Subjects received either sevoflurane (n = 272) or isoflurane (n = 283) as their primary anesthetic drug, each administered in nitrous oxide (N2O) (up to 70%) and oxygen (O2) after an intravenous induction using thiopental and low-dose fentanyl. The concentration of volatile drug was kept relatively constant but some titration in response to clinical variable was permitted. Comparison of efficacy was based on observations made of the rapidly and ease of recovery from anesthesia and the frequency of untoward effects for the duration of anesthesia in the return of orientation. Safety was evaluated by monitoring adverse experiences, hematologic and non-laboratory testing, and physical assessments. In 25% of patients (all patients 171 both treatment groups at selected investigational sites), plasma inorganic fluoride concentrations were determined preoperatively, every 2 hours during maintenance, at the end of anesthesia, and at 1, 2, 4, 8, 12, 24, 48, and 72 hours postoperatively. MEASUREMENTS AND MAIN RESULTS: Emergence, response to commands, orientation, and the first request for postoperative analgesia were all more rapid following discontinuation of sevoflurane than following discontinuation of isoflurane (sevoflurane, 11.0 +/- 0.6, 12.8 +/- 0.7, 17.2 +/- 0.9, 46.1 +/- 3.0 minutes, respectively, versus isoflurane, 16.4 +/- 0.6, 18.4 +/- 0.7, 24.7 +/- 0.9, 55.4 +/- 3.2 minutes). The incidence of adverse experiences was similar for sevoflurane and isoflurane patients. Forty-eight percent of patients on the sevoflurane group had no untoward effect versus 39% in the isoflurane group. Three patients who received sevoflurane had serum inorganic fluoride levels 50 microM/I. or greater though standard tests indicated no evidence of associated renal dysfunction. CONCLUSION: Sevoflurane anesthesia, as compared with isoflurane, may be advantageous in providing a smoother clinical course with a more rapid recover.

Adult↗
PubMed1996

A death in the family: household structure and mortality in rural Liaoning: life-event and time-series analysis, 1792-1867.

"Through a discrete-time life-event analysis of triennial household register data from a northeast Chinese village, Daoyi, between 1774 and 1873, we find that an individual's probability of dying, which we treat as an indicator of access to resources and the nature of household roles, was affected by the composition of their coresident kin.... Widows and widowers had higher mortality than the currently married. Orphans had higher mortality than children with at least one parent present. Reflecting the dependence of a wife's status on whether she had produced an heir for her husband, married women in young adulthood and middle age who had at least one son had substantially lower mortality than those without. Reflecting the strength of the claim that elderly males could make on household resources, children with coresident grandfathers had higher mortality than those without. Even though sons were supposed to be a form of old-age security, however, the death rate of the elderly was not reduced by the presence of sons and grandsons."

Age Factors↗
PubMed1996

Financial performance of safety-net hospitals in a changing health care environment.

Safety-net hospitals serving the poor and indigent in inner-cities have received inadequate research attention regarding the determinants of their financial performance in the changing health care environment. We analyze how the 1990-92 financial performance of 275 such hospitals is related to exogenous and endogenous factors such as payer mix, service mix, staffing and ownership. Models of hospital financial performance are developed using operating margin, cost per discharge and revenue per discharge as measures of performance. Stepwise regression is used to test the model with data from the American Hospital Association (AHA) and Health Care Investment Analysts (HCIA). Results suggest that: 1) The profitability of inner-city hospitals appears positively related with technical complexity of care; 2) High interest and low operating surplus may constrain the addition of technically sophisticated services to enhance profitability; 3) There is some evidence that new governmental programs, e.g. Medicaid managed care and Medicaid Diagnosis Related Groups (DRGs), may not have improved operating margins, though Medicaid DRGs appear to have contained costs. Follow-up research is needed on this issue; 4) Given external fiscal realities, internal management strategies for inner-city hospitals require research, e.g. developing appropriate managed care systems and timely expansion of sub-acute services and; 5) Services such as AIDS treatment and community health education represent opportunities to respond to community needs, especially since unit cost of such services will decline with high volume.

American Hospital Association↗
PubMed1996

Phase I/II trial of biweekly paclitaxel and cisplatin in the treatment of metastatic breast cancer.

PURPOSE: To determine the maximum-tolerated dose of escalating doses of paclitaxel (Taxol; Bristol-Myers Squibb, Princeton, NJ) administered biweekly with a fixed dose of cisplatin, to assess the toxicity, and to evaluate the activity of this combination in a phase I/II trial in metastatic breast cancer. PATIENTS AND METHODS: Twenty-nine women with metastatic breast cancer were enrolled; 27 were assessable for response and 29 for toxicity. All but two of the women had received prior adjuvant chemotherapy, with 23 receiving anthracyclines and six previous cisplatin. RESULTS: The initial starting dose of paclitxel 90 mg/m2 and cisplatin 60 mg/m2 became the phase II dose due to dose-limiting neutropenia. Responses were seen in 85% of assessable patients, with three patients (11%) achieving a complete response (CR) and 20 patients (14%) a partial response (PR), for an overall response rate of 85% (95% confidence interval [CI], 66% to 96%). The time to disease progression for patients who achieved a CR was 110 to 200 days, and for those with a PR, it was 96 to 377+ days, with a median time to progression of 7.1 months and a median response duration of 7.9 months. Sites of CR were skin, soft tissue, and lung, and all occurred in women with previous exposure to anthracyclines. Septic events were rare, with two grade 3 infections (7%), only one of which required hospital admission. There were no grade 4 nonhematologic toxicity and minimal grade 3 toxicity. A total of 251 chemotherapy cycles were given -- 16 with paclitaxel alone in five patients. Forty-five percent of patients required dose reductions, while 52% had delays due to neutropenia. CONCLUSION: Biweekly paclitaxel and cisplatin is an active combination in the treatment of metastatic breast cancer, including for patients with previous exposure to anthracyclines.

Adult↗
PubMed1996

Effects of a child abuse prevention unit in health classes in four schools.

The purpose of this study was to assess changes in parenting attitudes among high school students as an effect of a child abuse prevention unit taught in a required health class. Attitudes were measured using the Adult-Adolescent Parenting Inventory (AAPI), which was administered as a pretest-posttest. This was a primary prevention approach targeting students before they become parents. The unit consisted of an overview of child abuse, normal developmental expectations of children, anger management, and positive parenting techniques. Students from 4 schools participated in the study, and most students in the sample (N = 585) demonstrated healthy parenting attitudes. Low scores on multiple scales at pretest were recorded for 3.6% of the sample. Effect of intervention was measured using paired t tests, and a positive and statistically significant effect of intervention was noted, especially in 2 of 4 schools. Low-scoring students increased scores significantly although not up to mean pretest levels for the whole sample. Recommendations for further community health nursing research and educational initiatives are supported by these findings.

Adolescent↗
PubMed1996

Prevalence and impact of exposure to interpersonal violence among suburban and urban middle school students.

OBJECTIVE: The purpose of this study was to determine the prevalence of exposure to violence in preadolescent children in communities that vary by family income and to determine patterns of physical symptomatology and communication after exposure to a traumatic event. METHODS: Two hundred twenty-eight sixth-grade students from a suburban middle school (school A) and 209 sixth-grade students from an urban middle school (school B) in the Philadelphia metropolitan area were surveyed by a group-administered anonymous questionnaire. RESULTS: Two hundred two students (89%) from school A and 200 students (96%) from school B reported knowing someone who had been robbed, beaten, stabbed, shot, or murdered. One hundred twenty-nine students (57%) and 183 students (88%), respectively, witnessed a robbing, beating, stabbing, shooting, or murder. Ninety-one students (40%) and 141 students (67%) had been personally robbed, beaten up, stabbed, shot, or caught in gun cross fire. One hundred thirty-four (59%) and 152 (73%) reported hearing gunfire in their neighborhood. One hundred eighty-eight (82%) and 202 (97%) had at least one positive response in all three categories: knowing a victim, witnessing an event, and being a victim of violence. The proportion of positive responses from school B was significantly greater than the proportion from school A for all of these results. Many students reported symptoms associated with somatization syndromes, depression, and posttraumatic stress disorder; the school B group had significantly more symptoms than the school A group. Both student groups had discussed episodes of witnessing an event or victimization with others, mostly family members and friends, and expressed feelings of fear, anger, sadness, and frustration about these episodes. A very low percentage of the students (from 1% to 8% in the different analyses) consulted a medical or mental health professional. CONCLUSIONS: These data support a substantial prevalence or exposure to violence for suburban and, even more dramatically, for urban middle school-aged children. The higher-prevalence group reported a higher incidence of symptoms sometimes seen after traumatic stress. Many students in both groups expressed multiple feelings about their exposure to violence, and most talked to someone about their exposure; rarely was this person a health professional.

Chi-Square Distribution↗
PubMed1996

Breastfeeding and health in the Western world.

Considerable evidence suggests that infant feeding practices are associated with variations in health. This paper reviews research relating to the health of infants who receive breast milk, and of women who breastfeed, in the developed world. Obstacles to breastfeeding are examined, and current initiatives to increase breastfeeding levels are discussed.

Breast Feeding↗
PubMed1996

[Initial experience with the PCDiary: software for physicians for documenting and evaluating individual learning].

A computer diary was developed for physicians to create a portfolio of their self-directed learning. Each item of learning is recorded in the form of a question along with the stimulus, the learning resources used and the outcome planned for the learning. The records of 123 physicians which volunteered to use the diary were analyzed. Their response to the software, elicited by survey, is described. Items of learning were most often stimulated by scanning the literature and while seeking information to manage a patient. The physicians recorded their intent to change their practice as the outcome to learning most often when the learning was stimulated while managing a patient. One-half of the physicians reported that keeping the diary made them think about their patient care.

Attitude of Health Personnel↗
PubMed1995

Unequal homologous recombination of human DNA on a yeast artificial chromosome.

We examined unequal homologous DNA recombination between human repetitive DNA elements located on a yeast artificial chromosome (YAC) and transforming plasmid molecules. A plasmid vector containing an Alu element, as well as a sequence identical to a unique site on a YAC, was introduced into yeast and double recombinant clones analyzed. Recombination occurs between vector and YAC Alu elements sharing as little as 74% identity. The physical proximity of an Alu element to the unique DNA segment appears to play a significant role in determining the frequency with which that element serves as a recombination substrate. In addition, cross-over points of the recombination reaction are largely confined to the ends of the repetitive element. Since a similar distribution of crossover sites occurs during unequal homologous recombination in human germ and somatic tissue, we propose that similar enzymatic processes may be responsible for the events observed in our system and in human cells. This suggests that further examination of the enzymology of unequal homologous recombination of human DNA within yeast may yield a greater understanding of the molecular events which control this process in higher eukaryotes.

Base Sequence↗
PubMed1995

The effect of target site transcription on gene targeting in human cells in vitro.

We evaluate the effect of target site transcription on gene targeting in cultured human fibrosarcoma cells. A number of cell lines that harbored a plasmid recombination substrate within their chromosomal DNA were created. Gene targeting frequency was then measured at these different loci in the presence and absence of an agent that stimulated target site transcription. We observed that gene targeting was significantly enhanced by RNA transcription. The magnitude of transcription-stimulated gene targeting varied from 3-fold to > 20-fold. No increase in gene targeting was observed, however, when transcription proceeded away from, rather than through, the recombination site. Transcription-stimulated gene targeting was also observed when single-stranded plasmid vectors complementary to either the coding or template strand were used as recombination substrates. Our results indicate that gene targeting, like other forms of DNA recombination, can be stimulated by target site transcription. The implications of our observations on current models of transcription-stimulated recombination are discussed.

Binding Sites↗
PubMed1995

Cloning and mapping of a human gene (TBX2) sharing a highly conserved protein motif with the Drosophila omb gene.

We have identified and cloned a human gene (TBX2) that exhibits strong sequence homology within a putative DNA binding domain to the drosophila optomotor-blind (omb) gene and lesser homology to the DNA binding domain of the murine brachyury or T gene. Unlike omb, which is expressed in neural tissue, or T, which is not expressed in adult animals, TBX2 is expressed primarily in adult in kidney, lung, and placenta as multiple transcripts of between approximately 2 and 4 kb. At least part of this transcript heterogeneity appears to be due to alternative polyadenylation. This is the first reported human member of a new family of highly evolutionarily conserved DNA binding proteins, the Tbx or T-box proteins. The human gene has been mapped by somatic cell hybrid mapping and chromosomal in situ hybridization to chromosome 17q23, a region frequently altered in ovarian carcinomas.

Adult↗
PubMed1995

Cortical bone perfusion in plated fractured sheep tibiae.

The limited contact dynamic compression plate and partial contact plate were designed to decrease contact with cortical bone in an attempt to decrease cortical ischemia, remodeling, and eventual porosis under the plate after use of standard dynamic compression plates. This study quantified cortical bone blood flow beneath the plate with these three different designs in a sheep tibia fracture model. In 18 skeletally immature sheep, the right tibia was fractured and then was internally fixed with an interfragmentary screw and a dynamic compression plate, limited contact dynamic compression plate, or partial contact plate. At 12 weeks, cortical bone perfusion was assessed with laser Doppler flowmetry in nine areas beneath the plate. The baseline (before fracture) cortical bone cell flux averaged 100 +/- 60 mV. After fracture, this decreased to 60 +/- 48 mV (p < 0.0003); immediately after plating, the perfusion averaged 29 +/- 25 mV (p < 0.01). Cortical bone perfusion then increased to 106 +/- 52, 165 +/- 71, and 163 +/- 71 mV at 2, 6, and 12 weeks after fracture (p < 0.001 for all when compared with values after plating). No significant differences in cortical perfusion were seen between the types of plate. Cortical porosity under the plate was assessed with digital density analysis of microradiographs of this region. No significant difference was seen between the types of plate in this analysis or in biomechanical and disulphine blue perfusion analysis. Thus, no significant advantage was seen for the new plate designs used in this model. This lack of advantage may be a result of the immature animals used in the study, the protocol for blood flow measurement, the invasive periosteal stripping employed to create the fracture, or all three. However, as advantages with the new plate designs have been seen in other studies, this area warrants further investigation.

Analysis of Variance↗
PubMed1995

Clinical comparison of sevoflurane and isoflurane when administered with nitrous oxide for surgical procedures of intermediate duration.

The purpose of this study was to compare the haemodynamic effects and emergence times of anaesthesia with sevoflurane with those of isoflurane when the agents were administered with nitrous oxide to adult patients (ASA I and II) undergoing surgery of at least an hour in duration. Fifty patients were randomly assigned to receive either 0.65 minimum alveolar concentration (MAC) (1.3%) sevoflurane or 0.65 MAC (0.8%) isoflurane together with 60% nitrous oxide following induction with thiopentone, fentanyl, and succinylcholine. Systemic blood pressure and heart rate trends were similar for both groups for the duration of anaesthesia. However, differences in systolic blood pressure measurements were noted at one minute after incision (99 +/- 3 mmHg, mean +/- SE, in the sevoflurane group compared with 109 +/- 4 mmHg for isoflurane), and at emergence (125 +/- 3 mmHg for sevoflurane, 134 +/- 3 mmHg for isoflurane), and in diastolic blood pressure measurements at five minutes after intubation (64 +/- 2 mmHg for sevoflurane, 73 +/- 3 mmHg for isoflurane). Recovery of response to command was more rapid after discontinuation of sevoflurane-nitrous oxide (9.9 +/- 1.1 min) than after isoflurane-nitrous oxide (13.9 +/- 1.3 min). Despite earlier emergence, patients who had received sevoflurane did not request postoperative analgesia sooner. We conclude that the purported advantages of sevoflurane, namely haemodynamic stability and rapid emergence, can be expected even when the agent is administered at 0.65 MAC (1.3%) in nitrous oxide to a typical adult surgical population undergoing procedures of intermediate duration (2.3 +/- 0.2 hr).

Age Factors↗
PubMed1995

Alterations in diaphragm EMG activity during opiate-induced respiratory depression.

While opiate-induced increases in thoracic muscle tone may contribute to impaired ventilation during opiate anesthesia, the effects of high-dose opiates on diaphragm muscle activity have not been elucidated. The effects of the opiate agonist alfentanil (ALF, 500 micrograms/kg subcutaneously) on diaphragm (DIA) and intercostal (IC) electromyographic (EMG) activity in spontaneously ventilating adult rats were studied. EMG segments corresponding to inspiration and expiration were selected using an impedance plethysmographic respiratory waveform. Total EMG activity over a respiratory cycle was significantly greater in the DIA than in the IC. ALF produced a decrease in inspiratory and an increase in expiratory DIA EMG activity. These changes in diaphragm function following ALF were accompanied by significant respiratory depression. The effects of the alpha-2 agonist dexmedetomidine on ALF-induced changes in diaphragm and intercostal EMG activity were also examined. While dexmedetomidine alone had minimal effects on DIA activity, it significantly attenuated the ALF-induced increase in expiratory DIA EMG. The potential etiology and implications of these opiate-induced changes in diaphragm muscle function are discussed.

Alfentanil↗
PubMed1995

Marital fertility control among the Qing nobility: implications for two types of preventive check.

Demographers, as early as Malthus, have assumed that the preventive checks, delayed marriage and celibacy, were absent in traditional China. In this paper on the Qing (1644-1911) imperial lineage, we demonstrate that, instead, there may have been a different, more 'modern' preventive check: fertility control within marriage. Marital fertility of lineage couples during the eighteenth and nineteenth centuries was low to moderate. Such low fertility was the product of three behavioural mechanisms: late starting, early stopping and, most significantly, long spacing. Couples apparently regulated their fertility according to their economic resources and the sex of their surviving children. Moreover, they did so, we suggest, by regulating their coital frequency. Deliberate fertility control, in other words, was already within the 'calculus of conscious choice' for some Chinese well before this century. the speed of contemporary sinitic fertility transitions may accordingly be attributed to the fact that they did not require a change in attitudes, only the diffusion of new incentives and effective technologies.

Birth Intervals↗