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Biomedical subjects

C Baker

Publications and source records attributed to C Baker.

At least 91 records · Page 5Linked to original sources
PubMed1993

The cost of not wearing seat belts. A comparison of outcome in 3396 patients.

Data from the North Carolina Trauma Registry were analyzed to determine the effect of seat belt usage on outcome in motor vehicle accidents. Of 6237 persons involved in motor vehicle accidents, data on seat belt usage were available for 3396. Of these, 1916 were not and 1480 were wearing seat belts. The mean hospital charge in belted patients was $10,500 +/- $18,200; and in unbelted patients, $15,250 +/- $26,300 (p < 0.001). The total hospital charges were $23 million for the 1508 patients not wearing seat belts. If the unbelted patients had outcomes similar to belted patients, the charges resulting from caring for the 1508 patients would have been $15.8 million, a potential savings of $7.2 million. There were 135 deaths among the unbelted patients (7.0%) and 47 deaths among the belted patients (3.2%) (p < 0.001). A similar projection of belted outcome for unbelted patients suggests that seat belt usage could have reduced the unbelted mortality rate by over one half. Patients wearing seat belts also had significantly shorter hospital stays, fewer days in the intensive care unit, and fewer days on the ventilator (p < 0.001). Seat belt usage is associated with a significant decrease in mortality rate, hospital charges, length of stay, intensive care unit stay, and ventilator requirements. Seat belts could have saved at least 74 lives and 7.2 million dollars during the period from October 1, 1987 to July 1, 1989 in patients seen in the seven trauma centers in North Carolina.

Accidents, Traffic↗
PubMed1993

Head CT scanning versus urgent exploration in the hypotensive blunt trauma patient.

In hypotensive blunt trauma patients with a diminished level of consciousness, it may be difficult to decide whether to proceed with immediate head CT scanning or urgent laparotomy or thoracotomy. The purpose of this study was to determine the frequency of emergency craniotomy and urgent laparotomy or thoracotomy in a group of 734 blunt trauma patients with initial hypotension (BP < 90 mm Hg systolic) admitted to the eight level I and II trauma centers in North Carolina. The mean initial systolic blood pressure was 64 +/- 26 mm Hg, and the mean Trauma Score was 8 +/- 5.8. Serious head injury (AIS head > or = 3) was present in 40% (293 of 734). Of 734 patients studied, 9.4% (69 of 734) died in the emergency department. Head CT scanning was performed on 47% (344 of 734) and produced positive results for 26% (202 of 734). Emergency craniotomy for intracranial hemorrhage was performed on 2.5% (18 of 734) (ten subdurals, three epidurals, and five other intracranial hemorrhages). Twenty-one percent (154 of 734) underwent urgent laparotomy, thoracotomy, or both. Overall hospital mortality for hypotensive blunt trauma patients was 36% (263 of 734). Although serious head injury occurs commonly (40%) in hypotensive blunt trauma patients, frequency of urgent laparotomy (21%) is 8.5 times greater than emergency craniotomy for intracranial hemorrhage (2.5%). This information may be used by trauma teams in prioritizing care for hypotensive blunt trauma patients.

Abdominal Injuries↗
PubMed1993

The comparison of patients suffering from temporomandibular disorders and a general headache population.

The purpose of this study was to examine the possible association of signs and symptoms of temporomandibular disorders relative to headache. Fifty-six sequential patients referred to the Headache Institute of Minnesota for evaluation and treatment of migraine and tension headaches were examined for signs and symptoms of temporomandibular disorders. The results of the examination of headache patients were compared to patients suffering from myofascial pain dysfunction and/or TMJ internal derangements from the TMJ and Craniofacial Pain Clinic at the University of Minnesota. Finally the migraine and tension headache patients were compared to each other and an asymptomatic population. Results indicate that patients with temporomandibular disorders exhibit significantly more jaw dysfunction and pericranial muscle tenderness than migraine and tension headache patients. Migraine and tension headache patients were found to have similar amounts of pericranial muscle tenderness. Migraine and tension headache patients exhibited significantly more pericranial and neck muscle tenderness than a general population.

Analysis of Variance↗
PubMed1993

Partial characterization of proteoglycans synthesized by human gingival epithelial cells in culture.

Proteoglycans (PGs) were extracted from the [35S]-sulfate labelled medium and cell layer of proliferating human gingival epithelial cells and analyzed by ion exchange and molecular sieve chromatography, and by SDS-PAGE. The majority of the incorporated radioactivity secreted into the medium eluted from a DEAE Sephacel ion exchange column as a single peak at 0.44 M NaCl with a small shoulder at 0.52 M NaCl. This material, when chromatographed on Sepharose CL-6B contained two species--a quantitatively major peak at K(av) = 0.30 (M(r) congruent to 235,000 on SDS-PAGE) and a quantitatively minor peak at K(av) = 0.39. The major peak was sensitive to alkaline borohydride, shifting to K(av) = 0.45, and nitrous acid degradation, indicating the presence of heparan sulfate PG with glycosaminoglycan chains with M(r) congruent to 26,000. The minor peak is chondroitin/dermatan sulfate PG with glycosaminoglycan chains of M(r) = 22,200 as indicated by sensitivity to alkaline borohydride (shifting to K(av) = 0.48) and chondroitin ABC lyase digestion. The [35S]-sulfate labelled material from the cell layer eluted in a broad peak between 0-0.50 M NaCl from DEAE Sephacel. Chromatography of this material on Sepharose CL-6B revealed the presence of three peaks at K(av) = 0.20, 0.31, and 0.75. The largest peak (K(av) = 0.20 and M(r) congruent to 245,000 on SDS-PAGE) shifted elution position to K(av) = 0.50 after alkaline borohydride treatment and was completely sensitive to nitrous acid degradation. These results indicate that this peak contains heparan sulfate PG with glycosaminoglycan chains of M(r) congruent to 20,000. Two peaks containing [35S]-sulfate labelled glycosaminoglycan chains were detected by chromatography of the cell layer extract over Sepharose CL-6B with K(av)S = 0.42 (M(r) congruent to 30,500) and 0.75 (M(r) congruent to 5300). The larger peak was predominantly chondroitin/dermatan glycosaminoglycan as indicated by susceptibility to chondroitin ABC lyase while the chains at K(av) = 0.75 were predominantly heparan sulfate with 83% susceptibility to nitrous acid. These results indicate that cultured human gingival epithelial cells synthesize and secrete principally heparan sulfate PGs with small amounts of chondroitin/dermatan sulfate PGs. This work will serve as a basis for future studies designed to examine those factors involved in regulation of PG synthesis by these cells.

Cells, Cultured↗
PubMed1993

Finding meaning in chronic illness as the key to self-care.

Self-care is an important element in the successful management of a long-term illness. However, people with chronic illnesses are often reluctant to adopt self-care behaviors. The purpose of this grounded theory study was to investigate the evolution of a readiness to self-manage a nonfatal chronic illness. A purposive sample of twelve individuals with a nonfatal illness whose course can be controlled by treatment were interviewed. In addition, the primary nurse caring for each informant at home was also interviewed. The findings indicate that the key process in self-care readiness was finding meaning in chronic illness. This process involved assenting to the illness and reframing its implications positively. It allowed informants to make sense of self-care teaching and to perceive themselves as self-care agents having some control over their illness course.

Adaptation, Psychological↗
PubMed1993

Injury severity grading in trauma patients: a simplified technique based upon ICD-9 coding.

UNLABELLED: The purpose of this study was to develop a simplified method of stratifying patient risk of death based on ICD-9 codes. METHODS: Data were obtained from a statewide trauma registry. A mortality risk ratio (MRR) was derived from a "training" subset by calculating a mortality rate for each ICD-9 code of interest. The independent variables of interest included TS, ISS, and MRRs (for the 1st & 2nd Dx, 1st op, & E code). RESULTS: (n = 37,100). When the 1st Dx and ISS were used as candidate variables in stepwise multivariate modeling, the MRR for the 1st Dx was the first variable to be entered into the model (1st Dx partial R2 = 0.37, ISS partial R2 = 0.02). CONCLUSION: This study shows that the 1st Dx is a better predictor of outcome than ISS. Since ICD-9 codes are more easily obtained and are better predictors of outcome, this study suggests that they may supersede the use of the ISS in injury severity scoring.

Adolescent↗
PubMed1992

Tyrosine kinase triggering in thymocytes undergoing positive selection.

Developing T cells undergo distinct selection processes that determine the T cell receptor (TcR) repertoire. One of these processes is positive selection. Positive selection involves the differentiation to mature T cells of thymocytes bearing TcR capable of recognizing antigens in the context of self-major histocompatibility complex (MHC) molecules. To study the potential involvement of tyrosine phosphorylation in the mechanism of positive selection, we have analyzed the activities of the tyrosine kinases pp56lck and pp59fyn in thymocytes expressing a unique TcR specific for HY antigen+ H-2 Db. Thymocytes undergoing positive selection displayed higher kinase specific activities of pp56lck and pp59fyn than nonselecting thymocytes. Furthermore, these increases in kinase activities were found only in the CD4+CD8+ subpopulation of thymocytes, where the selection process is believed to occur. These data suggest that tyrosine phosphorylation is part of the intracellular signals involved in MHC class I-driven positive selection from CD4+CD8+ immature thymocytes to CD4-CD8+ mature cells.

Animals↗
PubMed1992

Production and characterization of a polyclonal antibody to the c-erbB-3 protein: examination of c-erbB-3 protein expression in adenocarcinomas.

A polyclonal rabbit antibody was raised to the c-erbB-3 protein using a synthetic peptide corresponding to amino acids 1229-1241 of the predicted protein sequence of c-erbB-3. In Western blot analysis this antibody detects a single band at approximately 165 kD in a c-erbB-3 transfected (293/HER-3) human cell line. c-erbB-3 protein expression was then examined in a variety of adenocarcinomas. Expression of c-erbB-3 protein was indicated by membrane and/or cytoplasmic tumour cell immunoreactivity in formalin-fixed, paraffin-embedded tissue sections. c-erbB-3 protein was detected in a series of 13 out of 14 primary breast carcinomas, 3 of 5 gastric adenocarcinomas, 8 of 9 colonic adenocarcinomas, 2 of 9 prostatic adenocarcinomas, 0 of 6 renal cell carcinomas, 1 of 4 primary lung adenocarcinomas, and 5 of 7 endometrial adenocarcinomas. Immunohistochemical expression of the c-erbB-3 protein appears to be a relatively common event in adenocarcinomas, and further studies are now warranted to establish the role of the c-erbB-3 protein in neoplasia.

Adenocarcinoma↗
PubMed1992

A population-based, multivariate analysis of the association between 911 access and per-capita county trauma death rates.

STUDY OBJECTIVE: Decreased response times for injury should decrease the morbidity and mortality of trauma. The 911 telephone access is designed to improve the response time for emergencies. The purpose of this study was to analyze the association between county 911 access and per-capita county trauma death rates. METHODS: Data on all trauma deaths from 1986 through 1988 were obtained from the North Carolina Medical Examiner's data base. Counties were divided into those that had 911 access during the entire study period (15), those that never had 911 access (62), and those that installed 911 during 1987 (ten). Counties obtaining 911 access in 1986 or 1988 were excluded (13). RESULTS: The per-capita trauma death rate in counties that had 911 access throughout the study was 4.3 +/- 0.8 versus 5.0 +/- 1.1 per 10,000 population in counties that never had 911 access (P less than .01). Compared with counties with 911 access, counties without 911 were more rural, were less likely to have a trauma center, and were less likely to have advanced life support certification (P less than .03 for all). Controlling for these other factors, multivariate analysis demonstrated that 911 access had no significant independent association with per-capita county trauma death rates. In the ten counties that implemented 911 access in 1987, no significant change occurred in per-capita county trauma death rates after implementation of 911. CONCLUSION: Although counties with 911 access had lower trauma death rates by t-test, multivariate analysis showed no significant independent association of 911 access with per-capita county trauma death rates. In the ten counties that implemented 911 access in 1987, no significant changes in trauma death rates occurred after implementation. Although other factors may explain these findings, this study showed no significant independent impact of 911 access on per-capita county trauma death rates.

Emergency Medical Service Communication Systems↗
PubMed1992

Method slurring: the grounded theory/phenomenology example.

Increasingly, qualitative research methods are being embraced by nurse researchers because these approaches allow exploration of human experience. Failure to explicate qualitative methodologies is resulting in a body of nursing research that is either mislabelled or is classified broadly as qualitative and subject to charges that qualitative research lacks rigour. In this paper, the authors discuss the importance of specificity in methodology and distinguish between phenomenology and grounded theory, two frequently misused terms in the description of qualitative methodology.

Data Collection↗
PubMed1992

Neutrophil-mediated damage to human gingival epithelial cells.

Polymorphonuclear leukocytes (PMNs) have been implicated in the pathogenesis of inflammatory gingivitis and periodontitis. To further study the role of PMNs in mediating gingival injury, we cocultured these cells in vitro with monolayers of human gingival epithelial cells. Scanning electron microscopy revealed that the epithelial cells were homogeneous and SDS-PAGE/immunoblot analysis identified the presence of keratins K3, K13 and the K6/16 pair which authenticated the oral origin of the cells. Injury to the gingival cells was determined by scanning electron microscopy and measurement of cell detachment and cytolysis. Unstimulated PMNs produced minimal lysis or detachment, but PMNs stimulated by phorbol myristate acetate produced marked epithelial cell detachment without lysis, which was time- and PMN-dose-dependent. Supernatants of activated PMNs were similarly effective, indicating that the mediator was a stable soluble substance. Elastase and cathepsin G, two neutral proteases of PMN origin, produced time- and concentration-dependent detachment of gingival epithelial cells, suggesting that these enzymes may mediate this form of injury. In other studies, gingival epithelial cells were exposed to PMN myeloperoxidase (MPO), chloride and glucose plus glucose oxidase (GO) as a hydrogen peroxide (H2O2) generating system. The toxic oxygen species produced by this system caused lysis of the epithelial targets which was dependent on the duration of incubation and the concentrations of MPO and GO. Azide, an inhibitor of MPO, and catalase, a scavenger of H2O2, inhibited the lytic activity of this system. Scanning electron micrographs of gingival epithelial cells cocultured with activated PMNs showed lifting of the cells from the plating surface, while target cells attacked by the MPO system revealed extensive damage of cell membranes. These studies indicate that activated PMNs cause nonlytic detachment injury to gingival epithelial cells which may be mediated by digestion of their extracellular matrix by granule neutral proteases. Furthermore, PMN MPO is capable of generating toxic oxygen species which can lyse these epithelial cells. Collectively, these actions could have profound adverse effects on the function and integrity of the gingival epithelium.

Cell Death↗
PubMed1992

Proposed interpretive criteria and quality control parameters for ofloxacin susceptibility testing of Neisseria gonorrhoeae.

A multilaboratory study designed to determine the in vitro susceptibility criteria and quality control parameters for ofloxacin against Neisseria gonorrhoeae was conducted according to the guidelines of the National Committee for Clinical Laboratory Standards. Proposed susceptibility breakpoints are MICs of less than or equal to 0.25 microgram/ml for the agar dilution test and greater than or equal to 31 mm for the disk diffusion test. A category for resistance could not be defined. Proposed acceptable quality control MICs for N. gonorrhoeae ATCC 49226 and Staphylococcus aureus ATCC 29213 range from 0.004 to 0.03 microgram/ml and 0.25 to 1.0 microgram/ml, respectively. With 5-micrograms ofloxacin disks, acceptable inhibitory zone diameters for S. aureus ATCC 25923 and the N. gonorrhoeae control strains range from 22 to 27 mm and 43 to 51 mm, respectively.

Drug Resistance, Microbial↗
PubMed1992

Interpretive criteria and quality control limits for testing susceptibility of Neisseria gonorrhoeae to enoxacin.

For testing the susceptibility of Neisseria gonorrhoeae to enoxacin, a proposed susceptibility category includes strains for which MICs are less than or equal to 0.5 micrograms/ml and zones of inhibition are greater than or equal to 32 mm in diameter. Because of the sparcity of resistant gonococci, a resistance category was not defined, but laboratory-selected resistant mutants were appropriately categorized by the proposed criteria. A review of clinical data confirmed the utility of a single 400-mg oral dose of enoxacin for treating gonorrhea caused by strains judged to be susceptible by the proposed criteria. For quality control purposes, for N. gonorrhoeae ATCC 49226 MICs should be 0.016 to 0.06 micrograms/ml and zones of inhibition should be 43 to 51 mm in diameter.

Enoxacin↗
PubMed1991

The variability in activity of the universally expressed human cytomegalovirus immediate early gene 1 enhancer/promoter in transgenic mice.

Transcriptional control regions which direct transgene expression to all tissues in transgenic animals can be useful tools for gain-of-function experiments in transgenic animals. A candidate for this purpose is the regulatory region of the human cytomegalovirus immediate early 1 gene (HCMVIE1) which is highly expressed in many lines of tissue culture cells. Here we analyzed the activity of the HCMVIE1 enhancer/promoter using a sensitive reporter gene, the bacterial chloramphenicol acetyltransferase (CAT) gene. Three lines of transgenic mice with an intact transgene were established. All 3 lines expressed the transgene in all 28 tissues analyzed; however, levels of expression between the three lines varied up to 100,000 fold. In addition, expression levels in the high expressing line varied over a 10,000 fold continuum, while expression levels between tissues was almost uniform in the lowest expressing line. The transgene was well expressed in the high expressing line; CAT activity in the highest expressing tissues was equivalent to levels previously reported for tissue specific CAT transgenes active only in a limited number of tissues. These data support the utilization of the HCMVIE1 enhancer/promoter as a means of expressing a transgene in all tissues, but indicate that lines with substantially different overall levels of expression may be generated, and that markedly different levels of tissue specific expression may be found when the overall level of transgene expression is high.

Animals↗
PubMed1991

The spectrum of abdominal injuries associated with the use of seat belts.

Several recent reports have described abdominal injuries occurring as a result of seat belt use, raising concerns about seat belts as an agent of injury in motor vehicle crashes. The purpose of this study was to characterize the distribution of abdominal injuries after motor vehicle crashes in belted and unbelted patients admitted to trauma centers. The mortality was higher in unbelted than belted patients (7% vs. 3.2%, respectively, p less than 0.0001). Unbelted patients also had significantly more frequent and more severe head injuries (50.0% vs. 32.9%, respectively, p less than 0.001). The incidence of abdominal injury was equal in both unbelted patients (13.9%), but the spectrum of organs injured was different in the two groups. Gastrointestinal tract injuries (stomach, small bowel, colon and rectum) were significantly more frequent in belted vs. unbelted patients (3.4% vs. 1.8%, respectively, p = 0.001). The frequency of liver and spleen injuries was the same in both groups. This study demonstrates that in patients admitted to trauma centers after motor vehicle crashes, belted and unbelted patients have an equal incidence of abdominal injury, but belted and unbelted patients have a different spectrum of injuries. Hollow viscus injuries are more common in belted crash victims. Seat belt use was associated with significantly fewer head injuries and deaths. Physicians evaluating trauma victims after motor vehicle crashes should be aware of the fact that the types of abdominal injuries may vary substantially depending on seat belt use.

Abdominal Injuries↗
PubMed1991

Circulating anti-glomerular basement membrane antibodies in coeliac disease and epidermolysis bullosa acquisita.

The demonstration of circulating anti-glomerular basement membrane (GBM) antibodies is almost diagnostic for anti-GBM disease and Goodpasture's syndrome. These antibodies are, however, occasionally present in SLE and diabetes, in association with IgA disease and membranous nephropathy and after transplantation in Alport's syndrome. In addition, we describe circulating anti-GBM antibodies in a research worker who handled GBM and in whom coeliec disease later developed, and in an individual with epidermolysis bullosa acquisita. Neither patient had impaired renal function nor an abnormal urinary sediment, suggesting either that these antibodies were of low affinity, or that additional factors are required for the pathogenesis of an aggressive glomerular lesion when circulating anti-GBM antibodies are present. In at least one of these individuals anti-GBM antibodies may have developed after the exposure of basement membrane collagen type IV to activated immunological mediators and cells.

Adult↗
PubMed1991

Proposed interpretive criteria and quality control parameters for testing in vitro susceptibility of Neisseria gonorrhoeae to ciprofloxacin.

Ciprofloxacin was subjected to a multilaboratory study designed to determine its in vitro susceptibility criteria for Neisseria gonorrhoeae and its quality control parameters for both agar dilution and disk diffusion susceptibility testing for this species. All clinical isolates were susceptible, i.e., MICs were less than or equal to 0.06 microgram/ml and zones of inhibition were greater than or equal to 36 mm. A resistant category could not be defined, but in vitro-selected mutants gave zones of less than or equal to 35 mm, and MICs for these strains were greater than or equal to 0.12 microgram/ml. For quality control of ciprofloxacin agar dilution tests on supplemented GC agar, MICs for Staphylococcus aureus ATCC 29213 ranged from 0.12 to 0.5 microgram/ml. For quality control of 5-micrograms ciprofloxacin disk tests, N. gonorrhoeae ATCC 49226 and S. aureus ATCC 25923 produced acceptable zone diameter ranges of 48 to 58 mm and 22 to 26 mm, respectively.

Ciprofloxacin↗