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Biomedical subjects

D Kent

Publications and source records attributed to D Kent.

At least 37 records · Page 2Linked to original sources
PubMed1993

Risk factors for complications of chronic anticoagulation. A multicenter study. Warfarin Optimized Outpatient Follow-up Study Group.

OBJECTIVE: To define risk factors for complications that occur during warfarin therapy. DESIGN: Retrospective cohort study. SETTING: Five anticoagulation clinics. PATIENTS: Nine hundred twenty-eight consecutive patients receiving 1103 courses of warfarin. MAIN OUTCOME MEASURES: Hemorrhagic and thromboembolic complications. RESULTS: In 1950 patient-years of follow-up, there were 1332 bleeding events (4 were classified as fatal, 31 as life-threatening, 226 as serious, and 1071 as minor). The cumulative incidence of fatal bleeding was 1% at 1 year and 2% at 3 years. The cumulative incidences of first episodes of life-threatening and serious bleeding at 1, 2, 4, and 8 years were 1%, 2%, 5%, and 9% and 12%, 20%, 28%, and 40%, respectively. Of 156 patients who had a serious or life-threatening hemorrhage, 32% suffered a recurrence, typically within 1 year. Independent predictors of a first episode of serious bleeding included a mean prothrombin time ratio (PTR) of 2.0 or more during the course of treatment (relative risk, 3.0; 95% CI, 1.9 to 4.7); recent initiation of warfarin therapy (relative risk during the first 3 months compared with the rest of the first year, the second year, and anytime thereafter, 1.9 [CI, 1.3 to 3.0], 3.0 [CI, 1.8 to 4.8], and 5.9 [CI, 3.8 to 9.3], respectively); variability of the PTR over time (relative risk for the highest compared with the lowest tertile, 1.6 [CI, 1.2 to 2.7]); and the presence of 3 or more comorbid conditions (RR, 1.4 [CI, 1.1 to 2.5]). Age, reason for anticoagulation, use of interfering drugs, and hypertension were not associated with risk for bleeding. The risk for a thromboembolic complication at a PTR of less than 1.3 was 3.6 (CI, 2.1 to 6.4) times higher than at a PTR of 1.3 to 1.5. CONCLUSIONS: The incidence of warfarin-associated bleeding may be reduced by attending to modifiable risk factors (that is, highly variable PTRs and values greater than 2.0), frequent monitoring early in treatment, and careful patient selection. Older age, in and of itself, is not a risk factor.

Adult↗
PubMed1993

A multiphase system bone implant for regenerating the calvaria.

The regeneration of bone with a biodegradable, biocompatible carrier and osteo-regenerative proteins may be possible if the carrier has the appropriate architecture to support osteoconduction and prevent soft-tissue prolapse into ablated bone segments. Using radiomorphometry and histomorphometry, our group assessed individually and combined the components of a multiphase system bone implant (MSI) in rabbit cranial defects (critical-size defects: CSDs): two disks of biodegradable polymer (PLG) and demineralized bone matrix (DBM), a recognized osteo-regenerative material. We used 48 rabbits evenly divided between four treatment groups and two time periods. Six weeks after treatment, both DBM and PLG had significant positive effects on bone regeneration (based on a three-factor analysis of variance, p < 0.05). These effects were synergistic when the components were combined (MSI). Defects treated with DBM or PLG alone continued to regenerate bone through 12 weeks. By this time, bone within the defects treated with MSI appeared to be maturing and consolidating. We conclude that the concept of placing osteo-regenerative factors between two biodegradable disks for regenerating segments of calvaria is viable.

Animals↗
PubMed1993

Comparison of four diagnostic systems for the diagnosis of somatization disorder.

This article compares the Feighner criteria, the DSM-III criteria for somatization disorder and a modified version of the proposed ICD-10 criteria. Working with a data set collected from the charts of 250 patients considered likely to have unexplained somatic symptoms, the kappa statistic and percentage agreement was calculated. The kappa between the DSM-III and DSM-III-R criteria is 0.93. Between the modified ICD-10 and DSM-III it was 0.71, but between Feighner and the modified ICD-10 it was 0.44. However, the different criteria identify the same patient population based on mental co-morbidity and demographics. The authors suggest that the modified version of the proposed ICD-10 should be investigated further, as it can use data sets previously collected for assessments of somatization disorder.

Adult↗
PubMed1992

Patient outcomes after lumbar spinal fusions.

OBJECTIVES: To determine success and complication rates for lumbar spinal fusion surgery, predictors of good outcomes, and whether fusion improves success rates of laminectomy for specific low back disorders. DATA SOURCES: English-language journal articles published from 1966 through April 1991, identified through MEDLINE searching (spinal fusion plus limiting terms), bibliography review, and expert consultation. STUDY SELECTION: Articles were selected only if they reported at least 1 year of follow-up data enabling the classification of clinical outcomes as satisfactory or unsatisfactory for at least 30 patients. DATA EXTRACTION: Two reviewers independently extracted data on patient characteristics, surgical methods, patient outcomes, and quality of study methods. DATA SYNTHESIS: Of 47 articles, there were no randomized trials. Four nonrandomized studies compared surgery with and without fusion for herniated disks; three found no advantage for fusion. On average, 68% of patients had a satisfactory outcome after fusion, but the range was wide (16% to 95%), and the satisfactory outcome rate was lower in prospective than in retrospective studies. The most frequently reported complications were pseudarthrosis (14%) and chronic pain at the bone graft donor site (9%). Clinical outcomes did not differ by diagnosis or fusion technique, but were worse in studies with a greater number of previously operated patients. CONCLUSIONS: For several low back disorders no advantage has been demonstrated for fusion over surgery without fusion, and complications of fusions are common. Randomized controlled trials are needed to compare fusion, surgery without fusion, and nonsurgical treatments in rigorously defined patient groups.

Adult↗
PubMed1991

Somatization and conversion disorders: comorbidity and demographics at presentation.

Although somatization disorder and conversion disorder are linked in DSM-III and DSM-III-R, they have very different histories. To directly compare these disorders, we reviewed the records accrued for 2 years at a large medical center and identified 65 somatization disorder patients and 51 conversion disorder patients. They differed substantially. The large majority (78%) of conversion disorder patients and nearly all (95%) of the somatization disorder patients were women. Ages at onset occurred throughout the life span among conversion disorder patients but mostly before the age of 21 among the somatization disorder patients. Somatization disorder patients were more likely to have had a history of depression, attempted suicide, panic disorder and divorce.

Adolescent↗
PubMed1989

Safety in transfusion practice. Is it safe to eliminate the major crossmatch for selected patients?

If a patient has no clinically significant unexpected antibodies, a major crossmatch is not required prior to blood transfusion so long as a test method that demonstrates ABO incompatibility is done. In this study, the safety of using a noncrossmatch method for detecting ABO incompatibility was compared with the use of an immediate spin crossmatch (ISCX). This noncrossmatch method consisted of the duplicate ABO testing of blood recipients, the repeated ABO testing of donor blood, and a clerical check to assure that only ABO matched or compatible blood was selected for transfusion. During the one-year study, 7124 patient samples were tested in duplicate for ABO, 26,942 U of red blood cells received from blood collection facilities were retested for ABO, and 23,962 U of blood selected for transfusion based on the noncrossmatch method were tested by an ISCX. ABO test results were concordant for 7115 of 7124 patient samples and discordant for nine. Seven of the nine discordant patient test results were resolved prior to transfusion, and two were inadvertently overlooked. ABO test results were concordant for 26,922 of 26,942 donor units and discordant for 20. Seventeen of the 20 discordant donor test results were resolved prior to transfusion and three were inadvertently overlooked. Two ABO incompatibilities were missed by the noncrossmatch method but were detected by the ISCX. Unless clerical errors can be totally eliminated, it may be safer to retain the ISCX.

ABO Blood-Group System↗
PubMed1987

Fetal death in motor vehicle accidents.

This study represents a series of cases of fetal death secondary to maternal involvement in a motor vehicle accident. During the period 1982 to 1985, nine cases were reported to the county coroner's office. In approximately 50% of the cases, other injuries to the victim, excluding injuries related to the pregnancy, were minor. Evidence of fetal distress was not always apparent at the time of initial evaluation. In all cases, placental abruption was documented. The injury mechanism was generally impact with the steering wheel. At the time of the accident, none of the patients were using seat belts. These cases demonstrate that minor maternal trauma without apparent maternal distress may result in fetal demise. The data indicate the need for prolonged continuous fetal monitoring for all pregnant women involved in motor vehicle accidents.

Accidents, Traffic↗
PubMed1986

Passive smoking.

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Humans↗
PubMed1986

Immunity to leprosy. III. The in vitro induction of B lymphocyte proliferation by mycobacteria.

The development of murine proliferative response assays has been initiated to begin to evaluate T-lymphocyte responses to the antigens of Mycobacterium leprae. In this study, M. leprae and 13 related strains of mycobacteria have been tested for stimulatory effects in proliferation assays using murine spleen, thymus or lymph node cultures. A number of mycobacteria were found to directly stimulate the proliferation of spleen and lymph node cells of all mouse strains tested including C3H/HeJ mice. Thymocyte cultures showed no response. The mitogenic effects of mycobacteria in spleen cultures were not dependent upon the presence of T cells or adherent cells, and resulted in the production of antibody-forming cells. Thus, these bacteria acted as polyclonal B-cell mitogens and could be readily distinguished from the lipopolysaccharide of Gram-negative bacteria by their mitogenic activity on C3H/HeJ spleen cells. The species of mycobacteria which exhibit direct mitogenic effects in spleen and lymph node cultures are a particular problem when specific immune responses to the antigens of these bacteria are compared. Such comparisons are necessary if in vitro assays are to be used to determine the nature of crossreactive antigens between M. leprae and other mycobacteria.

Animals↗
PubMed1984

Smoking and deaths.

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Death Certificates↗