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Biomedical subjects

K Benson

Publications and source records attributed to K Benson.

At least 19 recordsLinked to original sources
PubMed2005

Continued axillary sampling is unnecessary and provides no further information to sentinel node biopsy in staging breast cancer.

INTRODUCTION: Sentinel lymph node biopsy (SLNB) has become increasingly accepted as a diagnostic method to stage the axilla in breast cancer, selecting women with a positive sentinel node for completion axillary clearance. As SLNB became established, many surgeons supplemented SLNB to sample a minimum of four lymph nodes, on the assumption that the four-node technique is supported by randomised trial data. We hypothesised that the practice of undirected sampling to supplement SLNB adds little information to the status of the residual axilla. METHODS: One hundred and sixty-five patients with early breast cancer were studied. Following successful identification of the sentinel node, 84 women had completion axillary dissection and 81 women had an axillary sample with at least four nodes available for pathological assessment. RESULTS: Following successful identification of the sentinel node in 165 patients, the false negative rate (FNR) was 2/44=4.5% (95% CI 0.6-15.5), sensitivity 42/44=95.5% (84.5-99.4) and negative predictive value (NPV) 121/123=98.4% (94.2-99.8). In the axillary dissection cohort, the FNR was 2/26=7.7% (0.9-25.1), sensitivity 24/26=92.3% (74.9-99.1) and NPV 58/60=96.7% (88.5-100). In the axillary sample group, the FNR was 0/18=0% (0-18.5), sensitivity 18/18=100% (81.5-100) and NPV 63/63=100% (94.3-100). The SLNB was the only positive node in 12/26 (46.2%) in the axillary dissection group and 10/18 (55.6%) in the axillary sampling group. There was no patient in the axillary sampling group where the sample node was positive and the sentinel node negative. CONCLUSION: Once SLNB is validated within the multidisciplinary unit, undirected sampling of the axilla following identification of the sentinel node(s) is unnecessary. The additional sampling of non-sentinel nodes has no role to play either in the assessment of a potential false negative SLNB nor as predictive information on the status of the residual axillary nodes.

Adult↗
PubMed2001

Effects of electrochemotherapy with bleomycin on normal liver tissue in a rat model.

Preliminary studies that used electric pulses in vivo to facilitate entry of chemotherapeutic agents into tumour cells resulted in a 69% complete response rate for hepatocellular carcinoma in rats. This success motivated a focused investigation to define the adverse effects of this treatment on normal liver tissue. Bleomycin doses ranging from 0.5 to 2.5 U and electric fields from 500 to 2250 V/cm were investigated. Electrical treatment was administered using an array of six needles arranged in a circular pattern. Necrosis and four other histological parameters were examined 14 and 56 days after treatment. Results indicated that treatment effects were localised to the volume of treated tissue. These parameters, at both time points, were not significantly altered for liver tissue that was treated with all drug doses and electric fields of 1250 V/cm and below. Only the combination of more intense electric pulses with bleomycin produced adverse histological events in the form of localised liver necrosis at day 14. These effects were not visible at day 56. Liver function was normal through all of the treatment except for an elevation of several enzymes 1 day post-treatment.

Animals↗
PubMed2001

Treatment of hepatocellular carcinoma in a rat model using electrochemotherapy.

The effectiveness of antineoplastic agents has been augmented by applying pulsed electric fields directly to tumours after the administration of the drug. This treatment, known as electrochemotherapy (ECT), has been successful for cutaneous malignancies in animal models and in recent clinical trials. This study was aimed at investigating the applicability of ECT in a surgical setting for hepatocellular carcinomas induced in the livers of rats. Established tumours were injected with bleomycin, and electric pulses were then administered locally. Animals were followed based on tumour volumes and histological samples. Dose response data were obtained for both electric field intensity and bleomycin. Complete response rates for animals treated with electrochemotherapy ranged from 26.67% to 93.33 and were durable. In contrast, tumours that received no treatment, pulses only or drug only responded minimally. This supports the feasibility of using a ECT as a modality for treating hepatocellular carcinoma.

Animals↗
PubMed2001

Preschoolers' use of reflective properties: identification of reflections on partially transparent surfaces.

This exploratory study extended past studies of children's ability to reference the mirror as a tool in locating the source of reflected images to preschoolers' ability to use the affordances of a transparency. Thirty-six children (3.5 to 5 years old) were shown nonreflected lights and lights reflected on a partially transparent, glassy surface. Children did not spontaneously locate the source of the reflected image. However, they were able to verbally discriminate reflected from nonreflected images following training. These findings indicate that, although preschoolers may not spontaneously use transparencies as a perceptual tool, the ability to distinguish visual differences of reflected from nonreflected images on transparencies is likely within preschool children's developmental capacity.

Child Behavior↗
PubMed2000

A comparison of observational studies and randomized, controlled trials.

BACKGROUND: For many years it has been claimed that observational studies find stronger treatment effects than randomized, controlled trials. We compared the results of observational studies with those of randomized, controlled trials. METHODS: We searched the Abridged Index Medicus and Cochrane data bases to identify observational studies reported between 1985 and 1998 that compared two or more treatments or interventions for the same condition. We then searched the Medline and Cochrane data bases to identify all the randomized, controlled trials and observational studies comparing the same treatments for these conditions. For each treatment, the magnitudes of the effects in the various observational studies were combined by the Mantel-Haenszel or weighted analysis-of-variance procedure and then compared with the combined magnitude of the effects in the randomized, controlled trials that evaluated the same treatment. RESULTS: There were 136 reports about 19 diverse treatments, such as calcium-channel-blocker therapy for coronary artery disease, appendectomy, and interventions for subfertility. In most cases, the estimates of the treatment effects from observational studies and randomized, controlled trials were similar. In only 2 of the 19 analyses of treatment effects did the combined magnitude of the effect in observational studies lie outside the 95 percent confidence interval for the combined magnitude in the randomized, controlled trials. CONCLUSIONS: We found little evidence that estimates of treatment effects in observational studies reported after 1984 are either consistently larger than or qualitatively different from those obtained in randomized, controlled trials.

Bone Density↗
PubMed2000

An actigraphic comparison of sleep restriction and sleep hygiene treatments for insomnia in older adults.

We compared the efficacy of sleep restriction therapy combined with sleep hygiene, nap modification of sleep restriction therapy combined with sleep hygiene, and sleep hygiene alone as treatments for insomnia in 39 community-dwelling men and women 55 years and older. We used the wrist actigraph as an objective outcome measure for all subjects at baseline, end of treatment, and 3-month follow-up; polysomnography (PSG) was conducted in a subgroup of subjects. Although subjects appeared to follow restriction instructions through follow-up, we found few between-group differences in treatment efficacy. Lack of treatment effect might be explained by the efficacy of HYG as a treatment in itself and the relatively low symptom level in these healthy older poor sleepers. At baseline, actigraphic results were found to correlate more highly than sleep log data with PSG in our sample. Actigraphic total sleep time, in particular, was highly correlated with PSG.

Adult↗
PubMed1999

Isolation of CAG/CTG repeats from within the chromosome 2p21-p24 locus for autosomal dominant spastic paraplegia (SPG4) by YAC fragmentation.

Pure autosomal dominant spastic paraplegia (SPG) is a genetically heterogeneous neurodegenerative disorder of the central nervous system clinically characterized by progressive spasticity mainly affecting the lower limbs. Three distinct loci have been mapped to chromosomes 14q (SPG3), 2p (SPG4) and 15q (SPG6). In particular, SPG4 families show striking intrafamilial variability suggestive of anticipation and evidence has been provided that CAG/CTG repeat expansions may be involved. To isolate CAG/CTG repeat containing sequences from within the SPG4 candidate region, a novel approach was developed. Fragmentation vectors were assembled allowing direct fragmentation of yeast artificial chromosomes (YACs) with a short (> or = 21 bp) CAG/CTG sequence as the target site for homologous recombination. We used the CAG/CTG YAC fragmentation vectors to isolate CAG/CTG containing sequences from four YACs spanning the SPG4 candidate region between D2S400 and D2S367. A total of four CAG/CTG containing sequences were isolated of which three were novel. However, none of the four CAG/CTG repeats showed expanded alleles in two Belgian SPG4 families. In addition, we showed that the CAG/CTG alleles detected by the repeat expansion detection (RED) method could be fully explained by two polymorphic nonpathogenic CAG/CTG repeats on chromosomes 17 and 18, respectively. Also, the RED expansions in six SPG families could not be explained by amplification of the CAG/CTG repeats at the SPG4 locus. Together, our data do not support the hypothesis of a CAG/CTG repeat expansion as the molecular mechanism underlying SPG4 pathology.

Adenosine Triphosphatases↗
PubMed1998

Evaluation of changes in hemoglobin levels associated with ABO-incompatible plasma in apheresis platelets.

BACKGROUND: Hemolytic transfusion reaction is considered a rare complication of platelet transfusion. If minor ABO incompatibility exists (donor antibody directed against recipient's red cells [plasma-incompatible platelets]), however, the antibodies present in the plasma of platelets may cause acute hemolysis. A retrospective study was performed to identify possible hemolysis related to the transfusion of plasma-incompatible apheresis platelets. STUDY DESIGN AND METHODS: Acute hemolysis due to low-titer anti-A present in group O apheresis platelets transfused to a group A patient is reported. Pretransfusion and posttransfusion hemoglobin levels were evaluated in 16 non-group O autologous bone marrow transplant patients receiving apheresis platelets. All patients received, within 24 hours, both ABO-identical and plasma-incompatible platelet transfusions. No red cells were transfused during the time between the collection of the pretransfusion and posttransfusion hemoglobin samples. RESULTS: A total of 24 evaluable paired platelet transfusions in the 16 patients were compared. The mean change in hemoglobin following transfusion of the ABO-identical and plasma-incompatible platelets was -0.50 g per dL and -0.11 g per dL, respectively (p = 0.193). CONCLUSION: There was no significant change in the hemoglobin concentration associated with the transfusion of plasma-incompatible apheresis platelets (minor ABO incompatibility) in our study group. The case reported here represents the only hemolytic transfusion reaction identified among 46,176 platelet transfusions performed at this hospital, despite approximately 21 percent of all platelet transfusions being plasma incompatible. The risk of such a reaction remains low.

ABO Blood-Group System↗
PubMed1998

Nationwide survey of home transfusion practices.

BACKGROUND: Limited information exists on home transfusion practices. STUDY DESIGN AND METHODS: In 1995, a survey requesting data for 1994 was sent to 1273 American Association of Blood Banks (AABB) institutional members and 113 non-AABB home health care agencies that provide out-of-hospital transfusions. RESULTS: Of 943 respondents, 102 provide blood to a home transfusion program, 37 provide blood and run a home transfusion program, and 13 run a home transfusion program only, for a total of 152 (16%) with some involvement in home blood transfusions. Most of the 50 respondents with a home transfusion program are licensed by their state and accredited by the Joint Commission on Accreditation of Healthcare Organizations. All respondents have written policies for home transfusion, and 90 percent require a signed informed-consent document before initiating transfusions in the home. Most have policies requiring that there be a second adult and a telephone in the home, that the home be deemed safe for transfusion, that the patient's physician be readily available, and that the patient have had prior transfusions. The most common component issued by the blood providers was red cells, followed by platelets. White cell-reduced components were always provided by 36 percent of respondents. The most common patient diagnosis was cancer. Home transfusions were provided primarily by registered nurses. Only 14 percent of respondents indicated that the medical director of the blood bank is responsible for approving a patient for home transfusion. A posttransfusion visit is performed by 46 percent of respondents. CONCLUSION: Although most facilities have policies for the administration of home transfusions, there remains marked heterogeneity among blood providers and transfusionists regarding home transfusion practices.

Adult↗
PubMed1996

Developing a measure of patient perceptions of short-term outcomes of third molar surgery.

PURPOSE: The purpose of the study was to develop an instrument to measure patients' perceptions of their experiences after the removal of third molar teeth. METHODS: Nineteen patients (ages 18 to 25 years) who underwent surgical removal of four third molars after local treatment for mild symptoms of pericoronitis completed a newly developed 14-item instrument each evening for the 14-day period after surgery. A focus group was used to further examine the experiences of a subset of subjects. RESULTS: On the first day postsurgery, patients reported a median level of 81 on the 0 to 100 scale of "limitation of daily activity because of pain" (100 = total interference). This dropped to 21 by day 5, and all but two patients returned completely to normal activities by day 8. During the first 3 days, the median level of "average pain" ranged from 51 to 33 (100 = pain as bad as could be), and all but two patient were pain-free by day 10. Bad taste/breath persisted for between 2 to 4 days; food impaction was experienced by nearly all patients from days 3 through 14. Swelling was encountered by 10 of the patients for the first 2 days and was reported by only one patient after day 5. CONCLUSIONS: This study demonstrated that patients' perceptions of their experiences could be collected using a self-administered instrument, and it confirmed the changes in postsurgical morbidity that occur in healthy, young adults. This instrument and these data will be valuable to those striving to make informed decisions regarding third molar surgery.

Activities of Daily Living↗
PubMed1996

Hypotensive reactions: a previously uncharacterized complication of platelet transfusion?

BACKGROUND: In 1993, the American Association of Blood Banks (AABB) received reports of severe hypotensive reactions associated with platelet transfusions. The question arose as to whether these reports were indicative of a previously uncharacterized platelet transfusion reaction. STUDY DESIGN AND METHODS: To further characterize these reactions, the AABB Transfusion Practices Committee developed a series of three questionnaires. The initial questionnaire was sent to all AABB institutional members; the two subsequent questionnaires were sent to those institutions reporting severe and/or unusual platelet transfusion reactions. This report focuses on the 24 responses to the third and most detailed questionnaire, which specifically addressed reactions that were characterized by hypotension and/or unexplained respiratory failure. RESULTS: Of the 24 detailed responses received, 4 were not considered to represent unusual reactions to platelet transfusion, 3 described reactions consistent with a (presumably unrecognized) diagnosis of transfusion-related acute lung injury, and 17 described reactions that were primarily characterized by hypotension. The majority of the hypotensive reactions occurred within 1 hour of the beginning of the transfusion (88%), were associated with respiratory distress (82%), and resolved rapidly after cessation of the transfusion (82%). Eighty-eight percent of implicated components had been white cell reduced by filtration. CONCLUSION: The hypotensive platelet transfusion reactions that were described appear to represent a previously uncharacterized complication of platelet transfusion. However, the nature of the questionnaires used in this investigation does not allow the drawing of firm conclusions as to the frequency or the cause of these reactions.

Adolescent↗
PubMed1996

Patients' attitudes regarding out-of-hospital blood transfusion.

BACKGROUND: While the administration of blood transfusions outside of the hospital has become more prevalent, little is known about patients' attitudes regarding this practice. STUDY DESIGN AND METHODS: Twenty-nine adult patients who regularly received blood transfusions in a hospital's outpatient clinic and had never received home transfusions were surveyed. Linear analogue and categorical monetary scales were used to evaluate their responses to a series of questions. RESULTS: At the time of the survey, 27 study participants (93%) did not want home transfusions, and 21 (72%) thought home transfusions posed a greater risk than hospital based transfusion. More than half (56%) of the participants were unwilling to pay more for a home transfusion for themselves than for an outpatient hospital-based transfusion. Participants were willing to pay more for a home blood transfusion for a hypothetical patient requesting transfusions at home. The lack of available transportation and poor patient health were identified as important factors in determining how much more they would be willing to pay for transfusions at home. CONCLUSION: While blood transfusions at home may become more accessible, many patients may prefer to receive their transfusions in the hospital, probably because home transfusions are thought to pose a greater risk. A patient's health and the availability of transportation were determined to be important factors in decisions about how much more money to spend for transfusions at home than for those in an outpatient hospital setting.

Adult↗
PubMed1996

Monitoring for undertransfusion.

BACKGROUND: Most published reviews and audits of blood and blood component transfusion have focused on the issue of overtransfusion and on the inappropriate use of red cell components. There is growing concern that efforts to curb unnecessary transfusions may result in a trend toward undertransfusion of patients. There is little published information that addresses this issue or the magnitude of this practice. STUDY DESIGN AND METHODS: Undertransfusion was evaluated by examining the transfusion records from a 3-month period for 55 patients who met the study criteria of having either a hemoglobin level < 7 g per dL or a platelet count of < 10 x 10(9) per L. If the identified patient did not receive a transfusion within 24 hours of the reported hemoglobin level or platelet count, the medical record was reviewed by a resident physician. RESULTS: A total of 213 individual hemoglobin levels and platelet counts, representing the 55 patients, met our transfusion criteria. All except 8 of the identified patients received red cells and/or platelet transfusions. Reasons for not transfusing red cells included the patient's response to nutritional support and iron supplementation, refusal of blood, and noncompliance. Reasons for not transfusing platelets included falsely low platelet count because of platelet clumping in vitro, contraindication based on clinical diagnosis (e.g., immune thrombocytopenic purpura), and the patient's death before transfusion. CONCLUSION: Red cell and platelet transfusions were appropriately ordered for all patients who met the transfusion criteria. Undertransfusion is not a problem at this institution according to the criteria established. It is recommended that other institutions expand their blood utilization audits to include investigation for evidence of undertransfusion. Further research regarding the issue of undertransfusion is warranted and could be expanded to include other components.

Alcoholism↗