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Biomedical subjects

R Slaughter

Publications and source records attributed to R Slaughter.

At least 19 recordsLinked to original sources
PubMed2001

Coil embolization of iatrogenic arterio-venous fistula from pulmonary collateral artery to subclavian vein.

A young woman with surgically treated tetralogy of Fallot with pulmonary atresia, with multiple aorto-pulmonary collateral arteries, developed an arteriovenous fistula subsequent to transvenous insertion of an automatic implantable defibrillator via the left subclavian vein. The fistula extended between this vein and a systemic-to-pulmonary collateral artery arising from the subclavian artery. Unilateral peau d'orange, and painful congestion of the left arm and breast, ensued. These were cured by coil embolization of a fistula-related aneurysm.

Arteriovenous Fistula↗
PubMed2000

Women's steps of change and entry into drug abuse treatment. A multidimensional stages of change model.

The Transtheoretical, or Stages of Change Model, has been applied to the investigation of help-seeking related to a number of addictive behaviors. Overall, the model has shown to be very important in understanding the process of help-seeking. However, substance abuse rarely exists in isolation from other health, mental health, and social problems. The present work extends the original Stages of Change Model by proposing "Steps of Change" as they relate to entry into substance abuse treatment programs for women. Readiness to make life changes in four domains-domestic violence, HIV sexual risk behavior, substance abuse, and mental health-is examined in relation to entry into four substance abuse treatment modalities (12-step, detoxification, outpatient, and residential). The Steps of Change Model hypothesizes that help-seeking behavior of substance-abusing women may reflect a hierarchy of readiness based on the immediacy, or time urgency, of their treatment issues. For example, women in battering relationships may be ready to make changes to reduce their exposure to violence before admitting readiness to seek substance abuse treatment. The Steps of Change Model was examined in a sample of 451 women contacted through a substance abuse treatment-readiness program in Los Angeles, California. A series of logistic regression analyses predict entry into four separate treatment modalities that vary. Results suggest a multidimensional Stages of Change Model that may extend to other populations and to other types of help-seeking behaviors.

Adolescent↗
PubMed2000

Acceptable levels of digital image compression in chest radiology.

The introduction of picture archival and communications systems (PACS) and teleradiology has prompted an examination of techniques that optimize the storage capacity and speed of digital storage and distribution networks. The general acceptance of the move to replace conventional screen-film capture with computed radiography (CR) is an indication that clinicians within the radiology community are willing to accept images that have been 'compressed'. The question to be answered, therefore, is what level of compression is acceptable. The purpose of the present study is to provide an assessment of the ability of a group of imaging professionals to determine whether an image has been compressed. To undertake this study a single mobile chest image, selected for the presence of some subtle pathology in the form of a number of septal lines in both costphrenic angles, was compressed to levels of 10:1, 20:1 and 30:1. These images were randomly ordered and shown to the observers for interpretation. Analysis of the responses indicates that in general it was not possible to distinguish the original image from its compressed counterparts. Furthermore, a preference appeared to be shown for images that have undergone low levels of compression. This preference can most likely be attributed to the 'de-noising' effect of the compression algorithm at low levels.

Humans↗
PubMed1999

Activation and adoptive transfer of Epstein-Barr virus-specific cytotoxic T cells in solid organ transplant patients with posttransplant lymphoproliferative disease.

The treatment of Epstein-Barr virus (EBV)-associated lymphoproliferative disease (PTLD) in EBV seronegative solid organ transplant recipients who acquire their EBV infection after engraftment poses a considerable challenge because of underlying immunosuppression that inhibits the virus-specific cytotoxic T cell (CTL) response in vivo. We have developed a protocol for activating autologous EBV-specific CTL lines from these patients and show their potential use for immunotherapy against PTLD in solid organ transplant patients. Peripheral blood mononuclear cells from a panel of solid organ transplant recipients with and without active PTLD were used to assess EBV-specific memory CTL responses. The activation protocol involved cocultivation of peripheral blood mononuclear cells with an autologous lymphoblastoid cell line under conditions that favored expansion of virus-specific CTL and hindered the proliferation of allospecific T cells. These CTL consistently showed (i) strong EBV-specificity, including reactivity through defined epitopes in spite of concurrent immunosuppressive therapy, and (ii) no alloreactivity toward donor alloantigens. More importantly, adoptive transfer of these autologous CTLs into a single patient with active PTLD was coincident with a very significant regression of the PTLD. These results demonstrate that a potent EBV-specific memory response can be expanded from solid organ recipients who have acquired their primary EBV infection under high levels of immunosuppressive therapy and that these T cells may have therapeutic potential against PTLD.

Adoptive Transfer↗
PubMed1999

Scorpion toxins as tools for studying potassium channels.

The search for peptidyl inhibitors of K+ channels is a very active area of investigation. In addition to scorpion venoms, other venom sources have been investigated; all of these sources have yielded novel peptides with interesting properties. For instance, spider venoms have provided peptides that block other families of K+ channels (e.g., Kv2 and Kv4) that act via mechanisms which modify the gating properties of these channels. Such inhibitors bind to a receptor on the channel that is different from the pore region in which the peptides discussed in this chapter bind. In fact, it is possible to have a channel occupied simultaneously by both inhibitor types. It is expected that many of the methodologies concerning peptidyl inhibitors from scorpion venom, which have been developed in the past and outlined above, will be extended to the new families of K+ channel blockers currently under development.

Amino Acid Sequence↗
PubMed1999

Dimensions of health-related quality of life in persons living with HIV disease.

The purpose of this secondary analysis was to test empirically the influence of biological and physiological variables, symptom status, functional status, general health perceptions, characteristics of the individual and characteristics of the environment on overall quality of life in persons living with HIV disease. Path analysis, using multiple linear regression, was used to examine the fit between a health-related quality of life (HRQOL) theoretical model and data from a sample of 142 persons with an AIDS diagnosis. Thirty-two per cent of the variance in overall quality of life was explained by the HRQOL model with symptom status having the greatest influence (beta = -0.237, R2(Y x 2) = 5%). This analysis suggests that symptom status, functional status and general health perceptions are key dimensions of HRQOL. With a focus on prevention, health promotion, symptom management, and the alleviation of acute and chronic illness effects, HRQOL may be appropriate for capturing the outcomes of nursing interventions.

Adult↗
PubMed1997

Blockade of the voltage-gated potassium channel Kv1.3 inhibits immune responses in vivo.

The voltage activated K+ channel (Kv1.3) has recently been identified as the molecule that sets the resting membrane potential of peripheral human T lymphoid cells. In vitro studies indicate that blockage of Kv1.3 inhibits T cell activation, suggesting that Kv1.3 may be a target for immunosuppression. However, despite the in vitro evidence, there has been no in vivo demonstration that blockade of Kv1.3 will attenuate an immune response. The difficulty is due to species differences, as the channel does not set the membrane potential in rodent peripheral T cells. In this study, we show that the channel is present on peripheral T cells of miniswine. Using the peptidyl Kv1.3 inhibitor, margatoxin, we demonstrate that Kv1.3 also regulates the resting membrane potential, and that blockade of Kv1.3 inhibits, in vivo, both a delayed-type hypersensitivity reaction and an Ab response to an allogeneic challenge. In addition, prolonged Kv1.3 blockade causes reduced thymic cellularity and inhibits the thymic development of T cell subsets. These results provide in vivo evidence that Kv1.3 is a novel target for immunomodulation.

Animals↗
PubMed1993

Wound care practices in the United States.

Wound management is a crucial aspect of patient care and the nurse often is faced with the question of which approaches to use to provide an environment that supports healing and prevents complications. Important questions include how different types of wounds should be dressed, what method of debridement to use, whether dressings should be changed using sterile versus unsterile technique, and which adjunctive therapies to select under given circumstances. These topics are of interest to clinicians as they represent actual clinical practice and some of the major debates among health care providers who are trying to determine which practices to use to optimize wound healing. While studies are available that compare specific products, no data are available at this time regarding the current wound care practices in the United States. If data documenting the existing wound care practices were available, they would increase understanding of how other professionals manage wound care and provide the basis for planning patient care as well as educational programs and research on wound care.

Adolescent↗
PubMed1991

Paraneoplastic vasculitic neuropathy: a treatable neuropathy.

Paraneoplastic vasculitic neuropathy has been recently described. We report the first case of this disorder which responded both clinically and electrophysiologically to cyclophosphamide treatment. A 54-year-old woman with a history of metastatic endometrial carcinoma in remission had asymmetrical polyneuropathy, electrophysiological findings consistent with a diffuse axonal neuropathy, high sedimentation rate and spinal fluid protein, and microvasculitis with axonal degeneration on nerve biopsy. The patient was treated with 150 mg of cyclophosphamide daily with gradual clinical and electrophysiological improvement.

Action Potentials↗
PubMed1981

Evaluation of two methods for estimating theophylline clearance prior to achieving steady state.

The Koup et al. and Chiou et al. clearance estimation methods were evaluated n 19 chronic obstructive pulmonary disease (COPD)/asthmatic patients who were receiving aminophylline by continuous infusion. Estimated theophylline clearance (Clest) was determined using two serum concentrations obtained during the first few hours of therapy (1-16 hr) prior to achievement of steady state. Actual theophylline clearance (Clact) was determined after steady state conditions had been achieved (defined as 4-5 half-lives at the same infusion rate). The correlation between Clact and Clest was highly significant for both the Koup et al. and Chiou et al. methods, r = 0.865, p less than 0.001, and r = 0.858, p less than 0.001, respectively. The clearance estimation methods were compared with the Food and Drug Administration (FDA) dosage guidelines and shown to be clearly superior in predicting therapeutic steady state theophylline concentrations.

Aminophylline↗
PubMed1981

Suspected malabsorption of aminophylline in pancreatis.

The case of a patient with pancreatitis in whom low theophylline concentrations were observed on oral aminophylline is presented. Therapeutic theophylline concentrations were obtained with intravenous aminophylline. However, serum levels following oral doses were only 20 to 40% of those observed with intravenous administration, suggesting malabsorption. The most reasonable explanation for this was the patient's pancreatic dysfunction, since adequate absorption of oral aminophylline had been demonstrated on a previous admission not associated with pancreatis, and other possible causes of malabsorption were ruled out.

Administration, Oral↗
PubMed1979

Mechanisms of nonlinear disposition kinetics of sulfamethazine.

Five healthy male subjects received oral doses of 10 and 40 mg/kg of sulfamethazine (SMZ) approximately 14 days apart in a nonrandomized crossover study. Blood and urine samples were collected for at least 24 and 72 hr, respectively. All samples were assayed by the Bratton-Marshall procedure for SMZ and apparent N-acetylsulfamethazine (NSMZ). Recovery of total drug (SMZ + NSMZ) in urine was 88.9% following the low and 79.5% following the high dose. The low and high dose plasma concentration time curves were not readily superimposable (i.e., nonlinear kinetic behavior was observed). The data suggest that several mechanisms contribute to the nonlinearity. Specifically, a dose-dependent decrease in absorption rate displaced the plasma concentration-time curve to the right in some subjects, whereas apparent metabolic clearance (Clm) decreased with increasing dose (estimated assuming dose = amount of SMZ + NSMZ in urine to 72 hr) in all subjects (0.35 ml/min/kg for the low and 0.23 for the high dose). Still greater dose-dependent effects were found when apparent Clm of unbound drug was determined, since free fraction rose from 0.11 to 0.30 over the observed plasma concentration range. Renal clearance (ClR) of Smz appeared to be a complex function of time. In the low dose study it ranged from an average of 0.071 ml/min/kg at 2 hr to 0.146 ml/min/kg at 6 hr after drug. After the high dose comparable values were 0.083 and 0.128. Interindividual variability and pronounced nonlinear kinetics of SMZ after 40 mg/kg suggest that this dose is probably a poor choice for the determination of acetylator phenotype.

Acetylation↗