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Biomedical subjects

A C Roth

Publications and source records attributed to A C Roth.

At least 19 recordsLinked to original sources
PubMed2001

Use of molecular markers to study the effects of environmental impacts on genetic diversity in brown bullhead (Ameirus nebulosus) populations.

Conservation biology needs sound biological information in order to maintain biological diversity in the face of the current rate of loss. An important component of the information needed is the level of genetic diversity within and between populations, especially for those species faced with exposure to environmental stressors. We applied multilocus DNA profile analysis (highly variable number tandem repeats [HVNTR] and randomly amplified polymorphic DNA [RAPD] techniques) and allozyme analysis to test whether individuals from historically degraded sites display levels of genetic diversity different from individuals taken from reference sites. Four Lake Erie tributaries, two impacted and two reference sites, were the sources of brown bullhead (Ameiurus nebulosus) samples. Pairwise comparison of the sampled populations demonstrated an association of decreased genetic diversity with exposure of brown bullhead to stressors using both RAPD and HVNTR analysis.

Animals↗
PubMed1999

Single-vessel arteriovenous revascularization of the amputated ear.

Successful single-vessel arteriovenous replantation of a completely amputated human ear is described. This result was followed by an experimental study using a rabbit model, to confirm that an amputated ear could survive replantation with only a single arteriovenous anastomosis. Fifteen animals were placed in one of two experimental groups: Group 1-arteriovenous replantation, no treatment (n = 6); and Group 2-arteriovenous replantation with medicinal leeching (n = 9). All ears demonstrated initial reperfusion of the replantation immediately following microanastomosis. Laser Doppler flow readings in the non-leeched replanted ears fell to zero by 8 hr and, by 12 hr, the non-leeched ears demonstrated signs of necrosis. All the leeched, replanted ears demonstrated perfusion and complete viability at the time of sacrifice. The case report, combined with the results from the experimental study, confirm that single-vessel arteriovenous replantation of an amputated ear is feasible.

Adult↗
PubMed1999

Digital images in the diagnosis of wound healing problems.

The use of digital wound images could allow remote consultation among patients, physicians, or other care-givers located at quite distant sites by means of the Internet. To evaluate the efficacy and validity of digital images for the evaluation of wounds, the ability and reliability of surgeons to diagnose and make treatment suggestions using digital images of several types of wounds were compared. Twenty-four wound images on 35-mm slides were selected for use in this study. Each slide image was digitized at 24-bit color with a resolution of 640 pixels horizontal by 425 pixels vertical and stored as a JPEG file. These images were then presented as a slide show on a video monitor, with resolution set at 640 x 480. Six physicians examined the images, first in digital format and later in the original slide form. Each observer assessed each wound and possible treatment options by filling out a questionnaire using a series of yes/no questions. For all observers, there was an 87 percent agreement between digital and slide images (p = 0.004). The agreement between the digital and slide images was measured for each individual observer using a kappa coefficient. The agreement level corresponded to the experience of the observer, with the kappa values ranging from greater than 0.8 (almost perfect agreement) for the attending plastic surgeon to just greater than 0.5 (moderate agreement) for the intern. With this study, the feasibility of distance wound consultation using digital images of a quality consistent with consumer-grade digital photography was demonstrated.

Feasibility Studies↗
PubMed1999

Role of the thromboxane A2 receptor in the vasoactive response to ischemia-reperfusion injury.

Neutrophil-endothelial adhesion in venules and progressive vasoconstriction in arterioles seem to be important microcirculatory events contributing to the low flow state associated with ischemia-reperfusion injury of skeletal muscle. Although the neutrophil CD-18 adherence function has been shown to be a prerequisite to the vasoconstrictive response, the vasoactive substances involved remain unknown. The purpose of this study was to evaluate the role of thromboxane A2 receptor in the arteriole vasoactive response to ischemia-reperfusion injury. An in vivo microscopy preparation of transilluminated gracilis muscle in male Wistar rats (175 +/- 9 g) (n = 12) was used for this experiment. Three experimental groups were evaluated in this study: (1) sham, flap raised, no ischemia (20 venules, 20 arterioles), (2) 4 hours of global ischemia only (19 venules, 22 arterioles), and (3) 4 hours of global ischemia + thromboxane A2 receptor antagonist (ONO-3708) (17 venules, 20 arterioles). ONO-3708 (5 mg/kg), a specific competitive antagonist of thromboxane A2 receptor, was infused at a rate of 0.04 ml/minute into the contralateral femoral vein 30 minutes before reperfusion. Mean arterial blood pressure was not changed at this dose of ONO-3708 (88 +/- 6 mmHg before infusion, 81 +/- 4 mmHg after infusion, n = 3). The number of leukocytes rolling and adherent to endothelium (15-sec observation) were counted in 100-microm venular segments, and arteriole diameters were measured at 5, 15, 30, 60, and 120 minutes of reperfusion. Leukocyte counts and arteriole diameters were analyzed with two-way factorial analysis of variance for repeated measures and Duncan's post hoc mean comparison. Statistical significance was indicated by a p < or = 0.05. The ischemia-reperfusion-induced vasoconstriction was significantly reduced by the thromboxane A2 receptor antagonist (ONO-3708). The mean arteriole diameters at 30, 60, and 120 minutes reperfusion were significantly greater in the treated animals than in the ischemia-reperfusion controls. Despite a significant increase in treated mean arteriole diameters, 30 percent of arterioles still demonstrated vasoconstriction. Neutrophil-endothelial adherence was not reduced by ONO-3708. Thromboxane A2 receptor blockade significantly reduces but does not eliminate ischemia-reperfusion-induced vasoconstriction in this model. This finding suggests that additional and perhaps more important vasoactive mediators contribute to vasoconstriction. Furthermore, thromboxane A2 receptor blockade has no effect on polymorphonuclear endothelial adherence.

Animals↗
PubMed1999

Effective audit trails--a taxonomy for determination of information requirements.

Current methods of detecting confidentiality breaches in electronic medical record systems are inadequate, partially due to the lack of necessary information at the point of audit trail analysis. In order to determine the information requirements for effective audit trail analysis, we have formulated a taxonomy of confidentiality breaches. By considering scenarios in which an inappropriate access might occur, we have identified "indicators" of confidentiality breaches, which may be thought of as evidence suggesting the possibility that a confidentiality breach has occurred. The collection of facts needed to describe the indicators provides insight into the types of information needed to improve confidentiality breach detection. Much of the information needed is unlikely to be available in the patient record. Research is needed exploring means of collecting and utilizing information from sources other than the patient record for use in improving patient information security.

Computer Security↗
PubMed1999

Using external data sources to improve audit trail analysis.

Audit trail analysis is the primary means of detection of inappropriate use of the medical record. While audit logs contain large amounts of information, the information required to determine useful user-patient relationships is often not present. Adequate information isn't present because most audit trail analysis systems rely on the limited information available within the medical record system. We report a feature of the STAR (System for Text Archive and Retrieval) audit analysis system where information available in the medical record is augmented with external information sources such as: database sources, Light-weight Directory Access Protocol (LDAP) server sources, and World Wide Web (WWW) database sources. We discuss several issues that arise when combining the information from each of these disparate information sources. Furthermore, we explain how the enhanced person specific information obtained can be used to determine user-patient relationships that might signify a motive for inappropriately accessing a patient's medical record.

Computer Security↗
PubMed1998

Effect of ketorolac tromethamine (Toradol) on ischemia-reperfusion injury in skeletal muscle.

The eicosanoids, leukotriene B4 (LTB4) and thromboxane A2 (TXA2), contribute to neutrophil adhesion and arteriole vasoconstriction, important microcirculatory events in ischemia-reperfusion (I-R) injury. The purpose of this study was to evaluate the effect of ketorolac on I-R injury of skeletal muscle. A videomicroscopic preparation of gracilis muscle in male Wistar rats (n=7) in two experimental groups was evaluated: Group 1-4 hr global ischemia only (19 arterioles, 19 venules), and Group 2-4 hr ischemia plus ketorolac (13 arterioles, 14 venules). Ketorolac (0.86 mg/kg, i.m.) was given 30 min prior to reperfusion. The number of neutrophils, rolling and adherent, was counted in 100-micron venular segments, and arteriole diameters were measured at 5, 15, 30, 60 and 120 min of reperfusion. The I-R-induced increase in neutrophil adhesion was significantly reduced by ketorolac, which significantly increased arteriolar vasodilation in the first 30 min of reperfusion and significantly reduced the I-R-induced vasoconstriction in arterioles at 30 min; this effect was lost at 1 hr of reperfusion. Although ketorolac augments immediate arteriole vasodilation and blocks subsequent vasoconstriction, this effect appears to be transient. These findings suggest that ketorolac may have potential as a treatment for I-R injury.

Animals↗
PubMed1998

Stimulation of angiogenesis to improve the viability of prefabricated flaps.

The cutaneous area in a prefabricated myocutaneous flap surviving after elevation is dependent on the rate and amount of vascular ingrowth that occurs from the underlying muscle. Two modalities, basic fibroblast growth factor and hyperbaric oxygen, were used separately and together in a prefabricated myocutaneous flap animal model to improve flap survival. The semimembranous muscle, based on the saphenous vessels of 40 female Wistar rats weighing between 250 and 325 grams, was tunneled under the ipsilateral abdominal skin and sutured in place. A 3 x 5-cm silicone sheet was placed beneath the muscle flap, and the ipsilateral epigastric vessels were ligated. Four groups of 10 animals each received one of the following treatment regimes: a 1-ml normal saline infusion into the saphenous arterial pedicle, a 1-ml infusion of basic fibroblast growth factor (1.0 microg/gm of muscle), a 1-ml normal saline infusion and 14 hyperbaric oxygen treatments, or a 1-ml basic fibroblast growth factor infusion and 14 hyperbaric oxygen treatments. After 1 week, the muscle, still based on the saphenous vessels, was elevated with a 3 x 5-cm abdominal skin paddle. The flap was sutured back in place, leaving the silicone sheet intact. The surviving area of each flap was measured 1 week later after it had demarcated into viable and necrotic regions. Laser Doppler skin perfusion measurements were taken before and after flap elevation and before animal euthanasia. Sixteen flaps, 4 in each group, were examined histologically for vascularity by means of hematoxylin and eosin staining. There was a statistically significant increase in flap survival area when either basic fibroblast growth factor or hyperbaric oxygen was used alone. Further improvement was noted with combination therapy. Histology confirmed improved vascularity in the basic fibroblast growth factor and hyperbaric oxygen-treated flaps. This study shows a significant and reliable increase in the area of prefabricated myocutaneous flap survival using either basic fibroblast growth factor or hyperbaric oxygen. There is a further complementary effect when these two modalities are combined, leading to near complete flap survival through improved vascularity.

Abdomen↗
PubMed1998

Diagnostic quality of low resolution images for tele-woundcare.

The use of digital wound images would allow remote consultation between patients, physicians, or other caregivers over the Internet. To evaluate the efficacy and validity of digital images for assessment of wounds, we compared the ability and reliability of surgeons to diagnose and make treatment suggestions using either digital or slide images of several types of wounds. Twenty-four wound images on 35-mm slides were selected for use in this study. Each slide image was digitized at 24-bit color with a resolution of 640 pixels horizontal by 425 pixels vertical, and stored as a JPEG file. Six physicians, of varying experience, examined the images, first in digital format and then later in the original slide form. Each observer assessed each wound for condition and possible treatment options by filling out a questionnaire using a series of yes/no questions. For all observers, there was an 87% agreement of answers between digital and slide images (p = 0.004). The agreement between the digital and slide images was also measured for each individual observer using a kappa coefficient. The agreement kappa correlated with the experience of the observer, with the kappa values ranging from greater than 0.8 (almost perfect agreement) for an experienced woundcare professional to just greater than 0.5 (moderate agreement) for a surgical intern. With this study, we have demonstrated the feasibility of distance wound consultation using digital images of a quality consistent with consumer-grade digital photography.

Diagnostic Imaging↗
PubMed1997

Ischemia-reperfusion injury in skeletal muscle: CD 18-dependent neutrophil-endothelial adhesion and arteriolar vasoconstriction.

The purpose of this study was to evaluate if the venular neutrophil-endothelial adhesion associated with ischemia-reperfusion of skeletal muscle is dependent on leukocyte adhesion glycoprotein CD18 function and to determine if this interaction influences the vasoactive response in nearby arterioles. An in vivo microscopy preparation of transilluminated gracilis muscle in 13 male Wistar rats was used for this experiment. Observations of nonischemic muscle (sham) demonstrated this preparation to be stable for 8 hours with negligible change in neutrophil adherence or arteriole diameter. Three groups were evaluated in this study: (1) sham, no ischemia, no treatment (n = 5, 20 arterioles. 20 venules), (2) 4 hours of global ischemia only (n = 4, 19 venules, 22 arterioles), and (3) 4 hours of ischemia plus monoclonal antibody against CD18 (n = 4, 12 venules, 9 arterioles). The murine monoclonal antibody (WT.3, Seikagaku America, Inc.), which binds the rat leukocyte function antigen I CD18 chain, was infused into the contralateral femoral vein 30 minutes prior to reperfusion. The number of leukocytes rolling and adherent to endothelium (15 seconds of observation) was counted in 100-microns venular segments, and arteriole diameters were measured at various times during reperfusion. All counts and measurements were normalized to baseline preischemic readings for each animal. Mean changes from baseline were compared between groups. The increase in ischemia-reperfusion-induced neutrophil-endothelial adherence in venules was blocked by monoclonal antibody, but rolling behavior was not changed. The ischemia-reperfusion-induced progressive vasoconstriction in arterioles was blocked by monoclonal antibody. These results suggest that (1) neutrophil-endothelial adherence function associated with ischemia-reperfusion in this model is CD18-dependent, (2) neutrophil rolling function does not appear to be dependent on CD18, and (3) neutrophil CD18 function is a prerequisite for ischemia-reperfusion-induced arteriolar vasoconstriction. These findings provide important mechanistic information that may help explain the deleterious microcirculatory events associated with ischemia-reperfusion injury skeletal muscle.

Animals↗
PubMed1997

A personal digital assistant for determination of fluid needs for burn patients.

In most instances, the treatment of major burn victims begins in the emergency room of the hospital closest to the accident site. It can be assumed that the emergency room personnel in most hospitals rarely see patients with major burns. Thus, their experience with burn fluid resuscitation is often limited. Yet it is critical that primary early treatment of burn injury with fluid resuscitation begin before the patient is admitted locally or transferred to a burn unit. To assist these individuals a fluid resuscitation calculation application has been developed to run on a hand-held personal digital assistant (Palm Pilot). This hand-held application is meant to assist in emergency situations where time is short, thoughtful computation is not possible, and a quick determination of fluid replacement therapy is important for the survival of the patient.

Adult↗
PubMed1996

Hyperbaric oxygen and cyclosporine as a combined treatment regimen to prevent skin allograft rejection in immunohistoincompatible mice.

Several previous studies reported various immunosuppressive effects of hyperbaric oxygen on nonspecific and specific cell-mediated reactions. A highly immunogenic skin allograft mouse model was used to evaluate the clinical relevance of the previously described immunosuppressive effects of hyperbaric oxygen. A 1.5 x 2.0-cm full-thickness skin allograft was cross-grafted between paired immunohistoincompatible mouse strains (N = 40, C57BL/6 and BALB/c female mice) that were randomly assigned to four groups receiving (1) no treatment (controls), (2) cyclosporine 1 mg per kilogram intraperitoneally daily, (3) cyclosporine plus a low-dose hyperbaric oxygen treatment (two treatments per day, once a week), and (4) cyclosporine plus a high-dose hyperbaric oxygen treatment (two treatments per day, three times a week) following surgery (N = 32). Allograft samples were taken from each group at day 9 after cross-grafting (N = 8). Skin allograft rejection was significantly delayed in all treatment groups compared to controls. No difference was found between animals who received cyclosporine only and the combined treatment regimen including low-dose hyperbaric oxygen. High-dose hyperbaric oxygen treatment in combination with cyclosporine substantially prolonged skin allograft survival compared to other treatments. These findings were histologically confirmed. We conclude that hyperbaric oxygen treatment as an adjunct to standard immunosuppressive therapy may only be advantageous if frequently applied.

Animals↗
PubMed1996

The effects of chronic ketorolac tromethamine (toradol) on wound healing.

Intramuscular ketorolac is a commonly used nonsteroidal anti-inflammatory (NSAI) agent for analgesia in surgical patients. Increasing numbers of surgical patients are chronically taking some form of an NSAI drug. We examined the effects of "chronic" intramuscular ketorolac on the healing of a closed linear surgical wound in the rat. Wistar rats were pretreated with 4 mg per kilogram per day ketorolac intramuscularly prior to receiving dorsal incisional wounds. The ketorolac treatment was continued and after 2 weeks the wounds were excised and separated with a tensiometer to measure mechanical properties. Breaking strength was directly measured, tensile strength was calculated, and collagen concentrations at the wound site were determined. A significant decrease in the mean breaking strength was seen in the ketorolac-treated animals when compared to controls. The ketorolac-treated animals had a mean tensile strength less than the controls, although this difference did not reach statistical significance. The mean collagen concentration of the ketorolac-treated wounds was significantly less than the untreated wounds. Use of ketorolac for just 1 week prior to surgery in rats produced a significant decrease in the breaking strength of their wounds. With the increasing use of ketorolac in surgical patients as well as the increasing use of oral NSAI drugs, more study of this effect is warranted.

Animals↗
PubMed1996

Nipple-areolar perfusion and reduction mammaplasty: correlation of laser Doppler readings with surgical complications.

Clinical assessment of nipple-areolar perfusion by color, capillary refill, and temperature during and after reduction mammaplasty is generally satisfactory. However, the estimation of vascular perfusion in patients with very large breasts or dark-skinned women is difficult. If marginal perfusion of the nipple-areolar areas is undetected, necrosis is likely. To this point, no studies have tested the ability of the laser Doppler perfusion monitor to give absolute alarm values that would suggest marginal perfusion in the nipple-areola following reduction mammaplasty. We therefore completed a prospective study of areolar perfusion during surgery and for up to 24 hours following reduction mammaplasty. Fifty-four patients were studied and data collected from 104 breasts. Laser Doppler perfusion was measured with a LASERFLO BPM2 Blood Perfusion Monitor (Vasamedics, St. Paul, Minn.). Perfusion values were recorded for each breast following anesthesia but prior to the incisions, at the end of surgery, and every 2 hours for 24 hours. Patients were divided into three groups according to their follow-up results: no complications (92 breasts), minor complications (9 breasts), and patients with tissue necrosis (3 breasts). The no complications group had a perfusion of 4.8 ml/min/100 gm following the reduction procedure, while the minor complications and tissue necrosis groups had average perfusions of 1.4 and 0.8, respectively, immediately after incision closure. The average tissue removed from each group was 811, 1171, and 2118 gm for the no complications, minor complications, and tissue necrosis groups, respectively. The results from this study suggest that a laser Doppler perfusion monitor could prove useful for monitoring areolar perfusion following reduction mammaplasty, especially in patients with extremely large breasts and/or dark skin. Our studies have shown that laser Doppler perfusion values that consistently are in the range of 1.0 to 2.0 ml/min/100 gm indicate marginal perfusion, and the recovery of these patients should be followed closely. Furthermore, patients with consistent perfusion values equal to or less than 1.0 coupled with other clinical signs of low perfusion should be considered for suture removal and/or free nipple graft.

Adult↗
PubMed1995

A model for recording the microcirculatory changes associated with standardized electrical injury of skeletal muscle.

The rate of major limb amputation following high voltage electrical injury remains high despite a decrease in mortality rate. Several theories about the pathophysiology of electrical injury have been discussed in the literature and different clinical regimens have been attempted to decrease the high amputation rate. However, to date, the overall tissue response after electrical injury remains incompletely understood with nothing new to offer these unfortunate patients. We have developed a rat gracilis muscle intravital microscopy preparation in order to better understand the mechanisms of this injury. A standardized 40-V stimulation of 10-sec duration was applied to the anterior belly of the gracilis muscle which translated into a current load of 30 mA. The current density was 750 mA/cm2. Sequential intravital assessment of microcirculatory changes before injury, as well as 5, 15, 30, 60, 120, 180 and 240 min after injury was performed. Consistent findings included initial cessation of blood flow in many capillary beds, focal flow reversal, venous and arterial vascular spasm. Restitution of microvascular flow varied from several minutes to 1 hr and was preceded by vasodilation at 5-15 min following the injury (+16.9 microns from baseline at 15 min). Starting at 30 min progressive vasoconstriction was noted (-0.8 micron from baseline at 30 min, -31.3 microns from baseline at 4 hr). High resolution observation of neutrophil behavior showed an increase in the number of these cells adherent to venular endothelium in areas exhibiting circulatory disturbances (+11.4 cells at 5 min, +15 cells at 4 hr). The standardization of this model allows a quantitative method of evaluating the microcirculatory changes associated with electrical injury and of studying ways to prevent tissue damage. The microcirculatory changes induced by electrical injury were similar to those reported in ischemia-reperfusion injury of skeletal muscle.

Animals↗
PubMed1995

Functional evaluation of peripheral-nerve repair and the effect of hyperbaric oxygen.

The effect of hyperbaric oxygen (HBO) on peripheral-nerve recovery following devascularization and repair was studied, using the rat sciatic-nerve model. The right sciatic nerve was mobilized, stripped of the extrinsic blood supply, transected, and repaired in an epineurial fashion, using microsurgical technique. Following repair, animals were randomized into one of two groups: 1) control--no HBO (n = 20); 2) HBO treatment--twice daily for one week (1.75 hr dives, 100 percent O2, 2.5 ATA) (n = 16). Nerve recovery was assessed weekly (total of 10 weeks) by walking-track analysis, from which the sciatic function index (SFI) was calculated for each animal. Mean SFI scores were improved in the HBO-treatment group over controls, becoming statistically significant at weeks 7 through 10. These results suggest that functional recovery in transected, devascularized, peripheral nerves may be improved by 1 week of HBO treatment following microsurgical repair.

Animals↗
PubMed1995

Mechanical leech therapy to relieve venous congestion.

When faced with venous insufficiency following replantation or free-tissue transfer, the surgeons' first choice is surgical repair. When repair is not possible, medicinal leeches may be applied to relieve congestion. However, leeches increase the possibility of infection through their gut contents, and there are times when the available leech supply is short and the need for rapid exsanguination is great. A mechanical device has been developed and tested which could be used as a substitute for the medicinal leech. Using a venous-congested rat epigastric flap, this device was demonstrated to be superior to a medicinal leech in restoring capillary perfusion to the flap during the first hour of exsanguination. The device may offer an alternative to the medicinal leech for the clinical treatment of small areas of tissue with venous congestion.

Animals↗