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Biomedical subjects

R Patterson

Publications and source records attributed to R Patterson.

At least 37 records · Page 2Linked to original sources
PubMed2000

Review of alleged reaction to monosodium glutamate and outcome of a multicenter double-blind placebo-controlled study.

Monosodium glutamate (MSG) has a long history of use in foods as a flavor enhancer. In the United States, the Food and Drug Administration has classified MSG as generally recognized as safe (GRAS). Nevertheless, there is an ongoing debate exists concerning whether MSG causes any of the alleged reactions. A complex of symptoms after ingestion of a Chinese meal was first described in 1968. MSG was suggested to trigger these symptoms, which were referred to collectively as Chinese Restaurant Syndrome. Numerous reports, most of them anecdotal, were published after the original observation. Since then, clinical studies have been performed by many groups, with varying degrees of rigor in experimental design ranging from uncontrolled open challenges to double-blind, placebo controlled (DBPC) studies. Challenges in subjects who reported adverse reactions to MSG have included relatively few subjects and have failed to show significant reactions to MSG. Results of surveys and of clinical challenges with MSG in the general population reveal no evidence of untoward effects. We recently conducted a multicenter DBPC challenge study in 130 subjects (the largest to date) to analyze the response of subjects who report symptoms from ingesting MSG. The results suggest that large doses of MSG given without food may elicit more symptoms than a placebo in individuals who believe that they react adversely to MSG. However, the frequency of the responses was low and the responses reported were inconsistent and were not reproducible. The responses were not observed when MSG was given with food.

Animals↗
PubMed2000

Small bowel obstruction from internal hernia as a complication of colonoscopy.

After colonoscopy with polypectomy, a patient developed a surgically acute abdomen. Although abdominal radiology did not show free air, a presumptive diagnosis of bowel perforation was made and laparotomy performed. At the time of surgery the colon was normal, and there was no peritoneal contamination. A loop of ileum was discovered incarcerated into an internal paracecal hernia. The bowel was freed, and the operation was completed without need for resection. Several cases of incarcerated inguinal hernia resulting from endoscopy are described in the medical literature; this is the first reported case of an incarcerated internal hernia as a complication of colonoscopy.

Cecum↗
PubMed1999

Potential effect of the administration of substance P and allergen therapy on immunoglobulin E-mediated allergic reactions in human subjects.

Previously we observed and reported that immunoglobulin E-mediated (IgE-mediated) allergy in rhesus monkeys was decreased by the administration of substance P (SP) and an allergen. We extended these studies to human subjects, giving SP and 1 allergen to subjects with reactivity to more than 1 allergen, using reactivity to a second allergen as a control. SP and an allergen were initially given by aerosol delivery but subsequently were given by injection. The administration of SP and 1 allergen by aerosol delivery or injection resulted in decreased IgE-mediated reactivity to the allergen administered and also to the control allergen. This result occurred in 7 of 8 human subjects. The 2 initial subjects receiving 8 SP and allergen injections had a sharp reduction in their symptoms of ragweed hay fever lasting for 3 years to date. No significant reactions to the injection of SP occurred. Further controlled human research is necessary on the administration of SP and allergen and the mechanisms of action. Unexpected and serendipitous results first observed in rhesus monkeys and reproduced in allergic human subjects provide a new and potential mechanism for control and perhaps obliteration of common IgE-mediated allergies and even more-serious allergic problems.

Aerosols↗
PubMed1999

Occlusion contributes to temporal processing differences between crossed and uncrossed stereopsis in random-dot displays.

Stereoscopic depth discrimination was investigated in crossed and uncrossed directions using stimuli defined by binocular disparity differences embedded in dynamic random-dot stereograms. Across three experiments, fixation was directed to a point on the display screen (which placed crossed stimuli in front of and uncrossed stimuli behind, the background dots of the stereogram), to a point in front of the display screen (which placed both crossed and uncrossed stimuli in front of the background dots), and to a point behind the display screen (which placed both crossed and uncrossed stimuli behind the background dots). Results showed that depth discrimination was always good when the stimuli appeared in front of the background dots of the stereogram, whereas discrimination was always poor when the stimuli appeared behind the background dots. These results suggest that differences between crossed and uncrossed stereopsis as reported in past research arose, in part, from effects related to occlusion.

Depth Perception↗
PubMed1999

Stereoscopic (cyclopean) motion sensing.

This paper reviews literature on the motion processing of dynamic change in binocular disparity, called stereoscopic (cyclopean) motion. Studies investigating the visual processing of stereoscopic motion in the Z-axis, stereoscopic motion in the X/Y plane, and cyclopean motion are discussed. It is concluded that stereoscopic motion is processed by a motion-sensing system composed of special-purpose mechanisms that function like low-level motion sensors. For animals with binocular vision, low-level motion processing may involve, at least in part, stereoscopic processing.

Animals↗
PubMed1999

The stereoscopic (cyclopean) motion aftereffect is selective for spatial frequency and orientation of disparity modulation.

Across two experiments, this study investigated the spatial frequency tuning and orientation tuning (both in the disparity domain) of the stereoscopic (cyclopean) motion aftereffect. In Experiment 1, observers adapted to a moving stereoscopic grating of a given cyclopean spatial frequency and tested for the motion aftereffect with a static grating of the same or different spatial frequency. Robust motion aftereffects were induced only when the spatial frequency of the adapt and test stimuli was the same. In Experiment 2, observers adapted to a moving stereoscopic grating of a given cyclopean orientation and tested for the motion aftereffect with a static grating of the same or different orientation. Robust motion aftereffects were induced only when the orientation of the adapt and test stimuli was the same. Together, these results suggest that the stereoscopic motion aftereffect is tuned for cyclopean spatial frequency and orientation which, in turn, suggest that the stereoscopic motion aftereffect is mediated by low-level oriented spatial-frequency mechanisms.

Adaptation, Physiological↗
PubMed1999

Immunologic tolerability profile of celecoxib.

Celecoxib is primarily an inhibitor of cyclooxygenase (COX) 2 and, at therapeutic concentrations in humans, does not inhibit the COX-1 isoenzyme. The present meta-analyses explore the incidence of allergic reactions with celecoxib in patients in the North American and international arthritis trials, in patients with a history of hypersensitivity reactions to sulfonamides, and in patients receiving medications containing sulfonamides. Data were obtained from 11,008 patients in 14 double-masked trials of celecoxib in arthritis ranging from 4 to 24 weeks in duration. Results demonstrate that the incidence of allergic reactions with celecoxib was not statistically different from that seen with placebo or active comparators (nonsteroidal anti-inflammatory drugs [NSAIDs]) when data from the entire cohort were analyzed. The subset of patients with a history of sulfonamide hypersensitivity reactions had a 3-fold to 6-fold higher incidence of dermatologic reactions than did the entire arthritis trial cohort. Although dermatologic reactions occurred with greater frequency in patients with a history of sulfonamide hypersensitivity, the trend was consistent across all 3 treatment groups (celecoxib, NSAIDs, and placebo). According to these data and structural and metabolic differences between sulfonamides, the potential for cross-allergenicity between celecoxib and other sulfonamide-containing medications appears comparable to that of placebo and nonsulfonamide-containing NSAIDs. Additionally, the risk of allergic reactions with celecoxib appears comparable to that of placebo and comparator NSAIDs. Prospective trials are needed to confirm these findings.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1999

Rush immunotherapy in a dog with severe ragweed and grass pollen allergy.

BACKGROUND: Forty years of study of naturally occurring IgE-mediated allergy in animals is briefly reviewed. These studies provided models for study of bioactive mediators and innovative pharmacologic therapies for IgE-mediated asthma. OBJECTIVE: Based on our experience with canine allergy we evaluated and treated a dog with severe grass and ragweed allergy whose allergic dermatitis was uncontrolled by H1 blockers and topical corticosteroids. The dog was miserable during the Chicago grass and ragweed pollen seasons. METHODS: Rush immunotherapy was initiated during the ragweed season of 1997. RESULTS: Dramatic improvement was seen which persisted through the grass and ragweed seasons of 1998 after maintenance immunotherapy. CONCLUSION: The case is presented not as a model for canine immunotherapy but as an example of how animal research can be of value to both animals and humans.

Allergens↗
PubMed1999

Allergen immunotherapy: a long-term perspective.

Efficacy of standard IT to reduce medications and symptoms by at least 50% has been demonstrated multiple times. Reports of negative studies of IT deserve only evaluation of why the study design failed to demonstrate efficacy. Emphasis in the US and worldwide should be on education on the appropriate use of allergen IT, improvements in IT therapy, and preparation for the increased demand for allergists-immunologists as Fellowship training programs decline in numbers and individual training slots decrease.

Desensitization, Immunologic↗
PubMed1998

Cell-free hemoglobin preserves renal function during normothermic ischemia.

INTRODUCTION: The purpose of this study is to determine whether an infusion of polymerized hemoglobin solution is capable of suppressing the tubular damage and loss of renal function normally seen during a clinically relevant period of warm ischemia. METHODS: Male rats (350-450 g) were randomized to treatment with control (5% human serum albumin, HSA, n = 6) or test solution (9% polymerized hemoglobin, PHB, n = 6). Following a right nephrectomy, the left renal artery was perfused with 4 ml of HSA or PHB at 37 degreesC. The left renal artery was temporarily occluded for 50 min. At 72 h, creatinine (Cr), blood urea nitrogen (BUN), and percentage hemoglobin (Hb) were measured and the kidney was removed. Stained kidney sections were graded for ischemic injury (0-4, 0 = normal and 4 = necrosis of the proximal tubule). All results were expressed as means +/- SEM and statistical analysis was performed by t test. RESULTS: Treatment with PHB resulted in lower Cr (1.2 +/- 0.23 mg/dl vs 3.26 +/- 0.60 mg/dl, P < 0.01) and BUN (60.5 +/- 12.7 mg/dl vs 151 +/- 20.2 mg/dl, P < 0.01) at 72 h compared to HSA controls. Total hemoglobin was not significantly different at 72 h. The weight of all treated kidneys increased; however, the increase was significantly less in the PHB-treated group (34 +/- 9.1% vs 70 +/- 7. 4%, P < 0.01). PHB-treated kidneys had less evidence of histologic damage compared to those in the HSA group (0.75 +/- 0.11 vs 2.50 +/- 0.64, P < 0.05). CONCLUSIONS: During normothermic renal ischemia, renal artery infusion of PHB resulted in preservation of renal function and histologic architecture. PHB solutions may be useful in preserving organ function during prolonged periods of in vivo ischemia.

Animals↗
PubMed1998

The cyclopean (stereoscopic) barber pole illusion.

Across two experiments, this study found that the barber pole illusion (i.e. grating pattern appearing to move in the direction of the long axis of a rectangular aperture) is perceived with stereoscopic (cyclopean) motion. The grating and aperture comprising the barber pole display were created from binocular disparity differences embedded in a dynamic random-dot stereogram or from luminance differences. In Experiment 1, observers viewed a square-wave grating moving through a rectangular aperture of 2:1 or 4:1 aspect ratio and indicated whether the grating appeared to move in a direction perpendicular to its orientation or in the direction of the long axis of the aperture. For both stereoscopic and luminance stimuli equally, the grating appeared to move in the direction of the aperture (i.e. the barber pole illusion) more often with the larger aspect ratio than with the smaller aspect ratio. The condition for which a stereoscopic grating moved through a luminance rectangular aperture was also examined: the grating appeared to move in the direction of the aperture (inter-attribute barber pole illusion). In Experiment 2, observers viewed a square-wave grating moving through a rectangular aperture of 3:1 aspect ratio whose sides were indented in order to change the local direction of motion of the line terminators. For both stereoscopic and luminance stimuli, the grating appeared to move more frequently in a direction perpendicular to its orientation with the indented aperture (i.e. the illusion was diminished). Thus, local velocity signals from moving stereoscopic line terminators play a role in the production of the barber pole illusion similar to that of luminance motion signals. This suggests that the generation and propagation of motion signals at cyclopean levels of vision play a part in the representation of coherently-moving rigid surfaces.

Depth Perception↗