Acute Esophageal Necrosis in an Immunosuppressed Kidney Transplant Recipient: A Case Report.

Acute esophageal necrosis (AEN) is rare and characterized endoscopically by distal esophageal ulceration, blackening, and necrosis. It typically arises in patients with multiple comorbidities who have significant systemic disease and frailty. Specific precipitating events are variable. Evidence suggests a multifactorial etiology likely involving esophageal ischemia in the setting of corrosive injury from gastric contents and impaired tissue repair mechanisms. In the transplant setting, immunosuppression likely plays a substantial role. We report a case of AEN in a 70-year-old man following a renal transplant.

Reduced coronary NO production in conscious dogs after the development of alloxan-induced diabetes.

The role of nitric oxide (NO) in the control of coronary blood flow (CBF) during the development of diabetes is unknown. To study this, mongrel dogs were chronically instrumented using sterile techniques for measurements of systemic hemodynamics and CBF. With heart rate controlled (150 beats/min), veratrine (1-10 micrograms/kg) caused dose-dependent increases in CBF; e.g., 5 mirograms/kg of veratrine increased CBF by 57 +/- 7% from 41 +/- 1.3 ml/min (P < 0.05). The dogs developed diabetes 4-5 wk after injection of alloxan (40-60 mg/kg iv, blood glucose levels were 384 +/- 18 mg/dl). After diabetes the same doses of veratrine caused smaller increases in CBF; i.e., 5 micrograms/kg of veratrine increased CBF by 32 +/- 2% (P < 0.05 compared with control) from 28 +/- 4 ml/min. ACh- and adenosine-induced coronary vasodilation were reduced after diabetes as well. In anesthetized dogs after diabetes, vagal stimulation caused smaller increases in CBF. ACh and bradykinin caused smaller increases in NO(-)(2) production in coronary microvessels from diabetic dogs. Furthermore, despite the fact that mRNA for endothelial cell NO synthase from the aorta was increased twofold with the use of Northern blotting, the protein for aortic endothelial constitutive NO synthase was reduced by 66% after diabetes, as determined by Western blotting. Our results indicate that the NO-dependent coronary vasodilation by the Bezold-Jarisch reflex is impaired in conscious dogs after diabetes. The mechanism responsible for the impaired endothelium-dependent coronary vasodilation is most likely the decreased release of NO from the endothelium.

Clinical feasibility of a free-weight strength-training program for older adults.

BACKGROUND: An emerging trend in the field of gerontology is the recognition that older adults, especially the frail elderly population, can increase their levels of strength and thus improve functional capability. Social acceptance of physical frailty and provision of care and assistance to dependent persons has now turned to helping the frail elderly adults maintain or improve functional independence. METHODS: The purpose of our study was to show the feasibility and effectiveness of a low-cost strength-training program using free weights for increasing strength and functional fitness among older adult volunteers. Participants aged 73 to 94 years were residents of a multilevel care retirement community in Columbia, SC. The strength-training program, led by an instructor, used dumbbells and ankle weights and was conducted in a multipurpose recreation room at the retirement facility. RESULTS: Functional performance measures (timed chair stand, 6-meter walk, stair climb, balance) handgrip strength, and self-assessment of activity level were outcome measures. All 25 participants completed the strength-training program. The average program adherence rate of all participants was 87 percent. No participant injuries or other adverse effects were observed. Functional performance measures improved significantly among program participants, with the greatest improvement in the timed chair stand (33.5 percent improvement) and the stair climb (17.6 percent improvement). CONCLUSION: Free-weight strength-training programs are appropriate for older adults, can be implemented in community settings, and are associated with significant improvement in functional performance.

Patient and physician satisfaction with an outpatient care visit.

BACKGROUND: The purpose of this study was to identify factors contributing to patient and physician satisfaction during outpatient care visits, and to determine the degree to which physician and patient satisfaction are related. METHODS: The sample (N = 250) was drawn from the outpatient practice of the University of South Carolina Department of Family and Preventive Medicine. Opinions were obtained by self-administered written questionnaires for physicians and by interviews with patients conducted by second-year medical students. RESULTS: Most encounters (88%) were satisfying for the physician. Resident physicians reported greater satisfaction than did faculty. Physicians were most satisfied with encounters in which they believed they had adequate time, were competent to address patient problems, and communicated successfully with the patient. Patient satisfaction was high (78% highly satisfied). Patients were more likely to be fully satisfied if they believed themselves to be in good health, did not wait long, and had health insurance. Unperceived patient dissatisfaction was associated with waiting time and a belief that the physician did not pay attention. No relationship was found between patient satisfaction and physician satisfaction. CONCLUSIONS: The majority of patient care encounters were satisfying for both participants. The pervasive effect of waiting time on patient satisfaction emphasizes the need for careful scheduling. Lower satisfaction among faculty physicians should be explored to identify possible interventions to prevent physician burnout. Pressures from managed care organizations may decrease physician satisfaction if these take the form of reducing the time available for each patient or restricting physicians' ability to seek subspecialist consultation.

After-hours telephone calls in a family practice residency: volume, seriousness, and patient satisfaction.

BACKGROUND: After-hours calls are common in primary care physicians' practices. Calls may be unnecessary from the physician's perspective, but patients may have a different concept of the importance of reaching their physician immediately. This study's purpose was to compare physician and patient perceptions of the same telephone call episode. METHODS: Family practice residents (n = 19) recorded all patient-initiated after-hours telephone contacts (n = 192) during July 1993. Study personnel then telephoned, within 1 week of their call, the patients who made the calls. Patients were asked about the reason for their call, its seriousness, and their satisfaction with the handling of their problem. RESULTS: During the study month, 1.1 after-hours calls were received for every 10 office visits. A substantial minority of patients (29%) rated their problems in the highest severity category, while physicians assigned only 8% of calls the highest severity rating. The majority of patients (76.7%) were satisfied with how their after-hours calls were handled. CONCLUSIONS: In matched cases, physicians and patients perceive about the same proportion of calls to be routine versus more severe. Although patient satisfaction was high, further research into causes of dissatisfaction is needed.

Spatial adaptation to text on a video display terminal.

We employed vertical sinusoidal test gratings to search for spatial adaptation to lower-case text presented on a standard video display terminal. The parameters of the contrast sensitivity test were selected on the basis of waveform analysis of horizontal spatial luminance profiles of the text. We found that subjects exhibited a small (4-5 dB), but significant, frequency-specific spatial adaptation consistent with the frequency spectrum of the stimulus. The theoretical and practical significance of this finding is discussed.

Visual performance at video display terminals--effects of screen color and illuminant type.

A limited set of illuminants and phosphor colors are commonly used in video display terminal (VDT) working environments. This study attempts to identify any combinations of such conditions that influence performance on a visually demanding counting task. Experiments were performed to test whether the phosphor color, ambient lighting spectrum, or temporal frequency characteristics of the display and ambient lighting could alter performance. Under conditions where potentially contaminating variables such as reflectance level and screen glare patterns were equalized, no significant differences in performance were produced by the particular sets of stimulus conditions tested. The results suggest that displays and illuminant types that are in common use allow substantially equivalent visual performance.

Human electroretinogram responses to video displays, fluorescent lighting, and other high frequency sources.

Time-averaged human electroretinogram (ERG) responses were determined for several workplace visual stimuli which are temporally modulated at rates exceeding the perceptual critical fusion frequency (CFF). A clearly identifiable synchronous response was in evidence for a video display terminal (VDT) stimulus operating with a refresh rate as high as 76 Hz. A directly viewed fluorescent luminaire with controllable driving frequency elicited a synchronous response at rates as high as 145 Hz. In addition, an intense stimulus created by modulating the light from a slide projector produced responses at least as high as 162 Hz. The implications of these high-frequency responses are representing a potential basis for visual symptoms are discussed.

Saccadic suppression and stimulus uncertainty.

Saccadic suppression is a decline in detectability of a weak flash presented during a saccadic eye movement. We examined the hypothesis of Matin [Psychol. Bull. 81, 899 (1974)] that saccadic suppression may be due to increased stimulus uncertainty during the saccade. Uncertainty could arise from variability and inhomogeneities in the visual frame of reference translation that must accompany a saccade. We measured an average 0.6-log-unit suppression for a brief foveal 1 degree flash in a light-adapted detection task. Receiver-operating-characteristic (ROC) slopes for flash detection during saccades, compared with those when fixating, were reduced, indicating the presence of increased uncertainty. The magnitude of this uncertainty change was estimated and found to be consistent with that required to account for the measured detectability decline. When a flashed pedestal was employed to reduce the effect of uncertainty, there was no saccadic suppression and no ROC slope change. Also, spatially separate flashed markers, intended to reduce uncertainty, led to a significant reduction in saccadic suppression for one of two subjects. Our results are consistent with the hypothesis that a saccade leaves the observer with increased uncertainty as to which subjective visual direction to attend for a stimulus of fixed retinal locus. The magnitude of this uncertainty change can account fully for the saccadic suppression measured.

Location of nonlinear processes within the pupillary pathway.

The pupil oscillates in synchrony with a slow beat produced by adding two lights flickering at slightly different frequencies. This behavior shows that nonlinear processes are present within the pathway. To localize these processes, a light of one frequency was presented to one eye, while a light of a different frequency was presented to the other. No pupil oscillations were seen in response to the beat in these dichoptic conditions, but when both lights were superimposed and presented to the same eye a powerful pupillary response was produced. We conclude that the nonlinearity giving rise to the pupil's beat response occurs before the pathways from the two eyes join and hence is neural rather than muscular in origin. Furthermore, the lack of a pupil response in the dichoptic conditions suggests that the signals from the two eyes may combine linearly.

Effect of chromatic uncertainty on detectability of a visual stimulus.

The detectability of a brief color shift towards red or towards green of a foveally viewed yellow target is less by 25% if the observer is uncertain as to the direction of the color shift. This result matches a prediction of the theory of signal detectability: When signal parameters become uncertain, detectability declines.