MR enhancing brain lesions in methanol intoxication

Methanol intoxication can cause necrosis of the putamen and subcortical white matter that is evident on neuroimaging. We report a 47-year-old man with significant methanol intoxication who had enhancing lesions in the caudate nuclei, putamina, hypothalamus, and subcortical white matter by MRI. This case demonstrates that contrast enhancement of brain lesions can be observed after methanol poisoning.

Asymptomatic pontine lesions found by magnetic resonance imaging: are they central pontine myelinolysis?

Clinicians occasionally receive radiographic reports noting pontine lesions in their patients who have undergone magnetic resonance imaging (MRI) for symptoms not referable to the pons. Based on these relatively isolated lesions, patients may receive the presumptive radiographic diagnosis of central pontine myelinolysis (CPM). Review of our MRI database from the last five years identified twelve such patients with hyperintense pontine lesions on T2-weighted scans which were out of proportion to supratentorial white matter disease processes and unexplained by the remainder of their radiographic studies. In an attempt to further clarify whether these findings were more consistent with CPM or some other process, we reviewed these patients' clinical records with particular attention to electrolyte disturbances, alcoholism, liver disease and hypertension. We also compared the MRI studies from these twelve patients with four MRI scans from patients with clinically diagnosed CPM and with eight post-mortem MRI scans on autopsy-proven asymptomatic CPM. By comparing pre- and post-mortem scans, five of the twelve unknown pontine lesions were felt to be too large to represent asymptomatic CPM. Five were thought to be incompatible with CPM based on shape and/or discohesiveness; one of these came to autopsy and showed cerebral and pontine ischemic rarefaction, not CPM. Only two of these twelve cases were felt to be asymptomatic or mildly symptomatic CPM, but have not come to autopsy. We conclude that pontine lesions found incidentally on MRI scans are a heterogeneous group, many of which are more consistent with pontine ischemic rarefaction than with asymptomatic CPM.

Induction of cross-reactive cytotoxic T-lymphocyte responses specific for HIV-1 gp120 using saponin adjuvant (QS-21) supplemented subunit vaccine formulations

The antigenic variation associated with Human Immunodeficiency Virus type-1 (HIV-1) envelope proteins could limit their utility in vaccines if the immune responses induced are specific for immunodominant variable epitopes. We evaluated the ability of experimental subunit vaccines, containing recombinant forms of the envelope glycoprotein (rgp120) from two HIV-1 variants, to induce immune responses capable of recognizing unrelated HIV-1 variants. A vaccine formulation based on HIV-1IIIB/LAI rgp120 and supplemented with saponin adjuvant (QS-21) induced neutralizing antibodies specific for the HIV-1IIIB/LAI variant. This antibody response was presumably specific for the variable principle neutralizing determinant (PND) of the third variable region of gp120, the V-3 region. This formulation induced cytotoxic T-lymphocytes (CTL) specific for the dominant V-3 epitope but also to an additional unidentified epitope outside of this region. The CTL specific for this second epitope also recognized gp120 from the HIV-1MN and HIV-1RF variants in a "cross-reactive" manner. A second vaccine formulation based on HIV-1MN rgp120 and QS-21 adjuvant induced neutralizing antibodies that were again variant-specific but also CTL that recognized all three HIV-1 variants in a cross-reactive manner. These data demonstrate that CTL capable of recognizing different HIV-1 variants, which are presumed to be specific for a conserved HIV-1 gp120 epitope, can be induced using subunit vaccines with the appropriate adjuvant while variant-specific antibody responses are produced. These findings support further evaluation of this vaccine format.

Neurobehavioral outcome in pediatric craniopharyngioma

Neurobehavioral dysfunction occurs in children with craniopharyngioma, both before and after treatment, and its impact on outcome may not be fully appreciated. Also unclear is whether neurobehavioral outcome relates more to tumor location or surgical factors. We reviewed the records of 20 children with craniopharyngioma who were seen between 1983 and 1995. All children had subfrontal craniotomy and either partial (14 children) or gross total (6 children) resection of their tumors. In addition to traditional neuropsychological testing, we assessed social behavior and school performance using standardized ratings based on family interviews and school records. Over a mean follow-up period of 38 months, only 3 of 20 children had a good outcome in all three categories, and 12 of 20 had moderate or severe impairment in at least one category. Outcome did not differ between those who had partial and those with gross total resection. We conclude that neurobehavioral disorders are common and cause important morbidity in children after treatment for craniopharyngioma. To evaluate these impairments in future outcome studies, standard neuropsychological testing should be supplemented by specific behavioral assessments to capture the full range of neurobehavioral disability. In this series, partial versus gross total resection did not influence outcome, implying that tumor location in diencephalic and limbic regions is a more important factor.

Ethics committees and quality improvement: a necessary link

As today's health care system undergoes dramatic changes, it becomes imperative that quality improvement efforts mesh with these changes to maintain quality outcomes in patient care. The confusing flurry of health care reform, cost containment, resource allocation, and advances in medical technology raises a variety of ethical issues. In the recent past ethics committees have been one strategy used to provide direction and support to care providers facing ethical dilemmas in clinical practice. The mutual goal of quality outcomes for the patient provides the rationale for linking quality improvement programs with ethics committees. As we move toward a more integrated and seamless health care system, this link may be critical to quality outcomes in caring for the patient from cradle to grave.

Diaphragmatic activity during REM sleep in the adult cat

Diaphragmatic electromyograms from five adult cats were studied to determine whether diaphragmatic activity, like central respiratory activity, increases in rapid-eye-movement (REM) sleep. Breaths with inspiratory durations between 250 and 2,000 ms were analyzed. 1) There was a greater slope of the moving time average of diaphragmatic activity in REM than in non-REM (NREM) sleep. These greater slopes occurred whether the route of breathing was through the upper airways or through an endotracheal tube and may have resulted from early recruitment of motor units. 2) Mean diaphragmatic activity was also greater, but other variables (peak activity, the area under the curve of diaphragmatic activity, mean intratracheal pressures, inspiratory airflow rates, and tidal volumes) were not greater in REM than in NREM sleep. 3) Diaphragmatic activity was similar in REM sleep and active wakefulness. 4) Across states, slope of the moving time average varied with the duration of inspiration: greater slopes were associated with shorter breaths. These results are consistent with an increase in central respiratory drive in REM sleep that increases the rate of rise of diaphragmatic activity.

Respiratory responses to tracheobronchial stimulation during sleep and wakefulness in the adult cat

The response to tracheal stimulation (50 microliters of tap water) during wakefulness, non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep was investigated in adult cats. In wakefulness, repetitive coughing occurred on 80% of the trials. In NREM and REM sleep, the most frequent response (approximately 69% and 58% of the trials, respectively) was arousal, followed by coughing. Apneas occurred following the stimulus and before arousal in 11% and 24% of the trials in NREM and REM sleep, respectively. In NREM sleep, the tracheal stimulus sometimes evoked expiratory efforts following a normal inspiratory effort (11% of the trials). These were much weaker than the expiratory efforts during coughing in wakefulness. In REM sleep, stimulation in 11% of the trials elicited increased inspiratory efforts. Although these may have been diminutive preparatory inspirations for coughing, they were much smaller than preparatory inspirations associated with coughing in wakefulness, and they were never followed by active expiratory efforts. Arousal from either NREM or REM sleep in response to tracheal stimulation was sometimes associated with an augmented breath. This response, which is common upon spontaneous arousal, may lead to deeper aspiration of the tracheal fluid. We conclude that in cats coughing requires wakefulness and that airway stimuli in sleep cause a variety of respiratory responses, some of which may be maladaptive.

Neither motor responses nor gastric emptying vary in response to formula temperature in preterm infants

The purpose of this study was to assess gastrointestinal responses to formula temperature in preterm infants. Healthy preterm infants were fed 4,250 KJ/l formula at 6, 24, and 37 degrees C. There was no significant difference in the magnitude of antral or duodenal motor responses among the three temperatures. All infants emptied approximately one third of the bolus feeding by 20 min, but there was no difference among the temperatures. Approximately 10-20% of a bolus feeding remained in the stomach 2 h postprandially, but there was no difference among the temperatures. Thermoreceptors do not appear to be functionally present in the preterm infant, suggesting that the benefit of feeding warmed formula to the preterm infant my have a limited physiological value.

Laparoscopic colon resection: 60 cases

The first 60 successfully completed laparoscopic colectomies in our series are reported. Patients used moderate amounts of narcotic postoperatively, tolerated oral intake early postoperatively (mean, 1.5 days), and returned to work 2.5 weeks postoperatively. Mean blood loss was 127 cc. Morbidity (11.6%) and mortality (1.6%) were acceptable. Length of stay, complications, and operating time all decreased with experience suggesting a steep learning curve.

Renal artery fibromuscular dysplasia: results of current surgical therapy

PURPOSE

This retrospective review describes current surgical management of renal artery (RA) fibromuscular dysplasia (FMD) to define contemporary clinical characteristics and surgical results in patients over the age of 21 years.

METHODS

From January 1987 through March 1994, 40 consecutive adults with hypertension had operative RA repair of FMD at our center and form the basis of this report. From histologic and angiographic appearance, FMD was classified with regard to specific type, noting the presence of RA dissections, RA macroaneurysms and branch RA involvement. Associations between blood pressure response to operation and patient age, duration of hypertension, presence of extrarenal atherosclerosis, presence of branch renal artery disease, and primary or secondary procedure were examined. Clinical characteristics and blood pressure response in these contemporary patients were compared with the results reported from an earlier surgical series.

RESULTS

Unilateral RA repair was performed in 34 patients, and bilateral procedures were required in six patients. Branch renal artery repair was performed in 28 instances, including ex vivo RA repair in 11 patients. There were no perioperative or follow-up deaths; however, three RA grafts (7%) failed within 30 days of operation. Initial blood pressure response was considered cured in 33%, improved in 57%, and failed in 10%. Analysis demonstrated that patients older than 45 years of age had a significantly decreased rate of hypertension cure compared with younger patients; among patients younger than 45 years of age, duration of hypertension was inversely related to cure. Compared with earlier surgical series, our current group of patients was significantly older, with more frequent branch renal artery involvement and extrarenal atherosclerosis, and demonstrated decreased rate of hypertension cure.

CONCLUSION

A beneficial blood pressure response is currently observed in most selected patients after surgical correction of RA-FMD. Compared with earlier series, however, the present day patient differs in many respects, including a significantly decreased chance for hypertension cure after surgical repair.

Acute arcuate fiber demyelinating encephalopathy following Epstein-Barr virus infection

We describe a patient who presented with an acute monophasic illness characterized by behavioral abnormalities, visual illusions, and a seizure, who had magnetic resonance- and brain biopsy-documented evidence of multifocal central nervous system demyelination. Serological studies were diagnostic of recent Epstein-Barr virus infection and included evidence of intrathecal synthesis of Epstein-Barr virus-specific IgG antibodies against the viral capsid antigen. Viral DNA could not be amplified from cerebrospinal fluid by polymerase chain reaction, and viral antigen and genome were not detected in the brain biopsy specimen. The patient's clinical course, diagnostic studies, and neuropathological findings all support the diagnosis of a postinfectious Epstein-Barr virus-mediated demyelinating encephalopathy.

Swallowing in sleep and wakefulness in adult cats

Clinical evidence indicates that swallowing, a vital function, may be impaired in sleep. To address this issue, we elicited swallows in awake and sleeping adult cats by injecting water through a nasopharyngeal tube. Our results indicate that swallowing occurs not only in non-rapid eye movement (NREM) sleep, but also in rapid eye movement (REM) sleep. In NREM sleep, the injections often caused arousal followed by swallowing, but, in the majority of cases, swallowing occurred in NREM sleep before arousal. These swallows in NREM sleep were entirely comparable to swallows in wakefulness. In contrast, the injections in REM sleep were less likely to cause arousal, and the swallows occurred as hypotonic events. Furthermore, apneas were sometimes elicited by the injections in REM sleep, and there was repetitive swallowing upon arousal. These results suggest that the hypotonic swallows of REM sleep were ineffective.