Brain stem glioma mimicking progressive basilar artery thrombosis.
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Biomedical subjects
Publications and source records attributed to G L Morris.
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Holstein calves were managed from less than 1 wk of age as in the special-fed veal industry but subjected to three dietary regimens (n = 10/group): low dietary iron (LI = approximately 5 mg iron/kg dry milk replacer) throughout 16 wk; 2) high then low dietary iron (H-LI = 140 mg/kg through d 18, then approximately 5 mg/kg through wk 16; a typical industrial scheme) or 3) high dietary iron (HI = approximately 105 mg/kg throughout the study). Several physiologic, behavioral and health indicators of welfare were monitored at various times. From wk 7 on, blood hemoglobin concentration was higher in HI calves than in LI, whereas that in H-LI calves was intermediate. Blood red cell count was higher in HI calves than in LI from wk 11 to 16, and was higher in HI than in H-LI from wk 14 to 16. Ratio of blood segmented neutrophils to lymphocytes (an indicator of stress) did not differ due to dietary regimen. Between wk 2 and 16, lying time increased from 69.5 to 76.6% of total time. Oral behaviors (e.g., licking and gnawing) occupied less than 15% of total time. Dietary regimen did not affect time spent either lying or engaging in oral behaviors. Calves in all dietary-regimen and slaughter-age groups experienced high frequencies of pneumonia, digestive-tract maladies and trichobezoars, but neither disease nor medical-treatment frequency was related to dietary regimen. Live, hot-dressed carcass and liver weights of the five calves/group slaughtered at 16 wk were not affected by dietary regimens, but carcass grade was highest for LI calves and lowest for HI.(ABSTRACT TRUNCATED AT 250 WORDS)
Evidence has accumulated rapidly to support the hypothesis that neurological anomalies underlie specific forms of learning disability (LD). This article reviews recent studies directed at the electrophysiological assessment of LD children, with emphasis on the brain stem evoked response(BSER) methodology. Child studies appear to indicate that there are significant differences in BSERs between LD and age-matched normal controls. The methodological and statistical differences among these studies, which have clouded the findings and made replication difficult, are reviewed. Improvements in sampling and empirical procedures are suggested, including the use of discriminant analysis to explore BSER asymmetries in LD children. Future inquiry into the measurement and analysis of BSER activity in LD populations is warranted on the basis of these preliminary findings. New information may bring professionals closer to an understanding of the neurological causes of specific subtypes of LD and permit earlier identification of these "at risk" populations.
Most research employing physiological stress profiling procedures has relied upon statistical analyses that are flawed in two ways: These analyses typically average the physiological levels observed across a series of observations during any one phase of the profile, thereby ignoring rate of change as a relevant parameter, and the problem of autocorrelation, or the natural correlation of time-series observations of the same physiologic activity, is unaddressed. We hope to introduce the biofeedback field to the technique of interrupted time-series analysis, which effectively deals with these two flaws. Interrupted time-series analysis additionally permits statistical conclusions based upon the stress profile of a single individual, thereby providing an objective basis for decisions concerning the effectiveness of training or the timing of changes in training for a single client. We describe the application of the technique to the analysis of a stress profile of a subject diagnosed as hypertensive.
In a 4-year period 168 tumor specimens received from 119 pediatric patients were plated in a soft agar cloning system. Overall, 47 or 28% of the tumor specimens had growth adequate enough for drug sensitivity testing. Drug sensitivity testing was performed using a variety of standards as well as investigational anticancer agents. Overall, 129 evaluable in vitro drug sensitivity tests were performed with 33 (26%) of the tests showing sensitivity to an agent. The most active drugs in vitro included the standard agents doxorubicin and cis-platinum as well as the investigational agents mitoxantrone and m-AMSA. From these data it is clear the cloning assay can be used to study pediatric malignancies. However, before the cloning assay can be applied to clinical pediatric oncology practice, the assay must be improved in terms of tumor growth and validated with prospective clinical trials.
Perinatal exposure to atmospheric carbon monoxide at sublethal concentrations affected neonatal piglets negatively. Low total hemoglobin concentration and oxyhemoglobin saturation ratio were present at birth in piglets farrowed by gilts that had been exposed to carbon monoxide at 250 ppm from gestation d 109 on, but stillbirth rate was only 4.8%. Carboxyhemoglobin saturation ratio increased from .0 to 19.8 and 22.4% as carbon monoxide concentration rose from background (less than 5 ppm) to 200 and 250 ppm. Carbon monoxide affected neonatal piglets' behavior. Piglets exposed to atmospheric carbon monoxide at 250 ppm perinatally took longer to nurse for the first time than did counterparts under background or 200-ppm concentrations. Those under carbon monoxide at 250 ppm had compromised performance in behavior tests that measured a piglet's ability to orient itself in, maneuver in and investigate its environment, respectively.
Atmospheric carbon monoxide at 200 ppm for 21 d had no adverse effect on any performance or behavioral characteristic measured in weanling pigs. The pigs tended to compensate for carboxyhemoglobin-induced reduction in oxygen-carrying capacity of their blood by increasing total hemoglobin concentration. Pigs exposed to carbon monoxide at 300 ppm had a 31% reduction in body-weight gain (.20 vs .29 kg/d) and a 20% reduction in feed conversion efficiency (gain/feed = .48 vs .60) at d 10. Over the 21-d exposure period, rate of gain was reduced by 21% (.31 vs .39 kg/d), feed conversion efficiency by 8% (.47 vs .51). There appeared to be a threshold concentration between 200 and 300 ppm above which atmospheric carbon monoxide reduced weanling pigs' performance.
Neuroepithelial development in Splotch mutant mouse embryos was examined using SEM and TEM. Unlike unaffected littermates, Sp/Sp embryos exhibited extensive neural tube closure defects, disorganization and misalignment of neuroepithelial cells in regions with open defects. Neuroepithelial cell processes often made lateral progress in these areas rather than maintaining their normal contact with the luminal surface. In addition, intercellular space was considerably increased and there were many ectopic cell processes in basal regions of affected areas. The role of altered cell-cell interactions in neurulation is considered.
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Studies of color pecking preferences in newly hatched chicks (Gallus domesticus) have shown unimodal preference in the orange region of the spectrum or bimodal preferences at blue and orange. In the present study, dark-harched White Leghorn chicks were tested in darkness with targets illuminated at 1 or 3 radiant intensity levels. Results showed the least amount of pecking at green (541 nm.) and peak preferences in blue-violet and orange-red regions. Findings were similar when other dark-hatched chicks were tested in the light (Experiment 2). Overall, findings suggest unlearned pecking preferences for short and long wavelengths, with minimums at green. Possible evolutionary and photochemical bases for such a bimodal wavelength preference function were discussed. Since bimodality was unaffected by target intensity and background, these variables probably do not account for the unimodal function reported by others.
The efficacy and tolerability of gabapentin therapy for seizures in patients in clinical practice were retrospectively evaluated. Demographics, seizure type and history, prior anticonvulsant therapy, concomitant anticonvulsant medications, gabapentin dosing, side effects, seizure response, and tolerability data were obtained from 100 consecutive clinical practice patients (47 men and 53 women) treated with gabapentin. All patients had been previously treated with a mean of 2.9 anticonvulsant drugs and were currently taking a mean of 1.75 anticonvulsant drugs. Seventy-two patients experienced a greater than 50% reduction in seizures, and 23 of these patients experienced a greater than 75% reduction; 57 patients continued gabapentin treatment, 5 of whom remain seizure free and side effect free with gabapentin monotherapy. Of the 42 patients discontinuing treatment, 17 had no seizure reduction, 17 had side effects, and 8 had both. One additional patient died. The mean daily dosage for all 100 patients was 2107 mg, and the mean daily dosage for patients who continued gabapentin treatment was 2270 mg. No linear relationship was found between dosage and patient weight. Fifty-two patients had the dosage of at least 1 concomitant anticonvulsant medication reduced, 31 had at least 1 concomitant anticonvulsant medication removed from the regimen, and 9 required a dosage increase of at least 1 anticonvulsant medication. Twenty patients experienced fatigue, which was usually transient after treatment initiation; in 13 patients fatigue was associated with carbamazepine therapy. In addition, 7 patients experienced ataxia (6 of whom were taking concomitant carbamazepine), and 2 experienced weight gain. Patients experiencing side effects resulting in discontinuation were taking a mean daily dose of gabapentin of 1182 mg. The maximum effective and tolerable daily dosage under clinical practice conditions appears to exceed dosages established in clinical trials. The results of our study suggest broader treatment parameters for gabapentin than initially determined in the more restrictive clinical trials conducted during the drug's development.
Functional magnetic resonance imaging (FMRI) detects signal changes in brain that accompany regional changes in neuronal activity. In normal human brain, FMRI shows changes in signal in the postcentral gyrus or superior temporal gyrus that correlate with voluntary motor activity or language processing, respectively. The model used to explain the changes in signal linked temporally with cerebral activity is a reduction in cerebral capillary deoxyhemoglobin concentration due to the increased blood flow that accompanies neuronal activity in the cerebrum. FMRI has been used in normal subjects but not extensively in patients. To determine the feasibility of using FMRI to map cerebral functions in patients with partial epilepsy syndromes, we performed a pilot study, using FMRI to identify signal changes in motor and language areas in response to tasks that activate those areas. Signal changes in epilepsy patients approximated those observed in volunteers. We conclude that FMRI can be developed as a method for functional cerebral mapping in partial epilepsies.
The clinical utility of 16 channel computer-assisted out-patient ambulatory EEG (CO-LTM) was evaluated. The study included patients referred to a community-based service for further diagnostic evaluation using a 16-channel ambulatory monitor. Referring physicians were surveyed to evaluate if the results of their patients' monitoring sessions were associated with a change in their clinical management. Surveys were sent to 45 physicians referring the first 149 patients monitored. 121 surveys (81%) were returned from 31 physicians, a 69% response rate. The monitoring results were associated with non-neurological referrals in 40% of cases, referral for in-patient monitoring in 14%, a change in medication in 23% of cases, and resulted in no change in only 19% of the cases. A follow-up sample of 25 patients confirmed reduced or event freedom in 21, 2 unchanged and 2 unknown. Five of the six patients had had their diagnosis confirmed following video EEG. In conclusion, CO-LTM provides clinically useful information.
The correlation between phospholamban and sarcoplasmic reticulum Ca(2+)-transporting ATPase levels and the magnitude of phospholamban-mediated stimulation of sarcoplasmic reticulum Ca2+ transport was examined in microsomes prepared from rabbit and canine cardiac, slow twitch and fast twitch skeletal muscle. Phospholamban was absent from microsomes prepared from fast twitch skeletal muscle but present at comparable levels in microsomes prepared from cardiac and slow twitch skeletal muscle. Levels of Ca(2+)-transporting ATPase were higher in microsomes prepared from slow twitch skeletal muscle than in microsomes prepared from cardiac muscle, however, and ratios of phospholamban to Ca(2+)-transporting ATPase were several fold greater in microsomes prepared from cardiac muscle than in microsomes prepared from slow twitch skeletal muscle. Stimulation of ATP-dependent Ca2+ transport following phosphorylation of phospholamban by cAMP-dependent protein kinase or incubation with anti-phospholamban monoclonal antibody was observed only in cardiac muscle microsomes. These observations indicate that phospholamban, while present in both cardiac and slow twitch skeletal muscle, may be involved in the hormonal regulation of sarcoplasmic reticulum Ca2+ transport only in the former, and that the lack of phospholamban-mediated stimulation of Ca2+ transport in slow twitch skeletal muscle sarcoplasmic reticulum may result from the lower ratio of phospholamban to Ca(2+)-transporting ATPase in this tissue.