Fourth ventriculostomy for Chiari malformation.
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Biomedical subjects
Publications and source records attributed to N Tulipan.
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Grafts of neonatal striatal tissue were placed into the striata of adult rats. When challenged immediately with intrastriatal injections of either kainic or quinolinic acid, excitotoxic damage was prevented. Thirty days later these same graft recipients received another injection of excitotoxin. The intrastriatal grafts continued to mitigate toxin-induced damage. It is hypothesized that the grafted cells not only survive, but that they may continue to elaborate some substance or substances that prevent excitotoxin-induced injury for at least 30 days. Previous investigations indicated that grafts of neonatal striatal tissue can protect the recipient striatum from kainic acid toxicity. In the following study it is demonstrated that such grafts also protect the striatum from quinolinic acid, an endogenous excitotoxin which induces kainate-like neuronal degeneration and has been implicated in the pathogenesis of Huntington's disease. It is postulated that the salutary effect of striatal grafting may be sufficiently long lasting to mitigate a chronic toxic insult. Such grafting may therefore represent a therapy for Huntington's disease and other neurodegenerative disorders in which an endogenous or exogenous toxin has been implicated as the pathogenetic agent.
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There is now a wealth of experimental evidence to suggest that transplantation to the brain may ameliorate a variety of neurologic and endocrine disorders. Many unanswered questions remain. Chief among these questions are the duration of any salutary effects and the potential long-term risks to the host CNS. Answers to these questions will only come with carefully controlled long-term clinical studies. Given the high incidence and devastating nature of many of these diseases, such studies will have enormous scientific and social impact. Regardless of the outcome, there is the potential for a greater understanding of the pathologic mechanisms underlying neurodegenerative diseases and, thus, the possibility that definitive therapies will be found as a result.
It is reported that unilateral grafts of neonatal striatal tissue protect the recipient from the lethal aphagia and adipsia produced by bilateral intrastriatal injection of 10 nmol of kainic acid in rats. It is shown that neither adult striatum nor neonatal tissue from other sites have the same lifesaving effect and that the salutary effect of the graft is dependent upon graft survival. Grafts from a histoincompatible donor are apparently rejected, leading to the death of the recipient. Cyclosporine inhibits rejection thereby enabling recipient survival. It is postulated that the graft exerts a neurohumoral influence that protects the striatum from the toxic effect of kainate.
Pediatric head injury is a public health problem that exacts a high price from patients, their families and society alike. While much of the brain damage in head-injured patients occurs at the moment of impact, secondary injuries can be prevented by aggressive medical and surgical intervention. Modern imaging devices have simplified the task of diagnosing intracranial injuries. Recent advances in monitoring technology have made it easier to assess the effectiveness of medical therapy. These include intracranial pressure monitoring devices that are accurate and safe, and jugular bulb monitoring which provides a continuous, qualitative measure of cerebral blood flow. The cornerstones of treatment remain hyperventilation and osmotherapy. Despite maximal treatment, however, the mortality and morbidity associated with pediatric head injury remains high. Reduction of this mortality and morbidity will likely depend upon prevention rather than treatment.
OBJECTIVE: To determine the effect of gestational age at the time of intrauterine myelomeningocele repair on the duration of pregnancy and the gestational age at the time of delivery. METHODS: This study is a retrospective chart review of the maternal and neonatal medical records of all infants undergoing intrauterine myelomeningocele repair at Vanderbilt University Medical Center. Birth weight, gestational age at the time of surgery and gestational age at the time of delivery were recorded. Infants were divided into 2 groups depending on gestational age at the time of surgery, either > or = 25 weeks' gestation (group 1) or < 25 weeks (group 2). Results were expressed as medians and interquartile ranges. Statistical analysis was done using the unpaired (2-sample) t test; p values < or = 0.05 were considered significant. RESULTS: Ninety-five infants were studied. Fifty-one infants were repaired after 25 weeks' gestation (group 1) at a median gestational age of 26.3 weeks (range 25.6-27.6). Their median gestational age at delivery was 34.4 weeks (range 32.6-35.3). Forty-four infants were repaired before 25 weeks' gestation (group 2). Surgery was done at a median gestational age of 23.6 weeks (range 22.4-24.5). The median gestational age at delivery was 34 weeks (range 31.6-35.3; p = 0.88). CONCLUSION: Early intrauterine myelomeningocele repair before 25 week's gestation does not decrease the gestational age at delivery when compared with repair after 25 weeks.
OBJECTIVE: To determine whether short-term complications of prematurity are affected by intrauterine myelomeningocele repair. METHODS: Medical records of the first 100 infants undergoing intrauterine myelomeningocele repair (IUMR) at the Vanderbilt University Medical Center were reviewed. Infants born at <34 weeks' gestation were identified. Two controls were identified for each IUMR infant. Controls were matched for gestational age, sex, birth weight, antenatal steroids, and mode and month of delivery. Development of respiratory distress syndrome, intraventricular hemorrhage, and chronic lung disease and days on ventilator and length of hospital stay were recorded. The results are expressed as mean values and ranges. Comparison of data between groups was performed using the Mann-Whitney U test. Categorical data were compared using the chi-square test and Fisher's exact test. p </= 0.05 was considered statistically significant. RESULTS: One hundred infants underwent IUMR. Forty-four infants were born at <34 weeks of gestation. Complete data were available on 37 infants. Seventy-four matched controls were studied. Eleven infants from the IUMR group and 23 infants from the control group developed respiratory distress syndrome (29.7 vs. 31.1%; p = 0.8). Six infants from the IUMR group and 13 infants from the control group developed chronic lung disease (16.2 vs. 17.5%; p = 0.9). The length of stay was 28 (range 2-82) days for the IUMR group and 24 (range 1-99) days (p = 0.09) for the control group. There was also no significant difference between groups with regard to intraventricular hemorrhage and days on ventilators. CONCLUSION: There is no difference between short-term complications of prematurity following IUMR and those associated with prematurity resulting from other causes.