Upper level of the spina bifida defect: how good are we?

OBJECTIVE

To assess the accuracy of obstetric sonography in determining the upper level of myelomeningocele lesions.

METHODS

This was a retrospective study of 171 consecutive cases of spina bifida repaired in utero. The upper level of the lesion as determined by obstetric sonography was assigned by community physicians prior to referral in the second trimester and by the authors at Vanderbilt University Medical Center during preoperative evaluation. One hundred and eleven cases had levels established by plane-film X-ray or magnetic resonance imaging after delivery and this was regarded as the gold standard.

RESULTS

Of the 171 community examinations, only 29% identified a specific upper level of the lesion; our corresponding examinations specified the lesion level in all cases. Of the 111 cases that had upper levels of the lesion established by post-delivery imaging, corresponding levels were available for comparison from 35 of the community examinations and from 111 of the examinations performed at Vanderbilt. All three assigned levels were available for comparison in 35 cases. In 26% of cases, community-assigned levels agreed exactly with post-delivery levels, while 66% agreed within one level and 80% agreed within two levels. In 38% of cases, levels assigned at Vanderbilt agreed exactly with post-delivery levels, while 78% agreed within one level and 96% agreed within two levels. Upper levels of the lesion assigned at Vanderbilt were significantly more accurate overall compared with those assigned by community physicians (signed rank test [paired comparison], P = 0.048). However, comparison of lesion levels assigned at Vanderbilt in the first 50 vs. the last 61 cases revealed a significant learning effect (Fisher's exact test, P = 0.03). When comparison of lesion levels assigned by community physicians was restricted to the first 50 cases at Vanderbilt, accuracy was similar (n = 13; t-test, P = 0.16; rank sum test, 0.31).

CONCLUSIONS

Community physicians were successful in assigning the upper level of the spina bifida lesion only 29% of the time. When successful, the accuracy of these determinations was similar to that of the authors at Vanderbilt. A significant learning effect was demonstrated by improved accuracy over time at Vanderbilt. A concerted continuing medical education effort is indicated to improve the imaging skills of physicians in the accurate diagnosis of the severity of spina bifida in fetuses.

Intrauterine Myelomeningocele Repair: Effect on Short-Term Complications of Prematurity

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.

Gestational age at intrauterine myelomeningocele repair does not influence the risk of prematurity

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.

The urodynamic profile of myelodysplasia in childhood with spinal closure during gestation

PURPOSE

Spinal dysraphism is the most common cause of neurogenic bladder dysfunction in newborns. Urodynamic findings in these patients include uninhibited bladder contractions, bladder areflexia, decreased compliance and detrusor-sphincter dyssynergia. Early urodynamic studies are recommended for spina bifida to help identify bladder characteristics that may cause a risk of upper tract deterioration. We recently evaluated a new early type of intervention involving closure of the neural tube defect during gestation in 25 patients at our institution. We hypothesize that this procedure results in decreased exposure of the spinal cord to amniotic fluid, which may improve neurological function. To date we have evaluated 16 of the 25 patients with video urodynamics. We compared the results to those in the literature on patients with myelomeningocele and without prenatal intervention.

MATERIALS AND METHODS

We performed urodynamic testing in 16 patients with a mean age of 6.5 months, including cystometrography, fluoroscopic evaluation of filling and voiding, pelvic floor electromyography and post-void residual urine measurement. In addition, we retrospectively reviewed renal ultrasound, voiding cystourethrography, catheterization need, number of urinary tract infections and medication in these cases.

RESULTS

Uninhibited detrusor contractions and an areflexic bladder were identified in 6% and 43% of patients, respectively, while 19% had decreased compliance and 75% had leak point pressure greater than 40 cm. water. Mean bladder capacity was 40 cc and 31% of patients had much lower capacity than expected for age. Previous renal ultrasound and voiding cystourethrography showed evidence of upper tract dilatation and reflux in 2 cases, respectively. Intermittent catheterization and anticholinergic therapy were required by 1 patient each and 1 had a significant urinary tract infection.

CONCLUSIONS

Urodynamic findings in this population are comparable to those previously reported in the literature in patients with spina bifida without prenatal closure of the spinal defect. The lower incidence of urinary tract infection and reflux in our study probably represents more aggressive early urological management rather than neurological improvement. These urodynamic studies were performed early in life and future evaluation may ultimately reveal improved bladder function compared with that in others with myelodysplasia. However, at this time we recommend that patients who undergo spinal cord defect closure during gestation be evaluated and treated in the same manner as those with myelomeningocele but without fetal intervention.

Fetal MRI in the evaluation of intrauterine myelomeningocele

BACKGROUND

Accurate fetal imaging is essential to the practice of maternal-fetal medicine. While ultrasonography has been the traditional mainstay of fetal imaging, its ability to resolve critical features of central nervous system (CNS) anatomy remains limited. As interest in intrauterine therapy for myelomeningocele has increased, so has the need for more accurate, noninvasive imaging of the CNS. Fetal magnetic resonance imaging (MRI) promises to fill the gap left by ultrasound.

METHODS

Thirty-seven MRI scans of fetuses previously diagnosed with myelomeningocele were reviewed by 2 neuroradiologists. The ability of fetal MRI to resolve the commonest CNS stigmata of spina bifida, and the incidence and extent of interobserver error, was assessed. In 4 cases, postnatal MRIs were also available. These were compared to the corresponding fetal studies.

RESULTS

The imaging quality with the technique used in this study was excellent, even without the use of maternal or fetal sedation. There were no complications, and the imaging times were minimal. Interobserver error was minimal with respect to the evaluation of ventricular dilatation and hindbrain herniation, but moderate in the description and location of the spinal lesion. As had previously been documented with ultrasonography, a reduction was seen in hindbrain herniation when comparing pre- and postnatal MRIs.

CONCLUSION

It is concluded that fetal MRI is an effective, noninvasive means of assessing fetal CNS anatomy. Its ability to resolve posterior fossa anatomy is superior to ultrasonography while, with respect to the evaluation of hydrocephalus and the level and nature of the spinal lesion, it may be equivalent to inferior. Inclusion of the fetal MRI into the standard diagnostic armamentarium will probably await the next major advance in speed and resolution. It is conceivable that, with further advances, MRI might supplant ultrasonography as the diagnostic tool of choice for evaluation of fetal anomalies including myelomeningocele.

Use of bipedicular advancement flaps for intrauterine closure of myeloschisis

Several groups have begun to explore the feasibility and utility of intrauterine closure of myelomeningocele. A subset of these fetuses have defects which fall into the category of myeloschisis, and therefore have inadequate skin to enable primary closure. After considerable discussion, it was decided to utilize bipedicular flaps to close these lesions. The procedure is described, and representative examples are shown. To date, 13 of 56 fetuses have required this approach for closure in utero. While this technique generally provides adequate coverage of the dural sac, the cosmetic results have been less than optimal.

Fetal surgery for myelomeningocele and the incidence of shunt-dependent hydrocephalus

CONTEXT

Intrauterine closure of exposed spinal cord tissue prevents secondary neurologic injury in animals with a surgically created spinal defect; however, whether in utero repair of myelomeningocele improves neurologic outcome in infants with spina bifida is not known.

OBJECTIVE

To determine whether intrauterine repair of myelomeningocele improves patient outcomes compared with standard care.

DESIGN

Single-institution, nonrandomized observational study conducted between January 1990 and February 1999.

SETTING

Tertiary care medical center.

PARTICIPANTS

A sample of 29 study patients with isolated fetal myelomeningocele referred for intrauterine repair that was performed between 24 and 30 gestational weeks and 23 controls matched to cases for diagnosis, level of lesion, practice parameters, and calendar time. All infants were followed up for a minimum of 6 months after delivery.

MAIN OUTCOME MEASURES

Requirement for ventriculoperitoneal shunt placement, obstetrical complications, gestational age at delivery, and birth weight for study vs control subjects.

RESULTS

The requirement for ventriculoperitoneal shunt placement for decompression of hydrocephalus was significantly decreased among study infants (59% vs 91%; P = .01). The median age at shunt placement was also older among study infants (50 vs 5 days; P = .006). This may be explained by the reduced incidence of hindbrain herniation among study infants (38% vs 95%; P<.001). Following hysterotomy, study patients had an increased risk of oligohydramnios (48% vs 4%; P = .001) and admission to the hospital for preterm uterine contractions (50% vs 9%; P = .002). The estimated gestational age at delivery was earlier for study patients (33.2 vs 37.0 weeks; P<.001), and the birth weight of study neonates was less (2171 vs 3075 g; P<.001).

CONCLUSIONS

Our study suggests that intrauterine repair of myelomeningocele decreases the incidence of hindbrain herniation and shunt-dependent hydrocephalus in infants with spina bifida, but increases the incidence of premature delivery.

The Tulipan-Bruner trocar for uterine entry during fetal surgery

OBJECTIVE

Our goal was to compare the use of a specially designed trocar for initial uterine entry with standard entry by electrocautery in creation of a hysterotomy for fetal surgery.

STUDY DESIGN

Ten consecutive patients undergoing hysterotomy for intrauterine repair of myelomeningocele were randomized to initial uterine entry with electrocautery or with the Tulipan-Bruner trocar. Timing of initial uterine entry with electrocautery began with incision into the uterine serosa and ended with incision of the chorioamnionic membranes. Timing of initial uterine entry with the Tulipan-Bruner trocar began with placement of stay sutures and ended with removal of the central introducer from the peel-away sheath. Blood loss was estimated by the primary surgeon. All of the participating surgeons judged the convenience and ease of each technique. The times required for initial uterine entry were compared with an unpaired t test. Statistical significance was set at P <.05.

RESULTS

The time required for initial uterine entry with electrocautery was 231 +/- 63 (mean +/- SD) seconds compared with 146 +/- 51 seconds with the trocar (P <.05). The total blood loss for all 10 cases was <50 mL, but the presence of blood in the wound was judged much more inconvenient when electrocautery was used. Finally, electrocautery required 2 surgical assistants in every case, whereas the trocar was readily placed with only a single assistant.

CONCLUSION

The Tulipan-Bruner trocar provides quicker, less traumatic uterine entry during creation of a hysterotomy, as compared with electrocautery.

Effect of intrauterine myelomeningocele repair on central nervous system structure and function

BACKGROUND

It has been postulated that intrauterine myelomeningocele repair might improve neurologic outcome in patients with myelomeningocele. A total of 59 such procedures have been performed at Vanderbilt University. Preliminary results suggested that the degree of hindbrain herniation is reduced by intrauterine repair. In an attempt to further quantify the possible benefits of this surgery, a subset of these patients was brought back to Vanderbilt for study.

METHODS

A group of 26 patients who had undergone intrauterine myelomeningocele repair underwent an extensive evaluation which included manual muscle testing, MR imaging and precise determination of the anatomic level of their lesions as well as multiple other tests. The results of this analysis were compared to those in 2 groups of historical controls.

RESULTS

In this group of patients intrauterine myelomeningocele repair substantially reduced the incidence of moderate to severe hindbrain herniation (4 vs. 50%). The incidence of shunt-dependent hydrocephalus was more modestly reduced (58 vs. 92%). The average level of leg function closely matched the average anatomic level of the lesion in both the fetal surgery and control groups.

CONCLUSION

The most dramatic effect of intrauterine repair appears to be on hindbrain herniation. A less dramatic, but significant, reduction in shunt-dependent hydrocephalus is also seen. Prospective patients should be cautioned not to expect improvement in leg function as the result of this surgery. The potential benefits of surgery must be carefully weighed against the potential risks of prematurity.

Intrauterine myelomeningocele repair reverses preexisting hindbrain herniation

BACKGROUND

It has been reported that intrauterine myelomeningocele repair reduces the amount of hindbrain herniation normally seen in association with the Chiari type II malformation. It is not yet known, however, whether hindbrain herniation is prevented, or whether preexisting herniation is reversed. The following study was designed to elucidate this issue.

METHODS

A series of 9 patients underwent intraoperative ultrasound examinations immediately prior to intrauterine myelomeningocele repair. These same patients were then evaluated postnatally using ultrasound and/or MRI. The degree of hindbrain herniation before and after repair was compared using a grading system devised by the authors.

RESULTS

Eight patients had clear evidence of moderate to severe hindbrain herniation on intraoperative scans while one was mild. In contrast, on postnatal studies 5 of 9 patients had no evidence of hindbrain herniation, while the other 4 had only mild herniation.

CONCLUSION

Intra-uterine myelomeningocele repair appears to reverse preexisting hindbrain herniation. It is postulated that continuous flow of cerebrospinal fluid through the neural placode is the force responsible for inducing migration of the cerebellum and brain stem downward through the foramen magnum. By interrupting that flow during gestation, intrauterine myelomeningocele repair enables the cerebellum and brain stem to resume a normal, or nearly normal, configuration.

Reduced hindbrain herniation after intrauterine myelomeningocele repair: A report of four cases

BACKGROUND

It has been theorized that fetal myelomeningocele repair may reduce ongoing intrauterine injury and perhaps allow healing and regeneration of dysplastic neural tissue. We report on the postnatal imaging studies of the first 4 patients to have undergone intrauterine myelomeningocele repair at our institution.

METHODS

Each of the 4 patients underwent postnatal sonographic and MRI. In addition, the postnatal ultrasounds of these 4 were compared to a group of retrospective controls.

RESULTS

MRI scans of the 4 experimental subjects revealed no evidence of hindbrain herniation while other stigmata of the Chiari-II malformation persisted. In comparison to the retrospective controls this absence of herniation was distinctly unusual.

CONCLUSION

Intrauterine myelomeningocele repair may reduce the degree of hindbrain herniation normally seen in patients with myelomeningocele. This raises the possibility that intrauterine repair may decrease the morbidity associated with the Chiari type-II malformation including brainstem dysfunction, hydrocephalus and syringomyelia.

Stereotactic ventriculoperitoneal shunt for idiopathic intracranial hypertension: technical note

OBJECTIVE

Lumboperitoneal shunting is the bastion of neurosurgical management for idiopathic intracranial hypertension (IIH). However, recent studies document a high failure rate for this procedure. The present study was designed to explore the feasibility of placing ventriculoperitoneal shunts under stereotactic control into patients with IIH as an alternative to lumboperitoneal shunting.

METHODS

Seven patients with IIH for whom medical management had failed underwent stereotactic implantation of ventriculoperitoneal shunts.

RESULTS

Shunt placement was successful and uncomplicated in each case. Five of seven patients experienced complete resolution of papilledema. The remaining two patients showed resolving papilledema. Six of seven patients experienced resolution of headache. The remaining patient continued to have headaches despite a radionuclide study demonstrating normal shunt function.

CONCLUSION

Our results suggest that stereotactic ventriculoperitoneal shunting may be a reasonable alternative to lumboperitoneal shunting in those patients with IIH who require surgical intervention.

Pediatric head injury

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.

Myelomeningocele repair in utero: a report of three cases

BACKGROUND

Evidence accumulating over the last 10 years suggests that the exposed spinal cord tissue in a myelomeningocele sustains a secondary injury as the result of prolonged exposure to the intrauterine environment. These data suggest that early closure of the myelomeningocele sac might prevent such injury and in turn improve the neurologic outcome in the affected infant.

METHODS

Three patients with fetuses carrying the ultrasonic diagnosis of myelomeningocele elected to enter a study of the feasibility of repairing myelomeningocele in utero. At approximately 28 weeks of gestation each patient underwent laparotomy and hysterotomy, thus exposing the myelomeningocele defect. The defect was closed in a routine surgical fashion, and the hysterotomy was then closed.

RESULTS

The 3 patients recovered from surgery without incident. Early premature contractions subsided, and they were discharged by the 5th postoperative day. At between 33 and 36 weeks of gestation, each infant was delivered via cesarean section. The observed neurologic deficits were within the range expected from the anatomic level of the defects. Two of the infants have not required ventriculoperitoneal shunting.

CONCLUSIONS

This limited series of patients suggests that myelomeningocele can be repaired in utero with minimal morbidity to either the mother or her fetus. A larger study will be needed to substantiate this low morbidity and to determine the extent of any neurologic benefit of early surgery.

Quantitative analysis of the toxicity of human amniotic fluid to cultured rat spinal cord

It has been proposed that the myelodysplastic components of a myelomeningocele are secondarily damaged as the result of exposure to amniotic fluid, the so-called 'two-hit' hypothesis. The critical time at which this secondary insult might occur has not been clearly defined. The present study addresses this issue by quantitatively assessing the toxic effects of human amniotic fluid of various gestational ages upon organotypic cultures of rat spinal cord. Using an assay for lactate dehydrogenase efflux to evaluate toxicity in such spinal cord cultures, we found that the amniotic fluid became toxic at approximately 34 weeks' gestation. This toxic effect of amniotic fluid appears to emerge rather suddenly. Accordingly, it seems reasonable to suggest that prevention of exposure of vulnerable spinal cord tissue to this toxicity by surgical closure of a myelomeningocele defect prior to the emergence of toxicity in amniotic fluid may prevent injury to vulnerable myelodysplastic spinal cord tissue.

Neoplastic meningitis as the presentation of occult primitive neuroectodermal tumors

Seven children and young adults initially presented with subacute meningitis and/or increased intracranial pressure. The diagnosis of neoplastic meningitis secondary to a primitive neuroectodermal neoplasm was delayed by the absence of an obvious primary tumor. The neuroradiologic appearance was that of a basimeningeal infiltrative process, complicated by communicating hydrocephalus or "pseudotumor cerebri." Myelography was important in the diagnosis of disseminated meningeal malignancy in four cases. Cerebrospinal fluid cytologic diagnosis was insensitive but ultimately confirmed in five cases. All seven patients experienced progressive disease despite neuraxis radiotherapy and intensive chemotherapy; six have died. Systemic dissemination to bone and/or peritoneum occurred in three patients while on therapy. In two, a primary parenchymal brain or spinal cord tumor could not be identified at postmortem examination. The presentation of a primitive neuroectodermal tumor as subacute meningitis without an evident primary tumor heralds an aggressive and refractory neoplasm.

Alterations in prealbumin concentration after adrenal autotransplantation for Parkinson's disease

The cerebrospinal fluid of eight patients with Parkinson's disease who underwent adrenal medullary autotransplantation was analyzed using SDS-polyacrylamide gel electrophoresis. A protein, subsequently identified as prealbumin, was noted to change in concentration over the intraoperative to 18-month postoperative time course. The qualitative changes observed on visual inspection were confirmed and quantified using laser densitometry. The concentration of prealbumin increased by an average of 90% when the intraoperative and 12-month samples were compared. This increase persisted at 18 months. The ratio of prealbumin to albumin also increased from intraoperative to 12 months by an average of 56%. This suggests that the increases in PA are the result of choroid plexus activation rather than a nonspecific breakdown of the blood-brain barrier. Given the association of prealbumin with other nervous system diseases, as well as its known ability to bind multiple substances, these findings may have important implications. Alterations in prealbumin may be responsible for the improvement seen in some patients who receive adrenal medullary autotransplants. Alternatively, prealbumin may be implicated in the pathophysiology of Parkinson's disease.

Osteoblastic meningioma of the fourth ventricle

Meningiomas of the fourth ventricle are rare neoplasms. Only meningothelial and fibroblastic subtypes, purportedly arising from the tela choroidea, have been described. In this report we describe clinical, neuroradiological and pathological findings in a 52-year-old man with mild hydrocephalus produced by a large, calcified, osteoblastic meningioma of the fourth ventricle.

Striatal grafts provide sustained protection from kainic and quinolinic acid-induced damage

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.

Brain transplants. A new approach to the therapy of neurodegenerative disease

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.

Neonatal striatal grafts prevent lethal syndrome produced by bilateral intrastriatal injection of kainic acid

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.