Effect of interstitial stereotactic radiosurgery on behavior and subjective handicap of epilepsy in patients with gelastic epilepsy

Patients with symptomatic epilepsy due to hypothalamic hamartomas often are compromised not only by pharmacoresistant epileptic seizures but also by behavioral disturbances and cognitive dysfunction. We report the effect of successful treatment with stereotactic interstitial radiosurgery by intrahypothalamic implantation of 125I seeds on behavior and subjective handicap. In all patients rendered seizure-free or suffering only from auras, improvement of behavior was reported by parents and colleagues or schoolteachers. Parents' ratings according to the Child Behavior Checklist showed improvements with respect to social problems and attention. Self-ratings of quality of life by adult patients showed improvements in activities, working situation, and self-perception. These improvements were not observed in patients in whom clinically manifest seizures and interictal EEG discharges persisted after radiosurgery.

Voluminoso hamartoma hipotalámico en un niño de 5 meses: Epilepsia y cirugía

The authors report the case of 5-month-old boy with a hypothalamic hamartoma and persistent gelastic seizures in spite of a wide combination of different antiepileptic drugs. It was decided to carry out only partial removal of the tumor for decompression and to decreasing the activity of the epileptogenic focus. Surgical therapy revealed as a valid option in the treatment of the uncontrollable gelastic seizures.

The treatment of patients with hypothalamic hamartomas, epilepsy and behavioural abnormalities: facts and hypotheses

The growing interest in the association between hypothalamic hamartomas (HH), epilepsy and behavioural abnormalities witnessed in recent years, has led to significant progress regarding the clinical presentations, pathophysiology and management of this entity. Patients with these lesions may occupy different points within a spectrum of severity of the epileptic and behavioural disorder, and may dynamically progress toward more malignant epilepsies with time. The role of the subcortical lesion in the generation of the gelastic seizures has been established, and encouraging results have been obtained with surgical resection, destruction or disconnection of the hamartoma. The present work highlights several aspects that should be taken into account for the selection of medical and surgical treatment for individual patients. We conclude with a reflection on what we still do not understand as regards in the genesis and surgical management of the neuropsychiatric disabilities related to this disorder.

Hypothalamic hamartoma in adults

Epilepsy in adult patients with hypothalamic hamartoma has not been well studied. It is uncommon but merits recognition. In this paper, 14 adult patients with hypothalamic hamartoma and epilepsy, of whom three developed epilepsy only in adult life, are presented. The later onset of epilepsy appears to be associated with a milder epilepsy syndrome, less severe learning difficulties and behaviour problems, and better occupational and social status. Gelastic seizures are less prominent in this age group. Of particular interest, one patient had prominent sleep disturbances characterized by a reduction in total slow wave and REM sleep without daytime sleepiness. The milder epilepsy and preserved cognitive and social functioning have implications for management. A number of patients were controlled by anticonvulsant medication, and were functioning satisfactorily. For such patients minimally invasive surgical procedures, or medical therapy should be considered.

Transcallosal resection of hypothalamic hamartomas in patients with intractable epilepsy

A variety of surgical treatments for intractable epilepsy with hypothalamic hamartoma (HH) are described, although most are derived from limited patient experience gathered from several centres. We describe the results of transcallosal resection of HH in 29 consecutive patients undergoing surgery at one centre. Twenty-nine patients aged 4-23 years (mean 10 years) underwent HH surgery with a minimum of 12 months follow-up. A comprehensive, presurgical epilepsy evaluation, supplemented with endocrine and ophthalmological assessments was performed in all cases. HH were resected via a transcallosal, interforniceal approach to the third ventricle, with the assistance of frameless stereotaxy, limiting the resection to the margins of the third ventricular walls and floor and minimising traction and diathermy. Complete or near-complete (>95%) resection of the HH was achieved in 18/29 patients, 75-95% resection was achieved in seven patients (four of whom had complete or near-complete disconnection of residual HH) and less than 50% resection was achieved in four. Postoperatively (follow-up 12-70 months, mean 30 months), 15 became seizure-free (nine off antiepileptic medication), seven had >90% reduction in seizure frequency, three had 55-80% reduction in seizure frequency, and four had less than 40% reduction in seizure frequency. Of 16 patients who had seizures in the early postoperative period, six became seizure. No patient or lesion characteristics were associated with postoperative seizure freedom, including features of symptomatic generalised epilepsy. Neurobehavioural improvement and resolution of EEG abnormalities were seen in the majority. Complications were transient hemiparesis in two, transient hypernatraemia in 17, short-term memory impairment in 14 (persistent in four), weight gain in ten (persistent in five), need for supplemental thyroxine in five, and lowered growth hormone (uncertain clinical significance) in six. Transcallosal resection of HH is an effective treatment for intractable epilepsy, with 76% patients in our seizures being seizure-free or having >90% seizure reduction. The operative risks include stroke, short-term memory disturbance, weight gain and minor endocrine disturbances. Based on published data, the transcallosal approach appears to be safer and more effective than other operative strategies.

Hypothalamic hamartoma with refractory epilepsy: surgical procedures and results in 18 patients

AIM

To study the surgical procedures and results on seizures, in 18 patients with refractory epilepsy due to hypothalamic hamartoma.

PATIENTS AND METHODS

Eighteen patients aged from 9 months to 32 years underwent surgery between 1997 and 2002. The mean age at seizure onset was 15.5 months. Seventeen patients had gelastic seizures, 14 had partial seizures, two had infantile spasms, 10 had tonic or atonic seizures and three had generalized seizures. The mean seizure frequency was 21 per day. Four patients had borderline intellectual disability and the others were mentally retarded. Five patients had precocious puberty, one had acromegaly and four suffered from obesity. Brain MRI, performed at least twice in each patient showed the hamartoma as a stable, homogeneous interpeduncular mass implanted either on the mammillary tubercle or on the wall of the third ventricle, with variable extension to the bottom. Ictal SPECT, performed in four patients, showed hyperperfusion within the hamartoma in two.

SURGICAL PROCEDURE

Twenty-six operations were performed in 18 patients. The first patient underwent a total removal of the hamartoma, whereas the following patients underwent a disconnection, either through open surgery (14 patients) or endoscopy (10 patients).

RESULTS

Regarding the seizure outcome with a mean follow up of three years four months (one year to 4.5 years), nine patients are seizure-free, one patient has only brief gelastic seizures and eight are dramatically improved. Surgery was uncomplicated in all but two patients: one had transitory hemiplegia and paresis of the third cranial nerve, the other presented with hemiplegia due to ischemia of the middle cerebral artery territory. The quality of life, behavior and school performance were greatly improved in most of the patients.

CONCLUSION

Our series illustrates the feasibility and relative safety of disconnecting surgery of hypothalamic hamartomas, with seizure relief in 50% and a dramatic improvement in the others. Endoscopic disconnection seems to be a very safe way to treat the intra-ventricular part of hamartomas.

Morphometry of the anterior third ventricle region as a guide for the subfrontal (translaminaterminalis) approach

The anterior third ventricle region acquires clinical significance in benign and malignant tumors and cyst formations, of which craniopharyngiomas and gliomas are the most common. The subfrontal approach is one of the most preferred approaches for removing these tumors. In this study, the microsurgical anatomy of 81 Turkish, adult cadaveric hemispheres was examined to provide morphometric data of the region. These measurements from the anterior third ventricle region serve as a guide for neurosurgeons during surgical approach for removing anterior third ventricle tumors.

Hypothalamic hamartoma and seizures: a treatable epileptic encephalopathy

Hypothalamic hamartomas may be associated with gelastic seizures, focal seizures, and a generalized epileptic encephalopathy, with severe seizures and cognitive and behavior decline. Despite earlier views to the contrary, good evidence now exists that all these clinical features are caused, directly or indirectly, by the hamartoma. Resection of these lesions was long regarded as too hazardous and unlikely to benefit seizure control. It is now clear that hypothalamic hamartomas can be effectively treated with a variety of surgical approaches with sustained seizure control and often seizure freedom. Qualitative observations suggest that behavior and cognition also improve with treatment, but quantitative validation is required. The specific approach should be tailored according to the surgical anatomy of the lesion and the experience of the surgeon. Choices include a transcallosal approach (good for intraventricular lesions), a pterional approach (useful for interpeduncular lesions), a transventricular endoscopic approach, or destruction of the lesion with radiofrequency probes or gamma knife radiosurgery. The previously dismal outlook for children with severe seizures associated with this lesion has now dramatically changed. These insights may have implications for other epileptic encephalopathies of childhood.

Neuroendocrine regulation of seasonal gonadotrophin and prolactin rhythms: lessons from the Soay ram model

Marked seasonality, responsiveness to photoperiod, diurnal behaviour, large body size, long lifespan and adaptability in captivity are characteristics that make the Soay ram a useful model for neuroendocrine research. Adult rams are routinely housed indoors under artificial lighting of alternating 16 week periods of long and short days to entrain the seasonal cycles in reproduction, growth and metabolism. The long-term cycles in individuals are monitored directly (measurements of testis diameter, androgen-dependent skin coloration, food intake, pelage moult, locomotor activity) and retrospectively (measurements of reproductive and metabolic hormone concentrations in peripheral blood). A wide spectrum of experimental procedures, including serial blood and cerebrospinal fluid (CSF) sampling with hormone or drug treatments, tissue biopsy, stereotaxic cerebral implantation and surgical lesions, not feasible in smaller species, are used to investigate the multiple interactive neuroendocrine systems regulating seasonality. The results from a recent experiment in which rams received a lesion of the caudal arcuate nucleus (caudal ARCX) or hypothalamo-pituitary disconnection (HPD) are presented to demonstrate the fidelity of long-term data derived from the Soay ram model. The results support the view that the melatonin signal that encodes photoperiod acts within the mediobasal hypothalamus to time the gonadotrophin/gonadal cycle, but acts directly within the pituitary gland to time the prolactin/pelage cycle.

A population-based study of the incidence and survival rates in patients with pilocytic astrocytoma

OBJECT

The incidence of pilocytic astrocytomas and the rate of patient survival were analyzed in a population-based study in the canton of Zürich, Switzerland.

METHODS

Between 1980 and 1994, 987 astrocytic and oligodendroglial tumors were diagnosed, of which 55 (5.5%) were pilocytic astrocytomas. The incidence rate, adjusted to the World Standard Population, was 4.8 per 1 million per year. The mean age at clinical diagnosis was 19.6 +/- 12.7 years, and the male/female ratio was 1.12. The most frequent tumor sites were the cerebellum (40%), followed by supratentorial locations (35%), the optic pathway and hypothalamus (11%), and the brainstem (9%). The mean follow-up period was 12 years. Observed survival rates were 100% at 5 years and 95.8% at 10 years after diagnosis (relative survival rate at 10 years: 96.8%). Seven patients (13%) received postoperative radiotherapy, but this did not significantly affect survival. In all patients the tumors were histologically classified as WHO Grade I, except in two patients who had anaplastic pilocytic astrocytoma (Grade III), one of whom died after 7 years, whereas the other was still alive after 10 years.

CONCLUSIONS

This population-based study shows that, because of the benign biological behavior of pilocytic astrocytomas and advances in microneurosurgery, the survival rates for patients with these tumors are excellent, regardless of postoperative radiotherapy.

Hypothalamic hamartomas: seven cases and review of the literature

Hypothalamic hamartomas constitute rare developmental lesions associated with gelastic epilepsy and/or precocious puberty (PP). We elected to review cases encountered at our center (7 patients) and the existing literature (277 patients) to obtain a better understanding of the clinical aspects, pathogenesis, and treatment of this entity. Evidence suggests that gelastic seizures are due to intrinsic epileptogenicity. The cause of the subsequent development of other seizure types, cognitive decline, and diffuse spike-and-wave pattern remains unresolved and is addressed. Anticonvulsants often fail to control seizures and different surgical options are available. Available evidence suggests that a resection through a subtemporal approach is best for lesions that are pedunculated or with a significant prepontine component, while a transcallosal approach is more appropriate for sessile lesions with an intraventricular component. Gamma knife surgery may be especially useful for small sessile lesions, failed partial resections, or patients not appropriate or refusing open surgery.

Oestrogen-induced vigorous mounting in female rats carrying hypothalamic knife cuts

In ovariectomized Wistar rats, 1- or 2-mm wide knife cuts were placed in a coronal plane from the surface of the cortex to the floor of the cranial cavity to interrupt posterior efferents of the ventromedial nucleus of the hypothalamus (VMN). Sham-operated females had the same knife lowered to a depth of 7 mm. Ovariectomized nonoperated females were also used. After recovery, all rats received a single injection of 2 microg oestradiol benzoate, and were tested 48 h later for male and female sexual behaviour and partner preference. When placed with highly receptive stimulus females, the rats with the 2-mm cut showed a significantly higher incidence of mounting with ejaculatory thrusts than any other groups. When placed with stud males, 1-mm cut, as well as sham-operated females, had increased lordosis quotients. Similarly, both 1-mm and 2-mm cuts and sham operation enhanced the incidence of ear wiggling. Despite the display of a transsexual behaviour (i.e. vigorous mounting), all females with the cut showed heterosexual partner preference. Thus, the cut in the present study removed the inhibitory neural effect on mounting, which presumably descends from the VMN. In the absence of this inhibition, minute amounts of oestrogen sufficed to induce vigorous mounting. Sham operation in the present study appeared to interfere with certain inhibitory neural circuitry for lordosis.

[Modern day psychosurgery: a new approach to neurosurgery in psychiatric disease]

AIMS

To obtain an up to date review of the different possible surgical approaches in the management of certain psychiatric disorders that are refractory to conservative treatment (pharmacotherapy, psychotherapy, electroconvulsive therapy).

METHOD

In order to conduct this research we reviewed the work published by centres with the most experience in this type of surgery, mainly in North America and Europe, since its beginnings in the 1930s, with the controversy concerning prefrontal leucotomy, until the appearance of modern stereotactic techniques. We analyse the anatomophysiological bases, their main clinical indications, the surgical techniques used and their results, as well as perspectives for the future of this neurosurgical treatment.

CONCLUSIONS

The most noteworthy progress in psychosurgery in recent years has been the combination of a more rigorous selection of patients and the higher degree of specificity with which treatment is performed on the brain structures involved in psychiatric disease. The most widely employed psychosurgical procedures at present are cingulotomy, anterior capsulotomy, subcaudate tractotomy, limbic leucotomy and postero medial hypothalamotomy, with favourable responses in about 35 70% of cases. The psychiatric diagnoses where the best results are to be found are obsessive compulsive disorder, chronic anxiety states and major depression. Current progress in neuroimaging techniques, increased neurophysiological knowledge and the revolutionary neuromodulation techniques, especially deep brain stimulation, offer an even more promising future for psychiatric neurosurgery.

Stereotactic radiosurgery for hypothalamic hamartomas

Hypothalamic hamartomas are nonneoplastic lesions often characterized by central precocious puberty and gelastic epilepsy. Due to the delicate location surgery is often unsuccessful and associated with considerable risks. In the presented series, Gamma Knife radiosurgery was applied. Four cases (aged between 5-13 years) who presented with medically intractable gelastic epilepsy and increasing secondary generalization, abnormal behaviour and precocious puberty (3 cases) are reported. Hypothalamic hamartomas sized 11-17 mm had been diagnosed by MR imaging. Radiosurgical treatment was performed in general anaesthesia with margin doses of 12-14 Gy to the 50-90% isodoses covering volumes of 600-2300 mm3. After follow-up periods of 12 to 68 months, a continuing decrease both in seizure frequency and intensity was noted (outcome according to Engel: II a (3 cases) and III a (1 case)). All patients are socially reintegrated. MR imaging did not reveal significant changes concerning the size of the lesions. Gamma Knife radiosurgery can be an effective and safe alternative treatment modality for HH capable of achieving good seizure control and improving behavioural disorders in selected cases.

Third ventriculostomy through the lamina terminalis for intracranial pressure monitoring after aneurysm surgery: technical note

OBJECTIVE

A new ventriculostomy technique through the lamina terminalis is described. This technique is applied mainly during aneurysm surgery at the acute stage.

METHOD

Thirteen patients were operated on intracranial aneurysms and, during the procedure, had the lamina terminalis fenestrated. A ventricular catheter was inserted into the third ventricule, left in place and connected to an external drainage system for further intracranial pressure (ICP) monitoring and/or cerebrospinal fluid (CSF) drainage.

RESULTS

ICP readings and CSF drainage were obtained in all cases. No complication was recorded.

CONCLUSION

Third ventriculostomy through the lamina terminalis is a simple and easy technique that can be used as an alternative to conventional ventriculostomy. This procedure can be indicated in cases where the ventricule is not reached by means of another technique, and when the decision to perform ventriculostomy is made at the end of aneurysm surgery.

Microsurgical fenestration of the lamina terminalis reduces the incidence of shunt-dependent hydrocephalus after aneurysmal subarachnoid hemorrhage

OBJECTIVE

Hydrocephalus requiring shunt placement is a common complication after aneurysmal subarachnoid hemorrhage (aSAH). Previous investigations suggest that fenestration of the lamina terminalis during microsurgery for aSAH may be associated with a reduced rate of shunt-dependent hydrocephalus. We report a retrospective analysis correlating fenestration of the lamina terminalis with decreased shunt-dependent hydrocephalus after aSAH.

METHODS

During the past decade, 582 patients were admitted to our institution with aSAH. We compared the rate of shunting in patients operated on by a neurosurgeon ("index neurosurgeon") who routinely fenestrated the lamina terminalis (>98% of his patients) with that in patients managed by 14 other neurosurgeons who rarely fenestrated the lamina terminalis (<5% of their patients) and by 6 interventional neuroradiologists. The total cohort was subdivided into two groups on the basis of surgical approach and microsurgical access to the lamina terminalis. Group A included frontosphenotemporal craniotomies, an approach in which the lamina terminalis is accessible, and Group B included other approaches in which the lamina terminalis is not accessible. Shunting rates of the index neurosurgeon and those of the other practitioners were compared within Groups A and B. Shunting rates were compared by logistic regression and multivariable analysis. This study design isolates the effect of fenestrating the lamina terminalis on the incidence of shunt-dependent hydrocephalus.

RESULTS

In Group A, the index neurosurgeon had a significantly lower rate of shunting, 2.3%, versus 12.6% for other practitioners (P = 0.011; odds ratio, 0.15). In Group B, in which the approach did not allow microsurgical fenestration of the lamina terminalis, there was no difference (P = 0.789) in the rate of shunting between the index neurosurgeon (10.0%) and other practitioners (13.2%).

CONCLUSION

Fenestration of the lamina terminalis appears to be associated with a decreased incidence of shunt-dependent hydrocephalus of more than 80% after aSAH. This straightforward microsurgical maneuver should be performed whenever possible during aneurysm surgery.

Psychosurgery

The author describes the three commonly practiced surgical methods in the treatment of mental illness, i.e., cingulotomy, anterior capsulotomy, and posteromedial hypothalamotomy.

Primary hypothalamic-third ventricle lymphoma. Case report and review of the literature

Primary central nervous system lymphomas (PCNSL) are infrequent tumors and their presentation as a solitary hypothalamic-third ventricle mass can be considered exceptional. We report the case of a 57-year-old woman with progressive visual deterioration, diabetes insipidus and mental confusion. She had a diffuse and homogeneous tumoral lesion involving the third ventricle and the adjacent hypothalamic area with marked enhancement after contrast administration on both, competed tomography scan and magnetic resonance images. It was approached and partially resected by the translamina terminalis route. Histological diagnosis proved to be a diffuse non-Hodgkin lymphoma and the patient subsequently was treated with adjuvant radiotherapy and chemotherapy. Followup examination showed visual acuity recover but persistent confessional state. Eight similar well described cases reported in the literature are reviewed with a description of the major diffenciating features of this neurological entity. Treatment of PCNSL remains a challenge, and the topographical location within the hypothalamic-third ventricle area is even more complex.

Microsurgical treatment for hypothalamic hamartoma in children with precocious puberty

BACKGROUND

We review the surgical treatment of hypothalamic hamartoma causing precocious puberty.

METHODS

Six children (three girls and three boys) with precocious puberty secondary to hypothalamic hamartoma were recruited for our study. The mean age of the patients was 30 months old (range 13 months to 5 years), and the mean age of the onset of puberty was 7.3 months. All patients were treated by microsurgery.

RESULTS

All patients had higher then normal stature, body weight, bone growth, and serum levels of sexual hormones. The boys presented with mature external genitalia, pubic hair, frequent erection, and acne, while the girls presented with growth of breasts and menarche. Magnetic resonance image (MRI) revealed an isointense mass below the tuber cinereum extending into the supersellar and interpeduncular cistern, ranging from 4 to 12 mm in diameter, consistent with pedunculate hamartoma. The hamartoma was removed completely via a right pterional approach. The symptoms and signs of precocious puberty resolved completely, and sexual hormone levels decreased to the pre-pubertal range in all six patients without any postoperative complications.

CONCLUSION

We report a series of six children with hypothalamic hamartoma-induced precocious puberty who underwent microsurgical treatment. All of them recovered completely to their age-appropriate state. Microsurgery is a good choice of treatment for pedunculate hypothalamic hamartoma.

[Gamma knife radiosurgery for the treatment of severe epilepsy]

The Gamma Knife radiosurgery is a neurosurgical approach having now demonstrated well its efficiency, its low morbidity and its comfort in the treatment of numerous neurosurgical disorders. These advantages of this type of intervention make it a method of great interest in functional neurosurgery and quite particularly in surgery of epilepsy. French experience is a pionner one in this domain. If for several years the positive evolution of the epilepsy associated to brain lesions had been noticed after the Gamma Knife radiosurgical treatment, the use of this approach in surgery of the epilepsy is systematically estimated since 1993. Data are today available concerning the surgical treatment of the epilepsies originating in temporomesiale area without occupying process, epilepsies associated to hypothalamic hamartomas and epilepsies associated to cavernous angiomas or to low grade gliomas. The quality of the epileptological result obtained in these various indications associated to a very reduced morbidity lets suppose that the Gamma Knife radiosurgery could indeed have tomorrow a place within the sample group of surgical approaches dedicated to the treatment of severe epilepsies. However, a larger number of treated patients and a more prolonged follow-up remains necessary to estimate in a more definitive way this approach.

Microsurgical anatomic features of the lamina terminalis

OBJECTIVE

The lamina terminalis (LT) is a structure of considerable interest for microneurosurgery, and precise knowledge regarding its normal anatomic features and the variations thereof is required. The purpose of this study, which was based on microanatomic dissection of human cadaveric specimens, was to review the microsurgical anatomic features of the LT and its neurovascular relationships. The surgical implications of the morphometric data are discussed.

METHODS

The region of the LT was examined in 10 human cadaveric heads, obtained from 8 fresh adult cadavers and 2 formalin-fixed adult cadavers, and in 10 formalin-fixed, isolated, adult brains. An operating microscope was used for all dissections and measurements.

RESULTS

Assuming the LT to be a triangular structure, we performed measurements of the distance between the midportion of the upper edge of the chiasm and the lower edge of the anterior commissure (height), which averaged 8.25 mm. The distance between the medial edges of the optic tracts (base) averaged 12.81 mm. The area averaged 52.84 mm(2). A minimal amount of retraction was needed to fully expose the LT, and generally there was no need to mobilize the anterior cerebral artery-anterior communicating artery complex. Perforating branches to the hypothalamus and optic apparatus are laterally located and do not interfere with LT incision and/or fenestration.

CONCLUSION

The LT constitutes a clearly identifiable microsurgical target. The allowable extent of LT opening is sufficient to provide wide access into and free cerebrospinal fluid flow from the third ventricle. Fenestration of the LT is a safe procedure, provided that the relevant anatomic landmarks are identified and respected.

Sympathoadrenal counterregulation in patients with hypothalamic craniopharyngioma

In humans, the role of hypothalamic centers for activation of counterregulatory release of catecholamines and glucagon during hypoglycemia is unclear. To address this question, we investigated the counterregulatory response to acute insulin-induced hypoglycemia of glucagon, epinephrine, and norepinephrine in eight patients who had undergone transcranial surgery for a craniopharyngioma extending to the hypothalamic region. We compared the patients' responses with those of four patients suffering from hypopituitarism and of six healthy subjects. After the i.v. injection of 0.1 U of human insulin per kg of body weight in the patients or 0.15 U in healthy subjects, the plasma glucose concentrations decreased to similar minimum levels within 30 min in all three groups. All subjects recovered spontaneously from hypoglycemia within 2 h. In five of eight craniopharyngioma patients, only a small counterregulatory rise in plasma epinephrine (< or =2-fold) and norepinephrine could be observed (P < 0.05 for epinephrine and P = 0.22 for norepinephrine vs. healthy controls). During hypoglycemia, virtually no adrenergic symptoms (tremor, heart pounding, and anxiety) were reported by these five patients, and changes in the heart rate were diminished. In three craniopharyngioma patients, the counterregulatory increase in catecholamines was unimpaired, adrenergic symptoms were reported and a rise in heart rate was observed during hypoglycemia. In all craniopharyngioma patients, the counterregulatory glucagon response to hypoglycemia was preserved and orthostasis increased both catecholamines and the heart rate similar to in the patients with hypopituitarism as well as in the healthy controls. Our results demonstrate selective impairment of counterregulatory sympathoadrenal activation in patients who had undergone surgery for a craniopharyngioma extending to the hypothalamic region. This strongly suggests the involvement of hypothalamic centers in hypoglycemia-induced activation of the sympathoadrenal axis in humans. It remains unclear as to whether hypoglycemia-induced glucagon secretion is also controlled by the hypothalamus. However, a common hypothalamic center controlling both counterregulatory catecholamine and glucagon release is unlikely, and sympathoadrenal activation is not required for hypoglycemia-induced glucagon secretion in humans.

Preservation of the hypothalamic structures in the total resection of craniopharyngioma

OBJECTIVE

To explore an effective method of surgical management of craniopharyngioma.

SUBJECTS AND METHODS

Fifty patients with craniopharyngioma had total and subtotal tumor ectomy. There were 29 males and 21 females, ranging in age from 15 to 56 years (mean 34.1 years). MR imaging showed that the tumors were located in the superior sellar region in 24 cases, in superior sella region and extended into the third ventricular floor in 19 cases, into parasella in 3 cases and down to intrasella in 4 cases. Complete cystic tumors were found in 5 cases, while the partial cystic tumor in 24 cases and complete solid tumors in 21 cases. Pterional approach was used in 48 patients and subfrontal approach in 2 patients. Great attention was paid to the preservation of the perforating arteries from the carotid, posterior and anterior communicating and anterior choroidal arteries to the hypothalamic structures. The clinical outcome was evaluated according to the GOS scale.

RESULTS

Of the 50 patients surgically treated, 47 patients obtained total ectomy of the tumor and 3 patients with the secondary surgery had subtotal ectomy of the tumor. The pituitary stalk was preserved in 29 (58%) patients, severed in 14 patients and unidentified in 7 patients. Forty-six patients regained a normal life; one patient needed assist in life. Of the 3 deaths, one patient died of diabetes insipidus, one of inhalation asphyxia, and another one of water and sodium disorders.

CONCLUSION

Avoidance of the injury to the neural structures in the third ventricular floor and preservation of the perforating arteries to hypothalamus are the key to achieve good surgical results in treating craniopharyngioma.

Regulation of ovarian hyperluteinization

Adult female rats with neonatally damaged posterior hypothalamus, made by a transversal cut, were investigated. Plasma levels of prolactin (PRL), gonadotropic hormones (GTH) and female gonadal steroids (GS) were determined by radioimmunoassay. The animals were sacrificed, at the ages of 4 and 6 months and their hypothalamus, pituitary gland, ovary and uterus were examined using light microscopy. The results can be summarized as follows: body mass of animals, with damaged posterior hypothalamus, was significantly reduced. Masses of luteinized ovaries were increased and uterine tissues decreased. Serum levels of PRL were significantly increased and luteinizing hormone (LH) decreased. Ultrastructural changes in the corpora lutea (CL), previously described, showed clear signs of their reduced capacities to produce GS, both estradiol (Oe) and progesterone (Pg) per total ovarian mass. However, prostaglandin 2 alfa (PGF2alpha) known as a luteolytic factor, was also diminished in the evidently retarded endometrium. As a result of decreased plasma values of LH, Pg and PGF2 alpha, luteolysis of CL in hyperluteinized ovaries did not occur, and their new generations were accumulated during subsequent cycles. The character of interruption and recovery of aminergic and peptidergic neurons, involved in regulation of hypothalamic-pituitary gonadal axis and feed-back effects of steroid hormones, require further studies.

Hypothalamic hamartoma: the role of surgery in a series of eight patients

Hypothalamic hamartoma are rare lesions. We report a new series of eight patients treated for precocious puberty (six cases) or gelastic seizures (two cases). Surgical resection was total in four cases (three pediculated and one sessile). Precocious puberty was controlled by surgical treatment in all cases. Gelastic seizures were controlled by medical treatment, but the patients did not become seizure free. We observed no mortality and no endocrinological or visual morbidity. The fact that a vascular "rete mirabilis" was observed on the surface of the lesion in our surgical material is an argument favoring a vascular mechanism in precocious puberty. Coagulation of this vascular structure can help control precocious puberty. Our series confirms that the hypothalamic hamartoma can be surgically treated when patients fail to respond to medical treatment, when the length of the treatment cannot be tolerated by the chidren and their families, and when there are uncontrolled gelastic seizures

Hormonal regulation of hippocampal spine synapse density involves subcortical mediation

It is well established that estrogen has positive effects on the density of pyramidal cell spines in the hippocampal CA1 subfield. This study explored whether afferent connections of the hippocampus that come from estrogen-sensitive subcortical structures, including the septal complex, median raphe and supramammillary area, play a role in this estrogen-induced hippocampal synaptic plasticity. These particular subcortical structures have major influences on hippocampal activity, including theta rhythm and long-term potentiation. The latter also promotes the formation of new synapses. All of the rats were ovariectomized; the fimbria/fornix, which contains the majority of subcortical efferents to the hippocampus, was transected unilaterally in each, and half of the animals received estrogen replacement. Using unbiased electron microscopic stereological methods, the CA1 pyramidal cell spine synapse density was calculated. In the estrogen-treated rats, contralateral to the fimbria/fornix transection, the spine density of CA1 pyramidal cells increased dramatically, compared to the spine density values of both the ipsilateral and contralateral hippocampi of non-estrogen-treated animals and to that of the ipsilateral hippocampus of the estrogen replaced rats. These observations indicate that fimbria/fornix transection itself does not considerably influence CA1 area pyramidal cell spine density and, most importantly, that the estrogenic effect on hippocampal morphology, in addition to directly affecting the hippocampus, involves subcortical mediation.

Lesions of the dorsomedial hypothalamic nucleus do not influence the daily profile of pineal metabolism in rats

The present study attempted to characterize the effects of electrolytic lesions of the hypothalamic dorsomedial nucleus on the daily profile of pineal metabolism as well as on the inhibition of pineal melatonin synthesis induced by acute light exposure during the night. Adult male Wistar rats (n = 107, 12:12 h light-dark cycle) were left intact (n = 47) or lesioned (n = 60). Lesioned rats and their respective controls were killed at six time points distributed throughout the light-dark cycle. At ZT (zeitgeber time) 18 the animals were killed either in the dark or after 15 min of light stimulation. Pineal glands were assayed using high-performance liquid chromatography with electrochemical detection (HPLC-ED). There was no difference in the amounts of pineal indoles between lesioned and control rats under any of the experimental situations tested. These results suggest that in rats, the hypothalamic dorsomedial nucleus does not participate in either the neural control of daily pineal metabolism or the nocturnal light-induced inhibition of the pineal metabolism.

Surgical treatment of hypothalamic hamartoma and refractory seizures: a case report and review of the literature

Refractory gelastic seizures are often associated with hypothalamic hamartoma (HH). Presurgical evaluation in such children often points to a distinct cortical region as the source of the seizures. A case of a child with HH and refractory seizures is presented. Video-EEG monitoring revealed a well-defined epileptic focus in the left frontal region. In accordance with the current understanding of the nature of hamartoma-related seizures, the hamartoma was resected. Follow-up evaluations revealed a marked improvement in seizure frequency and global functioning.

Hypothalamic hamartoma associated with an arachnoid cyst

A hypothalamic hamartoma associated with an arachnoid cyst in an 8-year-old boy is reported herein. He presented with precocious puberty, and neuroimaging studies demonstrated a solid mass in the prepontine cistern and a huge arachnoid cyst in the left cranial fossa. The mass appeared isointense to the surrounding cerebral cortex on T1-weighted magnetic resonance images, hyperintense on T2-weighted images, and was not enhanced after administration of Gd-DTPA. The patient underwent a left frontotemporal craniotomy and a cyst-peritoneal shunt was inserted. Histological features of the cyst wall and the mass were characteristic of an arachnoid cyst and hamartoma, respectively. While a hypothalamic hamartoma associated with an arachnoid cyst is rare, such a case may help clarify the geneses of both anomalous lesions.

TTF-1, a homeodomain gene required for diencephalic morphogenesis, is postnatally expressed in the neuroendocrine brain in a developmentally regulated and cell-specific fashion

TTF-1 is a member of the Nkx family of homeodomain genes required for morphogenesis of the hypothalamus. Whether TTF-1, or other Nkx genes, contributes to regulating differentiated hypothalamic functions is not known. We now report that postnatal hypothalamic TTF-1 expression is developmentally regulated and associated with the neuroendocrine process of female sexual development. Lesions of the hypothalamus that cause sexual precocity transiently activate neuronal TTF-1 expression near the lesion site. In intact animals, hypothalamic TTF-1 mRNA content also increases transiently, preceding the initiation of puberty. Postnatal expression of the TTF-1 gene was limited to subsets of hypothalamic neurons, including LHRH neurons, which control sexual maturation, and preproenkephalinergic neurons of the lateroventromedial nucleus of the basal hypothalamus, which restrain sexual maturation and facilitate reproductive behavior. TTF-1 mRNA was also detected in astrocytes of the median eminence and ependymal/subependymal cells of the third ventricle, where it colocalized with erbB-2, a receptor involved in facilitating sexual development. TTF-1 binds to and transactivates the erbB-2 and LHRH promoters, but represses transcription of the preproenkephalin gene. The singular increase in hypothalamic TTF-1 gene expression that precedes the initiation of puberty, its highly specific pattern of cellular expression, and its transcriptional actions on genes directly involved in neuroendocrine reproductive regulation suggest that TTF-1 may represent one of the controlling factors that set in motion early events underlying the central activation of mammalian puberty.

Renal nerve inhibition by central NaCl and ANG II is abolished by lesions of the lamina terminalis

The lamina terminalis is situated in the anterior wall of the third ventricle and plays a major role in fluid and electrolyte homeostasis and cardiovascular regulation. The present study examined whether the effects of intracerebroventricular infusion of hypertonic saline and ANG II on renal sympathetic nerve activity (RSNA) were mediated by the lamina terminalis. In control, conscious sheep (n = 5), intracerebroventricular infusions of 0.6 M NaCl (1 ml/h for 20 min) and ANG II (10 nmol/h for 30 min) increased mean arterial pressure (MAP) by 6 +/- 1 (P < 0.001) and 14 +/- 3 mmHg (P < 0.001) and inhibited RSNA by 80 +/- 6 (P < 0.001) and 89 +/- 7% (P < 0.001), respectively. Both treatments reduced plasma renin concentration (PRC). Intracerebroventricular infusion of artificial cerebrospinal fluid (1 ml/h for 30 min) had no effect. In conscious sheep with lesions of the lamina terminalis (n = 6), all of the responses to intracerebroventricular hypertonic saline and ANG II were abolished. In conclusion, the effects of intracerebroventricular hypertonic saline and ANG II on RSNA, PRC, and MAP depend on the integrity of the lamina terminalis, indicating that this site plays an essential role in coordinating the homeostatic responses to changes in brain Na(+) concentration.

Cardiovascular responses in anticipation of changes in posture and locomotion

Measurements were made in 29 adult baboons that were housed in social groups, allowing the occurrence of the full range of species-specific behavioral interactions. The cardiovascular variables measured included blood pressure, heart rate, renal blood flow, lower limb blood flow, and occasionally mesenteric blood flow. The data were telemetered from backpacks worn by the animals and were recorded in analogue form on a polygraph, digitally on a computer and were also recorded on the audio channels of videotape being made of the behavior and social interactions of the baboons. The video and the computer recordings were synchronized by a timing system that made it possible to relate the cardiovascular responses to the behavioral responses. A numerically based behavioral code was developed that allowed the categorization of the totality of the behavior, including postural and locomotor changes. Comparisons between baseline cardiovascular values and those occurring 1 s before the initiation of a movement or posture change gave no evidence of anticipatory cardiovascular responses unless the movement was associated with behavior that included emotional content. Hypothalamic perifornical lesions reduced or eliminated these anticipatory changes.

[Hypothalamic hamartomas: control of seizures after partial removal in one case]

OBJECTIVE

To describe a patient with intractable seizures and hypothalamic hamartoma that was only partially resected with complete control of seizures and improvement in behavior after surgery.

CLINICAL CASE

He had gelastic seizures from the first months of life associated with hypothalamic hamartoma. We used magnetic resonance spectroscopy to localize and measure the lesion in the temporal lobes and in the hamartoma. The relative intensity of N-acetylaspartate to creatine (NAA/Cr) and NAA/choline (Ch) were not significantly different from normal control subjects for either temporal lobes, whereas the ratio NAA/Ch was decreased and the ratio NAA/Cr was highly increased in the hamartoma. Despite only partial resection of the hamartoma, seizures have been completely controlled and the patient has recovered normal social and work activity and is ending a normal life, that follow three years after surgery.

CONCLUSIONS

These findings suggest that gelastic seizures associated with hypothalamic hamartoma are generated within the hamartoma itself, and that it is possible to control epilepsy and to improve intellectual and social problems with only partial resection of the mass.

Differentiating ability of the pars intermedia in hypothalectomized frog tadpoles

It is generally accepted that hypothalectomy of frog tadpoles at the open neurula stage results in failure of the pars intermedia to develop. A pale body color is assumed to be evidence that the hypothalamus was completely removed. The present study, however, shows that hypothalectomized Rana japonica can develop into either albino, as already reported, or darkly pigmented tadpoles. In order to determine the extent to which the intermediate lobe can develop in these hypothalectomized tadpoles, their adenohypophyses were examined immunohistochemically by using anti-alphaMSH (melanocyte-stimulating hormone). In all the dark-colored larvae a pars intermedia had formed, though its size was very small. In the pale-colored tadpoles, on the other hand, the pars intermedia frequently failed to differentiate, but it was observed in 4 of 13 hypothalectomized larvae. In view of other investigators' data showing the complete absence of ACTH (adrenocorticotropin) cells in hypothalectomized tadpoles, hypophyses were also stained with anti-ACTH. Immunoreactive ACTH cells were detected in hypothalectomized tadpoles irrespective of the body pigmentation, although their incidence was lower than in normal controls. These data indicate that contact between the infundibulum and adenohypophysis is not absolutely essential for differentiation of MSH and ACTH cells in the frog.

[Anti-algic surgical techniques]

OBJECTIVE

To review all the neurosurgical techniques currently used for the relief of pain.

DEVELOPMENT

The techniques described range from the classical operations causing lesions, such as neurotomy, rhizotomy, cordotomy, mesencephalotomy, thalamotomy, hypothalamotomy, cingulectomy, leukotomy and hypophysectomy, to the most modern, sophisticated techniques such as spinal and cerebral neurostimulation with administration of spinal morphine using continuous perfusion pumps. The indications, results and most usual complications of these techniques are described together with the techniques themselves.

CONCLUSION

It may be said that with this arsenal, modern medicine can control or alleviate over 90% of drug-resistant pain.

Growth hormone, insulin-like growth factor-1, and the insulin-like growth factor binding proteins in rats maintaining reduced body protein following lesions of the lateral hypothalamus

Rats with lesions of the lateral hypothalamus (LH) maintain a reduced body protein mass that they effectively defend when challenged by under- or over-nutrition. The two studies reported here evaluate the potential contributions of growth hormone (GH), insulin-like growth factor-1 (IGF-1), and the insulin-like growth factor-binding (IGFBP) to this persistent maintenance of a reduced body protein mass by LH rats. At 18 weeks postlesion, it was found that the serum levels of GH, IGF-1, total IGFBP, and IGFBP-3 of LH rats maintaining reduced body protein were not different from those of age-matched controls. However, closer to the time of surgery, at which time the lesion-induced body protein adjustments are known to occur, altered hormone and binding protein levels were observed. Specifically, at 3 weeks after lesioning, the IGF-binding proteins of LH rats were significantly elevated, whereas their GH levels were lower than those of controls. Because the GH, IGF-1, and IGF-binding proteins of LH rats were comparable to those of controls at 18 weeks after lesioning, none apparently underlie the chronically reduced body protein mass that LH rats display. Closer to the time of lesioning, however, altered GH and IGF binding protein levels may contribute to the postlesion adjustments by which the body protein mass of LH rats is lowered to its reduced level.

Stereotactic radiofrequency ablation for the treatment of gelastic seizures associated with hypothalamic hamartoma. Case report

The author presents the case of a patient with gelastic seizures associated with a hypothalamic hamartoma, in whom partial resection of the hamartoma followed by temporal lobectomy and orbitofrontal corticectomy failed to reduce the seizures. Subsequent stereotactic radiofrequency ablation of the hamartoma resulted in progressive improvement in the seizure disorder during a 28-month follow-up period. There is support in the literature for the concept that gelastic seizures originate directly from the hamartoma; however, direct surgical approaches to these lesions pose significant risks. It is proposed that the technique of radiofrequency ablation provides a minimally invasive, low-risk approach for the treatment of hypothalamic hamartomas.

The regulation of prolactin receptor messenger ribonucleic acid levels in the sheep liver before birth: relative roles of the fetal hypothalamus, cortisol, and the external photoperiod

We have investigated the separate actions of hypothalamo-pituitary disconnection (HPD), with or without cortisol administration, and changes in the external photoperiod on the regulation of the levels of messenger RNA (mRNA) encoding long (PRLR1) and short (PRLR2) forms of PRL receptor in the liver of the fetal lamb. In pregnant Merino ewes (n = 20), the hypothalamus and pituitary were surgically disconnected in 13 fetuses (HPD group), and fetal vascular catheters were implanted in the HPD group and in an additional 7 fetuses (intact + saline group) between 104-120 days gestation (d). Fetal sheep in the HPD group were infused with either cortisol (3.5 mg/4.8 ml saline/24 h; HPD + F; n = 5) or saline for 5 days between 134-141 d, and saline was also infused in the intact group within the same gestational age range. A second group of pregnant ewes (n = 12) was kept in a 12-h light, 12-h dark cycle from 70 d until implantation of fetal vascular catheters between 106-120 d, after which ewes were allocated to either a long photoperiod (16 h of light, 8 h of darkness; LL group; n = 6) or a short photoperiod (8 h of light, 16 h of darkness; SL group; n = 6) regimen. Circulating cortisol concentrations were higher (P < 0.05) in the intact fetal sheep (18.7 +/- 3.8 nmol/liter) than in the HPD + saline group (1.5 +/- 0.6 nmol/liter), and were further increased (P < 0.05) in the HPD + cortisol group (97.4 +/- 23.7 nmol/liter). Fetal PRL concentrations were lower (P < 0.05) in the HPD + saline (10.6 +/- 4.3 ng/ml) and HPD + cortisol (5.6 +/- 2 ng/ml) groups compared with those in the intact group (38.9 +/- 6.8 ng/ml). The levels of hepatic PRLR mRNA were higher (P < 0.05) in the intact (PRLR1, 27.4 +/- 6.1; PRLR2, 17.7 +/- 2.5) and HPD + cortisol (PRLR1, 23.4 +/- 0.4; PRLR2, 15.3 +/- 3.0) groups than in the HPD + saline group (PRLR1, 10.6 +/- 1.8; PRLR2, 8.9 +/- 1.8) at 140/141 d. The mean plasma PRL concentration in the LL group (70 +/- 9 ng/ml) was higher (P < 0.05) than that in the SL group (34 +/- 15 ng/ml), whereas the levels of hepatic PRLR1 mRNA (LL group, 4.6 +/- 0.9; SL group, 4.3 +/- 0.8) and PRLR2 mRNA (LL group, 3.4 +/- 0.4; SL group, 3.0 +/- 0.5) at 140-141 d were not different. These data indicate that cortisol acts directly or indirectly to maintain hepatic PRLR mRNA levels in the sheep fetus during late pregnancy. In contrast, changes in the external photoperiod and circulating PRL concentrations in the sheep fetus do not directly alter PRLR expression in the fetal liver. These studies provide further insight into the role that the PRL axis may play in the transduction of signals about the external environment to the fetus as it prepares for the transition to extrauterine life.

Adrenal responsiveness and the timing of parturition in hypothalamo-pituitary disconnected ovine foetuses with and without constant adrenocorticotrophin infusion

Ovine parturition results from an increase in foetal cortisol secretion in late gestation which is dependent on an intact hypothalamo-pituitary connection. The cortisol surge and parturition fails in hypothalamo-pituitary disconnected (HPD) foetuses but, paradoxically, immunoreactive (ir)-ACTH concentrations and secretory dynamics appear normal. This study compares the occurrence and timing of labour, basal ir-ACTH and cortisol concentrations and adrenal responsiveness in HPD foetuses (HPD/ACTH) receiving constant ACTH(1-24) infusion (43 ng/h/kg) from surgery (114+/-1 days gestational age (GA)) with those of saline-infused HPD or intact foetuses (HPD/SAL and INT/SAL). HPD/ACTH foetuses initiated labour at 147+/-2 days GA, which was not significantly different from INT/SAL foetuses (149+/-1 day GA). HPD/SAL foetuses were killed electively at 146+/-3 days GA with no signs of labour. Foetal ir-ACTH concentrations in all groups were indistinguishable, but only HPD/ACTH and INT/SAL foetuses had a significant cortisol surge. Adrenal responsiveness to ACTH(1-24)(1 microg/kg) was greater in HPD/ACTH foetuses than in HPD/SAL or INT/SAL foetuses at all GAs studied. Adrenal responsiveness in HPD/SAL foetuses exceeded that in INT/SAL foetuses at 120 and 130 days GA but did not change with GA. In summary, the basal cortisol and parturition defect in HPD foetuses was reversed by low-dose ACTH(1-24) infusion. Basal cortisol concentrations were unrelated to adrenal responsiveness. HPD/SAL foetuses had hyper-responsive adrenals compared to those of INT/SAL foetuses until 130 days GA, suggesting that the foetal hypothalamus exerts a negative influence on adrenal cortisol responses before 130 days GA, after which time stimulatory influences predominate.

The posterior basal diencephalon of rats enhances expression of an activated state

STUDY OBJECTIVES

Various ablation studies have implicated the posterior basal diencephalon in the promotion of wakefulness. Although many studies have examined the role of this structure in promotion of cortical arousal, few investigations have attempted to examine its importance in regulation of motor activation (behavioral arousal). In the current study, recordings of freely moving decerebrate rats with and without a posterior basal diencephalon were performed. These studies allowed determination of the behavioral states expressed by the preparations and whether removal of the posterior basal diencephalon completely eliminated expression of both activated state with and activated state without limb movements.

DESIGN

Muscle activity was recorded from limb and neck muscles. Eye movements and heart rate were also monitored. The percentage of time spent in various behavioral states and the proportion of limb movements expressed in each of these states were determined.

MEASUREMENTS AND RESULTS

Rats with an intact posterior basal diencephalon cycled between all behavioral states. However, they spent most of the recording time in an activated state. In contrast, removal of the posterior basal diencephalon produced rats that spent most of the recording period in a quiescent state. Limb movements were expressed mainly by animals with an intact posterior basal diencephalon, and only when these animals were in the activated state.

CONCLUSIONS

The results of this study suggest that the posterior basal diencephalon is required for expression of an activated state and specifically provide evidence for a descending projection from this region required for expression of this state and associated motor activation.

[Surgical treatment of GnRH secretory hypothalamic hamartomas causing precocious puberty]

Hypothalamic hamartomas (HHs) are benign lesions often associated with central precocious puberty. Resection of HHs has been recommended as a treatment option for selected cases, however recent reports stressed the role of effective medical management with a long-acting GnRH agonist. This paper describes incomplete response to the initial GnRH therapy and results of total resection of HHs. Five children two boys and three girls with physical signs of puberty at a mean age of 20.2 months (range 5-36 months) have been treated at our institution. All children had a pedunculated mass below the tuber cinereum. Two children were initially treated with GnRH agonist and had received follow-up care for 11 and 12 months respectively. These patients had incomplete regression of endocrinological disturbances to prepubertal level. Both patients were subsequently operated on. All five children underwent total surgical removal of HHs. The hamartomas were excised through pterional approach. Postoperatively two children showed transient third nerve palsy and one diabetes incipidus. There was no permanent disability due to surgical intervention. The clinical and biochemical symptoms and signs of precocious puberty completely regressed postoperatively including two cases treated initially with GnRH analog. The children have been followed for 1 to 6 years and no recurrence of puberty was observed. Surgical excision of pedunculated HHs is still a valuable option in the treatment of precocious puberty in small children. This alternative should be considered if the initial GnRH therapy failed to suppress++ puberty and reduce bone age advancement.

Developmental studies for identification of the inhibitory center of melanotropes in the toad, Bufo japonicus

Two series of experiments were performed to identify the inhibitory center of the melanotropes in the intermediate lobe of hypophysis of the toad, Bufo japonicus. First, developmental changes in the distribution of dopaminergic neurons were examined from hatching stage to postmetamorphosis using an antiserum against dopamine synthase (tyrosine hydroxylase, TH). In the postmetamorphic toads, TH-positive cell bodies were localized in three clusters. One was the preoptic recess organ (PRO) in the prechiasmatic area, the other two were the paraventricular organ (PVO) and infundibular nucleus (IN) in the postchiasmatic area. Each of them exhibited different ontogenetic changes. During larval development, TH-positive cell bodies were first detected in the PVO and IN at a premetamorphic stage. The number of immunoreactive cells increased rapidly in both loci as metamorphosis proceeded, although the two nuclei showed different growth profiles. By contrast, in the PRO, a very small number of immunoreactive cells were observed before the onset of the prometamorphic period. Although the number of immunoreactive neurons increased as metamorphosis progressed, early neurons were confined to the caudal area of the PRO (cPRO), the rostral area of the PRO (rPRO) being devoid of TH-positive cells. Immunoreactive TH neurons appeared in the rPRO for the first time at the end of metamorphic climax. This timing coincided well with the development of TH-positive nerve endings in the pars intermedia (PI) and median eminence. In the second series of experiments, the embryonic primordium of the PRO was surgically extirpated from open neurulae to examine the effects of PRO-ectomy. In 75% of the operated animals, background adaptation was not observed, their dermal melanophores remained permanently dispersed even on the white background. Dopaminergic neurons in the rPRO and the immunoreactive nerve endings in the PI and median eminence were scarcely observed in these animals. It was concluded that the present data strongly support the hypothesis that rPRO is the center of white-background adaptation.

Hypothalamic hamartoma: report of a case with unusual histologic features

A rare case of hypothalamic hamartoma with unusual radiologic and histopathological features is described, possibly the first of its type in English literature. A 1.5-year-old female child presented with precocious puberty. MR scan of the brain revealed a pedunculated hypothalamic mass, most of which was isointense with normal brain on T1- and T2-weighted images. However, a sizeable component of the lesion was hyperintense on T1-weighted images, suggestive of adipose tissue. Microscopically, the lesion was a hamartoma composed of an admixture of neuroectodermal elements, namely glial cells, neurons, and nerve bundles along with mesenchymal elements in the form of fibroadipose tissue.

[Epidermoid cyst of the third ventricle. Report of a case]

We report a case of epidermal (or epidermoid) cyst, in a 36-year-old man which developed in the third ventricle. Clinical manifestations were headaches and memory disturbances. On CT scan the tumor occupied the entire third ventricle but was mainly developed on the left side. On CT reconstructed images, the floor of the third ventricle was clearly visible. Using a trans-ventricular approach, the tumor, closely related to the left part of hypothalamus, was totally removed. Later on, because of persistent hydrocephalus, a ventricular shunt was inserted. An aseptic meningitis occurred and resolved spontaneously. The patient exhibited a postoperative transitory Korsakoff's syndrome. Postoperative endocrine investigations showed hypopituitarism. Some intra-ventricular epidermal cysts have been reported, especially involving the fourth ventricle. Their development into the third ventricle is unusual, and in early reports their precise origin appears doubtful. Although they have no characteristic radiological features, the location of epidermal cysts is clearly defined by the CT scan and especially MRI. It would be possible to totally remove epidermal cysts of the third ventricle, avoiding the risk of recurrence.

Time course of VMN lesion effects on lordosis and ultrasound production in hamsters

Lesions of the ventromedial hypothalamus (VMN) depress lordosis but increase ultrasonic vocalization in female hamsters. These changes are consistent with the behavioral incompatibility of lordosis and ultrasound production and suggest that the VMN coordinates short-term changes in these behaviors. In keeping with past results, unilateral lesions disrupted lordosis responses to contralateral flank stimulation. The change appeared within 15 min after the lesion and was much more rapid than the corresponding effect in rats. For hamsters, these findings support other evidence suggesting VMN mediation of somatosensory, not just hormonal, influences on lordosis. In a companion study, ultrasound rates became depressed within 15 min of bilateral lesion of the VMN, suggesting a role for the VMN in the short-term control of ultrasound production. Calling at later time intervals was facilitated by the lesions. The direction and time course of the lesion effects on lordosis and ultrasound production suggest that the VMN cannot easily account for the behavioral incompatibility of these 2 responses.

Melatonin receptors in the brain and pituitary gland of hypothalamo-pituitary disconnected Soay rams

In Soay rams in which the pituitary gland has been surgically separated from the hypothalamus, blood prolactin concentrations vary in response to changes in photoperiod and the administration of melatonin, as in intact animals, providing evidence that melatonin acts within the pituitary gland to control prolactin secretion. In this study the presence of potentially functional melatonin receptors in the pars tuberalis and zona tuberalis (PT/ZT) of hypothalamo-pituitary disconnected (HPD) Soay rams is confirmed using both in vitro autoradiography with the ligand 2-(125I)-iodomelatonin and in situ hybridization for the melatonin receptor. There was no effect of the HPD operation on the pattern and quantity of 2-(125I)iodomelatonin binding in the brain demonstrating that this binding is independent of hypothalamic regulation. The possibility that melatonin may control prolactin secretion directly via specific receptors on lactotrophs was investigated using dual in situ hybridization with a (35S) labelled probe for the ovine melatonin receptor (Mel 1a(b)) and a Digoxigenin labelled probe for ovine prolactin. Melatonin receptor gene expression was observed in the PT/ZT in both intact and HPD rams, however, there was no colocalization with prolactin gene expression; only in the ZT was there a close association between cells expressing the melatonin receptor and lactotrophs. The results provide strong support for the view that melatonin acts via the PT/ZT to mediate the effects of photoperiod on the seasonal cycle in prolactin secretion.