Gamma oscillatory activity in vitro: a model system to assess pathophysiological mechanisms of comorbidity between autism and epilepsy.

Autism spectrum disorder (ASD) and temporal lobe epilepsy exhibit remarkable comorbidity, but for reasons not clearly understood. To reveal a common pathophysiological mechanism, we here describe and characterize an in vitro epileptiform activity in the rat hippocampus that exhibits common features with in vivo activity in rodent ASD models. We discovered the development of this activity in the CA1 region of horizontal slices after prolonged interictal-like epileptiform activity in the CA3 region that was provoked by incubation in high potassium artificial cerebrospinal fluid. The CA1 epileptiform bursts were insensitive to blockers of glutamatergic transmission, and were carried by synaptic as well as extrasynaptic, tonically activated gamma-aminobutyric acid type A (GABA(A)) receptors. The bursts bear resemblance to in vivo gamma-oscillatory activity found in rat ASD models with respect to their gamma frequency spectrum, their origin (in the CA1), and their sensitivity to blockers of cation-chloride pumps (NKCC1 and KCC2), as well as to oxytocin. Considering this bursting activity as an in vitro model for studying comorbidity between epilepsy and ASD may help to disentangle the intricate interactions that underlie the comorbidity between both diseases and suggests that extrasynaptic tonic GABAergic transmission could represent a potential target for ASD.

Oral triiodothyronine in the perioperative management of central hypothyroidism.

Oral triiodothyronine (T3) has never been described in literature as a major form of perioperative therapy. This series highlights the role of oral triiodothyronine in the perioperative management of patients with overt hypothyroidism for semi-urgent surgeries. We describe 12 patients with central hypothyroidism occurring secondary to pituitary tumours manifesting with severe neurological symptoms that required early surgical intervention. These patients were managed without any significant complications by administering perioperative oral triiodothyronine.

Solitary fibrous tumor of the lateral ventricle: CT appearances and pathologic correlation with follow-up.

Intracranial solitary fibrous tumors are rare, and intraventricular fibrous tumors are even more unusual. We report a case of solitary fibrous tumor in the region of trigone and body of the left lateral ventricle and discuss the clinical presentation, CT characteristics, and histopathologic features with 1-year follow-up. We speculate that the tumor arose from the perivascular connective tissue of the choroid plexus.

To assess the ability of MRI to predict consistency of pituitary macroadenomas.

We prospectively studied the ability of magnetic resonance imaging (MRI) to predict the consistency of pituitary adenomas. The hypothesis was that firm, fibrous tumours would appear homogeneously hypointense on T2-weighted images. Eighty patients who underwent surgery for pituitary macroadenomas were studied. MR images were evaluated preoperatively by the radiologist. The tumour consistency was reported by the surgeon as soft or firm. There were 68 soft tumours and 12 firm tumours. Of the firm tumours, four (33%) were homogeneously isointense, one (8%) homogeneously hyperintense and seven (59%) were heterogeneous in appearance in T2-weighted images. We conclude that the consistency of pituitary macroadenomas cannot be accurately predicted based on MRI signal intensities.

Suprabrow minicraniotomy for suprasellar tumours.

We present our experience with suprabow minicraniotomy in the excision of 18 suprasellar tumours between May 2001 and September 2003. There were 14 females and four males with ages ranging from 7 to 59 years. The tumours included one epidermoid cyst, 10 meningiomas, five craniopharyngiomas and two optico-chiasmatico-hypothalamic (OCHG) gliomas. The size of the one-piece craniotomy was about 2.5 cm. Both OCHGs were biopsied; one craniopharyngioma was totally excised, the remaining craniopharyngiomas and epidermoid cyst were subtotally excised. Four meningiomas were radically excised and six were subtotally removed. The patient with a craniopharyngioma that had a radical excision died of hypothalamic dysfunction. One patient developed a postoperative meningitis and subsequent hydrocephalus requiring a shunt. The other patients did well and the cosmetic result was excellent in all cases. This basal approach through a small craniotomy provided good surgical access to suprasellar tumours with minimal brain retraction.

Extensive vertebral haemangioma with cord compression in two patients: review of the literature.

Two cases of extensive vertebral haemangioma with progressive neurological deficits are described. Successful treatment was accomplished with palliative surgical decompression after preoperative embolization in one case and with postoperative radiotherapy in the other. Preoperative embolization, palliative surgical decompression and postoperative radiotherapy appear to provide satisfactory outcome in patients with extensive haemangiomas.

Superior sagittal sinus and torcula thrombosis in minor head injury.

A 27-year-old man suffered a relatively minor trauma. He developed signs of raised intracranial pressure three days after injury. Investigations revealed superior sagittal sinus and torcular thrombosis.

Intratumoral abscess: an unusual complication of ventriculoperitoneal shunt infection.

INTRODUCTION: Ventriculoperitoneal shunts were routinely used in the past in children with posterior fossa tumors and hydrocephalus. They can, however, cause a multitude of problems. CASE REPORT: This report highlights a previously unencountered phenomenon of a pyogenic abscess forming within a posterior fossa ependymoma as a result of shunt infection. The shunt was exteriorized and the child treated with antibiotics before surgery was done. Only a partial excision of the tumor was possible, as the inflammatory response caused by the abscess had obliterated tissue planes.

The 'capsule' of pituitary macroadenomas represents normal pituitary gland: a histopathological study.

The goal of trans-sphenoidal pituitary adenoma surgery is radical excision of the tumour with preservation of endocrine function. Our hypothesis was that, even in macroadenomas extending into the suprasellar cistern, the 'capsule' of the tumour is the compressed normal pituitary gland. The biopsy material from 126 patients with pituitary macroadenomas were retrospectively reviewed to look for the presence of normal adenohypophysis. Fourteen patients with macroadenomas operated trans-sphenoidally were studied prospectively, sampling tissue from the periphery of the tumour for histopathology. From the retrospective data, we found that normal adenohypophysis was more often found at histopathology in the extracapsular excisions, rather than in the intracapsular excisions. In the 14 patients studied prospectively, normal adenohypophysial tissue was found histologically at all sites sampled except in areas where the tumour was invasive. In conclusion, while an extracapsular excision would offer the best chance for a surgical cure, preserving parts of the capsule may preserve normal and possibly functioning gland.

Intraoperative ultrasound in determining the extent of resection of parenchymal brain tumours--a comparative study with computed tomography and histopathology.

BACKGROUND: Radical excision of parenchymal brain tumours is generally associated with a better long-term outcome; however, it is difficult to ascertain the extent of resection at surgery. We used intra-operative ultrasound [IOUS] to help detect residual tumour and define the tumour-brain interface. METHODS: Thirty-five patients with parenchymal brain lesions including 11 low-grade and 22 high-grade tumours and 2 inflammatory granulomata were included in the study. The IOUS was used to localize tumours not seen on the surface, define their margins and assess the extent of resection at the end of surgery. Multiple samples from the tumour-brain interface which were reported as tumour or normal tissue on IOUS were submitted to histopathology. The IOUS findings were compared with a postoperative contrast enhanced computed tomogram [CT] and with histopathology. RESULTS: All tumours irrespective of histology were hyperechoic on IOUS. IOUS was useful in localizing those tumours not seen on the surface of the brain. In 71.4% of cases IOUS was useful in defining their margins, however in the remaining cases the margins were ill-defined. The tumour margins were ill-defined in those treated previously by radiation. With regard to the extent of excision, after excluding the cases who were irradiated, it was found that in the 28 patients who had parenchymal neoplasms, there was concordance between the ultrasound findings and the postoperative CT scan in 23 cases. Of the 79 samples taken from the tumor-brain interface which were reported as tumour on ultrasound, 66 had histopathological evidence of tumour while 13 samples were negative for tumour. On the other hand, in the tissue sent from 17 sites where the IOUS showed no residual tumour, 2 were positive for tumour on histopathology while 15 were negative. INTERPRETATION: In conclusion, IOUS is a cheap and useful real-time tool for localizing tumours not seen on the brain surface, for defining their margins and for determining the extent of resection.

A minimally invasive approach to deep-seated brain lesions using balloon dilatation and ultrasound guidance.

Conventional dissection techniques require the excision of a channel from the cortex through the white matter with suction and bipolar cautery for the excision of deep-seated brain lesions. An alternative approach, using a previously described technique, in four cases is illustrated in this article. After craniotomy and dural opening, the index finger portion of a surgical glove was removed, tied over a brain cannula and gently passed towards the lesion under ultrasound guidance. Once the needle-tip was sonologically confirmed to be on the lesion, the balloon was inflated with about 3 to 5 ml of saline. This created a track through which the lesion could be excised under the microscope. The lesions were satisfactorily excised through the track created without removal of brain tissue. The accuracy of this minimally invasive technique can be enhanced when used in conjunction with intraoperative ultrasound guidance.

Transsphenoidal line of vision on MRI for pituitary tumor surgery.

This study was done to determine the usefulness of the sagittal magnetic resonance image (MRI) in predicting the ease of resectability of pituitary adenomas operated through the transsphenoidal route. Tumors were graded according to Hardy's method and a new system proposed by us. In this system the amount of tumor above the line of vision (V-line) as seen on the sagittal MRI was estimated and correlated with the extent of excision assessed on the postoperative computed tomogram (CT). There were 7 Hardy's grade A (8.8%), 32 grade B (41.3%), 31 grade C (37.5%), 6 grade D (8.8%) and 2 grade E tumors (3.8%) among the 78 tumors studied. It was seen that most of the tumor volume was below the V-line in Hardy's grade A and B tumors. In grade C tumors 5 were < 25% above, 14 were 25-50% above and 12 were 50-75% above the V-line. A radical excision was possible in 15 of l9 grade C tumors in which < 50% of the tumor was above the V-line. However, only 5 of 12 with Hardy's grade C were radically excised when >50% of the tumor was above the V-line. In conclusion, Hardy's grade C tumors are not a homogenous group radiologically and using the V-line on MRI helps in predicting the case of respectability in a single stage.

Hemorrhagic necrosis of pituitary adenomas.

A clinicopathological study of 41 cases of pituitary apoplexy in a series of 324 surgically treated pituitary adenomas is presented. In 23 patients, the predominant operative finding was hemorrhage with or without necrosis. However, there were 15 (37.7%) cases where pale, necrotic tissue with no evidence of hemorrhage was found at surgery. Pale, necrotic material was particularly found when there was a long interval between the acute clinical event and surgery. It is concluded that the pale, necrotic debris represents one stage in the resorption process of blood after hemorrhagic necrosis of pituitary adenomas. This entity needs to be kept in mind especially since the material closely resemble the pultaceous material seen in craniopharyngiomas and epidermoid cysts.

Syringomyelia in spontaneous intracranial hypotension. Case report.

The authors describe the presence of a syrinx in a patient with spontaneous intracranial hypotension. The likely pathophysiological basis of this hitherto unreported association is also presented. It is believed that chronic obstruction at the foramen magnum may be the most important factor for the development of syringes.

Similarities between civilian gunshot wounds to the head and nongunshot head injuries.

BACKGROUND: This investigation compared the cerebral pathophysiologic status of gunshot wounds to the head (GSWH) with that of severe head injury of other causes (non-GSWH). METHODS: Data were collected prospectively from 71 GSWH and 541 non-GSWH patients. The two groups had similar demographic characteristics and injury severities. Cerebral metabolic parameters for each patient were averaged for the entire period of monitoring. These per-patient averages were compared between GSWH and non-GSWH groups. RESULTS: Median intracranial pressure was 21.4 mm Hg in GSWH patients vs. 16.7 mm Hg in non-GSWH patients (p < 0.001). Mean arterial pressures were similar, but the higher intracranial pressure in GSWH patients produced a lower median cerebral perfusion pressure. Cerebral blood flow, cerebrovascular resistance, cerebral metabolic rate of oxygen, average jugular venous oxygen saturation, and number of jugular venous desaturations did not differ significantly between the groups. Three-month outcome was death in 43% of GSWH patients and 32% of non-GSWH patients, persistent vegetative state or severe disability in 33% and 32%, respectively, and moderate disability or good recovery in 24% and 36%, respectively. These outcomes were not significantly different (p = 0.11). CONCLUSION: GSWH patients suffer global cerebral metabolic disturbances that are at least as severe as those seen in non-GSWH patients with injuries of comparable severity. This selected population of GSWH patients may enjoy outcomes comparable to those of non-GSWH patients if they are treated by the same aggressive protocols.

Favorable outcome after radical excision of a 'Holocord' astrocytoma.

We report a favorable outcome following a staged radical excision of an intramedullary low-grade astrocytoma involving the entire spinal cord in a pediatric patient. Although the preoperative neurological status was poor, the eventual outcome was good. This highlights the importance of a good tumor-cord interface that permitted a radical excision of an extensive tumor. Since partial excision followed by radiotherapy usually results in disease progression in patients with low-grade astrocytomas, radical excision and follow-up is probably the treatment of choice.

Diagnostic and staged stereotactic aspiration of multiple bihemispheric pyogenic brain abscesses.

BACKGROUND: Empiric antibiotic therapy for multiple brain abscesses is not advised, as biopsy to rule out other causes and material for cultures can be obtained with minimal morbidity using computed tomography (CT)-guided stereotaxy. METHODS: We report a good outcome following treatment of this 60-year-old nonimmunocompromised patient with six pyogenic cerebral abscesses. CT-guided stereotactic aspiration of two abscesses were done on the first occasion and appropriate antibiotics were administered. Serial CT scans were done and the abscesses that recollected or enlarged were again aspirated. RESULTS: Group A beta hemolytic streptococci were grown from the pus. Two abscesses recollected and one enlarged during antibiotic therapy. These were aspirated on the second and third occasions, 1 week and 2 weeks after the first procedure. The abscess less than 3 cm resolved with antibiotics alone. Intravenous crystalline penicillin, chloroamphenicol, and metronidazole were given for 2 weeks followed by oral ampicillin and cotrimoxazole for 10 weeks. There was no morbidity related to the multiple procedures and the patient had a good outcome at the end of 16 weeks. CONCLUSIONS: CT-guided stereotactic aspiration of multiple brain abscesses is known to have a low morbidity and mortality. We highlight the additional option of multiple, staged aspirations for those abscesses not readily responding to antibiotic therapy.

Complications of transsphenoidal pituitary surgery.

Two hundred and sixty four transsphenoidal procedure for excision for pituitary adenomas were performed in the Christian Medical College Hospital at Vellore between 1983 and 1994. These were reviewed to evaluate the complications and their management. There were four operative deaths (1.5). Major morbidity included cerebrospinal fluid (CSF) rhinorrhoea, meningitis, diabetes insipidus, visual deterioration and Addisonian crisis. Intraopertive CSF leak had a high association with postoperative diabetes insipidus.