Preferential reduction of synaptic efficacy in the dentate gyrus of hippocampal slices from aged rats during reduced glucose availability.

Glutamatergic synaptic activity entails a high energetic cost. During aging, a variety of neural metabolic changes have been reported that could compromise the capacity of neural circuits to maintain synaptic transmission during periods of reduced extracellular glucose. Indeed, a preferential compromise in evoked synaptic activity has been observed in hippocampal CA1 with age during exposure to low-glucose solutions. Whether this aging-related compromise in synaptic activity is regionally specific is unclear, however. Data suggest that the dentate gyrus (DG) preferentially exhibits hypometabolism with age and this region plays a critical role in spatial pattern separation, which is compromised with age. Therefore, we assessed whether synaptic activity is also preferentially affected in the DG with age. In vitro extracellular field potential recordings were used to monitor orthodromic and antidromic evoked activity in the DG granule cell layer in hippocampal slices from adult (8-12 months) and aged (22-27 months) rats in aCSF containing 10mM glucose, followed by a reduced glucose aCSF containing 1mM glucose. In 10mM glucose-aCSF, orthodromic- and antidromic-evoked field potential activity was comparable between age groups. However, orthodromic-evoked population spike amplitude and field excitatory post-synaptic potential (EPSP) slope were preferentially decreased in slices from aged rats during exposure to 1mM glucose-aCSF. Antidromic population spike amplitude was not differentially affected in slices from aged versus adult rats, however. These data suggest that synaptic efficacy is preferentially compromised with age under reduced glucose availability and, combined with a decreased capacity of the periphery to provide glucose to the central nervous system (CNS) during metabolically challenging conditions, could contribute to aging-related hippocampal dysfunction and cognitive decline.

Retrieval of kidney tissue for light microscopy from frozen tissue processed for immunofluorescence: A simple procedure to avoid repeat kidney biopsies.

We highlight a method that is helpful in situations where the tissue sent for LM is inadequate whereas the tissue sent for IF showed glomeruli useful for interpretation. We utilized the leftover frozen tissue after the sections for IF were taken. This tissue was post-fixed in formalin for the purpose of light microscopic diagnosis. The glomerular pathology could be commented upon with a fair degree of accuracy and a repeat biopsy was avoided in 74.7% of the cases. However, the tubules showed marked fixation artefact and tubular pathology was distorted. This procedure can help to reach a correct diagnosis in large percentage of cases otherwise labeled as inadequate biopsy and hence, save the patient from the trauma of a repeat biopsy.

Cytodiagnosis of alveolar soft part sarcoma: Report of two cases with special emphasis on the first orbital lesion diagnosed by aspiration cytology.

Alveolar soft part sarcoma (ASPS) is a rare neoplasm of uncertain cell of origin. Known to occur in adolescents and young adults, this tumor usually involves the muscles and deep soft tissues of the extremities and trunk. Orbital localization is rare and not yet subjected to cytological assessment, as per our literature search. We present here two cases of ASPS diagnosed by aspiration cytology, one in the orbit and the other in the lower extremity. The cells displayed abundant clear to finely vacuolated cytoplasm, often with disrupted margins and flowing of the cytoplasmic material; prominent nucleoli and scattered bare nuclei were also seen in the background. Two close cytological differential diagnoses include metastatic renal cell carcinoma and paraganglioma. Intracytoplasmic periodic acid schiff (PAS) positive, diastase-resistant, needle-shaped crystals and corresponding rhomboid crystals with regular lattice pattern on ultrastructure are the hallmarks of this neoplasm. Due to its slowly progressive clinical course and poor outcome, preoperative diagnosis of ASPS through fine-needle aspiration cytology may be essential for deciding therapy, especially in rare and difficult locations like orbit, where adjuvant radiation may not be possible.

Thickness of glomerular and tubular basement membranes in preclinical and clinical stages of diabetic nephropathy.

AIMS: This study aimed to elucidate the early renal changes in diabetes mellitus (DM) with and without clinical symptoms related to renal damage. METHODS: Renal biopsy was studied in 25 patients (14 with microalbuminuria and 11 with albuminuria) both by light and electron microscopies (LM and EM, respectively) for renal changes and morphometry was performed to study glomerular and tubular basement membranes (GBM and TBM, respectively) width using a Soft Imaging System GmBH (analysis 3). RESULTS: A significant increase was noted in the mean GBM and TBM thickness in both the preclinical and clinical groups compared to the control group. The changes in the TBM were noted to be predominant in both preclinical and clinical patients. CONCLUSIONS: This study indicates the importance of morphometric evaluation of the GBM and TBM width in the elucidation of early renal damage in diabetic nephropathy, especially in the absence of LM changes. The significance of identification of early renal changes using morphometric techniques for better management of these patients requires further studies.

Management strategies for bilateral vestibular schwannomas.

BACKGROUND: Bilateral vestibular schwannomas (VS) are rare. Most patients in India present late in the course of illness with large tumors and disabling deafness. Clinical presentation and management goals are different from that of unilateral VS. AIMS: To highlight the differences in clinical presentations and surgical results of bilateral VS compared to unilateral VS; and, to propose a management strategy for these tumors with reference to tumor size, extent of growth and the presence or absence of hearing impairment. METHOD: This is a retrospective study of 16 patients with bilateral VS treated over 10 years in a tertiary referral hospital. Assessment of VIIth and VIIIth cranial nerve function, tumor size, volume and extent of growth was performed in all patients. The management strategy was based on Samii's classification of tumor extent. All patients were operated using a retromastoid suboccipital approach. Postoperative results were analyzed and compared with those of unilateral VS. RESULTS: The mean age of presentation was 25.7 years. Hearing impairment was the commonest symptom. Headache with features of raised intracranial pressure were present in 10 (62.5%) patients. Giant tumors were present in seven (43.7%) patients; large tumors in eight (50%) and a medium-sized tumor in one (6.3%). Total tumor resection was achieved in 13 patients and subtotal resection in two. One patient was managed conservatively and followed up with serial CT scans. On the contralateral side, one large tumor required total excision. One medium sized tumor underwent sub-capsular excision in an attempt to preserve hearing. The facial nerve was anatomically preserved in seven (46.7%) patients and in one, the cochlear nerve was anatomically preserved. There was no peri-operative mortality. CONCLUSIONS: Patients with bilateral schwannomas are younger, have larger lesions, poorer preoperative hearing and are more likely to lose either auditory and/or facial nerve function during attempted total resection of the tumor. Classifying the tumors into two groups by extent, that is, tumors extending to the cerebellopontine angle cistern (T1-T3a) and, tumors extending to or compressing the brainstem (T3b to T4b), allows the surgical strategy to be defined.

Recurrent and residual juvenile angiofibromas.

INTRODUCTION: In the surgical management of juvenile nasopharyngeal angiofibromas the possibility of recurrences and residual tumours is always there. This study was undertaken to predict the prognostic factors determining recurrence of juvenile nasopharyngeal angiofibroma and to find out the usual sites of these tumours. MATERIAL AND METHODS: The medical records of 95 patients with histologically proven juvenile nasopharyngeal angiofibroma were reviewed retrospectively. The commonest surgical approach used was a combined transpalatal and transmaxillary approach with a lazy S incision. A conservative lateral infratemporal approach was used in three cases. RESULTS: Complete removal of the juvenile nasopharyngeal angiofibroma was achieved in 78 (82 per cent) of the cases in a single operation. A residual tumour was found in 17 (18 per cent) cases and recurrences occurred in 13 (13.7 per cent) cases. CONCLUSIONS: Extensions into the pterygoid fossa and basisphenoid, erosion of the clivus, intracranial extensions medial to the cavernous sinus, invasion of the sphenoid diploe through a widened pterygoid canal, feeders from the internal carotid artery, a young age and a residual tumour were risk factors found associated with recurrence of juvenile nasopharyngeal angiofibroma.

Emergency cardiopulmonary bypass for impassable airway.

INTRODUCTION: Some medical emergencies need compromised airway management as the first measure. Most of these cases are first seen by an ENT surgeon, whose proper evaluation and timely intervention can prove decisive. Knowledge of alternatives for airway management can prove life-saving, although these may require the active involvement of other specialities. CASE REPORTS: Two patients, a 27-year-old man and a 31-year-old woman, presented in respiratory distress with cyanosis. Each had a pedunculated mass in the lower trachea above the carina, with about 90 per cent tracheal lumen obstruction. They were managed successfully with femorofemoral cardiopulmonary bypass and restoration of airway. CONCLUSION: Femorofemoral cardiopulmonary bypass can be a relatively safe option which gains time for airway management in such conditions. Knowledge of this procedure among ENT surgeons can lead to timely intervention, in properly selected cases, which can save valuable time.

Embolization of cranial/spinal tumours and vascular malformations with hydrogel microspheres. An experience of 69 cases.

OBJECTIVE: To evaluate polymethyl methacrylate hydrogel microspheres (HMs) as an embolization material in the management of hypervascular craniofacial and spinal lesions. MATERIAL AND METHODS: Sixty-nine patients with vascular lesions of the craniofacial and spinal regions underwent embolization with HM. The pathologies included craniofacial tumours (n=38), cranial arteriovenous malformations (AVMs) (n=7), dural AVM (n=1), cavernous carotid fistula (n=1), spinal tumours (n=7), spinal AVMs (n=6), orbital lesions (n=4) and scalp AVMs (n=5). Surgery was done in 56 patients. The blood loss at surgery, tumour shrinkage, surgical cleavage and ease of removal of tumour was noted from the records. Histopathology was available in 39 patients. A follow-up of 3 months to 6 years was available in 13 patients in whom embolization was the sole treatment. Surgical and histopathological findings were correlated with angio-embolization findings. RESULTS: HMs were easy to inject through the microcatheter with good control. Good devascularization was obtained in 61 patients and partial in 8 patients. Two patients developed complications due to presence of anastomoses between intra- and extracranial circulation and 1 patient due to tumor swelling. Histopathology showed presence of HMs in all the lesions, with minimal inflammatory reaction in 2 patients. Patients with spinal lesions treated with embolization only stabilised in neurologic deficits. CONCLUSION: HMs are highly suitable as embolization agents in the management of craniofacial and spinal hypervascular lesions.

Extended frontobasal approach to the skull base.

The extended frontobasal approach provides an adequate midline exposure from the anterior cranial fossa to the sphenoclival region. Between November 1991 and August 1999, 13 patients with extensive anterior and anterolateral skull base tumours extending to supra and parasellar regions, cavernous sinus and sphenoclival regions were operated upon using this approach alone (7 patients) or in combination with subtemporal -infratemporal (4 patients) or transfacial (2 patients) approaches. Gross total excision was performed in 8 patients while in 4 patients with malignant tumours and in a patient with extensive skull base fungal granuloma, only partial excision was possible. Basal repair was performed using pedicled pericranium, temporalis muscle or fascia lata. The complications included increase in the cranial nerve paresis, endophthalmitis, facial oedema, CSF leak, frontal haematoma and internal carotid artery injury. This study reviews the operative technique, the indications and the complications of extended frontobasal approach.

Tuberculosis of the skull. A case report and review of the literature.

A case of tuberculosis of frontal, ethmoid, and sphenoid bones with intracranial extension is presented. The patient had presented with a history of painless left frontal swelling for the previous 7 months. A diagnosis of tubercular etiology was established with the histopathology of the biopsy specimen. The patient was kept on antitubercular treatment for 18 months. She responded well, with a marked resolution of symptoms and radiologic findings. At the end of treatment, there was no clinical or radiological evidence of disease. At 6-month and 1-year follow-ups, there was no evidence of recurrence or reactivation of the disease.

Brain stem evoked responses in patients with diabetes mellitus.

Diabetes mellitus is a systeihic disorder which targets multiple organs. The neurological involvement is not only in the form of peripheral neuropathy, but may also lead to central neuropathy. To evaluate the presence of central neuropathy auditory brain stem evoked responses were recorded from 25 normal hearing diabetic subjects aged 28 years to 49 years (Mean age 44.28 years) at 2KHz, 4KHz, & 4KHz, frequencies. The results obtained were compared with those obtained from 10 subjects with normal hearing of matched age and sex. In diabetic subjects, abnormal wave latencies were correlated with blood glucose level, duration of illness and peripheral neuropathy.The absolute latencies and inter peak latencies were significantly impaired (P<.001) in diabetic subjects as compared to control subjects at 2, 4, & 6KHz frequencies. The incidence of delayed wave latencies was 64%, 72%. & 84% at 2KHz, 4KHz, & 6KMz respectively suggesting that if brain stem evoked response audiometry is conducted at higher frequency like 6KBz in diabetic patients, the involvement of central neural axis can be detected earlier. This study is the first to demonstrate that brain stem evoked response audiometry is a useful non-invasive test for earlier detection of damage in central neural axis in patients of diabetes mellitus. There is no relationship between the delayed wave latencies and the blood glucose level, however there exists a significant relationship between the delayed wave latencies and the duration of disease & peripheral neuropathy.

Nasoethmoid schwannoma with intracranial extension. Case report and review of literature.

Schwannomas are very rare in the nose and paranasal sinuses; their presence both intra-and extracranially is still rarer. Here we present a case of nasoethmoid schwannoma with intracranial extension into anterior cranial fossa. Clinical, radiological, pathological and operative findings are discussed and the literature is reviewed. We recommend bifrontal craniotomy for removal of intracranial and nasoethmoid extensions of this tumor.

Spontaneous evacuation of cerebellar abscess through the middle ear. A case report.

Otogenic brain abscesses are a significant cause of mortality and morbidity in developing countries. Usually they occur either by distant thrombophlebitis of cerebral veins or by direct extension in an unsafe type of chronic suppurative otitis media. This case of cerebellar abscess was prepared for surgical excision, when sudden evacuation of pus through the left middle ear resolved the abscess and clinical features in the patient. No surgical intervention was required in this patient. The case under discussion is unique and unreported for its spontaneous evacuation through the middle ear.

Juvenile angiofibroma: review of a case series and role of embolization.

Here 15 cases of advanced Juvenile angiofibroma are presented. Advantages of wide tumour exposure and preoperative embolization are discussed.

Rhinocerebral invasive aspergillosis.

Here we present 10 cases of rhinocerebral aspergillosis. In this study we included only invasive type of cases. In 4 of these disease had extended into the brain parenchyma and in remaining cases diseases had extended intracranially but dura was not invaded. Details about the operative procedure and followup is presented. Till date only 3 of these cases are surviving.

Juvenile angiofibroma transpalatal approach for intracranial extensions.

Here we present transpalatal approach for removal of intracranial extensions of Juvenile Angiofibroma (JA) of nasopharynx. Modification of standard transpalatal approach, it is possible to remove extracranial as well as small intracranial tumour. Details of technique, advantages and limitations are presented.

Bera in normal neonates and infants: (Some observations on maturation of auditory pathways).

This study includes eight normal, not at-risk for deafness, neonates and infants of age ranging from 2 days to 1 year. BERA was done at 2 kHz. frequency at 80 dB intensity. In the majority of the subjects, only wave I, II, III and V could be definitely identified. It was observed that latencies of waves decreased as age of neonate/infant increased. Decrease of latency was more marked in first 6 months of life (wave V from 7.2 ms to 6. / ms) as compared to next six months (wave V from 6. 1 ms to 5.9 ms). This could be because of rapid myelination in the first six months of life.

Acoustic biast trauma.

In this study 26 cases of blast injury to ear were studied. Both ears were affected in 9 cases and therefore the number of ears studied being 35. The audiological findings along with the treatment and a followup of 2 years is presented.We found that mixed deafness was commonest and the sensorineural element of the hearing loss started recovering before conductive element, but recovery slowed down later on and was incomplete in most cases. Approximation of torn fragments of tympanic membrane improved its healing. Vertigo lasting for 1-7 days was present in 46.15% of cases. Only one patient had perilymph fistula which was repaired.

Rhinological complications of sublabial transseptal transsphenoidal surgery for sellar and suprasellar lesions: prevention and management.

Transseptal transsphenoidal surgery is the most widely accepted operative procedure for sellar and suprasellar lesions. About 35% out of fifty-four cases operated by this procedure at our centre had rhinological complications. Possible mechanism involved and their prevention and management is discussed herewith.