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Biomedical subjects

G Dua

Publications and source records attributed to G Dua.

12 recordsLinked to original sources
PubMed2006

Radiological classification of anterior skull base anatomy prior to performing medial orbital wall decompression.

PURPOSE: To study a radiological classification, originally described by Keros in 1965, which provides an objective assessment of anterior skull base anatomy relevant in patients undergoing external medial orbital decompression. MATERIALS AND METHODS: The classification is based on anatomical landmarks measured via coronal CT-scan. The patients are divided into 3 Keros categories based on their olfactory fossa depth; Keros 1 (1-3 mm), Keros 2 (4-7 mm) and Keros 3 (8-16 mm). A cross-sectional group of 32 consecutive patients on the hospital radiology database with coronal CT scans were classified according to the Keros system. RESULTS: All the patients fell into one of the three Keros categories. Anatomical associations of the Keros classification suggest that Keros 1 patients have the least risk of intracranial entry whilst Keros 3 patients carry the greatest risk. CONCLUSION: Keros classification provides an objective assessment of anterior skull base anatomy and can therefore guide the surgeon on the superior extent of medial wall bone removal during orbital decompression. This may help improve the safety profile of the procedure.

Decompression, Surgical↗
PubMed2006

Central nervous system metastases of pulmonary adenocarcinoma mimicking neurofibromatosis type 2.

We report a case of a 51-year-old man presenting with rapidly progressive unilateral tinnitus, hearing loss and imbalance. Neuroimaging revealed bilateral VIIIth cranial nerve masses and multiple cerebral and spinal cord lesions that were interpreted as being acoustic schwannomas and multiple meningeomas. An initial tentative diagnosis of neurofibromatosis type 2 (NF2) was made. Both clinical and radiological evolution were atypical for NF2 and the initial diagnosis of NF2 was questioned. Additional technical investigations demonstrated a pulmonary adenocarcinoma. Postmortem examination confirmed that this patient had multiple central nervous system metastases of a primary pulmonary adenocarcinoma, presenting clinically and neuroradiologically as a probable neurofibromatosis type 2. Clinicians should be aware of the rare possibility of central nervous system metastases mimicking NF2.

Adenocarcinoma↗
PubMed1998

Obstructive hydrocephalus as complication of a giant nonfunctioning pituitary adenoma: therapeutical approach.

We report the case of a 61-year-old male presenting with a giant nonfunctioning pituitary tumour extending into the third ventricle and thereby causing obstructive hydrocephalus. The main complaints consisted of disturbed vision and somnolence. The patient was initially treated by ventriculoperitoneal shunting, with immediate improvement of his mental status. Transcranial resection of the tumour was performed shortly thereafter, but only a limited part of the tumour could safely be removed. By immunohistochemistry the diagnosis of gonadotroph adenoma was made. After the operation, the patient's vision deteriorated temporarily. Because of the risk of further damage to the optic nerve, radiation therapy was postponed. Instead, treatment with the long-acting dopamine agonist cabergoline was instituted, which resulted in a gradual improvement of vision. Two years later a transsphenoidal operation was performed because of acute worsening of the visual fields due to central tumour necrosis with slight volume expansion. Vision improved considerably after surgery. Radiotherapy is scheduled in the near future. This case is an illustration of the complications of giant nonfunctioning pituitary adenomas. The therapeutical approach to obstructive hydrocephalus in these instances is reviewed.

Adenoma↗
PubMed1997

Synthesis of glycosides in which the aglycon is an N-(hydroxymethyl)amino-1,3,5-triazine derivative.

The synthesis of analogues of the anti-tumour drug 2-[N-(hydroxymethyl)methylamino]-4,6-bis(dimethylamino)-1,3,5-triazine (HMPMM) in which the OH or a dimethylamino group is replaced by a carbohydrate has been explored. Triazinyl beta-glycosides were readily prepared by reaction of sugars with trimethyl-triazinylammonium salts. These were made with one or two methylamino groups on the triazine for reaction with formaldehyde to give the cytotoxic NMeCH2OH group. However, reaction of the triazinyl glycosides with formaldehyde gave complex intractable mixtures. When the carbohydrate portion was changed to the fully protected 2,3,4,6-tetra-O-acetyl glucose a good yield of the 2-[N-(hydroxymethyl)methylamino]-4-(dimethylamino)-1,3,5-triazin-2 -yl tetra-O-acetyl beta-glucoside was obtained. However, de-acetylation using sodium methoxide also removed the N-CH2OH group. We are investigating protection of the base-sensitive N-CH2OH group as trialkylsilyl and benzyl ethers and are looking at de-acetylation methods that are more selective. We have prepared glycosides in which the sugar is joined through the oxygen of the NMeCH2OH group. Coupling of acetobromoglucose with HMPMM catalysed by silver salts was not successful. Although methyl and cyclohexyl derivatives of HMPMM may be produced in high yields by reaction of HMPMM with methyl and cyclohexyl alcohols under acidic catalysis, production of glycosides in this way gave poor yields. MNDO calculations on reactions of HMPMM helped us devise improved reaction conditions for the condensation of 2,3,4,6-tetra-O-acetyl glucose with HMPMM and its derivatives. The best procedure to generate one of the target glycosides is to react 2,3,4,6-tetra-O-acetyl glucose and formaldehyde with 2-methylamino-4,6-bis(dimethylamino)-1,3,5-triazine. The beta-glycoside product was de-acetylated using potassium carbonate in dry methanol.

Acetylation↗
PubMed1995

Pituitary metastasis mimicking a pituitary adenoma. A description of two cases.

The cases of two elderly women treated for temporal hemianopsia due to a large pituitary mass with suprasellar extension are presented. In both cases, the clinical picture, without diabetes insipidus and cranial nerve paralysis, as well the neuroimaging and endocrinological investigation showing hypopituitarism, were suggestive of a non-secreting pituitary adenoma. In the first patient malignant tissue was unexpectedly encountered during transsphenoidal surgery. Anatomopathological investigation confirmed the presence of a metastasis of a breast carcinoma for which she had been treated 17 years earlier. In the second patient, a preoperative chest X-ray before transsphenoidal surgery revealed an asymptomatic bronchial tumour. Subsequently a squamous cell carcinoma with a metastasis in the pituitary was confirmed. These two cases illustrate the fact that a pituitary metastasis can closely mimic a pituitary adenoma. Even in the absence of suggestive symptoms such as diabetes insipidus and/or cranial nerve paralysis the possibility of metastatic disease in the differential diagnosis of a pituitary mass should always be considered.

Adenocarcinoma↗
PubMed1994

High cervical pain and impairment of skull mobility as the only symptoms of an occipital condyle fracture. Case report.

Occipital condyle fractures are rarely reported in survivors of trauma. Most cases involve patients with a major head trauma, lower cranial nerve palsy, and/or suspected lesions demonstrated on plain x-ray films of the skull or cervical spine. The authors describe a traffic-accident victim in whom an atlanto-occipital joint lesion was suspected based only on mobility investigation of the skull. Axial high-resolution computerized tomography of the atlanto-occipital joint showed a fracture of the right occipital condyle.

Adult↗
PubMed1991

Localized craniofacial fibrous dysplasia in a young girl.

We consider here the case of a young girl presenting a cystic bone mass in the left orbital roof. Although standard X-rays at first were not convincing, the findings on the CT examination and the histological aspect of the mass were typical of fibrous dysplasia. Although the exact diagnosis of fibrous dysplasia can only be made upon precise histological examination, radiological, and more specifically CT findings, may indicate this pathology.

Child↗
PubMed1988

Spinal angiomas as a cause of non-traumatic paraplegia: case report.

A case is presented of a 17-year-old boy who developed paraplegia after a sudden low back pain, like a 'stab in the back', with radicular radiation into the lower limbs. No trauma preceded the onset of symptoms. The diagnosis was finally made by neuroradiological investigations (magnetic resonance imaging (MRI), myelography and CT-scan). A review of the physiopathology of spinal angiomas, extra and/or intramedullary, by exclusion of vertebral (haem) angiomas, is made.

Adolescent↗
PubMed1987

Posttraumatic diabetes insipidus.

The authors report seven patients with fractures of the sella turcica. Four of them developed Diabetes Insipidus as a consequence of their traumata. The importance of computed tomography as a diagnostic procedure is paramount in order to make early diagnosis of this potential life-threatening condition possible.

Adolescent↗
PubMedDate not supplied

Bulbo-spinal lower motor neuron disease. Accumulation of neurofilaments in perikarya and axons.

Two sporadic adult cases of bulbo-spinal lower motor neuron disease are reported. In the first patient, the disease lasted 8 months and was characterized by a bulbar onset followed by a progressive cephalocaudal involvement of the lower motor neurons in the spinal cord. In the second case of 14 months duration, the cervical spinal cord was affected at first while medulla oblongata and lower limbs were involved later on. There was a slight increase of the protein contents in the CSF. Postmortem examination confirmed the selective involvement of the lower motor neurons in medulla oblongata and spinal cord with severe loss at cervico-medullary level in case 1 and more diffuse loss in case 2, in keeping with the clinical signs. Bodian silver staining and electron microscopy showed the accumulation of neurofilaments in anterior born cells' perikarya and in proximal axonal dilatations. The nosology of the disorder and the comparison with lesions found in various types of motor neuron disease in humans and animals are discussed.

Adult↗