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Biomedical subjects

G Menon

Publications and source records attributed to G Menon.

At least 19 recordsLinked to original sources
PubMed2003

Development of a novel Agrobacterium-mediated transformation method to recover transgenic Brassica napus plants.

We report here an in planta method to produce transgenic Brassica napus plants. The procedure included Agrobacterium-mediated inoculation of plants at various development stages along with a vacuum infiltration step. The flowering stage appeared to be the most receptive stage for transformation and production of transgenic plants. In some cases, the flowering stage was induced either by cold treatment or by high density planting. Molecular and genetic analysis revealed that single and multiple copy events were generated and that the transgenes were transmitted to the T1 and T2 progeny in a Mendelian fashion.

Base Sequence↗
PubMed2003

Post partum phaeochromocytoma.

A case of phaeochromocytoma which presented post partum is reported. Uneventful pregnancy and delivery of a healthy infant were followed by acute respiratory and cardiovascular deterioration of the mother. Despite intervention our patient died 36 h after first presentation. Diagnosis of phaeochromocytoma was confirmed post mortem.

Journal Article↗
PubMed2003

Neonatal long lines.

Explore the source record for details and available documents.

Bacterial Infections↗
PubMed2003

False aneurysm of cavernous carotid artery and carotid cavernous fistula: complications following transsphenoidal surgery.

We present two cases of carotid injury during transsphenoidal surgery for pituitary adenoma. While in one of the cases it resulted in the formation of a false aneurysm of cavernous carotid artery, in the other patient, a carotid cavernous fistula (CCF) formed. The false aneurysm was managed by surgical trapping and the patient had an uneventful recovery. The CCF was initially managed with balloon embolization. The balloon got deflated and resulted in a false aneurysm with persistent CCF. This was occluded with Guglielmi Detachable Coils (GDC). The management options are discussed and relevant literature is reviewed. We emphasize the importance of an early cerebral angiography to know the status of the injured carotid artery and formation of false aneurysm / fistula.

Adenoma↗
PubMed2001

Dissecting intracranial vertebral artery aneurysms.

Dissecting aneurysms of the intracranial arteries are exceedingly rare vascular lesions that can produce acute cerebral or brain stem infarction in young healthy adults. They carry a high mortality rate. Two cases of dissecting vertebral artery aneurysms that presented with bleed, were successfully operated by trapping and excision of the dissecting segment. Both dissecting aneurysms were located distal to PICA origin. Both the patients developed post operative lower cranial nerve paresis and one developed lateral medullary syndrome, which improved subsequently. Dissecting aneurysms presenting with bleed should be surgically managed by trapping and excising the involved segment sparing the PICA origin or by interventional radiological techniques. Revascularisation procedures should be considered in addition to trapping of the main vertebral segment if PICA is involved in the trapped segment. The diagnostic and therapeutic difficulties associated with dissecting vertebral artery aneurysms and the controversies regarding their management have been reviewed.

Adult↗
PubMed2001

Mixed tumour of schwannoma and meningioma in a patient with neurofibromatosis-2 : a case report.

The co-existence of schwannoma and meningioma as a mixed intracranial tumour is uncommon and so far only eight cases have been published in the literature. Because of rarity, we report a unique case of mixed tumour having schwann cell and meningeal components, in a patient with neurofibromatosis type -2 (NF-2). The possible mechanisms for the occurrence of these mixed tumours are discussed.

Adult↗
PubMed2000

Measurement of relative output for 90Sr ophthalmic applicators using radiochromic film.

The treatment of various superficial lesions of the eye has, for many years, been conducted using strontium 90 (90Sr) ophthalmic applicators that have a steep dose gradient near their surface. A new applicator acquired by a treatment facility must have its output compared with that of any older applicators already in use to ensure consistent treatments. These measurements may be done using available dosimeters such as film and thermoluminescent detectors. Our work made use of radiochromic film and a document scanner to perform relative output measurements for 4 different 90Sr ophthalmic applicators acquired from the same manufacturer (Amersham Healthcare, Arlington Heights, IL) over a span of 28 years. Relative outputs were found to vary by < 10% with respect to the manufacturer's values, which is well within the uncertainty limit for absolute output of 20% specified by the manufacturer. The film measurements were verified using thermoluminescent dosimeters. Radiochromic film was also used to obtain a percentage depth dose curve and a 2 dimensional isodose distribution in a plane perpendicular to the active surface for the newest applicator (SIA 20).

Eye Diseases↗
PubMed2000

Efficacy and tolerability of olanzapine in elderly patients with psychotic disorders: a prospective study.

Olanzapine is a novel antipsychotic effective in reducing positive and negative symptoms of schizophrenia and with a safe side-effect profile. Premarketing trials, however, included only a few elderly patients. Further data are needed regarding the effects of olanzapine in the elderly and those with comorbid medical illness. In this pilot study, 11 hospitalized patients (age range 60-85 years) who manifested symptoms of psychosis related to schizophrenia and schizoaffective disorders were treated with olanzapine (dose range, 5-20 mg/day). Efficacy and safety were assessed by the Positive and Negative Syndrome Scale (PANSS), Clinical Global Impression Scale (CGI), Extrapyramidal Symptom Rating Scale (ESRS), Mini-Mental State Examination (MMSE), Calgary Depression Scale For Schizophrenia (CDSS), EKG, physical examination, and various laboratory tests. Seven patients responded to treatment and all of them showed improvement in both positive and negative symptoms, with greater reduction in positive symptoms. Treatment was discontinued in 2 patients whose symptoms showed no improvement or worsened. The CGI showed significant improvement in 9 patients, remained the same in 1, and worsened in 1 patient. ESRS showed significant reduction from baseline to final visit. Of the 10 patients who cooperated for MMSE, 9 had improved scores. The CDSS showed significant reduction in scores from baseline to final visit. No significant changes were noted in laboratory tests, prolactin levels, EKG, and physical examination. Concomitant administration of lorazepam, carbamazepine, divalproex sodium, and lithium carbonate caused no adverse consequences. The reduction of positive and negative symptoms, lack of significant extrapyramidal symptoms and other side effects, and lack of any significant drug interaction suggest that olanzapine may be a safe and effective antipsychotic medication in the elderly.

Aged↗
PubMed2000

Medial trigonal arteriovenous malformations.

A retrospective analysis of 48 patients of medial paratrigonal arteriovenous malformations (AVMs) which constituted 18% of the total 258. AVMs surgically managed in our institute for 16 years was carried out to study their clinical presentation, radiological features, operative approaches and functional outcome. While hemorrhage was the initial presenting symptom in 35, it was longstanding headache in 10, focal seizures in two and progressive weakness in one. However, 41 of these presented with bleed at the time of admission to our hospital and in 15 there was history of multiple bleeds. Twelve and eleven patients had field cut and hemiparesis respectively. Arterial supply to the malformation was quite uniform with posterior (43 patients) and anterior cerebral (25 patients) being the most frequent source. Venous drainage was predominantly into the galenic system (70%). Preoperative embolization was carried out in six patients. While the AVM was excised through a parasagittal interhemispheric approach in 34 patients, the nidus was approached through a direct transcortical (superior parietal lobule) approach in fourteen patients. There was only one operative mortality. Twelve patients whose preoperative fields were normal developed field cut postoperatively. An improvement of the preoperative field deficit was noted only in one patient. While eight of the ten patients with preoperative weakness improved and remained independent the remaining two were moderately disabled. Only two of the 10 patients who developed postoperative weakness remained severely disabled. Our operative results suggest that these AVMs which are prone to recurrent bleeds can be resected with acceptable morbidity. Hemianopia resulting from bleed or surgery is unlikely to improve.

Adolescent↗
PubMed1998

Practical approach to analgesia and sedation in the neonatal intensive care unit.

The anatomic and physiological bases for nociception are present even in very preterm neonates. Neonates show the same behavioral, endocrine, and metabolic responses to noxious stimuli as older subjects. Preterm infants appear to be more sensitive to painful stimuli and have heightened responses to successive stimuli. Infants receiving intensive care are subjected to frequent stressful procedures and also chronic noxious influences related to the environment of care. Inflammatory conditions such as necrotizing enterocolitis may also cause pain. Untreated pain in babies is associated with increased major morbidity and mortality. Nonpharmacological interventions, including environmental modification and comforting during procedures reduce stress. Intravenous opiates are the mainstay of pharmacological analgesia. A pure sedative agent can provide physiological stability in settings in which there are less acutely painful stimuli or when there are adverse effects from, or tolerance to, opiates. Local anesthesia of skin and mucous membranes is helpful for invasive procedures. Antipyretic analgesics such as acetaminophen have a role in inflammatory pain.

Analgesia↗
PubMed1998

Separation of the S(+) and R(-)-enantiomers of tiagabine.HCl and its two chiral precursors by chiral chromatography: application to chiral inversion studies.

Chiral HPLC methods were developed and validated for tiagabine.HCl and its two chiral precursors to determine the chiral purity of the three compounds to ensure the quality of the final product which is used as a new antiepileptic drug. Tiagabine.HCl was derivatized with 1-napthalenemethylamine and was chromatographed on a Pirkle type phenyl glycine column with a mobile phase of 69:31, 0.1 M ammonium acetateacetonitrile (v/v). The two chiral precursors were chromatographed on a Chiralcel-OG column with a mobile phase of hexane, isopropanol etc. Each of the three HPLC methods have a selectivity factor (alpha) of 1-2 or higher. The validation of the methods was done by conducting standard addition and recovery studies of the S(+)-enantiomers in the samples. The %RSD of all three methods were < 5 with a limit of quantification of 0.05% (peak area) or lower. By using these methods, a study was conducted to investigate the effect of pH, temperature, and trace levels of transition metals such as Fe3+, Co2+, and Ni2+ on the conversion of R(-)-enantiomer to the S(+)-enantiomer of tiagabine.HCl and its two chiral precursors. The results of this study demonstrated that the two chiral precursors of tiagabine.HCl under reflux conditions are more sensitive to chiral inversion than tiagabine.HCl. Under reflux conditions, in the presence of trace metal ions and different pH, approximately 10, 11, and 1% of the R(-)-enantiomer was converted to the S(+)-enantiomer for ethyl nipecotate, ethylester of tiagabine, and tiagabine.HCl, respectively. However, at room temperature, tiagabine.HCl appears to be less chirally stable than its two chiral precursors. Approximately 0.4% R(-)-enantiomer of tiagabine.HCl was converted to the S(+)-enantiomer at room temerature and acidic conditions. Under similar conditions, the S(+)-enantiomer of ethyl nipecotate and ethylester of tiagabine.HCl was < 0.05%. The initial S(+)-enantiomer content for all three compounds was < 0.1%.

Anticonvulsants↗