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Biomedical subjects

D S Mishra

Publications and source records attributed to D S Mishra.

At least 19 recordsLinked to original sources

Posterior mediastinal teratomas.

Posterior mediastinal teratomas are rare. We report this entity in a five year old boy. A review of literature of eighteen cases is presented.

Child, Preschool↗

Existence of a mannitol hydrate during freeze-drying and practical implications.

We report thermal and crystallographic evidence for a previously unknown mannitol hydrate that is formed in the process of freeze-drying. The mannitol hydrate was produced by freeze-drying pure mannitol solutions (1-4% w/v) using the following cycle: (1) equilibration at -5 degreesC for 1 h; (2) freezing at -40 degreesC; (3) primary drying at -10 degreesC for 15 h; and (4) secondary drying at 10 degreesC for 2 h and then 25 degreesC for 5 h. This crystal form was also observed upon freeze-drying in the presence of sorbitol (1% w/v). The mannitol hydrate showed a distinct X-ray powder diffraction pattern, low melting point, and steplike desolvation behavior that is characteristic of crystalline hydrates. The mannitol hydrate was found to be metastable, converting to anhydrous polymorphs of mannitol upon heating and exposure to moisture. The amount of the mannitol hydrate varied significantly from vial to vial, even within the same batch. The formation of mannitol hydrate has several potential consequences: (1) reduced drying rate; (2) redistribution of the residual hydrate water during accelerated storage to the amorphous drug; and (3) vial-to-vial variation of the moisture level.

Calorimetry, Differential Scanning↗

An evaluation of myelography with non-ionic water soluble contrast medium-iohexol.

Iohexol myelography was performed in 25 cases of suspected spinal cord compression. Out of these, 24 cases gave optimally informative myelogram, while one case showed quasi-informative myelogram. Myelographic efficacy regarding the level of lesion was correct in all cases. On final evaluation 15 cases were diagnosed as extradural lesions, 9 cases as intradural extramedullary type and one case as diastematomyelia. Only single case which was diagnosed as intramedullary lesion on myelography was, in fact, an extradural lesion. There were only minor side-effects in the form of headache and paraesthesia in the lower limb. It was concluded that iohexol is a safe contrast medium with high efficacy and minimal side-effects for the total examination of spinal canal.

Contrast Media↗

Determination of the glass properties of D-mannitol using sorbitol as an impurity.

Due to its strong tendency to crystallize, the glass properties of mannitol cannot be measured directly. However, because mannitol can exist in a fully or partially amorphous state in drug formulations, it is important to determine the glass properties of mannitol. We obtained the glass properties of mannitol by introducing a small amount of sorbitol, an isomer of mannitol, to delay the onset of crystallization. Extrapolation to zero sorbitol concentration yielded the following properties for the mannitol glass: Tg onset = 10.7(o)C, Tg midpoint= 12.6( o)C, Tg end = 18.4 degreesC and DeltaCp = 1.27 J/g/K. In addition, we estimated the following parameters of the mannitol glass from the width of glass transition using the results of Moynihan (J. Am. Ceram. Soc. 1993, 76, 1081) and Angell (J. Phys. Chem. 1994, 98, 13780): DeltaH (at Tg onset) = 103 kcal/mol, D = 11, and T0 = 222 K. The value of T0 is consistent with the Kauzmann temperature TK (236 K) obtained calorimetrically. The properties of the mannitol glass may be useful for predicting the behavior of amorphous mixtures containing mannitol.

Calorimetry, Differential Scanning↗

Evaluation of computed tomograms in paediatric head trauma.

Computed tomograms of 107 patients of head trauma in the paediatric age group were evaluated. Generalised brain swelling (44%) and falx sign (44%) were the commonest findings observed in the computed tomograms. The overall mortality was 16.8% of which all except one were those with Glasgow coma scale between 3 and 7.

Accidental Falls↗

Comparative evaluation of computed tomography and cerebral angiography in the management of subarachnoid haemorrhage.

Plain and contrast enhanced computed tomography (CT) scan of brain and cerebral angiography were done in 20 subjects of subarachnoid haemorrhage (SAH), diagnosed on the basis of clinical parameters and proved by cerebrospinal fluid (CSF) examination. Plain CT scan of brain confirmed the diagnosis of SAH in all the 20 (100%) cases, but was able to demonstrate the cause of SAH in 11(55%) cases only. Contrast CT scan provided additional information in 7 more cases. CT was also able to demonstrate the site and extent of bleeding, evidence of intraventricular bleeding and hydrocephalus. Cerebral angiography done in all the cases, confirmed the diagnosis in 14 (70%) cases diagnosed on CT and was able to give additional information in 4 more cases. It also showed excellent vascular details which were not possible with CT scan. It is concluded that enhanced CT scan should be done first in all the cases of SAH for preliminary scouting and angiography should be done where CT scan gives incomplete information or where surgical management is contemplated. Both the investigations were found to be complementary to each other.

Adolescent↗

Role of arthrography in non-traumatic painful wrist.

The arthrographic examination was carried out in 25 patients with non-traumatic painful wrist of more than 6 weeks duration. Plain x-rays were non-contributory in making any diagnosis in 20 cases. Arthrography was performed even when plain x-rays were normal and it revealed the soft tissue abnormalities and early phases of cartilage destruction not visible on routine roentgenograms. The extent of synovial involvement demonstrated on arthrography proved useful when synovectomy was planned. After operation pain and swelling disappeared and functions of the joint improved considerably.

Arthritis, Rheumatoid↗

Morphological changes in cooked longissimus dorsi muscle of pig, buffalo, sheep, goat and poultry.

In an effort to establish the morphological differences between the cooked muscles of pig, buffalo, sheep, goat and poultry longissimus dorsi were examined. Cooking at 100 degrees C produced shrinkage of muscle fibres in all species. The demarcation of the fascicles was also lost. Cooking at 121 degrees C destroyed even the granulated structure of collagen, reducing it to an amorphous state. The transverse striations were lost and the muscle fibres showed cracking, breaking and splitting. In relation to the control the per cent values of the cross-sectional area of the muscle fibre after treatment at 100 degrees C decreased by 28.6% in pig, 17.8% in buffalo, 20.4% in sheep, 24.3% in goat and 34.8% in poultry, whereas the respective values after cooking at 121 degrees C were 38.3%, 28.6%, 32%, 33.9% and 44.1%. Besides, the muscle fibre diameter in all species was also reduced after cooking. The number of muscle fibres and fascicles per mm2 were found to increase after cooking at 100 degrees C and 121 degrees C.

Animals↗

Morphological differences in longissimus dorsi muscle of pig, buffalo, sheep, goat and poultry.

With a view to establish morphological differences between the muscles of pig, buffalo, sheep, goat and poultry, longissimus dorsi were examined. The average fibre cross-sectional area, average fibre diameter, number of fibres per unit area, fascicle size and number of fascicles per unit area have been studied. The size of the muscle fibres showed a decrease in the following order: pig, buffalo, sheep, goat and poultry. In poultry the muscle fibres were thinner and the fibre density values were greater in comparison to other species. The fibres were the coarsest in the pig. A slight difference in the fascicle size between the different species could be appreciated, the pig fascicles being generally large.

Animals↗