Biomedical subjects
Publications and source records attributed to S Roy.
An attempt to percutaneously remove a guidewire from the inferior vena cava was hampered by kinks developing in the wire during snaring. A modified technique was adopted that permitted its retrieval, obviating the need for a formal venotomy.
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The present study was undertaken to evaluate the sequential BrdU-LI at weekly intervals upto four weeks in 18 primary explant cultures of meningiomas. This revealed three distinct patterns of growth which could be arbitrarily defined as 'degenerating' (group I), 'proliferating' (group II) and 'adaptive' (group III) types. Interestingly two cases of malignant and two of recurrent meningiomas fell into the 'degenerating' group I pattern. The possible explanations for the observed relatively higher in vitro LI values compared to lower in vivo values as reported in the literature and the theoretical implications of the three distinct patterns of sequential LI values are discussed.
The tumor microblood vessels (MBVs) of 25 cases of gliomas of varying grades were studied and compared with those in peritumoral region using both transmission and scanning electron microscopy (TEM and SEM). The TEM study revealed numerous villous projections with pinocytotic vesicles (PCVs) and large vacuoles (LVs) concentrated mainly at the luminal aspect in tumor MBVs which increased with increasing severity of edema. The peritumoral MBVs, in addition to showing some increase in villous projections on the luminal surface, also showed increased number of PCVs and LVs concentrated at the abluminal aspect with some of them even communicating with the extravascular space. The SEM study largely corroborated the TEM findings. The sites of formation of PCVs and LVs appeared as small pits or large craters on the luminal surface of the endothelial cells of tumor MBVs. We feel that the morphological evidence of increased permeability in tumor MBVs represents their role in the development of edema and that the occurrence of reverse pinocytosis in peritumoral MBVs is a distinct possibility which may be associated with resorption of edema fluid.
A 78-year-old man with a history of parathyroidectomy presented with hyperparathyroidism and tracheal obstruction. After excision of the mediastinal parathyroid cyst, his symptoms were completely relieved. The diagnosis, investigations, and management are discussed.
Medial hypertrophy of pulmonary arteries is caused by different acute and chronic diseases complicated by pulmonary hypertension and malformations of the lung. Thus the precise assessment of external radius and relative medial thickness are of importance for clinical and experimental pathology. Different concepts have been proposed to solve this problem. Wall thickness methods which can be applied to obliquely cut arteries suffer from the disadvantage that they require prior injection of vessels. Planimetric methods can be applied to not injected vessels but they fail in assessing the medial thickness of obliquely cut arteries. We describe a mathematical approach which renders even obliquely cut and simultaneously not injected pulmonary arteries able to be assessed accurately for medial thickness and external vessel radius. This method combines the advantages of wall thickness and planimetric methods. This new method and the established wall thickness and planimetric methods were applied to 178 rat pulmonary arteries and 412 injected and 401 not injected human pulmonary arteries. The statistical analysis revealed a satisfying reproducibility (Coefficient of correlation: 0.70-0.90) of the new method. The data assessed by the new method are similar to those of the established methods. We conclude our new method to be a significant tool for the assessment of vessel parameters even in small specimens including only few not injected vessels.
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The FO23C5 anti-carcinoembryonic antigen (CEA) F(ab')2 antibody was radiolabelled with 111In via diethylenetriaminepentaacetic acid (DTPA) and directly with 99Tcm by stannous ion and mercaptoethanol antibody reduction to compare the pharmacokinetics of these three agents. Four patients received 15 mCi 99Tcm-Fab' 1 week before receiving 1 mCi 111In-F(ab')2. Five additional patients received only the 99Tcm-Fab'. Radiochromatograms by high-performance liquid chromatographic (HPLC) analysis of serum and urine samples from patients receiving 111In were typical of those observed by us previously in connection with other antibodies. The identical analyses of samples from patients receiving 99Tcm showed no differences with the method of reduction and more complex radiochromatograms. In addition to peaks due to a mixture of labelled F(ab')2 and Fab' fragments and, occasionally, immune complexes, there were several peaks due to labelled cysteine and other small labelled species present in both serum and urine. The biodistribution of 99Tcm was as expected for a labelled Fab' fragment: relative to 111In, 99Tcm cleared rapidly from circulation and into kidneys and urine. Liver levels of 111In and 99Tcm were surprisingly similar at 1 day (12 versus 9% ID) although initial 111In levels were lower and increased while 99Tcm levels were higher and decreased. Spleen levels were also similar. In 4/9 patients receiving 99Tcm, hepatobiliary clearance was observed at levels which could confuse interpretation whereas this mode of clearance was observed in only 1/4 patients receiving 111In. Image quality was superior with 111In versus 99Tcm at 1 day postadministration as judged by counting rates and background activity whereas the opposite was true at 2-3 h postadministration.
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Explore the source record for details and available documents.
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The role of T-cell-derived cytokines in the regulation of Leishmania donovani replication was studied in a murine model. It was observed that in H-2d mice at the early and later stages of the disease IFN-gamma-secreting T cells predominate, whereas in between the above stages IL-4-secreting T cells predominate. Possibly, IL-4 abrogates the protective ability of IFN-gamma and thereby exponential parasite growth is ensured at the active stage of the disease. By contrast, H-2b mice were possibly incapable of inducing IL-4-secreting T cells and therefore parasite replication remains under control at any point post infection.
This study was undertaken to investigate in-vivo proliferative potential of neoplastic cells in 66 cases of gliomas of different histological types following peroperative intravenous infusion of bromodeoxyuridine (BrdU). Histological typing according to the recent modification of WHO classification did not often correlate with in-vivo cell kinetics. Among the different morphological features used for the classification, necrosis, mitosis, increased cell density and increased endothelial cell proliferation showed good correlation with tumor cell labelling index (LI) (p < 0.01-p < 0.001). A preliminary follow-up study of 36 cases for a period ranging from 9 to 36 mths suggested the possibility that higher in-vivo tumor cell LI might be associated with an early recurrence. Thus in vivo BrdU LI may supplement the histological classification of gliomas and together they may help in a better assessment of their growth rate, degree of malignancy and biological behaviour which in turn facilitate the planning of therapeutic management for individual cases.
In-vivo cell kinetics study following peroperative intravenous infusion of bromodeoxyuridine (BrdU) was done in 10 cases of primitive neuroectodermal tumors (PNET) and 44 nonglial tumors of different histological types. The histological features usually regarded as indicators of aggressive behaviour were examined in these tumors and correlated with in-vivo labelling index (LI). In the case of meningiomas, increased cellularity, pleomorphism and mitosis had no correlation with LI. Benign non-recurrent meningiomas usually showed LI < or = 1% (mean 0.6 +/- 0.3%) whereas recurrent and malignant meningioma showed higher LI (mean 2.6 +/- 0.5% and 2.8 +/- 0.4% respectively). Follow-up study suggested that meningiomas having benign histological appearance with LI > 1% might have increased chance of recurrence. In cases of PNETs among different histological features, mitosis and differentiation seemed to be related to the biological behaviour. Astrocytic differentiation was associated with lower rate of proliferation. In pituitary adenomas different hormone producing and null cell adenomas showed similar low proliferative potential (0.6 +/- 0.3%). Benign nerve sheath tumors, craniopharyngioma and choroid plexus papilloma showed low in-vivo LI of less than 1%. Thus the present study revealed the inadequacies of routine histological examination in assessing the aggressiveness of the nonglial tumors, especially meningiomas. In-vivo LI may be a good supplement to histological diagnosis as well as helping to assess the prognosis and accordingly the management of individual cases.
Astrocytomas of different grades of malignancy were cultured as primary explant and their sequential growth pattern, glial fibrillary acidic protein (GFAP) expression and labelling index (LI) using bromodeoxyuridine (BrdU) were assessed and correlated with the grade of malignancy of the original tumor tissue. Low-grade astrocytomas showed patterns of growth that diverged from anaplastic astrocytomas and glioblastoma multiforme. The GFAP expression decreased with increasing time in culture in all astrocytomas irrespective of the grading. Maximum GFAP was, however, expressed in the morphologically well-differentiated stellate cells. Contrary to expectations, lower BrdU LI was observed in glioblastoma multiforme in comparison to low-grade astrocytomas, which suggests some unidentified mechanism of differentiation in vitro for astrocytomas of higher grade of malignancy. Hence, in contrast to reported literature on the prognostic value of studies on primary cultures, the present study cautions the extrapolation of the in vitro findings for astrocytomas.
Changes in brain neurotransmitters [5-hydroxytryptamine (5-HT), norepinephrine, histamine and dopamine] were studied in Plasmodium berghei-infected mice and rats. 5-HT and norepinephrine contents of brain decreased significantly in Plasmodium berghei-infected mice and rats, but histamine and dopamine contents remained unaltered. Decreased 5-HT and norepinephrine contents of brain may play a role in cerebral vasodilatation in malaria.
The 4 payload crew members of the Spacelab Life Sciences 9-day space flight in 1991 were subjected to limited vestibular testing in flight as well as pre and post flight. Major differences in individual "perceptual style" appeared in their reaction to the visual-vestibular stimuli in the rotating dome experiment, and especially in the extent to which nondirectional tactile cues served to anchor the subjective vertical and body postural reactions. The ability of subjects to point to remembered target positions was degraded in space, which produced a tendency to point low in some subjects in flight. The eye movements and subjective response to sudden stops and head pitching following continuous spinning (dumping) were measured both in space and on the ground. Although subjective duration of inflight rotation for the dumping tests was shorter than that for the preflight tests, the postrotatory nystagmus, with or without head pitch, was lengthened in time constant relative to preflight. Ground tests, in addition to the flight experiments, investigated the changes following weightlessness in subjective and oculomotor reactions to whole body tilt, the ability to balance with eyes open and closed; leg muscles strength and stamina as related to posture; visual field dependence; and the perceptual and oculomotor reactions to horizontal linear acceleration. Several of these tests, as well as post-flight measures of motion sickness susceptibility, revealed subtle evidence of neurovestibular alterations that lasted a week or more following the 10-day orbital exposure.
Fifty patients each of Q-wave myocardial infarction (QMI) and non-Q-wave myocardial infarction (NQMI) were studied clinically and followed up for one year. Significant differences were observed between the two groups concerning the mean age (higher in NQMI, p < 0.05), sex (more females in NQMI, p < 0.01), location of the infarct (inferior in QMI and anterolateral in NQMI, p < 0.01), past ischaemic episodes (higher in NQMI, p < 0.001), post infarction ischaemic episodes (higher in NQMI, p < 0.05), early mechanical and electrical complications (higher in QMI, p < 0.05), peak serum enzyme levels (higher in QMI, p < 0.05) and both early mortality (higher in QMI, p < 0.05) and subsequent mortality rates (higher in NQMI, p < 0.05). The total one year mortality was similar in both the groups (30%). When only anterolateral infarctions were considered longterm prognosis for QMI patients was worse than that of NQMI patients (65% vs 37.5%, p < 0.05). Contrariwise, irrespective of the type of infarction, QMI or NQMI, anterolateral infarction resulted in higher mortality than inferior wall infarction (46.7% vs 5% p < 0.001).