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S K Malhotra

Publications and source records attributed to S K Malhotra.

At least 19 recordsLinked to original sources
PubMed2002

Auditory function following spinal analgesia. Comparison of two spinal needles.

BACKGROUND AND OBJECTIVE: Auditory impairment is among the lesser known complications of spinal analgesia. The aim of the present study was to determine the degree of vestibulocochlear dysfunction in patients undergoing spinal analgesia for lower abdominal surgery. METHODS: Eighty patients who had received spinal analgesia for lower abdominal surgery were studied. Males were undergoing inguinal herniorraphy and the females tubectomy. Audiograms were performed before operation and on the second and seventh postoperative days. Hearing levels were measured from 250 Hz-8 kHz. In Group 1 (n = 40) a 22-gauge, cutting type of spinal needle (Howard Jones) was used. In Group 2 (n = 40) a 25-gauge, non-cutting spinal needle (Whitacre) was used. RESULTS: Hearing loss >10 dB was noticed in three patients in Group 1 and none in Group 2. The mean hearing level was more reduced in Group 1 patients. CONCLUSIONS: Use of cutting type spinal needle is associated with a greater decrease in mean hearing levels compared to the non-cutting type.

Abdomen↗
PubMed2001

Monitoring of irrigation fluid absorption during percutaneous nephrolithotripsy: the use of 1% ethanol as a marker.

This study was performed in 32 ASA I patients undergoing percutaneous nephrolithotripsy under general anaesthesia, using absorption of 1% ethanol as a marker to monitor irrigation fluid absorption. Various parameters of fluid absorption were studied and compared, including irrigation fluid volume, irrigation time, total volume of irrigation fluid absorbed and the rate of irrigation. The amount of irrigant used vs. the volume absorbed and the volume absorbed vs. total irrigation time were observed. Fluid absorption occurred in 78% of patients, and 28% absorbed volumes in excess of 1 l. The mean volume of fluid absorbed was 696.7 ml. The maximum fluid absorption was observed when the irrigation fluid volume, total irrigation time and irrigation rate exceeded 10 l, 30 min and 200 ml.min(-1), respectively. In conclusion, this study has shown 1% ethanol to be a safe, simple and cost-effective marker of fluid absorption during percutaneous nephrolithotripsy associated with minimal adverse effects.

Adult↗
PubMed2000

Effect of pre-emptive analgesia on self-reported and biological measures of pain after tonsillectomy.

This prospective, double-blind, randomized study assessed effect of pre-emptive peritonsillar block in 30 ASA-I children, aged 6-12 years, of both sexes, scheduled for tonsillectomy. Patients were divided into three groups: those in group I received a sham block, whereas peritonsillar blocks with bupivacaine 0.25% were given to the children before tonsillectomy (group II) or immediately after surgery had been completed (group III). Constant pain, pain on swallowing, blood glucose, serum epinephrine and norepinephrine concentrations were measured immediately after surgery and 4h after operation. Patients in group I experienced more pain (P< 0.05) than those in groups II and III, both in the immediate postoperative period and over the next 4 h. Patients in groups II and III experienced similar pain (P> 0.05). The pain experienced when water was swallowed was similar to that of the constant pain. The rise of serum norepinephrine concentration in group II was significantly less (P< 0.05) compared to groups I and III. We found both pre-emptive and postoperative block to be equally effective in treating postoperative pain, with pre-emptive block being more effective in preventing the rise in norepinephrine concentration.

Analgesics, Opioid↗
PubMed1997

Reactive astrocytes: cellular and molecular cues to biological function.

For several decades, the reactive gliosis that occurs after an injury to the CNS has been considered one of the major impediments to axonal regeneration. Nevertheless, recent studies have suggested that in certain conditions, reactive astrocytes may provide a permissive substratum to support axonal regrowth. The important criteria, allowing for the distinction between permissive and non-permissive gliosis, are the ultrastructural 3D organization of the scar and more importantly the recognition molecules expressed by reactive astrocytes. Reactive astrocytes express surface molecules and produce various neurotrophic factors and cytokines. The latter in turn might modulate the production of recognition molecules by reactive astrocytes, allowing them to support post-lesional axonal regrowth. Although numerous recent articles have focused on cytokines and cell adhesion molecules, scant attention has been paid to reactive astrocytes. Reactive astrocytes should be considered a key element, like neurons, of a dynamic environment, thus forming with neurons a functional unit involved in homeostasis, plasticity and neurotransmission. Attempts are in progress to identify molecular markers for reactive astrocytes.

Animals↗
PubMed1997

Up-regulation of reactive astrogliosis in the rat glioma 9L cell line by combined mechanical and chemical injuries.

The 9L rat glioma cells grown in culture, when subjected to a mechanical injury (scratch wound) and/or a chemical injury (CdCl2) manifest changes which are characteristic of an astrocyte reaction (astrogliosis) in the central nervous system. Such changes include cell hypertrophy and an increase in immunostaining for the astrocytic marker proteins, glial fibrillary acidic protein and J1-31 antigen. Mitochondria also increase in size and number, and the endoplasmic reticulum expands in area. These mechanical and chemical injuries are coordinated, and act synergistically to induce a considerably more intense astroglial reaction by 9L cells than can be elicited with either injurious agent alone, and this occurs without any interactions with microglia, neurons or oligodendroglia. The phenomenon suggests that more than one transcriptional mechanism is involved in the activation of astrocytes, and that mechanical and CdCl2-induced injuries, respectively, probably affect different receptors and second- and third-messenger pathways. There are a number of questions concerning the molecular biology of reactive astrocytes which can be addressed through the use of the 9L rat glioma cell model. This model offers certain advantages over primary cultures of astrocytes, namely a low basal level of reactivity (because the cells are not subjected to mechanical injury prior to experimentation), an absence of contaminating microglial cells, greater ease of reproducibility of results, lower costs and avoidance of the use of animals.

Animals↗
PubMed1997

Gap junctions in 9L and C6 glioma cells: correlation with growth characteristics.

The relationship between growth properties and gap junctional communication properties of two glioma cell lines, 9L and C6, was compared. Using microinjection of a gap junction permeable fluorescent dye, it was demonstrated that 9L cells were extensively dye coupled through gap junctions, whereas C6 cells had low levels of dye coupling between the cells. More gap junctions were observed between 9L cells than between C6 cells both by electron microscopy and immunofluorescent labelling with specific antibodies. Immunoblotting and immunofluorescence labelling of cellular proteins from 9L and C6 cells also showed differences in the Cx43 connexin contents of these cells, reflecting the differences in their gap junctional communication. Northern blot analyses confirmed that the level of Cx43 mRNA was higher in 9L than in C6 cells. In spite of these differences in gap junctions, the two cell lines did not differ in their growth rates in cultures. These results suggest a lack of direct correlation between gap junctional communication and cell growth regulation in these two glioma cell lines.

Animals↗
PubMed1997

Inhibition of connexin 43 synthesis by antisense RNA in rat glioma cells.

The 9L rat glioma cells communicate via gap junctions which are formed of connexin 43. The gap junctional communication was inhibited in these cells by transfecting them with an antisense Cx43 DNA construct, and its effect on their growth rate was investigated. This construct was induced by a Zn(2+)-inducible metallothionein promoter. Results showed that the induction of antisense RNA expression in rat 9L glioma cells produced the loss of gap junctions which was reflected in the loss of gap junctional communication. By inducing the antisense construct with zinc acetate, and using specific antibodies to connexin 43, the synthesis of this connexin was inhibited in the transfected cells and gap junctions were lost on the cell-cell appositions. There was no such effect on the untransfected cells. The loss of gap junctions at cell-cell appositions also correlated with the loss of Lucifer yellow fluorescent dye transfer between the cells. The effect of loss of gap junctions on the growth rate of the cells was assessed. In spite of the drastic decrease in the number of gap junctions between cells, their growth rate was only approximately 20% less than that of the transfected but non-induced cells. Therefore, gap junction communication is not negatively related to the rate of growth of these cells.

Animals↗
PubMed1995

Detrimental effects of noise on anaesthetists.

To study the detrimental effects of operating room noise, noise levels in operating rooms were first measured and the average noise level was calculated in Decibels, which was 77.32 dB(A). An audiocassette of 90 min duration was prepared recording the operating room noise. The same audiocassette was used later to expose the 20 anaesthesia residents to the operating room noise in the acoustically treated rooms of audiology department. The noise level during exposure was maintained at 77.32 dB(A). Two cognitive functions, mental efficiency and short-term memory were studied. The tests used were the Trail Making Test and Digit Symbol Test for mental efficiency and the Benton Visual Retention Test for short-term memory. The mean pre-exposure scores for the Trail Making Test, Digit Symbol Test and Benton Visual Retention Test were 22.9 +/- 1.94, 83 +/- 2.62 and 9.55 +/- 0.51 respectively. The mean during-exposure scores were 16.35 +/- 1.39, 74.05 +/- 3.46 and 5.8 +/- 0.41 respectively (P < 0.05). In conclusion, we observed that operating room noise reduced the mental efficiency and short-term memory of anaesthesia residents.

Adult↗
PubMed1995

Rat glioma cell line as a model for astrogliosis.

In this investigation 9L rat glioma cells were grown on coverslips in culture, and when subjected to mechanical trauma, they were capable of mounting an astroglial response, without interaction with neurons, as evidenced by cell hypertrophy and increased immunostaining for glial fibrillary acidic protein and J1-31 antigen. It is of particular interest that this neoplastically transformed cell line is capable of mounting an astroglial response when subjected to mechanical trauma in vitro. The advantages of this model over in vivo models of central nervous system injury include the ease of reproducibility of results, and the ability to investigate molecular mechanisms under controlled conditions.

Animals↗
PubMed1995

Auditory functions in anaesthesia residents during exposure to operating room noise.

Twenty anaesthesia residents were exposed to a pre-recorded audio cassette of operating room noise. The noise level during exposure was maintained at 77.32 +/- 1 dB (A), which was the calculated average operating room noise in our institute. Two auditory functions i.e., speech reception threshold and speech discrimination were studied before and during exposure to noise in a pre-fixed order. The right and left ears were tested separately. Speech reception threshold showed a mean increase of 23.75 +/- 6.86 dB (A) for the right ear and 26.25 +/- 6.90 dB(A) for the left ear during exposure to noise, suggesting that speech communication may be possible only by raising the voice. Speech discrimination showed a mean percentage decrease of 23.3 +/- 4.82 per cent for the right ear and 23.5 +/- 3.89 per cent for the left ear implying that there can be a steep decrease in the ability to discriminate spoken words.

Anesthesiology↗
PubMed1995

Optimal preservation of the J1-31 antigen in astroglia examined by immunogold labelling.

Several methods for the detection of immunogold labelling for the monoclonal antibody (Mab) J1-31 in astroglial cells are described. The optimal preservation of the gold labelling is achieved in sections after cryoultramicrotomy or LR white embedding. The results obtained are consistent with the previous findings that the Mab J1-31 antigen is an intermediate filament-associated protein in the astroglial cells.

Animals↗
PubMed1994

Multiple roles of intermediate filaments.

The widespread distribution, diversity of types, and highly conserved features of intermediate filaments (IFs) and the diversity of associated proteins indicate multiple roles for IFs in the nucleus and the cytoplasm of eukaryotic cells. Traditional functions include maintenance of cell shape, cell locomotion, movement and positioning of organelles and guiding cell development. Recent studies indicate some of these functions can now be expanded. Currently available information shows that IFs are important to nuclear function and cell division, to transport between the nucleus and cytoplasm, to the mechanical integrity of cells and tissues, to reorganization of the cytoplasm and chromatin in response to intercellular signals, and to embryonic and cellular differentiation.

Animals↗