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Biomedical subjects

A Kohli

Publications and source records attributed to A Kohli.

At least 37 records · Page 2Linked to original sources
PubMed1997

MRI of the brain in patients with miliary pulmonary tuberculosis without symptoms or signs of central nervous system involvement.

MRI was performed on patients with miliary pulmonary tuberculosis to look for brain involvement and to study the features sequentially, during treatment. We studied seven patients with typical radiographic tuberculosis, and no symptoms or signs of central nervous system involvement. Conventional spin-echo (SE) imaging, including contrast enhanced images, was performed in all cases. All patients showed brain involvement: four patients showed lesions mainly less than 3 mm in diameter, better seen on contrast-enhanced images. These patients showed oedema around the lesions after 2 months of treatment, with subsequent regression on follow-up. The remaining three patients had multiple lesions, 3 mm or more in diameter, which showed a gradual decrease on follow-up. We conclude that the brain may commonly be involved in miliary pulmonary tuberculosis. The response to treatment depends on the stage of the granuloma and shows a definite pattern of healing on follow-up.

Adolescent↗
PubMed1997

Anterior cerebral artery territory infarction in neurocysticercosis: evaluation by MR angiography and in vivo proton MR spectroscopy.

Vascular complications of neurocysticercosis are common, but frequently not recognized. Mostly these are in the form of an endarteritis involving the smaller basal vessels due to basal exudates. Large vessel territory infarction has been clearly documented in not more than 10 cases. All these cases had either a chronic meningeal state or close proximity of cysts to the vessel wall explaining the vasculitis. We report a case that developed anterior as well as segmental middle cerebral artery territory infarction in the acute encephalitic state of neurocysticercosis. MR angiography showed constriction in the proximal segment of the right anterior cerebral artery. There was no biochemical or imaging evidence of a meningeal reaction. In vivo MR spectroscopy over the infarction showed absent N-acetyl-aspartate, low creatine and high lactate. This is the first case showing a large vessel territory infarction in the encephalitic state of neurocysticercosis, with no meningeal reaction. Focal arteritis due to an adjacent brain parenchymal reaction could be a possible mechanism for the vasculitis. MR spectroscopy may have a potential role in assessing tissue viability and therapeutic modalities in such infective vasculitis.

Albendazole↗
PubMed1997

Laminin and cathepsin B as prognostic factors in stage I non-small cell lung cancer: are they useful?

Laminin, a glycoprotein component of basement membrane, and cathepsin B, a lysosome-derived proteinase, are thought to play a role in the complex process of tumor invasion and metastasis. This study evaluates the possible prognostic significance of laminin degradation and cathepsin B expression in Stage I (T1NO, T2NO) human non-small cell lung cancer. Archival, formalin-fixed, paraffin-embedded lung tissue from patients with documented Stage I non-small cell cancer was studied in a series of 31 patients (14 men, 17 women; ages 40-82 yr; mean age, 67 yr) by using polyclonal antibodies against laminin and cathepsin B. The immunoexpression of laminin was assessed with respect to a continuous versus discontinuous pattern, whereas that of cathepsin B was semiquantitated according to a four-tiered grading scale: 0, 0% positive cells; 1, 1 to 9%; 2, 10 to 49%; and 3, more than 50% positive cells. Cox proportional hazards models and Kaplan-Meler survival analysis were used to evaluate the association of possible risk factors, including laminin and cathepsin B, with survival. Univariate analysis looking at possible associations of survival with age, sex, histologic type, degree of tumor differentiation, and tumoral stage (T1NO, T2NO) did not show significant association. Likewise, degradation of laminin and immunoexpression of cathepsin B did not show significant association with survival. Although previous studies suggested improved survival with increased laminin expression and decreased survival with high expression of cathepsin B, the results applying to intrastage (Stage I) non-small cell cancer suggest that the expression of laminin and cathepsin B has little prognostic significance.

Adult↗
PubMed1996

Accidental strangulation in a rickshaw.

A 40-year-old female was accidentally strangulated by a 'Chunni' (piece of cloth worn around neck) while travelling in a cycle rickshaw. She was declared dead on arrival in the hospital. This case highlights the hazards of wearing cloth loosely around the neck while travelling in a rickshaw which is a common mode of transport for short distances in India and other South-East Asian countries.

Accidents↗
PubMed1996

Human immunodeficiency virus type 1 drug susceptibility during zidovudine (AZT) monotherapy compared with AZT plus 2',3'-dideoxyinosine or AZT plus 2',3'-dideoxycytidine combination therapy. The protocol 34,225-02 Collaborative Group.

Human immunodeficiency virus type 1 (HIV-1) isolates obtained prior to and during a combination therapy trial comparing zidovudine (AZT; 3'-azidothymidine) monotherapy with AZT plus 2',3'-dideoxyinosine (ddI) or AZT plus 2',3'-dideoxycytidine (ddC) were assessed for the development of drug resistance. Drug susceptibility was measured by using two different phenotypic assays, one that requires infection of peripheral blood mononuclear cells with HIV-1 isolated from cocultures and a second based on infection of HeLa CD4+ cells with recombinant virus containing the reverse transcriptase (RT) of the clinical isolate. In addition, genotypic assessment of resistance was obtained by DNA sequencing of the RT coding region. No difference in the development of AZT resistance was noted in isolates from individuals receiving AZT monotherapy or combination therapy. However, a low frequency of ddI or ddC resistance was seen in isolates from the combination arms, which may at least partially explain the enhanced efficacy observed with these drug combinations compared with monotherapy. It was noted from DNA sequencing that a relatively high frequency of the nonnucleoside RT inhibitor resistance mutation, codon 181 changed from encoding Tyr to encoding Cys, was present in some isolates both before and during nucleoside analog combination therapy. Since these patients were unlikely to have access to nonnucleoside RT inhibitors, it is probable that this mutation preexisted at a reasonable level in the wild-type virus population. Comparisons of the AZT susceptibility assays indicated a good correlation between the phenotypic and genotypic determinations. However, direct numerical comparisons between the phenotypic assays were not reliable, suggesting that valid comparisons of different resistance data sets will require the use of the same assay procedure.

Antigens, CD↗
PubMed1996

Significance of amino acid variation at human immunodeficiency virus type 1 reverse transcriptase residue 210 for zidovudine susceptibility.

Amino acid variation at reverse transcriptase (RT) codon 210 (generally Leu-210 to Trp [L210W], TTG-->TGG) is occasionally detected after the initiation of azidothymidine (AZT) therapy. The impact of this variation on AZT resistance and viral replication was addressed by four different approaches. The frequency and genetic background of the L210W mutation in vivo were assessed by analyzing sera of AZT-naive and AZT-experienced patients by RT-PCR and DNA sequencing. The degree of AZT resistance (50% infective concentration [IC50]) of recombinant viruses constructed by using the RT of 21 clinical isolates was stratified by the presence or absence of the 210 mutation. The AZT IC50S of a panel of mutant viruses (with or without W-210) constructed by site-directed mutagenesis in an HXB2 background were assayed by using a HeLa CD4 plaque reduction assay. Finally, the effect of the 210 mutation on viral replication was assessed by replication competition of an AZT-resistant virus, RTMN (L-41/Y-215), and RTMN with the W-210 mutation in the presence and in the absence of AZT. In AZT-naive patients, tryptophan at RT residue 210 was rare. After AZT exposure, W-210 appeared in a minority of those patients, most commonly in association with L-41 and Y-215. The presence of W-210 increased the AZTIC50 by two- to fourfold, as determined by both the recombinant virus assay and site-directed mutagenesis. A significant replication advantage in favor of the wild-type L-210 over W-210 was observed, although the selection against the 210 mutant was two- to threefold lower when the viruses were grown in the presence of 5 microM AZT. In summary, the L210W mutation appears to be of marginal significance, conferring approximately two- to fourfold-reduced sensitivity to AZT compared with similar AZT-resistant genomes with L-210. The selection pressure against W-210 may account for the modest proportion of patients in which W-210 appears in vivo.

Antiviral Agents↗
PubMed1995

In vivo proton magnetic resonance spectroscopy in a case of intracranial hydatid cyst.

We performed in vivo proton magnetic resonance spectroscopy (MRS) in a patient who had an intracranial hydatid cyst. Besides lactate, alanine, and acetate, a large resonance for pyruvate was observed. These findings were further confirmed by ex vivo high-resolution NMR spectroscopy of the evacuated cyst fluid, as well as of the fluid aspirated from a cyst in the liver of the same patient. The MRS pattern appeared different from that seen in other cystic lesions of the CNS. In vivo MRS may be used as an adjunct to imaging in the diagnosis of intracranial hydatid cysts. It may also have a role in monitoring drug therapy.

Brain Diseases↗
PubMed1995

In vivo localized proton magnetic resonance spectroscopy of intracranial tuberculomas.

In vivo proton magnetic resonance spectroscopy (MRS) was performed in ten patients with intracranial tuberculomas with the aim of finding biochemical finger prints which may help in the noninvasive diagnosis of the disease. Diagnosis of tuberculoma was confirmed in all these cases retrospectively. Ex vivo spectroscopy of formalin fixed samples of four granulomas and a normal brain (cerebellar) tissue, was performed to confirm the in vivo resonances. The in vivo study showed resonance at 1.3 ppm and 0.9 ppm assigned to methylene group (CH2)n and terminal methyl groups (-CH3) of fatty acids respectively which was subsequently confirmed by the ex vivo study. Large resonances of fatty acids in in vivo study appeared to be due to high lipid content of caseous material. It is concluded that in vivo proton spectroscopy may be helpful in differentiating tuberculomas from other intracranial mass lesions which have diagnostic difficulties on MR imaging.

Adult↗
PubMed1994

MR imaging and angiography in tuberculous meningitis.

MRI was performed on 26 patients with tuberculous meningitis, with particular reference to document the cranial nerve abnormalities. MR angiography (MRA) was performed in 20 of the patients. Meningeal enhancement in the basal cisterns or over the convexity of brain was seen in all patients; two show ependymal enhancement. Tuberculomas, single (3), multiple (12) or miliary (2) were detected in 17 patients. Of the 9 patients with cranial nerve palsies, 7 showed contrast enhancement with or without thickening of the involved nerve. Abnormality signal intensity of the involved nerve was seen on proton density and T2-weighted images in one of these patients. MRA revealed focal arterial narrowing in 10 patients, the vessels commonly affected being the terminal segment of the internal carotid artery and the proximal segments of the middle and anterior cerebral arteries. One patient also had a small aneurysm of the proximal middle cerebral artery. Infarcts, haemorrhagic (8) or bland (6), were detected in 14 patients; most were the basal ganglia and internal capsules, large middle or anterior cerebral arterial territory infarcts being seen in only two cases.

Adolescent↗
PubMed1994

MRI in intraspinal tuberculosis.

We studied 20 patients with intraspinal tuberculosis (TB), to characterise the MRI features of tuberculous meningitis and myelitis. MRI leptomeningitis and intramedullary involvement in 11 patients, intramedullary lesions alone in 5, leptomeningitis alone in 2, and isolated extradural disease in 2. TB leptomeningitis was characterised by loculation of the cerebrospinal fluid (CSF), nerve root thickening and clumping (seen only in the lumbar region) or complete obliteration of the subarachnoid space on unenhanced images. Gd-DTPA-enhanced images proved useful in 6 cases, revealing linear enhancement of the surface of the spinal cord and nerve roots or plaque-like enhancement of the dura-arachnoid mater complex. Intramedullary lesions included tuberculomas (8), cord oedema (5) and cavitation (3). In seven cases of intramedullary tuberculoma multiple lesions with skip areas were seen, without significant cord swelling. One patient had an isolated lesion in the conus medullaris. The lesions were iso- or hypointense on T1-weighted images, iso-, hypo- or hyperintense on T2-weighted images and showed rim or nodular enhancement with contrast medium.

Adolescent↗
PubMed1994

Tuberculous radiculomyelitis (arachnoiditis): myelographic (and CT myelographic) appearances.

Tuberculous radiculomyelitis (arachnoiditis) remains one of the important causes of paraplegia in India. The diagnosis usually rests on clinical history and examination, and on laboratory findings in the cerebro-spinal fluid (CSF). Few descriptive reports are available of the myelographic appearance, with water-soluble contrast media, in tuberculous radioculomyelitis (arachnoiditis). A retrospective review of 21 myelograms and 10 computed tomographic (CT) myelograms, in 14 patients with tuberculous radiculomyelitis, was carried out, with a view to describing, in detail, the radiographic features. An attempt was made to assess the use of the radiologic procedures in diagnosis and follow up in these patients. Conventional myelographic findings included block (8/14), irregular subarachnoid space (9/14), filling defects (8/14), sluggish contrast flow (2/14), root thickening (3/14) and atrophic cord (2/14). Computed tomographic myelography showed reduced contrast density in portions of the opacified CSF ring around the cord in affected region (6/7) and, in addition, demonstrated septa and adhesions. Intravenous contrast CT was not found to be useful (2/2). Follow-up studies showed partial resolution (3/6), deterioration (1/6) and status quo of radiological findings (2/6). Although these changes can be seen in chronic radiculomyelitis (arachnoiditis) from other causes, such as leukaemic infiltration/lymphoma, other chronic central nervous system infections and iatrogenic causes, including repeated intrathecal injections, conventional myelography appeared to be useful for diagnosis and follow up in tuberculous radiculomyelitis (arachnoiditis).

Adult↗
PubMed1994

Secondary involvement of femur in carcinoma of gall bladder.

A case with bony metastasis to right femur from a primary carcinoma of gall bladder is described. This is probably one of the most rare presentation of the disease without producing any signs or symptoms suggestive of a primary pathology in gall bladder.

Adenocarcinoma↗
PubMed1993

Quantitative detection of HIV-1 drug resistance mutations by automated DNA sequencing.

A comparison has been made between manual and automated DNA sequencing procedures to evaluate the ability to distinguish mixtures of wild-type and mutant sequences. Quantitative detection of such mixtures of HIV-1 drug resistance mutations was best achieved using an automated system that uses fluorescent-labelled sequencing primers. This procedure has a wide range of applications in clinical research, including heterozygote analysis. Software that automatically reports mixed-base positions is presented.

Automation↗