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Biomedical subjects

K K Mohan

Publications and source records attributed to K K Mohan.

10 recordsLinked to original sources
PubMed1999

Positron emission tomography in pediatric neurology.

Positron emission tomography (PET) is an accurate and relatively noninvasive way of studying brain activity using systemically administered tracers labeled with positron emitting isotopes. In pediatric neurology, it has great scope not only to elucidate the complexities of the developing brain but also to understand disease processes and characterize biological risk factors. Its greatest clinical utility lies in the field of epilepsy where it is used (in patients with intractable partial epilepsy) to localize epileptogenic foci for surgical resection. In addition, functional brain mapping using PET is increasingly being used to reliably and accurately identify speech and sensory-motor areas to minimize postoperative morbidity. PET is also useful in evaluating neurodegenerative disorders and cognitive abnormalities when magnetic resonance imaging scans are unrevealing. The technology continues to progress rapidly through improvements in imaging and radiopharmacology with potential applications in neurooncology, cerebral vascular disease, and metabolic diseases.

Brain↗
PubMed1996

Diagnostic utility of video EEG monitoring in paroxysmal events.

OBJECTIVES: A retrospective study was conducted to evaluate clinical usefulness of video EEG monitoring in patients with suspected epileptic seizures. MATERIAL AND METHODS: A total of 444 patients who had diagnostic video EEG from January 1989 to December 1992 were studied after excluding those with known medically refractory focal epilepsy undergoing presurgical evaluation. Most were outpatients and had video EEG monitoring during normal working hours over 1-5 days. RESULTS: The procedure had a success rate of 73%; characteristic events were captured and categorized in 53% of the patients. Patients with an event frequency of at least one per week or those who had events characterized by motor manifestations showed a higher yield. Thirty-two percent of the patients had psychogenic seizures. Thirty-four percent of the patients had either epileptic seizures recorded during the study or showed clear-cut interictal epileptiform abnormalities providing strong evidence of underlying epileptic process. CONCLUSION: In patients with frequent paroxysmal events, a video EEG study provides diagnostically critical information. It can be performed usually as an outpatient investigation.

Adult↗
PubMed1994

Diagnostic criteria for tuberculous meningitis and their validation.

SETTING: Tuberculous meningitis (TBM) has high morbidity and mortality. Demonstration of tubercle bacilli in cerebrospinal fluid (CSF), the only reliable method of diagnosis, is time consuming and has a low yield. Early diagnosis and treatment are of utmost importance for favourable outcome. OBJECTIVE: The study was conceived to define easy to use criteria. METHODS: A set of criteria using clinical features, CSF examination and computed tomography (CT) findings were defined. 76 patients suspected of having TBM were divided into definite, highly probable, probable and possible TBM based on the criteria. The validity of criteria was tested using information from bacterial isolation, polymerase chain reaction (PCR) test for tuberculosis, response to treatment and autopsy. RESULTS: PCR was positive in over 75% of patients in the highly probable and probable groups. 91% of patients with highly probable and 66% with probable TBM improved on antituberculosis therapy. CONCLUSION: The criteria are reliable in making early diagnosis of TBM.

Adult↗
PubMed1993

Hemiplegia in posterior cerebral artery strokes.

Hemiplegia is an unusual presenting feature of posterior circulation strokes. We report five cases who presented with hemiplegia and in whom CT scans revealed evidence of infarcts in posterior cerebral artery territory.

Adult↗
PubMed1991

Rapid diagnosis of tuberculous meningitis by polymerase chain reaction.

The polymerase chain reaction (PCR) in cerebrospinal fluid was compared with conventional bacteriology and an enzyme-linked immunosorbent assay (ELISA) for cerebrospinal fluid antibodies in the diagnosis of tuberculous meningitis (TBM). PCR was the most sensitive technique; it detected 15 (75%) of 20 cases of highly probable TBM (based on clinical features), 4 (57%) of 7 probable cases, and 3 (43%) of 7 possible cases. ELISA detected 11 (55%) of the highly probable cases and 2 each of the probable and possible cases. Culture was positive in only 4 of the highly probable cases. Among the controls (14 pyogenic meningitis, 3 aseptic meningitis, 34 other neurological disorders), 6 subjects tested early in the study (2 pyogenic meningitis, 4 other disorders) were PCR positive. Second DNA preparations from their stored cerebrospinal fluid samples were all PCR negative, suggesting that the false-positive results were due to cross-contamination. 18 PCR-positive TBM samples retested were all still PCR positive. The antibody ELISA was positive in 3 controls despite the use of a high cutoff value.

Bacteriological Techniques↗
PubMed1982

Analgesics and asthma.

Aspirin and many other analgesics may be hazardous for some patients with asthma. These patients, numbering approximately 10% to 15% of all asthmatics, have a clinical course that has been well characterized. The diagnosis is usually made from the history, but sometimes it requires analgesic challenge tests. The pathogenesis remains controversial. It appears that the analgesics responsible for the syndrome inhibit prostaglandin synthesis, and this action in turn causes the release of potent bronchoconstrictors such as SRS-A, histamine, or kinins. Usually, recognition of the syndrome and careful avoidance of prostaglandin synthesis inhibitors in affected patients are the two steps needed for effective management. Persistent symptoms, however, may require aminophylline, corticosteroids, and disodium cromoglycate as well. Recent developments may allow these patients to use substituted aspirin analogues or even aspirin itself under certain conditions. Further investigation of the prostaglandins may promote a better understanding of asthma.

Alprostadil↗
PubMedDate not supplied

Computed tomography--a reliable diagnostic modality in pulmonary asbestosis.

Forty-six individuals with documented asbestos exposure were studied by computed tomography as part of their initial evaluation. CT sections were compared to standard chest radiographs and pulmonary function tests. The results showed computed tomography to be able to detect early signs of asbestosis in patients with inconclusive conventional radiographs or intact pulmonary function tests, the same as to demonstrate extensive pulmonary pathology in long-standing cases.

Adult↗
PubMedDate not supplied

Conceptual design of a cellular filter to remove trace viral contaminants in blood.

Various process alternatives and designs of using a filter containing cellular adsorbents to remove trace viral contaminants from blood and other protein solutions have been studied. Sterilization charts have been developed that can be used to estimate the filter size required to achieve a desired sterilization criterion. A parametric study was carried out to identify various process parameters that may affect this physical trace removal process. It has been demonstrated that the adsorption rate constant is a critical parameter in the design of an efficient cellular filter for viral contaminant removal. This constant is characteristic of the virus-cell system under consideration and is shown to be particularly sensitive to the cell surface receptor density, adsorbent diameter, and fluid flow rate. Higher log titer reduction in virus concentrations can be achieved with low flow rates and no recycle. Preliminary analyses indicate the feasibility of using a magnetically stabilized fluidized filter (MSFF) reactor design for effective virus removal from these complex solutions.

Adsorption↗