Biomedical subjects
T Cherian
Publications and source records attributed to T Cherian.
The paroxysmal cough in pertussis can be extremely distressing.
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Acute respiratory infections in developing countries: current status and future directions.
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Non-O:1 Vibrio cholerae bacteremia and peritonitis in a patient with nephrotic syndrome.
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Melioidosis In India: the tip of the iceberg?
Diagnosis of melioidosis by the isolation of Burkholderia pseudomallei from one or more body fluid/tissue specimens of 6 Indian subjects, 5 of whom had not travelled outside India, is reported. The places of residence of these 6 and one patient previously reported, namely Tripura (2), Kerala (2), Orissa (1), Tamil Nadu (1) and Maharashtra (1) are therefore potentially endemic for melioidosis. B.pseudomallei closely resembles common contaminant Pseudomonas sp. and are easily mis-identified in microbiology laboratories. We surmise that melioidosis is underdiagnosed and underreported in India and we alert clinicians, microbiologists and public health professionals to the possibility of melioidosis being far more common than previously recognised.
Disseminated melioidosis.
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Plague in India.
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The Part II examination: effect on IMGs.
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A cluster of invasive pneumococcal disease in young children in child care.
OBJECTIVE: To investigate a cluster of invasive pneumococcal disease in children 8 to 26 months of age, using standard microbiological procedures and ribosomal DNA gene-restriction patterns to characterize the outbreak strain. DESIGN: Outbreak investigation. SETTING: A family child-care home with six children in Baltimore, Md. RESULTS: During an 8-day period, three of the six children in the family child-care home had febrile illnesses with pneumococcal bacteremia, and a fourth had purulent pneumococcal conjunctivitis. Type 12F Streptococcus pneumoniae was isolated from the four ill children and from the nasopharynges of the two healthy children. Ribotyping revealed all outbreak isolates had an identical ribotype pattern. Administration of rifampin to the children did not eradicate carriage of the organism. CONCLUSIONS: Our data demonstrate that child care provides an opportunity for outbreak of invasive pneumococcal disease in young children. This observation suggests a need for increased alertness for clusters of pneumococcal disease in young children in child-care facilities and underscores the necessity for a pneumococcal vaccine that is effective in infants and young children.
The sternomastoid island myocutaneous flap for oral cancer reconstruction.
OBJECTIVE: To evaluate the usefulness of the sternomastoid island myocutaneous flap for reconstruction of defects after excision of oral cancer. PATIENTS: One hundred eleven superiorly based sternomastoid island myocutaneous flaps were used for one-stage primary reconstruction in 110 consecutive patients with oral cancer during a 53-month period from June 1985 to November 1989. RESULTS: Ninety-eight patients had radiation therapy before surgery. One hundred six flaps were used for mucosal lining of the mouth and six flaps were used for providing skin cover. Flap-related complication developed in 38 patients (34.5%). Total flap loss occurred in eight patients (7.3%). Radical irradiation before surgery significantly increased flap-related complications. Low-molecular-weight dextran did not improve flap survival. After a minimum follow-up of 24 months, nine patients (8.2%) had recurrences in the ipsilateral neck. The flap could easily reach the oral cavity without producing tension on the suture line. The flap also did not produce excessive bulk in the mouth or on the face. CONCLUSION: In a selected group of patients with a clinically N0 neck, the sternomastoid island myocutaneous flap is oncologically safe and it gives satisfactory cosmetic and functional results with no lasting morbidity.
The role of extracellular calcium in pregnancy-induced attenuation of phenylephrine contraction in rat aorta with functional endothelium.
The effect of pregnancy on the supply of calcium ions for the contractile responses of rat aortic rings to phenylephrine was investigated. The contractility of intact aortic rings from pregnant rats, compared with that of similar rings from non-pregnant rats, to phenylephrine and potassium chloride was significantly decreased. Contractions of rings from non-pregnant rats, pretreated with phenylephrine or potassium chloride, in response to calcium chloride were greater than those of similarly treated rings from pregnant rats. When the concentration of calcium chloride in the medium bathing the rings was reduced to 0.8 mmol.l-1, the contractile response to phenylephrine was significantly (P < 0.005) inhibited in rings from both pregnant and non-pregnant rats but to a greater extent in rings from non-pregnant rats. Contractions of aortic rings from pregnant rats in response to phenylephrine in calcium-free medium were similar to those of rings from non-pregnant rats, suggesting equal dependence on calcium from intracellular stores. The results suggest that pregnancy decreased the response to calcium influx into the aortic smooth muscle cells through both receptor- and voltage-operated calcium entry pathways. Since de-endothelialization reversed the pregnancy-induced diminished contraction to phenylephrine, it is likely that pregnancy interfered with contractions induced by activation of receptors with phenylephrine through enhanced production of endothelium-derived relaxing factor(s).
Use of PCR-enzyme immunoassay for identification of influenza A virus matrix RNA in clinical samples negative for cultivable virus.
Influenza A virus infections are a major cause of morbidity and mortality worldwide. Standard diagnostic methods either are not efficient in identifying infected individuals in a timely manner or lack sensitivity. We developed a PCR-enzyme immunoassay (PCR-EIA) for the detection of influenza A virus RNA in respiratory secretions. A reverse transcription PCR was performed with oligonucleotide primers directed at a highly conserved area of the influenza A matrix gene. Amplified DNA was identified by hybridization in solution to a nested biotinylated RNA probe and quantitated in an EIA. PCR-EIA detected small quantities of RNA from the three prevalent subtypes of human influenza A virus. Influenza B and C, parainfluenza, measles, mumps, and respiratory syncytial viruses tested negative. The potential efficiency of PCR-EIA for use in clinical diagnosis was determined by testing 90 nasal wash specimens obtained daily over a 10-day period from nine human volunteers infected with influenza A virus. Thirty-seven of the postinfection samples had detectable influenza A virus RNA by PCR-EIA, whereas only 26 postinfection samples were positive by culture. PCR-EIA was particularly efficient for the identification of influenza A virus in samples obtained more than 4 days after infection. Seventeen of 45 such samples were positive, whereas virus was cultivated from 4 samples (P < 0.00005). All preinfection samples from volunteers subsequently infected with influenza A virus were negative by PCR-EIA, as were samples from a volunteer infected with parainfluenza virus type 3. Nucleic acid amplification techniques represent important tools for the timely and sensitive diagnosis of influenza A virus infections and, therefore, their management and control.
Immune response to measles, mumps & rubella vaccine at 9, 12 & 15 months of age.
Seroconversion rates to measles, mumps and rubella (MMR) in children given MMR vaccine at 9, 12 and 15 months of age were assessed so as to recommend the optimum age for vaccination. A total of 164 infants were recruited, of whom 123 completed the study. Sera were tested pre-immunization and 4 wk after MMR vaccine, for the presence and titres of antibodies by the haemagglutination inhibition (HI) test and by enzyme-linked immunosorbant assay (ELISA). The pre-immunization results showed that levels of maternal antibody detectable by HI had disappeared by 9 months in all infants in the case of measles, but not in the case of mumps or rubella. Evidence for subclinical infection with the three viruses was found in 19 to 31 per cent of infants by 15 months of age. The responses to measles antigen by both HI test and ELISA were better (> 95%) at 12 or 15 months than at 9 months (80%). Vaccine failure was low at 12 or 15 months. The response to mumps antigen by HI antigen was also higher (92%) at 12 months than at 9 months (75%). Vaccine failure was less frequent at 12 months than at 9 months. The ELISA was found to be unreliable for mumps virus antibody testing. Rubella vaccine evoked good seroresponse (> 92%) at 9, 12 and 15 months, both by HI test and ELISA. Thus a better response to the MMR vaccine was obtained at or after 12 months of age than earlier. Hence, a dose of MMR may be given optimally at 12 months for children not previously immunized with measles vaccine. For those already given measles vaccine, the MMR may be given at 12 or 15 months.
An epidemic of dengue haemorrhagic fever & dengue shock syndrome in & around Vellore.
This report describes an epidemic of dengue haemorrhagic fever/dengue shock syndrome (DHF/DSS) in the North Arcot Ambedkar district and the adjoining districts in Tamil Nadu and Andhra Pradesh. Nineteen children who fulfilled the clinical criteria for the diagnosis of DHF/DSS were admitted to the Christian Medical College Hospital, Vellore, during June through November, 1990. The clinical presentation was similar to that described in South-east Asian children and the case fatality rate was 26.3 per cent. Serology was confirmatory or suggestive of recent dengue virus infection in 16 children, uninterpretable in 2 and not consistent with recent dengue virus infection in 1 child. All children over 1 yr of age had very high antibody titres suggesting a secondary response whereas infants had lower titres consistent with primary response. The occurrence of recurrent epidemics in this region in the last few years with associated high case fatality emphasizes the urgent need for public health measures to curtail further epidemics.
Overall survival from breast cancer in Kerala, India, in relation to menstrual, reproductive, and clinical factors.
BACKGROUND: Breast cancer accounts for one-fourth of cancer cases seen in female patients in Kerala, India. Results of a retrospective analysis of breast cancer in Kerala are presented in this article. METHODS: Case records of 449 patients with breast carcinoma treated during 1983-1984 were reviewed. Survival analysis was done by the Kaplan-Meier product limit method. The survival curves were compared by the log-rank test. A forward stepwise procedure with the Cox proportional hazards regression analysis was performed to identify factors influencing survival. RESULTS: The overall 5-year survival rate was 40%. The 5-year survival rates were 85% for patients with T1, 63% for T2, 32% for T3, and 21% for T4 lesions. Those with N0 disease had a 68% 5-year survival rate. The survival rates were 90% for patients with Stage I, 65% for Stage II, 33% for Stage III, and 6% for Stage IV disease. On multivariate analysis, the following factors were found to significantly influence survival: response to treatment (P < 0.001), stage (P < 0.01), and regional nodal involvement (P < 0.05). CONCLUSIONS: Two-thirds of patients with advanced-stage disease on presentation seem to account for the poor overall survival. Early detection of breast cancer by breast self-examination and physician breast examination should be encouraged in developing countries to improve treatment results in breast cancer.
Effect of pregnancy on relaxation of rat aorta to magnesium.
OBJECTIVE: There is evidence for involvement of the endothelium in magnesium induced vasodilatation. In view of the use of magnesium in the treatment of women with pre-eclampsia, and because the mechanism of the vascular effects of magnesium in pregnancy is not fully understood, this study examined the dilator response to magnesium of aortic rings from pregnant and non-pregnant rats. The role of the endothelium was also evaluated. METHODS: Rings from descending thoracic aorta of pregnant and non-pregnant rats, contracted with either 10(-7) M phenylephrine or 40 mM potassium chloride, were relaxed with increasing concentrations of MgSO4 in the presence or absence of 10(-6) M indomethacin or endothelium. The rings were also contracted to 10(-5) M phenylephrine, in calcium-free medium containing 0, 1.2, or 4.8 mM MgSO4. RESULTS: The relaxation of aortic rings from pregnant rats to MgSO4 was greater when stimulated with potassium chloride but that of rings from non-pregnant rats was greater when stimulated with phenylephrine. Neither the presence of MgSO4 nor pregnancy had any effect on intracellular calcium dependent contraction. The relaxations of rings from either pregnant or non-pregnant rats to MgSO4 were not significantly altered by de-endothelialisation or pretreatment with 10(-6) M indomethacin. CONCLUSIONS: The effect of pregnancy on magnesium induced relaxation of rat aortic smooth muscle was dependent on the agent used to induce contraction in the tissue, probably because pregnancy exerted different actions on receptor and voltage operated calcium channels. This effect of pregnancy was independent of either endothelial function or prostaglandin synthesis. Neither pregnancy nor the presence of magnesium affected the release of intracellular stored calcium.
Plasma from normal pregnant women alters the reactivity of rabbit aortic smooth muscle with functional endothelium.
1. The effects of normal human pregnant plasma on the reactivity of rabbit aortic rings with documented endothelium have been studied. The rings were incubated in plasma from either normal pregnant or non-pregnant women and the effects of incubation on their responses to noradrenaline (NA), calcium chloride stimulation and potassium chloride-induced relaxation were examined. 2. There was no significant difference in the responses to NA in rings incubated in plasma from either pregnant or non-pregnant women. 3. The responses of the rings, incubated in both types of plasma, to calcium chloride stimulation through receptor-operated channels were similar, but rings incubated in plasma from pregnant women demonstrated decreased sensitivity and contractility to calcium chloride stimulation through voltage operated channels. 4. Potassium chloride-induced relaxation was significantly enhanced in rings incubated in plasma from normal pregnant women. The pattern of the responses was unaltered by either de-endothelialization or pretreatment of the rings with indomethacin. 5. The effects of plasma from pregnant women are similar to what has been reported as characteristic of vascular smooth muscle in normal pregnancy.
Mechanism of pregnancy-induced attenuation of contraction to phenylephrine in rat aorta.
The role of endothelium in the decreased contraction to phenylephrine in aorta of pregnant Wistar rats has been studied. Contractions in response to phenylephrine were significantly decreased in aortic rings from pregnant rats compared to those from non-pregnant rats. Pretreatment of the rings with indomethacin did not significantly alter the pattern of responses. When endothelium was removed from the rings, contractions of rings from non-pregnant rats were similar to those from pregnant rats. Acetylcholine-induced relaxations of rings from pregnant and non-pregnant rats precontracted with phenylephrine were not significantly different. The results suggest that in the rat aorta and under in vitro conditions, pregnancy-induced attenuation of contraction to phenylephrine is, at least partly, endothelium dependent and that the release of the endothelium factor responsible for this alteration in response may be indomethacin insensitive.