Biomedical subjects
S K Mahajan
Publications and source records attributed to S K Mahajan.
Relevance of Weil-Felix test in diagnosis of scrub typhus in India.
OBJECTIVE: To study the relationship of Weil-Felix test and microimmunofluorescence test. METHODS: Sera of 21 patients with clinical diagnosis of scrub typhus were subjected to Weil-Felix and Microimmunofluorescence tests. RESULTS: On Weil-Felix test, 13 (62%) sera showed titers 1: > or = 40-320. 7 patients showed titers 1: > or = 320, 3 showed titers 1 : 160, 2 showed titers 1 : 80 and 1 patients showed titers 1 : 40, to Proteus OXK antigen. All 21 sera showed significant titers to O. tsutsugamushi on microimmunofluorescence. CONCLUSION: Weil-Felix test is not a very sensitive test in diagnosis of scrub typhus but due to of lack of availability of definitive tests in India it canbe a useful tool when used and interpreted in the correct clinical context.
Malignant colo-jejunal fistula--a rare internal fistula.
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Scrub typhus.
Scrub typhus, a dreaded disease in pre-antibiotic era, is an important military disease which caused thousands of cases in the Far East during Second World War. It is a zoonosis and is a widespread disease in Asia and Pacific Islands. Scrub typhus is an acute febrile illness which generally causes non-specific symptoms and signs. The clinical manifestations of this disease range from sub-clinical disease to organ failure to fatal disease. Deaths are attributable to late presentation, delayed diagnosis, and drug resistance. The public health importance of this disease is underestimated because of difficulties with clinical diagnosis and lack of laboratory methods in many geographical areas. Scrub typhus is known to occur all over India and physicians should be aware of this potentially serious but easily treatable disease.
Spectrum of tuberculosis in HIV-positive patients in Uttaranchal, India.
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Experimental pathogenicity evaluation of Mycoplasma canadense from bovine mastitis in vitro and in vivo laboratory models.
Mycoplasma canadense, a clinical isolate from milk of a mastitic buffalo, was experimentally tested for its pathogenic potential in hamster tracheal ring and rabbit fallopian tube explant organ cultures (in vitro) and rat and rabbit mammary gland (in vivo) models. The activity percentage reduction in M. canadense infected hamster tracheal rings was 99.1% in comparison to 16.4% in control rings. Mycoplasma canadense, also induced complete ciliostasis at 11-day post-infection in rabbit fallopian tube explants. Histopathological lesions in these infected organ cultures were loss of cilia, desquamation or denudation of epithelium, infiltration of inflammatory cells and proliferation of macrophages as well as oedema in lamina propria. At the end of the experiments, M. canadense organisms were reisolated in pure colonies from the infected but not the control organ cultures. In the rat and rabbit mammary glands, M. canadense organisms persisted upto 6-day and 7-day postinfection, respectively and caused histopathological changes suggestive of subacute to chronic mastitis during the experimental period. The results indicate that the tested M. canadense clinical isolate was virulent.
Isolation of Mycoplasma bovoculi from genitally diseased bovines and its experimental pathogenicity in pregnant guinea pigs.
Thirteen strains of M. bovoculi, 6 from frozen bull-semen (3.5% of 168), 3 from neat bull-semen (3.0% of 100), one each from heart blood and stomach contents of aborted foetus of 85 (1.18%) bovine-abortions, one each from stomach contents and pooled internal organs of 9 (11.1%) stillborn calves, were isolated. All the isolates were resistant to ampicillin and sensitive to spiramycin, vibramycin, demeclocyclin, oxytetracycline, lincomycin and tylosin. However, variation in resistance to tetracycline, erythromycin, neomycin, kanamycin and streptomycin was observed. The gross lesions like congestion of lungs, liver, kidney and spleen were noted only in stillborn calf. However, significant microscopic lesions were encountered in internal tissues of both the aborted bovine fetuses and stillborn calf. Thickened alveolar wall, congestion of blood vessels, mesenchymal cell proliferation along with infiltration of lymphocytes and macrophages were observed in lungs. The liver showed mild infiltration of lymphocytes, macrophages in hepatic triad and necrosis of hepatic cells. The kidney tissues had focal lymphocytic infiltration in the interstitium. One strain of M. bovoculi (isolate # SBC-7/84,IO) isolated from a stillborn calf was found abortigenic upon experimental inoculation in pregnant guinea pigs.
Stroke at moderate altitude.
OBJECTIVE: To know the clinical profile, presence of various risk factors for stroke at moderate altitude and to study its relationship with hypertension and polycythemia at moderate altitude. METHODS: We analyzed the data of 100 patients, consecutively admitted to a hospital situated at an moderate altitude of 2200 meters MSL of Sub-Himalayan ranges and studied the age, gender, geographical distribution, clinical features and presence of various risk factors in relation to stroke. This is not only the first study conducted in Himachal Pradesh but also first study in India to be conducted at moderate altitude (2000-3000 meters MSL). RESULTS: Males outnumbered females (66% males, 34% females) with rural predominance (73% rural, 27% urban). Cerebral infarction (69%) was more common but primary intracerebral haemorrhage (26%) was more common than found in the West. Hypertension (62%) and smoking (60%) were most common risk factors present and polycythemia was not a significant risk factor at this altitude. CONCLUSION: Incidence of stroke was found to be lower than the study conducted at low altitude. incidence of various types of stroke was similar to other Indian studies. The combination of opposite effects of decreased hypertension and increased haematocrit could not be demonstrated at this altitude and smoking was more common than in other studies and other risk factors prevalent were same as that for low altitude.
Neurocysticercosis presenting with psychosis.
Cysticercosis consists of infection with the small bladder-like larvae of the pork tapeworm Taenia solium. The life cycle of parasite is maintained between man and pig infected with cysticerci. Epilepsy is the most common presentation of neurocysticercosis; focal signs, headache, involuntary movements and global mental deterioration are other symptoms. Psychosis is a rare presentation and may be seen in up to 5% of patients. We present a 25 years old male, who had been under treatment from psychiatry OPD for psychosis for one year, developed generalized tonic-clonic seizures. CT scan of brain revealed multiple calcified and hypodense lesions with surrounding oedema. Histopathological examination of subcutaneous nodule confirmed the diagnosis of neurocysticercosis.
Expression, purification, crystallization and preliminary X-ray diffraction studies of recombinant class B non-specific acid phosphatase of Salmonella typhimurium.
The aphA gene of Salmonella enterica sv. Typhimurium strain MD6001 was cloned in the multicopy plasmid pBluescript SK(-). The recombinant AphA protein was purified to homogeneity. The protein crystallized in the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 112.4, b = 130.2, c = 139.6 A. Consistent with the self-rotation function, there are two tetramers in the asymmetric unit, indicating a solvent content of approximately 54%. The crystals are composed of biologically active AphA molecules.
Purification, crystallization and preliminary X-ray diffraction studies of recombinant class A non-specific acid phosphatase of Salmonella typhimurium.
The phoN gene of Salmonella enterica sv. Typhimurium strain MD6001 was cloned in the multicopy plasmid pBluescript SK(-). The nucleotide sequence of the cloned gene differs from the corresponding S. typhimurium LT2 sequence at 23 residues, leading to 15 amino-acid differences, but was very close to the S. typhi phoN sequence (only three nucleotide and two amino-acid differences). The recombinant PhoN protein was purified to homogeneity. Two forms of crystals were harvested from a single crystallization condition. Diffraction intensity data were collected using a laboratory X-ray source to resolution limits of 2.5 and 2.8 A for crystals belonging to space group C2 and C222(1), respectively. Based on non-crystallographic symmetry, four monomers of PhoN are expected to be present in the asymmetric unit of the C2 unit cell. Two monomers of a biologically active dimer in the asymmetric unit of the C222(1) unit cell are expected from the Matthews coefficient.
Duodenal diverticular haemorrhage in a patient taking NSAID.
We present a 55 years old male with severe anemia with history of pain abdomen for 2 weeks and malena of 10 days duration. He was taking NSAID (Diclofenac sodium). Upper GI endoscopy done twice did not reveal any abnormality. Upper gastrointestinal (UGI) barium series with small bowel follow through revealed a diverticulum on medial wall of second part of duodenum and there was evidence of ulcer in diverticulum. He underwent diverticulectomy. On follow up after 6 months patient was asymptomatic.
Pitting oedema in hypothyroidism.
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Surgical repair of intermandibular fistula with protrusion of the tongue in a buffalo.
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Cloning and characterization of an insecticidal crystal protein gene from Bacillus thuringiensis subspecies kenyae.
A sporulating culture of Bacillus thuringiensis subsp. kenyae strain HD549 is toxic to larvae of lepidopteran insect species such as Spodoptera litura, Helicoverpa armigera and Phthorimaea operculella, and a dipteran insect, Culex fatigans. A 1.9-kb DNA fragment, PCR-amplified from HD549 using cryII-gene-specific primers, was cloned and expressed in E. coli. The recombinant protein produced 92% mortality in first-instar larvae of Spodoptera litura and 86% inhibition of adult emergence in Phthorimaea operculella, but showed very low toxicity against Helicoverpa armigera, and lower mortality against third-instar larvae of dipteran insects Culex fatigans, Anopheles stephensi and Aedes aegypti. The sequence of the cloned crystal protein gene showed almost complete homology with a mosquitocidal toxin gene from Bacillus thuringiensis var. kurstaki, with only five mutations scattered in different regions. Amino acid alignment with different insecticidal crystal proteins using the MUTALIN program suggested presence of the conserved block 3 region in the sequence of this protein. A mutation in codon 409 of this gene that changes a highly conserved phenylalanine residue to serine lies in this block.
Purification and characterization of a thermophilic and acidophilic chitinase from Microbispora sp. V2.
AIM: Purification and characterization of a chitinase from Microbispora sp. V2. METHODS AND RESULTS: The chitinase from Microbispora sp. V2 was purified to homogeneity by gel filtration chromatography with 4.6% recovery. It had a molecular weight of 35 kDa and showed maximum activity towards p-nitrophenyl-beta-d-N,N'-diacetylchitobiose, indicating a chitobiosidase activity. The enzyme had a pH optimum of 3.0 and temperature optimum of 60 degrees C. It was stable in a wide pH range from 3.0 to 11.0, retaining 61% activity at pH 3.0 and 52% activity at pH 11.0. It retained 71% activity at 30 degrees C and 45% activity at 50 degrees C, up to 24 h. The enzyme activity was not inhibited by any of the metal ions tested except Hg2+, in the presence of which only 10% activity was retained. CONCLUSIONS: The 35 kDa chitinase from Microbispora sp. V2 has an acidic pH optimum and a high temperature optimum. It is fairly stable and active, and degrades chitin efficiently, although the growth of the culture and enzyme production is slow. SIGNIFICANCE AND IMPACT OF THE STUDY: This report is the first detailed study of a chitinase from Microbispora sp. V2, isolated from hot springs. The chitinase from Microbispora sp. V2 may have potential applications in the recycling of chitinous wastes, particularly due to its thermophilic and acidophilic character. Studies at molecular level may provide further insight on the chitinolytic system of Microbispora spp. with respect to the number and types of chitinases and their regulation.
Effects of angiotensin converting enzyme inhibitor on renal function in patients of membranoproliferative glomerulonephritis with mild to moderate renal insufficiency.
AIM: To determine the effect of enalapril, angiotensin-converting-enzyme inhibitor (ACE-I) on progression of renal insufficiency in primary membranoproliferative glomerulonephritis with mild to moderate renal insufficiency. METHOD: Thirty patients with histopathologically proved MPGN having hypertension (grade I and II of JNC-VI criteria of hypertension) and mild to moderate impairment of renal function (creatinine clearance varying from 30-80 ml/min, significant albuminuria and serum creatinine 1.2-3.0 mg/dl) were initially treated with diuretics and 3-blockers to bring down BP < 140/90 mm Hg. These patients were then randomly divided into three groups of 10 each, group I--Control; group II--Nifedipine and group III--Enalapril. In group II and III Nifidepine 30 mg/day and in group III Enalapril 10 mg/day respectively were added in addition and treatment was continued for nine months. These patients were followed up monthly for drug efficacy, side effects and any adverse drug reaction. RESULTS: Out of 30, 28 patients completed the study. At the end of nine months of treatment the patients of control group revealed significant increase in serum creatinine (1.65 +/- 0.38 to 2.17 +/- 0.31 mg/dl), blood urea (34.0 +/- 3.9 to 40.0 +/- 3.1 mg/dl), and 24 hours albuminuria (3.6 +/- 0.6 to 4.2 +/- 0.6 gm) and decrease in creatinine clearance (60.3 +/- 13.3 to 37.5 +/- 11.8 m/min); however, in enalapril group there was decrease in serum creatinine (1.72 +/- 0.45 to 1.24 +/- 0.58 mg/dl), blood urea (34.6 +/- 4.7 to 28.1 +/- 6.7 mg/dl) and 24 hours albuminuria (3.3 +/- 1.0 to 1.6 +/- 1.1 gm) and increase in creatinine clearance (56A +/- 15.8 to 77.1 +/- 23.5 ml/min). The patients on nifedipine showed statistically nonsignificant changes in creatinine clearance, blood urea and serum creatinine; while albuminuria increased from 3.0 +/- 1.3 to 3.9 +/- 0.4 gm/24 hours (p < 0.01). The blood pressure was well controlled in all patients. None of the patient had side effects leading to withdrawal of drugs. No adverse drug reaction was noted. CONCLUSION: ACE-I (enalapril) provided protection against the progression of renal insufficiency in patients of MPGN having hypertension with mild to moderate renal impairment. The renoprotective effects of ACE inhibitor (enalapril) is associated with substantial decrease in albuminuria.