Biomedical subjects

M G R Rajan

Publications and source records attributed to M G R Rajan.

6 recordsLinked to original sources

PubMed2006

Application of the polymerase chain reaction on formalin-fixed, paraffin-embedded tissue in the recognition of tuberculous osteomyelitis.

A retrospective series of 45 cases of chronic osteomyelitis collected over a period of 14 years was histologically classified into tuberculous osteomyelitis (25) and chronic non-granulomatous osteomyelitis (20). The tuberculous osteomyelitis group was divided into three subgroups: a) typical granulomas (13 cases); b) ill-defined granulomas (seven cases), and c) suspected granulomas (five cases). An in-house polymerase chain reaction amplifying the 245 bp nucleotide sequence, and capable of detecting 10 fg of DNA of Mycobacterium tuberculosis, was used on the DNA extracted from the paraffin blocks. The polymerase chain reaction was positive in 72% of cases (18) of tuberculous osteomyelitis, but when typical cases of tuberculous osteomyelitis with confirmed granulomas were considered (13), this increased to 84.6% (11). The chronic non-granulomatous osteomyelitis group gave positive polymerase chain reaction results in 20% of the cases (4). Our preliminary study on tuberculous osteomyelitis shows that the polymerase chain reaction can be a very useful diagnostic tool, since a good correlation was seen between typical granulomas and polymerase chain reaction with a sensitivity of 84.6% and a specificity of 80%. In addition, our study shows that tuberculous osteomyelitis can be diagnosed in formalin-fixed paraffin-embedded tissues in the absence of typical granulomas.

Chronic Disease↗

PubMed2005

Calcium iodate-another effective blocker of radioiodine uptake by the thyroid gland.

KI and KIO3 are the commonly used prophylactic drugs for the protection of thyroid glands against radioiodine. In this study, we have demonstrated the use of another iodine containing salt, calcium iodate [Ca(IO3)2], as an effective blocker of radioiodine uptake by the thyroid gland in rats. Ca(IO3)2 is permitted by the FDA as a food additive and is "generally regarded as safe" (GRAS, CFR No.1206). We have also compared the efficacy of Ca(IO3)2 with KIO3 in blocking thyroidal uptake of radioiodine, which could be important considering the better shelf life of Ca(IO3)2. Laboratory rats were administered 131I and stable iodide in the form of KIO3 or Ca(IO3)2 was given orally, 2 h after the administration of 131I. All the animals were monitored for whole body retention (WBR) of 131I, at 24 h and further for 14 d. The results of the present study provide us with evidence that Ca(IO3)2 can serve as another promising radioiodine blocker, and is as equipotent as KI/KIO3 in protecting the thyroid gland. We have not found any studies that examined the property of Ca(IO3)2 in blocking radioiodine uptake by the thyroid gland and the present study is an attempt in this direction.

Administration, Oral↗

PubMed2004

Difficulty in dislodging in vivo fixed radiostrontium.

Many trials based on the basic phenomena of isotopic dilution, adsorption, ion exchange, chelation, etc., have been attempted for the decorporation of radiostrontium, particularly Sr, after its entry in the in vivo system. We have recently demonstrated a non-isotopic carrier effect of some common calcium salts (calcium = 9 mg mL) to reduce the whole body retention of radiostrontium, if administered within 2 h after radiostrontium exposure and furthermore once daily, in rats, supplemented with calcium fortified diet. However, 25-30% of radiostrontium (compared to 50-60% in untreated animals) was still found to be retained in the animal even after 2 wk of treatment. Trial of some simple interventional measures, which would not adversely affect the animal metabolism, like pyrophosphate and magnesium sulfate, sodium citrate, chitin (a bio-absorbent), crown ether (a metal-chelator), and ammonium chloride, was therefore attempted to dislodge this remaining radiostrontium by switching over these animals to normal diet and subjecting them to different lines of treatment with these simple interventions through diet and drinking water separately for a further 4 wk. However, this remaining portion of radiostrontium is fixed in the bone and is difficult to dislodge.

Absorption↗

PubMed2004

Thyroid hormone binding protein abnormalities in patients referred for thyroid disorders.

BACKGROUND & OBJECTIVES: Thyroid hormone binding protein (THBP) abnormalities are the major cause of discordance in commonly performed total thyroxine (T4) and thyrotropin (TSH) estimations, though these do not interfere with thyroid hormone action. Determination of such abnormalities in patients showing discordant thyroid function tests (TFTs) is diagnostically important as it eliminates equivocal assessment of thyroid function and treatment especially where proper methodology for free T4 (FT4) estimation is not available. This study was undertaken to analyse the THBP abnormalities in the population attending thyroid clinic. Family members of affected patients were also screened to study the inheritance of quantitative TBG abnormalities. METHODS: Blood samples of 15000 consecutive patients over a period of 4 years (1994-1997) were tested for thyroid function. THBP abnormalities were studied using polyacrylamide gel electrophoresis autoradiography. Serum thyroxine binding globulin (TBG), free and total T4, total tri-iodothyronine (TT3) were assayed by radioimmunoassay methods. RESULTS: In our screening of 15,000 thyroid patients over a four year period, we found the presence of complete and partial TBG deficiency and TBG excess to be 1:2,500, 1:200 and 1:15,000 respectively. Our study on the families of three affected patients revealed X-chromosome linked inheritance pattern of TBG deficiency in two families and TBG excess in one family. INTERPRETATION & CONCLUSION: Our study suggests that it would be beneficial to rule out THBP abnormalities before interpreting results of TFTs, particularly when there is large discrepancy between T4 and TSH levels. In case of inherited THBP abnormalities, the family members of the affected individual should also be screened to avoid misdiagnosis and erroneous treatment in case they develop thyroid dysfunction in future.

Autoradiography↗

PubMed2003

An effective and better strategy for reducing body burden of radiostrontium.

In this study we have examined the effect of different calcium salts, Ca gluconate (CaG), Ca lactate (CaL), Ca carbonate (CaC) and Ca phosphate (CaP), on the clearance of radiostrontium (*Sr) administered either intraperitoneally (ip) (*Sr-ip group) or orally (*Sr-oral group) in rats. The influence of these Ca salts was examined in a group of animals administered *Sr ip, while the effect of three Ca salts (CaG, CaL and CaP) was studied in another group of rats given *Sr orally and compared with that of Ca alginate (CaA), normally advised for *Sr decorporation. Rats from both groups were subdivided into control and four experimental subgroups and were housed individually. The experimental subgroups were given the respective Ca salts (elemental Ca = 9 mg/rat/day) 2 h post 85Sr, and thereafter once daily. In the *Sr-ip group, CaG was administered ip while the other Ca salts were given orally. In the *Sr-oral group all Ca salts were administered orally. In addition, the diet of all the experimental subgroups was supplemented with the respective Ca salts to 2% elemental Ca. The whole-body retention (WBR) of *Sr in animals treated with Ca salts was found to be significantly reduced from 50-60% at 24 h to 20-30% at the end of 15 days compared with 70-80% at 24 h to 50-60% at the end of 15 days in the untreated control animals. The results strongly suggest that CaA could be replaced by any of the commonly used Ca salts for curtailing the WBR of *Sr. CaG which was administered ip, in the *Sr-ip group, was found to be more effective in reducing the WBR of *Sr.

Administration, Oral↗

PubMed2003

Changes in lipid peroxidation and free radical scavengers in kidney of hypothyroid and hyperthyroid rats.

Kidney weight was significantly decreased in hypothyroidism (induced by Na131I administration) and increased in hyperthyroidism (induced by thyroxine treatment) as compared to control in female Wistar rats. The tissue lipid peroxidation level remained unchanged in hyperthyroid rats but significantly increased in hypothyroid rats. Superoxide dismutase was decreased in both experimental groups but more so in hyperthyroid rats. Catalase was reduced significantly in hyperthyroid rats but remained unaffected in hypothyroid rats. Tissue glutathione peroxidase (GPx) activity was increased while reduced glutathione levels remained unaltered in both hypothyroid and hyperthyroid rats. Plasma GPx activity was significantly low in both the hypothyroid and hyperthyroid rats. The results suggest alterations in the oxidative stress in hypothyroid and hyperthyroid rat kidneys with concomitant changes of free radical scavengers.

Animals↗