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Biomedical subjects

G T Krishnamurthy

Publications and source records attributed to G T Krishnamurthy.

At least 73 records · Page 4Linked to original sources
PubMed1981

Radiation dose calculation for Tc-99m HIDA in health and disease.

Radiation dose from Tc-99m HIDA has been calculated for normal subjects and for patients with various hepatobiliary diseases classified into four groups based on serum bilirubin level. The calculation was performed on biokinetic radioactivity data from blood, urine, liver, gallbladder, and intestines, using a biological approach that included a catenary model of the digestive organs. For normal subjects the critical organs were the gallbladder and the upper and lower large intestine, with doses of 910, 300, 200 mrad/mCi, respectively. The bone marrow, ovaries, and testes received 24, 62, and 4 mrad/mCi. For Group 4 patients with severe hepatobiliary disease (bilirubin greater than 10 mg/dl), the critical organs were the kidney, urinary bladder, and gallbladder, with doses of 130, 110, and 100 mrad/mCi. The bone marrow, ovaries, and testes received 9, 13, and 6 mrad/mCi. Thus the critical organs and overall radiation doses to organs change between health and disease.

Bilirubin↗
PubMed1980

Neutralizing antibodies to bovine thyrotropin in immunized patients with thyroid cancer.

Bovine thyrotropin (bTSH) was administered to 17 patients who had thyroid carcinoma. Anti-bTSH antibodies in the patients' sera were detected by three methods: 1) cross-reaction of sera in a homologous bTSH RIA, 2) [125I]bTSH binding to the patients' sera using charcoal to separate bound from free fractions, and 3) gel filtraton to detect [125I]bTSH bound to anti-bTSH in patients' sera. Immunoreactive anti-bTSH antibodies were thus demonstrated in 14 patients. These patients showed specific binding of their sera to [125I]bTSH with the charcoal separation of free from bound hormone. A high titer of antiserum (1:10,000) was found in those patients whose sera reacted strongly in the bTSH RIA (greater than 50 mu U/ml). The binding capacity of the serum of 1 patient was estimated as 2,600 mu U/ml serum. Ten of the patients' sera which showed immunoreactivity to bTSH neutralized bTSH activity in the McKenzie mouse bioassay but did not neutralize the activity of human TSH in this bioassay. Repeated administration of bTSH to 14 patients resulted in development of immunoreactive and neutralizing anti-bTSH antibodies. Development of immunological resistance to bTSH appears inevitable in patients who receive repeated injections of this hormone. Because of the loss of effectiveness of bTSH by antibody formation, the repeated diagnostic and therapeutic use of bTSH is not recommended.

Animals↗
PubMed1978

Human reaction to bovine TSH: concise communication.

The incidence of allergic reactions to bovine TSH and its relation to dose have been studied in 42 patients with thyroid cancer who had total ablation of functioning thyroidal tissue and have been followed prospectively for up to 25 yr. Of these patients, 43% showed an allergic reaction to bovine TSH. The remaining 57% have shown no reaction, even though they have received cumulative TSH doses larger than those who did show a reaction. The reaction rate is linear up to a cumulative dose of 150 units and is not dose-related therafter.

Drug Hypersensitivity↗
PubMed1977

Distribution pattern of metastatic bone disease. A need for total body skeletal image.

Distribution patterns of metastatic bone disease in 62 patients with soft-tissue cancers showed that 60% of bone lesions were located in the axial and 40% in the appendicular skeleton. Thirteen percent of the lesions were in appendicular regions not usually included in routine imaging studies. The majority of the metastatic skeletal lesions were clinically asymptomatic. The serum alkaline phosphatase level is a poor indicator of early bone metastases.

Adult↗
PubMed1977

Radioiodine I-31 therapy in the management of thyroid cancer. A prospective study.

The therapeutic value of I-131 ablation therapy following thyroidectomy for thyroid cancer was evaluated in 54 patients in a prospective study of 25 years. Thirteen (24%) patients had follicular, 24 (44%) papillary, 13 (24%) mixed papillary-follicular, two (4%) Hurthle cell and two (4%) had undifferentiated cell type tumor. Twenty-four (44.5%) patients had metastases at the time of I-131 therapy mainly to cervical and mediastinal lymph nodes, and less frequently to bone, brain, lung, and liver. After surgical thyroidectomy, the mean cumulative dose of I-131 required to achieve therapeutic ablation of functioning post-surgical remnants or tumor metastases was 163.4 mCi. The recurrence rate for patients with metastases was 56% and those without metastases was 25%. Ten patients showed recurrence of I-131 accumulating tissue five to 10 years after initial total ablation. The total mean cumulative dose of I-131 administered for both followup diagnostic studies, and initial and follow-up therapy was 245.3 mCi. Seven deaths were attributable to thyroid cancer, five with differentiated and two with anaplastic cell type tumors. Three of the four patients with differentiated cell type tumors had metastases to brain or bone. Their response to therapy was similar to those patients with anaplastic cell type tumors. In contrast, there were no deaths due to thyroid cancer when total ablation was achieved and maintained. After ablation, all patients were maintained on maximum tolerated doses of thyroid extract or thyroxin. No significant complications attributable to the therapeutic doses of I-131 employed in this series were noted.

Adenocarcinoma↗
PubMed1977

Technetium-99m-Sn-pyrophosphate pharmaco-kinetics and bone image changes in parathyroid disease.

Skeletal abnormalities in 12 patients with primary hyperparathyroidism, five patients with pseudohypoparathyroidism, and three patients with hypoparathyroidism were studied to compare the diagnostic sensitivity of bone radiologic examination to that of radionuclide studies using 99mTc-Sn-pyrophosphate (99mTc-PPi) a skeletal-seeking radiopharmaceutical. The results were compared with bone mineral content as measrued by the Norland--Cameron densitometer. Kinetic data of the blood disappearance and plasma clearance of 99mTc-PPi were obtained and compared with data of control subjects without evidence of parathyroid disease. Bone imaging with 99mTc-PPi may be more sensitive than routine skeletal radiographs and bone mineral analysis for the evaluation of skeletal abnormalities in patients with parathyroid disfunction. The enhanced plasma clearance of the tracer observed in patients with primary hyperparathyroidism may reflect the direct effect of excessive parathyroid hormone on the renal handling of 99mTc-Sn-pyrophosphate.

Adolescent↗
PubMed1977

Multiform thyroid cancer-scintigraphic and echographic features.

In a patient with multinodular goiter, one of the three solid nodules harboring follicular carcinoma appeared functional in the 99mTc-pertechnetate image, yet "cystic" in both A-and B-mode echogram studies. The other two nodules corresponded in their image and echogram features and contained papillary and anaplastic carcinomas, and Hashimoto's thyroiditis. Clinical acumen proved to be the best guide in the management of this patient.

Adenocarcinoma↗
PubMed1976

Spontaneous drainage of a large cystic tumor.

A case is described of a 58 year old male who presented with a large mass on the left side of the abdomen which was found to be cystic by ultrasound. A presumptive diagnosis of pancreatic pseudocyst was made. Shortly thereafter, the mass drained spontaneously further suggesting this diagnosis. At surgery a month later, however, the mass was found to be a metastic leiomyosarcoma with cystic degeneration that had eroded into the gastric wall. This case serves to illustrate that cystic abdominal masses, even ones that drain spontaneously into the gastrointestinal tract, may not be pancreatic pseudocysts.

Diagnosis, Differential↗
PubMed1976

Pharmaco-kinetics of current skeletal-seeking radiopharmaceuticals.

The blood clearance of all current bone-seeking radiopharmaceuticals is biexponential during the first four hours after injection. Exponent I represents bone uptake and its clearance half-time is less than 30 min. Exponent II represents mainly urinary excretion and its clearance half-time varies from 168 to 512 min. The blood background is highest with 99mTc-labeled polyphosphate (Tc-Poly) and lowest with sodium fluoride (F-18); 99mTc-labeled diphosphonate (Tc-Dip) and 99mTc-labeled pyrophosphate (Tc-Pyro) show intermediate blood levels. The slower blood clearance of 99mTc-phosphate complexes in comparison with F-18 is due primarily to their increased protein binding. Tc-Poly blood clearance, which is slower than that of Tc-Dip and Tc-Pyro, is due primarily to its increased red cell binding and the larger size of its molecule. Bone uptake and urinary excretion of all 99mTc-labeled phosphate complexes are approximately the same: in the range of six to ten per cent in the blood, 30-33% in the urine, and 55-58 percent in the bone and other tissues. F-18 concentration in the bone is almost 1.5 times that of the 99mTc-labeled phosphate complexes. The sensitivity and resolution of lesions are identical for all 99mTc-labeled phosphate complexes and are far better than those for F-18. No toxicity is noted with the amount of phosphate present in the marketed kits, and it appears reasonable to use the minimal amount so long as efficiency is not compromised.

Biopharmaceutics↗
PubMed1976

Scintiscan characteristics of normal thyroid gland in a region of known iodine intake.

Morphological features of a normal thyroid gland in a geographical region where the daily iodine intake is about 1 mg are established. The mean weight of the thyroid gland is 31.3 gm with a range from 19 to 43 gm. Oblique length of the right lobe is 5.0 cm and that of the left lobe 4.8 cm. The surface area of the right and left lobes is 9.7 and 9.1 cm2, respectively. The weight of the thyroid gland calculated on the basis of the scan obtained with 99mTcO4 is quite variable and shows poor correlation (gamma = 0.40) with the weight obtained on the basis of I-131 scan. It is suggested that the criteria of normalcy be established regionally based on iodine intake, and that an isotope of iodine be used in calculating the weight of thyroid gland for dosimetry purposes.

Diet↗
PubMed1976

Radionuclide scanning in the evaluation of Kaposi sarcoma.

A patient with Kaposi sarcoma showed increased uptake of sodium pertechnetate Tc 99m over both clinically evident and occult regions of involvement. The clinically negative but scan-positive regions showed pathologic lesions by biopsy. Gallium citrate Ga 67 and bleomycin sulfate labeled with indium 111 (111In) did not concentrate in the lesions, which suggest that Kaposi sarcoma, despite its resemblance to lymphoma, differs from lymphoma substantially with reference to raionuclide uptake. This report confirms that sodium pertechnetate Tc 99m is the most sensitive agent for diagnostic and therapeutic evaluation of patients with Kaposi sarcoma and suggests taht gallium citrate Ga 67 or bleomycin 111In may be useful in the differentiation of Kaposi sarcoma from lymphoma.

Animals↗
PubMed1976

Diagnosis of superior vena caval obstruction without syndrome.

Ten patients with known malignant intra-thoracic tumors and no evidence of superior vena cava syndrome were evaluated by means of scintillation camera superior venacavograms. Four of the ten patients proved to have unsuspected involvement of the superior vena cava or its tributaries. The scintillation camer superior venacavogram provides a quick, safe, and accurate method of evaluating the patency of the SVC and its tributaries. We suggest that it should be routinely performed on all patients prior to beginning radiation therapy for malignant intra-thoracic tumors.

Humans↗
PubMed1975

Labeled metronidazoles as potential new agents for amebic hepatic abscess imaging.

Two new radiopharmaceuticals were developed as possible agents for demonstrating the presence of hepatic amebic abscesses by selective accumulation of these agents in the abscess contents. These agents are: 131I-labeled Bromometronidazole, that has been shown to possess some of the antibiotic activity of metronidazole or Flagyl; and a Technetium 99m-penicillamine-Flagyl complex. A method of radioiodination has been devised which can be performed in radiopharmaceutical laboratories. Both radiopharmaceuticals are of very low toxicity. Distribution studies in animals show accumulation in the liver and elimination by way of the gallbladder. Scintillation camera studies depict a rapid uptake by the liver with subsequent biliary excretion. Animal models for the study of hepatic amebic abscesses are not available. A human patient with suspected amebic abscesses has been studied with negative findings that were confirmed at surgery. Collaborative studies are now in progress in several areas of the world where amebiases is endemic.

Animals↗
PubMed1975

Technetium-99m polyphosphate bone image for early detection of skeletal metastasis. Correlation with other diagnostic parameters.

Technetium 99m-polyphosphate bone images are correlated with bone roentgenography, and serum calcium, phosphorus and alkaline phosphatase in 91 patients with suspected bone metastasis. Technetium polyphosphate bone images are the most sensitive and serum level of calcium and phosphorus are the least sensitive indicator of bone lesions. Bone roentgenography is not as sensitive as technetium polyphosphate images. Abnormal bone images with normal or abnormal bone roentenography associated with increased alkaline phosphatase in the absence of liver metastasis are highly suggestive of metastatic bone disease. Abnormal bone images adjoining the joints, associated with normal serum alkaline phosphatase and abnormal joint roentgenography suggest arthritis. It is recommended that technetium 99m-labelled phosphate bone images are considered to be the diagnostic procedure of choice to detect skeletal lesions. Polyphosphate bone images are highly sensitive, with the combination of elevated alkaline phosphatase they become relatively more specific for a metastatic bone disease.

Alkaline Phosphatase↗
PubMed1975

Cholescintigraphy with 99mTc-penicillamine.

D-pencillamine labeled with 99mTc (Tc-Pen) was used for cholescintigraphy in dogs and man. Satisfactory images of the gallbladder were obtained using a scintillation camera fitted with a pinhole collimator. The results of cholescintigraphy and contrast cholecystography compared favorably. The authors suggest that Tc-Pen is taken up by the hepatocytes and excreted into the bile canaliculi which enter the gallbladder. Tc-Pen may prove to be an ideal agent for evaluation of hepatocellular function.

Animals↗