Lung clearance of intratracheally instilled 99mTc-tobramycin using pulmonary surfactant as vehicle.
(1/98)
1. The use of pulmonary exogenous surfactant as a vehicle for intratracheally administered antibiotics to improve local antimicrobial therapy has been proposed. The present study investigated lung clearance rates in the rat of intratracheally instilled technetium labelled tobramycin with and without the addition of surfactant to the antibiotic solution. 2. The influence of surfactant on 99mTc-tobramycin lung clearance rates was studied dynamically with a gamma-camera in anaesthetized spontaneously breathing animals and in mechanically ventilated animals. 3. The results show that instillation of 99mTc-tobramycin with use of surfactant as vehicle significantly increases 99mTc-tobramycin lung clearance compared to instillation of 99mTc-tobramycin solution alone (P=0.006 between the two spontaneously breathing groups of animals and P=0.02 between the two ventilated groups of animals, ANOVA for repeated time measurements). The half life (t1/2) of composite clearance curves in spontaneous breathing animals was 147 min for animals receiving 99mTc-tobramycin versus 61 min for animals receiving 99mTc-tobramycin with surfactant. In mechanically ventilated animals this was 163 min versus 51 min, respectively. 4. It is concluded that exogenous surfactant, used as vehicle for intratracheally instilled 99mTc-tobramycin, increases lung clearance rate of 99mTc-tobramycin in rats. (+info)
Gastric emptying and intestinal transit of pancreatic enzyme supplements in cystic fibrosis.
(2/98)
OBJECTIVE: To investigate gastric emptying and intestinal transit of pelleted pancreatin in relation to food boluses. METHODS: Dual isotope scintigraphy combined with breath hydrogen sampling was used to track the concurrent gastric emptying and intestinal transit of 111indium labelled microspheres and a 99mtechnetium labelled tin colloid test meal. Twelve pancreatic insufficient cystic fibrosis patients aged 5 to 38 years performed the study. RESULTS: 50% gastric emptying times showed patient to patient variation. The mean discrepancy in 50% gastric emptying times between the two labels was > 67 minutes. Mean small bowel transit time for the food bolus was prolonged at 3.6 minutes. A significant correlation was seen between weight standard deviation score and 50% emptying time for pancreatin (r = +0.73). CONCLUSION: Gastric mixing of food and pancreatin may be limited by rapid emptying of microspheres. Patients with high dosage requirements could benefit from changing the pattern of their pancreatin supplementation. (+info)
Chemotactic peptide uptake in acute pancreatitis: correlation with tissue accumulation of leukocytes.
(3/98)
Chemotactic peptides bind specifically to receptors on leukocyte membranes. This property makes them prospective vehicles to evaluate inflammation and infection. We used two well-established models of acute pancreatitis to quantitate the binding of the chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine-lysine (fMLFK) to leukocytes and its correlation to degree of organ inflammation. Uptake of the (99m)Tc-labeled nicotinyl hydrazine-derivatized chemotactic peptide analog fMLFK-HYNIC was measured in blood, pancreas, lung, and muscle specimens in rats with edematous or necrotizing pancreatitis and was compared with neutrophil sequestration assessed by myeloperoxidase activity and histology. Chemotactic peptide uptake in the pancreas was increased in mild and severe pancreatitis compared with controls, with higher levels in severe than in mild disease, and correlated with tissue myeloperoxidase activity (r = 0.7395, P < 0.001). Increased pulmonary uptake only in severe pancreatitis reflected pancreatitis-induced neutrophil sequestration in the lungs. Muscle uptake was unchanged compared with controls. Edema formation did not affect chemotactic peptide uptake. The data suggest that uptake of chemotactic peptides can contribute to quantitative assessment of neutrophils in localized inflammatory processes and is independent of associated edema formation or microcirculatory compromise. (+info)
Scintigraphic detection of bile leak and follow-up in a post-cholecystectomy patient with recognition of tail sign.
(4/98)
Early detection of site and extent of biliary tract disruption can significantly reduce mortality and morbidity in a postoperative biliary leak. We report a case in whom extent and location of post surgical biliary leak was detected with the help of 99mTc BULIDA cholescintigraphy and showed a good correlation with "T" tube cholangiography. Cholescintigraphy was also useful in assessing the follow up of this patient. We conclude that 99mTc BULIDA cholescintigraphy is a non-invasive, safe, simple and sensitive procedure in the detection of the site, extent of the leak and in follow up of the postoperative biliary leak. (+info)
The effect of vascular endothelial growth factor on angiogenesis: an experimental study.
(5/98)
OBJECTIVE: to evaluate the effects of exogenous vascular endothelial growth factor (VEGF) on angiogenesis in a rabbit model of persistent hind limb ischaemia. MATERIALS AND METHODS: ischaemia was induced in the hind limbs of 42 New Zealand white rabbits divided into six groups, each of 7 animals. Group 1a and 1b received intramuscular injections of 1 and 2 mg VEGF/day, respectively, into the ischaemic hind limb for 10 days beginning on postoperative 11th day, and group 1c received IM injections of saline only. Group 2a and 2b received similar regimen of VEGF, but administered intra-arterially. Group 2c served as controls. Perfusion of the ischaemic limb was evaluated by thigh blood pressure and thigh circumference at 10, 25 and 40 days following limb ischaemia in all animals and by digital subtraction angiography, perfusion scans, histological examination of capillary density in 2 animals from each group. RESULTS: thigh pressure index and thigh circumference improved significantly in the VEGF treated animals (Groups 1a,b and 2a,b). Collateral formation, as assessed by angiography, scintigraphy and by histological examination, indicated marked formation of collaterals in the VEGF treated animals as compared with the controls. This was most pronounced in groups receiving the highest dose of VEGF. CONCLUSION: these data suggest that VEGF promotes angiogenesis, that the route of administration is unimportant, but that a dose-response relationship is present in this experimental ischaemic hind limb model. (+info)
Preoperative evaluation of sentinel lymph node status in melanoma by means of (99m)Tc-MIBI and lymphoscintigraphy: a case report.
(6/98)
Previous reports have shown that (99m)Tc-sestamibi (MIBI) could detect clinically occult metastatic melanoma lesions. This article reports on a patient with invasive melanoma of the right heel in whom the sentinel node status was preoperatively evaluated with this tracer. Although regional lymph nodes were clinically negative, (99m)Tc-MIBI scintigraphy showed focal increased tracer uptake in the right groin that corresponded to the location of 2 sentinel nodes visualized by lymphoscintigraphy with (99m)Tc-colloidal rhenium sulfide performed the same day. A gamma-probe was used intraoperatively to guide the excision of the sentinel nodes that were further classified as metastatic by histopathology. This double-technique approach is technically feasible and has the potential of selecting a group of patients who might benefit from a selective complete lymphadenectomy. (+info)
Radioguided sentinel lymph node biopsy in malignant cutaneous melanoma.
(7/98)
The procedure of sentinel lymph node biopsy in patients with malignant cutaneous melanoma has evolved from the notion that the tumor drains in a logical way through the lymphatic system, from the first to subsequent levels. As a consequence, the first lymph node encountered (the sentinel node) will most likely be the first affected by metastasis; therefore, a negative sentinel node makes it highly unlikely that other nodes in the same lymphatic basin are affected. Although the long-term therapeutic benefit of the sentinel lymph node biopsy per se has not yet been ascertained, this procedure distinguishes patients without nodal metastases, who can avoid nodal basin dissection with its associated risk of lymphedema, from those with metastatic involvement, who may benefit from additional therapy. Sentinel lymph node biopsy would represent a significant advantage as a minimally invasive procedure, considering that an average of only 20% of melanoma patients with a Breslow thickness between 1.5 and 4 mm harbor metastasis in their sentinel node and are therefore candidates for elective lymph node dissection. Furthermore, histologic sampling errors (amounting to approximately 12% of lymph nodes in the conventional routine) can be reduced if one assesses a single (sentinel) node extensively rather than assessing the standard few histologic sections in a high number of lymph nodes per patient. The cells from which cutaneous melanomas originate are located between the dermis and the epidermis, a zone that drains to the inner lymphatic network in the reticular dermis and, in turn, to larger collecting lymphatics in the subcutis. Therefore, the optimal route for interstitial administration of radiocolloids for lymphoscintigraphy and subsequent radioguided sentinel lymph node biopsy is intradermal or subdermal injection. (99m)Tc-Labeled colloids in various size ranges are equally adequate for radioguided sentinel lymph node biopsy in patients with cutaneous melanoma, depending on local experience and availability. For melanomas along the midline of the head, neck, and trunk, particular consideration should be given to ambiguous lymphatic drainage, which frequently requires interstitial administration virtually all around the tumor or surgical scar from prior excision of the melanoma. Lymphoscintigraphy is an essential part of radioguided sentinel lymph node biopsy because images are used to direct the surgeon to the sites of the nodes. The sentinel lymph node should have a significantly higher count than that of the background (at least 10:1 intraoperatively). After removal of the sentinel node, the surgical bed must be reexamined to ensure that all radioactive sites are identified and removed for analysis. Virtually the entire sentinel lymph node should be processed for histopathology, including both conventional hematoxylin-eosin staining and immune staining with antibodies to the S-100 and HMB-45 antigens. The success rate of radioguidance in localizing the sentinel lymph node in melanoma patients is approximately 98% in institutions that perform a high number of procedures and approaches 99% when combined with the vital blue-dye technique. Growing evidence of the high correlation between a sentinel lymph node biopsy negative for cancer and a negative status for the lymphatic basin-evidence, therefore, of the high prognostic value of sentinel node biopsy-has led to the procedure's being included in the most recent version of the TNM staging system and starting to become the standard of care for patients with cutaneous melanoma. (+info)
Bone scintigraphy as an adjunct for the diagnosis of oral diseases.
(8/98)
Bone scintigraphy is a very sensitive method for the detection of osteoblastic activity of the skeleton. The technique consists of imaging the uptake of bone-seeking radiopharmaceuticals, particularly technetium-99m labeled diphosphonates, in the mineral component of bone, which consists of hydroxyapatite crystals and calcium phosphate, as well as in the organic matrix such as collagen fibers. Plain radiographs, computed tomography, and magnetic resonance imaging are classified as structural imaging modalities, whereas bone scintigraphy is a functional method. In many cases, radionuclide imaging techniques are the only means by which early physiologic changes that are a direct result of biochemical alteration may be assessed, before significant bone mineral changes can be detected by other means. Since many oral diseases may cause metabolic changes in the oromaxillofacial complex, it would be of great value to use bone scintigraphy to evaluate more completely some conditions involving the bones in the region to formulate more appropriate treatment plans. Based upon the current literature, the authors discuss the possible applications of bone scintigraphy as a diagnostic and treatment planning adjunct for oral diseases. Bone scintigraphy has proven particularly useful in the study of malignant lesions and in the evaluation of vascularized bone grafts used for maxillofacial reconstructions. (+info)