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Biomedical subjects

K Joseph

Publications and source records attributed to K Joseph.

At least 55 records · Page 3Linked to original sources
PubMed1994

[Scintigraphy of parathyroid adenomas with 99mTc-sestamibi in an endemic goiter area].

Recently 99mTc-Sestamibi (MIBI) has been introduced into parathyroid imaging. The purpose of this study was to evaluate the MIBI scan in an endemic goiter area. 25 patients with primary and 9 with secondary hyperparathyroidism (HPT) underwent a MIBI scan one day prior to surgical exploration of the neck. Cervicothoracic planar scintigraphy was performed 5, 15 and 120 min after i.v. injection of 444 MBq of 99mTc-Sestamibi. The MIBI scan correctly detected 20 of 25 adenomas in 25 patients with pHPT. In only 6 of 9 patients with parathyroid hyperplasia a focal uptake was found. The cause of one false-positive result in the control group was an increased MIBI uptake by a follicular adenoma of the thyroid. Parathyroid scintigraphy using 99mTc-Sestamibi as a single radiopharmaceutical is as sensitive in detecting and localizing parathyroid adenomas as the Tl/Tc-scintigraphy. Due to a high prevalence of thyroid adenomas in an endemic goiter area a higher rate of falsely positive results may be expected.

Adenoma↗
PubMed1993

Preoperative localization of gastrointestinal endocrine tumors using somatostatin-receptor scintigraphy.

OBJECTIVE: The purpose of this study was to determine the value of somatostatin-receptor scintigraphy (SRS) in the preoperative localization of gastrointestinal endocrine tumors. The authors report their preliminary experiences with this new technique as compared to conventional imaging studies like computed tomography (CT) and ultrasonography (US). SUMMARY BACKGROUND DATA: Most endocrine tumors possess high-affinity somatostatin-receptors. Using the stable, 111Indium labelled somatostatin analogue pentatreotid, which binds to these receptors, it is possible to detect somatostatin-receptor-positive tumors scintigraphically. METHODS: In nine patients with various gastrointestinal endocrine tumors, SRS, CT, and US were performed before surgical exploration. The preoperative imaging studies and intraoperative ultrasound (IOUS) were then compared to findings on surgical exploration. RESULTS: Twelve primary tumors were found in 8 patients at surgical exploration. These primary tumors were correctly identified with SRS in five patients, with US in four patients, and with CT in three patients. In one patient with the Zollinger-Ellison syndrome, scintigraphy suggested a tumor in the area of the hepatoduodenal ligament, while CT and US had negative results. The underlying gastrinoma could not be identified despite extensive surgical exploration. Scintigraphy, CT, and US showed comparable results in the detection of metastases in four patients. CONCLUSIONS: The data from this small series suggest that SRS is helpful in the preoperative localization of gastrointestinal endocrine tumors.

Adult↗
PubMed1993

Bronchoalveolar lavage. Quantitation of intraalveolar fluid?

A precise calculation of the amount of intraalveolar fluid is the basis of a quantitative analysis of intraalveolar compounds. Different approaches have been made to cover this important problem. Here, we report a comparative study with five markers: 99mTc-DTPA, 51Cr-EDTA, inulin, urea, and methylene blue in animal experiments as well as in human experiments. The marker substances were added to the lavage fluid, and the "dilution" of the markers, i.e., the alveolar fluid, was calculated. The results showed that in animals with healthy lungs the tracer methods are able to calculate amounts of intraalveolar fluid that are comparable to morphologic findings. In animals as well as in humans, methylene blue and inulin were shown to be useless in determining alveolar fluid volume compared with the tracer methods. In humans, the calculations with the urea method and with Tc-DTPA were in the same magnitude, but there was no individual correlation. We conclude that, at present, the methods to quantitate alveolar fluid volume lack precision and add nothing to a deeper understanding of alveolar biology.

Animals↗
PubMed1993

[Receptor scintigraphy using 111In-pentetreotide in endocrine gastroenteropancreatic tumors].

Receptor scintigraphy with 111In-pentetreotide is a complementary imaging technique with a sensitivity of 88% for the localization of the primary tumor and its metastases in patients presenting with the clinical and biochemical symptoms of an endocrine tumor of the gastrointestinal tract or the pancreas. As a whole-body scintigraphic technique it covers all body regions and is also able to reveal small tumors which can only be detected with difficulty or not at all by the usual imaging methods. In 104 patients with GEP tumors or after operative removal of such tumors, receptor scintigraphy proved to be superior to ultrasound and computed tomography in 34%, equal in 52% and inferior in 14% of the cases.

Female↗
PubMed1993

Receptor scintigraphy with 111In-pentetreotide for endocrine gastroenteropancreatic tumors.

Receptor scintigraphy with 111In-pentetreotide is a simple method with a sensitivity of 86% for the localization of the primary tumor and its metastases in patients presenting with the clinical and biochemical symptoms of an endocrine tumor of the gastrointestinal tract or the pancreas. As a whole-body scintigraphic technique it covers all body regions and is also able to reveal small tumors which either cannot be detected or can only be detected with difficulty by the usual imaging methods. In 85 patients with GEP tumors or after operative removal of such tumors, receptor scintigraphy proved to be superior to ultrasound and computed tomography in 34%, equal in 52%, and inferior in 14% of the cases.

Aged↗
PubMed1992

Effects of phorbol myristate and ionomycin on in vitro growth of aged Peyer's patch T and B cells.

The proliferative responses of Peyer's patch (PP) T cells from aged BALB/c mice to concanavalin A (Con A) are considerably reduced, as compared to those of the young (P < 0.001). This reduced reactivity of aged T cells could be partly, but not entirely, corrected by interleukin 2 (IL-2) (P < 0.001). PP T cells from aged mice responded synergistically to a protein kinase C (PKC) activator, phorbol myristate acetate (PHA), plus a calcium ionophore, ionomycin, at much lower concentrations than to Con A (P < 0.001); however, the maximal proliferative response still remained nearly at 8/10th of the young (P < 0.01) and higher levels of PMA (but not of ionomycin) were required (P < 0.001). Addition of IL-2 restored the diminished response to the levels of the young T cells (P < 0.05), but that of Con A did not (P > 0.05). The proliferative responses of PP B cells to lipopolysaccharide (LPS) do not differ from those of the young (P > 0.05), but the spontaneous proliferation of aged (unstimulated) B cells is enhanced nearly twofold versus that of the young (P < 0.001). Like the PP T cells, PP B cells from aged mice also responded synergistically to PMA plus ionomycin but to a lesser degree than those of the young under the same stimulation (P < 0.01). Their maximal proliferation required higher levels of PMA, but not of ionomycin and was also diminished (P < 0.01), compared to that of the young. B cell stimulatory co-factors, IL-4 and IL-6, failed to affect the response of aged and young B cells to PMA plus ionomycin (P > 0.05), whereas LPS remediates the reduced response of aged B cells to PMA plus ionomycin. Thus, T and B cells from senescent PP demonstrate an impaired proliferative responsiveness via the Ca-dependent PKC pathway. A T cell mitogen and B cell stimulatory cytokines did not alter this activation pathway, once optimally stimulated. Whereas, T cell stimulatory cytokine IL-2 and B cell mitogen LPS could restore the age-associated decline of the corresponding lymphocyte subsets, T and B cells, in activation of the Ca-dependent pathway. The altered transmembrane signal transduction appears to be intrinsically defective in these aged PP T and B cells.

Aging↗
PubMed1992

Hemophan versus hemophan--a philippic against the suggestion of constant membrane quality.

All statements referring to biocompatibility of dialyzers depend on the suggestion of a constant and reproducible structure of the investigated membrane material. The data presented here strike this concepts in case of hemophane. Two commercially available hemophane dialyzers, the GF MC 120 (Gambro) and the MO 450 (SMAD) membranes, were compared. Significant differences could be seen in the induction of leukopenia and leukocyte sequestration reaction within patients lungs, but also in capacity to influence granulocyte oxidative metabolism and release of granular enzymes. According to these data it seems questionable whether hemophane is a membrane material with constant structure and quality normally expected for products bearing trade names. Excluding other differences (like surface-area or sterilization method) variable amounts of DEAE substituents and/or an inconstant distribution of the DEAE groups within the membranes may be the most possible reason responsible for the differences found. The study underlines the urgent need of an exact physico-chemical characterization of dialyzer membranes and is therefore a challenge for free publication of such basic data by the producers.

Biocompatible Materials↗
PubMed1991

Early developmental profile of ornithine decarboxylase in the frog, Microhyla ornata and its regulation by polyamines.

Ornithine decarboxylase (ODC) activity and polyamine levels were measured during early development of the frog, Microhyla ornata. ODC activity was found to be high and it showed three major peaks during the first 60 hr of development. Putrescine and spermidine levels increased gradually during the above period with little change in spermine. Treatment of developing embryos with exogenous putrescine and spermidine prevented the normal increase in ODC activity. Spermine did not have any significant effect. Addition of ornithine also prevented the increase in ODC activity. Experiment using exogenous ornithine and alpha-methylornithine revealed that formation of putrescine and/or spermidine from ornithine is necessary for the suppression of ODC to occur. Suppression of ODC takes place even if conversion of putrescine to spermidine is blocked, indicating that putrescine, independent of its conversion to spermidine, also plays a role in ODC regulation.

Animals↗
PubMed1991

Assessment of ventricular function with first-pass radionuclide angiography using technetium 99m hexakis-2-methoxyisobutylisonitrile: a European multicentre study.

In the context of a multicentre study on the use of technetium 99m hexakis-2-methoxyisobutylisonitrile (99mTc-Sestamibi), we evaluated the accuracy of the ventricular function assessed at rest by means of first-pass radionuclide angiocardiography acquired during the injection of the tracer for myocardial perfusion scintigraphy. The results were compared with first-pass studies performed using reference tracers sodium pertechnetate Tc 99m or technetium 99m diethylene triamine penta-acetic acid or with gated radionuclide angiocardiography. A total of 66 patients of the 105 enrolled in the study could be evaluated. The comparison of the first-pass studies was possible in 33 subjects with regard to the left ventricular ejection fraction, yielding r = 0.909 (P less than 10(-6)), and in 22 cases with regard to the right ventricular ejection fraction, yielding r = 0.712 (P less than 0.001). The comparison between the first-pass study using 99mTc-Sestamibi and the equilibrium gated radionuclide angiocardiography was possible for the left ventricular ejection fraction in 26 cases, with r = 0.937 (P less than 10(-6)), and for the right ventricular ejection fraction in 15 subjects, with r = 0.783 (P less than 0.001). In conclusion, the assessment of ventricular function performed by acquiring a first-pass radionuclide angiocardiograph during the injection of 99mTc-Sestamibi for perfusion myocardial scintigraphy can be considered reliable and accurate, when compared with the usually employed techniques. This result confirms the feasibility of a combined evaluation of perfusion and function at rest and during stress testing, which represents one of the most interesting advantages offered by the use of 99mTc-Sestamibi.

Coronary Disease↗
PubMed1991

IL4, IL5 and IL6-mediated regulation of immunoglobulin (Ig) heavy chain class switching and Ig production by gut-associated lymphoid tissue (GALT) B cells from athymic nude (nu/nu) mice.

Gut mucosal immunoglobulin (Ig) isotype expression and secretion are known to be regulated by B cell-stimulatory factors (BSF), lymphokines or cytokines from T and non-B cells. The class and amount of Ig secreted appear to depend on the presence of a combination of these factors. The effects of IL-4 and IL-5 on Ig class switching by gut mucosal B cells remain controversial. To shed further light on this issue, young (1-2 months old) athymic nu/nu murine GALT B cells were chosen, because the possibility of in vivo effects of T cells on B cells (in particular at the levels of transcription and translation without changes in surface Ig phenotype expression) cannot be excluded. The results are summarized below. IL-4, IL-5 and IL-6 alone or in combination do not act as IgA heavy chain switch cofactors, but IL-5 and IL-6 do act at least as B cell terminal differentiation factors for any isotype-specific gut-associated lymphoid tissue (GALT) (mesenteric lymph node) B cells in the presence or absence of LPS. The BSF have augmenting effects on class-specific Ig production by GALT sIgM-bearing B cells, when these are treated with the BSF alone. IL-4 alone or in combination with other BSF prevents LPS-stimulated IgM production. BSF without LPS do not evoke production of significant amounts of IgG and IgA by high density (HD) and low density (LD) sIgM-bearing B cells; IgM is synthesized only in small amounts of LD sIgM-bearing B cells in the presence of IL-5 and/or IL-6. There is no difference in the responsiveness of GALT and spleen sIgM-bearing B cells to the BSF.

Animals↗
PubMed1990

Kinetics of pulmonary leukocyte sequestration in man during hemodialysis with different membrane-types.

Although it has been suggested that pulmonary sequestration of leukocytes could account for membrane-dependent white blood cell depletion in HD, direct evidence in patients is still lacking. Therefore a study was initiated to test whether and how leukocytes distribute in the lung circulation during HD with different membranes. Thirteen patients suffering from chronic renal failure underwent lung scintigraphy during HD with cuprophane (n = 3), hemophane (n = 8) and polysulfone (n = 2) lowflux capillary dialyzers. Isolated autologous leukocytes were labelled with 99m-Technetium and reinfused before starting HD. Distribution of leukocyte related activity was registered by lung scintigraphy. In comparison to normal lung scintigraphy performed without HD, an impressive redistribution peak was demonstrated 10-20 min after the start of HD with cuprophane and also to a lesser extent with hemophane. When HD was performed with polysulfone the decrease in activity was delayed but no real redistribution was obtained. In accordance with other phenomena, such as peripheral leukopenia and changes in granulocyte oxidative metabolism, pulmonary sequestration of leukocytes takes place in man in the initial phase of HD and appears to be strongly dependent on the type of membrane.

Humans↗
PubMed1990

[99mTc-2-methoxy-isobutyl-isonitrile in the diagnosis of coronary heart disease: results of a multicenter study].

A total of 226 patients was studied in a phase-III multicenter trial to compare the results of stress/rest 99mTc-MIBI with 201TI scintigraphy and/or coronary arteriography. The evaluation of planar and SPECT imaging was based on a semiquantitative visual scoring. A congruent diagnosis was generated from all planar 201TI and 99mTc-MIBI scintigrams performed in 36 patients. In 62 of 63 patients, SPECT-studies with 99mTc-MIBI and 201TI led to an identical diagnosis. In one patient a positive result was obtained with 201TI-SPECT whereas 99mTc-MIBI was negative. Segmental agreement for 1509 SPECT segments was 85.7%, for 554 planar segments it was 86.6%. In comparison to coronary arteriography, performed in 180 patients, the overall sensitivity for the correct diagnosis of coronary artery disease (CAD) was 86% for planar MIBI scintigraphy or 92% for MIBI-SPECT. Overall specificity was 100% for planar imaging and 57% for SPECT. The low specificity of MIBI-SPECT was probably due to high prevalence of CAD in this study population. In a subgroup of 43 patients, who underwent coronary angiography, identical results were found with 99mTc-MIBI and 201TI. Only one patient showed a positive scintigraphic result with both 99mTc-MIBI and 201TI without angiographically proven stenosis greater than 50% or prior myocardial infarction. Vessel sensitivities in stenosed coronary arteries (greater than 50% stenosis) were 54% for the LAD and 87% for the RCX/RCA areas with MIBI-SPECT, or 51% or 79% for planar scintigraphy, respectively. Vessel specificities for SPECT were 65% in the LAD or 52% in the RCX/RCA, or 90% or 83% in planar imaging.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗