Strongly correlated superconductivity in a copper-based metal-organic framework with a perfect kagome lattice.

Metal-organic frameworks (MOFs), which are self-assemblies of metal ions and organic ligands, provide a tunable platform to search a new state of matter. A two-dimensional (2D) perfect kagome lattice, whose geometrical frustration is a key to realizing quantum spin liquids, has been formed in the π - d conjugated 2D MOF [Cu3(C6S6)] n (Cu-BHT). The recent discovery of its superconductivity with a critical temperature T c of 0.25 kelvin raises fundamental questions about the nature of electron pairing. Here, we show that Cu-BHT is a strongly correlated unconventional superconductor with extremely low superfluid density. A nonexponential temperature dependence of superfluid density is observed, indicating the possible presence of superconducting gap nodes. The magnitude of superfluid density is much smaller than those in conventional superconductors and follows the Uemura's relation of strongly correlated superconductors. These results imply that the unconventional superconductivity in Cu-BHT originates from electron correlations related to spin fluctuations of kagome lattice.

5-fs, Multi-mJ, CEP-locked parametric chirped-pulse amplifier pumped by a 450-nm source at 1 kHz.

We report on the development of an optical parametric chirpedpulse amplifier at a 1-kHz repetition rate with a 5.5-fs pulse duration, a 2.7-mJ pulse energy and carrier-envelope phase-control. The amplifier is pumped by a 450-nm pulse from a frequency-doubled Ti:sapphire laser.

Estimation of thyroxine and triiodothyronine distribution and of the conversion rate of thyroxine to triiodothyronine in man.

Studies on peripheral metabolism of simultaneously administered 125-I-labeled L-thyroxine ([125-I]T4) and 131-I labeled L-trilodothyronine ([131-I]T3) were performed in five normal subjects, in four patients with untreated hypothyroidism, and in 3 hypothyroid patients made euthyroid by the administration of T4. The fractional turnover rate (lambda 03) of thyroid hormones irreversibly leaving the site of degradation and the volumes of pool 1 (serum V1) of pool (interstitial fluid, V2), and of pool 3 (all tissues, V3)were obtained by using a three-compartment analysis. In addition to the turnover studies, the ratios for the in vivo T4 to T3 conversion were determined by paper chromatographic study in sera obtained 4, 7, and 10 daysafter the injection. The rate (K12) of the extrathyroidal conversion of T4 to T3 was also estimated by the compartment analysis. The T3 distribution volume (V3) of pool 3, in which T3 is utilized and degraded, was about 60% of totaldistribution volume (V=V1+V2+V3) in normal subjects, whereas only about 25% of the extrathyroidal T4 pool was in the intracellular compartment, indicating that T3 is predominantly an intracellular hormone..

Recognition of ovarian cancer antigen CA125 by murine monoclonal antibody produced by immunization of lung cancer cells.

In studies aimed at developing monoclonal antibodies against lung adenocarcinomas, we produced a murine monoclonal antibody designated 130-22 by immunizing mice with lung cancer cells. Since in immunoperoxidase staining experiments this antibody was reactive not only with lung adenocarcinomas but also with ovarian carcinomas, we examined its relationship to the ovarian cancer marker CA125, an antigen recognized by monoclonal antibody OC125 produced by immunization of mice with ovarian carcinoma cells. Although CA125 antigen was adsorbed by 130-22 antibody, 125I-labeled 130-22 did not compete with OC125, indicating that although these two antibodies recognized CA125 antigen, they reacted with separate antigenic determinants. The antigen defined by both antibodies was thought to be heat-labile glycoprotein with a molecular weight of over 1,000,000. A series of immunoradiometric assays was developed using combinations of two monoclonal antibodies in a simultaneous forward sandwich mode. Mixed monoclonal antibodies may provide a more sensitive assay for the detection of CA125 than the homologous assay, in which OC125 was used both as a tracer and as a catcher. These results indicate that CA125 is an antigen with two separate epitopes present in both ovarian and lung adenocarcinomas and that combination use of monoclonal antibodies reactive with different antigenic determinants will give certain advantages to the immunoradiometric assay of cancer markers.

Effect of AA861, a 5-lipoxygenase inhibitor, on amylase secretion from rat pancreatic acini.

We have examined the effects of 2,3,5-trimethyl-6-(12-hydroxy-5,10-dodecadiynyl)-1,4-benzoquinone (AA861), a selective inhibitor of 5-lipoxygenase, on the action of cholecystokinin (CCK) and other secretagogues in the stimulation of amylase secretion from dispersed rat pancreatic acini. AA861 inhibited amylase secretion caused by CCK, carbamylcholine (carbachol), bombesin or calcium ionophore A23187 but failed to affect amylase secretion by vasoactive intestinal peptide or 12-O-tetradecanoyl-phorbol 13-acetate. Inhibition by AA861 of CCK or carbachol-induced amylase secretion was confined to the relatively lower concentrations of these secretagogues. AA861 did not inhibit receptor binding of CCK or alter the cellular calcium mobilization induced by CCK. In kinetic studies, AA861 was effective only on amylase secretion from pancreatic acini incubated with CCK for more than 5 min. Indomethacin, a known inhibitor of cyclooxygenase, did not affect the amylase secretion caused by all secretagogues used. These results indicate that the 5-lipoxygenase pathway of arachidonate metabolism may be involved in the actions of calcium-dependent secretagogues of amylase secretion in rat dispersed pancreatic acini, especially for sustaining stimulation of amylase secretion by CCK.

Stress thallium-201 transaxial emission computed tomography: quantitative versus qualitative analysis for evaluation of coronary artery disease.

Stress thallium-201 myocardial distribution was quantitatively evaluated by emission transaxial tomography in 104 patients who underwent coronary arteriography. The initial uptake and percent washout of thallium were assessed by the circumferential profile curves of the three short-axis sections and one middle right anterior oblique long-axis section. This quantitative tomographic analysis showed abnormal distribution in all but two patients (98%) with coronary artery disease, whereas qualitative analysis showed abnormality in 76 of the patients (93%). Quantitative analysis showed better sensitivity (91%) for detecting involved coronary vessels than qualitative analysis (80%, p less than 0.01), especially in three vessel disease (82 versus 67%, p less than 0.05). For localization of individual vessel involvement, quantitative analysis showed high sensitivity (right coronary artery: 96%, left anterior descending artery: 90% and left circumflex artery: 88%) as compared with qualitative analysis (88, 83 and 63%, respectively, p less than 0.05), while similar specificity was observed (92% for quantitative and 93% for qualitative analyses). Furthermore, in the study of patients without infarction, myocardial segments supplied by coronary vessels with moderate stenosis (51 to 75%) revealed abnormality more often with quantitative (81%) than with qualitative (56%) analysis. Thus, quantitative analysis of stress thallium emission tomography provides improved sensitivity for the detection of diseased coronary vessels in patients with three vessel disease and those with moderate stenosis. It is a valuable technique for the evaluation of coronary artery disease.

Adenylate cyclase activation and competitive binding with renal tissue using synthetic eel calcitonin analog and its fragments.

The structure-function relationship of calcitonin (CT) was investigated using a synthetic eel CT (E-CT) analog and its fragments. Adenylate cyclase activation and competitive binding to rat renal receptors were used as parameters of function. [Asu1,7]E-CT analog, synthesized by replacing the S-S bond of Cys1-Cys7 in the natural hormone with ethylene linkage of 1-amino suberic acid (Asu), and E-CT fragment 11-32 had about 1/5th and 1/50th the potencies of synthetic E-CT, respectively, in both adenylate cyclase activation and competitive inhibition of 125I-labeled [Asu1,7]iodo-E-CT binding on rat renal plasma membranes. The minimal chain length required to activate adenylate cyclase in rat renal plasma membranes was between 12-18 amino acids, and the minimal chain length required to affect the CT receptor binding was between 6-12 amino acids, near the C-terminus. Fragments, including the C-terminus, show a disproportionate and potent inhibition of the binding compared with the potency required for adenylate cyclase activation. Thus, the amino acid sequence near the C-terminus probably plays an important role in the binding of CT to the receptor. (Endocrinology 108: 698, 1981.)

A new in vitro assay for human thyroid stimulator using cultured thyroid cells: effect of sodium chloride on adenosine 3',5'-monophosphate increase.

A new sensitive in vitro assay for human thyroid stimulator (HTS) was developed using human thyroid adenoma cells in monolayer culture. After being cultured for 2 days, the cells were incubated in 0.3 ml Hank's solution without 0.8% NaCl (medium 1) and with thyroid stimulator (bovine TSH or 3 mg patient serum immunoglobulin G) at 37 C for 2 h. The cAMP generated in the cells and the medium during the incubation was measured by RIA. The assay was sensitive enough to elicit a 1.7- to 7.9-fold increase in cAMP at a TSH concentration of 10 microU/ml. HTS was detected in 33 (82.5%) of the 40 patients with untreated graves' disease using this assay system. In Hank's solution (medium 2), however, HTS was detected in only 5 (23.8%) of the 21 patients with untreated GRaves' disease. cAMP increment upon stimulation by either TSH or HTS in medium 1 was larger than that in medium 2, and the difference in the response to HTS using the two media was much greater than that in the response to TSH. Therefore, all HTS-immunoglobulin G studies showed higher activity using medium 1 than using medium 2 when expressed as bovine TSH equivalent. Analysis by the Lineweaver-Burk plot of dose-response curves of the effect of TSH and HTS stimulation on cAMP increment showed an increase in the Km upon the addition of NaCl to the medium. A similar inhibitory effect of NaCl (150 mM) was also observed in the assay system of human thyroid adenylate cyclase stimulator using crude plasma membrane fractions. In summary: 1) an assay for HTS measuring cAMP production in cultured thyroid adenoma cells was developed and the assay using low NaCL medium was found to be the most sensitive, and 2) the inhibitory effect of NaCl on the response to HTS was much greater than that on the response to TSH. These data suggest different behaviors of these two stimulators at their receptor sites.

A sensitive and practical assay for thyroid-stimulating antibodies using crude immunoglobulin fractions precipitated with polyethylene glycol.

A simple, sensitive, and practical assay for thyroid-stimulating autoantibodies (TSAb) was developed in which cryopreserved porcine thyroid cells were incubated with crude immunoglobulin fractions sedimented from serum with polyethylene glycol. In the assay, 1.4- to 2.0-fold and 6- to 12-fold increases in cAMP released into Hank's medium without NaCl were found at 1 and 10 microU/ml bovine TSH, respectively. TSAb were detected in 41 (97.6%) of 42 patients with untreated hyperthyroid Graves' disease, 29 (55.8%) of 52 patients with hyperthyroid Graves' disease who were euthyroid while taking antithyroid drugs, 22 (78.6%) of 28 patients with euthyroid Graves' disease, and none of the patients with simple goiter, adenomatous goiter, thyroid adenoma, or thyroid cancer tested. TSAb activities measured using porcine thyroid cells significantly correlated with those measured using human thyroid adenoma cells (r = 0.908; n = 46; P less than 0.001). Thyroid-stimulating activity was also detected in 11 (28.9%) of 38 patients with Hashimoto's thyroiditis. However, the activity was considered to be due to TSH in the patients' sera, because it was completely abolished by pretreatment with anti-TSH antibodies. Serum TSH concentrations lower than 50 microU/ml did not affect the assay result. In Graves' disease after cessation of antithyroid drugs, 85.7% (12 of 14) of TSAb-positive patients relapsed, while 77.8% (14 of 18) of TSAb-negative patients remained in remission. Thus, the assessment of TSAb was useful as an index to predict prognosis.

Detection and properties of TSH-binding inhibitor immunoglobulins in patients with Graves' disease and Hashimoto's thyroiditis.

TSH-binding inhibitor immunoglobulins (TBII) have been detected in patients with Graves' disease and Hashimoto's thyroiditis by using the radioreceptor assay of TSH. In untreated Graves' patients, TBII levels correlated well with thyroidal 99mTc uptake at 30 min and the grade of epithelial hyperplasia of thyroid follicles. There were many Graves' patients whose sera contained high TBII levels but no detectable bioassayable thyroid-stimulating activity (LATS), and in these patients, close correlation was observed between serum levels of TBII and bioassayable LATS-protector activity. TBII were detectable in 2 (10%) of 20 patients with Hashimoto's thyroiditis, both of whom were clinically hypothyroid. The serum or IgG fraction from one of them, however, did not contain any significant LATS, LATS-protector, or human thyroid adenylate cyclase-stimulating activity and caused inhibition of adenylate cyclase stimulation by TSH. In that patient, TBII may be acting to block TSH binding to TSH receptors, thus causing TSH unresponsiveness and hypothyroidism.

Inhibition of thyrotropin-induced adenosine 3'5'-monophosphate increase by immunoglobulins from patients with primary myxedema.

Immunoglobulin G (IgG) fractions prepared from the serum of 18 patients with primary myxedema, 9 patients with goitrous Hashimoto's thyroiditis, and 14 normal controls were tested for their ability to alter TSH stimulation of cAMP production in cultured human thyroid cells and the binding of TSH to its receptor. When compared with the cAMP increase induced by 0.1 mU/ml bovine TSH in the presence of normal IgG, cAMP accumulation was significantly inhibited (P less than 0.005) by the addition of IgG from patients with primary myxedema. TSH-induced cAMP accumulation was not affected by IgG from patients with goitrous thyroiditis. IgG from patients with primary myxedema also inhibited the cAMP increase induced by thyroid-stimulating immunoglobulins, but not against the increase induced by prostaglandin E1. None of the IgG tested affected the basal level of cAMP. Two potent inhibitory IgG were strongly positive for TSH-binding inhibitor immunoglobulins. Excluding these, no significant correlation was found between the thyroid stimulation-blocking activity and the TSH-binding inhibitory activity. These data suggest the presence of at least two different types of antibodies in primary myxedema which block adenylate cyclase stimulation by TSH and might be responsible for thyroid dysfunction and atrophy.

Inhibition of thyrotropin-induced growth of rat thyroid cells, FRTL-5, by immunoglobulin G from patients with primary myxedema.

We studied thyroid growth-blocking activity in immunoglobulin G (IgG) fractions of serum from 24 patients with primary myxedema, 24 patients with goitrous Hashimoto's thyroiditis, and 18 normal subjects by measuring the ability of their IgG to inhibit TSH-induced [3H]thymidine incorporation into DNA in a rat thyroid cell line, FRTL-5. Both groups of patients were receiving T4 when studied. [3H]Thymidine incorporation induced by 0.1 mU/ml bovine TSH was significantly inhibited by the addition of 2 mg/ml IgG from patients with primary myxedema (P less than 0.01), while it was not affected by IgG from the normal subjects or 23 of the 24 patients with goitrous Hashimoto's thyroiditis. IgG from patients with primary myxedema also inhibited the [3H]thymidine incorporation induced by Graves' IgG, but not that induced by forskolin, cholera toxin, (Bu)2cAMP or phorbol-12-myristate-13-acetate. The inhibition of TSH-induced [3H]thymidine incorporation by IgGs from patients with primary myxedema was significantly correlated with their inhibitory activities against both TSH-induced cAMP generation and TSH binding (P less than 0.001). These data indicate that these growth-blocking antibodies are directed against the TSH receptor and might be one of the causes of the thyroid atrophy in patients with primary myxedema.

Circulating 1,25-dihydroxyvitamin D concentrations in patients with renal cell carcinoma-associated hypercalcemia are rarely suppressed.

We measured serum 1,25-dihydroxyvitamin D concentrations in 18 patients with renal cell carcinoma-associated hypercalcemia. Only 2 patients (11%) had low serum 1,25-dihydroxyvitamin D (less than 15 pg/ml) levels, and the mean 1,25-dihydroxyvitamin D level in the 18 patients was 44 +/- 30 (+/- SD) pg/ml, not different from the value of 42 +/- 22 pg/ml in 75 age-matched normocalcemic patients with various malignancies. Eighty-seven percent (26 of 30) of the hypercalcemic patients with extensive skeletal metastases due to other malignancies or with hematological malignancies had suppressed serum 1,25-dihydroxyvitamin D levels (less than 15 pg/ml). In hypercalcemic patients with other malignancies and no skeletal metastases, only 54% (21 of 39) had low serum 1,25-dihydroxyvitamin D levels. The mean serum 1,25-dihydroxyvitamin D level in the latter group was 21 +/- 26 pg/ml, significantly lower than that in normocalcemic patients. In renal cell carcinoma-associated hypercalcemia, suppression of circulating 1,25-dihydroxyvitamin D concentrations is uncommon.

Identification of 1,24(R)-dihydroxyvitamin D3-like bone-resorbing lipid in a patient with cancer-associated hypercalcemia.

A lipid indistinguishable from 1,24(R)-dihydroxyvitamin D3 [1,24(R)-(OH)2D3] was found in serum and tumor extracts from a hypercalcemic patient with a small cell carcinoma of the lung. The lipid comigrated with authentic 1,24(R)-(OH)2D3 on high performance liquid chromatography using both straight and reverse phase columns and competed with tritiated 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3)] for binding to intestinal 1,25-(OH)2D3 receptor. Increasing doses of the lipid factor from tumor and authentic 1,24(R)-(OH)2D3 gave parallel responses in a bone resorption assay, as assessed by 45Ca release from prelabeled mouse calvaria. The lipid factor from the patient's serum and authentic 1,24(R)-(OH)2D3 had identical biological activities in the receptor binding and bone resorption assays. In addition, the mechanisms of action of this lipid factor and 1,24(R)-(OH)2D3 were indistinguishable. Bone resorption by both was inhibited by calcitonin, and neither the lipid factor nor authentic 1,24(R)-(OH)2D3 affected cAMP content in osteoblast-like bone cells derived from mouse calvaria. The estimated concentrations of the 1,24(R)-(OH)2D3-like lipid, expressed as 1,24(R)-(OH)2D3 were 11 ng/g tumor wet wt by the receptor binding assay and 9.2 ng/g tumor wet wt by the bone resorption assay. The mean serum concentration was 1.4 +/- 0.3 (+/- SD) ng/ml (n = 3) by the receptor binding assay. No activity was detected in either bioassay when extracts of nontumor tissues from this patient or tumor extracts and sera from one hypercalcemic and four normocalcemic cancer patients were tested. The mean serum 1,25-(OH)2D level was low (6.4 +/- 0.5 pg/ml; n = 2), and serum 1,24(R),25-(OH)3D in this patient was high (103 pg/ml) compared to normocalcemic cancer patients, in whom the mean serum 1,25-(OH)2D level was 27 +/- 12 pg/ml (n = 4) and the 1,24(R),25(OH)3D level was 28 +/- 1.3 pg/ml (n = 4). Thus, the 1,24(R)-(OH)2D3-like lipid may be a substrate for metabolic conversion to 1,24(R),25-(OH)3D in vivo. These results provide evidence for the presence of a novel metabolite of vitamin D3, 1,24(R)-(OH)2D3. Detection of this bone-resorbing lipid in both tumor and serum suggests, but does not prove, that the tumor secreted this bioactive lipid into the circulation and that the high level of circulating bone-resorbing lipid was related to the hypercalcemia in this patient.

Tumor imaging after administration of 99mTc-labeled bleomycin.

Bleomycin, an anticancer drug, was labeled with 99mTc using stannous chloride and ascorbic acid and specific activities of 1-3 mCi/mg-eq with labeling efficiencies of 50-75% were achieved. Very rapid excretion of 99mTc-bleomycin through the kidney and concomitant rapid decrease of radioactivity in blood, various tissues and organs, and whole body were observed after intravenous administration of the radiopharmaceutical into tumor-bearing mice. In such animals, approximately 1% of the label was found in a transplanted fibrosarcoma within 30 min while 0.58% was recovered in such lesions even after 24 hr. In patients positive tumor images were obtained by scintigraphy as early as 1 hr after intravenous administration of 3-5 mCi of 99mTc-bleomycin. A total of 142 cases were examined by scintigraphy after administration of 99mIc-bleomycin and/or 67Ga-citrate. In 93 cases with various malignant tumors, tumor was detected in 80% using 99mTc-bleomycin and in 63% using 67Ga-citrate. Technetium-99m-bleomycin scintigraphy successfully detected tumors of the thyroid, lung, face, breast, extremity, and digestive tract and was also useful in finding metastatic lesions and brain tumors. However, 67Ga scintigraphy gave superior results in detecting lesions in patients with malignant lymphomas. In patients with inflammatory diseases, accumulation in lesions was detected in 13% using 99mTc-bleomycin and in 48% using 67Ga-citrate. The further use of 99mTc-bleomycin scintigraphy for tumor detection in patients appears to be warranted.

Quantitative evaluation of regional pulmonary ventilation using PET and nitrogen-13 gas.

A new quantitative method, "Simultaneous Exponential Equation method" (SEE), has been developed for the analysis of pulmonary ventilation studies using 13N-labeled nitrogen gas and positron emission computed tomography. This method uses Kety's model assuming insolubility of nitrogen gas in blood or tissues. Activity in poorly ventilated regions does not reach the equilibrium in the so-called equilibrium scan (EQ) performed following 3 or 4 min of washin. Therefore EQ images do not represent lung volume images nor do they provide the initial value of washout phase. Our method corrects for these transient phenomena observed during EQ scan and yields idealistic equilibrium state images (lung volume images) as well as more accurate regional ventilatory time constants than a modified Stewart-Hamilton (A/H) method and tomograms of high resolution.

Functional imaging of intrarenal blood flow using scintillation camera and computer.

In order to obtain spatial distribution of an index for regional blood flow at each element on a scintigraphic image of the kidney, we attempted the construction of the so-called functional image. After injecting a single bolus of 133Xe into a renal artery by means of a catheter, this objective was accomplished using digital computer processing for a sequence of scintillation camera recordings of the following washout process from the kidney. This is expressed in a form of matrix of disappearance rate constant. Calculation for the rate constant, the flow index of the functional image, was done using either the least squares (LS) method or height-over-area (H/A) method. Although the former method was considered to be theoretically suitable without undue participation of background activities, the latter was preferred because of stable results for image construction. On reviewing the functional image thus obtained from 22 patients representing a variety of renal diseases, the H/A gave specific information concerning regional distribution of the perfusion integrity mainly related to the cortical part of the kidney. This is often difficult to accomplish utilizing the conventional method of compartmental analysis of the xenon washout curve or selective renal angiography.

Quantitative assessment of ventilation-perfusion mismatch by radioxenon imaging of the lung.

By the use of xenon-133 and a scintillation camera with digital data storage and processing system, a topographic relationship between ventilation distribution (V) and perfusion distribution (Q) was examined quantitatively in two groups of normal nonsmokers and one of older smokers, all healthy. In addition, subjects with a variety of cardiopulmonary disease were tested. The fractional regional ventilation (VR) and regional perfusion (QR) were plotted against the V/Q ratio on a logarithmic abscissa for the normal subjects; both were distributed log-normally with a narrow standard deviation, and were dissociated slightly from each other. However, with smoking and with increasing age, the s.d. and the dissociation became wider, suggesting an impairment of gas exchange as estimated by alveolar-atrial gas-pressure differences (A-aD), which were calculated by putting these topographic relationships into a gas-exchange program in a computer. In various cardiopulmonary diseases a good correlation was found between the estimated A-aDO2 thus obtained and the actual A-aDO2 derived from analysis of the blood gases.

Clinical evaluation of thallium-201 emission myocardial tomography using a rotating gamma camera: comparison with seven-pinhole tomography.

Single-photon emission computed tomography (SPECT) for thallium-201 myocardial imaging with a rotating gamma camera was evaluated in comparison with planar imaging and seven-pinhole tomography (7P). Cardiac phantom studies indicated that defects 2 cm in diameter can be visualized by both tomographic methods, but the 7P method showed propagation of the image into nearby planes, with lower image contrast. In a clinical study of 47 patients with myocardial infarction, both sensitivity and specificity for the SPECT system were high (96 and 89%, respectively); the 7P system, on the other hand, showed good sensitivity (93%) but poor specificity (68%), while planar imaging performed conversely (75 against 89%). The overall accuracy was not significantly improved in the 7P method (planar: 81%, 7P: 83%, and SPECT: 94%). Our study indicates that SPECT, which can reconstruct reliable tomographic sections in either the transaxial, frontal, or sagittal planes, will result in a remarkable improvement in the clinical evaluation of ischemic heart disease.

Deferoxamine, a promising bifunctional chelating agent for labeling proteins with gallium: Ga-67 DF-HSA: concise communication.

A new efficient method has been developed for the labeling of various biologically important proteins with radiogallium, using deferoxamine (DF) as a bifunctional chelating agent. Human serum albumin (HSA) was chosen for studying the DF coupling reaction by a glutaraldehyde two-step method. The DF-HSA conjugate obtained was then easily labeled with Ga-67 with high efficiency and reproducibility. High stability of the Ga-67 DF-HSA was observed both in vitro and in vivo. In rats the half-time of blood clearance at the first phase was 234 min for the Ga-67 DF-HSA, whereas most conventional I-131 HSA gives 121 min. The excellent pharmacological and physiological properties were assessed by plasma clearance and plasma volume measurements in normal volunteers. Even at 2 hr after injection, (90.0 +/- 3.0)% of Ga-67 DF-HSA was retained within the vascular space. The mean plasma volume per kilogram of body weight, measured with Ga-67 DF-HSA, was 46.6 +/- 3.4 ml/kg, compared with 52.2 +/- 2.4 ml/kg as determined with I-131 HSA in the same men.