Degradation pathways for recombinant human macrophage colony-stimulating factor in aqueous solution.

Recombinant human macrophage colony-stimulating factor (rhM-CSF) promotes macrophage proliferation and activity. rhM-CSF clinical trials are currently in progress and require a stable, pharmaceutically acceptable dosage form. This report documents pH effects on rhM-CSF degradation profiles in aqueous solution, with an emphasis on identifying degradation products. Thus, highly purified rhM-CSF was maintained at 30 to 50 degrees C in solutions adjusted to pH 2 to 10. Stressed samples were analyzed by SDS-PAGE, reverse-phase HPLC, size exclusion HPLC, scanning microcalorimetry, and murine bone marrow activity. The results show maximal protein stability in the region pH 7 to 8. Degradation product chromatographic and electrophoretic analyses show distinctly different degradation product profiles in acidic versus alkaline solution. For samples stressed in acidic solution, degradation products were isolated chromatographically and electrophoretically. These degradation products were characterized by N-terminal amino acid sequencing, fast-atom bombardment mass spectrometry, and peptide mapping. The results show that the major degradation pathway in acidic solution involves peptide cleavage at two sites: aspartate169-proline170 and aspartate213-proline214. A third potential cleavage site (aspartate45-proline46) remains intact under conditions that cleave Asp169-Pro170 and Asp213-Pro214. In alkaline solution, degradation proceeds via parallel cleavage and intramolecular cross-linking reactions. A beta-elimination mechanism is proposed to account for the degradation in alkaline solution. Consistent with literature observations, the rhM-CSF N-terminal cleavage products retain biological activity.

Vapor heat treatment for zucchini infested with Bactrocera cucumis (Diptera: Tephritidae).

Zucchini, Cucurbita pepo L., infested with 22-h-old eggs of Bactrocera cucumis (French) were completely disinfested using a vapor heat treatment of 45 degrees C with > 94% RH for 30 min. An estimated total of 178,219 eggs (22 h old) was treated without survivors, thus achieving probit 9 mortality. Twenty-two-h-old eggs were significantly more tolerant of heat than first, second, or third instars. All treatments were done in a Sanshu model EHK-1000B vapor heat treatment system.

The liver scan in urologic oncology.

The predictive value of liver scans for the detection of hepatic metastases is discussed. A retrospective review was done on 104 patients with urologic malignancies who had undergone liver scans and liver function tests. Liver scans had a low predictive value, while serum alkaline phosphatase alone had a higher predictive value. The combination of low predictive value and high cost/benefit ratio indicates that the liver scan has no routine role in the urologic oncologic staging.

Interaction of tritium-labeled H2DIDS (4,4'-diisothiocyano-1,2,diphenyl ethane-2,2'disulfonic acid) with the Ehrlich mouse ascites tumor cell.

The experiments reported in this paper were undertaken to explore the interaction of tritiated H2DIDS (4,4'-diisothiocyano-1,2,diphenyl ethane-2,2'-disulfonic acid) with Ehrlich ascites tumor cells. Addition of (3H)H2DIDS to tumor cell suspension at 21 degrees C, pH 7.3, resulted in: (i) rapid reversible binding which increased with time and (ii) inhibition of sulfate transport. Tightly bound H2DIDS i.e., reagent not removed by cell washing, also increased with time. Binding of 0.02 nmol H2DIDS/mg dry mass or less did not affect sulfate transport, but, at greater than 0.02 nmol and up to 0.15 nmol the relationship between tight binding and inhibition of transport is linear. The fact that H2DIDS could bind to the cell and yet not affect anion transport suggests that binding sites exist unrelated to those concerned with the regulation of anion permeability. Support for this is the observation that H2DIDS is spontaneously released from cells even after extensive washings by a temperature-sensitive process. The most important source of released H2DIDS is the cell surface coat which labels rapidly (within 1 min) and is then spontaneously released into the medium. A second source is derived from H2DIDS that slowly entered the cells. Consequently, at least four modes of interaction exist between H2DIDS and ascites tumor cells. These include both reversible and irreversible binding to membrane components which regulate anion permeability, irreversible binding to cell surface proteins or glycocalyx, and finally incorporation of H2DIDS into the intracellular phase.

Discordant imaging of a thyroid nodule with 131I and 99mTc: concordance of 131I and fluorescent scans.

A thyroid nodule, "hot" by 99mTc and "cold" by 131I scanning, was reimaged with a fluorescent scanner. The fluorescent scan was qualitatively similar to the 131I scan and demonstrated low iodine content in the nodule. This combination of scan patterns is compatible with an organification defect in the nodular tissue.

Quantitative thyroid fluorescent scanning: technique and clinical experience.

A method for quantifying thyroid gland iodine content using a modified fluorescence scanning system is described. The technique does not require a computer. Two single channel analyzers and digital scalers are used to determine net counts from iodine k-alpha x-rays and system response in counts per milligram is calibrated from studies of known quantities of iodine placed in thyroid phantoms. Fluorescence quantification of thyroid gland iodine content was performed in 250 patients with a wide variety of thyroid disorders. Thirty euthyroid patients judged to have no evidence of thyroid disease averaged 10.1 +/- 3.9 mg glandular iodine. Results for several major diagnostic categories were: untreated Graves' disease, 28 patients, 24.4 +/- 9.9 mg; diffuse euthyroid goiter, 14 patients, 16.1 +/- 7.4 mg; primary hypothyroidism, seven patients, 0.5 mg; and nontoxic multinodular goiter, 28 patients, 7.3 +/- 4.1 mg. Follow-up studies on patients treated for Graves' disease both medically and with 131I generally revealed elevated iodine contents in persistently hyperthyroid patients, lower than normal average amounts in euthyroid patients, and only trace amounts in hypothyroid patients. Although the clinical role of fluorescence iodine quantification remains to be fully established, the technique provides information not otherwise available on an important parameter of thyroid status.

Solitary autonomous thyroid nodules: comparison of fluorescent and pertechnetate imaging.

Twelve patients with solitary autonomous thyroid nodules were scanned with [99mTc] pertechnetate and by fluorescent imaging. Nodular dimensions were essentially identical on the two types of scans, but the relative scan densities in the nodular versus extranodular areas demonstrated striking differences. In 11 of the 12 patients, the ratio of nodular-to-extranodular radiotracer accumulation was significantly higher than the ratio of nodular-to-extranodular iodine content. In two patients with no demonstrable extranodular radiotracer accumulation by initial pertechnetate scan, extra-nodular tissue was demonstrated by fluorescent imaging. In such cases, fluorescent scanning may eliminate the need for a second radionuclide scan following TSH stimulation to visualize the extranodular tissue. Fluorescent scanning offers a unique new method for aiding the evaluation of patients with suspected autonomous nodules, and can facilitate the diagnosis in some cases. The maintenance of relatively uniform iodine concentration between nodular and extranodular tissues is an intriguing finding that bears further investigation.

Evaluation of a thyroid fluorescent scanning system of concentric source-detector design.

A concentric source-detector system for thyroid fluorescent scanning is described, including fundamental parameters of system response and adaptation of a conventional rectilinear scanner for use with it. The basic system consists of twenty 1-Ci sources of 241Am, a 500-mm2 Si(Li) detector, and associated pulse-height electronics. The image-forming equipment of the rectilinear scanner is retained. We have developed a clinical imaging technique that provides a photon density of 600-800 counts/cm2 over the thyroid gland in subjects with normal iodine pools. Comparisons are made between the outrigger design for fluorescent scanning and conventional emission scanning.

Solitary abnormalities in bone scans of patients with extraosseous malignancies.

The incidence and significance of solitary bone scan abnormalities were assessed in a study of 1,129 consecutive patients with extraskeletal primary malignancies. Solitary abnormalities were encountered in 172 cases (15%). The etiology of the scan abnormality was established in 90 of the 172 cases; 58 (64%) were due to metastatic disease, and 32 (36%) were secondary to a benign process. A significant percentage of solitary scan abnormalities is due to benign disease processes, even in patients with proved extraosseous malignancies.

Body-background defects with 99mTc-DTPA after renal transplantation: case reports.

Photon-deficient areas adjacent to transplanted kidneys were seen in the early phases of several dynamic studies obtained with 99mTc-diethylenetri-aminepentaacetic acid (99mTc-DTPA). The causes included hematoma, urinoma, and lymphocele. These fluid collections do not readily exchange as part of the extracellular space and, if sufficiently large, may be visualized as photon-deficient areas in the normally homogeneous background of 99mTc-DTPA studies.