A galactomannan from Crotalaria medicaginea seeds.

A polysaccharide isolated from the seeds of Crotalaria medicaginea is composed of D-galactose and D-mannose in the molar ratio of 10:31. Structural studies were performed by methylation analysis, partial acid hydrolysis, chromic oxide oxidation, mild hydrolysis with dilute oxalic acid and 13CNMR analysis of the polymer.

Growth regulation of mouse mammary tumor cells in collagen gel cultures by diffusible factors produced by normal mammary gland epithelium and stromal fibroblasts.

We have reported previously that both normal mammary epithelium and stroma stimulate the growth of mouse mammary tumors in vivo. We have devised a method to investigate the role of diffusible factors in these growth interactions in vitro. Because an appropriate matrix, a particular cell shape, or multicellular organization may be required for the production of factors and/or for the response to such factors, the method assesses the expansion of boluses of cells in collagen gel matrix.

Characterization of the flavoprotein moieties of NADPH-sulfite reductase from Salmonella typhimurium and Escherichia coli. Physicochemical and catalytic properties, amino acid sequence deduced from DNA sequence of cysJ, and comparison with NADPH-cytochrome P-450 reductase.

NADPH-sulfite reductase flavoprotein (SiR-FP) was purified from a Salmonella typhimurium cysG strain that does not synthesize the hemoprotein component of the sulfite reductase holoenzyme. cysJ, which codes for SiR-FP, was cloned from S. typhimurium LT7 and Escherichia coli B, and both genes were sequenced.

Characterization of the cysJIH regions of Salmonella typhimurium and Escherichia coli B. DNA sequences of cysI and cysH and a model for the siroheme-Fe4S4 active center of sulfite reductase hemoprotein based on amino acid homology with spinach nitrite reductase.

The hemoprotein component of Salmonella typhimurium sulfite reductase (NADPH) (EC 1.8.1.

Regulation of phosphatidylcholine biosynthesis in activated alveolar type II cells.

The biosynthesis of phosphatidylcholine was studied in a population of activated Type II cells isolated from the lungs of rats treated with silica. Type II cells were separated by centrifugal elutriation into two populations, designated Type IIA and Type IIB. The Type IIB or activated population consisted of Type II cells that were larger than normal cells; Type IIA cells were morphologically similar to normal Type II cells.

Therapeutic perturbation of the tumor ecosystem in reconstructed heterogeneous mouse mammary tumors.

We have measured the response to methotrexate in vivo of paired mixtures of sister subpopulation lines from a mouse mammary tumor, as a model of drug response of a heterogeneous tumor. The subpopulation lines differed in intrinsic sensitivity to methotrexate. Response was measured both as growth delay and as a shift in tumor cell population distribution toward the more resistant cell line.

Therapeutic implications of tumor heterogeneity.

At the outset of this review, we stated that we wished to raise some questions that challenge the commonly held view that tumor heterogeneity is of major significance to treatment failure. The nature of this challenge is the following: although tumor heterogeneity in sensitivity to therapeutic agents has been demonstrated repeatedly, using isolated subpopulations of cells, primarily in cell culture systems, there is very little work that has been directed toward asking the tough questions about how that heterogeneity actually impacts on the response to treatment in vivo. In our own work, when we have attempted to simulate heterogeneity, in vivo or in vitro with mixed populations of tumor cells, we have seen that the simple prediction that treatment response would reflect the sensitivities of the individual subpopulations was not valid.

Inhibition of glycoprotein oligosaccharide processing in vitro and in influenza-virus-infected cells by alpha-D-mannopyranosylmethyl-p-nitrophenyltriazene.

The effects of alpha-D-mannopyranosylmethyl-p-nitrophenyltriazene (MMNT) on mannosidases involved in asparagine-linked oligosaccharide processing were investigated. MMNT was found to inhibit the activity of rat liver Golgi alpha-mannosidase I in a concentration-dependent manner (50% inhibition with 0.18 mM-MMNT), whereas rat liver endoplasmic-reticulum alpha-mannosidase appeared to be resistant (less than 5% inhibition at 1 mM-MMNT).

Dominance of a tumor subpopulation line in mixed heterogeneous mouse mammary tumors.

When mixtures of cell lines 168 and 4T07, both derived from the same mouse mammary tumor, were injected into syngeneic mice, the resulting tumors, analyzed over a large size range by colony-forming assays in selective media, consisted primarily of line 4T07, even when the ratio injected was 100:1 or greater in favor of line 168. This result indicated a suppression of growth of line 168, since the volume-doubling time of line 168 tumors in the absence of line 4T07 was one-half that of line 4T07 tumors. That growth suppression was not due to inhibition of line 168 by immunity induced to line 4T07 was shown in two ways: (a) line 168 tumors grew almost as well in mice preimmunized with line 4T07 as in controls, whereas line 4T07 tumor growth was strongly inhibited in preimmunized mice; and (b) the final composition (favoring line 4T07) in mixed tumors was similar in tumors grown in mice immunosuppressed by irradiation to that in nonirradiated controls.

Pre- and postcolumn derivatization chemistry in conjunction with HPLC for pharmaceutical analysis.

Descriptions of derivatization reactions applied to high-performance liquid chromatography for pharmaceuticals classified as alkaloids, amines, antibiotics, barbiturates, carbonyl/carboxylic compounds, catecholamines, hydroxy compounds, steroids, sulfur compounds, and miscellaneous are summarized.

Stimulation of surfactant phospholipid biosynthesis in the lungs of rats treated with silica.

The effects of intratracheally instilled silica (10 mg/rat) on the biosynthesis of surfactant phospholipids was investigated in the lungs of rats. The sizes of the intracellular and extracellular pools of surfactant phospholipids were measured 7, 14 and 28 days after silica exposure. The ability of lung slices to incorporate [14C]choline and [3H]palmitate into surfactant phosphatidylcholine (PC) and disaturated phosphatidylcholine (DSPC) was also investigated.

Isolation and characterization of hypertrophic type II cells from the lungs of silica-treated rats.

Type II cells isolated from the lungs of rats exposed to silica can be separated into two populations by using centrifugal elutriation. One population, designated type IIA, appears similar to type II cells isolated from control lungs. The second population, designated type IIB, consists of type II cells that are larger than type IIA cells or control type II cells.

Spontaneous fusion between metastatic mammary tumor subpopulations.

This study describes a differential frequency of spontaneous fusion between metastatic and nonmetastatic subpopulations derived from a single mouse mammary tumor. Subpopulations 66, 66c14 (a variant of 66 which is resistant to both thioguanine and ouabain), 410.4, and 44FTO (a thioguanine-resistant, ouabain-resistant derivative of 410.

Partial characterization of a novel endogenous opioid in human cerebrospinal fluid.

Human cerebrospinal fluid (CSF) contains many uncharacterized endogenous opioids, in addition to the known enkephalins, endorphins, and dynorphins. These opioids may be separated by gel filtration chromatography and identified by radioreceptor assay for opioid activity. One region of the chromatographic elution profile, designated "Peak B" has previously been shown to be related to the pain status of chronic pain patients.

Analysis of tumour cell composition in tumours composed of paired mixtures of mammary tumour cell lines.

In order to quantitate the effects of tumour subpopulation interactions, we have devised a method to determine the subpopulation composition of tumours by using paired tumour cell lines able to grow in different selective media. Line 4T07 forms colonies in thioguanine but not in HAT and line 168 forms colonies in HAT but not in thioguanine. An independent technique of determining tumour cell content was used to validate this method: line 168 and 4T07 cells are distinguishable by flow cytometry after staining with propidium iodide for DNA content.

Progression of type II cell hypertrophy and hyperplasia during silica-induced pulmonary inflammation.

Type II cell hyperplasia and hypertrophy were quantitated in the lungs of rats exposed to silica by using intratracheal injection. Hypertrophic type II cells were separated from normal type II cells by means of centrifugal elutriation of cells dispersed from the lungs by using protease. Type II cell hypertrophy was also quantitated, in situ, by measuring cell profile areas in lung sections.

The crystal structure of diazomethyl beta-D-galactopyranosyl ketone.

The title compound (C8H12N2O6) crystallizes in the orthorhombic space group P2(1)2(1)2(1) (Z = 4), with a = 4.871(1), b = 11.136(2), c = 18.

Tumor micro-ecology and competitive interactions.

Three nested models describing the growth of individual subpopulations in a heterogeneous environment are described. The models represent the dynamics of two populations which compete, to varying degrees, for common resources. The first model describes growth in a totally non-competitive micro-environment, the second model describes an ecology in which competition is proportional to competitor population size, and the third model ecology extends the model described by Jansson & Revesz (1974), which allows one population to emerge from the other.

An antibody that blocks insulin-like growth factor (IGF) binding to the type II IGF receptor is neither an agonist nor an inhibitor of IGF-stimulated biologic responses in L6 myoblasts.

To better define the biologic function of the type II insulin-like growth factor (IGF) receptor, we raised a blocking antiserum in a rabbit by immunizing with highly purified rat type II IGF receptor. On immunoblots of crude type II receptor preparations, only bands corresponding to the type II IGF receptor were seen with IgG 3637, indicating that the antiserum was specific for the type II receptor. Competitive binding and chemical cross-linking experiments showed that IgG 3637 blocked binding of 125I-IGF-II to the rat type II IGF receptor, but did not block binding of 125I-IGF-I to the type I IGF receptor, nor did IgG 3637 block binding of 125I-insulin to the insulin receptor.

Binding properties of human thrombospondin: interaction with mucopolysaccharides.

The interaction of human thrombospondin with mucopolysaccharides has been measured quantitatively. Binding of thrombospondin to heparin was examined utilizing an assay employing an 125I-labeled LMW heparin glycosaminoglycan (Mr = 8500). By this means, a class of binding sites was detected that bound approximately 2 moles of LMW heparin per mole of thrombospondin with a Kd of 2.

Purification of the cysB protein from Salmonella typhimurium.

Using an assay based on polypeptide mobility in one- and two-dimensional polyacrylamide electropherograms, we purified the Salmonella typhimurium cysB protein from an Escherichia coli strain carrying plasmid pGBK14, in which the S. typhimurium cysB gene is under transcriptional control of the strong promoter PL from phage lambda. cysB protein constitutes approximately 4% of total soluble protein in such cells and was obtained with good yield at a purity of 85% after precipitation of nucleic acids with streptomycin sulfate, ammonium sulfate fractionation, and hydrophobic chromatography on methyl agarose.

Alkaline phosphatase histochemistry discriminates peritubular cells in primary rat testicular cell culture.

Histochemical demonstration of alkaline phosphatase activity appears to be useful in identifying rat peritubular cells in primary testicular cell culture. In both frozen sections of rat testis and Mirsky's fixed, methacrylate-embedded rat testis, the reaction product localized primarily in peritubular cells, vascular endothelium and occasionally in interstitial cells, with much smaller amounts of reaction product associated with elongating spermatids in the germinal epithelium. Occasional late-stage tubules (X-XIV) showed weak reactivity in the epithelium, associated with spermatocytes or Sertoli cells.

Characterization of thrombospondin as a substrate for factor XIII transglutaminase.

Thrombin activation of platelets induces the release of a high molecular weight glycoprotein, thrombospondin. On treatment with factor XIII transglutaminase and [3H]putrescine, thrombospondin undergoes specific incorporation of this labeled amine, with 2-3 mol of putrescine being incorporated per mol of thrombospondin. Analysis of plasmin digests of [3H]putrescine-thrombospondin showed that the Mr 53,000-core peptide contains the glutamine site for amine incorporation.

Clinical pharmacology of aminoglutethimide in patients with metastatic breast cancer.

The pharmacology of aminoglutethimide (AG) was studied in two subsequent trials without hydrocortisone supplementation. A total of 79 patients with metastatic breast cancer entered the study, and their plasma and urine samples were analyzed by high-performance liquid chromatography (HPLC). Thirty evaluable patients with a median age of 57 years (range, 37-79) were treated with the standard dose of 1000 mg/day, and 37 evaluable patients with a median age of 59 years (range, 35-79) received 500 mg/day.

Quantitation of silica-induced type II cell hyperplasia by using alkaline phosphatase histochemistry in glycol methacrylate embedded lung.

A light microscopic technique based on alkaline phosphatase histochemistry was developed to specifically quantitate Type II cells in the intact rat lung. Lungs were fixed in 4% neutral-buffered formalin containing 0.25 M sucrose and embedded in glycol methacrylate.