Publisher Summary The classification of cell death can be based on morphological or biochemical criteria or on the circumstances of its occurrence. Currently, irreversible structural alteration provides the only unequivocal evidence of death; biochemical indicators of cell death that are universally applicable have to be precisely defined and studies of cell function or of reproductive capacity do not necessarily differentiate between death and dormant states from which recovery may be possible. It has also proved feasible to categorize most if not all dying cells into one or the other of two discrete and distinctive patterns of morphological change, which have, generally, been found to occur under disparate but individually characteristic circumstances. One of these patterns is the swelling proceeding to rupture of plasma and organelle membranes and dissolution of organized structure—termed “coagulative necrosis.” It results from injury by agents, such as toxins and ischemia, affects cells in groups rather than singly, and evokes exudative inflammation when it develops in vivo. The other morphological pattern is characterized by condensation of the cell with maintenance of organelle integrity and the formation of surface protuberances that separate as membrane-bounded globules; in tissues, these are phagocytosed and digested by resident cells, there being no associated inflammation.

Cell death : the significance of apoptosis

Publisher Summary This chapter explores that the changes that take place in the protein molecules during denaturation constitute one of the most interesting and complex classes of reactions that can be found either in nature or in the laboratory These reactions are important because of the information they can provide about the more intimate details of protein structure and function They are also significant because they challenge the chemist with a difficult area for the application of chemical principles The chapter reviews that the denaturation is a process in which the spatial arrangement of the polypeptide chains within the molecule is changed from that typical of the native protein to a more disordered arrangement The chapter also discusses the classification of protein structures: primary, secondary, and tertiary structures The primary structure is that expressed by the structural chemical formula and depends entirely on the chemical valence bonds that the classical organic chemist would write down for the protein molecule The secondary structure is the configuration of the polypeptide chain that results from the satisfaction of the hydrogen bonding potential between the peptide N-H and C=O groups The tertiary structure is the pattern according to which the secondary structures are packed together within the native protein molecule The term “denaturation” as used in this chapter is indented to include changes in both the secondary and tertiary structures

Some factors in the interpretation of protein denaturation.

The rat estrogen receptor (ER) exists as two subtypes, ER alpha and ER beta, which differ in the C-terminal ligand binding domain and in the N-terminal transactivation domain. In this study we investigated the messenger RNA expression of both ER subtypes in rat tissues by RT-PCR and compared the ligand binding specificity of the ER subtypes. Saturation ligand binding analysis of in vitro synthesized human ER alpha and rat ER beta protein revealed a single binding component for 16 alpha-iodo-17 beta-estradiol with high affinity [dissociation constant (Kd) = 0.1 nM for ER alpha protein and 0.4 nM for ER beta protein]. Most estrogenic substances or estrogenic antagonists compete with 16 alpha-[125I]iodo-17 beta-estradiol for binding to both ER subtypes in a very similar preference and degree; that is, diethylstilbestrol > hexestrol > dienestrol > 4-OH-tamoxifen > 17 beta-estradiol > coumestrol, ICI-164384 > estrone, 17 alpha-estradiol > nafoxidine, moxestrol > clomifene > estriol, 4-OH-estradiol > tamoxifen, 2-OH-estradiol, 5-androstene-3 beta, 17 beta-diol, genistein for the ER alpha protein and dienestrol > 4-OH-tamoxifen > diethylstilbestrol > hexestrol > coumestrol, ICI-164384 > 17 beta-estradiol > estrone, genistein > estriol > nafoxidine, 5-androstene-3 beta, 17 beta-diol > 17 alpha-estradiol, clomifene, 2-OH-estradiol > 4-OH-estradiol, tamoxifen, moxestrol for the ER beta protein. The rat tissue distribution and/or the relative level of ER alpha and ER beta expression seems to be quite different, i.e. moderate to high expression in uterus, testis, pituitary, ovary, kidney, epididymis, and adrenal for ER alpha and prostate, ovary, lung, bladder, brain, uterus, and testis for ER beta. The described differences between the ER subtypes in relative ligand binding affinity and tissue distribution could contribute to the selective action of ER agonists and antagonists in different tissues.

Comparison of the ligand binding specificity and transcript tissue distribution of estrogen receptors alpha and beta

Protein extracts derived from bone can initiate the process that begins with cartilage formation and ends in de novo bone formation. The critical components of this extract, termed bone morphogenetic protein (BMP), that direct cartilage and bone formation as well as the constitutive elements supplied by the animal during this process have long remained unclear. Amino acid sequence has been derived from a highly purified preparation of BMP from bovine bone. Now, human complementary DNA clones corresponding to three polypeptides present in this BMP preparation have been isolated, and expression of the recombinant human proteins have been obtained. Each of the three (BMP-1, BMP-2A, and BMP-3) appears to be independently capable of inducing the formation of cartilage in vivo. Two of the encoded proteins (BMP-2A and BMP-3) are new members of the TGF-beta supergene family, while the third, BMP-1, appears to be a novel regulatory molecule.

https://science.sciencemag.org/content/sci/242/4885/1528.full.pdf

Novel regulators of bone formation: molecular clones and activities.

Thereisgrowinginterestinthepossiblehealththreatposedbyendocrine-disruptingchemicals (EDCs), which are substances in our environment, food, and consumer products that interfere with hormone biosynthesis, metabolism, or action resulting in a deviation from normal homeostatic control or reproduction. In this first Scientific Statement of The Endocrine Society, we present the evidence that endocrine disruptors have effects on male and female reproduction, breast development and cancer, prostate cancer, neuroendocrinology, thyroid, metabolism and obesity, and cardiovascular endocrinology. Results from animal models, human clinical observations, and epidemiological studies converge to implicate EDCs as a significant concern to public health. The mechanisms of EDCs involve divergent pathways including (but not limited to) estrogenic, antiandrogenic, thyroid, peroxisome proliferator-activated receptor , retinoid, and actions through other nuclear receptors; steroidogenic enzymes; neurotransmitter receptors and systems; and many other pathways that are highly conserved in wildlife and humans, and which can be modeled in laboratory in vitro and in vivo models. Furthermore, EDCs represent a broad class of molecules such as organochlorinated pesticides and industrial chemicals, plastics and plasticizers, fuels, and many other chemicals that are present in the environment or are in widespread use. We make a number of recommendations to increase understanding of effects of EDCs, including enhancing increased basic and clinical research, invoking the precautionary principle, and advocating involvement of individual and scientific society stakeholders in communicating and implementing changes in public policy and awareness. (Endocrine Reviews 30: 293–342, 2009)

/pdf/endocrine-disrupting-chemicals-an-endocrine-society-3fgbtp8gql.pdf

Endocrine-Disrupting Chemicals: An Endocrine Society Scientific Statement

In the experiments to be described, it was observed that the administration of 7,12-dimethylbenz(a)anthracene (7,12-DMBA) prior to the injection of tritiumlabeled thymidine (TdRH3) considerably depresses the incorporation of tritium into rat testis, intestine, and adrenal. Recovery from the effect of 7,12-DMBA occurs in intestine within 48 hr but in testis the inhibitory action of a single dose of 7,12-DMBA persists longer. Fractionation of the testis demonstrated that the decrease in tritium content is associated entirely with the perchloric acid-insoluble fraction. 7,12-DMBA is of special interest for several reasons. (1) A single dose evokes mammary cancer selectively, invariably, and rapidly in the rat under conditions which are easily satisfied.' (2) A single dose of the hydrocarbon invariably induces massive and selective necrosis of two of the zones of adrenal cortex2 of adult, but not of infant, rats.3 (3) In male rats, a solitary injection of 7,12-DMBA inflicts selective damage in the testicular cells which actively synthesize deoxyribonucleic acid (DNA) and only in cells of this class.4 Death of male germinal cells is not sudden, but occurs only after the injured cells have undergone one or several mitotic divisions. These spectacular biological effects of 7,12-DMBA made it desirable to investigate the influence of this compound upon the incorporation of thymidine into the DNA of testis and other tissues. Experimental.-Male rats of Sprague-Dawley strain were used exclusively; there were 4 animals in each group. Each experiment was repeated on 3 separate occasions with similar results. Tritium-labeled thymidine,5 specific activity of 3 c/mmol, was diluted with aqueous sodium chloride (0.9%), and a 1 ml dose, corresponding to approximately 1 gc/gm of body weight, was injected into a caudal vein. 7,12-DMBA, mp 122-3°, purified by Florisil chromatography and recrystallized from acetone-ethanol, was made up in lipide emulsion5 and injected once only into a caudal vein at various time intervals before or after the TdRH3. Infant rats, age 25 days weighing 52-70 gi, received 2 mg of 7,12-DMBA in 0.4 ml of emulsion; -adult rats, age 50 days weighing 200-220 gm, received 5 mg of 7,12DMBA in 1 ml of emulsion. The animals were killed by decapitation, and testis, adrenal, and a segment of terminal ileum were excised and weighed. For determination of the total volatile and nonvolatile radioactivity, each tissue was dried from the frozen state; the evaporated water was collected in a cold trap and counted directly, whereas the dry residue (triplicate samples for testis) was analyzed for tritium by the combustion procedure described previously.6 For determination of tritium in the acid-soluble and acid-insoluble fractions, the weighed testis was homogenized for 3 min in 4 ml of ice-cold 0.5 N perchloric acid containing 0.5 mg of nonradioactive thymidine per ml. All procedures after weighing were were carried out at a temperature of 40 or

Depressed incorporation of thymidine-h3 into deoxyribonucleic acid following administration of 7,12-dimethylbenz(alpha)anthracene.

Adrenalectomy for mammary cancer; surgical technic of bilateral one-stage adrenalectomy in man.

Nine of 15 patients, including one man, with advanced mammary cancer were improved by treatment with a combination of 50 mg. of progesterone and 5 mg. of estradiol benzoate administered intramuscularly every day. Seven of the 9 had previously responded to endocrine therapy (adrenalectomy, hypophysectomy, castration, estrogen or androgen). Serum alkaline phosphatase concentrations rose during the first 2 weeks of treatment in all the patients in whom the disease was ameliorated, but in only 2 of the 6 who were not improved. No toxic or adverse reactions were observed. Although the benefit secured by this treatment was sometimes short-lived, the results seemed sufficiently encouraging to merit more exhaustive trials.

Estradiol Benzoate and Progesterone in Advanced Human-Breast Cancer: A Combination Found Effective in Advanced Cases

Brief exposure of rat bone matrix to highly charged electrochemicals had profound but reversible effects on its competence to transform fibroblasts into chondroblasts and osteoblasts. Suppression and subsequent reactivation of this function were influenced critically by the charge of the electrochemical reagent and the pH of the reaction mixture. In dilute acids, Evans Blue, a long electronegative molecule, suppressed transforming competence, whereas hexadimethrine, a polycationic quaternary ammonium base, failed to do so. A cycle of inactivation-restoration of transforming competence was achieved by sequential treatment of bone matrix with Evans Blue followed by hexadimethrine; an electrochemical complex was demonstrated by histochemistry. In dilute alkalies, hexadimethrine inhibited, whereas, Evans Blue did not suppress the transforming function of the bone matrix. Electric charge characteristics on the surface of the bone matrix are of crucial significance for the fibroblast-transforming attribute.

Cyclic Electrochemical Inactivation and Restoration of Competence of Bone Matrix to Transform Fibroblasts

A series of pulse-doses of 7, 8, 12-trimethylbenz(a)anthracene-induced leukemia rapidly and consistently in very high yield in rats of Long-Evans (L-E) strain. The predominant type was a diffuse hepatic leukemia of erythroblastic stem cells. Progressive hypothermia and a decline in pituitary function are newly recognized signs of advanced leukemia in rat.

https://rupress.org/jem/article-pdf/131/2/321/1083589/321.pdf

Charles Huggins

Papers

Depressed incorporation of thymidine-h3 into deoxyribonucleic acid following administration of 7,12-dimethylbenz(alpha)anthracene.

Adrenalectomy for mammary cancer; surgical technic of bilateral one-stage adrenalectomy in man.

Estradiol Benzoate and Progesterone in Advanced Human-Breast Cancer: A Combination Found Effective in Advanced Cases

Cyclic Electrochemical Inactivation and Restoration of Competence of Bone Matrix to Transform Fibroblasts

Hundred day leukemia: preferential induction in rat by pulse-doses of 7,8,12-trimethylbenz(a)anthracene