Microfluorometric estimates of proteins associated with murine hepatocyte and thymocyte nuclei, residual structures, and nuclear matrix derivatives

Isolated diploid hepatocyte and thymocyte nuclei and their derivatives ("residual structures" and nuclear matrices, as defined by Kaufmann et al. 1981) were evaluated by microfluorometry following reaction with the following fluorochromes: brilliant sulfaflavine (BSF) used at pH 2.8 for the demonstration of total protein; acridine orange (AO) used at pH 9.0 to reveal acidic groups of proteins; and 3-(4-maleimidylphenyl)-7-diethylamino-4-methylcoumarin (CPM) used under conditions required to demonstrate the sum of sulfhydryl (SH) and disulfide (SS) groups of proteins. The results suggested that the proteins reacting with AO and CPM differed from each other and from those revealed by fluorochroming with BSF. In every comparison, hepatocyte nuclei and their derivatives were more fluorescent than the respective populations of thymocyte nuclei and their derivatives. In material fluorochromed with BSF and AO, nuclear matrices were less fluorescent than residual structures, which, in turn, were less fluorescent than intact nuclei. In contrast, nuclear matrices fluorochromed with CPM were less fluorescent than intact nuclei but more fluorescent (paradoxically) than residual structures. The ratios of the total fluorescence values of hepatocyte and thymocyte nuclei fluorochromed with BSF changed significantly during extractions required to produce residual structures and nuclear matrices, while comparable ratios in material fluorochromed with AO or CPM did not change significantly. Comparisons of the ratios of the fluorescence values of intact nuclei and their derivatives in a variety of combinations yielded complex and variable results.(ABSTRACT TRUNCATED AT 250 WORDS)     

On the diphasic nature of vasovagal fainting associated with blood-injury-illness phobia

A detailed psychophysiologic analysis of a vasovagal faint occurring in a "blood-injury-illness" phobic demonstrated that the syncopal episode consisted of a diphasic response. This lends support to the hypothesis that vasovagal fainting in these patients is caused by an overcompensating rebound parasympathetic activation following sympathetic arousal. Treatment and research implications of this finding are discussed.     

Analysis of Cell Types Identifiable In Air-Dried Cell Preparations of Human Testis

Abstract. The mixed cell population of the testicular epithelium has been studied in air-dried cell preparations obtained from a testicular biopsy. Observed cell types are defined, quantified and assigned to cell stages of the spermatogenic cycle. Studies with tritiated thymidine helped to categorize the spermatogonial cell types. Variation in cell size within cell categories, variation in frequency of cells in different categories within individuals, and variation in frequency of cells within categories between individuals were subjected to quantitative analysis.     

Multiple primary cancers in Connecticut, 1935-82

Recently, the National Cancer Institute published a comprehensive monograph on multiple primary cancers in Connecticut and Denmark. This paper summarizes some of the observations made on the Connecticut population. Data compiled by the Connecticut Tumor Registry have extended our knowledge about the patterns of multiple primary cancers, especially among long-term survivors of cancer and among patients with relatively rare tumors about which little information currently exists. When compared with the general Connecticut population, cancer patients had a 31 percent (RR = 1.31) increased risk of developing a second cancer and a 23 percent (RR = 1.23) elevated risk of second cancer at a different site from the first. Common environmental exposures seemed responsible for the excess occurrence of many second cancers, particularly those related to cigarette smoking, alcohol consumption, or both. For example, persons with epithelial cancers of the lung, larynx, esophagus, buccal cavity, and pharynx were particularly prone to develop new cancers in the same or contiguous tissue throughout their lifetimes. Cancers of the colon, uterine corpus, breast, and ovary frequently occurred together, suggesting underlying hormonal or dietary influences. Only patients with prostate cancer were at significantly low risk for second cancer development; this might be an artifact of case finding, since advanced age at initial diagnosis was generally associated with an underascertainment of second cancers. Radiotherapy may have caused rectal and other cancer among patients with cancers of the female genital tract, and leukemia among patients with uterine corpus cancer. Chemotherapy with alkylating agents probably contributed to the excess of acute nonlymphocytic leukemia following multiple myeloma or cancers of the breast and ovary. Genetic susceptibility seemed to explain some tumor complexes, such as the multiple occurrences of cutaneous melanoma and the excess of bone cancer following retinoblastoma. Research into multiple cancer syndromes should enhance our understanding of carcinogenic factors and mechanisms and the development of strategies for cancer prevention and control.     

Solubilization of the calcium antagonist receptor from rat brain

[3H]Nitrendipine binds with high affinity to a calcium antagonist receptor in rat brain membranes. At 4 degrees C, treatment with digitonin solubilized the calcium antagonist receptor as a stable complex with [3H]nitrendipine. The nitrendipine concentration that gave a half-maximal amount of the solubilized [3H]nitrendipine-receptor complex was identical to the Kd for specific nitrendipine binding to brain membranes. Nitrendipine dissociated from digitonin-solubilized and membrane-bound receptors with a half-time of 24 to 30 min at 20 degrees C. Verapamil increased and diltiazem decreased the dissociation rate to a similar extent in both preparations indicating that the solubilized receptor contains both the dihydropyridine and diltiazem/verapamil binding sites. Sucrose gradient sedimentation experiments gave a value of S20, omega = 19.2 for the receptor-digitonin complex. The solubilized calcium antagonist receptor binds specifically to wheat germ agglutinin-Sepharose columns consistent with an identification as a glycoprotein.     

Action of two juvenile hormone antagonists on lepidopteran epidermis

The juvenile hormone antagonist ETB (ethyl-4-2(t-butylcarbonyloxy)-butoxybenzoate) caused formation of precocious larval-pupal intermediates after the 4th (penultimate)-larval instar of the tobacco hornworm, Manduca sexta, when 50 μg were applied to any 3rd stage larvae or to 4th stage larvae within 12 hr after ecdysis. This dose was most effective within 12 hr after ecdysis to the 3rd stage. In the black mutant larval assay for juvenile hormone, ETB had activity, 0.75 μg per larva giving half-maximal score. In vitro ETB acted as a juvenile hormone to prevent the ecdysteroid-induced change in commitment at concentrations above 0.1 μg/ml with an ED₅₀ at 2.8 μg/ml and as a partial juvenile hormone antagonist to 0.1 μg/ml juvenile hormone I at concentrations between 10^?3 and 10^?2 μg/ml. By contrast, EMD (ethyl-E-3-methyl-2-dodecenoate) had little juvenile hormone-like activity in vitro up to its limits of solubility (100 μg/ml) and exhibited sporadic partial juvenile hormone antagonistic activity in vitro at concentrations between 1 and 100 μg/ml. Since these concentrations were 10–1000 times that of juvenile hormone I in the medium, EMD apparently is not an efficient competitor.     

The metabolism of macromolecules during the differentiation of myxamoebae of the cellular slime mould Dictyostelium discoideum containing different amounts of glycogen

1. Methods of obtaining myxamoebae of Dictyostelium discoideum strain Ax-2 (ATCC 24397) with glycogen contents in the range 0.05-5mg of glycogen/10(8) cells are described. The changes in cellular glycogen, protein and RNA content during the differentiation of such myxamoebae were determined. 2. Myxamoebal glycogen is not conserved during differentiation and gluconeogenesis may occur even in cells that contain a large amount of glycogen initially. 3. There is a marked net loss of cellular protein and RNA during differentiation and associated with this there are also marked decreases in the sizes of the intracellular pools of amino acids, acid-soluble proteins and pentose-containing materials. 4. During the early stages of development some protein and pentose(s) are excreted, but this cannot account for the decreased cellular content of protein and RNA. 5. There is a linear rate of production of NH(3) during development, and oxidation appears to be the fate of the major portion of the degraded protein and RNA. 6. However, provision of an alternative metabolizable energy source (glycogen) has little effect on the rate or extent of protein or RNA breakdown or on the changes in the sizes of the intracellular pools of amino acids, acid-soluble proteins and pentose-containing materials. 7. It is concluded that during development there is a requirement for the destruction of specific RNA and protein molecules for reasons other than the provision of oxidizable substrates. 8. The kinetic model of Wright et al. (1968) is discussed in relation to these changes in macromolecular content.