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Biomedical subjects

L L Anderson

Publications and source records attributed to L L Anderson.

At least 181 records · Page 10Linked to original sources
PubMed1979

Progesterone secretion and fetal development during prolonged starvation in the pig.

Roles of ovarian progesterone secretion and maternal nutrition in fetal development were investigated in a species that normally experiences considerable embryonic and fetal mortality. Pregnancies were maintained in 81% of Yorkshire pigs during prolonged starvation (e.g., 40 days; 0 kcal/day, water only) in either the middle third (days 30-70) or last third (days 70-110) of gestation compared with 100% in full-fed controls (7,028 kcal/day). In spite of severe maternal deprivation, fetal survival rates averaged 65% in starved dams and 63% in controls; mean number of living fetuses was 9.9 in starved and 9.6 in control dams. Fetal growth was reduced by maternal starvation during the middle third, but not the last third of pregnancy. Placental insufficiency was the primary cause of reduced fetal growth and resulted in abortion in a few of the dams. Progesterone in peripheral serum of dams starved either during middle or late pregnancy was maintained at levels similar (P greater than 0.05) to those in controls. Abortion occurred in starved dams only when serum progesterone concentrations dropped to less than 10 ng/ml within 3 days before loss of conceptuses.

Animals↗
PubMed1979

Maternal starvation and progesterone secretion, litter size, and growth in the pig.

The relationships of maternal nutrition and progesterone secretion to prenatal fetal loss and neonatal survival and growth were investigated in domesticated pigs that normally experience 40% fetal loss. Yorkshire pigs were subjected to prolonged starvation (40 days; 0 kcal/day; water only) in either the middle third or last third of pregnancy and then gradually realimented to a full diet and allowed to advance to parturition; controls received a full diet (7,028 kcal/day) throughout gestation. Pregnancies were maintained in 74% of the pigs starved during either middle or late gestation compared to 100% in controls. In dams starved from days 30--70, progesterone levels remained similar to controls, but were maintained at lower levels during realimentation between days 72 and 99. Progesterone levels in dams starved days 50--90 and controls were similar from days 50 to 130. At parturition, litter size in starved dams (9.4) was similar to full-diet controls (8.0) although birth weight and neonatal growth of piglets were reduced markedly from dams starved in middle or late pregnancy. These results indicate that severe maternal nutrient deprivation during the middle or last third of gestation has little effect on ovarian progesterone secretion and is not a major limitation to fetal survival in this litter-bearing species. Maternal nutrient deprivation imposes a significant detrimental effect, however, on birth weight and neonatal growth to 80 days of age.

Animals↗
PubMed1978

Cyanate modification of essential lysyl residues in the catalytic subunit of tobacco ribulosebisphosphate carboxylase.

Crystalline ribulose-1,5-bisphosphate carboxylase (3-phospho-D-glycerate carboxy-lyase (dimerizing), EC 4.1.1.39) isolated from tobacco (Nicotiana tabacum L.) leaf homogenates is irreversibly inactivated by incubation with potassium cyanate at pH 7.4. The rate of inactivation is pseudo first-order and linearly dependent on reagent concentration. In the presence of ribulosebisphosphate or high levels of CO2 and Mg2+ the rate constant for inactivation is reduced, suggesting that chemical modification occurs in the active site region of the enzyme. In contrast, neither the effector NADPH nor the activator Mg2+ alone significantly affect the rate of inactivation by cyanate; however, NADPH markedly enhances the protective effect of CO2 and Mg2+. Incubation of the carboxylase with potassium [14C] cyanate in the absence or presence of ribulosebisphosphate revealed that the substrate specifically reduces cyanate incorporation into the large catalytic subunits of the enzyme. Analysis of acid hydrolysates of the radioactive carboxylase indicated that the reagent carbamylates both NH2-terminal groups and lysyl residues in the large and small subunits. Comparison of the substrate-protected enzyme with the inactivated carboxylase revealed that ribulosebisphosphate preferentially reduces lysyl modification within the large subunit. The data here presented indicate that inactivation of ribulosebisphosphate carboxylase by cyanate or its reactive tautomer, isocyanic acid, results from the modification of lysyl residues within the catalytic subunit, presumably at the activator and substrate CO2 binding sites on the enzyme.

Carboxy-Lyases↗
PubMed1978

Growth, protein content and distribution of early pig embryos.

Development of porcine conceptuses included transitions of five stages: blastocysts of spherical, ovoid, and tubular forms containing an embryonic disc and trophoblast, extremely elongated filamentous blastocysts, and stages of embryogenesis between days 9 and 18 after mating. Embryonic survival was reduced by 17% during this period. In this litter-bearing species, intense alteration in distribution patterns occurred at days 11 and 12, when blastocysts rapidly elongated to filamentous forms. Increased embryo mortality did not result from rapid changes in distribution patterns of conceptuses within the same uterine horn at this time. Filamentous blastocysts quickly reached lengths often exceeding 60 cm, and these conceptuses became regularly spaced with no overlap of tubular membranes from other embryos in that horn. The number of conceptuses within a uterine horn ranged from 1 to 13. Protein in individual conceptuses was used as an indicator of growth and denoted exponential increase, but at a lower rate for blastocysts of spherical, ovoid, and tubular forms as compared with that found in filamentous blastocysts and embryogenesis stage conceptuses. Growth on a conceptus, based upon its protein content, was independent of the developmental stage or potential loss of those neighbors nearest that conceptus.

Animals↗
PubMed1977

Conformational changes associated with the reversible cold inactivation of ribulose-1,5-bisphosphate carboxylase-oxygenase.

Crystalline ribulose-1,5-bisphosphate carboxylase-oxygenase (3-phospho-D-glycerate carboxy-lyase (dimerising), EC 4.1.1.39) isolated from tobacco (Nicotiana tabacum L.) leaf homogenates is partially inactivated by cold treatment and fully reactivated by simple heating in the absence of sulfhydryl reagents and effectors. Since the reversible cold inactivation of this bifunctional enzyme does not involve a gross change in the association state of subunits, a subtle conformational change induced by low temperatures was implicated (Chollet, R. and Anderson, L.L. (1976) Arch. Biochem. Biophys. 176, 344-351). Chemical modification of the cold-inactivated and heat-reactivated enzymes by 5,5'-dithiobis-(2-nitrobenzoate) and p-mercuribenzoate at 25 degrees C revealed no difference in the number of free -SH groups per mol protein. However, the reactivity of the sulfhydryl residues on the inactivated protein was considerably greater than that of the reactivated enzyme. Pretreatment of the two proteins with sodium dodecyl sulfate completely abolished the difference in -SH reactivity, indicating its dependence on protein conformation. Both the cold-inactivated and heat-reactivated enzymes enhanced the fluorescence intensity of 8-anilino-1-naphthalenesulfonate (ANS) and caused a blue shift of the emission maximum from 510 to 472 nm. When the inactivated enzyme was reactivated by heating, the increase in catalytic activity was closely paralleled by a concomitant decrease in the fluorescence intensity of the ANS - protein complex at 25 degrees C. Fluorescence titration experiments revealed that the decrease in fluorescence intensity accompanying heat reactivation of the inactivated enzyme was due to a reduction in the number of hydrophobic sites available for ANS binding rather than to a change in the dissociation constant of the ANS - protein complex. These results indicate that the reversible cold inactivation of ribulose-1,5-bisphosphate carboxylase-oxygenase is associated with a reversible change in the conformation of the protein. This cold-induced conformational change resluts in a greater exposure of sulfhydryl groups and hydrophobic regions to the external environment and is closely paralleled by changes in the catalytic activity of the protein. By analogy to other oligomeric enzymes also subject to reversible cold inactivation, perhaps low temperatures induce a partial dissociation of the octameric structure of the hydrophobic catalytic subunits, but complete dissociation is arrested in some unknown manner by the small hydrophilic subunits.

Anilino Naphthalenesulfonates↗
PubMed1977

Development in calves and heifers after hypophysial stalk transection or hypophysectomy.

Growth was inhibited markedly in prepuberal bull and heifer calves after either hypophysial stalk transection or hypophysectomy as compared with that found in sham-operated calves or in unoperated calves. Male mounting behavior and evidence of puberal estrous behavior were lost or undetected after hypophysial stalk transection or hypophysectomy. Testes regressed, contained few spermatogonia and interstitial cells, and lacked spermatogenesis. Epithelial cells of seminal vesicles, bulbourethral glands, and prostate were cuboidal, indicating inadequate testicular androgen. Atresia of numerous ovarian follicles and reduced ovarian weight occurred in hypophysectomized heifer calves. Graafian follicles regressed after hypophysial stalk transection of sexually mature heifers, but ovaries responded to pregnant mare serum and human chorionic gonadotropin by follicular development, ovulation, and formation of multiple corpora lutea. Thyroid and adrenal gland weights decreased and adrenal cortices atrophied after hypophysectomy, but not after stalk transection. Thyroid glands contained colloid-filled follicles with flattened epithelial cells; atrophy was more extensive after hypophysectomy. Hypophysial stalk transection or hypophysectomy severely depresses growth and arrests sexual development in young calves, but in mature animals exongenous gonadotropins can sustain gonadal function.

Adrenal Glands↗
PubMed1976

Distribution and development of embryos in the pig.

The distribution and development of pig embryos were determined in relation to the number of embryos and their positions within the uterine horn between Days 14 and 34 after mating. The observed distribution of 1-11 embryos within a uterine horn was highly correlated (r = 0-96) with the theoretical expected distribution. Embryo spacing was uniform regardless of the number of embryos within the horn. Nitrogen content of the embryo in relation to its position within the uterine horn indicated that development was similar for embryos located at the utero-tubal end or cervical end and comparable to those located in the middle portion of the horm. Placental development, as indicated by nitrogen content, was similar regardless of location within the horn.

Animals↗
PubMed1976

Sialoproteinaemia: lack of correlation with inhibition of in vitro lymphoblastosis induced by phytohaemagglutinin or alloantigen.

Elevation of serum-bound sialic acid concentration in different disease states fails to correlate significantly with suppressive serum actions in mixed allogeneic lymphocyte cultures or phyto-haemagglutinin cultures. Heat-decomplemented serum from patients with abnormal levels of bound sialic acid was added to parallel cultures containing similar blood lymphocyte populations derived from normal humans. Wide fluctuations of the rate of incorporation of tritiated thymidine into nucleoprotein indicated presence of suppressive elements other than sialoprotein in the added serum components. Serum with rising sialyl concentration derived from patients with cancer showed slight tendency to augment mixed lymphocyte and phytohaemagglutinin responses. The findings suggest that the previously documented nonspecific suppressive action of serum sialoprotein on human host lymphoblastic response to neuraminidase-treated cancer cells represents a mechanism unique to that culture system rather than a manifestation of a general immunoregulatory function of serum sialoprotein.

Blood Protein Disorders↗
PubMed1975

Embryonic and placental development during prolonged inanition in the pig.

Pregnancy is maintained in a high percentage (79%) of pigs subjected to inanition for periods up to 37 days, but few (25%) remain pregnant when inanition continues beyond 41 days. All remain pregnant during prolonged inanition (45 days) when exogenous progesterone and estradiol benzoate are given daily. Embryo survival rates in animals on inanition remain high (88%) and similar to those (89%) found in pigs given a full diet. Nitrogen content of embryos increases at a decreasing rate after 41 and 45 days inanition; placental nitrogen is markedly reduced at those times. By 45 days of inanition, nitrogen contents of embryos and placentas are less (P less than 0.01) than found in dams receiving a full diet. During prolonged inanition, exogenous progesterone (80 mg/100 kg) and estradiol benzoate (500 mug/100 kg) maintain embryonic and placental development at levels similar to those found in animals on a full diet. Maternal stores of protein and energy are made available for embryonic and placental developement in the presence of adequate levels of progesterone and estrogen, in spite of severe body weight loss during prolonged inanition of the dam.

Animals↗
PubMed1974

Neuraminidase-mediated augmentation of in vitro immune response of patients with solid tumors.

Host blood lymphocytes undergo accentuated blastic transformation when cultured with tumor cells pretreated with neuraminidase. The effect has been observed in 38 patients with such common solid tumors as bronchus carcinoma, skin melanoma, hypernephroma, or adenocarcinoma of the breast, lung, colon, or rectum. Individual response varied but often exceeded response to allogeneic cells. Three patients with glioblastoma of the brain did not respond. Lymphoblastic transformation was not observed in three of four cultures containing benign tumor or in any cultures containing normal tissue analogues of the malignant tumors. A factor in host blood serum inhibiting lymphoblastic transformation correlated to abnormal elevation of serum-bound sialic acid. This blocking factor differed in specificity from enhancing antibody or serum blocking complexes described by other investigators. Blocking effects were observed when the tumor-cell type of a serum donor differed from the cell type of the culture test tumor. Serum with abnormal elevation of bound sialate from a cancerfree human also non-specifically blocked host response to tumor. The blocking effect could be eliminated by partial enzymatic removal of bound sialic acid from serum glycoproteins.

Adenocarcinoma↗