Influence of passive smoking on admissions for respiratory illness in early childhood

An association was sought between passive smoking and inpatient admissions for respiratory illness in 1058 children born between 1 June and 31 December 1981 and living in the neighborhoods of Nan-Jing Western Road and Yan-An Western Road in Jing-An District, Shanghai. The admission rate for first episodes of respiratory illness was positively correlated with the total daily cigarette consumption of family members during the children's first 18 months of life. The relative risk of developing a first episode of respiratory illness was 1.80 for children living in families including people who smoked 10 or more cigarettes a day compared with those living in non-smoking families. Multiple logistic regression analysis showed that the effect of passive smoking on inpatient admission for respiratory illness was independent of the child's birth weight, type of feeding, father's education, size of the home, and chronic respiratory disease among adults in the family. The adjusted odds ratios compared with the non-smoking group were 1.17 in families smoking 1.9 cigarettes daily and 1.89 in families smoking 10 or more cigarettes daily. These data suggest that exposure to household cigarette smoke of children in early life increases the risk of severe respiratory illness.

Inhibitory effect in vitro of PR toxin, a mycotoxin from Penicillium roqueforti, on the mitochondrial HCO-3-ATPase of the rat brain, heart and kidney

The effects of PR toxin, a mycotoxin from Penicillium roqueforti, on the mitochondrial HCO3- -ATPase activity of the brain, heart and kidney from male Sprague-Dawley rats were determined by measuring colorimetrically the inorganic phosphate liberated by the ATPase in the presence or absence of bicarbonate ion. The IC50 (the concentration at which 50% of the enzyme activity is inhibited) of PR toxin on the mitochondrial HCO3- -ATPase from brain, heart and kidney were 12.7, 9.2 and 14.8 microM, respectively. The Michaelis-Menten constants (Km) of the enzyme from brain (1.1 mM), heart (1.5 mM) and kidney (2.3 mM) were not changed by PR toxin. Neither neutral nor anionic detergent increased the inhibitory potency of the toxin. It was concluded that of the three tissues tested, HCO3- -ATPase of the heart mitochondria was most sensitive to PR toxin, and that the toxin inhibited the HCO3- -ATPase in a non-competitive and irreversible manner.

Maternal diazepam exposure on brain ornithine decarboxylase and growth of offspring

The prenatal treatment of diazepam on the developmental pattern of brain ornithine decarboxylase and the general growth of offspring were studied. Diazepam (120 mg/kg/day) was administered orally to pregnant Sprague-Dawley rats from day 14 to day 20 of gestation. The activity of brain ornithine decarboxylase and body weight of the offspring were measured from the late fetal stage to the early postnatal stage. It was found that diazepam inhibited both the prenatal and 4-hour postnatal ornithine decarboxylase activities, though the general maturation pattern of the enzyme in the brain was not much altered. It may indicate that diazepam inhibits early brain development. The enzyme activity fell off as it reached maturation. Prenatal treated neonates of 6-hour or older age group had the normal activities of brain ornithine decarboxylase. The general growth of the treated offspring was substantially retarded. Their body weights were very much lower than the control offspring. The results of the present study is an additional evidence that diazepam and other benzodiazepines should be used with great care in pregnant women.

The effect of immunity on pulmonary metastasis of a methylcholanthrene-induced fibrosarcoma and three of its clones

A 3-Methylcholanthrene (MC)-induced fibrosarcoma and three of its clones were investigated for their metastatic potential in normal and tumor immune mice. The growth rates of the four tumors in vivo were similar. However, the mean survival times of the tumor-bearing mice were markedly different. Clone 10, the most immunogenic, showed very high metastatic potential and short survival, while clone 27, the least immunogenic, produced few metastases, resulting in much longer survival. Moderate numbers of metastases were produced by highly immunogenic 3-AM (parental tumor), and poorly immunogenic clone 34. Spleen cells from mice bearing highly immunogenic tumors lost their ability to neutralize tumors by day 28 after tumor inoculation, while those from mice bearing poorly immunogenic tumors remained cytotoxic, indicating that highly immunogenic tumors also induced immune suppression in the hosts. Immunization with specific tumors decreased the number of pulmonary metastases by 3 to 35-fold. Immunization with tumors that shared antigens provided protection against metastatic tumors as well as the local tumors. In contrast, immunization with antigenically different tumors gave no protection.

Fibrinogen precursors. Order of assembly of fibrinogen chains

Hep-G2 cells, incubated with L-[35S]methionine, incorporate radioactivity into fibrinogen and several fibrinogen-related compounds. Pulse-chase experiments indicate that several of these compounds are precursors of fibrinogen and that the cells contain intracellular pools of A alpha and gamma chains which participate in the assembly of fibrinogen. The rate of synthesis of the three component chains of fibrinogen is unequal with that of the B beta chain being less than that of the A alpha and gamma chains. The sequence of events which lead to the assembly of fibrinogen was deduced by determining the appearance of the radioactive chains in each of the fibrinogen precursors and in fibrinogen at various times during a pulse-chase incubation. Fibrinogen assembly commences while nascent incomplete B beta chains are attached at polysomes. Preformed A alpha and gamma chains, drawn from the intracellular pool, combine independently to the growing B beta chains. On completion of the nascent B beta chains, newly formed B beta-A alpha and B beta-gamma complexes are released from the polysomes and enter the luminal space of the endoplasmic reticulum. Later other A alpha and gamma chains are added by ordered disulfide interaction, leading to the eventual formation of dimeric fibrinogen.

Intracellular assembly of human fibrinogen

Hep-G2 cells, pulse-labeled with L-[35S]methionine, incorporate radioactivity within 2 min into precursor forms of fibrinogen and into fibrinogen. Pulse-labeled intracellular fibrinogen is first composed of radioactive B beta chains, followed by nascent A alpha chains. Radioactive gamma chains accumulate in the cells and later contribute, via intermediate forms, to the assembly of fibrinogen. Following a pulse-chase incubation with L-[35S]methionine, the radioactive composition of newly secreted fibrinogen also reflects the fact that there is a large intracellular pool of gamma chains.

A murine model of lip epidermal/mucosal reactions to X-irradiation

A new radiobiological test system has been developed for lip epidermal/mucosal reactions in mice. This is intended for use in investigations of the effect of non-standard fractionation and of modifying drugs on oral radiation reactions in human cancer patients. An arbitrary scale of scores was devised, with separate scores for oedema of the lips and for erythema or exudation. After single doses of 13-20 Gy, the mouse lip epidermal reactions began at 5 days, reached a peak about 10-13 days, and had fallen to low values, but not to zero, by 21 days. Several different periods for averaging the reaction scores were tested for relative steepness and variability, the most useful being 10-12 days inclusive or the 12th day score alone. The use of longer periods of averaging led to apparent saturation of the scores. It was found that large doses of X-rays repeated at 21-23 day intervals did not lead to escalating waves of reactions unless each dose was greater than 17 Gy. With these larger doses, escalation of reactions occurred even if the intervals were extended.

Bovine pulmonary surfactant: chemical composition and physical properties

Bovine pulmonary surfactant was obtained by endotracheal lavage of lungs from newly slaughtered cows followed by differential centrifugation. Lipid extracts of bovine surfactant contained 3% neutral lipid, mainly as cholesterol and diacylglycerol and 97% phospholipid. Phosphatidylcholine (79%) and phosphatidylglycerol (11%) accounted for most of the phospholipids with smaller amounts of phosphatidylethanolamine, phosphatidylinositol, lyso-bis-phosphatidic acid and sphingomyelin. Fatty acid analysis revealed high levels of palmitate in phosphatidylcholine and to a lesser extent phosphatidylglycerol, but not in the other diacylphospholipids. Phosphatidylcholine was 53% disaturated and phosphatidylglycerol was 23% disaturated. Monoenoic species accounted for the major proportion of the remaining lipid. The protein content was 10% as estimated by the Lowry procedure and 5% when determined by amino acid analysis. Extraction with chloroform/methanol removed ca. 90% of the protein but had no effect on the surfactant properties as evaluated by a pulsating bubble technique.

Secretion of proalbumin by canavanine-treated Hep-G2 cells

The two processing sites in the conversion of preproalbumin to albumin are marked by arginine residues. Therefore, to study the mechanisms of albumin processing and secretion, the arginine residues of nascent albumin were replaced with canavanine by the incubation of Hep-G2 cells with this arginine analog. During a 4-h interval, canavanine inhibited (67%) the secretion of nascent albumin and increased the intracellular transit time of albumin secretion from 24 to 39 min. At 1 h, canavanine inhibited total protein synthesis by 19% and albumin synthesis by about 40%. Both the intracellular and secreted albumin produced by canavanine-treated cells were analyzed by DEAE-cellulose chromatography and were found to be more acidic than normal proalbumin and albumin. Further analysis on sodium dodecyl sulfate polyacrylamide gel electrophoresis indicated that the albumin produced and secreted by canavanine-treated cells appeared to have a larger molecular weight (by 4000) than serum albumin. The canavanine-treated cells were incubated with L-[3H]leucine and L-[3H]phenylalanine and the location of radioactive L-leucine and L-phenylalanine in the 30 NH2-terminal amino acid residues of secreted albumin was determined. The results indicated that canavanine-treated cells secreted proalbumin (79%) and also some fully processed albumin (21%). Preproalbumin was not secreted. Untreated Hep-G2 cells mostly secreted fully processed serum albumin (93%) with only traces of proalbumin (7%).

The role of mRNA competition in regulating translation. III. Comparison of in vitro and in vivo results

Competition of encephalomyocarditis virus, reovirus, and L-cell mRNAs for a message-discriminatory component was studied in vitro. The data were analyzed qualitatively to determine the relative initiation efficiencies among the various mRNAs. The effects of potassium chloride concentration, magnesium acetate concentration, and m7G methylation on mRNA competition in vitro were also studied. These results were correlated with translation rates in vivo for the same mRNAs, to determine if the sites of competition in vitro and in vivo are the same. It was found that under a particular set of magnesium acetate and potassium chloride concentrations, the order of mRNA initiation efficiencies was the same both in vivo and in vitro, suggesting that the same limiting message-discriminatory factor is regulating initiation rates in both cases. This can only be accomplished in a competitive situation when RNA is in molar excess relative to the discriminatory component.

Site of synthesis of metallothionein in rat liver

Free and membrane-attached polysomes were isolated from the liver of normal and cadmium-treated rats, and were translated using L-[35S]cysteine and a nuclease-treated reticulocyte lysate system. The translation products were analyzed for radioactive metallothionein by immunoprecipitation with antibodies to rat cadmium metallothionein followed by sodium dodecyl sulfate--polyacrylamide gel electrophoresis. In both normal and cadmium-treated rats, radioactive metallothionein was produced by free polysomes but not by membrane-attached polysomes. Cadmium treatment did not increase the in vitro ability of polysomes to synthesize metallothionein. As a control, the translation products of these two classes of polysomes were also analyzed for radioactive albumin and it was confirmed that membrane-attached polysomes produce albumin but do not synthesize metallothionein. The cell-free synthesis of metallothionein by free polysomes was also demonstrated by isolation of nascent metallothionein by Sephadex gel filtration and DEAE-cellulose chromatography. In adult rat liver there are two forms of metallothionein and both were produced in vitro by free polysomes.

Effect of cyclophosphamide on mice bearing methylcholanthrene-induced fibrosarcomas

Mice bearing large methylcholanthrene-induced fibrosarcomas lost the ability to respond in vitro to mitogen stimulation and to specifically neutralize autologous tumor cells in vivo. This depressed immune capability was due to active suppression, since spleen cells from advanced tumor-bearing mice could suppress the mitogen response of normal spleen cells and could inhibit tumor rejection when adoptively transferred to mice previously immunized against the tumor. Treatment with cyclophosphamide (CY) was found to affect the immune capability of the host, in addition to have a direct effect on the tumor. The number of cells in the lymph nodes and spleen, as well as their response to concanavalin A and lipopolysaccharide (but not phytohemagglutinin), decreased initially but returned to normal by Day 14. Most importantly, when CY was administered one day after tumor inoculation, the treated animals developed the ability to neutralize tumor at the same time as untreated controls but retained this capability as the tumors became advanced. Treatment with a single dose of CY as late as 11 or 20 days after tumor inoculation maintained or restored the tumor-neutralizing capacity of spleen cells. CY appears to alter the antitumor response of the host by inhibiting both cytotoxic and suppressor cells, but the cytotoxic cells recover rapidly, whereas the suppressor cells do not.

Soluble suppressor factor from the spleens of tumor-bearing mice

Spleen cells from tumor-bearing mice when cultured for 3 to 5 days released a soluble factor into the media that suppressed the stimulation of lymph node and spleen cells by tumor antigen or mitogens. Spleens from mice bearing MC43 tumors for 14 days were capable of producing suppressor factor in vitro, while those from mice bearing the tumor for 10 days or less failed to do so. Lymph node cells from the same animals did not produce suppressor factor in vitro. The suppressor factor was produced by a nonadherent cell population, was heat stable, was lost on dialysis, and did not appear to be tumor antigen or thymidine.

Stimulation of thymus- and bone marrow-derived lymphocytes by tumor cells in culture

In vitro lymphocyte stimulation by mitomycin-blocked tumor cells can be used to measure tumor-specific immune responses. In order to determine the responding cell type(s) in this reaction, lymph node and spleen cell populations were specifically depleted of thymus- or bone marrow-derived cells by the use of the appropriate antisera and complement or by immunoadsorption of the Fc receptor-bearing cells to antibody-coated sheep red blood cell monolayers. The compositions of both the original and the modified lymphocyte populations were determined by (a) viability counting following treatment with antisera and complement, (b) direct and indirect immunofluorescence, (c) antibody-coated erythrocyte rosette formation, and (d) response to thymus- and bone marrow-derived cell mitogens. In the lymph node cell populations, only the thymus-derived cells were stimulated by the tumor cells. However, both bone marrow- and thymus-derived cells from tumor-immune spleens underwent stimulation when exposed to tumor cells in culture.

Tumor-specific immune responsiveness of the tumor-bearing host

In vitro lymphocyte stimulation by mitomycin-C-blocked tumor cells has been used to demonstrate tumor-specific antigens in methylcholanthrene-induced sarcomas and in syngeneic murine systems, and to follow the evolution of tumor immunity in the tumor-bearing state. Lymphocytes from normal mice, from mice bearing small methylcholanthrene-induced tumors (less than 1 cm in diameter) and from tumor-immunized mice (which had been sensitized by tumor cell inoculation and subsequent tumor (removal) were stimulated by mitomycin-C-blocked tumor cells to undergo increased DNA synthesis in culture. However, lymph node cells from mice with large methylcholanthrene-induced tumors (greater than 1 cm in diameter) had quite different characteristics. The background DNA-synthetic activity of lymph node cells from tumor-bearing mice was much higher than that of lymph node cells from normal mice or from preimmunized, non-tumor-bearing mice, and progressively increased with the duration of tumor-bearing and the size of the tumor. Lymph node cells from mice bearing large tumours appeared to be maximally stimulated by the tumor in vivo and were incapable of further stimulation by the same tumor cells in vitro, but exhibited normal responses to other antigens and nonspecific mitogens. Lymph node cells from mice bearing large tumors depleted of the adherent cells had lower background levels of DNA synthetic activity per 10(6) cells and underwent stimulation similarly to lymphoid cells from preimmunized, non-tumor-bearing mice. Spleen cells from mice bearing large tumors also had increased background levels of DNA synthetic activity, but contrary to the observations made with the lymph node cells, they were able to undergo further stimulation when cultured with the same tumor cells. Studies on the background incorporation of tritiated thymidine by lymph node cells from tumor-bearing mice revealed that the spontaneous uptake of reconstituted populations was nearly that of the original population and more than twice that of the arithmetical sum of the nonadherent and the adherent subpopulations. This was not found with normal lymph node cells or with spleen cells from normal or tumor-bearing mice. The differential effects observed with lymph node cells compared to spleen cells from tumor-bearing mice are emphasized and possible explanations for these findings are discussed.

Altered thyroidal responsivity to thyrotropin induced by circulating thyroid hormones. A "short-loop" regulatory mechanism?

We studied the effect of thyroid hormone administration on responsivity of murine thyroid to exogenous thyrotropin (TSH) in order to explore the possibility that the thyroid gland might be directly inhibited by its own hormones. In the rat both L-thyroxine (T4) and 3,5,3'-L-triiodothyronine (T3) pretreatment inhibited TSH-induced thyroidal ornithine decarboxylase (ODC) activity in vivo in a dose-related manner (half-maximal inhibition, 1.7 mug/rat and 0.6 mug/rat, respectively). Other structurally related compounds exhibited the following inhibitory potencies compared to T4: T3, 283%; triiodothyroacetic acid, 40%; D-T4, 18%; 3,5-L-diiodothyronine, 9%. Monoiodotyrosine, diiodotyrosine, and iodide were not inhibitory. The full inhibitory effect of T4 or T3 was observed when thyroid hormone was administered from 96 to 12 h before TSH and was also seen in hypophysectomized animals. Pretreatment with T4 or T3 in divided doses over 2 1/2 days inhibited TSH-induced increase in [1-14C]glucose oxidation to 14C02 and [3H] leucine incorporation into protein in rat thyroid. In the mouse T4 or T3 pretreatment (0.25-25 mug daily) caused dose-related inhibition of both thyroidal ODC activity and 131I release induced by TSH in vivo. In mice on a low-iodine diet (LID) but not in animals on a regular diet (RD) NaI pretreatment also blunted TSH-induced thyroidal ODC activation and 131I release. When LID or RD mice were pretreated with 12.5-125 mug of T4 or T3 over 2 1/2 days, TSH-induced in vitro stimulation of thyroid cyclic 3',5'-adenosine monophosphate formation was inhibited in a dose-related manner; NaI pretreatment was inhibitory in the LID mouse only. Prior administration of exogenous TSH blunted the activation of thyroid ODC and thyroid hormone release induced by subsequent TSH administration in rat and mouse. These studies indicate altered thyroid responsivity to TSH under the influence of circulating thyroid hormones and suggest the existence of a "short-loop" negative feedback regulating thyroid function.

Regulation of thyroid ornithine ornithine decarboxylase (ODC) by thyrotropin. I. The rat

We studied the effects of TSH on rat thyroid ornithine decarboxylase (ODC) activity. After 1 day of goitrogen treatment, there was an abrupt fall in serum triiodothyronine (T3) a rise in circulating TSH, and a dramatic increase in thyroid ODC activity. Despite the continued rise in TSH and progressive increase in thyroid gland size with further treatment, thyroid ODC activity declined on the third day and remained at submaximal levels. Thyroid ODC activity was also stimulated in a dose-related manner by administration of exogenous TSH. Little TSH effect was noted before 3 h. Maximal ODC activity occurred between 4 and 5 h. The TSH stimulation of ODC could be inhibited by pretreatment with actinomycin D or cycloheximide, suggesting that the increase in ODC activity requires new RNA and protein synthesis. Although pretreatment with agents that alter microtubule structure (e.g., colchicine and vinblastine) prevent stimulation of ODC activity by TSH, additional data suggest, but do not confirm, that hrmone secretion and ODC activation may be dissociable. Further studies were undertaken to determine whether cyclic AMP (cAMP) or prostaglandins played any role in the regulation of thyroidal ODC activity. Dibutyryl cAMP, alone, or together with aminophylline, did not stimulate thyroidal ODC activity in dosages which concomitantly stimulated adrenal enzyme activity. Likewise, prostaglandin E2 (PGE2) did not stimulate thyroidal ODC activity, but did stimulate adrenal enzyme activity in a dose-related manner. However, pre-treatment of rats with inhibitors of prostaglandin synthesis prevented the activation of thyroidal ODC BY TSH. One inhibitor, indomethacin, attenuated the TSH stimulation of enzyme activity in a dose-related manner. Indomethacin pretreatment also resulted in approximately a 10-fold decrease in thyroidal prostaglandin levels. Exogenous PGE9, in dosages as high as 500 pg, did not overcome the inhibitory effect of indomethacin on ODC activation. Although the precise role for endogenous prostaglandins remains to be defined, it does appear that a reduction in thyroidal prostaglandins prevents activation of the enzyme by TSH.

Refractoriness of lymph-node cells from tumour-bearing animals

In vitro lymphocyte stimulation by mitomycin-C-blocked tumor cells has been used to demonstrate tumor-specific antigens in syngeneic murine systems and to follow the evolution of tumor immunity with the tumor-bearing state. Mitomycin-blocked tumor cells stimulated syngeneic lymphocytes from normal mice, from those bearing small tumors (less than 1 cm in diameter) and from tumor-immune mice, sensitized by tumor-cell inoculation and subsequent tumor removal, to undergo increased DNA synthesis as measured by the incorporation of tritiated thymidine. However, lymph-node cells from mice bearing tumors over 1 cm in diameter appeared to be maximally stimulated in vivo and incapable of further stimulation by the same tumor cells in vitro. This was reflected by the progressively increasing background levels of nucleic acid synthesis with the length of tumor-bearing and the size of the tumor. Although lymph-node cells from mice with large tumors did not respond to the same tumor cells in vitro, they did have normal responses to PHA. Within 7-14 days of surgical removal of the tumor, specific lymphocyte responsiveness and background activity returned to previous normal levels, but reinoculation with 10-6 tumor cells resulted in progressive tumor growth and loss of specific in vitro responsiveness when the second tumor had reached the critical size of 1 cm in diameter. Brief exposure of tumor-immune lymph-node cells to a soluble antigen extract of the same tumor resulted in a marked increase in DNA synthetic activity compared to that obtained after exposure to a different tumor extract, muscle extract or medium alone underwent stimulation when cultured with mitomycin-blocked tumor cells. However, normally responsive tumor-immune lymph-node cells, after brief exposure to a soluble antigen extract of the same tumor, initially underwent increased DNA synthesis, but were incapable of further stimulation by mitomycin-blocked tumor cells. Tumor antigen, alone or complexed with antibody, was also demonstrated in the sera of mice bearing large tumors and is thought to be responsible for the refractoriness of lymph-node cells from these mice to further stimulation in vitro. These experiments demonstrate that tumor size and the consequent antigen load to which the tumor-bearing animals is subjected have a profound effect on tumor-specific lymphocyte responsiveness.

Effect of various levels of isoflavone aglycone-enriched fermented soybean meal on redox status, serum hormones and milk quality in ewes

The study investigated the effects of various levels of isoflavone aglycone-enriched fermented soybean meal (FSBM) on the redox status, serum hormones and milk quality of ewes from late pregnancy to early lactation. Twenty Chongming White ewes were chosen and divided into four treatment groups (n = 5): basal diet without FSBM (CON); basal diet with 2% (FSBM2); 4% (FSBM4); and 6% FSBM (FSBM6) replacing equal amounts of soybean meal (SBM). At parturition, maternal serum, the placenta and colostrum were collected. At day 21 of lactation, maternal serum and milk were collected. Results showed that, compared with CON, feeding ewes with FSBM6 reduced the concentrations of hydrogen peroxide (H2O2) and 8-hydroxy-2-deoxyguanosine (8-OHdG), and increased the activity of superoxide dismutase (SOD) and total antioxidant capacity (T-AOC) concentration in the placenta. At parturition and day 21 of lactation, the serum SOD activity and T-AOC concentration in FSBM4 and FSBM6 were higher than those in CON. Furthermore, the concentration of serum 8-iso prostaglandin (8-ISO-PGF2α) was markedly lower in FSBM6 than in CON. Serum prolactin (PRL), insulin-like growth factor 1 (IGF-1) and epidermal growth factor (EGF) concentrations were increased in FSBM4 and FSBM6 compared with CON. PRL concentration was increased in FSBM2. FSBM4 increased the levels of fat, protein, lactose, IgA, IgG and IgM in colostrum and milk. In conclusion, feeding ewes with FSBM from late pregnancy to early lactation seemed to increase maternal and placental anti-oxidative capacity, and improve serum hormones and milk quality. Considered overall, the level of 4% supplementation is recommended.Keywords: Milk contents, oxidative stress, placenta, serum parameters