Cholinergic amacrine cells are not required for the progression and atropine-mediated suppression of form-deprivation myopia

Expression of extracellular matrix (ECM) components during differentiation of pre-existing preadipocytes and preadipocytes recruited by dexamethasone (DEX) was examined with immunocytochemistry in primary cultures of adipose tissue stromal vascular (S-V) cells. Immunocytochemistry showed that a small proportion of preadipocytes (AD-3+) in 24-h cultures (d 0 to 1) contained lipid or expressed ECM. Two days of insulin treatment markedly increased preadipocyte ECM expression, and preadipocytes were "rounder" than those not treated with insulin. Dexamethasone with insulin increased preadipocyte recruitment two- to fivefold in completely serum-free cultures and in cultures serum-free after seeding and plating in serum for 1 to 3 d. Double staining demonstrated that ECM expression and lipid accretion were tightly coupled and lagged significantly behind preadipocyte recruitment (AD-3 expression). Double staining (lipid and AD-3) also demonstrated remarkable and unexpected cytological traits indicating a "reticuloendothelial" nature of newly recruited preadipocytes. Time-lapse phase contrast microscopy verified these observations and demonstrated that small adipocytes and preadipocytes migrated and formed cell-to-cell contacts while aggregating and clustering. Large clusters of lipid-free preadipocytes developed in DEX-treated cultures, but not in cultures treated with DEX + insulin. However, the influence of DEX on preadipocyte recruitment and ECM expression was independent of insulin. Preadipocytes on ECM substrata accumulated lipid but were "flat" and did not express ECM components, regardless of insulin or DEX treatment. These studies clearly indicate that preadipocytes express ECM components after recruitment, and the ECM may be critical for morphological development of adipocytes.     

New physiological importance of two classic residual products: carbon monoxide and bilirubin

The relationship between obese (ob) gene expression and preadipocyte differentiation was examined in primary cultures of porcine stromal-vascular (S-V) cells by Northern-blot analysis using a pig ob cDNA probe. Isolated adipocytes expressed high levels of ob gene, but S-V cells did not express the ob gene. Cultures were seeded with fetal bovine serum (FBS) plus dexamethasone (Dex) for 3 days followed by ITS (insulin 5 microg/ml, transferrin 5 microg/ml, and selenium 5 ng/ml) treatment for 6 days. Detectable levels of ob mRNA first appeared at day 1 with very low activity of glycerol phosphate dehydrogenase (GPDH). Levels of ob mRNA increased in parallel with preadipocyte number or GPDH activity at the later times in cultures. The depletion of preadipocytes by complement-mediated cytotoxicity at day 3 of culture resulted in markedly decreased ob mRNA expression. Immunocytochemical analysis showed that ob protein was localized in the cytosol of preadipocytes and adipocytes. These data indicated that the ob gene is expressed by preadipocytes and ob gene expression may be correlated with preadipocyte recruitment as well as fat cell size.     

Calculated magneto-optical Kerr effect in Fe, Co, and Ni

To examine whether GH and IGF-I participate in the regulation of obese (ob) mRNA expression we determined ob mRNA levels in epididydimal fat pads of hypophysectomised (hypox) rats, hypox rats treated with recombinant human (rh) GH or rhIGF-I and normal, weight-matched controls. We found that 1. ob mRNA was markedly suppressed after hypophysectomy (37 +/- 25% of controls), 2. GH infusion had no effect on ob mRNA, but stimulated IGF-I mRNA in fat pads, 3. IGF-I treatment further suppressed ob mRNA (3.5% +/- 0.6% of controls) and 4. serum insulin levels were decreased in all hypox groups (11.2 to 15.9% of controls). In conclusion, exogenous and GH-induced IGF-I differ in their effects on ob mRNA expression and GH is unable to restore ob mRNA towards normal at low insulin levels.     

Retroperitoneal malignant mesenchymoma: imaging findings in five cases

This study documented the effects of conjugated linoleic acid (CLA) on the proliferation and differentiation of 3T3-L1 preadipocytes. During proliferation, preadipocytes were cultured in Dulbecco's modified Eagle's medium (DMEM), 100 g/L fetal bovine serum (FBS), 0. 584 g/L L-glutamine and 0 (control), 0.5, 1.0, 5.0 or 10.0 mg/L CLA. Proliferation of 3T3-L1 preadipocytes was measured directly by cell counting and indirectly by radiolabeled thymidine incorporation into DNA at 96 h postinoculation. Conjugated linoleic acid was not cytotoxic during proliferation or differentiation. The 0.5, 1.0, 5.0 or 10.0 mg/L CLA treatments inhibited proliferation by 8, 12, 31 and 36%, respectively (all P < 0.05). Treatment with 10 mg/L CLA or 10 mg/L linoleic acid (cis-9,12) reduced the incorporation of 3H-thymidine into DNA by 56 and 35%, respectively, suggesting that some portion of the effect of CLA on preadipocyte proliferation was nonspecific. After the initiation of differentiation, preadipocytes were cultured in DMEM, 100 g/L FBS, 0.584 g/L L-glutamine, 1.7 micromol/L insulin and 0 (control), 0.5, 1.0, 5.0 or 10.0 mg/L CLA. Radiolabeled glucose incorporation into cellular lipids was increased from 7.4 to 11.1, 11.1, 17.4 and 22.5 nmol/(h.10(6 )cells) (all P < 0.05) by 0.5, 1.0, 5.0 and 10.0 mg/L CLA, respectively. A media concentration of 10 mg/L CLA increased total cellular CLA (from 0 to 0.16 +/- 0.01 micromol/10(6 )cells), palmitic acid (from 0.47 to 1.10 +/- 0.03 micromol/10(6 )cells) and palmitoleic acid (from 0.24 to 0.81 +/- 0.03 micromol/10(6 )cells) (means +/- pooled SEM; all P < 0.05). Conjugated linoleic acid had no effect on arachidonic acid content, but decreased its proportion (g arachidonic acid/100 g total fatty acids) by >50% (P < 0.05). These data indicate that CLA inhibited proliferation and promoted de novo lipogenesis and lipid filling in 3T3-L1 preadipocytes, suggesting that CLA may reduce overall fat accumulation in growing animals by inhibiting stromal vascular preadipocyte hyperplasia.     

Parotid gland tissue is able partially to assume pituitary functions under the influence of hypothalamic factors: in vivo and in vitro studies

To test whether salivary tissue can secrete pituitary hormones, female Sprague-Dawley rats were hypophysectomized (hypox) and the following were transplanted to the sella turcica: parotid gland (group 3, n=33), adrenal gland (group 4, n=30), muscle (group 5, n=24). Group 2 (n=21) had the sella turcica filled with dentist's cement. In addition a group of rats (group 1, n=22) remained intact as controls. All groups were followed for 8 months. Daily vaginal smears showed normal cyclicity in controls and constant dioestrus in all hypox groups. Blood samples, taken once every 30 days before and after LHRH stimulation, showed significantly lower (P<0.001) plasma LH values in all hypox groups compared with controls. In group 3, a gradual and significant increase (P<0.05) was observed in the LH response to LHRH in parallel with a partial recovery of oestrous smears. No LH modification was observed in the other hypox groups. Plasma prolactin (PRL) levels were also very low in all hypox groups and were unaltered throughout the study. At the end of the experiments, half the animals were killed by decapitation and the hypothalamic-pituitary areas carefully dissected, homogenized and analysed for LH and PRL content. The remaining animals were perfused with 4% paraformaldehyde to obtain fixing of the whole body tissues. Hypothalamic and transplant areas were carefully dissected, frozen, cut and submitted to immunochemical procedures. LH content in the graft of group 3 animals was markedly (P<0.001) lower than in the control pituitary, but significantly higher (P<0.05) than in the other hypox groups. Immunochemistry showed LH and PRL positive cells in the graft of group 3 animals, whereas neither positive cells, nor LH content were observed in the parotid gland in situ. Experiments were completed with in vitro cultures of parotid glands in the presence or absence (controls) of synthetic hypothalamic hormones or rat hypothalamic extracts. After 1.5 weeks of culture, a significantly higher LH concentration (P<0.05) was observed in the wells treated with synthetic hypothalamic hormones (216+/-46 pg/ml vs 41+/-6 pg/ml in controls). When hypothalamic extracts were used, the LH levels increased more markedly (1834+/-190 pg/ml vs 36+/-6 pg/ml in controls) and those values were maintained during 3 weeks of culture. Immunostaining of these cultures showed a positive LH reaction in the epithelial cells found in the hypothalamic extract-treated wells. Both in vivo and in vitro studies confirm the transdifferentiation of parotid gland tissue to pituitary hormone-producing cells under hypothalamic influence.     

Influence of methylprednisolone and transforming growth factor-beta on wound healing

This study was aimed at evaluating the influence of transforming growth factor-beta (TGF-beta) on methylprednisolone induced inhibition of wound healing. C57BL/6 mice underwent a standardized dorsal incision. At regular intervals after wounding the mice were sacrificed and their pelts were excised. The fresh breaking strength (FBS) of the pelts was then measured with a constant-speed tension meter. 1) In the first experiment, designed to determine if methylprednisolone did in fact have any inhibiting effect on wound healing, mice received methylprednisolone and a control group received saline. Both methylprednisolone and saline were administered for a four day period. In this experiment the FBS of methylprednisolone treated mice was weaker than that of the control group on the 14th and the 21st day. 2) In the second experiment, designed to determine when the administration of methylprednisolone most noticeably inhibited wound healing, mice were divided into three groups which received methylprednisolone in the following manner: for three days prior to wounding, on the day of wounding, and for three days immediately following wounding. The fourth group received no methylprednisolone at all. The FBS of mice treated with methylprednisolone for three days prior to wounding was weaker than that of the control group on the 14th day after wounding, but showed no significant difference on the 21st day after wounding. The FBS of mice treated on the operative day was weaker on both the 14th and the 21st day after wounding. The FBS of mice treated three days after wounding showed no significant difference on the 14th day after wounding, but was weaker than the control group on the 21st day after wounding. 3) In the third experiment, designed to determine at what time the administration of TGF-beta most accelerated wound healing, mice were divided into three groups which received TGF-beta at different intervals. The first group received TGF-beta on the day of wounding, the second group received TGF-beta on the third day after wounding, and the third group received TGF-beta on the 7th day after wounding. A control group received no treatment. In this experiment the FBS of mice treated with TGF-beta on the third day after wounding was stronger than that of the control group when measured on the 7th and 11th day after wounding, but there was no significant difference on the 14th day. The FBS of mice treated on the day of wounding and mice treated on the 7th day after wounding was not significantly different from that of the control group. 4) In the fourth experiment, designed to determine if TGF-beta can prevent methylprednisolone-induced inhibition of wound healing, mice were divided into three groups. The first group received methylprednisolone for four days prior to wounding. On the third day after wounding they were given saline. The second group also received methylprednisolone for four days prior to wounding, but was treated with TGF-beta on the third day after wounding. The third group received no methylprednisolone, and was given saline three days after wounding. In this experiment the FBS of mice which received only methylprednisolone and saline was weaker than that of the control group on both the 14th and the 21st day after wounding. However, there was no significant difference between the FBS of methylprednisolone treated mice which received TGF-beta and the control group on both the 14th and the 21st day after wounding. From these results the following conclusions were drawn: 1) Methylprednisolone does inhibit wound healing. 2) The influence of methylprednisolone on wound healing is stronger if it is received on operative day. 3) TGF-beta can accelerate wound healing. 4) TGF-beta can prevent methylprednisolone induced inhibition of wound healing.     

EI-1511-3, -5 and EI-1625-2, novel interleukin-1 beta converting enzyme inhibitors produced by Streptomyces sp. E-1511 and E-1625. I. Taxonomy of producing strain, fermentation and isolation

The culture conditions which are able to support the differentiation of bovine intramuscular (i.m.) stromal-vascular (S-V) cells into adipocytes were investigated. Bovine i. m. S-V cells were able to undergo adipose conversion, assessed by emergence of lipid droplets and induction of glycerol-3-phosphate dehydrogenase (GPDH) activity, when treated with 0.25 microM dexamethasone and 0.5 mM 1-methyl-3-isobutylxanthine in a serum-deprived (0.1%) medium containing 850 nM insulin and 1 mM octanoate. Octanoate was essential for morphological differentiation and addition of 25 microM of cholesterol with octanoate induced higher GPDH activity. The differentiation of the cells was not observed in the medium containing 10% fetal calf serum which supported the cell proliferation of undifferentiated cells even after confluence. Similarly, both bovine brain extracts and muscle extracts inhibited the differentiation of S-V cells in the serum-deprived condition. These results suggest that the existence of lipids such as octanoate and the process of growth-arrest in preadipocytes and/or other cells are necessary for the differentiation of bovine S-V cells into adipocytes in culture.     

Intraamniotic ethyl docosahexaenoate administration protects fetal rat brain from ischemic stress

Studies were conducted on the prenatal rat given a single intraamniotic injection of ethyl docosahexaenoate (Et-DHA; 9.6-12 mmol per fetus) or subjected to an n-3 fatty acid-deficient diet to assess the role of docosahexaenoate on oxidative stress during episodes of ischemia. A time-dependent decrease in the ability of brain slices from animals treated with Et-DHA to produce thiobarbituric acid-reactive substance (TBARS), most pronounced after 1 day (from 58.1 +/- 4.22 to 15.9 +/- 1.6 nmol/mg of DNA), was noticed on stimulation with Fe2+. Brain slices from fetuses treated for 1 day with Et-DHA and those from untreated fetuses produced TBARS levels of 46.7 +/- 6.5 and 114.8 +/- 10.8 nmol/mg of DNA, respectively, after a 20-min occlusion of the fetal-maternal circulation at embryonic day 20, suggesting a protective effect of Et-DHA. The protective effect of a single dose of Et-DHA in utero remained high up to 3 days after injection (p < 0.001) and was long-lasting, yet not significant, up to 3 days following birth. In agreement with a reduction in TBARS production by slices, the endogenous levels of TBARS in brains of Et-DHA-treated animals were lower than in the controls. Et-DHA-injected fetuses exhibited significantly higher levels of esterified DHA than the noninjected controls. n-3-deficient diet given to dams for 2 weeks before birth did not affect the levels of TBARS production in control fetal brain slices but abolished the increase caused by ischemia. Et-DHA administration for 24 h to n-3-deficient fetuses reduced the amount of TBARS produced by the fetal brain slices from 49.1 +/- 8.5 to 31.7 +/- 4.1 nmol/mg of DNA. A protective effect from oxidative damage after postischemic oxidative stress in fetal brain following DHA supplements is suggested, whereas the effect of n-3 fatty acid deficiency in this regard is more ambiguous.     

Hospital-based patient information services: a model for collaboration

Studies about bone formation and regulation are complex due to a close relationship between bone cells. Primary cell cultures allow to understand osteoblastic function. We isolated cells from the cortical metacarpal bone of 85 or 120 day-old ovine fetuses by an enzymatic method. After first passage and cell amplification, the growth medium (DMEM, ascorbic acid and fetal calf serum 10%) was replaced at confluence by a mineralization medium (MM: DMEM, ascorbic acid, beta-glycerophosphate, insulin). Alkaline phosphatase (ALP) activity in cell-matrix layer increased after 4 days of cultures in MM and maximized at day 6. We also measured osteocalcin, ALP and IGF-I secretion simultaneously during mineralization. PTH, PTHrP and 1.25(OH)2D3 decreased ALP activity in cell-matrix layer after 4 days of treatment in MM without fetal calf serum (FCS). Cells from 120 day-old fetuses were cultivated in MM with 10% FCS during 32 days to induce mineralization. Inorganic phosphorus concentration increased in medium between days 5 and 12, Ca concentration decreased in medium after 12 days of culture. Mineralization started at day 12, in the same time ALP activity appeared in medium. Osteocalcin secretion increased between days 6 and 12, decreased at day 14 and increased from day 16 until day 32. Ovine fetal bone cells produced IGF-I until first days of culture in MM. Such ovine osteoblast phenotype cells having the capacity to differentiate and mineralize in vitro would be a model to study the endocrine regulation of osteoblastic function in large mammals.     

Potentiation of the antitumor effect of ionizing radiation by brief concomitant exposures to angiostatin

Angiostatin, a proteolytic fragment of plasminogen, inhibits the growth of primary and metastatic tumors by suppressing angiogenesis. When used in combination with ionizing radiation (IR), angiostatin demonstrates potent antitumor synergism, largely caused by inhibition of the tumor microvasculature. We report here the temporal interaction of angiostatin and IR in Lewis lung carcinoma (LLC) tumors growing in the hind limbs of syngeneic mice. Tumors with an initial mean volume of 510 +/- 151 mm3 were treated with IR alone (20 Gy x 2 doses on days 0 and 1), angiostatin alone (25 mg/kg/day divided twice daily) on days 0 through 13, or a combination of the two as follows: (a) IR plus angiostatin (days 0 through 13); (b) IR plus angiostatin (days 0 and 1); and (c) IR followed by angiostatin beginning on the day after IR completion and given daily thereafter (days 2 through 13). By day 14, tumors in untreated control mice had grown to 6110 +/- 582 mm3, whereas in mice treated with: (a) IR alone, tumors had grown to 2854 +/- 338 mm3 (P < 0.05 compared with untreated controls); and (b) angiostatin alone, tumors had grown to 3666 +/- 453 mm3 (P < 0.05 compared with untreated controls). In combined-treatment groups, in mice treated with: (a) IR plus longer-course angiostatin, tumors reached 2022 +/- 282 mm3 (P = 0.036 compared with IR alone); (b) IR followed by angiostatin, tumors reached 2677 +/- 469 mm3 (P > 0.05 compared with IR alone); and (c) IR plus short-course angiostatin, tumors reached 1032 +/- 78 mm3 (P < 0.001 compared with IR alone). These findings demonstrate that the efficacy of experimental radiation therapy is potentiated by brief concomitant exposure of the tumor vasculature to angiostatin.     

Down-regulation of hepatic and renal 11 beta-hydroxysteroid dehydrogenase in rats with liver cirrhosis

Twenty-four crossbred primiparous sows were used to investigate the influence of insulin administration after weaning on the intrafollicular insulin-like growth factor i (IGF-I) system. Sows received 0.4 i.u. insulin kg-1 bodyweight or an equivalent volume of saline for 3 days (n = 5 insulin; n = 4 saline) or 5 days (n = 5 insulin; n = 6 saline) after weaning or served as untreated controls on day 1 (n = 4). The number and diameters of ovarian follicles were recorded, and fluid was aspirated from the 20 largest follicles for determination of oestradiol and IGF-I by radioimmunoassay and of insulin-like growth factor-binding proteins (IGFBPs) by western ligand blotting. The walls of the follicles were collected for mRNA analysis by RNase protection assay or granulosa cells were collected for estimation of apoptosis by flow cytometry. Insulin treatment resulted in smaller diameters of all follicles (P < 0.05) and tended (P < 0.07) to increase the number of follicles available on day 5 compared with saline-treated animals (19.8 versus 17.8). The concentration of oestradiol in follicular fluid from large (7-10 mm) follicles on days 3 and 5 was reduced (treatment by size class interaction; P < 0.05) by insulin treatment. Insulin also reduced intrafollicular concentrations of IGF-I at days 3 and 5 after weaning (treatment by day interaction; P < 0.02) while the amounts of IGFBP-3 and IGFBPs of molecular mass 30 and 22 kDa decreased from day 3 to day 5 in saline-treated animals only (treatment by day interaction; P < 0.05). Gene expression for IGF-I increased in saline-treated animals but decreased fourfold in insulin-treated sows from day 3 to day 5 (treatment by day interaction; P < 0.002). Gene expression for IGFBP-d decreased (P < 0.04) from day 3 to day 5, while expression of IGFBP-2 was unaffected by treatment or day. Overall, insulin influenced the IGF-I system in a manner consistent with slowing follicular growth and possibly allowed more follicles to become available for ovulation.     

Expression of CD54 (intercellular adhesion molecule-1) and the beta 1 integrin CD29 is modulated by a cyclic AMP dependent pathway in activated primary rat microglial cell cultures

Integrins mediate cell attachment to a variety of extracellular matrix proteins. These interactions play an important role in morphogenesis and differentiation. The mediating functions of integrins during chondrogenesis in vitro were investigated by using mesenchymal cells from limb buds of day 12 mouse embryos. The cells were treated with anti-beta 1, -alpha 1, and -alpha 5 integrin antibodies (a) from day 1 to day 3 and (b) from day 3 to day 7 of cultivation. The total culture period was 7 days. The presence of exogenous anti-beta 1, but not -alpha 1 and -alpha 5 integrin antibodies, from day 1 to 3 completely inhibited the differentiation of blastemal cells to chondroblasts and the formation of cartilage matrix. On the other hand, the presence of exogenous anti-beta 1, -alpha 1, and -alpha 5 integrin antibodies from day 3 of cultivation onwards had no effect. Immunoblotting and immunomorphological findings in the cultures treated with anti-beta 1 antibody from day 1 to day 3 revealed a pattern of integrins and collagen composed of beta 1, alpha 1, alpha 5 beta 1 integrins and collagen type I. The cartilage-specific chondroitin sulfate proteoglycan (CSPG) could not be demonstrated in these cultures. The cultures treated later (day 3 to day 7) showed a pattern of beta 1, alpha 3, alpha 5 beta 1, and alpha v beta 3 integrins, collagen types I and II, and CSPG identical to that of the untreated controls. These findings indicate that beta 1-integrins play a crucial role in early cartilage differentiation and point to a possible important cell-matrix interaction in the induction of chondrogenesis.     

Effects of incremental cortisol and adrenalectomy on plasma corticosteroid binding capacity in fetal sheep

The effects of incremental cortisol infusion or fetal adrenalectomy on plasma corticosteroid-binding capacity (CBC) were examined in sheep fetuses during late gestation (term approximately 150 days). Cortisol, infused from day 120 at 1.5 mg/day for the first 3 days, 2.5 mg/day for the next 5 days, and 3.5 mg/day for the final 2 days, stimulated a significant rise in plasma CBC and immunoreactive corticosteroid binding globulin (CBG). There was a significant positive correlation between individual values for total plasma cortisol concentrations and CBC values. In contrast, fetal adrenalectomy at day 115 prevented the rise in plasma CBC found in intact fetuses at term. These experiments show that exogenous cortisol, given in a manner that mimics the prepartum rise in fetal plasma cortisol, stimulates CBG biosynthesis, whereas abolition of the cortisol rise prevents the increase in CBG. The study provides strong support for the proposal that the prepartum increase in CBG biosynthesis in fetal sheep occurs in response to the progressive rise in adrenal cortisol output by the fetus towards term.     

Reproduction and fetal development in mice chronically exposed to nitrous oxide

The effects of exposure to nitrous oxide on reproductive indices, fetal development, and male fertility were examined in Swiss/ICR mice. In experiment I, female mice were exposed for 4 hours per day on days 6-15 of pregnancy, to 0.5% (5,000 ppm), 5.0% (50,000 ppm), or 50% (500,000 ppm) nitrous oxide. Control mice were untreated, exposed to compressed air, or treated with retinoic acid on day 8 of gestation. In experiment II, male mice were treated, as above, for 9 weeks and then mated nightly for 7 nights to untreated, virgin females. In experiment I, 1,761 fetuses from 154 dams were examined and found to be without evidence of adverse nitrous oxide treatment effects. In experiment II there were no differences among the groups in the ability of males to impregnate females or in litter size, fetal wastage, or fetal size. When we compare nitrous oxide with other inhalation anesthetics we have studied employing a similar protocol, we find the order of reproductive toxicity to be: halothane greater than enflurane greater than methoxyflurane greater than nitrous oxide. None of the agents were toxic, however, at the trace concentrations usually found in operating rooms.     

Unmasking large and persistent reductions in proliferation rate of aging cells

We have reported that nontransformed sublines of NIH 3T3 cells that are incubated under the growth constraint of confluence for 10 d or longer exhibit heritable reductions of growth rate upon serial subculture at low density, which simulate the effects of aging in vivo on cell growth. There is also a marked increase in the likelihood of neoplastic transformation. After switching to a new batch of calf serum (CS), we found the reduced growth rate was no longer produced within the previously established timeframe. However, substitution of fetal bovine serum (FBS) for CS during the period of recovery from confluence or the following tests of growth rate resulted in profound inhibition of growth in cells serially subcultured from confluent cultures. In some cases, fewer than one in a thousand cells from subcultures of confluent cultures formed colonies in FBS although they cloned at relatively high efficiency in CS. The reduced growth in FBS was retained in the postconfluent subcultures after many generations of multiplication at low density in CS. Generally, similar results with individual variations were obtained with three other batches of FBS. The numbers of cells per 3-d colony initiated from subcultures of confluent cultures were lower than those of control cultures that had never been confluent. Supplementation of FBS-containing medium with CS fully restored the growth of the postconfluent subcultures to the rate in CS medium, indicating that there is a deficiency of growth factor(s) in FBS rather than the presence of an inhibitor. The results show that prolonged incubation at confluence induces a populationwide heritable increase in requirement for growth factor(s) in short supply in FBS. Because clonal studies have shown that the reduction in growth rate is irreversible and varies in degree from clone to clone, we propose it arises from damage to DNA at any of many different genetic loci or from chromosome aberrations. Such genetic damage is also consistent with the increased tendency for neoplastic transformation in subcultures from the long-term confluent cultures.     

Prenatal cocaine, alcohol, and undernutrition differentially alter mineral and protein content in fetal rats

Alcohol exposure and undernutrition during pregnancy have been associated with altered fetal body composition. Recent observations suggest that cocaine exposure during pregnancy may impair delivery of nutrients to the fetus and could thereby alter body growth and composition. Such effects are important because they can adversely influence physical and neural development. Consequently, we investigated the dose-dependent effects of cocaine on fetal body composition in an animal (rat) model and compared such effects with those caused by prenatal alcohol exposure and undernutrition. Pregnant Sprague-Dawley rats received either 20, 30, 40, or 50 mg/kg cocaine HCl (SC) twice daily from gestation days 7 through 19. Pair-fed (undernutrition) and untreated control groups and a group receiving 3.0 g/kg alcohol (PO) twice daily served as comparison groups (n = 11 to 14/group). Females were sacrificed on gestation day 20. One male and one female fetus was removed from each dam. The fetuses were minced, dehydrated, defatted, and analyzed for content of protein and the minerals Zn, Ca, Fe, Mg, K, and Na. In terms of concentration per unit of fat-free dry solids, male fetuses in the cocaine groups showed significant decreases in protein compared to untreated controls (15+/-3 to 20+/-2 mg/g vs. 24+/-4 mg/g, p = 0.01). There was a significant treatment effect for Ca (p < 0.05), reflecting a trend for decreased Ca concentrations in the fetuses of the cocaine and undernutrition groups. Male fetuses in the alcohol group had significantly elevated Mg levels compared to male fetuses in the other groups (3.0+/-0.8 vs. 1.0+/-0.2 to 2.3+/-0.7 mg/g, p < 0.05). There were some sex differences, with female fetuses having significantly lower concentrations of Mg, Fe, K, and higher protein concentrations than male fetuses. Although the effects were few and modest, these results suggest that prenatal cocaine, alcohol, and undernutrition can differentially alter fetal body weight and composition and, therefore, adversely influence fetal development.     

Tacrine use in nursing homes: implications for prescribing new cholinesterase inhibitors. SAGE Study Group. Systematic Assessment of Geriatric Drug Use via Epidemiology

The present study evaluates the physiological effects of magnetic stimulation on astrocyte cultures. Cell cultures were exposed to pulsed magnetic stimulation (10 Hz, 10 sec) at the following levels: 0.10 tesla (T; Group A); 0.21 T (Group B); 0.42 T (Group C); and 0.63 T (Group D). Glial fibrillary acidic protein (GFAP) levels from immunoblots, total protein concentrations, and cellular morphology were analyzed at 0, 1, 3, 5, 7, 13, and 20 days poststimulation. Significantly higher GFAP levels were observed in Group D at day 3 (P = 0.0114). The change was transient as the GFAP levels quickly returned to control levels by day 5. No other significant changes in GFAP levels were observed. In comparison to control protein levels at day 0, concentrations from Groups B, C, and D were significantly lower (P < 0.006), whereas at day 3, Groups C and D were significantly higher (P < 0.02). Differences in astrocyte morphology due to magnetic stimulation were not observed. This study demonstrated that high intensity magnetic stimulation for only 10 sec induced a transient biological response.