Abnormally high nourishment during sensitive periods results in body weight changes across generations

OBJECTIVE

This study asked whether a brief period of overnutrition during a developmentally sensitive time could impact the individual's adult weight and that of succeeding generations.

RESEARCH METHODS AND PROCEDURES

Female rat pups (F1 generation) were randomly assigned to 1 of 3 groups: (1) a control group that was naturally reared by mothers; (2) another control group implanted with chronic gastric fistulas on postnatal day 4 and fed enough formula to match the growth of the mother-reared group; and (3) an experimental group gastrostomized and infused from day 8 through day 16 with a greater quantity of food than gastrostomy-reared controls (OF). On postnatal day 16, both gastrostomy-reared groups were returned to normal litters. Adult F1 females from overfed and mother-reared groups were bred with normal males to yield an F2 generation. F2 adult females were bred to normal males to produce an F3 generation.

RESULTS

When adult, the F1 experimental group was heavier than control groups. F2 adults from OF mothers were smaller than those from the control group. F3 animals from OF grandmothers were heavier at weaning than F3 descendants from mother-reared animals.

DISCUSSION

Excess nourishment during a developmentally sensitive period changed the metabolic phenotype of one generation so dramatically that the gestational development and subsequent phenotype of two succeeding generations were also changed. The experiment models fetal effects of gestational diabetes in humans and may help to elucidate how, independent of genetic anomalies, secular changes can be detected across generations.

Coexpression of dopamine D1 and D3 receptors in islands of Calleja and shell of nucleus accumbens of the rat: opposite and synergistic functional interactions

Using double in situ hybridization, we found extensive coexpression of dopamine D1 and D3 receptor (D1R and D3R) mRNAs in neurons of the island of Calleja major (ICjM) and ventromedial shell of nucleus accumbens (ShV), respectively. Thus, at least 79 and 63% of D3R mRNA-expressing neurons in ICjM and ShV also expressed the D1R mRNA. Coexpression of D1R and D3R mRNAs was found to occur in substance P (SP) mRNA-expressing neurons in both areas, suggesting SP mRNA as a marker of the activity of coexpressing neurons. Administration of SKF 38393, a D1R receptor agonist, increased c-fos mRNA in ICjM, whereas administration of quinpirole, a D2R/D3R agonist, decreased it; SCH 23390, a D1 R antagonist and nafadotride, a preferential D3R antagonist, given alone, had effects opposite to those of the corresponding agonists. These data indicate that basal c-fos expression in ICjM is maintained by endogenous dopamine acting tonically upon two receptor subtypes subserving opposite effects on the same cell. However, in ShV, whereas SKF 38393 also increased c-fos mRNA, quinpirole had no effect, a difference presumably reflecting the lower fraction of neurons coexpressing D1R and D3R in this area. In contrast, in ShV from reserpine-treated rats, SKF 38393 increased SP mRNA and quinpirole potentiated this effect. These contrasting interactions of D1R- and D3R-mediated signalling events, i.e. in either opposite or synergistic directions, most likely occurring at the single cell level, may serve to increase the dopamine response threshold of the target cells in ICjM and to maintain a strong tonic activity of ShV neurons.

Functional implications of multiple dopamine receptor subtypes: the D1/D3 receptor coexistence

The D3 dopamine receptor, a D2-like receptor, is selectively expressed in the ventral striatum, particularly in the shell of nucleus accumbens and islands of Calleja, where it is found in medium sized substance P neurons. The latter co-express the D1 receptor whose interaction with the D3 receptor was studied by treating rats with selective agonists and antagonists. In agreement with the opposite cAMP response, they mediate in cultured neuroblastoma cells, the D1 and D3 receptors exerted opposite influences on c-fos expression in islands of Calleja. However, in agreement with the synergistic influence of cAMP on D3 receptor-mediated mitogenesis on the same cultured cells, D1 and D3 receptor stimulation in vivo synergistically enhanced preprotachykinin mRNA in the shell of accumbens. This indicates that the two receptor subtypes may affect neurons in either synergy or opposition according to the cell or signal generated. Levodopa-induced behavioral sensitization in hemiparkinsonian rats is another example of D1/D3 receptor interaction. Hence repeated levodopa administration induces the ectopic appearance of the D3 receptor in substance P/dynorphin, striatonigral neurons of the dorsal striatum. This induction is secondary to D1 receptor stimulation in neurons of the denervated side and fully accounts for the sensitization, i.e. the increased behavioral responsiveness to levodopa. During brain development, a similar process could operate to control the late appearance of the D3 receptor in D1-receptor bearing neurons of the ventral striatum at a time at which they start to be innervated by dopamine neurons. Finally, taking into account a variety of genetic, developmental, neuroimaging and pharmacological data, we postulate that imbalances between the levels of D1 and D3 receptors in the same neurons could be responsible for schizophrenic disorders.

A rat G protein-coupled receptor selectively expressed in myelin-forming cells

By screening an olfactory bulb cDNA library using dopamine receptor probes, we isolated the cDNA coding for the rat counterpart of an orphan receptor known as Edg-2, homologous to G protein-coupled receptors. In situ hybridization analysis showed that Edg-2 mRNA expression is restricted to myelinated structures, e.g. corpus callosum or peripheral nerves. A weaker expression in various peripheral organs was also detected in newborns. A 3.8-kb transcript was found at high levels in highly myelinated brain structures and sciatic nerve, and, at lower levels, in poorly myelinated peripheral organs, consistent with its occurrence in Schwann cells in the peripheral nervous system. One hundred percent of Edg-2 mRNA-containing cells in the brain also expressed mRNA encoding myelin-basic-protein, a marker of oligodendrocytes. This restricted olygodendrocytes localization was confirmed by the absence of cellular colocalization of Edg-2 and glial fibrillary acidic protein, an astrocytic marker. During prenatal development, Edg-2 mRNA expression was high in the cortical neuroepithelium and meningeal layer at E16, extended later to other neuroepithelia, and disappeared shortly after birth. During brain postnatal development, Edg-2 mRNA expression in myelinated structures followed a caudo-rostral gradient, similar to that of myelination. Thus, Edg-2 is the first G protein-coupled receptor found to be selectively expressed in myelin-forming cells in the nervous system and its temporal expression pattern is consistent with a dual role (i) in neurogenesis, during embryonic development, and (ii) in myelination and myelin maintenance, during postnatal life.

Introductory study of the once-a-month, injectable contraceptive Cyclofem in Brazil, Chile, Colombia, and Peru

An introductory trial with the injectable contraceptive Cyclofem was carried out in Brazil, Chile, Colombia, and Peru, with participation by 3,183 women. Women were followed-up for up to 2 years of use and the data were evaluated by life table analysis. A total of 29,676 women-months were accumulated for up to 2 years. No pregnancies were observed in the 2 years. The discontinuation rates for amenorrhea in the first year ranged from 3.4 in Brazil to 8.1 in Colombia, and for menstrual disturbances from 5.1 in Chile to 9.2 in Brazil. The discontinuation rates for other medical reasons ranged from 7.8 in Brazil to 26.3 in Colombia, and for personal reasons from 17.2 in Chile to 23.5 in Brazil. Continuation rates ranged from 42.3 in Colombia to 52 in Chile. In the second year of observation the rates of discontinuation were lower than those observed in the first year, with the exception of personal reasons in Brazil, which were the same as those observed in the first year. Continuation rates ranged from 19.4 in Brazil to 36.8 in Chile. The comparison of reasons for discontinuation in selected clinics showed that the rate for amenorrhea in one clinic in Chile was more than three times that in others and in Peru was seven times more in one clinic than in another. Regarding menstrual disturbances, in Peru one clinic presented a rate three times higher than the others. The main reasons for discontinuation due to other medical reasons were headache and weight gain. In conclusion, Cyclofem presented a high contraceptive efficacy and an acceptable rate of continuation and discontinuation for up to 2 years in the four countries.

nNOS and Ca2+ influx in rat pancreatic acinar and submandibular salivary gland cells

Regulation of agonist-activated Ca2+ influx by the NOS pathway through generation of cGMP is being found in an increasing number of cell types. In the present work, we examined the role of the NOS pathway in agonist-evoked [Ca2+]i oscillations and attempted to identify the NOS isoform most likely to regulate Ca2+ influx. For this, we first show that two Ca(2+)-mobilizing agonists acting on pancreatic acinar cells, bombesin (BS) and the cholecystokinin analog CCK-JMV-180 (CCKJ), evokes different type of [Ca2+]i oscillations. The BS-evoked [Ca2+]i oscillations rapidly became acutely dependent on the presence of extracellular Ca2+, whereas the CCKJ-evoked oscillations continue for long periods of time in the absence of Ca2+ influx. This differential behavior allowed us to isolate Ca2+ influx and study its regulation while controlling for non specific effects on all other Ca2+ transporting events involved in generating [Ca2+]i oscillations. Inhibitors of selective steps in the NOS pathway inhibited agonist-induced cGMP production. The inhibitors were then used to show that scavenging NO with reduced hemoglobin, inhibition of guanylyl cyclase with 1H-[1,2,4] oxadiazolo[4,3-a] quinoxaline-1-one (ODQ) and inhibition of protein kinase G with Rp-8-pCPT-cGMPS inhibited [Ca2+]i oscillations evoked by BS but not those evoked by CCKJ. These findings were extended to duct and acinar cells of the SMG. In these cells, Ca(2+)-mobilizing agonists stimulate large Ca2+ influx, which was inhibited by all inhibitors of the NOS pathway. Western blot analysis and immunolocalization revealed that the cells did not express iNOS, eNOS was expressed only in blood vessels and capillaries whereas nNOS was expressed at high levels next to the plasma membrane of all cells. Accordingly, the nNOS inhibitor 7-nitroindazole (7-NI) inhibited BS- but not CCKJ-evoked [Ca2+]i oscillations and Ca2+ influx into SMG acinar and duct cells. Thus, together, our findings favor nNOS as the isoform activated by the Ca2+ released from internal stores to generate cGMP and regulate Ca2+ influx.

Immuno and functional characterization of CFTR in submandibular and pancreatic acinar and duct cells

Cystic fibrosis results from defective Cl- channel activity mediated by the cystic fibrosis transmembrane conductance regulator (CFTR) gene product. In the gastrointestinal tract this is manifested in abnormal salivary secretion and pancreatic insufficiency. This is generally attributed to defective Cl- transport by the ductal system of the glands. We provide the first immunocytochemical and functional evidence for expression of CFTR protein and Cl- current in rat and mouse submandibular gland (SMG) and pancreatic acinar cells, a site proximal to the ductal system of these secretory glands. Monoclonal and polyclonal antibodies recognizing COOH-terminal epitopes of CFTR show that duct and acinar cells from the two glands express CFTR in the luminal membrane. Specificity of the polyclonal antibody was verified by absence of staining in duct and acinar cells of the SMG of cf-/cf- and delta F/delta F mice. Identification of CFTR in acinar cells was aided by demonstrating coexpression of CFTR and type 3 inositol 1,4,5-trisphosphate receptors in the luminal pole of acini and absence of type 3 inositol 1,4,5-trisphosphate receptors in ducts. Electrophysiological characterization in single SMG duct and acinar cells shows the presence of a protein kinase A-activated, voltage- and time-independent, ohmic Cl- current and absence of repolarization-dependent tail currents, all of which are kinetic properties of the CFTR-dependent Cl- channel. In addition, the channel was activated by the nonhydrolyzable ATP analog 5'-adenylylimidodiphosphate and the benzimidazalone NS-004. Channels activated by all activators were inhibited by glibenclamide and a known inhibitory antiserum [anti-CFTR-(505-511)]. Combined immunologic, functional, and pharmacological evidence allows us to conclude that acinar cells of the SMG and pancreas express functional CFTR-dependent Cl- channels. Because this site is proximal to the duct, modification of activity of this channel in acinar cells is likely to contribute to abnormal salivary secretion and pancreatic insufficiency typical of cystic fibrosis.

Polarized expression of Ca2+ pumps in pancreatic and salivary gland cells. Role in initiation and propagation of [Ca2+]i waves

The present study was aimed at localization of plasma membrane (PMCA) and intracellular (SERCA) Ca2+ pumps and characterizing their role in initiation and propagation of Ca2+ waves. Specific and polarized expression of Ca2+ pumps was observed in all epithelial cells examined. Immunolocalization revealed expression of PMCA in both the basolateral and luminal membranes of all cell types. SERCA2a appeared to be expressed in the luminal pole, whereas SERCA2b was expressed in the basal pole and the nuclear envelope of pancreatic acini. Interestingly, SERCA2b was found in the luminal pole of submandibular salivary gland acinar and duct cells. These cells expressed SERCA3 in the basal pole. To examine the significance of the polarized expression of SERCA and perhaps PMCA pumps in secretory cells, we compared the effect of inhibition of SERCA pumps with thapsigargine and partial Ca2+ release with ionomycin on Ca2+ release evoked by agonists and Ca2+ uptake induced by antagonists. Despite their polarized expression, Ca2+ uptake by SERCA pumps and Ca2+ efflux by PMCA resulted in uniform reduction in [Ca2+]i. Surprisingly, inhibition of the SERCA pumps, but not Ca2+ release by ionomycin, eliminated the distinct initiation sites and propagated Ca2+ waves, leading to a uniform increase in [Ca2+]i. In addition, inhibition of SERCA pumps reduced the rate of Ca2+ release from internal stores. The implication of these findings to rates of Ca2+ diffusion in the cytosol, compartmentalization of Ca2+ signaling complexes, and mechanism of Ca2+ wave propagation are discussed.

Polarized expression of Ca2+ channels in pancreatic and salivary gland cells. Correlation with initiation and propagation of [Ca2+]i waves

In polarized epithelial cells [Ca2+]i waves are initiated in discrete regions and propagate through the cytosol. The structural basis for these compartmentalized and coordinated events are not well understood. In the present study we used a combination of [Ca2+]i imaging at high temporal resolution, recording of Ca2+-activated Cl- current, and immunolocalization by confocal microscopy to study the correlation between initiation and propagation of [Ca2+]i waves and localization of Ca2+ release channels in pancreatic acini and submandibular acinar and duct cells. In all cells Ca2+ waves are initiated in the luminal pole and propagate through the cell periphery to the basal pole. All three cell types express the three known inositol 1,4,5-trisphosphate receptors (IP3Rs). Expression of IP3Rs was confined to the area just underneath the luminal and lateral membranes, with no detectable receptors in the basal pole or other regions of the cells. In pancreatic acini and SMG ducts IP3R3 was also found in the nuclear envelope. Expression of ryanodine receptor was detected in submandibular salivary gland cells but not pancreatic acini. Accordingly, cyclic ADP ribose was very effective in mobilizing Ca2+ from internal stores of submandibular salivary gland but not pancreatic acinar cells. Measurement of [Ca2+]i and localization of IP3Rs in the same cells suggests that only a small part of IP3Rs participate in the initiation of the Ca2+ wave, whereas most receptors in the cell periphery probably facilitate the propagation of the Ca2+ wave. The combined results together with our previous studies on this subject lead us to conclude that the internal Ca2+ pool is highly compartmentalized and that compartmentalization is achieved in part by polarized expression of Ca2+ channels.

Selective expression of dopamine D3 receptor mRNA in proliferative zones during embryonic development of the rat brain

We studied by in situ hybridization histochemistry the expression of D3 receptor (D3R) mRNA at various stages of rat brain development. The first expression of D3R mRNA was detected at embryonic day 14 (E14) in the striatal and rhinencephalic neuroepithelia and throughout the tectal neuroepithelium. From E16 to E19 D3R mRNA expression extended along a rostrocaudal axis to additional proliferative ventricular zones of the basal forebrain, including the neuroepithelia of the olfactory bulb, nucleus accumbens, septum, and amygdala, whereas D1 and D2 receptor (D1R and D2R) mRNAs were expressed predominantly by migrating neuroblasts and/or differentiating striatal neurons. Only a few neuroblasts, migrating in the lateral cortical stream or developing as cerebellar Purkinje cells, expressed D3R mRNA from E18. At birth D3R expression mRNA appeared in differentiating neuronal fields of the nucleus accumbens and medial mamillary body primordia and on P5 reached a distribution similar to that found in adult. In addition, a transient upregulation was detected on P5 in the medial mamillary bodies, parietofrontal cortex, and olfactory tubercle. In the adult brain D3R gene expression continued in the striatal proliferative subventricular zone. The late expression D3R mRNA in neurons, after achievement of dopamine innervation, supports the existence of a regulating factor released from dopamine neurons, as suggested by denervation studies in the adult. The sustained and abundant D3R gene expression, predominantly in germinative neuroepithelial zones actively involved in neurogenesis of most basal forebrain structures, supports the hypothesis of a neurogenetic but minor morphogenetic modulatory role for the D3R during CNS development.

Return of fertility after discontinuation of the once-a-month injectable contraceptive Cyclofem

The objective of this study was to evaluate the return of fertility in women who used Cyclofem as a contraceptive method during the introductory studies conducted in Brazil, Chile, Colombia, and Peru. From these four cohorts, 101 women were eligible for the study. Thirty-one were not included in the study either because they refused to be interviewed, had initiated another contraceptive method the month after discontinuation, or were unable to be contacted. A total of 70 women were included in the study. Our results showed that the return to fertility rate after the discontinuation of Cyclofem was 1.4 per 100 women at the end of the first month and reached 82.9 at one year. More than 50% were pregnant at 6 months. Fifty-one (94.4%) pregnancies ended in a live birth, two were spontaneous first trimester abortions, and one was a hydatidiform mole. Return of fertility was not related to the woman's age at the time of discontinuation, her weight, or the number of Cyclofem injections. In conclusion, fertility is restored by 1 month following Cyclofem discontinuation. Users and potential users should be counseled regarding the rapid return of fertility after discontinuing this method of contraception.

One-on-one mentor-resident rotation for improving continuity of care in a surgical training program

The modern resident team, staffed by multiple attendings, often makes sacrifices on continuity of care due to scheduling conflicts. We investigated a one-on-one mentor-resident rotation where all clinical activities were synchronized to produce near-perfect continuity of care, and we compared the objective and subjective outcome measures to those of control rotations of the same resident during the same year. The results showed that continuity of care close to 100% was possible in such rotations, but work hours were increased by 25%. Also, the number of patients seen was decreased by over 50%. The rotation was well-received by both mentors and residents. Continuity of care per se can be improved by this rotation. However, theoretical disadvantages, mainly narrow training due to exposure to only one mentor and fewer patients, make it unsuitable for extended use.

A case-controlled study of laparoscopic splenectomy

BACKGROUND

The utility of laparoscopic splenectomy (LS) has not been tested in general surgical practice. This is a case controlled study comparing the clinical results and economics of L.S. and open splenectomy (OS) in a community hospital.

METHODS

The outcome of a series of 15 patients undergoing LS were compared to 15 patients undergoing OS matched for diagnosis, splenic weight, age, and main co-morbidites, selected by a person independent of the project.

RESULTS

In both series, the indications were immune thrombocytopenic purpura, hemolytic anemias, hairy cell leukemia and, staging for Hodgkin's disease. LS resulted in shorter hospitalization (2.3 vs 8.8 days) with fewer postoperative complications. However, the operation was 1.7 times as long, and the operating room charge 2.9 times as high, so that the total cost of LS ($18,015) was greater than that for OS ($14,524). If the cost of treatment of complications is included, then the total is the same for both at our institutions.

CONCLUSION

Except for a few indications not addressed in this study, LS can be used in lieu of OS.

Induction of dopamine D3 receptor expression as a mechanism of behavioral sensitization to levodopa

In rats with unilateral lesions of the nigrostriatal dopamine pathway with 6-hydroxydopamine, the motor stimulating effects of levodopa, an indirect dopamine receptor agonist, evidenced by contraversive rotations, become enhanced upon repeated intermittent administration. However, the mechanisms of this behavioral sensitization are essentially unknown. We show that development of sensitization is accompanied by a progressive appearance of D3 receptor mRNA and binding sites, visualized by in situ hybridization and 7-[3H] hydroxy-N,N-di-n-propyl-2-aminotetralin autoradiography, respectively, occurring in the denervated caudate putamen, a brain area from which this receptor subtype is normally absent. Development and decay of these two processes occur with closely parallel time courses, whereas there were no marked changes in D1 or D2 receptor mRNAs. D3 receptor induction by levodopa is mediated by repeated D1 receptor stimulation, since it is prevented by the antagonist SCH 33390 and mimicked by the agonist SKF 38393, but not by two D2 receptor agonists. The enhanced behavioral response to levodopa is mediated by the newly synthesized D3 receptor, since it is antagonized by nafadotride, a preferential D3 receptor antagonist, in low dosage, which has no such effect before D3 receptor induction. D3 receptor induction and behavioral sensitization are also accompanied by a sustained enhancement of prodynorphin mRNA level and a progressively decreasing expression of the preprotachykinin gene. We propose that imbalance between dynorphin and substance P release from the same striatonigral motor efferent pathway, related to D3 receptor induction, is responsible for behavioral sensitization.

The effects of IFN-gamma activated mouse peritoneal and alveolar macrophages on Cryptosporidium parvum development

Mouse peritoneal and alveolar macrophages were interacted in vitro with C. parvum oocysts and cultured in normal medium and in medium with IFN-gamma. The results showed that in vitro activation of macrophages by IFN-gamma limits C. parvum development although the inhibitory effect is not as potent as in other intracellular parasitic protozoa.

Urea inhibits Na-K-2Cl cotransport in medullary thick ascending limb cells

We examined the effect of physiological concentrations of urea (100-500 mM) on Na-K-2Cl cotransport in cultured cells from mouse medullary thick ascending limb (mTAL). Urea acutely inhibited bumetanide-sensitive K influx in mTAL cells in a concentration-dependent fashion, with a statistically significant inhibition (19%) at 100 mM and 86% inhibition at 500 mM. The effect of urea was entirely reversible and was blocked by prior treatment with okadaic acid, a phosphatase inhibitor, suggesting that urea exerts its action upstream of the phosphorylation-dephosphorylation step. Cell volume was unchanged in the presence of 500 mM urea. The number of [3H]bumetanide binding sites, a measure of the number of functioning cotransporter sites, was decreased in the presence of urea, and the decrease in bumetanide binding was proportional to the decrease in bumetanide-sensitive K influx. Urea also stimulated the Ba-sensitive swelling-activated K efflux from mTAL cells. Thus urea, in concentrations that prevail in the renal medulla, alters ion transport in mTAL cells.

Effect of Anapsos (Polypodium leucotomos extract) on in vitro production of cytokines

AIMS

The aim of the study was to test the immunomodulating capacity of Anapsos, Polypodium leucotomos extract, in vitro in an attempt to explore how this extract acts from an immunological point of view and thus to identify a common link capable of explaining most of its effects.

METHODS

Polypodium leucotomos rhizomes were harvested in Guatemala and the extract, Anapsos, obtained. Mononuclear cells were obtained by density gradient centrifugation from healthy donors, and stimulated with phytohemagglutinin or Pokeweed with and without Anapsos and with Anapsos alone. Cell proliferation was determined by thymidine incorporation. Cells were also stimulated and the following cytokines determined by ELISA at 0, 12, 24, 48, 72, and 96 h: IL-1 beta, TNF-alpha, IL-2, INF-8, IL-4 and IL-10.

RESULTS

Anapsos, Polypodium leucotomos extract, has a modulating effect on the in vitro production and release of cytokines by peripheral blood mononuclear cells of healthy subjects. At doses effective in vivo, Anapsos can stimulate PBMNc proliferation, delay IL-1 beta secretion and at the same time increase that of IL-2, IL-10, and INF-gamma.

CONCLUSIONS

Anapsos may have an antagonistic effect on some of the cytokines released on cell stimulation with LPS and/or PHA, which suggests that this product has a pleiotropic effect on different populations in the immune system.

The use of vaginal ultrasound to identify copper T IUDs at high risk of expulsion

A total of 235 women who had a TCu 380A IUD inserted had a vaginal ultrasound scan performed to identify if the IUDs were correctly placed in the uterine fundus. Women identified as having a misplaced IUD had it removed. The remaining women were compared to 201 women who had an IUD inserted and had no ultrasound evaluation, matched by age and parity. Women were followed-up for one year. Gross cumulative discontinuation rates and continuation rates were calculated by life table analysis. Comparison between groups was done by the Gehan test. The study group had 34 IUDs removed because they were misplaced according to the established criteria. The expulsion rate was significantly higher in the control group, also influencing the continuation rate which was lower in the same group. Of the 34 women who had their IUD removed because it was not correctly placed, only 22 requested and had another IUD inserted. The removal of IUD determined by an ultrasound to be incorrectly placed significantly decreased expulsion rates. However, many IUDs may have been removed unnecessarily, probably resulting in many women not returning to the clinic or deciding to use another contraceptive method.