Diserinol Isophthalamide: A Novel Reagent for Complexation with Biomolecular Anions in Electrospray Ionization Mass Spectrometry

Transferring biomolecules from solution to vacuum facilitates a detailed analysis of molecular structure and dynamics by isolating molecules of interest from a complex environment. However, inherent in the ion desolvation process is the loss of solvent hydrogen bonding partners, which are critical for the stability of a condensed-phase structure. Thus, transfer of ions to vacuum can favor structural rearrangement, especially near solvent-accessible charge sites, which tend to adopt intramolecular hydrogen bonding motifs in the absence of solvent. Complexation of monoalkylammonium moieties (e.g., lysine side chains) with crown ethers such as 18-crown-6 can disfavor structural rearrangement of protonated sites, but no equivalent ligand has been investigated for deprotonated groups. Herein we describe diserinol isophthalamide (DIP), a novel reagent for the gas-phase complexation of anionic moieties within biomolecules. Complexation is observed to the C-terminus or side chains of the small model peptides GD, GE, GG, DF-OMe, VYV, YGGFL, and EYMPME in electrospray ionization mass spectrometry (ESI-MS) studies. In addition, complexation is observed with the phosphate and carboxylate moieities of phosphoserine and phosphotyrosine. DIP performs favorably in comparison to an existing anion recognition reagent, 1,1'-(1,2-phenylene)bis(3-phenylurea), that exhibits moderate carboxylate binding in organic solvent. This improved performance in ESI-MS experiments is attributed to reduced steric constraints to complexation with carboxylate groups of larger molecules. Overall, diserinol isophthalamide is an effective complexation reagent that can be applied in future work to study retention of solution-phase structure, investigate intrinsic molecular properties, and examine solvation effects.

Obesity induces gut microbiota alterations and augments acute graft-versus-host disease after allogeneic stem cell transplantation

The efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) is limited by acute and chronic graft-versus-host disease (GVHD). The impact of obesity on allo-HSCT outcomes is poorly understood. Here, we report that obesity had a negative and selective impact on acute gut GVHD after allo-HSCT in mice with diet-induced obesity (DIO). These animals exhibited increased gut permeability, endotoxin translocation across the gut, and radiation-induced gastrointestinal damage after allo-HSCT. After allo-HSCT, both male and female DIO mouse recipients showed increased proinflammatory cytokine production and expression of the GVHD marker ST2 (IL-33R) and MHC class II molecules; they also exhibited decreased survival associated with acute severe gut GVHD. This rapid-onset, obesity-associated gut GVHD depended on donor CD4⁺ T cells and occurred even with a minor MHC mismatch between donor and recipient animals. Retrospective analysis of clinical cohorts receiving allo-HSCT transplants from unrelated donors revealed that recipients with a high body mass index (BMI, >30) had reduced survival and higher serum ST2 concentrations compared with nonobese transplant recipients. Assessment of both DIO mice and allo-HSCT recipients with a high BMI revealed reduced gut microbiota diversity and decreased Clostridiaceae abundance. Prophylactic antibiotic treatment protected DIO mouse recipients from endotoxin translocation across the gut and increased inflammatory cytokine production, as well as gut pathology and mortality, but did not protect against later development of chronic skin GVHD. These results suggest that obesity-induced alterations of the gut microbiota may affect GVHD after allo-HSCT in DIO mice, which could be ameliorated by prophylactic antibiotic treatment.

Thymic Epithelial Cell Support of Thymopoiesis Does Not Require Klotho

Age-related thymic involution is characterized by a decrease in thymic epithelial cell (TEC) number and function parallel to a disruption in their spatial organization, resulting in defective thymocyte development and proliferation as well as peripheral T cell dysfunction. Deficiency of Klotho, an antiaging gene and modifier of fibroblast growth factor signaling, causes premature aging. To investigate the role of Klotho in accelerated age-dependent thymic involution, we conducted a comprehensive analysis of thymopoiesis and peripheral T cell homeostasis using Klotho-deficient (Kl/Kl) mice. At 8 wk of age, Kl/Kl mice displayed a severe reduction in the number of thymocytes (10-100-fold reduction), especially CD4 and CD8 double-positive cells, and a reduction of both cortical and medullary TECs. To address a cell-autonomous role for Klotho in TEC biology, we implanted neonatal thymi from Klotho-deficient and -sufficient mice into athymic hosts. Kl/Kl thymus grafts supported thymopoiesis equivalently to Klotho-sufficient thymus transplants, indicating that Klotho is not intrinsically essential for TEC support of thymopoiesis. Moreover, lethally irradiated hosts given Kl/Kl or wild-type bone marrow had normal thymocyte development and comparably reconstituted T cells, indicating that Klotho is not inherently essential for peripheral T cell reconstitution. Because Kl/Kl mice have higher levels of serum phosphorus, calcium, and vitamin D, we evaluated thymus function in Kl/Kl mice fed with a vitamin D-deprived diet. We observed that a vitamin D-deprived diet abrogated thymic involution and T cell lymphopenia in 8-wk-old Kl/Kl mice. Taken together, our data suggest that Klotho deficiency causes thymic involution via systemic effects that include high active vitamin D levels.

T cell progenitor therapy-facilitated thymopoiesis depends upon thymic input and continued thymic microenvironment interaction

Infusion of in vitro-derived T cell progenitor (proT) therapy with hematopoietic stem cell transplant aids the recovery of the thymus damaged by total body irradiation. To understand the interaction between proTs and the thymic microenvironment, WT mice were lethally irradiated and given T cell-deficient (Rag1-/-) marrow with WT in vitro-generated proTs, limiting mature T cell development to infused proTs. ProTs within the host thymus led to a significant increase in thymic epithelial cells (TECs) by day 21 after transplant, increasing actively cycling TECs. Upon thymus egress (day 28), proT TEC effects were lost, suggesting that continued signaling from proTs is required to sustain TEC cycling and cellularity. Thymocytes increased significantly by day 21, followed by a significant improvement in mature T cell numbers in the periphery by day 35. This protective surge was temporary, receding by day 60. Double-negative 2 (DN2) proTs selectively increased thymocyte number, while DN3 proTs preferentially increased TECs and T cells in the spleen that persisted at day 60. These findings highlight the importance of the interaction between proTs and TECs in the proliferation and survival of TECs and that the maturation stage of proTs has unique effects on thymopoiesis and peripheral T cell recovery.

The increase in thymopoiesis following T cell progenitor therapy is dependent upon the input population and continued interaction between developing T cells and the thymic microenvironment

The inclusion of in vitro derived T cell progenitor (proT) therapy with hematopoietic stem cell transplant (HSCT) aids in the recovery of the thymus damaged by total body irradiation and improves de novo thymopoiesis. To understand the interaction between proTs and the thymic microenvironment, wildtype (WT) mice were lethally irradiated and given T cell deficient donor (Rag1−/−) marrow along with in vitro generated proT from WT donors, limiting mature T cell development to infused proT. Donor proTs within the host thymus led to a significant increase in thymic epithelial cell (TEC) numbers by day 21 post-transplant, and increased actively cycling TECs as measured by Ki67 expression and BrdU uptake. However, that gain was temporary and lost by day 28, suggesting that continued signaling from proT cells is required to sustain TEC cycling and mass. We also find a significant improvement in total thymocyte number by day 21 followed by a significant increase in the total mature T cell number in the secondary lymphoid organs by day 28. This protective surge is also temporary, receding by day 60. In this time period, infused DN2 proTs selectively increased thymocyte number while DN3 proTs preferentially led to a greater TEC numbers. Interestingly, an exception in persistence occurs when DN3 proTs are used and the increase in mature T cells in the spleen persists at day 60. As a result of the lack of competition for thymic niches by cells from the Rag1−/− graft, a subpopulation of the infused proT persisted in the thymus in an immature state at day 60. These findings highlight the importance of the interaction between developing T cells and TECs in the proliferation and survival of these critical components of the thymic microenvironment.

OT2-05-05: Phase I/II Study of Adoptive T Cell Therapy Following In Vivo Priming with a HER2 Peptide-Based Vaccine in Patients with Stage IV Breast Cancer

Background

Adoptive T cell therapy has evolved from preclinical setting to a potentially feasible treatment strategy for advanced breast cancer (BC). However, the ability to expand tumor antigen specific T cells ex vivo has been one of the major hurdles that has limited clinical translation of adoptive T cell therapy. Tumor specific T cells are rare in unprimed patients and generating large bulk cultures from rare precursor frequencies is difficult. We have found immunizing HER2+ patients to increase tumor specific T cell precursor frequencies to the levels of a vaccinated foreign antigen markedly improves the ability to generate large numbers of tumor specific T cells in vitro. We hypothesize that T cell expansion strategies that are facilitated by prior immunization will be clinically useful in the treatment of advanced BC.

Design: A Phase I/II non-randomized, single arm study. Priming with a HER2 ICD vaccine will be performed at 1 week intervals for a total of 3 vaccines. Patients will undergo leukapheresis 2 weeks after the 3rd vaccine to collect PBMC for T cell expansion. Patients will be pre-treated with cyclophosphamide 24 hours prior to 1st T cell infusion and then receive up to 3 dose-escalating infusions of T cells given 7–10 days apart. Three HER2 vaccine booster immunizations will then be administered at 1, 2, and 4 months after the final T cell infusion. Follow-up for persistent and continued immunity will then ensue.

Aims: To evaluate the safety of infusing escalating doses of HER2 specific T cells into patients with advanced HER2+ BC using ex vivo expanded autologous T cells, to investigate to what extent HER2 specific T cell immunity can be boosted or generated in individuals after infusion of HER2 specific T cells, to evaluate how long T cell immune augmentation persists in vivo after adoptive transfer of HER2 specific T cells and subsequent booster immunizations.

Criteria: Patients with HER2+ Stage IV BC who: have been maximally treated and not achieved a complete remission, have stable or slowly progressive disease, HER2+, and have adequate LVEF.

Statistical Methods: Toxicity will be determined by chemical and clinical parameters evaluated at various time points. If the true probability of a DLT is 0.11, then the probability of observing 0 DLT's in 20 patients is 0.097. If the true probability of a DLT is 0.18, then the probability of observing ≤1 DLT's in 20 patients is 0.102, and if the true probability of a DLT is 0.27, then the probability of observing ≤2 DLT's in 20 patients is 0.064. Therefore, with low observed rates of DLT (≤10%), we can be reasonably confident (∼90%) with 20 patients that the true DLT rate is < 0.27. Immunologic response, defined as the successful boosting of precursor frequency with infusion of HER2−specific T cells, will be evaluated by assessing the change in T cell level from baseline. To assess the durability of the T cell response, we are primarily interested in estimating the proportion of patients whose T cells persist at a level the same or greater as the level after the final T cell infusion as long as 6 months following the final booster vaccine.

Accrual: Target=20/Actual=14

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr OT2-05-05.

Post-operative infection after minimally invasive versus open transforaminal lumbar interbody fusion (TLIF): literature review and cost analysis

INTRODUCTION

Surgical site infection (SSI) in the setting of lumbar fusion is associated with significant morbidity and medical resource utilization. To date, there have been no studies conducted with sufficient power to directly compare the incidence of SSI following minimally invasive (MIS) vs. open TLIF procedures. Furthermore, studies are lacking that quantify the direct medical cost of SSI following fusion procedures. We set out to determine the incidence of SSI in patients undergoing MIS vs. open TLIF reported in the literature and to determine the direct hospital cost associated with the treatment of SSI following TLIF at our institution.

METHODS

A systematic Medline search was performed to identify all published studies assessing SSI after MIS or open TLIF. The cumulative incidence of SSI was calculated from all reported cohorts and compared between MIS vs. open TLIF. In order to determine the direct hospital costs associated with the treatment of SSI following TLIF, we retrospectively reviewed 120 consecutive TLIFs performed at our institution, assessed the incidence of SSI, and calculated the SSI-related hospital costs from accounting and billing records.

RESULTS

To date, there have been 10 MIS-TLIF cohorts (362 patients) and 20 open-TLIF cohorts (1 133 patients) reporting incidences of SSI. The cumulative incidence of reported SSI was significantly lower for MIS vs. open-TLIF (0.6% vs. 4.0%, p=0.0005). In our experience with 120 open TLIF procedures, SSI occurred in 6 (5.0%) patients. The mean hospital cost associated with the treatment of SSI following TLIF was $ 29,110 in these 6 cases. The 3.4% decrease in reported incidence of SSI for MIS vs. open-TLIF corresponds to a direct cost savings of $ 98,974 per 100 MIS-TLIF procedures performed.

CONCLUSIONS

Post-operative wound infections following TLIF are costly complications. MIS vs. open TLIF is associated with a decreased reported incidence of SSI in the literature and may be a valuable tool in reducing hospital costs associated with spine care.

Dimers of the neuropeptide Y (NPY) Y2 receptor show asymmetry in agonist affinity and association with G proteins

In conditions precluding activation of G proteins, the binding of agonists to dimers of the neuropeptide Y (NPY) Y2 receptor shows two components of similar size, but differing in affinity. The dimers of all NPY receptors are solubilized as approximately 180-kDa complexes containing one G protein alpha beta gamma trimer. These heteropentamers are stable to excess agonists, chelators, and alkylators. However, dispersion in the weak surfactant cholate releases approximately 300-kDa complexes. These findings indicate that both protomers in the Y2 dimer are associated with G protein heterotrimers, but the extent of interaction depends on affinity for the agonist peptide. The G protein in contact with the first-liganded, higher-affinity protomer should have a stronger interaction with the receptor and a larger probability of activation.

Oligomerization of the heptahelical G protein coupling receptors: a case for association using transmembrane helices

The heptahelical G protein coupling receptors oligomerize extensively via transmembrane domains, in association with heterotrimeric G proteins. This provides higher affinity for agonists, conformational stability necessary for signal transduction, and protection from intracellular proteinases. The oligomerization is relevant to organismic pathophysiology and could be targeted by natural or modified agonists.

The neuropeptide Y (NPY) Y2 receptors are largely dimeric in the kidney, but monomeric in the forebrain

The neuropeptide Y(NPY) Y2 receptors are detected largely as dimers in the clonal expressions in CHO cells and in particulates from rabbit kidney cortex. However, in two areas of the forebrain (rat or rabbit piriform cortex and hypothalamus), these receptors are found mainly as monomers. Evidence is presented that this difference relates to large levels of G proteins containing the Gi alpha -subunit in the forebrain areas. The predominant monomeric status of these Y2 receptors should also be physiologically linked to large synaptic inputs of the agonist NPY. The rabbit kidney and the human CHO cell-expressed Y2 dimers are converted by agonists to monomers in vitro at a similar rate in the presence of divalent cations.

Neuropeptide Y Y2 receptor in health and disease

We briefly survey the current knowledge and concepts regarding structure and function of the neuropeptide Y Y2 receptor and its agonists, especially as related to pharmacology of the receptor and its roles in pathological processes. Specific structural features are considered that could be responsible for the known compartmentalization and participation of the receptor in cell and tissue organization. This is further discussed in relation to changes of levels of the Y2 receptor in pathological conditions (especially in epilepsy and drug abuse), to endocytosis and recycling, and to participation in wound healing, retinopathy and angiogenesis. Properties of the receptor and of Y2 agonists are considered and reviewed in connection to the negative regulation of transmitter release, feeding, mood and social behavior. The possible involvement of the Y2 receptor in diabetes, carcinogenesis and bone formation is also reviewed.

Oligomerization of neuropeptide Y (NPY) Y2 receptors in CHO cells depends on functional pertussis toxin-sensitive G-proteins

Human neuropeptide Y Y2 receptors expressed in CHO cells are largely oligomeric, and upon solubilization are recovered by density gradient centrifugation as approximately 180 kDa complexes of receptor dimers and G-protein heterotrimers. A large fraction of the receptors is inactivated in the presence of pertussis toxin, in parallel with inactivation of Gi alpha subunits (with half-periods of about 4 h for both). This is accompanied by a very long-lasting loss of receptor dimers and of masked surface Y2 sites (an apparent receptor reserve pre-coupled mainly to Gi alpha subunit-containing G-proteins). However, surface Y2 receptors accessible to large peptide agonists are much less sensitive to the toxin. All surface Y2 receptors are rapidly blocked by Y2 antagonist BIIE0246, with a significant loss of the dimers, but with little change of basal Gi activity. However, both dimers and Y2 receptor compartmentalization are restored within 24 h after removal of the antagonist. In CHO cells, the maintenance and organization of Y2 receptors appear to critically depend on functional pertussis toxin-sensitive G-proteins.

Self-regulation of agonist activity at the Y receptors

Neuropeptide Y (NPY) is one of the most abundant neuropeptides, and is likely to be present at nanomolar levels over extended periods in the synaptic space of many forebrain areas. This might be linked to an evolved generalized toning activity through a number of other peptide receptors that use C-terminally amidated agonists (with LHRH and orexin receptors and GIR as examples). However, the Y1 and Y2 receptors (which constitute the bulk of Y receptors active in the neural matrix) possess subnanomolar affinities that, at saturating NPY levels, could produce excessive signaling, as well as receptor losses via repeated endocytosis. The related Y4 receptor shows an even higher agonist affinity, and faces the same problem in visceral and neural locations accessible to pancreatic polypeptide (PP). An examination of agonist peptide interaction with Y receptors shows that Y1 and Y4 receptors in particular (as located on either the intact cells, or on particulates derived from various cell types) develop a blockade dependent on ligand concentration, with the blocking ranks of [NPY]>>[peptide YY] (PYY) for the Y1, and [human PP]>>>[PYY-related Y4 agonist] for the Y4 receptor. This blockade is also echoed in a concentration-related reduction in biological activity of primary agonists (NPY and PP), resembling a partial agonism, and is influenced especially by the allosteric interactivity of agonists. With the Y2 receptor, the blocking by agonists is less pronounced, but the signaling by NPY-related peptides is apparently less than with PYY-related agonists. The extended occupancy and self-attenuation of primary agonist activity at Y receptors could represent an evolutionary solution contributing to a balancing of metabolic signaling, agonist clearance and receptor conservation.

Internalization of cloned pancreatic polypeptide receptors is accelerated by all types of Y4 agonists

Internalization of cloned rat or human Y4 receptors expressed in Chinese hamster ovary (CHO) cells increased with concentration of all types of Y4 agonists, including human and rat pancreatic polypeptides, the Y1 receptor group co-agonists possessing C-terminal TRPRY.NH2 pentapeptide, and a C-terminally amidated dimeric nonapeptide related to neuropeptide Y, GR231118. These peptides also inhibited forskolin-stimulated adenylyl cyclase activity in Y4 receptor-expressing cells, and stimulated the binding of 35S-labeled GTP-gamma-S to pertussis toxin-sensitive G-proteins in particulates from these cells. Peptide VD-11 (differing from GR231118 only by C-terminal oxymethylation) acted as a competitive antagonist in all of the above processes. Agonist-induced stimulation of the Y4 receptor internalization persisted in the presence of allosteric inhibitors of hPP binding, N5-substituted amilorides, which also were relatively little active in G-protein stimulation and cyclase inhibition by Y4 agonists. Acceleration of Y4 receptor internalization by agonists apparently is related to relaxation of allosteric constraints to ligand attachment and sequestration of the receptor-ligand complex.

Agonist internalization by cloned Y1 neuropeptide Y (NPY) receptor in Chinese hamster ovary cells shows strong preference for NPY, endosome-linked entry and fast receptor recycling

In Chinese hamster ovary (CHO) cells expressing the cloned guinea-pig Y1 receptor, the saturable, receptor-linked internalization of NPY (NPY)-related peptides showed the rank order of human/rat neuropeptide Y (hNPY)>pig/rat peptide YY (pPYY)>=(Pro(34))human PYY>(Leu(31),Pro(34))hNPY>(Leu(31),Pro(34))hPYY>>BVD-11 (a selective Y1 antagonist). All agonists accessed similar numbers of Y1 sites in particulates from disrupted cells, with relatively small affinity variation. The rate of internalization could significantly depend on the overall interactivity of the agonist peptide (reflected in sensitivity to chaotropic agents, as well as in the level of non-saturable binding and internalization). Concentration-dependent inhibition of the agonist-driven CHO-Y1 internalization was found with filipin III (a cholesterol-complexing macrolide), and confirmed with inhibitors of clathrin lattice formation, phenylarsine oxide (PAO) and sucrose. In the concentration range affecting Y1 internalization, none of the above treatments or agents significantly alter agonist affinity for Y1 cell surface or particulate receptors. Largely similar responses to the above inhibitors were observed in CHO-Y1 cells for internalization of human transferrin. Internalization of CHO-Y1 receptor apparently is driven by NPY in strong preference to other naturally encountered agonists. At 37 degrees C, most of the internalized receptor is rapidly recycled through endosome-like membrane elements, detectable in Percoll gradients.

Blockade of pancreatic polypeptide-sensitive neuropeptide Y (NPY) receptors by agonist peptides is prevented by modulators of sodium transport. Implications for receptor signaling and regulation

Ligand binding to rodent pancreatic polypeptide-responding neuropeptide Y (NPY) receptors (here termed PP/NPY receptors), or to cloned Y4 or Y5 receptors, is selectively inhibited by amiloride, peptide or alkylating modulators of sodium transport. The PP/NPY and Y4 receptors are also selectively blocked by human or rat pancreatic polypeptide (PP) and the blocking peptides are not dissociated by high concentrations of alkali chlorides (which restore most of the binding of subtype-selective agonists to Y1 and Y2 sites). The PP/NPY receptors could also be blocked by NPY and related full-length peptides, including Y1-selective agonists (IC50 300-400 pM). The cloned Y(4) receptors from three species are much less sensitive to NPY or PYY. The sensitivity of both the PP/NPY sites and the Y(4) sites to Y2-selective peptides is quite low. The ligand attachment to PP/NPY sites is also very sensitive to peptidic Y1 antagonist ((Cys31,NVal34NPY27-36))2, which however blocks these sites at much higher molarities. Blockade of PP/NPY and Y4 sites by agonist peptides can be largely prevented by N5-substituted amiloride modulators of Na+ transport, and by RFamide NRNFLRF.NH2, but not by Ca2+ channel blockers, or by inhibitors of K+ transport. Protection of both PP/NPY and Y4 sites against blockade by human or rat pancreatic polypeptide is also afforded by short N-terminally truncated NPY-related peptides. The above results are consistent with a stringent and selective activity regulation for rabbit PP/NPY receptor(s) that may serve to differentiate agonists and constrain signaling, and could involve transporter-like interactants.

Cloned neuropeptide Y (NPY) Y1 and pancreatic polypeptide Y4 receptors expressed in Chinese hamster ovary cells show considerable agonist-driven internalization, in contrast to the NPY Y2 receptor

Guinea-pig neuropeptide Y1 and rat pancreatic polypeptide Y4 receptors expressed in Chinese hamster ovary cells were internalized rapidly upon attachment of selective peptide agonists. The Y1 and Y2, but not the Y4, receptor also internalized the nonselective neuropeptide Y receptor agonist, human/rat neuropeptide Y. The internalization of guinea-pig neuropeptide Y2 receptor expressed in Chinese hamster ovary cells was small at 37 degrees C, and essentially absent at or below 15 degrees C, possibly in connection to the large molecular size of the receptor-ligand complexes (up to 400 kDa for the internalized fraction). The rate of intake was strongly temperature dependent, with essentially no internalization at 6 degrees C for any receptor. Internalized receptors were largely associated with light, endosome-like particulates. Sucrose dose-dependently decreased the internalization rate for all receptors, while affecting ligand attachment to cell membrane sites much less. Internalization of the Y1 and the Y4 receptors could be blocked, and that of the Y2 receptor significantly inhibited, by phenylarsine oxide, which also unmasked spare cell-surface receptors especially abundant for the Y2 subtype. The restoration of Y1 and Y4 receptors after agonist peptide pretreatment was decreased significantly by cycloheximide and monensin. Thus, in Chinese hamster ovary cells the Y1 and Y4 receptors have much larger subcellular dynamics than the Y2 receptor. This differential could also hold in organismic systems, and is comparable with the known differences in internalization of angiotensin, bradykinin, somatostatin and opioid receptor subtypes.

Hypothalamic orexin-A binding sites are downregulated by chronic nicotine treatment in the rat

Chronic nicotine treatment (4 mg/kg per day; 14 days) significantly reduced the affinity and density of orexin-A binding sites in the anterior hypothalamus of rat brain. There was a significantly lower sensitivity of orexin-A binding to orexin peptides, to the related secretin and pituitary adenylate cyclase activating peptide, and to unrelated neuropeptide Y (NPY). This change correlated with selective downregulation of a fraction of hypothalamic NPY Y(1) receptors. In previous studies, we have demonstrated an increase in the levels of orexin-A peptide and NPY in discrete hypothalamic areas upon nicotine treatment. This finding contradicts an expected increase in the production of these orexigenic peptides in a model where an inverse relationship is observed between food consumption and nicotine treatment. This study provides a possible explanation to this inconsistency in that a decrease in affinity of orexin-A binding could reduce neural orexin signaling, which may contribute to decreased food intake observed in smokers and animals chronically treated with nicotine.

Nicotine up-regulates expression of orexin and its receptors in rat brain

Orexins are two recently discovered neuropeptides that can stimulate food intake. As the chronic use of tobacco typically leads to a reduction in body weight, it is of interest to determine whether nicotine, the major biologically active tobacco ingredient, has an effect on orexin metabolism in the brain. Using a semiquantitative RT-PCR technique, the levels of messenger RNA (mRNA) for prepro-orexin, orexin A (OX1-R) and orexin B (OX2-R) receptors were 20-50% higher in rats receiving nicotine for 14 days at the level of 2-4 mg/kg day compared with rats receiving saline solvent alone. In animals treated with nicotine at 4 mg/kg x day, the expression levels of mRNA for prepro-orexin, OX1-R, and OX2-R were significantly higher compared with those in either the free-feeding control or pair-fed saline control rats. RIA data indicated that both orexin A and orexin B peptide levels were significantly elevated (45-54%; P < 0.01) in the dorsomedial nucleus (DMH) of the nicotine-treated rats compared with either solvent-only or pair-fed controls. Additionally, orexin B was significantly elevated (83%; P < 0.01), over levels in both types of the control animals, in the paraventricular nucleus (PVN) region. In summary, we demonstrated that an inverse association between nicotine and food intake as well as body weight held with doses comparable to those consumed by average human smokers. Moreover, our data indicated that chronic exposure to nicotine can induce a long-term increase in the expression levels of prepro-orexin and their receptor mRNA in the rat hypothalamus and in the levels of orexin A in the DMH and orexin B in the DMH and PVN among the six hypothalamic regions that we examined.

Regulation of feeding-associated peptides and receptors by nicotine

Although numerous epidemiological studies have provided convincing evidence for the inverse association between tobacco smoking and body weight, the molecular mechanisms underlying this relationship are not well-understood. Nicotine, as a potent secretagogue, could be expected to influence the levels and expression of many classes of neurotransmitters, as well as of cell-membrane constituents linked to neurotransmission, including signal transducers and related effectors. A potentially major group of candidate molecules that could be involved in feeding-related actions of nicotine are the numerous neuropeptides and peptide hormones shown in the past two decades to regulate food intake and energy expenditure. These could include neuropeptide Y (NPY), orexins, leptins, and uncoupling proteins (UCPs). Some of these peptides were already shown to respond to nicotine treatment in terms of regulation of levels and of activity at the level of cell-membrane receptors. The primary objective of this review is to summarize our current understanding of the regulatory effects of nicotine on the food intake and energy expenditure as related to the expression levels of leptin, NPY, orexin, uncoupling proteins, and of NPY and orexin receptors.

Sensitivity of orexin-A binding to phospholipase C inhibitors, neuropeptide Y, and secretin

The binding of [(125)I] orexin-A (Ox-A) to particulates from Chinese hamster ovary (CHO) cells expressing the cloned orexin-A receptor, or from rat forebrain areas, was sensitive to blockers of phosphatidylinositol-specific phospholipase C (PtdIns-PLC) U-73122 and ET-18-OCH(3), little affected by phospholipase A(2) inhibitor quinacrine, and not sensitive to D609, a xanthate inhibitor of phosphatidylcholine-selective PLC. Interaction of the receptor with a PtdIns-PLC was further indicated by a large sensitivity of the binding to Ca(2+). Up to 50% of the binding was sensitive to the G-protein nucleotide site agonist GTP-gamma-S. Ligand attachment to the orexin-A receptor thus depends on an association with both PtdIns-PLC and G-protein alpha-subunits. In all paradigms examined, the binding of [(125)I]orexin-A was competed by human/rat neuropeptide Y (hNPY) and porcine secretin with a potency similar to orexin-A (IC(50) range 30-100 nM). The rank order of potency for NPY-related peptides was hNPY > porcine peptide YY (pPYY) > (Leu(31), Pro(34)) human PYY > human PYY(3-36) > hNPY free acid > human pancreatic polypeptide. Among secretin-related peptides, the rank order of potency was porcine secretin > or = orexin-A > human pituitary adenylate cyclase-activating peptide > orexin-B > porcine vasoactive intestinal peptide. Among opioid peptides, rat beta-endorphin and camel delta-endorphin were much less active than NPY and secretin, and two enkephalins were inactive at 1 microM. In view of high abundance of NPY in forebrain, the above cross-reactivity could indicate a significant contribution of NPY to signaling via orexin-A receptors.

Nicotine administration enhances NPY expression in the rat hypothalamus

Epidemiological studies have shown an inverse relationship between cigarette smoking and body weight. In rodents, a negative correlation between nicotine and body weight has been reported, but this observation was largely derived from studies where relatively high doses of nicotine ( approximately 12 mg/kg/day) were used. In the current study, we showed that a negative relationship also holds for low doses of nicotine that are comparable to that consumed by average human smokers (<6 mg/kg/day). We also demonstrated that 14 days of nicotine administration (4 mg/kg/day) reduced average daily food intake by 19.5% (P<0.01) in the free-feeding nicotine-treated group compared to saline controls. No significant differences in body weight were detected between the nicotine-treated and pair-fed groups. To determine whether the effects of nicotine on food intake and body weight were related to neuropeptide Y (NPY) expression, semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and radioimmunoassay were utilized to measure NPY mRNA and peptide levels in various regions of the hypothalamus. Significantly higher levels of NPY mRNA (ca. 20-50%) and peptide (ca. 24-69%) were only detected in the nicotine-treated groups. In addition, significantly higher NPY contents were also obtained in two hypothalamic areas of pair-fed control animals. In summary, our data suggest that the pharmacological effects of nicotine on food intake and body weight may be mediated by changes in hypothalamic NPY levels, a neuropeptide that is pivotal to the hypothalamic regulation of food intake.

Upregulation of pancreatic polypeptide-sensitive neuropeptide Y (NPY) receptors in estrogen-induced hypertrophy of the anterior pituitary gland in the Fischer-344 rat

Implants of diethylstilbestrol inducing anterior pituitary prolactinomas in female Fischer-344 rats produced a considerable elevation of high-affinity binding of either rat or human pancreatic polypeptide (hPP). No comparable upregulation of high-affinity binding sites was noted for the ligand [125I](Leu31,Pro34)hPYY (LP-PYY) (masked by 2 nM hPP to force selectivity for the Y1 sites), or of the Y2-selective ligand [125I]hPYY(3-36). The Y5-like sites displayed the rank order of potency of hPP = rPP, hNPY, LP-PYY > pPYY(1-36) > hNPY(2-36) > hPYY(3-36) >> aPP, similar to the previously described rabbit kidney or hypothalamic Y5-like receptors. The PP binding in the anterior pituitary was not sensitive to the Y1-selective non-peptidic antagonist BIBP-3226. The PP binding was highly sensitive to alkali metal cations, and to a N5-substituted amiloride antagonist of sodium transport, but not to a C2-guanido substituted amiloride antagonist of sodium channels. The binding was also sensitive to phospholipase C antagonist U-73122, and to alkylating alpha-adrenergic agonist chloroethylclonidine. Lactotrophs isolated in Percoll gradients after enzymic dispersion of the anterior pituitary gland retained the high-affinity PP binding. Following removal of estrogen implants, the hPP binding sites decreased to very low levels within 3 days, in parallel to the decrease of plasma prolactin.

Ligand association with the rabbit kidney and brain Y1, Y2 and Y5-like neuropeptide Y (NPY) receptors shows large subtype-related differences in sensitivity to chaotropic and alkylating agents

The binding to rabbit kidney or hypothalamic particulates of the subtype-selective neuropeptide Y (NPY) receptor ligands [125I](Leu31,Pro34)hPYY (as Y1 site label at 2 nM human pancreatic polypeptide (hPP)), [125I]-hPYY(3-36) (Y2 label), and [125I]-hPP (Y5 label) displayed great differences in sensitivity to alkylators and chaotropic agents. Sensitivity to a nonionic chaotrope, urea, was much higher for the Y1 binding than for the Y5-like binding or the Y2 binding. The non-selective alkylator N-ethylmaleimide (NEM) and several alkylators selective for aminergic receptors were much more efficacious against the Y1 relative to the Y2 binding. Similar differences could be confirmed with the attachment of Y1 and Y2-selective tracers to CHO cells expressing the cloned guinea-pig Y1 or Y2 receptors. The Y5-like binding was quite insensitive to NEM, but sensitive to chloroethylclonidine (CEC) and prazobind, which were less potent at the Y1, and especially at the Y2 site. The unrestricted-access alkylator 2-aminoethyl methanethiosulfonate inhibited the binding to all subtypes, while the restricted-access agent 2-(trimethylammonium)ethylmethanethiosulfonate poorly inhibited the Y5-like binding, or the guanine nucleotide-insensitive Y2 binding. These results are compatible with an active conformation of the Y5-like site dependent on maintenance of a shared hydrophobic cavity. The Y2 sites resistant to guanosine polyphosphates and restricted-access alkylators were detected mainly in particulates slowly solubilized by cholate at 0-5 degrees C; these sites could be clustered.

FMRFamides exert a unique modulation of rodent pancreatic polypeptide sensitive neuropeptide Y (NPY) receptors

FMRFamide and related peptides (RFamides) were found to inhibit the association binding of iodinated human pancreatic polypeptide ([125I]hPP) to Y5-like neuropeptide Y (NPY) receptor in rodent tissues. An allosteric regulation of the activity of the rodent kidney PP-sensitive neuropeptide Y (NPY) receptor by RFamides was indicated by potency decrease with particle concentration in the inhibition of the association binding of 125I-labeled human pancreatic polypeptide (hPP) by RFamides at rabbit kidney membranes. The competition by C-terminal hexapeptide of hPP (LTRPRY.NH2) did not show such affinity change. The steady-state binding of hPP showed little sensitivity to any of the RFamides tested. The Y1-selective binding of [125I][Leu31,Pro34]hPYY (at 2 nM hPP) was much less sensitive to RFamides than the binding of [125I]hPP, albeit with some differences across tissue or cell types. The binding of Y2-selective agonist 125I-labeled human peptide YY (3-36) was quite insensitive to RFamides. The presence of a unique component in the inhibition of hPP binding by RFamides was further indicated by a degree of antagonism with phospholipase C inhibitor U-73122, and by an only limited cooperation with a N5-amiloride compound, and with alkylator chloroethylclonidine. Change of the chirality of individual residues in the FMRFamide molecule produced a significant reduction of inhibitory potency only with D-Phe in the C-terminal position. Substitution of the (C-3) L-Met by L-Leu greatly increased the inhibitory potency of RFamides relative to otherwise identical congeners. RFamides could act both as ligands of membrane neighbors of the PP receptor, and as competitors of Y5-like NPY receptor epitopes that accommodate the C-terminal aspects of agonist peptides.

Characterization of rabbit kidney and brain pancreatic polypeptide-binding neuropeptide Y receptors: differences with Y1 and Y2 sites in sensitivity to amiloride derivatives affecting sodium transport

Sites sensitive to human and rat pancreatic polypeptides (hPP and rPP) accounted for more than 30% of the specific binding of [125I](Leu31,Pro34) human peptide YY (LP-PYY) in particulates from rabbit kidney cortex, and about 10% of the specific binding in membranes from rabbit hypothalamus. The binding of [125I]hPP or [125I]rPP showed a high-affinity displacement with either hPP, rPP, LP-PYY, neuropeptide Y or peptide YY (Ki below 50 pM for all), while being quite insensitive to Y2-selective ligands. The PP binding had a high sensitivity to alkali cations and inhibitors of phospholipase C, very similar to that of LP-PYY binding 'masked' by excess cold hPP. However, as different from the Y1-like LP-PYY binding, but similar to the binding of the Y2-selective ligand [125I]human peptide YY(3-36) (hPYY(3-36)), the PP binding showed a low sensitivity to guanosine polyphosphates. The PP binding was much more sensitive to N5-substituted amiloride inhibitors of Na+ transport than the binding of LP-PYY, or that of hPYY(3-36). The inhibition of PP binding by N5-substituted amilorides was not enhanced by guanine nucleotides or by phospholipase C blockers. However, pairing of N5-substituted amilorides disproportionately increased the inhibition of hPP binding. Thus, in rabbit kidney or hypothalamus, the high-affinity PP-responding sites share some of the basic properties of the Y1 and Y2 sites, but are distinguished from both by a high sensitivity to compounds affecting sodium transport. These PP/NPY receptors could associate with membrane structures involved in the control of ion balance and osmotic responses.

Characterization of Y1, Y2 and Y5 subtypes of the neuropeptide Y (NPY) receptor in rabbit kidney. Sensitivity of ligand binding to guanine nucleotides and phospholipase C inhibitors

The binding of two peptide YY/neuropeptide Y analogues selective for major subtypes of neuropeptide Y (NPY) receptors was compared in particulates from rabbit kidney cortex employing modulators of activity of G-proteins, phospholipase enzymes, and ion channels. The binding of (Leu31,Pro34)human peptide YY resembled the patterns observed previously for the brain tissue Y1 receptor, exhibiting a high sensitivity to monovalent cations, disulfide disruptors, guanosine polyphosphates and phospholipase C inhibitors. However, this binding was bimodal in response to human pancreatic polypeptide and to peptides selective for the Y2 subtype of the NPY receptor, displaying a large component pharmacologically similar to the brain Y5 receptor. This kidney Y5-like binding largely shared the sensitivity to monovalent cations, guanine nucleotides and phospholipase C inhibitors found for either the kidney or the brain Y1 receptor, and also was activated by Ca2+ ion. Both Y1- and Y5-like binding in the kidney displayed a uniformly low reactivity to a nonpeptidic Y1 antagonist, BIBP-3226, and to a receptor peptide mimetic, mastoparan analogue MAS-7. The kidney Y2 binding shared the low sensitivity to ionic environment observed for the brain Y2 subtype, and was only partially sensitive to guanine nucleotides or to MAS-7. The Y2 liganding had a sensitivity to phospholipase C inhibitors similar to the Y1/Y5 binding. This reactivity was retained in the fraction of the Y2 receptor persisting detergent solubilization in a high-affinity form, which, however, was activated rather than inhibited by G-protein agonists.

Characterization of G protein and phospholipase C-coupled agonist binding to the Y1 neuropeptide Y receptor in rat brain: sensitivity to G protein activators and inhibitors and to inhibitors of phospholipase C

Binding of a Y1-subtype-selective agonist of neuropeptide Y (NPY) receptor, (Leu31,Pro34)human peptide YY (LP-PYY), to particulates from four rat brain areas (parietal cortex area 1, piriform cortex, anterior hypothalamus and hippocampus) showed a distinct response to LP-PYY and PYY, a uniformly low sensitivity to ligands selective for the Y2, Y4 and Y5 NPY receptor subtypes and high sensitivity to a Y1 site-selective antagonist, BIBP-3226. The Y1 binding was sensitive to guanine nucleotide-binding protein (G protein) agonist and antagonist nucleotides, with the rank order of guanosine 5'-O-(thiotriphosphate) (GTP gamma S) > GTP > GDP > guanosine 5'-O-(thiodiphosphate). However, guanine nucleotides did not affect about one third of the specific Y1 binding. Most of Y1 binding could be inhibited by a G protein nucleotide site/docking site receptor mimic, mastoparan analog MAS-7. In all areas examined, the Y1 binding of LP-PYY was little affected by up to 100 microM of the antagonists of K+, Na+ and Ca++ channels, protein kinase C, phospholipase A2, phospholipase D and phosphatidylinositol 3-kinase, phospholipase substrate phospholipids, steroids or detergents. However, the binding was potently inhibited by phospholipase C inhibitors (especially the aminosteroid U-73122), which also dissociated the bound Y1 ligand in steady-state conditions. U-73122 also displaced the Y1 binding insensitive to GTP gamma S. Ligand association with the brain Y1 NPY receptor thus strongly depends on activity of both G proteins and phospholipase C, implying specific interactions of these transducers/effectors with the receptor molecule in ligand binding. A portion of brain Y1 sites could be directly coupled to phospholipase(s) C.

Inflammatory breast carcinoma incidence and survival: the surveillance, epidemiology, and end results program of the National Cancer Institute, 1975-1992

BACKGROUND

Little is known about the cause of inflammatory breast carcinoma (IBC), the most aggressive form of breast cancer. To the authors' knowledge, no studies have investigated whether IBC risk factors are different from those for breast carcinoma overall, and there has been only one report of IBC incidence and survival patterns.

METHODS

The authors used data from the Surveillance, Epidemiology, and End Results program of the National Cancer Institute for the period 1975-1992 to calculate age-adjusted incidence and survival rates for 913 white and 121 African American women with IBC involving dermal invasion of lymphatic ducts and 166,375 white and 13,674 African American women with other types of breast carcinoma (non-IBC).

RESULTS

Between 1975-1977 and 1990-1992, IBC incidence doubled, increasing among whites from 0.3 to 0.7 cases per 100,000 person-years and among African Americans from 0.6 to 1.1 cases. However, rates for African Americans varied due to the small numbers of IBC cases. The twofold increase in IBC incidence was higher than that observed for non-IBC during the same period (27% for African Americans and 25% for whites). IBC patients were significantly younger at diagnosis than non-IBC patients; and among both IBC and non-IBC patients, African Americans were younger than whites. Overall survival was significantly worse for IBC patients than for non-IBC patients and for African Americans than for whites. Among whites, 3-year survival improved more for IBC patients than for non-IBC patients between 1975-1979 and 1988-1992, increasing from 32% to 42% for IBC patients (P=0.0001) and from 80% to 85% for non-IBC patients (P=0.0001).

CONCLUSIONS

The disparities observed in incidence trends and age at diagnosis, particularly according to race, highlight the need for further investigation of the differences between IBC and non-IBC incidence.

Long-term cancer patient survival in the United States

Although survival rates are useful for monitoring progress in the early detection and treatment of cancer and are of particular interest to patients with new diagnoses, there are limited population-based estimates of long-term survival rates. We used data collected by the Surveillance, Epidemiology, and End Results Program for cases diagnosed during 1974-1991 and followed through 1992 to estimate relative survival at 5, 10, and 15 years after diagnosis of cancer of the breast, prostate, colon and rectum, and lung. Relative survival after diagnosis of breast and prostate cancer continued to decline up through 15 years after diagnosis, whereas survival after diagnosis of lung and colon or rectal cancer remained approximately constant after 5 and 10 years, respectively. Age-specific patterns of survival varied by site, stage, and demographics. Among patients with localized breast and prostate cancer, women who were younger than age 45 at breast cancer diagnosis and men who were 75 years and older at prostate cancer diagnosis had the poorest relative survival. Relative survival among lung cancer patients decreased with age at diagnosis, regardless of stage or demographics, and age-specific patterns of relative survival for patients with cancer of the colon and rectum differed according to race. Among white patients diagnosed with cancers of the colon and rectum, relative survival did not vary by age at diagnosis; among black patients older than 45 at diagnosis, relative survival decreased with age. This study provides population-based estimates of long-term survival and confirms black/white, male/female, and stage- and age-specific differences for the major cancers.

Quantification of poliovirus in seawater and sewage by competitive reverse transcriptase--polymerase chain reaction

Reverse transcriptase-polymerase chain reaction (RT-PCR) has been used extensively to detect enteric viruses in environmental samples. Advantages of RT-PCR include its high detection sensitivity and rapid turn-around time. However, unlike traditional cell culture, RT-PCR has not provided quantitation and infectivity information. In this study, we have developed a quantitative RT-PCR method that can be used to determine the amount of poliovirus RNA in environmental samples. An RNA internal standard for poliovirus RT-PCR was designed and obtained through genetic engineering. Serial dilutions of RNA internal standard templates were amplified with a 5'-carboxyfluorescein-labeled poliovirus downstream primer and a nonlabeled poliovirus upstream primer in the RT-PCR. The fluorescent light intensity of labeled RT-PCR products was quantified using an ABI DNA sequencer with GeneScan software. The internal standard was coamplified with poliovirus in the RT-PCR, allowing for enumeration of the poliovirus RNA present in the seawater and sewage samples. This method, using a cloned internal standard and specified primers in the PCR, may be applied to quantify other microorganisms in environmental samples. Although quantitative RT-PCR has begun to be used more extensively for detecting pathogens in clinical samples, the complex nature of many environmental samples has limited the sample range of the effectiveness of quantitative RT-PCR.

Cancer statistics by race and ethnicity

Key findings on cancer incidence and mortality are presented for five racial and ethnic groups in the United States--African Americans, American Indians, Asians and Pacific Islanders, Hispanics, and whites. Information on the prevalence of cancer risk factors and screening examinations among these racial and ethnic groups is also included.

Staphylococcus aureus meningitis--a rare complication of iliacus muscle abscess

Staphylococcus aureus meningitis is a rare but well recognized condition which had a high mortality and incidence of neurological sequelae. It is usually associated with chronic underlying conditions. A case is reported of S. aureus meningitis in a previously healthy young man. The epidemiology, microbiological findings and treatment of this condition are discussed.

The risk of breast cancer following spontaneous or induced abortion

To evaluate the relationship between breast cancer risk and spontaneous and induced abortion, we conducted a detailed descriptive review of 32 epidemiologic studies that provided data by type of abortion and by various measures of exposure to abortion-number of abortions, timing of abortion in relation to first full-term pregnancy, length of gestation, and age at first abortion. Breast cancer risk did not appear to be associated with an increasing number of spontaneous or induced abortions. Our review also suggested that breast cancer risk probably was not related to the other measures of exposure to abortion, and probably did not differ by age or a family history of breast cancer. Finally, the data appeared to suggest a slightly increased risk among nulliparous women, but this tendency was based primarily on studies with a small number of nulliparous women who had had spontaneous or induced abortions. Definitive conclusions about an association between breast cancer risk and spontaneous or induced abortion are not possible at present because of inconsistent findings across studies. Future investigations should consider prospective designs, separate analyses of spontaneous and induced abortions, appropriate referent groups, and adequate adjustment for confounding and effect modification. Future investigations also should attempt to determine whether any increased risks reflect the transient increase in breast cancer risk hypothesized for full-term pregnancy or a causal relationship specific to spontaneous or induced abortion.

Differences in cation sensitivity of ligand binding to Y1 and Y2 subtype of neuropeptide Y receptor of rat brain

The binding of selective ligands to the Y1 subtype of neuropeptide Y receptor in rat brain particulates was promoted by Ca2+ and also stimulated by Sr2+, but reversibly reduced by Ba2+, Mg2+, Mn2+, by the organic polycations neomycin and spermidine, and by chelating agents. The alkali monovalent cations inhibited the Ca(2+)-enabled Y1 subtype binding with some selectivity (Cs+ > or = NH4+ > Li+ > Na+, K+), with half-inhibition between 70-120 mM. The specific Y2 subtype binding was enhanced by all alkaline-earth divalent cations, Mn2+, neomycin and spermidine in the range of 0.1-10 mM, and by alkali cations at up to 100 mM, and also by Na+ salts of the chelators EGTA and EDTA. The large disparity in cation sensitivity indicates substantial differences in the structure of the binding sites of the Y1 and Y2 receptors, predictable from known distinct features of ligand epitopes and of primary structure of the receptors.

Neuropeptide Y Y2 receptors in hypothalamic neuroendocrine areas are up-regulated by estradiol and decreased by progesterone cotreatment in the ovariectomized rat

Central neuropeptide Y (NPY) systems are known to stimulate, via the Y1 subtype of NPY receptor, the release of LHRH that leads to surges of LH. Levels of NPY receptors in relation to the above modulation have not been assessed. This study, therefore, examined profiles of NPY receptors in ovariectomized (Ovx) rats and in Ovx rat treated with estradiol (E2) with or without cotreatment with progesterone (P4). [125I]Human PYY containing proline in position 34 [(Pro 34 )hPYY] was used as the Y1 receptor ligand, and [125 I]human peptide YY-(3-36) [hPYY-(3-36)] was used as the Y2 site ligand. Treatment with E2 over 3 days increased Y2 binding in the preoptic hypothalamus and the medial basal hypothalamus, whereas no changes were found in the lateral anterior hypothalamus or the piriform cortex. Administration of P4 (1.5 mg/animal) on the third day of E2 treatment reduced Y2 binding in both the preoptic hypothalamus and the medial basal hypothalamus to or below the density found in Ovx controls. The Y1 receptor levels and the affinity of either Y1 or Y2 binding did not change appreciably with any of the treatments. No significant changes in the binding of wheat germ agglutinin were found at the time of the largest reduction in Y2 receptor numbers by P4, indicating the absence of a major membrane receptor reduction in response to the progestin. The down-regulation of Y2 sites by P4 preceded and accompanied the surge of serum LH induced by the progestin in E2-treated animals. A short term P4 treatment thus appears to reduce the Y2 tone in hypothalamic areas involved in LHRH secretion. This reduction might reinforce Y1 drives known to stimulate the output of LHRH, and thus contribute to LH release.

Cervical cancer incidence and screening: status report on women in the United States

PURPOSE

Population-based estimates of cervical cancer incidence and screening are described.

DESCRIPTION OF STUDY

Data from the Surveillance Epidemiology and End Results and from the 1992 National Health Interview Survey Cancer Control Supplement were used to examine differences in disease rates, stage at diagnosis, and screening practices among population groups.

RESULTS

The overall age-adjusted incidence rate for invasive cervical cancer was 8.5 per 100,000 women in 1988-1992. Rates for black women were 66% higher than those for white women. At the youngest ages, rates were similar for both races--about 2.0 per 100,000. At older ages, rates diverged, increasing to 17.2 for white women ages 60 to 64 and 47.0 for black women aged 85 and older. Most cervical cancers were diagnosed at the localized stage, and older women and minority women were more likely to be diagnosed with advanced stage disease. Almost 25% of women reported they had not had a Papanicolaou smear test within the past 3 years. Among women younger than 45, whites were more likely than blacks not to have been screened. Among black women, there were regional differences in the use of Papanicolaou test, with those who lived in the South most likely not to be screened.

CLINICAL IMPLICATIONS

Although rates for some groups appear to be converging, disparities still exist. Targeted approaches to screening, follow-up, and treatment are necessary to ensure that trends in cervical cancer incidence continue to improve.

Cancer statistics for African Americans, 1996

Although cancer remains a major public health burden for African Americans, progress is being achieved. For both genders, stomach cancer mortality and mortality related to Hodgkin's disease showed large decreases over the past 30 years. Among African-American females, large decreases in cancer mortality occurred for nonmelanoma skin cancers, rectal cancers, and cervical and other uterine cancers. Tobacco use continues to decline among African Americans and, at present, is significantly lower among African-American youths than among their white counterparts. Despite these successes, additional work remains. Increased patient education regarding self-examinations and improved access to cancer screening are necessary to reduce the high percentage of cancers diagnosed at late stages among African Americans. Improved screening ultimately would increase survival and decrease cancer mortality. Some research has suggested that the increased morbidity and mortality in African Americans are related to poverty, lower education, and inadequate access to care as opposed to inherent racial characteristics. A recent study of black-white differences according to stage at diagnosis of breast cancer confirms some of these factors but also suggests that multiple factors may explain these differences, including mammograms, having a breast examination by a physician, and a history of patient delay. Such observations point to the importance of enacting broad social policies and establishing support mechanisms to diminish the impact of cancer in the African-American community.

Cancer statistics, 1996

The American Cancer Society's Department of Epidemiology and Statistics reports its 30th annual compilation of cancer incidence, survival, and mortality data for the United States and around the world.

Comparison of PCR-generated fragments of the mce gene from Mycobacterium tuberculosis, M. avium, M. intracellulare, and M. scrofulaceum

Nineteen strains representing 13 species of mycobacteria were tested for the ability to serve as PCR templates for the production of a 293-bp fragment of the mycobacterial mce gene. The mce gene is a virulence factor recently sequenced from Mycobacterium tuberculosis. PCR products were obtained for only the species of the Mycobacterium tuberculosis complex (MTC) and the Mycobacterium avium-M. intracellulare-M. scrofulaceum complex. The fragment was sequenced from M. tuberculosis (one strain), M. avium (three strains), M. intracellulare (two strains), and M. scrofulaceum (two strains). Sequence comparisons suggest that the fragments from each of the species are regions that code for a similar product. One of the M. scrofulaceum strains yielded a sequence whose most probable reading frame was truncated by an amber stop codon caused by a single nuclei acid difference from the other sequences. The amino acid sequences from the non-MTC sequences cluster together, displaying fewer differences from each other than from the M. tuberculosis sequence and the truncated M. scrofulaceum sequence. Principal component analysis of the distance matrix displays the clustering of the M. avium and M. intracellulare sequences into single-species clusters. It is concluded that at least one open reading frame of the mce gene is found, although it is discernibly different, in pathogenic mycobacteria other than the MTC.

Central stimulation of oxytocin release in the lactating rat by N-methyl-D-aspartate: requirement for coactivation through non-NMDA glutamate receptors or the glycine coagonist site

Excitatory amino acid (EAA) neurotransmitters participate in the regulation of secretion of several neuropeptides, including oxytocin (OT), via actions at different receptors. In earlier studies, release of OT could be achieved reliably by injection into the supraoptic nucleus (SON) of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)/kainate receptor agonists, but not by treatment with N-methyl-D-aspartate (NMDA) alone. This prompted further examination of the possible role of NMDA receptors in OT release following central coapplication of NMDA and AMPA-site agonists, or of NMDA and agonists active at the glycine coagonist site. The agonists were injected into the right SON, the right paraventricular nucleus (PVN), or into the third ventricle (3V) of nonsuckled lactating rats. Cotreatment with NMDA and AMPA (using doses that alone did not include OT release) elicited a strong OT release in all animals by either the SON or the PVN route, and this was attenuated by pretreatment/cotreatment with specific antagonists of either the NMDA or the AMPA receptor. The SON area or 3V coinjection of NMDA and the NMDA/glycine site agonists glycine or D-serine also induced OT discharges in all animals, while cotreatment in the PVN did not result in uniform OT discharges. This release was potently reduced by cotreatment with the specific NMDA/glycine site antagonist 5, 7-dichlorokynurenate (DCK). L-Serine somewhat increased the frequency of discharge-type response to NMDA, while intra-SON coinjection of L-leucine did not stimulate OT release. D-Serine alone stimulated the release of OT much less than in combination with NMDA, and with no obvious dose dependence. The suckling-induced release of OT was attenuated, but not abolished, by DCK, while PRL release was briefly stimulated by this agent. A physiological role for the NMDA receptor in OT release is clearly supported by these studies. NMDA receptor activation in the lactating rat may result from either an allosteric stimulation by glycine site agonists, or a synergistic interaction with the AMPA/kainate group of excitatory amino acid receptors.

Stimulation of oxytocin release in the lactating rat by a central interaction of alpha 1-adrenergic and alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid-sensitive excitatory amino acid mechanisms

These studies tested for a facilitatory interaction between noradrenergic and excitatory amino acid mechanisms controlling oxytocin (OT) release in the lactating rat. Lactating females were cannulated in the supraoptic nucleus of the hypothalamus (SON) or into the third ventricle and treated with the alpha 1-agonist phenylephrine (PHE) or the glutamate receptor agonist alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA), either alone or together. Treatment with PHE increased plasma OT dose dependently after microinjection into the SON area; strong stimulation also occurred after third ventricle injection of the drug. AMPA caused dose-dependent increases in plasma OT after SON injection. Coinjection of an ineffective or submaximally effective dose of AMPA and a submaximally stimulating dose of PHE produced synergistic OT discharges. OT release in response to the combination of PHE plus AMPA could be abolished by pretreatment/cotreatment with either an alpha 1-adrenergic antagonist or an AMPA receptor antagonist. Moreover, the OT secretory response to the alpha 1-adrenergic agonist PHE alone was attenuated by blockade of AMPA receptors, whereas the OT secretory response to the glutamate agonist AMPA alone was attenuated by blockade of alpha 1-adrenergic receptors. These findings suggest an interaction between norepinephrine and glutamate that may involve pre- and/or postsynaptic mechanisms. As disruption of either noradrenergic or glutamatergic mechanisms is known to impair suckling-induced OT release, the cooperative action of transmitters active at alpha 1-adrenergic and AMPA receptors may be important for the milk ejection reflex.

Stimulation of oxytocin release in the lactating rat by central excitatory amino acid mechanisms: evidence for specific involvement of R,S-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid-sensitive glutamate receptors

To examine whether an excitatory amino acid (EAA) neurotransmitter may influence the secretion of oxytocin (OT), agonists and antagonists selective for three major groups of EAA receptors were microinjected into the area of right supraoptic nucleus (SON) of conscious unrestrained lactating rats. An increase in plasma OT concentration was induced by the EAA receptor agonist R,S-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) and kainic acid, but not by agonists at other EAA receptors, such as N-methyl-D-aspartic acid (NMDA) or the metabotropic agonist (1S,3R)-1-amino-cyclopentane-1,3-dicarboxylic acid. Increasing AMPA doses between 0.1-0.8 nmol/SON progressively increased the percentage of animals showing OT discharges to 100% at the highest dose, whereas the responding animals showed similar elevations of plasma OT regardless of dose. OT release induced by intra-SON AMPA was prevented by treatment with the selective non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione, but not by antagonists of the NMDA receptor. Administration of this antagonist in the third ventricle blocked the release of OT and PRL induced by suckling. The L-type Ca2+ channel antagonist nimodipine and the Na+ channel inhibitor 3-amino-N-(aminoiminomethyl)5-(N-ethyl-N-isopropyl)6-chloropyra zinecarboxamide produced an additive blockade of AMPA-induced OT release, whereas the N-type Ca2+ channel-preferring antagonist omega-conotoxin GVIA had no effect. These findings suggest that an EAA, most likely glutamate, participates in the physiological regulation of OT release in the lactating rat via actions at an AMPA/kainate receptor subtype that gates Na+ and Ca2+.

Relationship of thermal and chemical tolerance to transepithelial transport by cultured flounder renal epithelium

We tested the effects of mild heat shock (MHS) on tolerance of epithelial transport processes to a chemical inhibitor and, reciprocally, chemical stress effects on tolerance to severe thermal stress. Flounder renal tubules were cultured as monolayers on native collagen for 12 to 14 days at 22 degrees C and mounted in Ussing chambers in which transepithelial electrical characteristics and unidirectional [35S]sulfate fluxes were measured. 2,4-dichlorophenoxyacetic acid (0.5 mM) lowered net active sulfate secretion 25% (93.6 +/- 7.64-69.0 +/- 9.08 nmol/cm2/hr); MHS (27 degrees C for 6 hr followed by 1.5 hr at 22 degrees C) prevented this inhibition (92.4 +/- 5.72 nmol/cm2/hr) and stimulated transport 30% (125.7 +/- 11.06 nmol/cm2/hr). Cycloheximide or actinomycin D prevented the enhancing and protective effects of MHS. Preincubation in 100 microM ZnCl2 for 6 hr at 22 degrees C followed by 1.5 hr in zinc-free medium (mild zinc stress) enhanced net sulfate flux, protected transport from severe heat stress (32 degrees C for 1.5 hr followed by 1.5 hr at 22 degrees C) and prevented 2,4-dichlorophenoxyacetic acid inhibition in a manner similar to MHS. Mild zinc shock induced heat shock protein synthesis the same as MHS. Cycloheximide prevented the mild zinc shock effect on transport. The data show that thermal or chemical stressors can independently induce tolerance of transepithelial transport to both thermal and chemical insults and that stress-induced "protection" is due to enhancement of normal function rather than prevention of damage.

Mutation of the Ki-ras protooncogene in human endometrial hyperplasia and carcinoma

Previous studies have demonstrated that some human endometrial carcinomas contain an activating point mutation in codon 12 of the Ki-ras protooncogene. To examine the hypothesis that this mutation may occur at an earlier stage of neoplastic progression in the endometrium, we analyzed 89 samples of premalignant endometrial hyperplasia and an additional 84 samples of endometrial carcinoma for point mutations of Ki-ras codon 12. Mutations were found in all three types of endometrial hyperplasia, simple, complex, and atypical, with no clear evidence of a differential distribution in any particular type. Furthermore, the overall incidence of Ki-ras mutations in the hyperplasia specimens (16%) was similar to the incidence detected in carcinomas (18%), indicating that ras mutation may represent an early event in a subset of endometrial carcinomas. When the tissue samples were segregated as to country of origin, the frequency of this mutation was approximately 2-fold higher in hyperplasia and carcinoma samples from Japan than from the United States, where the incidence, clinicopathological characteristics, and risk factors for endometrial carcinoma differ dramatically. There was no apparent correlation, however, between ras mutation and any pathological, histological, or clinical parameter examined, except survival. The presence of a ras mutation was inversely associated with death from disease, suggesting that this molecular feature may characterize a subset of endometrial carcinomas with a good prognosis.

Central stimulation of oxytocin release in the lactating rat: interaction of neuropeptide Y with alpha-1-adrenergic mechanisms

The possible cooperation of neuropeptide Y (NPY) and alpha-1-adrenergic mechanisms in the release of oxytocin (OT) in conscious, nonsuckled lactating rats was examined following microinjections of NPY and its analogs and/or alpha-adrenergic drugs into the supraoptic nucleus (SON) or anterior paraventricular nucleus/anterior commissural nucleus (PVN/ACN). The alpha-1-adrenergic agonist phenylephrine dose dependently increased plasma OT after injection into the SON or the PVN/ACN, and this was prevented by treatment with the specific alpha-alpha-1-adrenergic receptor antagonist prazosin, but not by the alpha-2 antagonist rauwolscine. The alpha-2-adrenergic agonist clonidine did not increase plasma OT. Injection of NPY or of the related peptide YY (PYY) alone into the SON or the PVN/ACN also dose dependently increased plasma OT; this was also significantly attenuated by prazosin. Plasma OT responses to NPY and PYY differed significantly in dynamics and duration, which may be related to large differences found in the patterns of displaceable binding of [125I]NPY and [125I]PYY to hypothalamic membranes. The stimulatory action of NPY was mimicked by a preferential Y-1 receptor agonist, but not by an agonist of the Y-2 NPY receptor. Coinjection of NPY or PYY and phenylephrine into either the SON or the PVN/ACN area produced a greater than additive discharge of OT, especially in the SON. This increase was mostly due to a markedly enhanced initial release of OT, and was also completely eliminated by prazosin. The NPY-alpha-1 interaction in stimulating plasma OT was not mediated by direct binding of the peptides to alpha-1-adrenergic receptor sites. These results indicate that 1) the stimulatory noradrenergic influence on OT secretion in the lactating rat is mediated by the alpha-1 adrenergic receptor via an action in the PVN/ACN and SON; 2) NPY also stimulates OT secretion in the lactating rat through the Y-1 receptor subtype in the PVN/ACN and SON; 3) NPY markedly enhances the OT secretory responses to alpha-1 receptor stimulation, particularly in the SON. The cooperative stimulation by NE and NPY may be of physiological importance in mediating the episodic release of OT in response to suckling.

Foods perceived by adults as causing adverse reactions

This study was undertaken to identify differences in offending foods reported by 45 patients with classic symptoms of food allergy and/or subjective food-related complaints not traditionally associated with food allergy. On the basis of a comprehensive clinical history, skin testing, and double-blind food challenges, patients were diagnosed as having confirmed (n = 22) or unconfirmed (n = 23) adverse reactions to foods. The majority of patients in both groups were women-17 of those with confirmed reactions and 21 of those with unconfirmed reactions. Individuals with confirmed reactions were significantly younger, 34.8 +/- 10.9 years, than those with unconfirmed reactions, 41.5 +/- 9.6 years. The symptoms and reaction patterns of adults with confirmed reactions were generally consistent with immunoglobulin E-mediated food hypersensitivity. Individuals with unconfirmed reactions were more likely to report frequently occurring, delayed-onset symptoms of a nonspecific nature, and they had an average of five times as many foods causing adult-onset symptoms than those with confirmed reactions. Adults with confirmed reactions more often reported common food allergens such as tree nuts, legumes, and crustaceans; those with unconfirmed reactions were more apt to name foods not commonly implicated in adult food allergies confirmed by conventional diagnostic methods. The types of offending foods reported suggested that individuals with unconfirmed reactions were influenced by the popular news media and clinical ecology-oriented literature. Their use of nutrition supplements was consistent with the attitude of health activism. Such individuals may seek nontraditional health care or adopt questionable dietary practices. Individuals with adverse food reactions of a nonspecific nature pose challenging problems to dietitians.