Selective effects of a morphine conjugate vaccine on heroin and metabolite distribution and heroin-induced behaviors in rats.

Morphine conjugate vaccines have effectively reduced behavioral effects of heroin in rodents and primates. To better understand how these effects are mediated, heroin and metabolite distribution studies were performed in rats in the presence and absence of vaccination. In non-vaccinated rats 6-monoacetylmorphine (6-MAM) was the predominant opioid in plasma and brain as early as 1 minute after i.v. administration of heroin and for up to 14 minutes. Vaccination with morphine conjugated to keyhole limpet hemocyanin (M-KLH) elicited high titers and concentrations of antibodies with high affinity for heroin, 6-MAM, and morphine. Four minutes after heroin administration vaccinated rats showed substantial retention of all three opioids in plasma compared to controls and reduced 6-MAM and morphine, but not heroin, distribution to brain. Administration of 6-MAM rather than heroin in M-KLH vaccinated rats showed a similar drug distribution pattern. Vaccination reduced heroin-induced analgesia and blocked heroin-induced locomotor activity throughout 2 weeks of repeated testing. Higher serum opioid-specific antibody concentrations were associated with higher plasma opioid concentrations, lower brain 6-MAM and morphine concentrations, and lower heroin-induced locomotor activity. Serum antibody concentrations over 0.2 mg/ml were associated with substantial effects on these measures. These data support a critical role for 6-MAM in mediating the early effects of i.v. heroin and suggest that reducing 6-MAM concentration in brain is essential to the efficacy of morphine conjugate vaccines.

Involvement of mouse Mlh1 in DNA mismatch repair and meiotic crossing over.

Mice that are deficient in either the Pms2 or Msh2 DNA mismatch repair genes have microsatellite instability and a predisposition to tumours. Interestingly, Pms2-deficient males display sterility associated with abnormal chromosome pairing in meiosis. Here mice deficient in another mismatch repair gene, Mlh1, possess not only microsatellite instability but are also infertile (both males and females). Mlh1-deficient spermatocytes exhibit high levels of prematurely separated chromosomes and arrest in first division meiosis. We also show that Mlh1 appears to localize to sites of crossing over on meiotic chromosomes. Together these findings suggest that Mlh1 is involved in DNA mismatch repair and meiotic crossing over.

Tumour susceptibility and spontaneous mutation in mice deficient in Mlh1, Pms1 and Pms2 DNA mismatch repair.

Germline mutations in the human MSH2, MLH1, PMS2 and PMS1 DNA mismatch repair (MMR) gene homologues appear to be responsible for most cases of hereditary non-polyposis colorectal cancer (HNPCC; refs 1-5). An important role for DNA replication errors in colorectal tumorigenesis has been suggested by the finding of frequent alterations in the length of specific mononucleotide tracts within genes controlling cell growth, including TGF-beta receptor type II (ref. 6), BAX (ref. 7) and APC (ref. 8). A broader role for MMR deficiency in human tumorigenesis is implicated by microsatellite instability in a fraction of sporadic tumours, including gastric, endometrial and colorectal malignancies. To better define the role of individual MMR genes in cancer susceptibility and MMR functions, we have generated mice deficient for the murine homologues of the human genes MLH1, PMS1 and PMS2. Surprisingly, we find that these mice show different tumour susceptibilities, most notably, to intestinal adenomas and adenocarcinomas, and different mutational spectra. Our results suggest that a general increase in replication errors may not be sufficient for intestinal tumour formation and that these genes share overlapping, but not identical functions.

Flavor-specific enhancement of electronic cigarette liquid consumption and preference in mice.

BACKGROUND: The use of electronic cigarettes has increased over the past decade. To determine how the abuse liability of electronic cigarette liquids (e-liquids) differs from nicotine alone, and to determine the impact of flavor, we compared nicotine-containing fruit- and tobacco-flavored e-liquids, and their nicotine-free versions, to nicotine alone in mouse models of oral consumption, reward and aversion. METHODS: Adult male C57BL/6 J mice voluntarily consumed oral nicotine, equivalent nicotine concentrations of fruit- and tobacco-flavored e-liquid, and equivalent dilutions of the nicotine-free versions in 2-bottle choice tests. Conditioned place preference and place aversion were assessed with peripherally administered e-liquids or nicotine. Serum nicotine and cotinine levels were measured after subcutaneous injections of e-liquid or nicotine. RESULTS: Mice showed higher consumption and preference for the fruit-flavored e-liquid compared with nicotine alone. This increase was not due to the flavor itself as consumption of the nicotine-free fruit-flavored e-liquid was not elevated until the highest concentration tested. The increased consumption and preference were not observed with the tobacco-flavored e-liquid. The conditioned place preference, place aversion and nicotine pharmacokinetics of the fruit-flavored e-liquid were not significantly different from nicotine alone. CONCLUSIONS: Our data suggest that fruit, but not tobacco flavor, increased the oral consumption of e-liquid compared with nicotine alone. Moreover, this enhancement was not due to increased consumption of the flavor itself, altered rewarding or aversive properties after peripheral administration, or altered pharmacokinetics. This flavor-specific enhancement suggests that some flavors may lead to higher nicotine intake and increased use of e-liquids compared with nicotine alone.

Similar precipitated withdrawal effects on intracranial self-stimulation during chronic infusion of an e-cigarette liquid or nicotine alone.

The FDA recently extended their regulatory authority to electronic cigarettes (ECs). Because the abuse liability of ECs is a leading concern of the FDA, animal models are urgently needed to identify factors that influence the relative abuse liability of these products. The ability of tobacco products to induce nicotine dependence, defined by the emergence of anhedonia and other symptoms of nicotine withdrawal following cessation of their use, contributes to tobacco abuse liability. The present study compared the severity of precipitated withdrawal during chronic infusion of nicotine alone or nicotine-dose equivalent concentrations of three different EC refill liquids in rats, as indicated by elevations in intracranial self-stimulation (ICSS) thresholds (anhedonia-like behavior). Because these EC liquids contain constituents that may enhance their abuse liability (e.g., minor alkaloids), we hypothesized that they would be associated with greater withdrawal effects than nicotine alone. Results indicated that the nicotinic acetylcholine receptor antagonist mecamylamine precipitated elevations in ICSS thresholds in rats receiving a chronic infusion of nicotine alone or EC liquids (3.2mg/kg/day, via osmotic pump). Magnitude of this effect did not differ between formulations. Our findings indicate that nicotine alone is the primary CNS determinant of the ability of ECs to engender dependence. Combined with our previous findings that nicotine alone and these EC liquids do not differ in other preclinical addiction models, these data suggest that product standards set by the FDA to reduce EC abuse liability should primarily target nicotine, other constituents with peripheral sensory effects (e.g. flavorants), and factors that influence product appeal (e.g., marketing).

Double dissociation in the neural substrates of acute opiate dependence as measured by withdrawal-potentiated startle.

The basolateral amygdala and portions of the "extended" amygdala (i.e. central nucleus of the amygdala, bed nucleus of the stria terminalis and shell of the nucleus accumbens) have been implicated in the aversive aspects of withdrawal from chronic opiate administration. Given that similar withdrawal signs are observed following a single opiate exposure, these structures may also play a role in "acute opiate dependence." In the current study, drug-naïve rats underwent naloxone-precipitated withdrawal from acute morphine (10 mg/kg) exposure on two successive days. On either the first or second day of testing, the basolateral amygdala, central nucleus of the amygdala, bed nucleus of the stria terminalis, or nucleus accumbens was temporarily inactivated immediately prior to naloxone injection by microinfusion of the glutamatergic alpha-amino-3-hydroxy-5-methyl-4-isoxazole proprionic acid receptor antagonist 1,2,3,4-tetrahydro-6-nitro-2,3-dioxo-benzo(f)quinoxaline-7-sulfonamide (3 microg/0.5 microl). On the first day, inactivation of the basolateral amygdala, central nucleus of the amygdala, or bed nucleus of the stria terminalis, but not the nucleus accumbens blocked withdrawal-potentiated startle, a behavioral measure of the anxiogenic effects of withdrawal. On the second day, inactivation of the nucleus accumbens, but not the basolateral amygdala, central nucleus of the amygdala, or bed nucleus of the stria terminalis disrupted the withdrawal effect. Effects of structural inactivations on withdrawal-potentiated startle were not influenced by differences in withdrawal severity on the two days of testing. A fear-potentiated startle procedure provided functional confirmation of correct cannulae placement in basolateral amygdale- and central nucleus of the amygdala-implanted animals. Our findings indicate a double dissociation in the neural substrates of withdrawal-potentiated startle following a first versus second morphine exposure, and may reflect a reorganization of the neural circuitry underlying the expression of withdrawal-induced negative affect during the earliest stages of opiate dependence.

The imaging features of gastrointestinal stromal tumours.

Gastrointestinal stromal tumours (GISTs) are a rare group of mesenchymal neoplasms that occur predominantly in the gastrointestinal tract. Previously GISTs were classified as smooth muscle tumours referred to as leiomyomas, leiomyosacromas or leiomyoblastomas. However, with the advent of immunohistochemistry, GISTs are now defined by the identification of cKit positivity. This is now used to select patients with metastatic disease who may respond to chemotherapeutic agents such as the tyrosine kinase inhibitor, STI-571. In this pictorial essay we have attemped to describe the range of imaging findings of GISTs that can suggest a pre-biopsy diagnosis.

Enhanced intestinal adenomatous polyp formation in Pms2-/-;Min mice.

Analysis of two human familial cancer syndromes, hereditary nonpolyposis colorectal cancer and familial adenomatous polyposis, indicates that mutations in either one of four DNA mismatch repair gene homologues or the adenomatous polyposis coli (APC) gene, respectively, are important for the development of colorectal cancer. To further investigate the role of DNA mismatch repair in intestinal tumorigenesis, we generated mice with mutations in both Apc and the DNA mismatch repair gene, Pms2. Whereas Pms2-deficient mice do not develop intestinal tumors, mice deficient in Pms2 and heterozygous for Min, an allele of Apc, develop approximately three times the number of small intestinal adenomas and four times the number of colon adenomas relative to Min and Pms2+/-;Min mice. Although Pms2 deficiency clearly increases adenoma formation in the Min background, histological analysis indicated no clear evidence for progression to carcinoma.

An Unusual "Collision Tumour" of the Prostate Gland and Rectum.

Collision tumours of two different histopathological processes are rare. We describe a case of a patient with known low grade prostate adenocarcinoma developing a rectal GIST, which was diagnosed with combined imaging modalities of MR and ultrasound and confirmed by transrectal ultrasound guided biopsy.

Abuse liability assessment of an e-cigarette refill liquid using intracranial self-stimulation and self-administration models in rats.

BACKGROUND: The popularity of electronic cigarettes (ECs) has increased dramatically despite their unknown health consequences. Because the abuse liability of ECs is one of the leading concerns of the Food and Drug Administration (FDA), models to assess it are urgently needed to inform FDA regulatory decisions regarding these products. The purpose of this study was to assess the relative abuse liability of an EC liquid compared to nicotine alone in rats. Because this EC liquid contains non-nicotine constituents that may enhance its abuse liability, we hypothesized that it would have greater abuse liability than nicotine alone. METHODS: Nicotine alone and nicotine dose-equivalent concentrations of EC liquid were compared in terms of their acute effects on intracranial self-stimulation (ICSS) thresholds, acquisition of self-administration, reinforcing efficacy (i.e., elasticity of demand), blockade of these behavioral effects by mecamylamine, nicotine pharmacokinetics and nicotinic acetylcholine receptor binding and activation. RESULTS: There were no significant differences between formulations on any measure, except that EC liquid produced less of an elevation in ICSS thresholds at high nicotine doses. CONCLUSIONS: Collectively, these findings suggest that the relative abuse liability of this EC liquid is similar to that of nicotine alone in terms of its reinforcing and reinforcement-enhancing effects, but that it may have less aversive/anhedonic effects at high doses. The present methods may be useful for assessing the abuse liability of other ECs to inform potential FDA regulation of those products.

Novel isoforms of CaBP 33/37 (annexin V) from mammalian brain: structural and phosphorylation differences that suggest distinct biological roles.

Two calcium-dependent phospholipid- and membrane-binding proteins have been purified from bovine brain. These are termed CaBP33 and CaBP37. Complete sequence analysis has revealed that these two proteins are isoforms of annexin V. Despite an apparent difference of 4 kDa between the two proteins on SDS-PAGE, only two amino-acid substitutions were found. These are, in CaBP33, Ser-36 and Lys-125 and in CaBP37, Thr-36 and Glu-125. This corresponds to a mass difference of 15 Da. This was confirmed by electrospray mass spectrometric analysis. Both isoforms can be phosphorylated substoichiometrically in vitro by protein kinase C at residue Thr-22.

Localization and structure of the muscarinic receptor ligand binding site.

A conserved aspartic acid residue in transmembrane helix 3 of the muscarinic acetylcholine receptors is important in binding the headgroup of muscarinic ligands. This acidic amino acid probably points into a relatively hydrophilic cavity whose walls are formed by the amphipathic transmembrane helices of the receptor. Amino acid side chains within this cavity contribute to ligand binding.

Cyclosporin A directly inhibits human B-cell proliferation by more than a single mechanism.

Cyclosporin A (CsA) is a potent immunosuppressive agent that inhibits T-cell proliferation and lymphokine production. There is less information on the direct effect of CsA on B-cells. We investigated the proliferative responses of human tonsillar B-lymphocytes to a "T dependent" mitogen, pokeweed mitogen (PWM), and to a "T independent" mitogen, Staphylococcus aureus (SA). Both responses were strongly inhibited by CsA. Nonspecific cytotoxicity was ruled out, and the inhibition was not reversed by adding IL1, IL2, or BCGF individually or in combination. Maximal inhibition of the PWM response occurred when CsA was added early in the culture period. Cyclosporin A added 18 hours after the start of culture was less effective, and adding CsA after 36 hours resulted in only minimal inhibition. However, with SA as mitogen, addition after 36 hours still affected substantial inhibition. These results, on the time of action and resistance to reversal by exogenous growth factors, suggest that CsA can directly inhibit human B-cells by a mechanism similar to its action on T-lymphocytes, blocking an early event critical to entry into cell cycle, but an additional mechanism of inhibition later in the cell cycle may also operate when the proliferative signal is provided by the T-independent mitogen SA.

Sequence analysis of the cloned streptococcal cell surface antigen I/II.

The gene spa P (formerly designated as spa P1) encoding the Mr 185,000 surface antigen (I/II) of Streptococcus mutans, serotype c (NG5), has been sequenced. The gene (4683 bp) encodes a protein of 1561 amino acid residues including putative signal peptide (residues 1-38) and transmembrane (residues 1537-1556) sequences. The N-terminal region (60-550) has alanine-rich repeats and is predicted to be alpha-helical. However, the C-terminal region (800-1540) is proline-rich and favours an extended structure. Except for a short central variable region the sequences appear to be highly conserved for S. mutans serotype c. N-Terminal sequencing of separated antigen I and antigen II polypeptides suggests that the former represents the N-terminal and the latter the C-terminal portions of the intact antigen.

Enumeration of lymphocyte subpopulations by immunofluorescent staining of whole blood smears.

A simple and rapid technique for the enumeration of lymphocyte subpopulations by immunofluorescent staining of blood smears is described. The extremely small volumes of blood required make the technique particularly suitable for samples from paediatric patients. Results compare closely with conventional staining of lymphocytes in suspension.

Comparison of the clinic microscopy laboratory with the cytopathology laboratory in the detection of malignant cells in body fluids.

The clinical microscopy (fluids) laboratory evaluates almost every body fluid that is obtained in the hospital. Because the fluids laboratory functions at all hours, it is often the first laboratory to receive a body fluid. In addition to its primary purpose of quantitating categories of cells, the medical technologist in this laboratory has an opportunity to identify malignant cells. To our knowledge, no formal study has ever been undertaken to evaluate the performance of the fluids laboratory in detecting malignancy. The authors therefore retrospectively identified 928 body fluids (pleural, peritoneal, cerebrospinal, and miscellaneous) over a 2-year period that had undergone simultaneous cytologic examination in our cytopathology laboratory and body fluid analysis in our fluids laboratory. Of these, a cytologic diagnosis of malignancy was made by the cytopathology laboratory in 107 cases; 821 were considered to be benign. No false-positive results were rendered by the fluids laboratory (100% specificity), but only 26 of the 107 malignant cases were identified (24% sensitivity); the overall accuracy was 93%. Factors contributing to the inability of the fluids laboratory to identify malignant cells included (1) too few cells to warrant a cytocentrifuge preparation, especially in cerebrospinal fluid specimens; (2) differences in the processing of specimens; (3) differences in staining procedures; and (4) differences in the training of personnel. The authors conclude that although the fluids laboratory correctly identifies neoplastic cells in approximately one fourth of the cases in which they are present, it should not be expected to detect malignant cells in every cytologically malignant case.(ABSTRACT TRUNCATED AT 250 WORDS)

Steroid cell tumor of the ovary in a child.

An 8-year-old girl exhibited severe, progressive virilization of 2 years' duration associated with markedly elevated circulating testosterone concentrations. Based on her initial clinical presentation and results of a chemical evaluation, she was originally thought to have non-classic 21-hydroxylase deficiency, but her condition did not respond to corticosteroid therapy. Further evaluation confirmed the presence of an ovarian neoplasm. The excised ovary contained an attached gray-brown mass. Light microscopic and ultrastructural examination revealed the mass to be a steroid cell tumor. Because Reinke's crystals were not present, it was designated to be a steroid cell tumor not otherwise specified. This case represents one of 22 reported cases of steroid cell tumor occurring in children described in the literature, most of which have been associated with heterosexual precocity. To our knowledge, steroid cell tumors are benign when they occur in prepubertal children. Although they are rare, steroid cell tumors of the ovary should be considered in cases of childhood virilization.

Bone marrow changes associated with recombinant granulocyte-macrophage and granulocyte colony-stimulating factors. Discrimination of granulocytic regeneration.

The hematopoietic growth factors recombinant human granulocyte-macrophage colony-stimulating factor and recombinant human granulocyte colony-stimulating factor are associated with changes of the bone marrow. To evaluate the morphologic features and to differentiate them from leukemia, bone marrow specimens from 12 patients who had been treated with one of these agents were evaluated. The bone marrow displayed marked promyelocytic hyperplasia and a less striking increased percentage of myeloblasts. In each of the 11 patients without leukemia at the time of bone marrow biopsy, the percentage of promyelocytes in the bone marrow was greater than that of myeloblasts. Cytologic features of stimulated regeneration included diffuse cytoplasmic hypergranulation of immature neutrophilic precursors that had prominent perinuclear spherical clear areas representing the Golgi zones. With consideration of bone marrow composition and careful attention to cytologic detail, the distinction of bone marrow regeneration from acute leukemia can be made in most patients who are being treated with recombinant hematopoietic growth factors.

Rhabdoid cells in peritoneal fluid. A case report.

BACKGROUND: Rhabdoid tumor is an aggressive, malignant renal neoplasm of infants. Many extrarenal sites have been documented. CASE: A poorly differentiated carcinoma of the ovary with rhabdoid features occurred in a 36-year-old woman. The peritoneal fluid contained numerous malignant cells with rhabdoid features. Electron microscopy and immunocytochemistry corroborated the rhabdoid nature of the cells. CONCLUSION: Rhabdoid cells can be distinguished from other neoplasms with similar cytologic features by ancillary studies and clinical history.