Burden of arrhythmias in patients with obstructive sleep apnea and its impact on mortality: a descriptive study from the National Inpatient Sample

Background

Obstructive sleep apnea (OSA) accounts for significant mortality and morbidity worldwide. A limited but emerging literature has revealed increased risk of sudden cardiac death in patients with OSA. There is paucity of data on arrhythmia burden in patients with OSA, particularly in hospitalized patients.

Purpose

Therefore, we sought to study the prevalence of atrial and ventricular arrhythmias among hospitalized patients with OSA and examine its impact on sudden cardiac death and in-hospital mortality.

Methods

All patients over 18 years of age with OSA were extracted from the National Inpatient Sample (NIS) from 2009–10 using 9th revision of International Classification of Diseases (ICD-9) code 327.23. Demographic data, hospital characteristics, comorbid conditions, and arrhythmia burden including different types of arrhythmia were identified. Clinical outcomes were in-hospital mortality, length of stay and sudden cardiac death. Logistic regression analysis was performed to determine the impact of arrhythmia on in-hospital mortality in patients with OSA. Hospital level discharge weights provided by NIS were used to obtain national estimates of OSA hospitalizations.

Results

OSA was prevalent in 2.8% (n=1,114,297) of all hospitalizations among which 20.1% had any arrhythmia (n=223,974). Patients with arrhythmia were older, more likely to be males, and had higher prevalence of risk factors and comorbid conditions except for chronic liver disease, and smoking (p<0.0001 for all). Arrhythmia burden analysis revealed increase prevalence of both atrial and ventricular arrhythmia in patients with OSA compared to general population. In-hospital mortality (3.48% vs 1.27%; p<0.0001), length of hospital stay (6.4±0.1 vs 5±0.1; p<0.001) and sudden cardiac death (1.34% vs 0.4%; p<0.0001) were higher in OSA patients with arrhythmia compared to OSA patients without arrhythmia. Presence of arrhythmia in OSA patients was associated with increased in-hospital mortality in both unadjusted [OR 2.79 (2.62–2.98); p<0.001] and multivariable model adjusted for all risk factors and comorbid conditions [OR 1.83 (1.69–1.98); p<0.001].

Conclusion

Arrhythmia burden was higher in patients with OSA compared to the general population. Presence of arrhythmia among OSA patients was independently associated with increased in-hospital mortality and longer hospital stays. Routine evaluation to assess arrhythmia burden in patients in OSA could be a potential target to decrease sudden cardiac death in this high risk population.

Funding Acknowledgement

Type of funding sources: None.

Surgical strategy for the treatment of sporadic medullary thyroid carcinoma: our experience

BACKGROUND

Medullary thyroid carcinoma (MTC) is a rare disease which accounts for approximately 5-9% of all thyroid cancers and originates from the calcitonin-screening parafollicular C cells. MTC can be divided into two subgroups: sporadic (75%) or inherited (25%). The majority of patients with invasive MTC have metastasis to regional lymph nodes at the time of diagnosis, as evidenced by the frequent finding of persistently elevated calcitonin levels after thyroidectomy and the high rates of recurrence in the cervical lymph nodes reported in retrospective studies.

OBJECTIVES

The purpose of the study is to review our single institution's experience with MTC since 1998 and to evaluate surgical strategy, patterns of lymph node metastases and calcitonin response to compartment-oriented lymphadenectomy in patients with primary or recurrent sporadic medullary thyroid carcinoma.

METHODS

A retrospective review of 26 patients treated for MTC at the "Antonio Cardarelli" Hospital referral center, in Naples, between 1998 and 2012. There were 18 female and 8 male patients, median age at presentation was 55 years, and median follow-up for survivors was 5 years. Total thyroidectomy was performed in all 26 patients; central compartment (CC) node dissection (level VI) in 12 (46%) patients; central plus lateral compartment (LC) node dissection (levels II, III, and IV) in 7 (27%) patients. 4 patients (15%) underwent reoperation for loco-regional recurrent/persistent MTC. Results. After a median post-surgical follow-up of 5 years (range 1-10 years), 63 % of patients were living disease-free, 15% were living with disease and/or persistently elevated calcitonin levels after surgery, 11% were deceased due to MTC and 11 % were lost to follow-up.

CONCLUSIONS

We agree with most authors advocating for a total thyroidectomy and prophylactic central neck dissection in the setting of clinically detected MTC. Lateral neck dissection may be best reserved for patients with positive preoperative imaging. Nevertheless MTC has a high rate of lymph node metastases that are sub optimally detected preoperatively in the central compartment by neck ultrasound or intra-operatively by the surgeon, and reoperation is associated with a higher rate of surgical complications. In our limited experience, patients with thyroid confined nodular pathology, without nodal disease and unknown preoperative diagnosis of MTC, underwent only total thyroidectomy with a good prognosis.

The interaction of PKN3 with RhoC promotes malignant growth

PKN3 is an AGC-family protein kinase implicated in growth of metastatic prostate cancer cells with phosphoinositide 3-kinase pathway deregulation. The molecular mechanism, however, by which PKN3 contributes to malignant growth and tumorigenesis is not well understood. Using orthotopic mouse tumor models, we now show that inducible knockdown of PKN3 protein not only blocks metastasis, but also impairs primary prostate and breast tumor growth. Correspondingly, overexpression of exogenous PKN3 in breast cancer cells further increases their malignant behavior and invasiveness in-vitro. Mechanistically, we demonstrate that PKN3 physically interacts with Rho-family GTPases, and preferentially with RhoC, a known mediator of tumor invasion and metastasis in epithelial cancers. Likewise, RhoC predominantly associates with PKN3 compared to its closely related PKN family members. Unlike the majority of Rho GTPases and PKN molecules, which are ubiquitously expressed, both PKN3 and RhoC show limited expression in normal tissues and become upregulated in late-stage malignancies. Since PKN3 catalytic activity is increased in the presence of Rho GTPases, the co-expression and preferential interaction of PKN3 and RhoC in tumor cells are functionally relevant. Our findings provide novel insight into the regulation and function of PKN3 and suggest that the PKN3-RhoC complex represents an attractive therapeutic target in late-stage malignancies.

Tipin-replication protein A interaction mediates Chk1 phosphorylation by ATR in response to genotoxic stress

Mammalian Timeless is a multifunctional protein that performs essential roles in the circadian clock, chromosome cohesion, DNA replication fork protection, and DNA replication/DNA damage checkpoint pathways. The human Timeless exists in a tight complex with a smaller protein called Tipin (Timeless-interacting protein). Here we investigated the mechanism by which the Timeless-Tipin complex functions as a mediator in the ATR-Chk1 DNA damage checkpoint pathway. We find that the Timeless-Tipin complex specifically mediates Chk1 phosphorylation by ATR in response to DNA damage and replication stress through interaction of Tipin with the 34-kDa subunit of replication protein A (RPA). The Tipin-RPA interaction stabilizes Timeless-Tipin and Tipin-Claspin complexes on RPA-coated ssDNA and in doing so promotes Claspin-mediated phosphorylation of Chk1 by ATR. Our results therefore indicate that RPA-covered ssDNA not only supports recruitment and activation of ATR but also, through Tipin and Claspin, it plays an important role in the action of ATR on its critical downstream target Chk1.

Discovery of 4-(benzylaminomethylene)isoquinoline-1,3-(2H,4H)-diones and 4-[(pyridylmethyl)aminomethylene]isoquinoline-1,3-(2H,4H)-diones as potent and selective inhibitors of the cyclin-dependent kinase 4

The series of 4-(benzylaminomethylene)isoquinoline-1,3-(2H,4H)-dione and 4-[(pyridylmethyl)aminomethylene]isoquinoline-1,3-(2H,4H)-dione derivatives reported here represents a novel class of potential antitumor agents, which potently and selectively inhibit CDK4 over CDK2 and CDK1. In the benzylamino headpiece, a 3-OH substituent is required on the phenyl ring for CDK4 inhibitory activity, which is further enhanced when an iodo, aryl, heteroaryl, t-butyl, or cyclopentyl substituent is introduced at the C-6 position of the isoquinoline-1,3-dione core. To circumvent the metabolic liability associated with the phenolic OH group on the 4-substituted 3-OH phenyl headpiece, we take two approaches: first, introduce a nitrogen o- or p- to the 3-OH group in the phenyl ring; second, replace the phenyl headpiece with N-substituted 2-pyridones. We present here the synthesis, SAR data, metabolic stability data, and a CDK4 mimic model that explains the binding, potency, and selectivity of our CDK4 selective inhibitors.

4-(Phenylaminomethylene)isoquinoline-1,3(2H,4H)-diones as potent and selective inhibitors of the cyclin-dependent kinase 4 (CDK4)

The cyclin-dependent kinases (CDKs), as complexes with their respective partners, the cyclins, are critical regulators of cell cycle progression. Because aberrant regulations of CDK4/cyclin D1 lead to uncontrolled cell proliferation, a hallmark of cancer, small-molecule inhibitors of CDK4/cyclin D1 are attractive as prospective antitumor agents. The series of 4-(phenylaminomethylene)isoquinoline-1,3(2H,4H)-dione derivatives reported here represents a novel class of potent inhibitors that selectively inhibit CDK4 over CDK2 and CDK1 activities. In the headpiece of the 4-(phenylaminomethylene)isoquinoline-1,3(2H,4H)-dione, a basic amine substituent is required on the aniline ring for the CDK4 inhibitory activity. The inhibitory activity is further enhanced when an aryl or heteroaryl substituent is introduced at the C-6 position of the isoquinoline-1,3(2H,4H)-dione core. We present here SAR data and a CDK4 mimic model that explains the binding, potency, and selectivity of our CDK4 selective inhibitors.

From genotype to olfactory neuron phenotype: the role of the Olf-1-binding site

The highly organized pattern of gene expression leading to the determination of cellular phenotype derives from the interplay between genetic and epigenetic factors. This is mediated in part by distinctive DNA sequence motifs present in the regulatory regions of various genes and the transcription factors with which they interact. The phenotype of olfactory neurons is determined in part by the selective expression of novel isoforms of several genes involved in chemosensory transduction. To characterize the mechanisms determining olfactory neuron phenotype we have been studying the olfactory marker protein (OMP), the first olfactory-specific protein to be isolated and cloned. The temporal and spatial expression of OMP is regulated stringently and is highly restricted to mature olfactory neurons in all vertebrates from amphibians to humans. Identification of the specific elements responsible for regulating the expression of the OMP gene will elucidate the mechanisms leading to the determination of olfactory neuron phenotype. Using a combined in vivo (transgenic mice) and in vitro (electrophoretic mobility shift assays and DNase I footprinting) approach, we have identified and characterized a novel genomic motif that binds an olfactory tissue nuclear protein(s) that we designate Olf-1. We propose that Olf-1 is a novel olfactory-specific transacting factor responsible for directing the expression of genes containing the Olf-1 motif in olfactory neurons. Thus it may play a role in regulating the expression of genes associated with neuronal turnover and olfactory transduction.

Validation of cyclin D1/CDK4 as an anticancer drug target in MCF-7 breast cancer cells: Effect of regulated overexpression of cyclin D1 and siRNA-mediated inhibition of endogenous cyclin D1 and CDK4 expression

We have examined the role of cyclin D1 and cyclin-dependent kinase-4 (CDK4) in the cell cycle progression and proliferation of MCF-7 breast cancer cells. Forced expression of cyclin D1 using a tetracycline-regulated expression system, and suppression of endogenous cyclin D1 and CDK4 using small interfering RNA (siRNA) were used to validate this protein complex as a drug target in cancer drug discovery. Overexpression of cyclin D1 increased both phosphorylation of the retinoblastoma gene product (RB) and passage through the G1-S phase transition, resulting in increased proliferation of cells. When cyclin D1 expression was shut off, growth rates fell below those seen in control cell lines transfected with the vector, indicating an increased dependence on this protein for proliferation. Inhibition of endogenous cyclin D1 or CDK4 expression by RNA interference resulted in hypophosphorylation of RB and accumulation of cells in G1. These results support the prevailing view that pharmacological inhibition of cyclin D1/CDK4 complexes is a useful strategy to inhibit the growth of tumors. Furthermore, since MCF-7 cells appear to be dependent on this pathway for their continued proliferation, it is a suitable cell line to test novel cyclin D1/CDK4 inhibitors.

[Complete rectal prolapse in a patient with Hirschsprung disease: a clinical case]

The disease of Mya-Hirschsprung (HD) it's rare and congenital, usually diagnosed in child age, but that it can also remain unknown until the adult age. It's associated to genetic mutations and it can involve other pathologies and malformations. The variability of the anatomopathological and clinical phenomena is correlated to the length of the aganglionic segment. The Authors describe the clinical case of one young female patient, who presented chronic constipation (less than 3 evacuations to week), tenesm, meteorism, abdominal pain. To the inspection of the anal region after the evacuation the presence of complete rectal prolapse (3) cylinders of the length of 30 cm was appraised, with presence of ulcerations of the mucosa. The patient came subordinate to diagnostic study that they demonstrated the presence of HD. The Authors operated the patient with the technique of Frykman and Goldberg. In the follow-up the patient had the complete remission of the symptomatology and resumption of the rectoanal inhibitory reflex, remarkable diminished in the preoperative manometric examination. The pathogenesis of the association of HD and rectal prolapse goes searched in the presence of ultrashort HD (aganglionic defect of a limited segment of rectum), pathological variety somewhat rare that can determine subocclusive phenomena and that it favors the prolapse of the rectum for the continuous evacuating strains.

[The role of surgery in the treatment of adrenocortical carcinoma]

The authors evaluate the role of surgery in the treatment of primary adrenocortical cancer. They describe a case-report of a "giant" surrenalic cancer in a young woman affected by chronic hepatitis B related, submitted to "en bloc" surgical resection, locoregional lumphectomy and omolateral nefropexy. The adjuvant post-operative therapy consisted in six cicles of chemioterapy with Mitotane (op'DDD) at conventional dose. Postoperative course was unevenful and the patient was discharged after four days. Postoperative adjuvant therapy was well tolerated and after one year the patient is disease free. In Italy adrenocortical cancer represents about the 10% of adrenal neoplasms and causes a mortality--cancer related--about of 0.1% among all cancers. The incidence of relapse is about 25% after "en bloc" resection with 5 years survival of 54% in stage I-II, 21.4% in stage III, 6.5% in stage IV, respectively. The age < 40 years a functional activity of the mass, stage and resecability of neoplasm represent the most important prognostic factors. The use of mitotane in the postoperative adjuvant therapy is still controversry with variable results. Surgery represents the treatment of choice in case of primary adrenocortical cancer and is well indicated also for patients with advanced stage and recurrent loco-regional disease.

[Parietal metastasis in laparoscopic surgery of colorectal carcinoma]

The role of videosurgery in the treatment of gastrointestinal cancers is still controversial. However port-site metastases, reported with high rate (0.6-21%) have reduced the enthusiasm and still represent object of research. Port-site metastases pathophysiology is not yet clear. However in the last years the incidence is decreased at a percentage less than 2% and similar to that reported after traditional surgery (0.6-5.3%) due to a patient selection and a better videosurgical technique. Implant for direct contact, pneumoperitoneum, gas utilized, trocar positioning and relative tessutal trauma, visceral manipulation, frequent instrumental reintroduction represent the main pathophysiologic factors involved. Pneumoperitoneum produces an increase of the abdominal pressure with turbulent flows and the CO2 (stimulating of neoplastic cells growth?) transports neoplastic cells at the port site. However metastases occurs only when an elevate cellular concentration is present "gas less" videosurgery is not free from this complication but with a lower incidence. "Chimney effect", due to the leakage of gas or fluid containing aerosol neoplastic cells at port site, represents another important factor. In accord with such studies employing alternative gas (Helium) reduces the implant of neoplastic cells. Port site parietal trauma produces fibrin deposites that represents a substratum for cellular implant, growth and protection against immunitary host defense. Wound ischemia induces a macrophagic activity decrease. In view of these concepts the surgeon must respect some mandatory principles in the videosurgical approach to neoplastic diseases. Safety parietal trocar fixation avoiding gas or fluid port site leakage such as abdominal desuffling only through trocars in site are mandatory. Instrumental cleaning with cytoxic solution (Betadine)--neoplastic cells are isolated from instrumental lavage liquid--such as as irrigation and sterilization (5 FU) of porte site are very important rules. Wound incision--never too small--must be accurately sutured. During operation cutting through or handling tumor are contraindicated, especially when the neoplasm involves serosa. Surgical specimens must be extracted in bags absolutely through parietal protection system. High vascular ligature represents another technical rule to respect in every case like in traditional surgery.

Concealed arrhythmogenic syndromes: the hidden substrate of idiopathic ventricular fibrillation?

In approximately 6--10% of survivors of cardiac arrest no cardiac abnormality can be identified despite extensive clinical evaluation. Autopsy data confirm that in a similar percentage of victims of sudden death no structural heart disease can be identified at post mortem evaluation. Occurrence of cardiac arrest in the absence of a substrate is defined 'idiopathic ventricular fibrillation' thus admitting that the cause for the arrhythmic event has remained unknown. We present data supporting the hypothesis that incompletely penetrant genetic defects may underlie at least some of these unexplained deaths.

Treatment of spit tobacco users with transdermal nicotine system and mint snuff

The purpose of this study was to examine the effects of nicotine patch and mint snuff (a nonnicotine product) on craving, withdrawal symptoms, and treatment outcome. This study involved a 2 x 2 factorial design, with Active Nicotine Versus Placebo Patch as one of the factors and Mint Snuff Versus No Mint Snuff as the other factor. Spit tobacco users (N = 402, n = 100-101 in each condition) were randomly assigned to 1 of the 4 treatment conditions for a period of 10 weeks. Treatment outcome was measured up to 62 weeks. The results showed that the nicotine patch was effective in increasing short-term abstinence over the placebo patch and in reducing craving and withdrawal signs and symptoms from spit tobacco. Although mint snuff was not effective in enhancing treatment outcome, it reduced craving and withdrawal symptoms. No interaction effects were observed. At this time, the use of the nicotine patch and mint snuff should be primarily considered for the reduction of craving and withdrawal symptoms.

Inhibition of ovulation by a novel progestogen (drospirenone) alone or in combination with ethinylestradiol

OBJECTIVE

To investigate ovulation inhibition with drospirenone, a novel progestogen that has a profile similar to natural progesterone, when given alone or in combination with ethinylestradiol.

METHOD

Hormonal parameters (LH, FSH, 17beta-estradiol and progesterone) and peripheral parameters (cervical score, spinnbarkeit and crystallization), as well as follicle size assessed by ultrasonography, were measured in two groups of healthy women. Forty-eight women aged 19-35 years were randomly assigned to receive 0.5 mg, 1.0 mg, 2.0 mg or 3.0 mg of drospirenone over a single treatment cycle, and 52 women aged 20-35 years were randomized to receive either 2 mg drospirenone/30 microg ethinylestradiol or 3 mg drospirenone/30 microg ethinylestradiol over three treatment cycles. Baseline measurements were taken during a control pretreatment cycle.

RESULTS

Adequate ovarian suppression with drospirenone alone was evident at dose levels of 2 and 3 mg, and at 3 mg all subjects had anovulatory cycles. Although both combined preparations (2 mg and 3 mg drospirenone/30 microg ethinylestradiol) inhibited the hypothalamic-pituitary-ovarian axis, follicular maturation leading to escape ovulation was observed in three subjects in the 2 mg drospirenone/30 microg ethinylestradiol group. Only one of these ovulations was considered to be definitely the result of treatment failure. All cycles in the 3 mg drospirenone/30 microg ethinylestradiol group were anovulatory. No statistically significant difference was found between treatment groups.

CONCLUSION

The combination of 3 mg drospirenone/30 microg ethinylestradiol (Yasmin, Schering AG) reliably inhibits ovulation, with a low frequency of follicular maturation, and provides a reasonable safety margin.

Characteristics of smokeless tobacco users seeking treatment

Previous studies have described smokeless tobacco (ST) treatment seekers with minimal detail. In the present study, ST users (N = 402), who enrolled in a ST cessation treatment study, were asked to complete an extensive questionnaire that inquired about their ST use patterns, use of other tobacco products, extent of dependence, previous attempts to quit, situations associated with use and support for quitting. The results showed that this population experiences a high level of nicotine exposure and physical dependence on ST. ST use frequently is associated with negative affect situations and times of hunger. A high frequency of users have smoked cigarettes as well as cigars. A supportive social environment for ST cessation exists for these individuals. These results have implications for ST treatment content.

Compartmental organization of Purkinje cells in the mature and developing mouse cerebellum as revealed by an olfactory marker protein-lacZ transgene

In a line of transgenic mice (HpY-1), the pattern of expression of an olfactory marker protein (OMP)-lacZ fusion gene was analyzed in the cerebellum, where, in adult mice, OMP-lacZ was expressed primarily in Purkinje cells (PCs) of the posterior lobe. The transgene-expressing PCs were organized in parasagittal bands, with a boundary of expression roughly corresponding to the primary fissure that separates the cerebellum into anterior and posterior compartments. The regional expression of the lacZ gene was also analyzed during embryonic and postnatal development of the cerebellum. Within the cerebellum-isthmus region, transgene expression first was detected at embryonic day 13.5 (E13.5) in a cluster of postmitotic cells. By E14.5, lacZ was also expressed by a subpopulation of migrating PCs in the postisthmal and lateral cerebellar primordium, and, by E16.5, transgene-positive PCs formed caudally four sagittal bands symmetric to the medial embryonic fissure. The caudal pattern was retained in postnatal cerebella, where, by postnatal day 0 (P0), transgene-positive PCs in vermal lobules VIII and IX appeared to be organized in two prominent parasagittal compartments on either side of a negative midline band. In early postnatal animals, the transgene was expressed transiently in the anterior lobe vermis. Hence, from P5 onward, transgene expression appeared mostly restricted to the posterior lobe, where it followed a caudal-to-rostral gradient. In the paraflocculus, transgene-expressing PCs were confined to the rostrodorsal portion. The results indicate that the anterior and posterior cerebellar lobes are regulated by distinct ontogenetic programs, and PCs of functionally distinct cerebellar regions express the transgene differentially. Furthermore, the data suggest that ectopic expression of OMP-lacZ in the cerebellum is under the control of regulatory elements that provide positional information for the regional specification of PC subsets.

Effects of mutation of the Olf-1 motif on transgene expression in olfactory receptor neurons

We have examined the effect of mutating the Olf-1 binding motif of the olfactory marker protein (OMP) promoter in determining olfactory neuron-specific gene expression in adult tissues and during embryonic development. The proximal Olf-1 motif located 170 nucleotides upstream of the transcription start site of the OMP gene was mutated to prevent its interaction with the Olf-1 factor in vitro. The wild-type and mutated fragments of the OMP gene extending from -239 to +55 nucleotides relative to the transcription start site were used to direct expression of a lacZ reporter gene in transgenic mice. The transgenic animals were analyzed for cell-specific and developmental expression of the reporter gene. We demonstrate that the mutation that prevents interaction of Olf-1 with its binding site does not alter the temporal and spatial patterns of gene expression in olfactory sensory neurons but does alter the specificity and level of expression in other neuronal populations. These observations are consistent with our demonstration that the mutated Olf-1 site interacts with nuclear proteins present in the central nervous system (CNS).

NMR spectroscopy and MRI investigation of a potential bioartificial liver

NMR feasibility was established for a coaxial hydrophobic-membrane bioreactor containing isolated rat hepatocytes with features designed to mimic the human liver. A novel triple-tuned NMR probe and a perfusion system controlling temperature, gas concentrations, flow-rate, and pH were used. We determined the optimum coaxial interfiber distance (i.e. diffusion distance) for maintaining hepatocyte viability in two bioreactor prototypes. Prototype no. 1 and no. 2 had diffusion distances of 500 microns and 200 microns, respectively. Cell viability was established by 31P NMR and trypan blue exclusion. Only prototype no. 2 maintained cell viability for more than 6 h, indicating the importance of diffusion distance. 31P spectra obtained over this 6 h time period were similar to in vivo spectra of rat liver. The 31P spectra were found to be more sensitive to subacute cell viability than trypan blue exclusion. In the 1H and 31P spectra, 1H2O and inorganic phosphate signals were split in two at all flow-rates, probably due to bulk magnetic susceptibility effects originating from the three bioreactor compartments. MRI was useful for quality control and determining flow dynamics, fiber integrity, and cell inoculate distribution. MRI revealed that the inner fibers were not centered in either prototype. Although an increased flow-rate did not influence spectral resolution or chemical shifts, significant degradation of MRI quality occurred above 50 mL/min. NMR spectroscopy and imaging provide valuable, real-time information on cell biochemistry and flow dynamics which can be used in development and monitoring of bioreactors designed as artificial livers.

Safety of cotinine in humans: physiologic, subjective, and cognitive effects

Preliminary data suggest that cotinine, the major metabolite of nicotine, may be behaviorally active. Studies involving the administration of cotinine at doses that produce high blood concentrations (in excess of those produced by cigarette smoking) may be of interest. This inpatient, 10-day human study examined the safety and the effects from several high doses of oral cotinine fumarate (40, 80, or 160 mg) or placebo in abstinent cigarette smokers. All subjects smoked cigarettes ad lib during the first 2 days of the study, then were required to be abstinent beginning on the third day. All subjects were given placebo on this day to wash out nicotine before the administration of cotinine. Subjects were subsequently randomly assigned in a double-blind manner to cotinine or placebo for the next 3 days to determine the safety profile of cotinine. All subjects were given placebo on the final 3 days to examine cotinine withdrawal symptoms. The results showed no significant physiologic, subjective, or performance effects across the various doses of cotinine and placebo. Furthermore, no cotinine withdrawal effects were observed. This study demonstrates that short-term administration of cotinine to humans at levels as high as 10 times that attained from cigarette smoking is safe with no observable acute or withdrawal effects from cotinine in this setting.

Effects of behavioral and pharmacological treatment on smokeless tobacco users

The purpose of this study was to examine the effects of 2 mg of nicotine polacrilex versus placebo gum and of group behavioral treatment versus minimal contact on cessation of smokeless tobacco use. Participants (N = 210) were randomly assigned 1 of the 4 treatment conditions. Withdrawal symptoms were assessed throughout the treatment. Follow-up assessments were made at 1, 6, and 12 months posttreatment. Survival curve analysis showed that any of the 3 treatment groups involving group behavioral therapy or placebo gum were equally effective and superior to the minimal contact plus 2 mg of nicotine gum treatment in terms of abstinence. On the other hand, withdrawal symptoms were significantly reduced by nicotine gum, compared with placebo during the initial phases of cessation. The ineffectiveness of nicotine gum on treatment outcome may be attributed to its similarity with smokeless tobacco.

LacZ and OMP are co-expressed during ontogeny and regeneration in olfactory receptor neurons of OMP promoter-lacZ transgenic mice

The ontogeny and cellular specificity of expression of beta-galactosidase activity and olfactory marker protein (OMP) are compared in olfactory tissue of the H-OMP-lacZ-3 line of transgenic mice. In this line the expression of lacZ is driven by a 0.3 kb fragment of the rat OMP promoter. During fetal development, lacZ expression is detectable in olfactory receptor neurons (ORNs) shortly after the initial appearance of endogenous OMP. The beta-galactosidase marker was observed only in mature olfactory receptor neurons where it co-localized with endogenous OMP. It was absent from immature neurons that express the growth associated phosphoprotein B50/GAP43. Lesion of the peripheral olfactory pathway by intranasal irrigation with Triton X-100 eliminated expression of both OMP and lacZ in the olfactory neuroepithelium. Subsequent regeneration of the full complement of olfactory receptor neurons was associated with co-expression of both OMP and beta-galactosidase activity. Neither OMP nor beta-galactosidase activity was induced in any other cell type of the regenerating olfactory mucosa. Thus, as little as 0.3 kb of the OMP promoter has the ability to target lacZ expression to olfactory receptor neurons in a temporally and spatially defined manner. We discuss the potential utility of this transgenic line for future studies of the olfactory system.

Olfactory marker protein (OMP) gene deletion causes altered physiological activity of olfactory sensory neurons

Olfactory marker protein (OMP) is an abundant, phylogentically conserved, cytoplasmic protein of unknown function expressed almost exclusively in mature olfactory sensory neurons. To address its function, we generated OMP-deficient mice by gene targeting in embryonic stem cells. We report that these OMP-null mice are compromised in their ability to respond to odor stimull, providing insight to OMP function. The maximal electroolfactogram response of the olfactory neuroepithelium to several odorants was 20-40% smaller in the mutants compared with controls. In addition, the onset and recovery kinetics following isoamyl acetate stimulation are prolonged in the null mice. Furthermore, the ability of the mutants to respond to the second odor pulse of a pair is impaired, over a range of concentrations, compared with controls. These results imply that neural activity directed toward the olfactory bulb is also reduced. The bulbar phenotype observed in the OMP-null mouse is consistent with this hypothesis. Bulbar activity of tyrosine hydroxylase, the rate limiting enzyme of catecholamine biosynthesis, and content of the neuropeptide cholecystokinin are reduced by 65% and 50%, respectively. This similarity to postsynaptic changes in gene expression induced by peripheral olfactory deafferentation or naris blockade confirms that functional neural activity is reduced in both the olfactory neuroepithelium and the olfactory nerve projection to the bulb in the OMP-null mouse. These observations provide strong support for the conclusion that OMP is a novel modulatory component of the odor detection/signal transduction cascade.

Effects of behavioral and pharmacological treatment on smokeless tobacco users

The purpose of this study was to examine the effects of 2 mg of nicotine polacrilex versus placebo gum and of group behavioral treatment versus minimal contact on cessation of smokeless tobacco use. Participants (N = 210) were randomly assigned 1 of the 4 treatment conditions. Withdrawal symptoms were assessed throughout the treatment. Follow-up assessments were made at 1, 6, and 12 months posttreatment. Survival curve analysis showed that any of the 3 treatment groups involving group behavioral therapy or placebo gum were equally effective and superior to the minimal contact plus 2 mg of nicotine gum treatment in terms of abstinence. On the other hand, withdrawal symptoms were significantly reduced by nicotine gum, compared with placebo during the initial phases of cessation. The ineffectiveness of nicotine gum on treatment outcome may be attributed to its similarity with smokeless tobacco.

Proximal regions of the olfactory marker protein gene promoter direct olfactory neuron-specific expression in transgenic mice

Olfactory marker protein (OMP) expression is highly restricted to mature olfactory neurons (ON). Less than 0.3 kb of upstream 5' flanking sequence of the OMP gene directs lacZ expression preferentially to ON in several independently derived lines of transgenic mice. A larger transgene with 0.8 kb of upstream flanking sequence also gave lacZ expression in ON and in a few ectopic sites in the central nervous system (CNS). In addition to the main olfactory epithelium, endogenous OMP is also expressed in chemosensory neurons of the vomeronasal and septal organs, and lacZ expression was detected in neurons of these sites as well. This confirmed the presence of regulatory sequences in the proximal portion of the OMP gene. Endogenous OMP expression in ON was normal in all transgenic lines. Strikingly, in several transgenic lines lacZ expression was restricted to subsets of ON. In one such line, ON axons were intensely stained for lacZ and projected to a subset of olfactory bulb glomeruli. Although identifiable subsets of ON and their termination fields have been described previously, this is the first demonstration of this phenomenon in transgenic mice. These lines of transgenic mice thus provide in vivo models for characterization of genetic elements regulating developmental and functional organization of the olfactory neuroepithelium.

Effects of treatment on cardiovascular risk among smokeless tobacco users

BACKGROUND

Studies show sustained levels of nicotine among young males using smokeless tobacco, causing concern for subsequent cardiovascular risk. Also, there is little information on effects of nicotine replacement on cardiovascular risk in cessation programs. This study investigates the effects of nicotine gum replacement in smokeless tobacco cessation on cardiovascular risk factors.

METHODS

Smokeless tobacco users, ages 18-65, were randomly assigned in a double-blind fashion to 2-mg nicotine or placebo gum. At baseline, Week 4, and Week 8, dependent measurements, heart rate, blood pressure, and weight were recorded, and fasting lipoprotein profiles were drawn.

RESULTS

This paper focuses on the smokeless tobacco users who refrained from use during the study period (N = 56). The nicotine gum group weighed less (P = 0.033) than the placebo group throughout the study and weight increased at a significant rate between Weeks 4 and 8 for both groups as gum decreased. Triglycerides were higher for the nicotine gum group than the placebo group (P = 0.031), with triglycerides decreasing between Weeks 4 and 8, with a similar effect seen among nonabstinent smokeless tobacco users. There was no dose, time, or dose by time effect for the other dependent measures.

CONCLUSIONS

Among smokeless tobacco users who were abstinent, weight increased, with subjects on nicotine gum weighing less throughout the study. The lipoprotein profile, heart rate, and blood pressure did not improve over time, contrary to smokers in whom HDL increases and heart rate decreases with cessation. This could relate to different routes of administration, pharmacokinetics, or by-products of tobacco smoking being absent in smokeless tobacco. In addition, nicotine gum appeared to have neither an adverse nor a positive effect on heart rate, blood pressure, LDL, HDL, or total cholesterol.

[Combination of Cantrell pentalogy and amniotic band syndrome: a case report]

A case is reported of sonographic diagnosis of ADAM-complex (amniotic band syndrome) in combination with Cantrell-syndrome in the 19th gestational week. The ultrasonic investigation also showed a large defect in the fetal skull with encepholocele as well as a marked defect of the abdominal wall and chest with dislocation of the intestines, liver, and heart. The pregnancy was interrupted because of the severe fetal malformations. Aetiology and pathogenesis of such rare abnormalities and possible correlations between ADAM-syndrome and Cantrell-syndrome are discussed with reference to the literature.

Olf-1-binding site: characterization of an olfactory neuron-specific promoter motif

We report characterization of several domains within the 5' flanking region of the olfactory marker protein (OMP) gene that may participate in regulating transcription of this and other olfactory neuron-specific genes. Analysis by electrophoretic mobility shift assay and DNase I footprinting identifies two regions that contain a novel sequence motif. Interactions between this motif and nuclear proteins were detected only with nuclear protein extracts derived from olfactory neuroepithelium, and this activity is more abundant in olfactory epithelium enriched in immature neurons. We have designated a factor(s) involved in this binding as Olf-1. The Olf-1-binding motif consensus sequence was defined as TCCCC(A/T)NGGAG. Studies with transgenic mice indicate that a 0.3-kb fragment of the OMP gene containing one Olf-1 motif is sufficient for olfactory tissue-specific expression of the reporter gene. Some of the other identified sequence motifs also interact specifically with olfactory nuclear protein extracts. We propose that Olf-1 is a novel, olfactory neuron-specific trans-acting factor involved in the cell-specific expression of OMP.

[Development of symptoms and perinatal complications in HELLP syndrome]

At the Kiel University Department of Gynaecology, 21 patients between the 21th and 39th week of gestation were treated in 1987 and 1988 following diagnosis of HELLP syndrome. At the time of diagnosis all patients presented an advanced gestosis/eclampsia. 9 patients developed the classical signs and symptoms, while hospitalised. The typical signs of gestosis, hypertension, proteinurea, oedema and hypoproteinaemia preceded the changes in laboratory values caused by the HELLP syndrome. Upper abdominal pain and increase in transaminase values occurred on the average 3.4 or 2.7 days prior to the decrease of, thrombocyte count. In 19 of the 21 cases, pregnancy was terminated by caesarean section. Severe peripartal complications occurred in 7 cases e.g. foetal death in utero (n = 3), eclampsia (n = 5), renal failure (n = 2), cerebral oedema (n = 1), intracerebral haemorrhage (n = 1), disseminated intravascular coagulation (n = 1), abdominal wall haematoma (n = 1). 6 of these patients were admitted after complications had occurred prior to admittance. All 18 infants born alive survived the neonatal period. The average birth weight was 1,571 g. 11 infants were discharged clinically normal. The remaining infants included 5 cases pointing to retinopathy and 3 cases of cerebral palsy. One infant developed post-haemorrhagic hydrocephalus.

Vomeromodulin, a putative pheromone transporter: cloning, characterization, and cellular localization of a novel glycoprotein of lateral nasal gland

Vomeromodulin, a novel glycoprotein of lateral nasal gland, has been cloned by differential hybridization from nasal/olfactory tissue. The 2.2-kb mRNA directs the in vitro synthesis of a 60-kDa primary translation product in reticulocyte lysates. Differential sensitivity to endoglycosidases indicates that vomeromodulin is posttranslationally modified in vivo by N-glycosylation to form a 70-kDa glycoprotein of the complex type. Immunocytochemical localization with two different antipeptide antisera demonstrates that vomeromodulin is abundant in the lateral nasal glands and is also present in the posterior septal and vomeronasal glands. Most striking is the observation that it is highly concentrated in the mucus of the vomeronasal organ of Jacobson but is not detectable in the mucus of the main olfactory neuroepithelium. Evaluation of mRNA and protein distribution by Northern and Western analyses, respectively, indicates that vomeromodulin is absent from 15 other tissues. The glandular and mucosal distribution of this glycoprotein implies a transport function that may be related to the mechanisms by which pheromones of low volatility gain access to their receptors in the vomeronasal organ. These observations support our hypothesis that vomeromodulin participates in perireceptor events that facilitate the process of pheromone access and detection.

Differential effect of functional olfactory bulb deafferentation on tyrosine hydroxylase and glutamic acid decarboxylase messenger RNA levels in rodent juxtaglomerular neurons

Expression of the dopaminergic phenotype in olfactory bulb (OB) juxtaglomerular neurons (constituting a population of periglomerular and external tufted cells) is dependent upon functional innervation by peripheral olfactory receptors. Loss of functional input in rodents, by either peripheral deafferentation or deprivation of odorant access, results in a profound decrease in the expression of juxtaglomerular tyrosine hydroxylase (TH). We have examined the effects of such treatments on the expression of the neurotransmitter biosynthetic enzyme glutamic acid decarboxylase (GAD), which is colocalized with TH in the majority of TH-containing juxtaglomerular neurons. Following either chemically induced OB deafferentation in adult mice or unilateral odor deprivation in neonatal rats, steady-state OB GAD messenger RNA levels remained essentially unchanged as assessed by Northern blot analysis 20-40 days after treatment. These results were confirmed by in situ hybridization analysis, which demonstrated a profound loss of juxtaglomerular TH messenger RNA but no accompanying decrease in regionally colocalized GAD message. Since GAD is found in nearly all dopaminergic OB cells, the preservation of juxtaglomerular GAD message implies that olfactory receptor neurons exert a differential transneuronal regulation of TH and GAD gene transcription.

Regulation of gene expression in the olfactory neuroepithelium: a neurogenetic matrix

The olfactory neuroepithelium exhibits neurogenesis throughout adult life, and in response to lesions, a phenomenon that distinguishes this neural tissue from the rest of the mammalian brain. The newly formed primary olfactory neurons elaborate axons into the olfactory bulb. Thus, denervation and subsequent reinnervation of olfactory bulb neurons may occur throughout life. This unique ability of the olfactory neuroepithelium to generate new neurons from a population of precursor cells present in the basal cell layer of this tissue makes it a valuable model in the study of neural development and regeneration. The molecular processes underlying the neurogenic properties of the olfactory neuroepithelium are poorly understood. Here we have reviewed our studies on the expression of B50/GAP43 during ontogeny of the olfactory system and following lesioning. This analysis includes the characterization of the expression of OMP, a protein expressed in mature olfactory neurons, as well as PKC and calmodulin. The latter two molecules are of particular interest to the function of B50/GAP43 since the degree of phosphorylation of B50/GAP43 appears to determine B50/GAP43's ability to bind calmodulin (see also Storm, chapter 4, this volume). In the mature olfactory epithelium B50/GAP43 expression is restricted to a subset of cells located in the basal region. Since the expression of B50/GAP43 is high in developing and regenerating nerve cells we are confident that the B50/GAP43 positive cells are new neurons derived from the stem cells in the basal region of the epithelium. B50/GAP43 is absent from the stem cells themselves and also from the mature OMP-expressing neurons. On the basis of the patterns of B50/GAP43 and OMP expression two stages could be discriminated in the regeneration of the olfactory epithelium. First, as an immediate response to lesioning a large population of B50/GAP43 positive, OMP negative neurons are formed. Subsequently, during the second stage, these newly formed differentiating neurons mature as evidenced by a decrease in B50/GAP43 and an increase in OMP expression. The second stage in the regeneration process is only manifested if the regenerating neurons can reach their target cells in the olfactory bulb. Hence, bulbectomy results in the arrest of the reconstituted olfactory epithelium in an immature state. The differential patterns of B50/GAP43 expression following peripheral lesioning and bulbectomy suggest the existence of a target derived signal molecule involved in the down-regulation of B50/GAP43 expression in olfactory neurons that have established synaptic contacts in the olfactory bulb (see also Willard, chapter 2, this volume, "the suppressor hypothesis").(ABSTRACT TRUNCATED AT 400 WORDS)

Use of reverse transcriptase polymerase chain reaction to monitor expression of intronless genes

Our data demonstrate the use of the reverse transcriptase polymerase chain reaction (RT-PCR) technique to study mRNA expression of genes that are devoid of introns. We have developed conditions that eliminate the false positives that can result from any preexisting DNA and that could confuse the interpretation of results. This modification (DNase pretreatment under specified conditions) ensures that the product resulting from RT-PCR is due to amplification of cDNA that has been synthesized during the reverse transcriptase reaction. Our results illustrate and emphasize the importance of including both a DNase pretreatment and a minus RT control. Using this modified procedure, our data illustrate clearly the ability of this protocol to demonstrate the presence of very low levels of olfactory marker protein (OMP) mRNA in three non-olfactory rat brain regions (cerebellum, thalamus/hypothalamus and cerebral hemispheres) where OMP mRNA was previously unknown. These data confirm a prior report of the ectopic expression of OMP immunoreactivity in these locations and indicate for the first time the "illegitimate" expression of extremely low levels of OMP mRNA in a non-neural tissue. Finally, this modification of the RT-PCR procedure will now permit the study of expression of specific, rare, mRNA molecules in the absence of any prior knowledge of the structure of their genes of origin.

Neuroplasticity in the olfactory system: differential effects of central and peripheral lesions of the primary olfactory pathway on the expression of B-50/GAP43 and the olfactory marker protein

The regeneration of the olfactory neuroepithelium following olfactory bulbectomy or peripheral deafferentation was studied with mRNA probes and antibodies for B-50/GAP43 and for olfactory marker protein (OMP). Two stages in the regeneration of the olfactory epithelium could be discerned with these reagents. The first stage occurs following either peripheral deafferentation of the olfactory epithelium with Triton X-100 (TX-100) or after bulbectomy and is characterized by the formation of a large population of immature olfactory receptor neurons. These newly formed neurons express B-50/GAP43, a phosphoprotein related to neuronal growth and plasticity. During the second stage of the regeneration process the newly formed olfactory neurons mature, as evidenced by a decrease in their expression of B-50/GAP43 and an increase in the expression of OMP. This stage is only manifested if the developing neurons have access to the target olfactory bulb. Formation of a full complement of OMP-expressing neurons occurs only after peripheral lesion with TX-100. In contrast, following bulbectomy the reconstituted olfactory epithelium lacks its normal target and is compromised in its ability to recover from nerve damage, as evidenced by the presence of a large number of B-50/GAP43-expressing neurons up to 3 months after the lesion and its failure to establish a full complement of OMP-expressing neurons. These results demonstrate that the olfactory epithelium is capable of replacing its sensory neurons independently of the presence of its target, the olfactory bulb. However, the differential patterns of expression of B-50/GAP43 and OMP at long times after peripheral lesion with TX-100 or bulbectomy illustrate the profound effect the olfactory bulb has on neuronal maturation in reconstituted olfactory neuroepithelium.

Expression of catfish amino acid taste receptors in Xenopus oocytes

We demonstrate that poly (A+)RNA isolated from catfish barbels directs the expression of functional amino acid taste receptors in the Xenopus oocyte. The activity of these receptors is monitored in ovo by the two electrode voltage clamp technique. Specific conductance changes recorded in response to amino acid stimulation are analogous to those recorded electrophysiologically from intact catfish barbels. These responses exhibit specificity, reproducibility, rapid onset and termination, and desensitization to repetitive stimulation. A functional assay system that encompasses the full complement of transduction events from the ligand-receptor interaction to subsequent conductance changes is necessary to identify molecular components responsible for these events. Our results demonstrate that the Xenopus oocyte can be used to characterize and identify clones coding for amino acid taste receptors analogous to its use in studying receptor molecules for other neuroactive compounds.

Transneuronal regulation of neuronal specific gene expression in the mouse olfactory bulb

Peripheral afferent denervation (deafferentation) of the rodent main olfactory bulb produces a marked decrease in tyrosine hydroxylase (TH) activity and immunoreactivity in a population of juxtaglomerular dopaminergic neurons. Preservation of activity and immunostaining for aromatic L-amino acid decarboxylase implies that these cells do not die, but change phenotype. We now report that the steady-state level of TH mRNA markedly decreases in the adult mouse olfactory bulb in response to deafferentation. This reduction is permanent following intranasal irrigation with 0.17 M zinc sulphate (ZnSO4) but reversible following deafferentation produced by intranasal irrigation with 0.7% Triton X-100. The initial declines in TH activity, protein and mRNA of dopaminergic juxtaglomerular neurons observed after Triton X-100 treatment are all reversible as the steady-state level of TH mRNA gradually returns to control levels. Steady-state levels of mRNA for olfactory marker protein (OMP), a protein found in high concentrations in olfactory receptor neurons and their processes which innervate the olfactory bulb, were also monitored following deafferentation. Following treatment with either ZnSO4 or Triton X-100, the pattern of changes in steady-state levels of OMP mRNA was similar to that observed for TH. The steady-state level of PEP19 mRNA, a peptide previously localized to granule cells in the olfactory bulb, was not altered by deafferentation. These data indicate selective and parallel regulation of TH and OMP message and protein levels following deafferentation.

Cellular localization of carnosine-like and anserine-like immunoreactivities in rodent and avian central nervous system

Aminoacylhistidine dipeptides are present in the nervous tissue of many species. The olfactory mucosa and bulb of many vertebrates are rich in carnosine (beta-alanyl-L-histidine). Two related dipeptides homocarnosine (gamma-aminobutyryl-L-histidine) and anserine (beta-alanyl-N-methyl-L-histidine) are present in the CNS of mammals and birds, respectively. This manuscript describes the production, characterization and use in immunolocalization studies of antisera directed against carnosine and anserine. The anserine antiserum is highly specific for anserine while the carnosine antiserum cross-reacts with all three dipeptides. The differential specificity of the antisera, coupled with chemical characterization of the dipeptide composition of various brain regions, has permitted assignment of the cellular localization of the various dipeptides. Immunocytochemical localization of anserine has not been previously reported. Carnosine immunoreactivity in the olfactory system is restricted to the mature neurons in the olfactory mucosa, their axons and synaptic terminations in the glomerular layer of the olfactory bulb. Similar reactivity is seen in the accessory olfactory system. Astrocytes and cerebellar Bergmann glia seem to account for all the non-olfactory carnosine-like immunoreactive staining in the rodent brain. In contrast, in the avian CNS where anserine is chemically abundant, anserine-like immunoreactivity is widespread and apparently exclusively associated with glial cells. Thus, the olfactory receptor neurons appear to be the only neuronal population that expresses carnosine. Elsewhere in the CNS the aminoacylhistidine dipeptides are associated with various populations of glia.

[Sonographic diagnosis of amniotic band syndrome]

A case is reported of sonographic diagnosis of ADAM-complex (amniotic band syndrome) in the 19th week of gestation of an otherwise healthy pregnancy. The ultrasonic investigation showed absence of bony structures in the skull area a direct connection to the placenta. The intra-cerebral structures showed no abnormalities. Aminocentesis demonstrated normal chromosomal analysis and an alpha-fetoprotein value was within normal limits. The acetylcholinesterase examination was negative. Following prostaglandin induction, a spontaneous delivery of a 230 g freshly dead fetus occurred, the latter exhibiting a broadly-based amniotic band connection between skull and placenta.

Minimal andrological requirements for in-vitro fertilization

The ejaculate used for in-vitro fertilization of human oocytes must fulfil minimum requirements. Based on the results of experimental investigations, total concentrations of spermatozoa must be greater than 5 million spermatozoa/microliters with progressive motilities of at least 30% and also a normal morphology of at least 30%. Furthermore, in sperm preparations used for inseminating human oocytes, the concentration of pathogenic microorganisms must not be less than 10(4). If there are positive bacteriological findings, the treatment of both partners is mandatory according to the antibiogram. According to the information gathered to date, the hamster oocyte penetration test can only provide additional information if it is positive, but acceptance into an IVF programme should not depend on this test. According to the results presented so far, the swell test developed by Jeyendran shows quite good correlation with the fertilization of human oocytes.

Biochemical and immunocytochemical characterization of olfactory marker protein in the rodent central nervous system

Olfactory marker protein (OMP), previously thought to be expressed only by olfactory receptor neurons and their processes, was localized anatomically with immunocytochemical techniques to a number of brain regions in three rodent species, the mouse, rat, and hamster. In addition, the amount of antigen was quantified by radioimmunoassay (RIA) and characterized by an immunoblot procedure. In all three species the antigen could be detected immunocytochemically in the preoptic region and hypothalamus. The rat did not exhibit immunostaining in any other brain region. However, in the mouse neuronal labelling was observed throughout the neural axis, including cellular labelling in the bed nucleus of the anterior commissure, the median preoptic nucleus, the bed nucleus of the stria terminalis, the periventricular region, the anterior parvicellular subnucleus of the paraventricular nucleus, around the dorsomedial hypothalamic nucleus (pars compacta), the subincertal region, the arcuate nucleus, the anterior cortical nucleus of the amygdala, the suprageniculate nucleus, the lateral lemniscal nuclei, the lateraldorsal and lateralventral central gray, the posterior aspects of the commissural and marginal nuclei of the inferior colliculus, the paragenule nucleus, the A-5 region, the area postrema, the ventromedial nucleus of the solitary tract, area X, the spinal trigeminal nucleus (pars zonale), and superficial laminae of the spinal cord. The hamster displayed a different pattern of labelling including cells in the periventricular gray, the pontine reticular tegmental nucleus, the A-5 region, the medial vestibular complex, the prepositus hypoglossal nucleus, the parvicellular reticular nucleus, the lateral paragigantocellular nucleus, the raphe obscuras, the lateral reticular nucleus, and the lateral nucleus of the cerebellum. Immunostaining was seen in fibers within the red nucleus and within mossy fibers of the cerebellum. OMP levels could only be quantified by radioimmunoassay in the olfactory bulb of the three species and in the hamster cerebellum where they were 1/1,000 of those determined in the olfactory bulb. The authenticity of OMP measured in the RIA and detected immunocytochemically was verified by a double-antibody immunoisolation/immunodetection procedure, which confirmed that the antigen being visualized had the molecular properties expected for OMP. In summary, these experiments demonstrate that authentic OMP exists in small groups of neurons in many areas of the central nervous system.