Stool antigen testing for the diagnosis and confirmation of eradication of Helicobacter pylori infection.
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Adult↗
Biomedical subjects
R A Wallace
Publications and source records attributed to R A Wallace.
Effects of Helicobacter pylori eradication among adults with intellectual disability.
BACKGROUND: Compared to the general population, Helicobacter pylori infection is more common among adults with intellectual disability (ID) and is associated with greater levels of disability, maladaptive behaviour, and institutionalization. Little information exists about the effects of eradication therapy in this group, so we aimed to evaluate: (1) success of a standard H. pylori eradication protocol; (2) frequency of side-effects; and (3) impact of eradication on level of functional ability and maladaptive behaviour. METHOD: A cohort of adults with ID underwent assessment of their levels of function and maladaptive behaviour, medical history, physical examination, and H. pylori testing using serology and faecal antigen tests. Some received standard H. pylori eradication therapy. Twelve months later, participants underwent repeat assessment, were grouped by change in H. pylori status and compared. RESULTS: Of 168 participants, 117 (70%) were currently infected with H. pylori at baseline, and 96 (82%) of the 117 were given standard H. pylori eradication therapy. The overall eradication rate was 61% but 31% reported side-effects. Institutional status of the participants, their level of behaviour or function, and number of comorbid medical conditions were not associated with failure of eradication. There were no statistically significant differences in level of behaviour or function, ferritin, or weight between the groups in whom H. pylori was eradicated or stayed positive. CONCLUSION: Adults with ID have lower H. pylori eradication and higher side-effect rates than the general population. Levels of maladaptive behaviour and disability did not improve with eradication and thus greater levels of maladaptive behaviour or disability appear to be risk factors for, rather than consequences of, H. pylori infection.
Adult↗
Recurrence of Helicobacter pylori infection in adults with intellectual disability.
Although Helicobacter pylori infection is very common among particular groups of adults with intellectual disability, the rate of recurrence (reinfection or recrudescence) is unknown in this population. Thirty-six months after successful treatment of H. pylori, 28 adults with intellectual disability were retested using the faecal antigen test. Six (21%) of 28 patients tested positive, giving an approximate yearly recurrence rate of 7%, a rate considerably higher than that in the general population (<1%). It is recommended that adults with intellectual disability who have had successful treatment of H. pylori be retested for an interval of 3-5 years after treatment.
Adult↗
Synchronization of estrus in postpartum beef cows and virgin heifers using combinations of melengestrol acetate, GnRH, and PGF2alpha.
The efficacy of various combinations of melengestrol acetate (MGA), GnRH, and PGF2alpha for the synchronization of estrus in Angus-based beef cattle was compared. Hormones were administered as follows: MGA, 0.5 mg x animal(-1) x d(-1) mixed in a grain carrier; GnRH, 100 microg i.m.; PGF2alpha, 25 mg i.m. In Exp. 1, 2, and 3, cows were randomly assigned to treatments by parity and interval postpartum. The detection of estrus and AI were conducted from d -2 until 72 to 96 h after PGF2alpha, at which time cows not detected to be in estrus received GnRH and fixed-time AI (TAI). Data were analyzed separately for primiparous and multiparous cows. In Exp. 1, cows (n = 799) at three locations received GnRH on d -7 and PGF2alpha on d 0 and either no further treatment (GnRH-PGF) or short-term MGA from d -6 through d -1 (STMGA). Among multiparous cows, conception rate at TAI was greater (P < 0.05) for STMGA (41%, 47/115) than for GnRH-PGF treated cows (26%, 24/92). Across herds and parity, synchronized AI pregnancy rate (SPR) was not affected (P > 0.10) by treatment (GnRH-PGF vs. STMGA; 54%, 210/389 vs. 57%, 228/402). In Exp. 2, cows (n = 484) at three locations received either STMGA or long-term MGA from d -32 through d -19, GnRH on d -7, and PGF2alpha on d 0 (LTMGA). Among primiparous cows, SPR was greater (P < 0.01) in LTMGA (65%, 55/85) than STMGA-treated cows (46%, 40/87). Treatment had no effect (P > 0.10) on SPR among multiparous cows (STMGA vs. LTMGA; 59%, 92/155 vs. 64%, 101/157). In Exp. 3, cows (n = 838) at four locations received the LTMGA treatment and either no further treatment or an additional period of MGA exposure from d -6 through d -1 (L&STMGA). Among primiparous cows, SPR tended to be influenced (P < 0.10) by the herd x treatment interaction and was greater (P < 0.01) among L&STMGA (86%, 19/22) than LTMGA-treated cows (56%, 14/25) at a single location. Among multiparous cows, SPR was lower (P < 0.05) in L&STMGA (46%, 165/358) than LTMGA-treated cows (55%, 184/336). In Exp. 4, Angus heifers (n = 155) received either STMGA or 14 d of MGA (d -32 through d -19) and PGF2alpha on d 0 (MGA-PGF). The detection of estrus and AI were conducted from d -2 to d 6. Interval to estrus was greater (P < 0.05) and estrous response was lower (P < 0.05) in STMGA than MGA-PGF-treated heifers. In conclusion, primiparous cows responded more favorably to longer-duration MGA treatments than did multiparous cows. All protocols achieved sufficient SPR to justify their use for improved reproductive management of postpartum beef cows.
Animals↗
Synchronization of estrus in virgin beef heifers using melengestrol acetate and PGF2alpha: an efficacy comparison of cloprostenol and dinoprost tromethamine.
This study compared the efficacy of two sources of PGF2alpha on the reproductive performance of virgin beef heifers, after synchronization of estrus using melengestrol acetate (MGA) and PGF2alpha. Angus-based heifers (n = 1002) in five herds were fed 0.5 mg per head per day of MGA for 14 days. Nineteen days after the last day of MGA feeding, heifers were randomly assigned to receive (i.m.) either 0.5 mg cloprostenol (n = 504; Estrumate, E) or 25 mg dinoprost tromethamine (n = 498; Lutalyse, L) as a source of exogenous PGF2alpha. Heifers were observed twice daily for 5 days for signs of estrus and artificially inseminated 8-12 h later, except in herd A, wherein animals not detected in estrus by 80 h after PGF2alpha were mass-mated and no longer monitored for signs of estrus. Estrumate and Lutalyse were equally (P > 0.1) effective among all response variables evaluated, including estrus response (E, 89% and L, 86%), conception rate (E, 67% and L, 67%), and synchronized pregnancy rate (E, 61% and L, 57%). Synchrony of estrus was not affected (P > 0.1) by PGF2alpha source, and peak estrus response occurred 60 h post-PGF for both treatments. Conception rate to timed insemination was not different (P > 0.1) among Estrumate- and Lutalyse-treated heifers within herd A (14%, 4/28 and 7%, 2/29, respectively). Herd had a significant (P < 0.05) effect on all indicators of reproductive performance. Conception rates within herds A and D were influenced by technician (P < 0.05), however, this effect was balanced across treatments and no treatment by technician interaction was detected. In conclusion, when administered 19 days after a 14-day MGA feeding period, cloprostenol and dinoprost tromethamine are equally efficacious for synchronous induction of a fertile estrus in virgin beef heifers.
Animals↗
Environmental, medical, behavioural and disability factors associated with Helicobacter pylori infection in adults with intellectual disability.
In institutionalized adults with intellectual disability (ID), Helicobacter pylori infection occurs at approximately twice the rate it appears in the general population, and it may be responsible for the twofold higher rates of peptic ulcer disease and gastric cancer in this population. Medical, behavioural and additional environmental factors, as well as level of ID, may be related to the risk of infection with H. pylori. One hundred and sixty-eight adults with ID who were currently, had previously been or had never been institutionalized underwent a biopsychosocial evaluation. This included assessment of: level of ID using the Adaptive Behaviour Scale (ABS) Part I; levels of maladaptive behaviour using the ABS Part II; demographic, medical and environmental factors; as well as H. pylori tests using serology and faecal antigen. The overall rates of past or current infection with H. pylori in institutionalized and previously institutionalized participants were about twice that of the overall group of never-institutionalized participants, i.e. 87% and 79% compared to 44%, respectively (P < 0.001). The rates of H. pylori infection appeared to increase with age in the never-institutionalized group, but were consistently high across all ages in the other groups. The rate of infection was higher in those institutionalized for more than 5 years (95% versus 76%, P=0.02), in those with flatmates with excessive oral secretions (65% versus 21%, P < 0.001) or faecal incontinence (67% versus 27%, P < 0.001), and in those with more chronic illness and medications. All mean domain scores of the ABS Part I (Intellectual Disability) were significantly lower (indicating more severe ID) in the group currently infected with H. pylori compared to their non-infected counterparts. The majority of mean domain scores of the ABS Part II (Behaviour) were also worse, with half of these score differences reaching statistical significance in the currently infected group. The presence of alarm symptoms (e.g. vomiting, weight loss, haematemesis and melena), iron deficiency and body mass index were not significantly different in currently infected subjects. Adults with ID appear to be particularly at risk of infection with H. pylori. Environmental associations with infection include past or current institutionalization, a longer period of institutionalization, living with flatmates with excessive oral secretions and faecal incontinence. Medical associations include chronic disease and more medications, but not alarm symptoms or body mass index. Demographic associations may include increasing age in never-institutionalized adults, but no age effect in currently or previously institutionalized individuals. Psychosocial associations include more severe ID and maladaptive behaviour with current infection.
Adaptation, Psychological↗
Bafilomycin A1 inhibits proteolytic cleavage and hydration but not yolk crystal disassembly or meiosis during maturation of sea bass oocytes.
Oocytes of the black sea bass, Centropristes striata, were enlarged in volume more than three-fold over a 24-hr period during oocyte maturation, both in vivo and in vitro. At the same time, the opaque oocytes clarified while the crystalline yolk inclusions lost their ordered structure, fused with one another, and formed a continuous electron-lucent mass. The oocyte size increase was due almost entirely to water uptake, which was accompanied by the accumulation of Na+, K+, and free amino acids (FAAs). The absolute amounts of each of these small molecular weight osmotic effectors increased 2x, 4x, and over 10x, respectively, indicating that the generation of FAAs is the major cause of water uptake during maturation. Amino acid analyses indicated that the amounts of all amino acids except taurine increased, so that selective amino acids were not produced during maturation. The increase in FAAs was accompanied by the loss of certain high-molecular-weight yolk proteins and the generation of many smaller peptides. Oocytes stimulated to undergo maturation in the presence of bafilomycin A1, a specific inhibitor of the vacuolar ATPase-dependent proton pump, clarified and underwent maturation but did not increase significantly in size. Cytological examination revealed that yolk crystals fused and became homogeneous but maintained their electron density. No evidence of proteolysis was found in bafilomycin A1-treated oocytes and the generation of FAAs together with hydration was inhibited in a dose-dependent manner (I50 = 3 nM bafilomycin A1). Taken together, we postulate that the pronounced oocyte hydration in marine teleosts that spawn pelagic (floating) eggs is accomplished by a two-step process whereby (i) K+ influx promotes yolk crystal disassembly and yolk sphere fusion and (ii) acidification of the yolk spheres activates yolk proteolysis and concomitant hydration. Bafilomycin A1 inhibits only the second step so that many of the events of oocyte maturation, including germinal vesicle breakdown, occur in its presence but oocyte hydration is suppressed.
Animals↗
Biopsychosocial profile of adults with intellectual disability.
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Adolescent↗
Preparation and use of specific antibodies to the beta-I and beta-II subunits of gonadotropic hormone from Fundulus heteroclitus pituitary.
Fundulus heteroclitus naturally spawns with a semilunar periodicity throughout most of the year in its southernmost habitat, an activity that can be maintained in the laboratory. The alpha and two beta subunits comprising F. heteroclitus gonadotropic hormones (GtHs) I and II have been sequenced, and antibodies have been raised against unique peptides found in each of the two beta subunits. On immunoblots of pituitary proteins, each antibody recognizes a single band with a molecular mass of 16-17 kDa, somewhat larger than the deduced sizes (11-13 kDa) of the unglycosylated subunits. Each antibody also recognizes a different subset of pituitary cells in the central (GtH I) and peripheral (GtH II) proximal pars distalis, regions that display the typical tinctorial properties of gonadotrops. The distribution and distinct separation of cells containing GtH beta subunits I and II thus differ from those found for previously described teleost species, most of which are salmonids that engage in a single spawning episode during the year. The availability of these antibodies thus makes F. heteroclitus an inexpensive, easily manipulated model system for studies on the hormonal regulation of fractional spawning common to a large class of commercially important species other than salmonids.
Amino Acid Sequence↗
Effect of GnRH pretreatment on reproductive performance of postpartum suckled beef cows following synchronization of estrus using GnRH and PGF2alpha.
The effect of GnRH pretreatment on estrus detection rate, precision of estrus, and reproductive performance of postpartum beef cows synchronized to estrus using GnRH and PGF2alpha was evaluated. In Exp. 1, Angus cows (n = 87) were randomly assigned by parity, postpartum interval, and body condition score (BCS) to receive either 1) GnRH on d -7 and PGF2alpha on d 0 (GP) or 2) the GP treatment and an additional injection of GnRH on d -16 (GGP). Estrus detection and AI were conducted twice daily from d -3 to d 3. At 72 h after PGF2alpha, all animals not previously detected in estrus were bred by AI and received a concurrent injection of GnRH (TAI). Synchronized pregnancy rates were numerically increased (P = 0.15) in cows treated with GGP (55%) compared with those on the GP treatment (44%). In Exp. 2, 1,276 spring-calving, suckled beef cows in nine herds were randomized to treatments as described for Exp. 1, except that the initial GnRH injection for the GGP treatment was administered on d -14. Herd affected all indicators of reproductive performance (P < 0.05). The percentage of animals detected in estrus prematurely (d -3 to d 0; 7%) was not affected by treatment. Estrus response rate was influenced by postpartum interval (< 60 vs > or = 60; 61 vs 73%; P < 0.01) and a three-way interaction of parity, BCS, and treatment (P < 0.01). Within animals with a BCS > or = 5.5, the GGP treatment tended to increase the detection of estrus in primiparous cows (GP vs GGP; 76 vs 91%; P = 0.11) and decrease detection in multiparous cows (GP vs GGP; 78 vs 72%; P < 0.10). However, because conception rate to TAI in animals with a BCS > or = 5.5 was greater (P < 0.05) in the GGP than in the GP group (28 vs 8%, respectively), this interaction was interpreted to represent a shift in interval to estrus induced by the GGP treatment, rather than a reduction in the synchronization of ovarian function. Conception rates of animals inseminated to an observed estrus did not differ among treatments (P = 0.15). Synchronized pregnancy rate tended (P = 0.06) to be greater in GGP- (53%) than in GP-treated animals (47%). In conclusion, pretreatment with GnRH tended to increase pregnancy rates during a 6-d synchronization period, primarily through enhanced conception rates of cows bred by TAI. In contrast to our hypothesis, GnRH pretreatment did not increase the percentage of animals detected in estrus or the precision of estrus expression.
Animal Husbandry↗
Serotonin inhibition of steroid-induced meiotic maturation in the teleost Fundulus heteroclitus: role of cyclic AMP and protein kinases.
The transduction of the serotonin (5-HT) signal in Fundulus heteroclitus ovarian follicles leading to the inhibition of oocyte meiosis reinitiation (oocyte maturation) in vitro induced by the naturally occurring maturation-inducing steroid 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one (17,20 beta P) was investigated. Steroid-induced oocyte maturation was inhibited by 5-HT in a dose-dependent manner; maximum inhibition (90%) was observed with 10(-4) M 5-HT. Groups of follicle-enclosed oocytes were cultured in the presence of the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX) and treated with increasing doses of 5-HT. Serotonin was found to slightly increase the levels of follicular 3',5'-cyclic adenosine monophosphate (cAMP) in a dose-dependent manner; 10(-4) M 5-HT induced approximately a 3-fold increase in cAMP with respect to the controls. The changes in cAMP were then evaluated in follicles treated with 17,20 beta P in IBMX-free culture media in the presence or absence of 10(-4) M 5-HT. The exposure of follicles to 17,20 beta P alone produced a small and transient reduction in cAMP (40%) within 1-3 hr of steroid stimulation, and these early changes in cAMP appeared associated with a high incidence of germinal vesicle breakdown (80% GVBD) by 24 hr of incubation. Under these conditions, treatment of follicles with 5-HT also increased significantly the production of cAMP, and when 5-HT was combined with 17,20 beta P, the steroid-mediated reduction in cAMP was prevented and the levels of GVBD inhibited by 95%. Meiosis also was reinitiated with either the protein kinase A (PKA) inhibitor H8 or the protein kinase C (PKC) activator PMA, and the 5-HT inhibitory action on GVBD was found to be 100-fold reduced or completely ineffective, respectively. Preincubation of follicles with the PKC inhibitor GF109203x abolished PMA-induced GVBD in a dose-dependent manner, whereas this inhibitor had no effect on 17,20 beta P-triggered meiotic maturation, indicating that activation of PKC is apparently sufficient but not necessary to reinitiate meiosis. Taken together, these findings suggest that 5-HT may inhibit 17,20 beta P-induced meiotic reinitiation through the activation of a cAMP-PKA transduction pathway and that PKC possibly induces oocyte maturation by a different pathway than the steroid and thus is not affected by 5-HT.
Animals↗
Synthesis and preliminary evaluation of MP-2269: a novel, nonaromatic small-molecule blood-pool MR contrast agent.
A nonaromatic, small-molecule, gadolinium(3+)-chelate code named MP-2269 was synthesized and evaluated in animals as a potential MR contrast agent for blood pool. The ligand of MP-2269 was prepared by conjugating a lipophilic, albumin-binding moiety, 4-pentylbicyclo[2.2.2]octane-1-carboxylic acid, to an amino-functionalized DTPA derivative by means of a diaspartic acid linker. Proton relaxometry studies in vitro yielded spin-lattice relaxivities (R1) for MP-2269 of 6.2, 20.0 and 26.1 mM(-1)sec(-1) in water, rabbit blood, and human blood, respectively. The enhanced relaxivities in blood indicate significant binding of the agent to blood proteins. At a dose of 45 micromol/kg, MP-2269 showed a biphasic rabbit blood clearance profile with half-lives of 4.7 and 142 minutes, respectively, for the fast and slow components. In rats, the agent is cleared predominantly through the hepatobiliary pathway (approximately 70% in 24 h by this mode). The LD50 value of MP-2269 is approximately 3.0 mmol/kg in mice. Preliminary MR angiograms obtained in the rabbit showed excellent enhancement of blood vessels. Hence, MP-2269 has potential for future exploitation as a contrast agent for MR angiography.
Animals↗
Development of a novel nonaromatic small-molecule MR contrast agent for the blood pool.
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Animals↗
Oocyte sensitivity to serotonergic regulation during the follicular cycle of the teleost Fundulus heteroclitus.
In the teleost Fundulus heteroclitus, serotonin (5-HT) reversibly inhibits oocyte maturation induced in vitro by the maturation-inducing steroid (MIS) 17,20beta-dihydroxy-4-pregnen-3-one (17,20betaP). The 5-HT inhibition of 17,20betaP-induced meiotic maturation was examined in ovarian follicles at different developmental stages or isolated at different times during the follicular cycle. Steroid treatment of late vitellogenic and early maturing follicles (1.2- to 1.7-mm diameter) promoted oocyte maturation in a size-dependent manner, and this maturation was inhibited by 5-HT in follicles of < 1.6- to 1.7-mm diameter. Thus, the 5-HT inhibition progressively decreased as follicles developed the ability to mature in the absence of 17,20betaP. The effectiveness of 5-HT to increase follicular cAMP remained similar within the same developmental stages, indicating that the reduction of 5-HT inhibitory action was not related to the competence of 5-HT to activate inhibitory signals in the oocyte. During the follicular cycle, fully grown follicles (1.3- to 1.4-mm diameter) showed a decreased maturational competence in response to gonadotropin or MIS stimulation after the follicular recruitment into maturation and spawning occurred, which coincided with an increase of the effectiveness of 5-HT at inhibiting 17,20betaP-induced maturation. In further experiments, preincubation of follicles with hCG was found to reduce 5-HT inhibitory action, but when follicles were incubated with either hCG in the presence of a steroidogenesis inhibitor or estradiol-17beta (E2), the 5-HT inhibition was unaffected. These findings suggest that 5-HT inhibition of the MIS-induced meiotic maturation is not under direct gonadotropin or E2 regulation but that it might be regulated in vivo by changes in the competence of the oocytes to undergo oocyte maturation after MIS stimulation.
Animals↗
Pharmacology of the serotonergic inhibition of steroid-induced reinitiation of oocyte meiosis in the teleost Fundulus heteroclitus.
Serotonin (5-HT) was found to inhibit steroid (17 alpha,20 beta-dihydroxy-4-pregnen-3-one; 17,20 beta P)-induced resumption of oocyte meiosis (oocyte maturation) in vitro in the teleost Fundulus heteroclitus. Serotonin inhibited both follicle-enclosed and denuded oocytes, which indicates the presence of oocyte-associated 5-HT sensitive sites. The response of oocytes to 5-HT was characterized pharmacologically, i.e., the capacity of serotonergic agonists and antagonists to mimic or block the 5-HT inhibition of the steroid-induced oocyte maturation was assessed by the changes in the percentage of oocyte germinal vesicle breakdown (GVBD). Dose-response curves for each compound were drawn and compared. The rank order of potency among the agonists was: 5-HT > 5-methoxytryptamine > tryptamine = 5,6-diHT = 5-carboxidotryptamine > 5,7-diHT = 5-methoxy-dimethyltryptamine > alpha-methyl-5HT > 2-methyl-5HT. Incubation of ovarian follicles with high doses of some antagonists (mianserin and metergoline) induced oocyte GVBD, although this effect was associated with high levels of oocyte atresia during GVBD or shortly after maturation. Consequently, doses of the antagonist too low to induce GVBD were tested for their ability to block the 5-HT inhibitory action; the rank order of potency was: MDL-72222 = metoclopramide > metergoline > propanolol > ketanserin. Dopamine, acetylcholine, epinephrine, and norepinephrine could also inhibit 17,20 beta P-induced GVBD, although at doses much higher than those of 5-HT; melatonin and histamine had no effect on oocyte maturation. These results suggest that specific receptors mediate the inhibitory action of 5-HT on the steroid-triggered meiosis resumption. The pharmacological profile of these 5-HT receptors is different from those of any known mammalian 5-HT receptor, although they showed some similarities to the 5-HT1A, 5-HT2, and 5-HT3 receptors, as well as to 5-HT receptors on oocytes of some bivalve molluscs.
17-alpha-Hydroxyprogesterone↗
The developing Xenopus oocyte specifies the type of gonadotropin-stimulated steroidogenesis performed by its associated follicle cells.
As a response to gonadotropin, amphibian ovarian follicles primarily synthesize and secrete estradiol-17 beta (E2) during vitellogenesis and progesterone (P) when fully grown. Stage IV (vitellogenic) and stage VI (full-grown) ovarian follicles from Xenopus laevis, as well as intermediate sizes, were used to explore this change in steroidogenesis. Optimum steroidogenesis occurred in both stage IV and stage VI follicle exposed for 6 h to 20 IU human chorionic gonadotropin/mL. Although the total amounts of steroid fund were about the same, the E2/P ratios ranged from 26 to 35 for intact stage IV follicles, but only 0.02-0.03 for intact stage VI follicles. Steroid-producing follicle cells were isolated from stage IV and stage VI follicles by non-enzymatic procedures, were washed and were tested for steroidogenic activity in the absence of oocytes. In both cases, P was the predominant steroid produced (E2/P = 0.004-0.04), so the presence of stage IV, but not stage VI, oocytes appears to be necessary for E2 production as a response to gonadotropin. Octanol had no significant effect on the E2/P ratio of intact stage IV follicle. Dissected oocyte/follicle cell preparations from stage IV follicles were also periodically challenged with gonadotropin over 72 h, during which time most follicle cells detached from the oocyte and formed a monolayer over the bottom of the culture dish. The relatively high E2/P ratios for such preparations showed no significant change when stimulated with gonadotropin at various times over the 72 h, as long as the medium was not replaced. We conclude that the estrogenic effect of stage IV oocytes is most likely mediated by a secretory product rather than by gap junctions or by cell contact. Because the X. laevis oocyte has been shown to be a self-differentiating cell, the steroidogenic shift that occurs in developing ovarian follicles appears to be fundamentally regulated by the growing oocyte as if undergoes a physiological change rather than by different gonadotropins.
Animals↗
Neuropeptide Y in the forebrain and retina of the killifish, Fundulus heteroclitus.
The organization of the neuropeptide Y (NPY)-immunoreactive system in the forebrain, pineal organ and retina of a biweekly spawning fish (Fundulus heteroclitus) was investigated. Immunoreactivity was encountered in neurons of the nucleus olfactoretinalis, in the large population of neurons in the floor of the telencephalon, and in the nucleus entopeduncularis. Isolated somata were encountered in the hypophysiotropic hypothalamic nuclei, viz., the nucleus preopticus periventricularis, nucleus preopticus, and nucleus lateralis tuberis. Immunoreactive somata were also seen in the nucleus dorsomedialis thalami. The olfactory bulb was abundantly innervated by NPY fibers. The telencephalon showed thick radiating processes basally and terminal fields with modest to high densities in the dorsal and lateral regions. NPY-immunoreactive fibers were also conspicuous in the preoptic area, suprachiasmatic nucleus, tuberal hypothalamus, pituitary gland, and paraventricular thalamic regions; discrete CSF-contacting sites were also encountered. Of special interest was the occurrence of NPY immunoreactivity in fibers of the pineal stalk and organ. In the retina, some amacrine cells displayed immunoreactivity, while the inner plexiform layer revealed a well-developed pattern of NPY fibers different from that previously described for the goldfish.
Animals↗
Semilunar follicular cycle of an intertidal fish: the Fundulus model.
In their habitat, Fundulus heteroclitus (Cyprinodontidae) spawn against a variety of specific substrates that become available only at spring tides; they thus exhibit a semilunar reproductive cyclicity. In the laboratory at 28 +/- 0.6 degrees C and 14L:10D, this cyclicity is free-running and can be observed by means of daily egg collection and frequent ovarian sampling. Daily egg collection cycles gathered from three different spawning groups were pooled chronologically; the cycles were determined by nonlinear regression sine-curve matching and so were dated from Days -6 to +6, with Day 0 as the peak egg collection day. Ovaries were sampled on Days -6, -4, -2, -1, +1, +2, and +4. The pooled data indicated that early-maturing follicles (1.3- to 1.6-mm diameter) are recruited from a constant reserve of vitellogenic follicles (0.7- to 1.2-mm diameter) and become abundant early in the cycle but are depleted during Days -6 to +4 by the formation of late-maturing follicles and ovulated eggs. A midcycle peak of ovulated eggs in the ovary corresponds to the egg collection peak. This progression of follicles followed by spawning decreases the total count of the follicles (> or = 0.7-mm diameter) and eggs in the ovary by 52% (from 454 to 219 per 10 g of female weight). The semilunar follicular cycle in this Fundulus model thus includes 1) an early-cycle follicle recruitment, 2) an early- and midcycle follicle maturation, and 3) a midcycle egg ovulation and spawning. This follicular cycle also proceeds in fish deprived of a spawning substrate. A female in the wild would thus execute the follicular cycling in a timely sequence, in anticipation of each recurring spring tide, whether or not a natural substrate becomes available. We conclude that F. heteroclitus provides a useful nonmammalian model for the study of cyclic reproductive activity in the laboratory.
Animals↗