Biomedical subjects

L S Katz

Publications and source records attributed to L S Katz.

At least 19 recordsLinked to original sources

PubMed2000

Expression of PTTG and prc1 genes during telencephalic neurogenesis.

We present the first time/space analysis using in situ hybridization for PTTG and prc1 genes during development of the mouse telencephalon. During the stages E11.5-E13.5 PTTG and prc1 are expressed in most tissues of the embryo. Within the telencephalon, PTTG and prc1 are found exclusively inside of the ventricular zone (VZ). The intensity of the expression of both genes in the ventricular zone reaches its peak by E15.5. Expression starts to decrease by E18.5, it is still visible at least up to P2 and not detectable in the adult brains. Expression of the prc1 gene, but not that of the PTTG, is also found in the mitoticaly active cells outside of the VZ within the telencephalon. Most of the cells expressing the PTTG gene were found in the lower part of the ventricular zone suggesting that the level of PTTG mRNA is regulated during different phases of the mitotic cycle.

Animals↗

PubMed2000

Role of the vomeronasal organ in neonatal offspring recognition in sheep.

Twenty-five pregnant Dorsett ewes were randomly divided into three groups to test if ewes use their vomeronasal organs for offspring recognition during nursing. One group of eight ewes (procaine) were made anosmic by irrigation of the nasal olfactory apparatus with a zinc sulphate procaine solution. The second group of nine ewes (cauterized) had their vomeronasal organs rendered nonfunctional by cauterization of the nasoincisive duct. The third group of eight ewes were the controls. Parturition was synchronized in all ewes with betamethasone on Day 145 of gestation. Maternal responsiveness was tested two separate times with 1- to 2-day-old alien lambs. Each alien lamb trial was conducted 24 h apart. Cauterized ewes allowed alien lambs to suckle and they were unable to distinguish alien lambs from their own lambs, whereas the ewes in both groups with functional vomeronasal organs (procaine and control) violently rejected any alien lamb's attempt to suckle. Thus, female sheep use their vomeronasal organs for neonatal offspring recognition.

Animals↗

PubMed1999

Scent of a Ewe: transmission of a social cue by conspecifics affects sexual performance in male sheep.

Unlike males from other domestic species, domestic rams (Ovis aries) are not sexually stimulated, as determined by measuring sexual performance, following the opportunity to watch a copulating pair. Previously, we reported that aspects of ram sexual performance were improved when rams interacted with a male conspecific that had mated an estrous ewe. Whether the cues were gender-, estrous state-, or behavior-related was tested in this study. Sexually experienced rams were exposed to male pen mates that had interacted with an estrous ewe, a non-estrous ewe, an estrous ewe with a cloth perineal patch, or a ram, or that had been placed alone in a small pen. The rams were then tested for sexual performance. Rams performed more olfactory investigative behaviors toward pen mates that had interacted with a ewe, regardless of her estrous state, than toward a pen mate that had been exposed to another male. Rams exposed to pen mates that had interacted with a ewe also had shorter postejaculatory and interejaculation intervals and subsequently achieved more ejaculations in standardized sexual performance tests. Results from this experiment confirm that male-male interactions affect sexual performance in male sheep and that olfactory cues likely account for the transfer of information among individuals.

Animals↗

PubMed1999

Facilitation of sexual behavior in French-Alpine goats treated with intravaginal progesterone-releasing devices and estradiol during the breeding and nonbreeding seasons.

The effectiveness of administering progesterone (P4) using controlled intravaginal drug release (CIDR) devices on estradiol (E2)-induced sexual behaviors was examined in ovariectomized (ovx) French-Alpine goats during the fall and spring. Estradiol-induced attractivity and receptivity were facilitated during the spring when P4-filled CIDR devices were removed 24 or 48 h before injection of 30 microg of E2. During the fall, attractivity was also facilitated by CIDR removal 24 h prior to E2 injection, whereas E2-induced receptivity was unaffected by removal of the CIDR at this interval. Concentrations of P4 in circulation during the 3 d of treatment with a CIDR were similar to those during the late luteal phase of the estrous cycle in intact goats. Treatment with P4-filled CIDR for 3 d, followed by injection with 30 microg of E2 24 h after removal, was determined to be a useful model for inducing sexual behavior in a physiologically relevant manner, and it may also be an effective means for facilitating estrus detection due to the high frequency of display of sexual behavior during a predictable time period following steroid treatment.

Administration, Intravaginal↗

PubMed1997

Progesterone facilitation and inhibition of estradiol-induced sexual behavior in the female goat.

The effect of progesterone (P4) on estradiol (E2)-induced sexual behaviors in ovariectomized French-Alpine goats, during both the breeding (fall) and the nonbreeding (spring) seasons, was examined. Progesterone facilitated E2-induced attractivity and receptivity in the nonbreeding season when P4 treatment occurred 48 or 72 hr prior to treatment with E2. During the breeding season, P4 facilitated attractivity when treatment occurred 72 hr prior to E2 injection. In contrast, P4 inhibited all sexual behaviors when treatment occurred 12 or 24 hr prior to injection of E2. Progesterone did not facilitate E2-induced proceptivity in either the breeding or the nonbreeding seasons. These findings demonstrate that both season and temporal sequence of P4 and E2 administration affect sexual behavior in ovariectomized French-Alpine goats.

Animals↗

PubMed1994

Exposure to constant photoperiod alters serum prolactin concentrations and behavioral response to estradiol in the ovariectomized goat.

The effects of constant photoperiod on serum prolactin concentrations and sexual behavior of ovariectomized goats was investigated. Fourteen ovariectomized goats were divided into groups of seven goats each and placed in photoperiod-controlled rooms with either 8L:16D or 16L:8D. All goats received six estradiol (E2) treatments in a Latin square design. Following each treatment six 1-h observation periods were conducted. Blood was collected before E2 treatment and at each observation period for prolactin quantification. During the observation periods measures of attractivity, proceptivity, and receptivity were recorded. Goats exposed to 8L:16D displayed sexual behavior in response to doses of E2 lower than those required by goats exposed to 16L:8D. Prolactin concentrations were higher in goats exposed to 16L:8D than in those exposed to 8L:16D. It was concluded that photoperiod affects prolactin concentrations and behavioral sensitivity to E2 in goats. The effect of continued exposure to constant photoperiod on these variables was then investigated. The goats were held in constant photoperiod for 211 d and behavior tests as described for Exp. 1 were repeated. Scores for attractivity, proceptivity, and receptivity did not differ between the two groups after 211 d of exposure to constant photoperiod. Prolactin concentrations did not differ in this study between the two groups. It was concluded that after chronic exposure to 8L:16D ovariectomized goats become refractory to the stimulatory effects of short photoperiod.

Animals↗

PubMed1994

Effects of bromocriptine treatment on the expression of sexual behavior in male sheep (Ovis aries).

Twenty-three rams were treated twice daily with subcutaneous injections of bromocriptine or vehicle over 30 d during two seasons, spring and fall. Sexual behavior was observed and quantified to determine the effects of bromocriptine-induced hypoprolactinemia on mount attempt (MA), mount (M), and ejaculation (E) frequency of the rams upon exposure to estrous ewes. Behavioral responses and serum prolactin (PRL) concentrations were determined on a weekly basis before, during, and after the treatment period in each season. Treatment with bromocriptine caused a significant decrease in serum concentrations of PRL during both seasons (P < .01). Post-treatment period concentrations of PRL returned to pretreatment levels during the spring, whereas during the fall, post-treatment period PRL concentrations remained low (P < .05). The frequency of MA and M was lower during bromocriptine treatment relative to control rams in the spring (P < .05). The frequency of MA and M returned to pretreatment values after bromocriptine treatment was withdrawn. Ejaculation frequency tended to decrease during and after bromocriptine treatment relative to controls (P < .09). There was no effect of bromocriptine treatment on frequency of MA and M during the fall. During the fall, the frequency of E tended to decrease in bromocriptine-treated rams (P < .1). These data indicate that bromocriptine-induced hypoprolactinemia is associated with a significant diminution in expression of sexual behavior in rams. It is suggested that PRL modulates the intensity of expression of sexual behavior in rams, and this effect may be season-dependent.

Animals↗

PubMed1994

Cortisol increases in plasma of Holstein heifer calves from handling and method of electrical dehorning.

Changes in cortisol in plasma were used to assess stress when calves were restrained and then dehorned. Thirteen Holstein heifer calves between 3 and 4 wk of age were used over 4 d; each calf served as its own control. On d 1, 2, and 4, blood was sampled initially while calves were in a pen, 5 min after being placed in a restraint chute, and then at 5, 15, 30, and 45 min and 1, 2, 3, 4, 8, and 12 h after simulated or actual dehorning. On d 1, dehorning was simulated. On d 2 and 4, one horn bud of each calf was cauterized, respectively; sequence of horns (right, left) and dehorning instruments (conventional electrical, Buddex) were alternated for all calves. Day or previous dehorning procedures had no effect on initial concentrations of cortisol in plasma. However, after calves were placed in a chute, cortisol in plasma increased with each entrance. Cortisol in plasma peaked at 5 min posthandling (d 1, 11.3 ng/ml) or 15 min postdehorning (electrical, 21.9 ng/ml; Buddex, 20.7 ng/ml). These data suggest that both dehorning procedures resulted in similar rates of synthesis and secretion of cortisol.

Animals↗

PubMed1994

Effects of substance abuse on hallucination rates and treatment responses in chronic psychiatric patients.

BACKGROUND: Few data systematically document the effects of illicit drug exposure on psychotic illness. We examined the effect of substance abuse on rates and treatment responses of hallucinations in a chronic psychiatric population. METHOD: 113 cooperative patients consecutively admitted to a state psychiatric hospital were administered the Structured Clinical Diagnostic Interview for DSM-III-R, a Hallucination Interview, and an inventory of past and current substances of abuse. Demographic information was obtained on 104 of 108 patients who declined interview. Medication dosage was analyzed for one third of the interviewed sample; hospital records, nursing reports, contacts with relatives, and urine drug screens were used to confirm information from patient interviews. Hallucination rates and response were compared by diagnostic groups (chi-square). RESULTS: Noninterviewed patients had more frequent hospitalizations, more patients diagnosed with psychosis not otherwise specified or schizoaffective disorder, and fewer females with comorbid substance abuse than the study population. Among interviewed subjects, those with substance abuse and psychiatric illness had first admissions at an earlier age than patients with no substance abuse (p = .005). Schizophrenics experienced higher rates of visual (p = .04) and olfactory (p = .05) hallucinations when using illicit drugs. Substance abuse was associated with decreased treatment responsiveness of auditory (p < .03) and tactile (p < .004) hallucinations in schizophrenic or manic patients. Compared with nonparanoid patients, there was a trend for paranoid schizophrenics with substance abuse to experience more frequent visual (p = .09) and tactile (p = .06) and more refractory auditory (p = .08) hallucinations. No differences in medication dosages were found between patients with treatment-responsive and treatment-refractory hallucinations. CONCLUSIONS: Abused substances may interact selectively with primary psychiatric illness to increase rates and treatment resistance of specific hallucination modalities; etiologies are discussed.

Adult↗

PubMed1993

Evidence for a role of the liver in the luteotropic action of prolactin in rats.

Recent studies indicate that the liver may participate in growth-promoting and lactogenic activity of prolactin (PRL). Accordingly, our study was designed to determine whether the liver participates in the luteotropic activity of the hormone in rats. Normally cycling Long-Evans rats received infusions of solvent or 50 micrograms ovine (o) PRL per day into either the external jugular vein (EJV) or the hepatic portal vein (HPV) via osmotic minipumps. The modes of delivery were continuous, 2 pulses of 8 h each per day (2-8), or 4 pulses of 2 h each per day (4-2). Observation of daily vaginal smears was used to classify rats as either cyclic or predominantly diestrus (PD). In a second study, rats fitted with osmotic minipumps received oPRL or vehicle as above, and serial blood samples were obtained for measurement of serum oPRL and rat (r) PRL concentrations. Estrous cycles of normal length were observed in 9 of 11 rats (82%) receiving solvent infusions. All 8 animals receiving continuous oPRL infusions were classified as PD, regardless of site of infusion. In addition, in 4 of 5 (80%) HPV-infused and 5 of 6 (83%) EJV-infused rats on the 2-8 pulse schedule, the smear patterns were classified as PD. However, when rats received 4-2 EJV, 9 of 13 animals (69%) were classified as cyclic, whereas 9 of 11 rats (82%) were classified as PD when oPRL was similarly pulsed into the HPV. Differences in serum concentrations of oPRL between oPRL-treated and vehicle-infused rats were significant only for continuously infused animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

Effects of bromocriptine-induced hypoprolactinaemia on gonadotrophin secretion and testicular function in rams (Ovis aries) during two seasons.

The influence of low circulating concentrations of prolactin on gonadotrophin and testosterone secretion, sperm production and testicular growth was investigated in rams during two different seasons. Treatment of Dorset rams (n = 23) with bromocriptine (4 mg day-1) during the spring (n = 11) and autumn (n = 12) caused a significant decrease in basal, mean and total serum prolactin concentrations (P < 0.01). In spring, serum prolactin concentrations returned to pretreatment values, one week after the termination of treatment. Basal, mean and total serum concentrations of LH were significantly higher in treated rams than in controls during the treatment period in autumn (P < 0.05). Secretion of LH was not affected by bromocriptine treatment during spring. There were no differences in the secretion of FSH between treated and control rams in either season. Serum concentrations of testosterone were significantly lower in treated rams than in control rams during the treatment period in autumn (P < 0.05) but not during spring. Semen volume from treated rams was significantly lower during the period after treatment in autumn (P < 0.05). Scrotal circumference decreased during both seasons in treated animals, but this change in size was significant only during spring (P < 0.05). Conversely, there was an increase in scrotal circumference in control rams during both seasons. It is concluded that prolactin may (i) affect LH secretion and, (ii) influence testicular function in rams, by directly affecting testosterone and semen production during autumn, and retarding testicular growth in spring.

Animals↗

PubMed1992

Sexual behavior of farm animals.

The field of sexual behavior of domestic farm animals is discussed with emphasis on studies of cattle, sheep and goats. Descriptions are provided of behaviors related to the attractivity, proceptivity and receptivity of females, as well as environmental and physiological factors influencing both male and female sexual behavior. The organizational and activational actions of steroid hormones on behavior are also reviewed.

Journal Article↗

PubMed1992

Organophosphate-induced alterations in muscarinic receptor binding and phosphoinositide hydrolysis in the human SK-N-SH cell line.

Low level, chronic exposure (0.1 nM, 24 hrs) to the organophosphate paraoxon significantly inhibits N-[3H]methylscopolamine ([3H]NMS) binding to muscarinic receptors in a noncompetitive manner in the SK-N-SH neuroblastoma cell line. The effect of paraoxon on muscarinic receptor-mediated phosphoinositide hydrolysis was also investigated. At 0.1 nM, paraoxon caused a time-dependent increase in the accumulation of inositol phosphates, while the classical muscarinic receptor agonist carbachol was virtually ineffective at low concentrations. In contrast, carbachol-induced increases in phosphoinositide hydrolysis at higher concentrations (1 mM) were markedly larger (five-fold) than the increases induced by PX. Approximately 50% of the maximal increase in the accumulation of inositol phosphates due to paraoxon treatment was antagonized by saturating concentrations of muscarinic receptor antagonists, while the response to carbachol was completely antagonized. In addition, chronic treatment (24 hrs) of SK-N-SH cells with pertussis toxin blocked 75% of the stimulatory effects of carbachol, but inhibited only 38% of the paraoxon-induced response. Neomycin, a phospholipase C inhibitor, completely blocked both the paraoxon and carbachol-induced stimulation of phosphoinositide hydrolysis. The results suggest that paraoxon can modulate signal transduction by indirect activation of muscarinic receptors as well as by acting at a distal site along the pathway.

Acetylcholinesterase↗

PubMed1990

Molecular forms of acetylcholinesterase in subcortical areas of normal and Alzheimer disease brain.

We have previously reported that the 10s molecular form (G4) of acetylcholinesterase (AChE) is selectively lost from several cortical areas of Alzheimer's disease (AD) brain. In the current follow-up study, we microdissected several areas of nondemented and AD brain, including the hippocampus, amygdala, and cingulate gyrus. Tissue homogenates were separated on sucrose density gradients and the resulting fractions were analyzed for AChE activity in order to define the ratios of the predominant AChE molecular forms (G4/G1). Both the hippocampus and amygdala exhibited distinct patterns of alterations in the G4/G1 ratio which correlate with the known distribution of histopathological changes in AD brain. In order to further define the major pool of AChE that is depleted in AD, we separated fractionated tissue homogenates into salt-soluble and detergent-soluble fractions. The G4/G1 ratios were only altered in the detergent-soluble fractions, indicating that the loss of the G4 AChE molecular form involves a selective depletion of the membrane pool. Available evidence would suggest that this form is the AChE molecular form physiologically relevant at the cholinergic synapse.

Acetylcholinesterase↗

PubMed1990

Evidence for a role of the liver in the mammotrophic action of prolactin.

The possibility that the liver plays a role in the growth-promoting actions of PRL on the mammary lobuloalveolar (L-A) system was investigated using 6-week-old female rats. Chronic indwelling catheters were inserted into the external jugular vein (EJV) or the hepatic portal vein (HPV) and attached to osmotic minipumps, which were used to infuse pulses of ovine (o) PRL (4/day of 2 h each, total dose = 20 micrograms/day) for 14 days. The rats were hypophysectomized 2 days after catheterization, and given daily sc injections of estradiol + progesterone in oil (2 micrograms and 5 mg/day, respectively) plus twice daily ip injections of porcine GH (50 micrograms/injection) from days 2-13. They were killed on day 14. Controls received the sc and ip hormone injections but were given solvent infusion into the EJV or the HPV instead of oPRL. Infusion of the oPRL into the EJV did not promote mammary L-A growth more than did infusion of solvent into either the EJV or the HPV. By contrast, infusion of the same dose of the hormone into the HPV caused a significant stimulation of the L-A growth. Serum insulin-like growth factor-I (IGF-I) levels were measured by RIA in the rats given the same hormone injections with either intrahepatic infusion of solvent or oPRL, but terminated 7 days after the start of infusion. Intrahepatic delivery of oPRL was not more effective at elevating serum IGF-I concentrations than was the infusion of solvent. These results indicate that the liver may participate in the mammotrophic actions of PRL and serum IGF-I is not responsible for this effect.

Animals↗

PubMed1989

Modulation of central muscarinic receptor binding in vitro by ultralow levels of the organophosphate paraoxon.

Homogenates of calf caudate nuclei were found to contain at least three distinct subclasses of cholinergic, muscarinic receptors. These subtypes, labeled with [3H]quinuclidinyl benzilate (QNB), can be separated by rapid filtration with the use of the selective ligands, pirenzepine, AF-DX116, and 4-DAMP which have high affinity for the M1, M2, and M3 subtypes, respectively. Paraoxon was found to modulate [3H]QNB binding in a noncompetitive manner at concentrations below those needed to affect acetylcholinesterase activity. Pretreatment of the membrane protein with high concentrations of both the M2 selective antagonist, AF-DX116, and the M3 selective antagonist, 4-DAMP, protected against paraoxon inhibition of [3H]QNB binding, while the M1 selective antagonist pirenzepine did not. Paraoxon sensitive sites, M2 and M3, are found predominantly on presynaptic neurons in the central nervous system. It is postulated that blockade of these sites may interfere with negative feedback inhibition of acetylcholine release and facilitate the development of behavioral and motor deficits that may be associated with chronic exposure to low levels of organophosphates.

Animals↗

PubMed1988

Sexual performance of rams reared with or without females after weaning.

The objective of this study was to determine the effect of postweaning exposure to females on the subsequent sexual performance of young rams. Twenty-five crossbred rams were reared in a group with ovariectomized females from 4.5 to 9 mo of age. Ewes were brought into estrus every 2 wk during this period. A companion group of 23 crossbred rams was not exposed to females following weaning. Four 30-min sexual performance tests were administered at 10 mo of age. Rams reared with males and females (RMF) exhibited more mounts (P less than .001) and more ejaculations (P less than .002) than rams reared only with males (RM). The frequency of successful matings by the latter group did not increase with experience. Nine rams were sexually inactive in the sexual performance tests. Follow-up tests revealed that two of the RMF rams and one RM ram developed and maintained a sexual preference for males. The six remaining rams eventually mated with females when tested in familiar pens and subsequently exhibited normal levels of sexual performance even when tested in an unfamiliar enclosure. Exposure to ewes during the postweaning prepubertal period enhanced sexual performance. However, early exposure to females did not ensure that all males developed sexual preferences for females. The environmental context in which sexual performance tests are administered may inhibit the expression of heterosexual behavior in a small percentage of animals. After heterosexual behavior was expressed, the rams continued to show normal levels of sexual performance.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1987

Endocrine systems and behavior.

Estradiol, either directly from the ovary of females or as a metabolite of testosterone from the testes of males, seems to be the necessary and probably sufficient endocrine signal for sexual differentiation and adult sexual expression. Progesterone, in females, may play an important priming or facilitative role prior to estrus, especially following pregnancy, when blood estrogen levels are high for a prolonged period. At high doses, progesterone clearly inhibits the expression of sexual behavior.

Aggression↗