Biomedical subjects

J M Stern

Publications and source records attributed to J M Stern.

At least 37 records · Page 2Linked to original sources

PubMed1998

Functions of the caudal periaqueductal gray in lactating rats: kyphosis, lordosis, maternal aggression, and fearfulness.

Severe impairment of the kyphotic nursing posture in lactating rats found previously after prepartum lesions of the caudal intercollicular periaqueductal gray (cPAG-x) was confirmed and was extended to a continuous 24-hr period. Litters of cPAG-x dams gained approximately 10% less weight postnatally than controls, which was in part related to their dams' compensatory prone nursing posture that was ineffective for milk letdown. Sexual proceptivity and receptivity (lordosis) during the postpartum estrus were virtually eliminated in subjects with relatively large bilateral cPAG lesions. The doubling of maternal attacks toward a male intruder after lesioning was also confirmed and was related to reduced fearfulness in an elevated plus-maze. Thus, the cPAG plays a multifaceted role in parturient rats; it is involved in the mediation of nursing, sexual, aggressive, and fear behaviors.

Aggression↗

PubMed1998

Homocysteine associated hypercoagulability and disseminated thrombosis--a case report.

The authors report the occurrence of vascular occlusion due to hyperhomocysteinemia without significant underlying atherosclerotic disease. This unique observation supports the potential of hyperhomocysteinemia to induce thrombosis and the independence of the thrombosis from hyperhomocysteinemia's associated atherosclerosis. The case demonstrates the clinical relevance of the effects of hyperhomocysteinemia on the coagulation cascade. A 42-year-old woman who lacked signs of classic homocystinuria developed disseminated thrombosis with a 24-hour urine homocysteine concentration of 384 mg, twelve times the upper limit of normal. Thrombosis was present in the aortic arch and its major branches and in the mesenteric arteries and veins. A fatal stroke resulted from the thrombosis. Autopsy revealed minimal atherosclerotic disease and no complicated plaques. This case demonstrates an expanded role of hyperhomocysteinemia in clinically significant vascular occlusion. Serum homocysteine concentration determination may be a factor in the evaluation of a hypercoagulable state. Hyperhomocysteinemia should be considered when evaluating arterial or venous thrombosis in a young person regardless of whether atherosclerosis or other signs of abnormal homocysteine metabolism are present.

Adult↗

PubMed1997

Publication bias: evidence of delayed publication in a cohort study of clinical research projects.

OBJECTIVES: To determine the extent to which publication is influenced by study outcome. DESIGN: A cohort of studies submitted to a hospital ethics committee over 10 years were examined retrospectively by reviewing the protocols and by questionnaire. The primary method of analysis was Cox's proportional hazards model. SETTING: University hospital, Sydney, Australia. STUDIES: 748 eligible studies submitted to Royal Prince Alfred Hospital Ethics Committee between 1979 and 1988. MAIN OUTCOME MEASURES: Time to publication. RESULTS: Response to the questionnaire was received for 520 (70%) of the eligible studies. Of the 218 studies analysed with tests of significance, those with positive results (P < 0.05) were much more likely to be published than those with negative results (P > or = 0.10) (hazard ratio 2.32 (95% confidence interval 1.47 to 3.66), P = 0.0003), with a significantly shorter time to publication (median 4.8 v 8.0 years). This finding was even stronger for the group of 130 clinical trials (hazard ratio 3.13 (1.76 to 5.58). P = 0.0001), with median times to publication of 4.7 and 8.0 years respectively. These results were not materially changed after adjusting for other significant predictors of publication. Studies with indefinite conclusions (0.05 < or = P < 0.10) tended to have an even lower publication rate and longer time to publication than studies with negative results (hazard ratio 0.39 (0.13 to 1.12), P = 0.08). For the 103 studies in which outcome was rated qualitatively, there was no clear cut evidence of publication bias, although the number of studies in this group was not large. CONCLUSIONS: This study confirms the evidence of publication bias found in other studies and identifies delay in publication as an additional important factor. The study results support the need for prospective registration of trials to avoid publication bias and also support restricting the selection of trials to those started before a common date in undertaking systematic reviews.

Biomedical Research↗

PubMed1997

Role of the midbrain periaqueductal gray in maternal nurturance and aggression: c-fos and electrolytic lesion studies in lactating rats.

the upright, crouched, or kyphotic, nursing posture of lactating rats is dependent on suckling stimulation from pups. Because of the neuroanatomical connections of the periaqueductal gray (PAG) and its sensorimotor integration of the analogous lordosis posture displayed by sexually receptive female rats, the possible role of the PAG in kyphosis was investigated using c-fos immunocytochemistry and electrolytic lesions. Lactating rats interacting with and nursing a litter of suckling pups showed greater Fos-immunoreactive nuclei in the lateral and ventrolateral caudal PAG (cPAGl,vl) compared with dams receiving nonsuckling somatosensory, distal, or no stimulation from pups. In contrast, this pattern was not evident in the rostral PAG, where the highest Fos levels occurred in nonsuckled dams, or in five other brainstem sites with either no group differences (peripenduncular, dorsal raphe, and pontine nuclei) or negligible Fos (ventral tegmental area, spinal trigeminal nuclei). After bilateral electrolytic lesions of the cPAGl,vl during gestation or on day 7 postpartum, active maternal behaviors, such as retrieval and licking of pups, and total nursing time were essentially normal. Kyphotic nursing, however, was reduced by 85%, nursing in prone and supine postures increased substantially, and 24 hr litter weight gains were reduced, particularly early in lactation (by 26%). Furthermore, lesioned rats attacked a strange male twice as often as controls did, which is suggestive of reduced fearfulness. These results extend the known roles of the PAG in reproductive and defensive behaviors to the postural control of suckling-induced kyphotic nursing and the modulation of maternal aggression.

Aggression↗

PubMed1997

Trigeminal lesions and maternal behavior in Norway rats: III. Experience with pups facilitates recovery.

In lactating rats, upper snout desensitization by trigeminal denervation severely impairs maternal behavior, with substantial recovery 12-24 hr later. The potential effects of interaction with pups on this recovery was investigated. Dams were subjected to bilateral infraorbital denervation or sham surgery on Day 5 postpartum and observed for 30 min with 6 foster pups 24 hr later, after separation from pups for 4 or 24 hr. Long separation reduced likelihood of retrieval and nursing behavior, infraorbital denervation reduced duration of pup licking, and these deprivations combined greatly increased latencies of pup sniffing and durations of facial self-grooming. Both conditions, and especially their combination, prolonged retrieval duration, the retrieval sequence being interrupted by other pup contact, such as licking. Thus, interaction with pups and adequate trigeminal stimulation maintain normal maternal behavior. These findings are possibly relevant to the normal decline of maternal responsiveness during late lactation and to other lesion-induced deficits.

Analysis of Variance↗

PubMed1997

Offspring-induced nurturance: animal-human parallels.

Offspring provide mothers with stimuli that impel their own nurturance. In rats, distal sensory stimuli from pups--sight, sound, odor--contribute to contact-seeking, whereas tactile stimuli from pups to dam's snout and ventrum elicit essential maternal behavioral reflexes involved in retrieval, licking, and the quiescent, upright nursing posture (kyphosis). Brain sites involved with maternal behavior--assessed by lesions, immunocytochemical visualization of gene activity, and neurophysiological mapping--include the midbrain central gray, medial preoptic nucleus, limbic system, and somatosensory cortex; these may change with experience. Human mothers inadvertently learn to identify their own baby rapidly after birth and can do so via a single sensory modality. Subsequently maternal responsiveness and gratification are impaired by inappropriate, insufficient, or nonreciprocal interactions such as occurs when the baby cries excessively, is blind, deaf, or autistic. Thus, maternal behavior characterized by elicited responses and emotional reactions to stimuli from offspring may be evolutionarily conserved.

Adult↗

PubMed1997

Somatosensory contributions to c-fos activation within the caudal periaqueductal gray of lactating rats: effects of perioral, rooting, and suckling stimuli from pups.

In lactating rats, the immediate-early gene c-fos was previously shown to be highly activated in several brain sites by physical interaction with either suckling or nonsuckling pups but not by distal stimuli from pups, a non-pup stimulus, or no stimulation. Further, even greater levels of Fos-immunoreactivity (ir) occurred following suckling versus nonsuckling contact with pups in only 1 of over 25 sites--the caudal periaqueductal gray (cPAG) at an intercollicular level, lesions of which severely reduced the typical suckling-induced kyphotic nursing posture. Herein we further evaluated the effects and site-specificity of various somatosensory cues received from pups during 60 min on Fos-ir in the PAG of day 7 postpartum rats after a 48-h dam-litter separation. Dams interacting with suckling versus nonsuckling pups showed relatively high numbers of Fos-ir cells in the intercollicular cPAG site identified earlier, but not in three other rostrocaudal planes of the PAG. Elimination of rooting on the dam's ventrum by use of fully anesthetized pups did not further diminish Fos-ir in maternally behaving, nonsuckled dams. Perioral anesthesia of dams prior to reunion with the litter prevented retrieval and licking of pups but not pup-initiated nursing behavior, the duration of which was positively correlated with Fos-ir levels within the intercollicular cPAG. Thus, various somatosensory stimuli from pups activate c-fos in a discrete region of the cPAG but only interactions that include suckling and its behavioral consequences elicit maximal expression, consistent with a role for this midbrain site in the sensorimotor control of kyphotic nursing in rats.

Animals↗

PubMed1996

Nursing behavior in rats is impaired in a small nestbox and with hyperthermic pups.

The supine nursing posture, which occurs increasingly as growing pups initiate nursing from their recumbent dam, was demonstrated to require more space than that provided in earlier studies of mother-young contact (e.g., Leon, Croskerry, & Smith, 1978). Further, hyperthermic rat pups were shown to be deficient in eliciting normal nursing behavior. During a 4-hr separation from their dam, 7-day-old rat pups were incubated at 34 degrees C (nest temperature) or at 39 degrees C (WARM). Compared to controls, WARM-litter dams showed increased licking of and hovering over pups and decreased upright crouching, while WARM litters showed decreased nipple attachment and weight gain. On Day 13, similar effects occurred after incubation at 39 degrees C (vs. 34 degrees C), but not at 36 or 38 degrees C. The results stress the need for ethologically meaningful conditions and direct behavioral observations to reveal the importance of pup activity in the mother-young dyad.

Animals↗

PubMed1996

Trigeminal lesions and maternal behavior in Norway rats: II. Disruption of parturition.

Profound deficits in maternal behavior occur following postpartum bilateral infraorbital denervation (IO-X), with substantial recovery 12-24 h later. In the present experiment, primiparous rats were subjected to IO-X or sham surgery on gestation day 22. Whereas parturition behavior was normal in controls, it was severely disrupted in all IO-X dams. Impairments included absent, abbreviated, or delayed perioral behaviors-nest building, participation in delivery, placentophagia, licking and retrieval of pups-accompanied by increased general activity and delayed onset of nursing. There was increased mortality in the litters of IO-X dams at birth and by postpartum day (PD) 3, and impaired retrieval by IO-X dams on PD1-3. A surgery-birth interval of < 7 h vs. > or = 22 h was associated only with poor litter growth. Thus, prepartum IO-X disrupts onset of maternal behavior during parturition, with long-term consequences for offspring well-being.

Animals↗

PubMed1996

Group processes in a case discussion workshop for community psychiatric nurses.

This paper describes a case discussion workshop with a team of hospital-based community psychiatric nurses (CPNs). After describing the growth of the CPN movement in Britain and the conflicting ideas surrounding the professional role of CPNs, some of the group processes within a particular group of CPNs will be illustrated. Particular attention is paid to the way in which reading material distributed to the group may reflect group processes, and the way in which institutional factors impinge on case discussions. The case for various forms of psychodynamic input into community psychiatric teams is also made.

Community Health Nursing↗

PubMed1996

The epilepsy of trisomy 9p.

Trisomy 9p is associated with structural abnormalities of the brain, neurologic dysfunction, and epilepsy. This report of a 27-year-old man with trisomy 9p and complex partial epilepsy is the first with a detailed description of the epilepsy associated with trisomy 9p. The patient's EEG shows multifocal independent spike discharges and an asymmetric generalized spike discharge. In the first MRI obtained on an adult with this disorder, we find poorly developed white matter, an atrophic corpus callosum and cerebellum, and a choroidal fissure cyst.

Adult↗

PubMed1996

Bone density loss during treatment of chronic GVHD.

Nine adult patients 31-47 (median 39) years of age treated with prednisone and cyclosporin A (CsA) for chronic graft-versus-host disease (GVHD) were evaluated for biochemical factors associated with skeletal turnover at initiation of immunosuppressive therapy (3 months after marrow transplant) and 9 months later (follow-up). Absorptiometry studies of the wrist and lumbar spine were also performed. Serum levels of 1,25-dihydroxycholecalciferol (1,25(OH)2D) were decreased at enrollment, particularly in the six males. Values for all nine patients remained low at follow-up. Levels of serum 25-hydroxycholecalciferol (25(OH)D), parathyroid hormone, and ionized calcium were normal at enrollment and follow-up. Mean urine hydroxyproline and calcium levels were elevated at enrollment, suggesting increased bone resorption; the mean values decreased to the high normal range at follow-up. Urine magnesium excretion was elevated in eight of nine patients at baseline and remained elevated at follow-up in three of eight evaluable patients. Single and dual photon absorptiometry of the wrist and spine, respectively, and dual energy X-ray absorptiometry of the spine, were utilized to evaluate bone mineral density over time. The precision of these tests was, respectively, +/- 3.5%, +/- 3.1% and +/- 1.0%. Results showed a significant ( > 2.5 times the precision) decrease over 9 months in bone mineral density in three of five evaluable males and all three females. The findings indicate increased collagen and bone turnover, increased urinary magnesium and calcium excretion and a significant risk of osteoporosis in patients receiving treatment for chronic GVHD. Preventive measures, including gonadal hormone replacement in females, should be initiated early after transplantation. Further studies are needed to identify patients at highest risk of bone loss and to monitor the effects of preventive therapy.

Absorptiometry, Photon↗

PubMed1995

Maternal aggression in rats: effects of olfactory bulbectomy, ZnSO4-induced anosmia, and vomeronasal organ removal.

Previous studies from our laboratory indicate that somatosensory inputs to the snout and ventral trunk, but not visual or auditory stimuli, play critical roles in the elicitation and maintenance of maternal aggression by lactating Norway rats toward a strange male intruder. There are conflicting reports on the influence of olfaction on maternal aggression. We explored the possible roles of central or peripheral anosmia on maternal aggression in Long-Evans rats during early lactation. In Experiment 1, responsiveness to both volatile and non-volatile odors was eliminated by bilateral olfactory bulbectomy (BOB), carried out during mid-gestation. BOB resulted in a reduced likelihood and intensity of maternal aggression on days 1 and 5 of lactation (L1 and L5), but also severe deficiencies in maternal behavior and litter growth and survival. In Experiment 2, anosmia to volatile odors was induced by spraying zinc sulfate intranasally on gestation day 21 and L1. This treatment had little or no effect on maternal aggression on L1 or L2 or on maternal behavior, especially if there was a 1-day recovery between the second treatment and testing. In Experiment 3, responsiveness to non-volatile odors was eliminated by vomeronasal-organ removal (VNX) carried out prior to mating. VNX did not disturb maternal behavior on L2-L8 or maternal aggression on L1 or L5. These results and others suggest that the expression of maternal aggression is affected by volatile odors, mediated possibly by accessory chemosensory systems such as the septal organ, or by neural changes that follow olfactory deafferentation, or both.

Aggression↗

PubMed1994

Maternal aggression in rats: effects of visual or auditory deprivation of the mother and dyadic pattern of ultrasonic vocalizations.

Previous studies indicate that somatosensory inputs to the snout and the ventral trunk play critical roles in the elicitation and maintenance of maternal aggression by postpartum lactating Long-Evans Norway rats toward a strange male intruder. In the present studies we examined the possible influence of visual and auditory stimuli in the display of this behavior. In Experiment 1, dams temporarily deprived of visual or auditory input by eyelid suturing or ear molds, respectively, on Day 2 postpartum, were found to have normal levels of maternal aggression 1 day later. In Experiment 2, males were found to contribute about 50% of the short-duration 50-kHz vocalizations, which begin shortly after introduction of the intruder, and all of the long-duration 22-kHz vocalizations, which begin after the onset of attacks. Nonetheless, females tested with males surgically devocalized 7 days earlier were not significantly different in aggressiveness from dams tested with vocalizing males on either Day 1 or Day 4 postpartum. These findings indicate that visual or auditory inputs from the pups or intruder are not critical to the display of maternal aggression in rats, at least within the confines of laboratory housing.

Aggression↗

PubMed1994

Alterations of the cortical representation of the rat ventrum induced by nursing behavior.

The representation of the surfaces of the trunk was mapped in detail in a series of anesthetized adult female rats to assess cortical representational changes that might be induced in the SI cortical field by a major natural source of a differentially heavy schedule of tactile inputs: the stimulation of the rat ventrum in nursing behavior. Controls included virgin rats and postpartum age-matched rats whose litters were removed on the day of birth. The SI representation of the ventral trunk skin of lactating rats was about 1.6 x larger than in matched postpartum nonlactating or virgin controls. The greatest representational change--about twofold--was for the nipple-bearing skin between the forelimbs and hindlimbs. Indeed, changes in SI representational territory for the middle third of the ventrum, a skin zone without nipples, were not significant. As a rule, the representation of the ventrum skin in lactating rats was at least as topographically ordered as was that reconstructed for nonlactating postpartum and virgin controls. Receptive fields (RFs) representing the ventrum skin in lactating females were about one-third the sizes of those recorded in matched nonlactating or virgin controls. RF size differences were again greater for the representation of the nipple-bearing skin in the anterior and posterior thirds of the ventrum than for the central third. Changes in RF sizes were roughly inversely related to changes in the cortical magnification of representation of the ventrum on the proportion of about 3:2. Interestingly, the glabrous nipple and areolar skin were only weakly represented--or not demonstrably represented--in the SI map of either lactating or control rats. These results indicate that there is a largely unstudied cortical neurology of nursing behavior. Major CNS changes are induced by this dramatic, episodic change in behaviorally important tactile inputs. In turn, input-induced changes presumably contribute to this emergent, rapidly evolving behavior.

Animals↗

PubMed1993

Maternal aggression of rats is impaired by cutaneous anesthesia of the ventral trunk, but not by nipple removal.

Aggression toward conspecific and allospecific individuals by female mammals is much more likely during lactation than during other reproductive states, a behavior that serves to protect the young. Previous research revealed that removal of nipples (thelectomy) prepartum greatly reduces the likelihood of postpartum aggression in house mice, but not in Sprague-Dawley Norway rats. The present work shows that prepartum thelectomy has no effect on the likelihood or intensity of postpartum aggression toward a strange male intruder in Long-Evans rats. In contrast, anesthesia of each nipple and surrounding skin prevents or severely impairs the elicitation of biting and attacking by the intruder, but does not impair normal retrieval of pups. Following removal of the litter, maternal aggression occurs readily at 1 h and somewhat less so at 5 h, but is absent at 24 h. These data suggest that while maternal aggression in postpartum rats does not require suckling, it is dependent on somatosensory stimulation of the ventral trunk by pups; this stimulation apparently produces a motivational change that lasts several hours.

Aggression↗

PubMed1992

Somatosensory control of the onset and retention of maternal responsiveness in primiparous Sprague-Dawley rats.

The role of perioral and ventral-trunk somatosensory stimulation from pups mediating the initial expression of maternal behavior and its long-term retention 8 days later, was investigated. Six groups of female rats were permitted to physically interact with four 1-5-day-old foster pups for 1 h, 36 h after Cesarean delivery on gestation day 21. Prior to this maternal experience, dams were subjected to: reduced cutaneous rostral snout sensitivity (anaptia) by injection of lidocaine into the mystacial pads; reduced ventral-trunk sensations by occlusion of the entire ventrum with a full spandex jacket; both manipulations; or control manipulations. Additional groups of females not receiving a maternal experience (inexperienced) also received the somatosensory deprivation or control manipulations. During retention testing, rats in the singly manipulated experienced groups exhibited reduced latencies to become maternal in comparison to their inexperienced counterparts (approximately 3 days vs. 8 days). However, rats previously rendered both anaptic and ventrally-occluded responded like inexperienced rats in showing a long latency to become maternal (8 days). Thus, reduction of either perioral or ventral somatosensory contact from pups did not block the maternal experience effect, but reduction of both of these inputs did.

Animals↗

PubMed1991

Nursing posture is elicited rapidly in maternally naive, haloperidol-treated female and male rats in response to ventral trunk stimulation from active pups.

Maternal responsiveness in rats can be induced in virgin females and males, without hormonal priming, following several days of cohabitation with pups. Because antagonism of dopamine (DA) facilitates nursing behavior in lactating rats, the response of nonlactating, maternally naive rats to effective stimulation of the ventral trunk (ventrum) from pups following similar treatment was investigated. Lactating dams, virgin females and males, both intact and gonadectomized, were treated with a catalepsy-inducing dose of haloperidol (5 mg/kg), a DA receptor antagonist, and tested with hungry pups 1 hr later. Subjects were placed over 8 pups and postures assessed every 3 min for 30 min. The nursing posture occurred in most subjects. Lactating and nonlactating females were similar in occurrence of the nursing crouch, though the intensity was somewhat higher in the former; females scored higher than males in terms of likelihood and intensity of crouching; and there was no effect of gonadectomy. The nursing posture was not elicited in intact virgin females if the stimulus pups were anesthetized or if the subjects were treated with saline instead of haloperidol. There were no sex differences in onset or intensity of catalepsy in response to the dose of haloperidol used. These results suggest that the nursing posture occurs reflexively, is not directly dependent upon ovarian hormones, and is diminished by the effects of androgens, prior and current.

Animals↗