Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “LORDOSIS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 973 records · Page 54Linked to original sources
PubMed2002

Acute fasting decreases sexual receptivity and neural estrogen receptor-alpha in female rats.

Acute food deprivation or chronic food restriction suppresses reproduction in female mammals. Although a link between undernutrition and ovarian function is well established in rats, a similar link with reproductive behavior in this species is yet to be described. Therefore, we compared the display of estrous behaviors induced by exogenous steroid hormone treatment in ovariectomized fed and fasted rats. In addition, estrogen receptor-alpha immunoreactivity (ERIR) was measured in fed and fasted animals to determine whether changes in behavior were associated with changes in the number of detectable ERIR-containing cells in several brain regions. Fasting for 74 h decreased lordosis quotients (LQ) and lordosis ratings (LR) in ovariectomized, steroid-primed rats. The number of detectable ERIR cells decreased after a 74-h fast in the mid-region of the arcuate (ARC), paraventricular (PVN) and ventromedial nuclei of the hypothalamus (VMH) and the ventral bed nucleus of the stria terminalis (BST) but did not change in a number of other areas examined. Taken together, these data demonstrate that, similar to the effect on the reproductive-endocrine axis, food deprivation for 74 h suppresses steroid-induced display of lordosis in adult, female rats. Furthermore, this suppression in sexual receptivity is associated with a decrease in ERIR in a number of areas, including the VMH, a region of the hypothalamus known to be critical for the display of reproductive behaviors in female rats.

Animals↗
PubMed2005

[Sagittal balance of the spine and degenerative spondylolisthesis].

PURPOSE OF THE STUDY: Several reports have examined the pathophysiology of degenerative spondylolisthesis. Very little work has however been devoted to the influence of spinal balance in the sagittal plane in its pathogenesis. The purpose of this work was to present a descriptive analysis of pelvic and spinal sagittal balance in a cohort of seventy patients treated for degenerative spondylolisthesis and to compare findings with those established in a population of 250 volunteers. The goal was to deduct pathophysiological hypotheses and identify therapeutic implications. MATERIAL AND METHODS: Seventy patients were included in this study. The following variables were noted: pelvic incidence and version, sacral slope, lumbar lordosis, thoracic kyphosis, T9 sagittal tilt and S1-S2 angle. These variables were measured on digitalized lateral views of the spine using a dedicated software (SpineView). Univariate analysis of the values obtained was performed to identify the variable distributions. Multivariate analysis was applied to study the relationships between these variables and to better define perturbations of spinal balance in the anteroposterior plane. The findings were compared with those obtained in a control population. RESULTS: One of the essential characteristics of the cohort of patients with degenerative spondylolisthesis was the presence of an exaggerated pelvic incidence (62.6 degrees versus 54.7 degrees in the control population). The most significant determinants of T9 sagittal tilt (which reflects sagittal balance) were: pelvic version, pelvic incidence, lumbar lordosis, and L4-S1 local lordosis. One-third of our patients presented posterior tilt due to exaggerated thoracic kyphosis. The high pelvic incidence, via hyperlordosis and increased pelvic version, could be one of the factors favoring degenerative disease of the spinal unit. CONCLUSIONS: This work enabled us to better describe sagittal balance in patients with degenerative spondylolisthesis and to propose hypotheses concerning the underlying mechanism of progressive degeneration. We emphasize the diversity of spinal balance in these patients and the different therapeutic implications.

Aged↗
PubMed2002

Hormonal and genetic influences on arousal--sexual and otherwise.

Genetic influences on lordosis, a mammalian social behavior, are amenable for study because of the relative simplicity of both stimuli and response. The neural circuit for lordosis involves a supraspinal loop, which is controlled by an estrogen- and progesterone-dependent signal from the medial hypothalamus and results in heightened sexual motivation. In turn, this involves elevated states of arousal, defined by increased sensory alertness, motor activity and emotional reactivity. Mice in which the gene encoding the alpha form of the estrogen receptor (ERalpha) has been knocked out show that ERalpha is crucial for lordosis behavior. Comparing ERalpha-, ERbeta- and double knockouts reveals that different patterns of sexual behaviors in mice require different patterns of ER activity. Understanding how hormonal and genetic effects on deep motivational and arousal processes contribute to their effects on specific sexual and aggressive behaviors pose significant challenges for mouse functional genomics.

Animals↗
PubMed1992

Hippocampal electrical activity in the female rat: the estrous cycle, copulation, parturition, and pup retrieval.

Hippocampal electrical activity was examined in female rats across the four phases of the estrous cycle, as well as during copulation, parturition, and pup retrieval. Possible hormonal effects on hippocampal activity were examined by recording daily during struggling and immobility throughout five estrous cycles. No differences in the characteristics of rhythmical slow activity (RSA), large-amplitude irregular activity (LIA), or their relation to behavior were found between the phases of the estrous cycle. Behaviors examined during copulation were lordosis, hopping, and ear wiggling. Lordosis and ear wiggling were both accompanied by irregular waves, with some low frequency RSA also present during lordosis. Hopping was accompanied by RSA which was greater in amplitude and frequency than RSA during walking. Parturition behaviors examined included body extensions, genital or pup licking, and 'body flattening'. Body extensions were found to be associated with irregular hippocampal activity, and appeared to be a Type 2 behavior. Interestingly, sudden suppressions of the hippocampal record lasting 1-5 s often preceded body extensions. Irregular hippocampal activity was present at all times during genital and pup licking. Body flattening was typically accompanied by very high amplitude irregular waves which, although the rats were awake, resembled a sleeping hippocampal pattern. Pup retrieval involved walking and was thus always accompanied by RSA.

Animals↗
PubMed1999

Hormonal integration of neurochemical and sensory signals governing female reproductive behavior.

This review focuses on findings from our laboratory regarding mechanisms by which the ovarian steroid hormones, estradiol (E2) and progesterone (P), act in the hypothalamus (HYP) to regulate the expression of lordosis, an important component of female reproductive behavior in rats and many other species. The first section summarizes recent work suggesting that cGMP, perhaps via P-receptor activation, may be an intracellular mediator of the facilitatory actions of a variety of hormones and neurotransmitters on lordosis behavior in E2-primed rats. In the second section, we focus on E2 and P regulation of norepinephrine (NE) neurotransmission in the HYP. We review evidence that ovarian hormones act both peripherally and centrally to determine whether NE is released in the HYP in response to copulatory stimuli. We also suggest that the steroid milieu determines the cellular responses of hypothalamic neurons to released NE, favoring the activation of pathways implicated in the facilitation of both lordosis behavior and the preovulatory gonadotropin surge. It is likely that E2 and P have similar actions on other neurotransmitter and neuromodulator systems, thereby maximizing the probability that females are sexually receptive during the periovulatory period.

Animals↗
PubMed2001

Estrogen and endogenous opioids regulate CCK in reproductive circuits.

This review focuses on the interaction of estrogen with the cholecystokinin (CCK) and endogenous opioid peptide systems in the medial preoptic nucleus, and how these interactions result in alterations of a stereotypic female reproductive behavior--lordosis. The medial preoptic nucleus is an integral part of a circuit controlling lordosis that extends from the limbic system through the hypothalamus. Estrogen alters the integration of sensory information in the circuit that results in the display of sexually receptive behavior. Estrogen determines the activity of CCK and endogenous opioid peptide systems through regulation of expression, release and interaction with specific receptors. Studies of each system individually have indicated that they are pivotal to the expression of lordosis. Recent studies demonstrate an estrogen-dependent interaction between endogenous opioid and CCK systems that control reproductive behavior.

Animals↗
PubMedDate not supplied

Mid-term clinical results of Graf stabilization for lumbar degenerative pathologies. a minimum 2-year follow-up.

BACKGROUND CONTEXT: Spinal fusion has some adverse effects, such as nonunion and pain at the site of grafted bone, and fusion with rigid spinal instrumentation especially may have the possibility of increasing mechanical stress on the segments adjacent to the site of fusion. The theory of the Graf system is that it will decrease adjacent disc deterioration because of maintenance of regional lordosis with flexibility and restriction of the motion of unstable segments without rigid spinal fusion. PURPOSE: To assess the clinical and radiologic results of Graf stabilization for lumbar degenerative disorders with minimal or mild instability. STUDY DESIGN: This is a retrospective study examining the mid-term results of Graf stabilization. PATIENT SAMPLE: In total, 59 patients underwent Graf ligamentoplasty and adequate decompression from April 1993 to September 1997. The subjects were 30 men and 29 women, and the mean age at the time of surgery was 60.6 years, ranging from 23 to 82 years. The average follow-up period was 3 years and 5 months, ranging from 2 years to 5 years and 10 months. OUTCOME MEASURES: We evaluated the surgical results using a scoring system, a visual analog scale, and radiological measurements. METHODS: The results were assessed according to a clinical scoring system established by the Japanese Orthopaedic Association (JOA score) and ratings based on a visual analog scale. Through analysis of x-ray images, the sagittal alignment (regional lordosis) and the range of motion (ROM) of the stabilized segments were measured in all cases, and the percentage of segments slipping and posterior disc height were determined for 29 patients with degenerative spondylolisthesis. RESULTS: Clinical scores and low back pain ratings based on a visual analog scale were significantly improved at the time of final follow-up compared with the preoperative values. Regional alignment of the operative segments was maintained in lordosis at the time of final follow-up. Preoperative ROM was significantly reduced at the time of final follow-up. There were no statistical differences in percentage of slippage or percentage of posterior disc height between the final follow-up values and the preoperative values. CONCLUSIONS: Our clinical results indicate that the Graf system is a suitable treatment option for mild and early lumbar degenerative diseases with minimum flexion instability of less than 10 degrees.

Adult↗
PubMed1986

Evidence for involvement of midbrain central gray in cholinergic mediation of female sexual receptivity in rats.

Experiments were designed to determine the role of the midbrain central gray (MCG) in facilitation of lordosis by cholinergic agonists. In Experiment 1, estradiol-treated female rats received microinjections of carbachol into the MCG and showed a dose-related behavioral facilitation to the agonist. In Experiment 2, MCG injections of oxotremorine (OXO), a selective muscarinic receptor agonist, yielded a dose-related facilitation; this was blocked by systemic pretreatment with scopolamine (SCOP), a muscarinic antagonist. In Experiment 3, MCG-lesion animals were injected unilaterally with OXO intraventricularly following contralateral injection of SCOP or vehicle. Females with MCG damage displayed significantly less facilitation than sham-lesion animals. Pretreatment with SCOP abolished lordosis facilitation in both groups. In addition, after treatment with estradiol and progesterone, sham-lesion females showed more receptivity than MCG-lesion females. Systemic injection of SCOP produced a significant decline in lordosis for both groups. On the basis of these data, it is suggested that the MCG plays an important role in the cholinergic mediation of female sexual receptivity.

Animals↗
PubMed1993

Effects of a muscarinic antagonist on various components of female sexual behavior in the rat.

The effects of the muscarinic antagonist scopolamine on lordosis, solicitation, pacing, approach, attractivity, and activity were evaluated in ovariectomized rats brought into sexual receptivity with estrogen and progesterone. Systemic (1 mg/rat) or intraventricular (10 micrograms bilaterally) administration of scopolamine significantly reduced the incidence of lordosis and solicitation behaviors and disrupted typical pacing of sexual contacts with a stimulus male. In addition, females avoided contact with a stimulus male, but not a stimulus female, following intraventricular infusion of scopolamine. The levels of general activity and frequencies of sexual contacts were similar in females treated intraventricularly with scopolamine and vehicle solutions. Consequently, scopolamine disrupted various components of sexual behavior, including lordosis, solicitation, pacing, and approach, without altering female attractivity or general activity.

Animals↗
PubMed1990

Receptivity of the female rat (Rattus norvegicus) after male devocalization: a ventral perspective.

Male rats (Rattus norvegicus) emit at least two patterns of vocalization during copulation, the mating call and the pre-ejaculatory call. Both calls promote immobility of the female during lordosis, but the pre-ejaculatory calls are more effective. We undertook, through ventral observations of the mating pair, to determine if the female failed to assume or maintain the lordosis posture when mounted by a devocalized male and also to determine if the devocalized male was providing adequate stimulation to induce receptive behavior. Females were more likely to move away from the devocalized males before assuming the full lordosis posture. Furthermore, they were more likely to move away before the males had a chance to engage in intromissive behavior. However, when the females remained immobile long enough for the males to achieve a mount or intromission, there was little difference in the behavior of either animal that resulted from the devocalization of the male.

Animals↗
PubMed1975

Female lordotic behavior mediated by monoamines in male rats.

Direct application of serotonergic of beta-adrenergic receptor blockers to anterior or posterior areas of the hypothalamus induced lordosis in intact estrogen-primed male rats. Such treatment with an alpha-adrenergic blocker or systemic administration of progesterone failed to increase lordosis. Centrally elicited lordosis did not occur without estrogen priming. Anatomical and neurochemical similarity may exist in the brain mechanism mediating lordotic behavior in male and female adult rats.

Adrenergic beta-Antagonists↗
PubMed1975

Neonatal androgenic stimulation and adult sexual behavior in male and female golden hamsters.

Neonatally and adult castrated male hamsters as well as neonatally androgenized and nonandrogenized female hamsters were tested for both mounting and lordosis behaviors during treatment with either testosterone or ovarian hormones. Neonatal androgenization facilitated mounting behavior in adult animals administered either testosterone or ovarian hormones and suppressed lordosis behavior in adult ovarian-hormone-treated animals. Early androgen effects on the display of lordosis behavior during adult testosterone treatment were complex and varied with the exact timing of perinatal endogenous or exogenous androgenization. Species differences in hormone-behavior relationships and the possible role of perinatal androgenization in the development of rodents' ability to aromatize androgens were discussed.

Age Factors↗
PubMed1979

Prelordotic behavior in the hamster: a hormonally modulated transition from aggression to sexual receptivity.

The behavioral responses of the female golden hamster to a sexually experienced male were analyzed as a function of the stage of the female's estrous cycle. Exogenous estradiol or estradiol followed by progesterone was given to ovariectomized females to determine the role of these hormones in the regulation of cyclic changes in the female's response to the male. Females were paired on a daily basis with sexually active males for 10 min, and behavioral interactions were recorded. Significantly more fighting occurred during early diestrus than later in the cycle. During the 24 hr preceding sexual receptivity, fighting was infrequent. BY 8 HR PRIOR TO THE ONSET OF SEXUAL RECEPTIVITY, 86% OF THE POPULATION EXHIBITED A BEHAVIOR RESEMBLING THE ONSET OF LORDOSIS WITHOUT IMMOBILIZATION (PRELORDOSIS). Following ovariectomy fighting was at a high level (80%--90%). Estradiol replacement, over a 28-day test period, resulted in a significant decrease in aggression and a significant increase in the display of the prelordotic response without inducing lordosis. Initially, the treatment with progesterone following 7 days of estradiol treatment caused the female to display lordosis. After 24 hr a significant increase in aggression, which continued as long as progesterone was present, was observed. After removal of progesterone a significant decrease in aggression occurred. Thus, estradiol causes the female to become tolerant of the male's approach, the female exhibiting prelordosis in response to the male's investigation. Estradiol and progesterone are necessary for normal sexual receptivity; however, after 24 hr, estrogen-progesterone-treated females become agonistic to the male.

Aggression↗
PubMedDate not supplied

Mechanical effects of leg position on vertebral structures examined by magnetic resonance imaging.

BACKGROUND AND OBJECTIVES: Leg manipulation has been postulated to affect spinal curvature and position of the cauda equina within the dural sac. However, no evidence of such mechanical effects has been shown in living subjects. We used magnetic resonance imaging to evaluate the mechanical effects of leg position on these 2 parameters. METHODS: Sagittal and axial magnetic resonance images of the lumbosacral vertebral canal were obtained in 5 healthy, female volunteers with the subject in the supine position with knees straight, knees slightly flexed, and knees fully flexed. RESULTS: In the straight leg position, physiologic lumbar lordosis was evident in all subjects on midline sagittal slices, whereas lumbar lordosis disappeared in the fully flexed leg position. On the axial slices the cauda equina moved ventrally within the dural sac in all subjects in the fully flexed leg position. In 1 of the 5 subjects the cauda equina moved ventrally and also separated completely into right and left parts. CONCLUSIONS: Our findings indicate that 2 potential factors, flattening of the lumbar lordosis and some added tension on the lumbosacral nerve roots, may contribute to postoperative back and leg aching after spinal anesthesia in the lithotomy position.

Adult↗
PubMedDate not supplied

The role of melanocortin receptors in sexual behavior in female rats.

Earlier data have indicated that alpha-MSH may play a role for sexual behavior in rats. In this study we investigated the effects of MSH peptides on sexual receptivity in ovariectomized-adrenalectomized female rats, pre-treated with benzoate of estradiol, in presence of vigorous male rats. The results show that alpha-MSH significantly increases lordosis behavior in female rats after injections into the ventromedial nucleus. Interestingly, we have for the first time shown that gamma-MSH also causes significant increase in lordosis in female rats. Furthermore, we show that HS014, an antagonist for the central MC receptors, in dose dependent manner blocks the effect of alpha-MSH on lordosis. The results indicate that the effects of MSH peptides on female sexual behaviour are mediated through a specific MC receptor, which could be the MC3 receptor.

Adrenalectomy↗
PubMed1991

Influence of neurotransmitters on sexual differentiation of brain structure and function.

Newborn rats received daily subcutaneous treatment with compounds which influence serotoninergic, cholinergic, alpha-adrenergic and beta-adrenergic activity. In adulthood luteinizing hormone (LH) secretion pattern, female sexual behavior, and the volume of the sexually dimorphic nucleus of the preoptic are (SDN-POA) were determined. Postnatal administration of l-tryptophan increased the volume of the SDN-POA significantly when given alone or when given simultaneously with testosterone propionate (TP). Para-chlorophenyl-alanine (pCPA) also increased SDN-POA volume, but did not potentiate the stimulating influence of TP. Clonidine had no effect per se on SDN-POA development, but it significantly potentiated the effect of TP in females. Salbutamol increased SDN-POA volume in females and in males. Postnatal treatment of female rats with the alpha-adrenergic receptor antagonists prazosine and yohimbine or with the nicotin receptor antagonist mecamylamine had permanent potentiating effects on the pattern of LH secretion, whereas postnatal treatment with beta-adrenergic compounds reduced the LH-release response to gonadal steroids in adulthood. Postnatal treatment with clonidin or l-tryptophane inhibited differentiation of the capacity for lordosis behavior. Beta-receptor agonists postnatally had a potentiating effect on the capacity for lordosis behavior in female and male rats. Cholinergic stimulation postnatally inhibited differentiation of the capacity for lordosis behavior in female rats, but prevented the inhibitory effect of postnatal androgenization. There was no correlation between SDN-POA volume and any of the two functional parameters.

Animals↗
PubMedDate not supplied

[Effect of posterior lumbar interbody fusion on the lumbar sagittal spinal profile].

AIM: To determine the effect of different cage geometries and posterior instrumentation on the sagittal spinal profile after monosegmental lumbar interbody fusion. METHOD: The study is based on a retrospective analysis of 119 patients with segmental instability, who were surgically managed by monosegmental PLIF with PEEK-Cages and dorsal instrumentation. RESULTS: At radiographic follow-up after surgery we found a significant improvement of the lumbar sagittal spinal profile, independent of the cage geometry utilised. A marked discrepancy between 0 degrees -standard and 4 degrees -trapezoid implants concerning the radiographic parameters lumbar lordosis, disc height, correction of spondylolisthesis and sacral inclination was not found. With the use of 4 degrees optimised cages in segment L4/5 slightly better results for segmental lordosis were obtained. Reliability of the radiographic evaluation, expressed as intra-observer error, was satisfactory. Cage geometry did not have an effect on the clinical result. By combining interbody fusion with pedicular instrumentation the reposition of slipped vertebra and distraction of the interbody space could more effectively be achieved. Patients without dorsal instrumentation had a higher rate of pseudarthrosis as well as a less satisfactory clinical outcome. CONCLUSION: These results show that normal sagittal alignment after single-level lumbar fusion can be achieved with rectangular and 4 degrees -wedged cages. Although results after utilization of 4 degrees -wedged cages do not significantly differ, these implants offer the surgeon one more sizing variation with which physiological lumbar lordosis may be attained. The combination of intersomatic implants with dorsal instrumentation achieves a more precise realignment and has a lower rate of cage-associated complications. It therefore seems prudent that an interbody fusion for the surgical management of lumbar segmental instability should be combined with pedicular instrumentation.

Equipment Failure Analysis↗
PubMed2000

Abnormal spinal curvature and its relationship to pelvic organ prolapse.

OBJECTIVE: Intra-abdominal vector forces have been implicated in the development of genital prolapse. Because the normal spinal curvature appears to protect the pelvic cavity from direct upper abdominal forces, variations in spinal curvature may alter these vector forces and possibly potentiate the development of pelvic organ prolapse. This study was undertaken to evaluate the relationship of spinal curvature and pelvic organ prolapse, specifically, the loss of lumbar lordosis or pronounced thoracic kyphosis. STUDY DESIGN: A total of 363 patients referred for various complaints of urinary incontinence or pelvic organ prolapse were included in this multicenter, prospective, case-control study. All patients underwent a detailed history with site-specific examinations; pelvic organ prolapse was quantitatively assessed according to the POPQ (pelvic organ prolapse quantitation) staging system. Spinal curvature was measured with a flexi-curve malleable rod when patients were in a fully erect position. Spinal curvature was then transferred to graph paper by tracing the flexi-curve. Thoracic and lumbar curvatures were determined by measuring thoracic and lumbar lengths and widths, respectively. RESULTS: Ninety-two patients had abnormal spinal curvature according to the study criteria. Complete loss of lumbar lordosis was found in 69 patients. Of the 92 patients with an abnormal curvature, 84 currently had or previously had pelvic organ prolapse (sensitivity, 91%). When compared with patients with a normal curvature, patients with an abnormal spinal curvature were 3. 2 times more likely to have development of pelvic organ prolapse (odds ratio, 3.18; 95% confidence interval, 1.46 to 6.93; P =.002). There was no difference in the number of vaginal deliveries, weight of largest vaginally delivered infant, or body mass index. Only 11% (8/72) of patients with stage 0 prolapse had an abnormal spinal curvature, which increased to 30% (28/99) in patients with stage III prolapse (P =.042). CONCLUSION: An abnormal change in spinal curvature, specifically, a loss of lumbar lordosis, appears to be a significant risk factor in the development of pelvic organ prolapse.

Adult↗