Biomedical subjects

B Larsson

Publications and source records attributed to B Larsson.

At least 37 records · Page 2Linked to original sources

PubMed2001

Predicting transmembrane protein topology with a hidden Markov model: application to complete genomes.

We describe and validate a new membrane protein topology prediction method, TMHMM, based on a hidden Markov model. We present a detailed analysis of TMHMM's performance, and show that it correctly predicts 97-98 % of the transmembrane helices. Additionally, TMHMM can discriminate between soluble and membrane proteins with both specificity and sensitivity better than 99 %, although the accuracy drops when signal peptides are present. This high degree of accuracy allowed us to predict reliably integral membrane proteins in a large collection of genomes. Based on these predictions, we estimate that 20-30 % of all genes in most genomes encode membrane proteins, which is in agreement with previous estimates. We further discovered that proteins with N(in)-C(in) topologies are strongly preferred in all examined organisms, except Caenorhabditis elegans, where the large number of 7TM receptors increases the counts for N(out)-C(in) topologies. We discuss the possible relevance of this finding for our understanding of membrane protein assembly mechanisms. A TMHMM prediction service is available at http://www.cbs.dtu.dk/services/TMHMM/.

Animals↗

PubMed2001

Nitric oxide participates in prick test and irritant patch test reactions in human skin.

The aim of this study was to investigate the involvement of nitric oxide (NO) in the modulation of immediate and delayed immunological and nonimmunological reactions in human skin. The NO donor nitroglycerin, 0.1 microgram, and the NO synthase inhibitor, NG-nitro-L-arginine (L-NAME), 0.1 microgram, were injected intracutaneously prior to provocation tests. The following provocation tests were carried out: 8 patients with pollen allergy to birch were provoked by a prick test with the allergen and the volume of the weals was measured; 20 patients with allergy to nickel were provoked with nickel sulfate epicutaneously; and 26 healthy volunteers were provoked with tuberculin (causing delayed immunologic reaction), benzalkonium chloride (irritant contact dermatitis), UV radiation or benzoic acid (nonimmunological contact urticaria). The test reactions were evaluated by planimetry. L-NAME inhibited irritant contact dermatitis (P = 0.020) but augmented immediate immunological reactions (prick test) (P = 0.016). The other test reactions remained unchanged. Nitroglycerin did not affect any of the reactions significantly. The results suggest that NO is involved in immediate immunological reactions and irritant contact dermatitis.

Adult↗

PubMed2001

Fibre type proportion and fibre size in trapezius muscle biopsies from cleaners with and without myalgia and its correlation with ragged red fibres, cytochrome-c-oxidase-negative fibres, biomechanical output, perception of fatigue, and surface electromyography during repetitive forward flexions.

In the literature enlarged/increased cross-sectional area (CSA) of type I muscle fibres has been reported as a morphological mark of work-related localised myalgia in the descending part of the trapezius muscle of women. These studies did not use enough subjects or lacked an adequate control group. The recording of surface electromyograms (EMG) is central to the research field of work-related myalgia. However, the influence of intrinsic muscle properties such as the effect of muscle fibre distribution upon surface EMG has to be better understood in order properly to evaluate this method as a possible diagnostic and preventive tool. This study had two aims. Firstly, it investigated the muscle fibre distribution and CSA in work-related myalgia in trapezius muscles. Secondly, the multivariate relationships among muscle morphology and histochemistry [ragged-red (RR) fibres, and cytochrome-c-oxidase-negative-fibre changes] EMG, perceived fatigue, and biomechanical output of shoulder flexions were analysed. The raw data have been presented in an earlier study. The participants in this study were 25 female cleaners with work-related myalgia of the trapezius muscle and 25 female cleaners not experiencing work-related myalgia of this muscle. The control group comprised 21 healthy female teachers who had not been exposed to highly repetitive work or static muscle work. Smaller CSA of type II fibres were found in cleaners compared to teachers. In this study the CSA of type I fibres of the trapezius muscles associated with myalgia were no greater than in muscles without myalgia. The prevalence of RR fibres together with age, fibre type proportions, CSA and working as a cleaner correlated with the ability to relax as recorded electromyographically. The relative mean frequency of the EMG of the trapezius muscle correlated with the prevalence of RR fibres, but it did not correlate with the proportions and CSA of different fibre types. Low biomechanical outputs and low signal amplitude increases of the EMG during the test were associated with high proportions of type -IIB fibres. The smaller CSA of type II fibres in cleaners might have reflected a different muscle activation pattern due to different occupational demands in cleaners than in teachers. Morphological or histopathological variables can influence the three EMG variables investigated.

Biomechanical Phenomena↗

PubMed2001

Detailed organization of nitric oxide synthase, vasopressin and oxytocin immunoreactive cell bodies in the supraoptic nucleus of the female rat.

The anatomical distribution and quantitative relations of cell bodies containing neuronal nitric oxide synthase (nNOS), 8-arginine vasopressin (AVP) and oxytocin (OT) were examined throughout the supraoptic nucleus (SON) of the female rat by means of immunocytochemical and NADPH-diaphorase (NADPH-d) histochemical techniques using a triple labelling methodology. Seven chemically defined populations of neurons containing all combinations of either nNOS, AVP or OT were identified. nNOS-containing (NADPH-d positive) neurons, amounting to about 40% of all neurons counted, were most frequent in central and dorsal regions, and were evenly distributed along the rostro-caudal axis. Two small nNOS-positive neuronal populations were preferentially located dorso-centrally in the nucleus: nNOS-positive neurons containing both AVP- and OT-immunoreactivity, and neurons only containing nNOS. Slightly less than half of all nNOS-positive neurons contained AVP, and a similar share of nNOS-positive neurons contained OT. The occurrence of nNOS-positive/AVP-containing neurons was highest in the caudal half, whereas that of nNOS-positive/OT-neurons was highest in the rostral half of SON. The data demonstrate new findings concerning the anatomical organization and co-localization patterns of nNOS-, AVP- and OT-containing neuronal populations in SON. We conclude that the absolute and relative occurrence of the identified neuronal populations vary markedly in different parts of SON. This is important to take into consideration when performing, and evaluating experimental investigations concerned with neurochemical changes in SON.

Animals↗

PubMed2001

Depressive symptoms among young Norwegian adolescents as measured by the Mood and Feelings Questionnaire (MFQ).

In a stratified random and representative sample of 2,560 13- to 14-year-old Norwegian girls and boys, depressive symptoms were assessed by means of the Mood and Feelings Questionnaire (MFQ). The MFQ showed a good internal consistency (alpha), and test-retest correlations (r) for three-week and three-month intervals were 0.84 and 0.80 respectively. Convergent and discriminative validity were also assessed. The mean total MFQ score for the whole sample was 10.6 (SD 9.5). The results showed a significant sex by age interaction effect in that girls increased their mean total MFQ sum score by age while the boys' scores decreased slightly. Reports of unattractiveness, restlessness, indecisiveness and transient feelings of low mood were common in the total sample, while unhappiness, irritability, self-dislike and concentration problems were common among high-scoring subjects. Girls experienced more often lowered mood, were more concerned with their appearance and had more self-depreciatory notions than boys, while boys more often than girls had lower school satisfaction. Girls were preponderant among the high-scoring subjects. The results of logistic regression analyses showed that concentration problems were the strongest predictor of high scores. The findings are discussed in view of similar epidemiological studies in which DSM-IV criteria have been used in the assessment of depressive symptoms and disorders among adolescents.

Adolescent↗

PubMed2001

Self-reported competencies and problems among Swedish adolescents: a normative study of the YSR. Youth Self Report.

The aim of the study was to provide a standardisation of self-reported competencies and emotional/behavioural problems among Swedish adolescents, using the Youth Self-Report (YSR). The YSR was completed by 2522 adolescents aged 13-18 years, recruited from secondary and upper secondary schools in different regions in Sweden. The results showed that effects of gender and age were small but significant with girls scoring higher than boys on most problem scales, and 15- to 16-year-olds scoring higher than younger and older adolescents on the problem scales. Small effects were also found for residence as well as for parental SES. The correlations between internalising and externalising problems were 0.51 for boys and 0.49 for girls, whereas the correlation between competence and problem scores was low. We conclude that the individual variation in YSR-scores is much greater than can be attributed to factors such as gender, age, SES, or residential area. Consequently, the YSR has the potential to serve as an instrument for assessing individual adolescents' self-reported competencies and problems in Sweden. Given the almost orthogonal relation between self-reported competencies and problems, the competence scale is surprisingly little used in psychopathology research.

Adolescent↗

PubMed2001

The role of human papillomavirus in cervical adenocarcinoma carcinogenesis.

Human papillomavirus (HPV) is considered the single most important co-factor in the development of cervical squamous cell carcinomas. Adenocarcinomas of the cervix are also related to HPV, but the correlation is reported to be less pronounced. In the present study, 131 cervical adenocarcinomas were identified through the Swedish Cancer Registry, examined morphologically and then analysed with sensitive polymerase chain reaction (PCR)-based HPV methods for a study of age-related prevalence of HPV. HPV was identified in 64% of the tumours after PCR amplification of the HPV L1 gene only and in 71% following PCR amplification of both the L1 and E6 genes of HPV. HPV 18 was the most prevalent (52%), followed by HPV 16 (33%) and other types of HPV (15%). The prevalence of HPV was shown to be age-dependent. In women younger than 40 years, HPV was present in 89%, whereas in women 60 years and older, HPV was observed in only 43%. The difference was statistically significant, P<0.005. The HPV-positive adenocarcinomas were represented by an age distribution similar to that of cervical squamous carcinomas with a maximum age, in the 40-49 year old group, whereas the frequency of HPV-negative adenocarcinomas increased with age, typical of most carcinomas occurring in elderly women.

Adenocarcinoma↗

PubMed2001

Effects of repeated follicular punctures on ovarian morphology and endocrine parameters in dairy heifers.

Three experimental and three control heifers were included in the study. After a control period (CP), the experimental heifers were subjected to 4 and 5 weeks of twice-weekly follicular punctures (FPP1 and FPP2) with two oestrous cycles in between. The follicular punctures were performed using the ovum pick-up (OPU) technique. During the CP and FPPs, ovarian activity was monitored by transrectal ultrasonography and analyses of plasma progesterone, prostaglandin F2alpha (PGF2alpha) metabolite, luteinizing hormone (LH), oestradiol and follicle stimulating hormone (FSH) levels. The animals were slaughtered 7 days after cessation of FPP2 and their ovaries examined. The control animals were monitored for their oestrous cyclicity and were then ovariectomized and the ovaries examined. Despite the absence of ovulation, the formation of corpus luteum (CL)-like structures could be ultrasonographically observed during FPPs. These structures either had characteristics comparable to those of the CLs during the CP (group 1) or were smaller and had a shorter life span and (or) luteal active phase with a lower progesterone production (group 2). In group 1, CL-like structures emanated from punctures of large-sized follicles on or close to the days on which the animals showed oestrus and had a rise in oestradiol and LH. In group 2, the structures developed from punctures of smaller-sized follicles and no oestrus nor a detectable 1.14 rise was revealed around punctures. During most FPPs, the basal level of LH was at zero. During all FPPs, a significant rise in FSH level occurred on the day following the day of puncture. To conclude, repeated follicular puncture appeared to alter slightly endocrine profiles and cause minor morphological changes in the ovaries. Both the macro- and microscopic examinations revealed the presence of luteal structures and follicles of various sizes in the ovaries of all heifers studied. The connective tissue in the ovarian tunica albuginea of the experimental heifers was significantly thicker than that in controls (P < 0.001).

Animals↗

PubMed2001

Prediction of the oocyte recovery rate in the bitch.

In order to investigate the possibility of predicting the recovery rate of oocytes for use in a sperm-zona pellucida binding assay, ovaries were obtained from 67 bitches of 37 different breeds, and cumulus-oocyte complexes (COCs) were recovered by mincing the ovaries with a scalpel. The mean number of COCs recovered was 37.2 +/- 34.1 (range 0-145) per ovary. Age significantly affected COC recovery rates. From bitches 1-6 years old, 54.2 +/- 35.1 COCs/ovary were recovered, compared to 26.4 +/- 29.0 from bitches 7-13 years old (P = 0.003). The morphology of the uterus or the presence or absence of ovarian structures had no significant effect on COC recovery rates, although there was a tendency for more COCs to be recovered from ovaries with only follicles visible on the surface. There were no significant correlations between body weight or ovarian weight and COC recovery rates. There was a high correlation in the COC recovery rate between the two ovaries of a bitch, enabling an approximate estimation of the COC recovery rate from the second ovary when the COCs from the first ovary have been recovered. The large variation in COC recovery rates between bitches stresses the need for storage of canine oocytes in order to secure a high enough number of oocytes for a homologous sperm-zona pellucida binding assay in the dog.

Age Factors↗

PubMed2001

Combipolar sensing in dual chamber pacing: is there still a need for bipolar leads in the atrium?

Bipolar leads have been shown to provide superior sensing conditions compared to unipolar leads as bipolar sensing is less susceptible to interference. However, the mechanical long-term integrity and longevity of bipolar leads is inferior to that of unipolar leads. A prospective randomized, multicenter study was performed to investigate a new atrial detection configuration called combipolar sensing. This new sensing concept is designed for the use of conventional unipolar leads in the atrium and the ventricle. While the atrial stimulation is unipolar, atrial sensing is accomplished in a bipolar way using the ventricular lead tip as the indifferent electrode. A modified dual chamber pacemaker provided with this sensing concept was implanted in 26 patients. At predischarge and at the 1- and 3-month follow-ups no significant differences in atrial sensing thresholds and P wave amplitudes were found between the unipolar and the combipolar sensing configuration at rest or during provocation. Myopotential inhibition could be demonstrated in 22 patients during unipolar sensing at sensitivity settings as "low" as 2 mV. In contrast, during combipolar sensing it could only be demonstrated in one patient once and only at the highest atrial sensitivity of 0.5 mV. Combipolar atrial sensing is feasible under normal conditions and during provocation. Myopotential interference is negligible. Thus, combipolar sensing offers comparable atrial sensing to bipolar without the disadvantages of a bipolar lead.

Adolescent↗

PubMed2001

Escherichia coli-induced inducible nitric oxide synthase and cyclooxygenase expression in the mouse bladder and kidney.

BACKGROUND: The host response to urinary tract infection includes the production of different inflammatory mediators. We investigated the cellular localization and time course of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX-2) expression in the mouse bladder and kidney after bacterial infection. METHODS: Experimental urinary tract infection in mice was established by intravesical inoculation of a clinical uropathogen Escherichia coli (E. coli) AD 110. Urine was collected at 6-, 12-, 24-, and 72-hours postinstillation, and the nitrite concentration was determined. The induction of iNOS and COX-2 was studied by immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Nitrite levels in the urine had increased threefold at 6 and 12 hours postbacterial instillation. Bladders from mice instilled with AD 110, but not with phosphate-buffered saline, showed a large number of iNOS-- and COX-2--expressing inflammatory cells. The inflammatory cell activation peaked at 6 and 12 hours postinstillation and had vanished by 72 hours. iNOS expression was detected in some urothelial cells after 24 and 72 hours, but COX-2 expression was not detected. In the kidney, infection activated an iNOS and COX-2 response, as shown by immunoreactivity in inflammatory cells at all time points. A strong epithelial iNOS response was observed in the renal pelvis at 12, 24, and 72 hours postinstillation, but COX-2 was not detected. Enhanced tissue expression of iNOS and COX-2 after bacterial instillation was also demonstrated by RT-PCR. CONCLUSIONS: E. coli AD 110 induced expression of iNOS and COX-2 in the urinary tract. Inflammatory cells expressed both iNOS-and COX-2, but epithelial cells expressed only iNOS and with a later onset than in the inflammatory cells. This suggests that the epithelial iNOS response is not caused by direct bacterial activation, but more likely is by mediators involved in the inflammatory response.

Animals↗

PubMed2001

Does relaxation treatment have differential effects on migraine and tension-type headache in adolescents?

The present study evaluated the effects of relaxation treatment in 36 adolescents aged 13 to 18 years (mean +/- SD, 15.4 +/- 1.55 years) suffering from migraine or migraine and tension-type headache as compared with a waiting-list condition group. The subjects rated various characteristics of migraine and tension-type headache in a diary. Significant reductions were found for total headache sum (P <.05) and intensity scores of total headache activity (P <.05) as well as for migraine intensity (P <.05) for subjects treated with relaxation as compared with those in the waiting-list condition group. However, no significant differences between the two groups were found for tension-type headache. Fifty percent of the adolescents treated with relaxation training attained a clinically significant improvement, compared with 12% of those in the waiting-list condition. It is suggested that treatment goals for migraine and migraine occurring with tension-type headache might be different and that relaxation training also might benefit from focusing on specific aspects of the two headache types.

Adolescent↗

PubMed2001

Reduction of post-surgical adhesions with ferric hyaluronate gel: a European study.

BACKGROUND: The objective of this study was to assess the safety and efficacy of a 0.5% ferric hyaluronate gel, in reducing adhesions in patients undergoing peritoneal cavity surgery by laparotomy, with a planned 'second-look' laparoscopy. METHODS: The study was a randomized (by computer-generated schedule), third party blinded, placebo-controlled, parallel-group design conducted at five centres in Europe. Females aged 18-46 years received 300 ml ferric hyaluronate (n = 38) or lactated Ringer's (n = 39) as an intraperitoneal instillate at the completion of surgery. At second-look 6-12 weeks later, the presence of adhesions was evaluated at 24 abdominal sites. RESULTS: Patients treated with ferric hyaluronate had significantly fewer adhesions compared with controls. When adhesions formed, they were significantly less extensive and less severe in the treated group. The American Fertility Society score for adnexal adhesions was reduced by 69% in the treatment group compared with controls. The safety profile of ferric hyaluronate-treated patients was comparable with those treated with lactated Ringer's solution. CONCLUSIONS: In conclusion, ferric hyaluronate was safe and highly efficacious in reducing the number, severity and extent of adhesions throughout the abdomen following peritoneal cavity surgery.

Adnexa Uteri↗

PubMed2001

Chronic pain and difficulty in relaxing postural muscles in patients with fibromyalgia and chronic whiplash associated disorders.

OBJECTIVE: To investigate if muscle tension according to the surface electromyogram (EMG) of the shoulder flexors is increased in consecutive patients with fibromyalgia (FM) or chronic whiplash associated disorders (WAD). METHODS: A total of 59 consecutive patients with FM (n = 36) or chronic WAD (n = 23) performed 100 maximal isokinetic contractions combined with surface electromyography of the trapezius and infraspinatus. A randomized group of pain-free female (n = 27) subjects served as control group. Peak torque initially (Pti) and absolute and relative peak torque at endurance level (PTe, PTer) were registered as output variables, together with the EMG level of unnecessary muscle tension, i.e., the signal amplitude ratio (SAR). RESULTS: The patient groups had a higher level of unnecessary tension initially and at the endurance level. The patients had lower absolute output (PTi and PTe), but the relative levels (PTer) did not differ comparing all 3 groups. Subjects with FM had significantly higher body mass index (BMI) than the other groups. BMI did not influence the SAR but correlated positively with PTi. CONCLUSION: The results confirmed earlier findings that groups of patients with chronic pain have increased muscle tension and decreased output during dynamic activity compared to pain-free controls. However, the results indicated there is heterogeneity within groups of patients with the same chronic pain disorder and that not all patients with chronic pain have increased muscle tension.

Adult↗

PubMed2001

Psychosocial functioning and dental factors in adolescents with temporomandibular disorders: a case-control study.

AIMS: To examine the influence of psychosocial functioning and dental factors in adolescents with temporomandibular disorders (TMD) versus healthy subjects. METHODS: The TMD sample comprised 63 patients (21 boys and 42 girls, 33% and 67%, respectively, with a mean age of 14.9 years; range 12 to 18 years) and was compared with 64 healthy control subjects (17 boys and 47 girls, 27% and 73%, respectively, with a mean age of 14.8 years). Subjects in the TMD group had to report pain once a week or more and to have a TMD pain diagnosis according to the Research Diagnostic Criteria for TMD. Participants were clinically examined and filled out a questionnaire in which self-reported psychosocial functioning was assessed on standardized measures, including the Youth Self-Report (YSR), somatic complaints, and stress. RESULTS: No significant differences were found in dental factors among adolescents in the TMD group compared with those in the control group. Multiple pains in the body and fatigue were significantly more common in the TMD group compared with the control group. Adolescents with TMD also reported significantly higher levels of stress, somatic complaints, and aggressive behavior than their counterparts in the control group. In particular, young adolescents with TMD reported high levels of psychosocial problems. CONCLUSION: In adolescents with TMD, psychosocial factors such as increased levels of stress, somatic complaints, and emotional problems seem to play a more prominent role than dental factors.

Adolescent↗

PubMed2001

Zona pellucida binding assay--a method for evaluation of canine spermatozoa.

The present study describes the use of a zona pellucida binding assay for the evaluation of canine spermatozoa. A zona pellucida binding assay is a sperm evaluation test that is practical to perform and provides potentially useful information on the damage caused to spermatozoa by new methods of sperm storage. The addition of the detergent Equex STM paste to the cryopreservation extender has a positive effect on the zona pellucida binding capacity of cryopreserved spermatozoa. A large number of sperm-oocyte complexes need to be evaluated because of the variability in sperm binding capacity among oocytes. However, this does not constitute a major problem as canine oocytes can be stored before use in a zona pellucida binding assay and sperm-oocyte complexes can be fixed and stored until evaluation.

Animals↗

PubMed2000

Relationship between heparin binding to spermatozoa and the fertility of dairy bulls.

The presence of heparin in in vitro media has been implicated in improved fertility parameters of bull spermatozoa. In a previous study, Zhang et al. (25) obtained an estimate of bull nonreturn rates based on spermatozoal concentration, motility and zona pellucida binding (24). The objective of this study was to test for a relationship between fertility parameters previously estimated for the same batch of cryopreserved semen (25) and amount of heparin bound to spermatozoa. 3H-heparin binding to spermatozoa was assessed by radioimmunoassay, and statistical correlations were drawn to previously measured sperm characteristics. Preliminary experiments established optimal binding conditions of 25 degrees C, and 60 min incubation with 3H-heparin at a concentration of 50,000 cpm. 3H-heparin bound to an average of 2.2 x 10(6) receptors/cell with a Kd of 2.0 x 10(-7) M. The total 3H-heparin bound to spermatozoa from different bulls was significantly different (P<0.003). However, the total 3H-heparin bound to spermatozoa was not correlated with any measured sperm parameter, including zona pellucida binding, embryo cleavage and blastocyst formation, and 56-day nonreturn rates (P>0.19). Thus, the total amount of heparin bound to the surface of spermatozoa may not be relevant to fertilizing ability.

Animals↗

PubMed2000

Effect of ACTH-challenge on progesterone and cortisol levels in ovariectomised repeat breeder heifers.

In order to investigate the potential influence of stress as a component of the repeat breeding syndrome, the adrenocortical capacity for steroid production was evaluated in ovariectomised dairy heifers. In repeat breeder heifers (RBH), marginally elevated plasma progesterone levels during oestrus, so-called suprabasal progesterone levels, have earlier been measured and are believed to impair fertility. The aim was to distinguish if this progesterone could be of extra-gonadal or in this case, adrenal origin. Baseline levels of plasma cortisol and progesterone were determined as well as the corresponding response after induced acute stress in the form of an adrenocorticotropin (ACTH)-challenge. Comparisons were made between strictly selected RBH, n=5 and virgin heifers (VH), n=5 of the Swedish Red and White breed. The heifers were used as their own pre-challenge controls in a 2-day trial. On the control day, saline was injected i.v. and on the treatment day, a synthetic analogue of ACTH (60 microg Synachten(R)). Via a jugular vein catheter, blood samples were collected every 30 min for 6 h each day of the experiment. Analyses for plasma progesterone and cortisol were made. RBH had a significantly higher (P<0.01) pretreatment baseline cortisol level (10.1+/-2.3 nmol l(-1)) than VH (2.6+/-0.2 nmol l(-1)). Moreover, the cortisol response after stimuli was stronger in RBH than VH, especially concerning total hormone production (P<0. 001), but there was also a tendency towards higher peak values (P=0. 06) and longer duration of significantly increased hormone concentrations (P=0.08). Progesterone concentrations, however, did not differ between the groups. Both baseline levels (P=0.25) and posttreatment production (P=0.45) were of the same magnitude in RBH and VH. In conclusion, the study could not confirm that suprabasal progesterone concentrations during oestrus in RBH derive from the adrenal glands. Still, apparent differences were found in adrenocortical activity when ovariectomised heifers, VH and RBH, were subjected to an ACTH-challenge. It is suggested that a sustained adrenal stimulation associated with environmental or social stress could be one factor in the repeat breeding syndrome.

Adrenal Cortex↗