Acute stress impairs visual path integration

Acute stress exerts substantial effects on episodic memory, which are often mediated by glucocorticoids, the end-product of the hypothalamic-pituitary-adrenal axis. Surprisingly little is known, however, about the influence of acute stress on human spatial navigation. One specific navigational strategy is path integration, which is linked to the medial entorhinal cortex, a region harboring glucocorticoid receptors and thus susceptible for stress effects. Here, we investigated effects of acute stress on path integration performance using a virtual homing task. We divided a sample of healthy young male participants into a stress group (nstress = 32) and a control group (ncontrol = 34). The stress group underwent the socially evaluated cold-pressor test, while the control group underwent a non-stressful control procedure. Stress induction was confirmed via physiological and subjective markers, including an increase of salivary cortisol concentrations. We applied linear mixed models to investigate the effect of acute stress on path integration depending on task difficulty and the presence or absence of spatial cues. These analyses revealed that stress impaired path integration especially in trials with high difficulty and led to greater decline of performance upon removal of spatial cues. Stress-induced deficits were strongly related to impaired distance estimation, and to a lesser extent to compromised rotation estimation. These behavioral findings are in accordance with the hypothesis that acute stress impairs path integration processes, potentially by affecting the entorhinal grid cell system. More generally, the current data suggests acute stress to impair cognitive functions mediated by medial temporal lobe regions outside the hippocampus.

Chronic stress is associated with specific path integration deficits

Repeated exposure to stress (chronic stress) can cause excess levels of circulating cortisol and has detrimental influences on various cognitive functions including long-term memory and navigation. However, it remains an open question whether chronic stress affects path integration, a navigational strategy that presumably relies on the functioning of grid cells in the medial entorhinal cortex. The entorhinal cortex is a brain region in the medial temporal lobe, which contains multiple cell types involved in spatial navigation (and episodic memory), and a high number of corticosteroid receptors, predisposing it as a potential target of cortisol effects. Here, our goal was to investigate the association between chronic stress and path integration performance. We assessed chronic stress via hair cortisol concentration (physiological measure) and the Perceived Stress Questionnaire (subjective measure) in 52 female participants aged 22-65 years. Path integration was measured using a virtual homing task. Linear mixed models revealed selective impairments associated with chronic stress that depended on error type and environmental features. When focusing on distance estimations in the path integration task, we observed a significant relationship to hair cortisol concentrations indicating impaired path integration particularly during trials with higher difficulty in participants with high hair cortisol concentrations. This relationship especially emerged in the absence of spatial cues (a boundary or a landmark), and particularly in participants who reported high levels of subjectively experienced chronic stress. The findings are in line with the hypothesis that chronic stress compromises path integration, possibly via an effect on the entorhinal grid cell system.

POS0146 PERIPHERAL NEUROPATHY IN PSORIASIS AND PSORIATIC ARTHRITIS: A SINGLE BLIND, CONTROLLED, ELECTROPHYSIOLOGICAL STUDY

Background:

It is well known that both psoriasis (PsO) and psoriatic arthritis (PsA) causes morbidity and disability in patients’ lives. Additional pathologies such as peripheral neuropathy (PN) may interfere with disease specific symptoms and may increase the burden of disease. Neuropathic complaints of patients with PsO and PsA are observed during patients’ follow-up (1,2). However, the presence of PN in PsO and PsA is not well defined in clinical studies and clinicians might be neglecting this issue.

Objectives:

Our aim was to investigate the presence of PN by electrophysiological methods and to examine its relationship with neuropathic pain and with treatments in patients with PsO and PsA.

Methods:

38 patients with PsA, 36 patients with PsO and 37 age&sex-matched healthy volunteers were enrolled into this prospective, single-blind study. Disease activity was assessed with Psoriasis Area Severity Index (PASI) for patients with PsO and with Disease Activity in Psoriatic Arthritis (DAPSA) score for patients with PsA. Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) score was used to evaluate neuropathic pain. All participants were electrophysiologically examined in Electromyography (EMG) Laboratory by an experienced neurologist blinded for study groups.

Results:

There were no significant differences on patients age, sex and body mass index among 3 study groups (p>0.05). However, disease duration was significantly longer in PsO group compared to PsA group (median 19.1[1-43] years in PsO vs median 7.5[2-29] years in PsA; p<0.01). PN was detected in 7 patients (19.44%) in the PsO group, 14 patients (34.21%) in the PsA group, and in 1 volunteer (2.7%) in the control group (PsO vs control: p<0.05; PsA vs control: p<0.001, PsO vs PsA: p>0.05) (Table 1). Among patients with PsA, 1 patient had ulnar neuropathy and 1 patient had both carpal tunnel syndrome (CTS) and sensory polyneuropathy. All other PNs detected electrophysiologically were CTS. Neuropathic pain was present in 11 patients (30.56%), 20 patients (52.63%) and in 2 volunteers (5.41%) in PsO, PsA and control groups consecutively (PsO vs control: p<0.05; PsA vs control: p<0.001, PsO vs PsA: p>0.05). PN did not show any significant correlation with disease activity or treatments including biological agents.

Table 1.

Results of peripheral neuropathy and neuropathic pain in control group and patients with PsO and PsA

Control Group (n=37)PsO Group (n=36)PsA Group (n=38)p^p+p&CTS1 (%2.70)7 (%19.44)13* (%34.21)0.028a<0.001a0.153aUlnar Neuropathy001 (%2.63)Polyneuropathy001* (%2.63)Total PN1 (%2.70)7 (%19.44)14 (%36.64)0.028a<0.001a0.097aLANSS Score5 (0:13)6.50 (0:16)13 (3:19)0.170b<0.001b0.004bAccording to LANSSlikely neuropathic pain2 (%5.41)11 (%30.56)20 (%52.63)0.005 a<0.001a0.054a

*: Both polyneuropathy and CTS were detected in one patient in the PsA group; Data are given as n (%) and median (minimum: maximum); a: Chi-Square Test, b: Kruskal Wallis Test; p^ value: control vs PsO, p+ value: control vs PsA, p& value: PsO vs PsA

Conclusion:

To our knowledge, this is the first study to investigate simultaneously the presence of neuropathic pain and PN by electrophysiological methods in patients with PsO and PsA. We observed PN and neuropathic pain high in patients with PsO&PsA and among them CTS appears as the most prominent neuropathy. Clinicians should keep this in mind during routine care of patients with PsO and PsA, which may improve patient-centred care. Large, prospective studies are needed to understand the characteristics of these neuropathies and its prognosis.

References:

[1]Rifbjerg-Madsen S, Christensen AW, Christensen R, Hetland ML, Bliddal H, Kristensen LE, Danneskiold-Samsøe B, Amris K (2017) Pain and pain mechanisms in patients with inflammatory arthritis: a Danish nationwide cross-sectional DANBIO registry survey. PLoS One 12(7):e0180014.

[2]Ljosaa TM, Mork C, Stubhaug A, et al. Skin pain and skin discomfort is associated with quality of life in patients with psoriasis. J Eur Acad Dermatol Venereol. 2012;26:29-35.

Disclosure of Interests:

None declared

Serum soluble lectin-like oxidized low-density lipoprotein receptor-1 levels in patients with restless legs syndrome

OBJECTIVE

The aim of this study was to assess the predisposition for atherosclerosis in patients with RLS through serum sLOX-1 (serum Lectin-Like Oxidized Low-Density Lipoprotein Receptor-1) measurements.

BACKGROUND

Recent epidemiological studies have suggested an association of RLS with certain chronic conditions such as diabetes mellitus (DM), obesity, hypertension (HT), and hyperlipidemia. LOX-1 is expressed in endothelial cells, macrophages, and in smooth muscle cells under the effect of proatherogenic conditions.

METHODS

This study was a prospective, cross-sectional, case-controlled. We measured the serum sLOX-1 levels in 37 restless legs syndrome patients and 38 controls.

RESULTS

Serum sLOX-1 level was significantly lower in the patient group. The two groups were similar in glucose, HbA1c, creatinine, LDL cholesterol, TG, HDL, total protein, albumin, AST, ALT, GGT, ALP, HGB, HCT, MCV, transferrin saturation rate (TSR), ferritin, CRP, TSH, FT4, FT3, B12, and folic acid levels. Also the two groups were similar with respect to age at menarche, number of previous births, number of abortions and/or curettage, total duration of breastfeeding, percentage of patients in menopause, and age at menopause.

CONCLUSION

Our results may suggest a lower atherosclerotic risk among RLS patients as compared to the general population (Tab. 3, Ref. 33).

Proximal muscle weakness as a result of osteomalacia associated with celiac disease: a case report

A 24-year-old woman suffering from back and hip pain with difficulty in walking was reported. She had proximal muscle weakness. Laboratory findings led to the diagnosis of osteomalacia. Positivity of antibodies strengthened suspicion of celiac disease. In patients with proximal muscle weakness, osteomalacia should be considered in differential diagnosis even in a young woman.

INTRODUCTION

A 24-year-old woman suffering from back pain, bilateral hip pain, and difficulty in walking was reported. Her symptoms had started in the first trimester of pregnancy.

METHODS

In her physical examination, proximal muscle weakness and waddling gait pattern were determined. Her lumbar spine and hip MRI revealed no obvious pathological findings. Electromyography showed a myophatic pattern.

RESULTS

Physical examination, normal values of creatine kinase, and muscle biopsy were supplied to exclude the diagnosis of primer muscle diseases. Laboratory findings led to the diagnosis of osteomalacia with normal renal function. Gastrointestinal symptoms and positivity of anti-gliadin and anti-endomysium antibodies strengthened the suspicion of celiac disease as a cause of the osteomalacia. The diagnosis of celiac disease was confirmed with duodenal mucosal biopsy.

CONCLUSION

In patients with proximal muscle weakness and waddling gait pattern, osteomalacia should be considered in differential diagnosis even in a young woman and underlying disease should be investigated.

Nosocomial meningitis in a university hospital between 1993 and 2002

The aim of this study was to establish the relationship between nosocomial meningitis (NM) and surgical interventions, type of pathogens and other hospital infections (HIs). Fifty-one patients diagnosed with NM, according to the criteria of the Centers for Disease Control and Prevention, in the Neurosurgery Department of Ibn-i Sina Hospital of Ankara University between 1993 and 2002 were evaluated retrospectively. All individuals with NM were hospitalized in the intensive care unit. Third-generation cephalosporins were used for surgical prophylaxis and broad-spectrum antibiotics were used for treatment. NM occurred in 0.34% of all admissions and accounted for 0.53% of all HIs. Fourteen cases (28%) had at least one concurrent HI, mainly originating from surgical wounds and related secondary bacteraemia. Four cases had NM following surgical site infection with the same causative agent and three cases had bacteraemia. All the individuals had surgical interventions and 26 (51%) had operations concerning ventriculoperitoneal shunt. A positive microbiological cause was found in the cerebrospinal fluid of 49 patients, with 16 cases having a polymicrobial cause. Of all 67 micro-organisms isolated, 41 (61%) were Gram-negative bacilli, 23 (34%) were Gram-positive cocci and the remaining three (5%) were Candida spp. Staphylococci were the most common pathogens (30%), followed by non-fermentative Gram-negative bacilli (22%).

Ofloxacin versus co-trimoxazole in the treatment of typhoid fever in children

Ofloxacin has been successfully used in the treatment of typhoid fever and Salmonella infectious of adults for many years. However, it has rarely been tried for the typhoid fever of children. In the present study, the therapeutic efficacy of ofloxacin in the treatment of typhoid fever in children was compared to that of co-trimoxazole. Out of 41 patients with bacteriologically documented typhoid fever, those with co-trimoxazole-resistant strains received 20 mg/kg ofloxacin twice daily for 10 days, and those with co-trimoxazole-susceptible bacteria were given 60 mg/kg co-trimoxazole twice daily for 10 days. Both groups were compared according to the clinical variables (apyrexia, resolution of gastrointestinal, central nervous system reactions and articular symptoms) and the time when cultures became negative. All patients in both groups were cured without relapse. Apyrexia, resolution of gastrointestinal, central nervous system reactions and articular symptoms were obtained in a significantly shorter time with ofloxacin than with co-trimoxazole (P < 0.05). The interval between onset of therapy and the time when cultures became negative was significantly shorter in the ofloxacin group than in the co-trimoxazole group (P = 0.005). Ofloxacin seems to be a good alternative in the treatment of typhoid fever caused by co-trimoxazole resistant salmonellae in children aged less than 16 years. It is well tolerated by the patients and it causes no side effects with short-term usage.

Tumor necrosis factor-alpha and interleukin-1 beta levels in children with bacterial, tuberculous and aseptic meningitis

Cerebrospinal fluid levels of tumor necrosis factor-alpha and interleukin-1 beta in 78 children with nonbacterial, bacterial and tuberculous meningitis, and in 34 control subjects were analyzed in order to evaluate the involvement of these cytokines in the pathogenesis of acute bacterial meningitis and their discriminative value between different etiologies of meningitis. Tumor necrosis factor-alpha and interleukin-1 beta levels were significantly higher in bacterial and tuberculous meningitis than in aseptic meningitis and in control subjects (p < 0.0001). There was no difference in the levels of tumor necrosis factor-alpha and interleukin-1 beta between nonbacterial meningitis and control groups. The finding that both tumor necrosis factor-alpha and interleukin-1 beta are increased in the cerebrospinal fluid of patients with bacterial and tuberculous meningitis whereas normal levels of these two cytokines have been found in patients with nonbacterial meningitis signifies that these cytokines may be used to differentiate between bacterial and nonbacterial meningitis.

Antibiotic susceptibilities of Salmonella serogroups isolated from Turkish children

This study is performed to show the serogroup distribution and in-vitro antibiotic susceptibilities of Salmonella species that cause either gastroenteritis with/without bacteremia or enteric fever at Hacettepe University Ihsan Doğramaci Children's Hospital. Of the 309 Salmonella strains evaluated, serogroup B was the most common isolate (56%) followed by serogroup D (33%). Antibiotic susceptibility tests using the disk diffusion technique revealed resistance rates of 43 percent for ampicillin, 41 percent for chloramphenicol, 29 percent for trimethoprim-sulfamethoxazole (SXT) and 32 percent for ceftriaxone among Salmonella serogroup B. The same rates were 10, eight, seven and zero percent for Salmonella serogroup D, and seven, 14, and zero percent for serogroup C, respectively. S.thypi strains susceptible to all antibiotics studied except tetracycline (33% resistant). No resistance was detected against the quinolones. The antibiotic resistance of Salmonella species isolated from children seems to be important, especially in serogroup B. Susceptibility tests should be considered in the antimicrobial therapy of Salmonella infections where indicated.

Antibiotic susceptibilities of enterococci isolated from Turkish children

To evaluate the antibiotic resistance rates of enterococci isolated at Hacettepe Children's Hospital, in vitro antibiotic susceptibility tests were performed in 77 enterococci (32 hospital, 45 nonhospital strains) isolated from various clinical specimens in 1994. Microbroth dilution tests against ampicillin, vancomycin, gentamicin and streptomycin were performed according to the NCCLS standards. High-level resistance to aminoglycosides was investigated. Ampicillin resistance rates were 21.9 percent and 2.2 percent for hospital and nonhospital strains, respectively (p < 0.01). The same rates were 46.9 and 13.3 percent for gentamicin (p < 0.01), and 15.6 and 13.3 percent for streptomycin (p = 0.25). No resistance was detected against vancomycin. Six strains (7.8%) showed high-level resistance to both aminoglycosides studied. Special attention should be paid to enterococci isolated from hospitalized patients. Appropriate antibiotic use in serious infections can only be achieved by choosing an appropriate regimen according to antibiotic susceptibility tests. Periodic evaluation of the antibiotic susceptibility patterns of enterococci is necessary for the empirical treatment of infections due to these microorganisms.

Microorganisms involved in acute bacterial meningitis in children and the role of Haemophilus influenzae

Acute bacterial meningitis (ABM) is an important cause of mortality and neurological damage in children. Documentation of the etiological agents is very important both for the treatment of patients and for prophylactic approaches. H.influenzae, N.meningitidis and S.pneumoniae are the three major pathogens involved in ABM. In Turkey for many years H.influenzae has not been isolated in cerebrospinal fluid (CSF) specimens. In order to show the bacteria involved in ABM in our hospital and to see the role of H.influenzae, we investigated the CSF of 59 patients with bacterial meningitis using Gram and Wayson stains, culture and latex agglutination techniques. The agents were determined in 38 (64.4%) specimens by using culture positivity in 30 (50.8%), and latex or stain positivity in eight (13.6%) specimens. The microorganisms causing ABM included S.pneumoniae (25.6%), gram-negative enteric bacillI (17.9%), N.meningitis (12.8%), alpha hemolytic streptococci (10.3%), H.influenzae (10.3%), nonfermentative gram-negative bacillI (5.1%), candida spp. (5.1%), group B streptococci (2.6%), coagulase negative staphylococci (2.6%), S.aureus (2.6%) and pseudomonas spp. (5.1%). In this study it has been shown that H.influenzae can cause ABM in Turkish children. Multicentric studies from different parts of Turkey will be helpful in showing the real incidence in our country.

Changing patterns of the prevalence of different Shigella species and their antibiotic susceptibilities in Ankara, Turkey

Shigella flexneri was the most common Shigella serogroup isolated in Turkey. Recently, an increase in the number of Shigella sonnei isolates was noticed. A retrospective analysis of 2,710 isolates, obtained from stools of Turkish children between January 1980 and September 1994, revealed that, between 1980 and 1987, S. flexneri was the most common subgroup. The isolation rate of S. sonneri increased steadily from 1987 to 1994 reaching to a peak of 78% of all isolates in 1991. The antibiotic susceptibility of 206 strains isolated in 1994 was also studied. A marked difference between the two species was observed for chloramphenicol (98% susceptibility in S. sonnei versus 20% in S. flexneri, ampicillin (90% vs. 18%), ampicillin-sulbactam (98% vs. 53%), and tetracycline (46% vs. 18%) (p < 0.001). Susceptibility to trimethoprim-sulphamethoxazole was similar between the two groups (42% vs. 38%). All isolates were susceptible to ciprofloxacin and ceftriaxone. Comparing our results with resistance rates in 1989, a marked increase in amplicillin (from 44.1% to 82%), chloramphenicol (from 36.7% to 56%) and trimethoprim-sulphamethoxazole (from 35.8% to 62%) resistance was observed.

[Penicillin resistance in Streptococcus pneumoniae strains]

In this study a total of 87 Streptococcus pneumoniae strains were tested for their susceptibility to penicillin with disk diffusion method by using 5 micrograms methicillin disks. In 68 strains susceptibility to penicillin was also determined by using agar dilution method performed in Mueller-Hinton agar supplemented with 5% sheep blood. Of 63 adult isolates tested with disk-diffusion method 35 strains (55.6%) were susceptible to penicillin, 24 strains (38.1%) had low level resistance and 4 strains (6.3%) had high-level resistance to penicillin. Of 24 S. pneumoniae isolates recovered from children 5 (20.8%) were penicillin susceptible, while 11 (45.8%) had low level resistance and 8 (33.4%) had high level resistance to penicillin. These values were 40 (45.9%), 35 (40.3%) and 12 (13.8%) in total isolates respectively. Of 44 isolates in which MIC values of penicillin were determined by agar dilution method, 34 strains (77.3%) were penicillin susceptible and 10 strains (22.7%) had low level resistance while none of these strains had high level resistance to penicillin. Of 24 children isolates tested with agar dilution method 11 strains (45.8%) were susceptible to penicillin, 8 strains (33.4%) showed low level resistance and 5 strains (20.8%) showed high level resistance to penicillin. For total of 68 isolates these values were 45 (66.1%), 18 (26.4%) and 5 (7.3%) respectively. These findings indicate the need to perform antibiotic susceptibility testing of all pneumococcal isolates to avoid therapeutic failure.

[Comparison of two different media-atmosphere combinations on the isolation of group A beta-hemolytic streptococci from throat cultures]

In this study effects of incubation of sheep blood agar medium in aerobic conditions and incubation of sulfamethoxazole-trimethoprim containing sheep blood agar medium in 5 to 10% CO2, of the isolation of group A beta hemolytic streptococci from throat cultures were compared. 608 throat swab specimens were studied. Each agar medium was evaluated after 24 and 48 hours of incubation period. The aerobic incubation of sheep blood agar plates for 24 hours yielded 108 (17.7%) strains of beta hemolytic streptococci, of these 96 (15.8%) strains being group A. 113 (18.5%) strains of beta hemolytic streptococci were isolated after 48 hours of incubation and 100 (16.4%) of these were group A. The number of beta hemolytic streptococci isolated in 5 to 10% CO2 atmosphere for 24 hours was 62 (10.2%), and 57 (9.3%) of these were group A. When the incubation period was prolonged to 48 hours, the total number of beta hemolytic streptococci isolated increased to 82 (13.5%) and 76 (12.5%) of these were determined as group A. The difference between these two combinations was significant for 24 hours of incubation, but not significant for 48 hours of incubation. The highest isolation rate for group A streptococci was achieved in aerobic incubation of sheep blood agar plates for 48 hours.

[Group B streptococcal endocarditis]

In this article, a case of group B streptococcal endocarditis in a diabetic patient, taking immunosuppressive therapy because of dermatomyositis is reported.