Dorsal hippocampus not always necessary in a radial arm maze delayed win‐shift task

Spatial working memory is important for foraging and navigating the environment. However, its neural underpinnings remain poorly understood. The hippocampus, known for its spatial coding and involvement in spatial memory, is widely understood to be necessary for spatial working memory when retention intervals increase beyond seconds into minutes. Here, we describe new evidence that the dorsal hippocampus is not always necessary for spatial working memory for retention intervals of 8 min. Rats were trained to perform a delayed spatial win shift radial arm maze task with an 8‐min delay between study and test phases. We then tested whether bilateral inactivation of the dorsal hippocampus between the study and test phases impaired behavioral performance at test. Inactivation was achieved through a bilateral infusion of lidocaine. Performance following lidocaine was compared to control trials, in which, sterile phosphate buffered saline (PBS) was infused. Test performance did not differ between the lidocaine and PBS conditions, remaining high in each. To explore the possibility that this insensitivity to inactivation was a result of overtraining, a second cohort of animals received substantially less training prior to the infusions. In this second cohort, lidocaine infusions did significantly impair task performance. These data indicate that successful performance of a spatial win‐shift task on the 8‐arm maze need not always be hippocampally dependent.     

Assessment of knowledge and attitude toward stem cells and their implications in dentistry among recent graduates of dental schools in Saudi Arabia

Background

To evaluate the knowledge and attitude level of recent dental graduates in Saudi Arabia toward stem cells and their potential therapeutic applications.

Prognostic significance of platelet count in SLE patients

Hematological abnormalities, especially thrombocytopenia (TCP), are highly prevalent among patients with systemic lupus erythematosus (SLE) and at the same time it has been reported as a significant prognostic factor of SLE course. We further investigate the correlation between platelet count and the clinical manifestations and disease activity of SLE, in a cohort of Saudi Arabian female patients. A retrospective analysis was done for the medical records of 100 SLE female patients, selected from all patients diagnosed and treated for SLE at the Rheumatology outpatient clinics in Hera’a General Hospital, Holly Makkah, Saudi Arabia. The data collected from every patient’s file included laboratory investigations (complete blood count, platelet parameters, ESR, anti-double-stranded DNA antibody, ANA), clinical manifestations, as well as SLE disease activity index (SLEDAI-2k) scores throughout a period of six sequential follow-up visits. Patients were divided into three groups according to the SLEDAI-2k: mild, moderate, and high-activity group. We found that, out of 100 patients, TCP was the most prevalent hematological abnormality evident in 15%, more than leucopenia (14%) and anemia (2%). TCP was acute in onset and associated with arthritis, neurologic manifestations, and nephritis. Platelet count showed a significant negative correlation with disease activity, in all of the three groups of patients. We concluded that platelet count has a negative correlation with disease activity in SLE patients, whatever the associated manifestations, and it should be considered as a prognostic factor, identifying patients with aggressive disease course.     

Antibiotic prophylaxis against infective endocarditis in adult and child patients: Knowledge among dentists in Saudi Arabia

Objectives:

To evaluate dentists’ knowledge regarding the prevention of infective endocarditis in Saudi Arabia and their implementation of the 2007 American Heart Association guidelines.

Methods:

In this cross-sectional study, in March 2014, 801 dentists who practice in different regions of Saudi Arabia completed a questionnaire regarding the need for antibiotic prophylaxis for specific cardiac conditions and specific dental procedures, prophylaxis regimens in adults and children, and recommendations for patients on chronic antibiotics, and in dental emergencies. The data were analyzed using one-way analyses of variance (ANOVAs) and independent t-tests, and a p-value <0.05 was considered statistically significant.

Results:

The total knowledge level regarding antibiotic prophylaxis among all participants was 52.2%, with a significant difference between dentists who graduated before and after 2007. Comparing the level of knowledge among different dental specialists, surgeons and periodontists had the highest level of knowledge regarding the use of antibiotic prophylaxis. Amoxicillin was prescribed as the drug of choice by 63.9% of the participants.

Conclusion:

This study emphasized the need for continuous education and for formal inclusion of the guidelines in the students’ curriculum, as well as for strategic placement of the guidelines in locations throughout dental clinics.Infective endocarditis (IE) is a rare, potentially life-threatening infection of the heart valves or endocardium, and it is often found in association with congenital or acquired cardiac defects. Despite advances in IE diagnosis, antimicrobial therapy, surgical techniques, and the management of complications, high morbidity and mortality rates continue to be associated with this infection.1 The basic pathology of IE involves turbulent blood flow produced by certain types of congenital or acquired heart disease that can traumatize the endothelium, resulting in the deposition of platelets and fibrin on the damaged endocardium or endothelial surface.2 This deposition can result in the formation of sterile vegetation, a condition known as nonbacterial thrombotic endocarditis.2 Invasion of the bloodstream by microbes that can colonize these damaged sites can result in IE.1 The focus of infection is determined by the ability of various microbial species to adhere to specific anatomical sites.3 Once attached to an anatomical focus, these microorganisms stimulate further deposition of fibrin and platelets on their surfaces. After they are buried, the microorganisms can multiply rapidly, apparently uninhibited by host defenses.3 Manipulation of the teeth and periodontal tissues leads to bacteremia. Different dental procedures have been associated with a broad variation in the frequency, duration, and magnitude of bacteremia.3 For this reason, many published studies have focused on prevention or on decreasing the magnitude and/or duration of bacteremia using antimicrobial agents. Amoxicillin has had a significant impact on reducing the incidence, nature, and duration of bacteremia caused by dental procedures, but it does not eliminate the bacteremia.4-6 The data from Saudi Arabia on the epidemiology of IE is lacking due to the absence of nationwide epidemiological studies. In a review of more than 10 years of data, Nashmi and Memish7 reported that rheumatic heart disease remained the most common valvular heart disease in Saudi Arabia. In a study performed in 2006 that assessed the practice of antibiotic prophylaxis for bacterial endocarditis among Riyadh dentists,8 the findings showed that 96.9% of respondents were using prophylactic antibiotics in patients susceptible to IE.The American Heart Association (AHA) has regularly reviewed and revised its guidelines for the prevention of IE since 1955, and the most recent guidelines were published in 2007.3,9-16 There has been a paucity of information in published studies regarding dentists’ knowledge of IE prevention in Saudi Arabia. Therefore, the aim of this study was to evaluate the knowledge of dentists regarding the prevention of IE in Saudi Arabia and the implementation of the 2007 AHA guidelines.     

Hemorrhagic fever in Saudi Arabia: challenge to public health,effective management and future considerations

BackgroundViral hemorrhagic fevers (VHF) refers to a group of febrile illnesses caused by different viruses that result in high mortality in animals and humans. Many risk factors like increased human-animal interactions, climate change, increased mobility of people and limited diagnostic facility have contributed to the rapid spread of VHF.MaterialsThe history of VHFs in the Saudi Arabian Peninsula has been documented since the 19^th century, in which many outbreaks have been reported from the southwestern region of Saudi Arabia. Despite presence of regional network of experts and technical organizations, which expedite support and respond during outbreaks, there are some more challenges that need to be addressed immediately. Gaps in funding, exhaustive and inclusive response plans and improved surveillance systems are some areas of concern in the region which can be dealt productively. This review primarily focusses on the hemorrhagic fevers that are caused by three most common viruses namely, the Alkhurma hemorrhagic fever virus, Rift valley fever virus, and Dengue fever virus.ConclusionIn summary, effective vector control, health education, possible use of vaccine and concerted synchronized efforts between different government organizations and private research institutions will help in planning effective outbreak-prevention and response strategies in future.     

Are the anticipated benefits of myomectomy achieved in women of reproductive age? A 5-year review of the results at a UK tertiary hospital.

Fibroids are the most common benign tumours of the pelvis in women, with a prevalence estimated at 20-50%. They are more common towards the end of the reproductive years. There is a racial preponderance, being more common in black than white women. This may relate to the aetiology, which is still poorly understood. Generally, fibroids do not cause symptoms but some sufferers do complain about pressure symptoms, abnormal vaginal bleeding and infertility. For these reasons, myomectomy is often resorted to after failure of medical interventions on the premise that it brings about improvement/cure of symptoms and enhancement of fertility. However, the evidence for these indications for surgery is hazy. An analysis of the 109 medical records of symptomatic patients who had myomectomy over a 5-year period at a tertiary centre revealed the following. Single-symptom presentation in 41 (38%), menorrhagia in 20 (18%) being the most common. Only 52 (48%) patients had medical treatment of one form or another before myomectomy. Additional operative findings included pelvic adhesions, evidence of PID and endometriosis. Thirty-four (31%) had an estimated blood loss 500 ml and 23 of these patients needed blood transfusion. There were four cases of unscheduled hysterectomies due to uncontrollable bleeding. Pyrexia was the most common (38%) postoperative complication followed by superficial wound infection in 5%. We observed improvement of symptoms, assessed over a range of 2-24 months, in 34 cases (68%) in patients without fertility symptoms who accounted for 50 of these women. The symptomatic benefit was less (36%) in the 'infertility group'. Following an observation period of over 12-36 months, 17 patients in the 'infertility group' were lost to follow-up. Two (14%) of the 14 patients who attempted in vitro fertilisation (IVF) were successful. In the non-IVF group, 13 (46%) of the 28 achieved natural conception. These results suggest that symptomatic improvement and fertility enhancement may be possible in some patients with fibroids. In view of the risks and potential failure of treatment associated with myomectomy these results, yet again, support the fact that patients should be properly counselled before embarking on myomectomy and we strongly advocate local data to form the basis of the advice given during the consultation rather than what obtains in the literature.     

Mechanisms of interaction among subinhibitory concentrations of antibiotics, human polymorphonuclear neutrophils, and gram-negative bacilli

Our hypothesis was that pretreatment of bacteria with subinhibitory concentrations (sub-MICs) of antibiotics enhances the susceptibility of the organisms to killing by human polymorphonuclear neutrophils (PMNs). Our purpose was to study a variety of drugs with different mechanisms of action and to determine whether the mechanism and locus of action altered the sub-MIC effect. The following outcome measures were used: ingestion and killing of bacteria by PMNs, bacterial killing in the absence of phagosome formation, and binding requirements of the bacteria to PMNs. The antibiotics used were representative of a variety of classes, including beta-lactams (piperacillin and imipenem) and quinolones (ciprofloxacin). Bacterial uptake and killing were measured by using standard techniques, and results were analyzed by using the analysis-of-variance technique and Dunnett's t test. Pretreatment of Escherichia coli with all drugs showed significantly enhanced killing of bacteria by PMNs, which was independent of ingestion by the phagocytes. Even in the absence of phagosome formation, statistically significant killing persisted with piperacillin-pretreated bacteria but not with imipenem- or ciprofloxacin-pretreated organisms. The opsonization experiments showed that contact between bacteria and PMNs was necessary for killing to occur. The sub-MIC effect appears to be independent of the locus or mechanism of action of the antibiotic. It results in enhanced killing by PMNs which is independent of ingestion and also may persist even in the absence of phagosome formation. Killing is dependent upon specific contact between bacteria and an intact phagocyte.     

Divergent effects of castration on prostate cancer in TRAMP mice: possible implications for therapy.

PURPOSE: Divergent responses to androgen deprivation have been found in patients and in animal models of prostate cancer. The molecular basis for these different outcomes is unknown. Our aim was to identify the molecular responses of prostate cancer with divergent outcomes to androgen deprivation in TRAMP mice. EXPERIMENTAL DESIGN: Castrated and noncastrated B6xFVB TRAMP mice were evaluated for survival, tumor development, pathology, and expressions of specific proteins at different time points. RESULTS: TRAMP mice responded differentially to androgen deprivation. In the majority, primary tumors regressed after castration (positive response), whereas in others the tumors grew even more aggressively than in the noncastrated mice (negative response). Mice with regressed tumors had the highest survival rates. Androgen receptor was elevated in all tumors from castrated mice despite significant differences in tumor sizes. In positively responding tumors, expressions of Bcl-2 and Grp78 were greatly increased by 10 weeks after castration, whereas expressions of Bax, Bcl-xl, SV40 T antigen, and c-myc were lower. These tumors also showed a reduction in proliferating cells compared with noncastrates and negatively responding tumors. Most of these changes disappeared 20 weeks after castration, by which time there was an increase in the size of primary tumors as well as in distant metastasis. CONCLUSIONS: In TRAMP prostate cancer that responded positively to castration, different expression patterns of proteins involved in cellular apoptosis, stress, and proliferation occur approximately 10 weeks after castration. This may be an optimal time for targeting Bcl-2, and perhaps Grp78, to enhance the antitumor effects of androgen deprivation.