A Molecular Integrative Study on the Inhibitory Effects of WRR and ERW on Amyloid ß Peptide (1-42) Polymerization and Cell Toxicity.

Alzheimer's disease (AD) is a neurodegenerative disease and the main pathological characteristic of AD is the deposition of Aß42 in the brain. Inhibition of Aß42 polymerization is one of the important research directions. Due to the pathological complexity of Alzheimer's disease, studies on Aß42 polymerization inhibitors have not made significant progress worldwide. Using an independently constructed structure database of oligopeptides, in this study, molecular docking, umbrella sampling analysis of free energy, ThT fluorescence detection of Aß42 polymerization, transmission electron microscopy, and flow cytometry detection of reactive oxygen species (ROS) and apoptosis were performed to screen tripeptides and pentapeptides that inhibit polymerization. It was found that two tripeptides, i.e., WRR and ERW, bind stably to the core of Aß42 polymerization in the molecular dynamics analysis, and they significantly inhibited the aggregation of Aß42 and reduced their cell toxicity in vitro.

Sex-biased, but not plumage color-based, prevalence of haemosporidian parasites in free-range chickens.

Previous studies found a relationship between blood parasite infection and bird gender, with higher prevalence in males. Some studies also found a relationship between host plumage color and parasitic infection, while others did not. Here, we investigated the blood parasite prevalence in correlation with sex and plumage color in free-range chickens (Gallus gallus domesticus) in China. We analyzed a total of 297 blood samples, out of which 234 chickens tested positive for haemosporidian parasites, with 78.5% parasite prevalence. Out of 139 males, 118 tested positive with 84.8% parasite prevalence while 116 of 158 female samples tested positive (73.4%). Leucocytotozoon was the most frequent genus isolated (193 infected individuals /234 birds), followed by Plasmodium (41 infected individuals/234 birds), with no Haemoproteus parasites being detected. There were no significant differences in the body parameters and chicken color plumages with regards to the infection status. Our study indicated that blood parasite infection was significantly different between male and female chickens, with infection prevalent in males.

Effect of Breeding Season on Haemosporidian Infections in Domestic Chickens.

Reproduction is believed to contribute to the frequently observed seasonal cycles in parasite loads in many organisms, as an investment in reproduction by the host could result in a higher susceptibility to parasites. In this study, we examined the impact of breeding season on haemosporidian infection in free-range chickens (Gallus gallus domesticus). We sampled a total of 122 chickens (66 chickens during the breeding season of April 2017 and 56 chickens during the non-breeding season of January 2017) to test for haemosporidian infections. The result showed that 56 out of 66 chickens examined during the breeding season tested positive for parasites (84.8% parasite prevalence), whereas 39 out of 56 chickens tested positive for parasites during the non-breeding season (69.6% parasite prevalence). Moreover, among the 11 Leucocytozoon lineages and 2 Plasmodium lineages identified, the parasite lineages that infected chickens during the breeding season were more diversified than those that affected chickens during the non-breeding season. This study indicated that chickens have a higher incidence of haemosporidian infection and a greater diversity of haemosporidian parasite lineages during the breeding season relative to the non-breeding season.

Risk factors of tubal infertility in a tertiary hospital in a low-resource setting: a case-control study.

BACKGROUND: Infertility is the inability to sustain a pregnancy in a woman with regular (2-3 times per week) unprotected sexual intercourse for a period of 1 year. This is a major public health problem that remains under-recognised in Cameroon and most countries in sub-Saharan Africa. This study aimed at identifying the risk factors associated with tubal infertility in a tertiary hospital in Douala, Cameroon. METHODS: We conducted a case-control study at the Obstetrics, Gynaecology and Radiology Departments of the Douala Referral Hospital from October 1, 2016, to July 30, 2017. We recruited 77 women with tubal infertility diagnosed using hysterosalpingography and 154 unmatched pregnant women served as controls. Data on socio-demographic, reproductive and sexual health, and radiologic assessments were collected using a pretested questionnaire. The data were analysed using the Statistical Package for the Social Sciences (SPSS) software version 24.0. Logistic regression models were fitted to identify demographic, reproductive health factors, surgical, medical and toxicological factors associated with tubal infertility. The adjusted odds ratios (AOR) and their 95% confidence interval were interpreted. Statistical significance set at p < 0.05. RESULTS: Sixty-one per cent of respondents had secondary infertility. Following multivariate logistic regression analysis, respondents who were housewives (AOR 10.7; 95% CI: 1.68-8.41, p = 0.012), self-employed (AOR 17.1; 95% CI: 2.52-115.8, p = 0.004), with a history of Chlamydia trachomatis infection (AOR 17.1; 95% CI: 3.4-85.5, p = 0.001), with Mycoplasma infection (AOR 5.1; 95% CI: 1.19-22.02, p = 0.03), with ovarian cyst (AOR 20.5; 95% CI: 2.5-168.7, p = 0.005), with uterine fibroid (AOR 62.4; 95% CI: 4.8-803.2, p = 0.002), have undergone pelvic surgery (AOR 2.3; 95% CI: 1.0-5.5, p = 0.05), have undergone other surgeries (AOR 49.8; 95% CI: 6.2-400, p = 0.000), diabetic patients (AOR 10.5; 95% CI 1.0-113.4, p = 0.05) and those with chronic pelvic pain (AOR 7.3; 95% CI: 3.2-17.1, p = 0.000) were significantly associated with tubal infertility while the young aged from 15 to 25 (AOR 0.07; 95% CI: 0.01-0.67, 0.021), those in monogamous marriages (AOR 0.05; 95% CI: 0.003-1.02, p = 0.05), as well as those with a history of barrier contraceptive methods (condom) (AOR 0.17; 95% CI: 0.03-1.1, p = 0.06) were less likely to have tubal infertility. CONCLUSION: The following factors were independently associated with tubal infertility: being a housewife, self-employed, history of Chlamydia trachomatis, Mycoplasma infection, and uterine fibroid. Furthermore, a history of pelvic surgery and other surgeries, diabetes mellitus, and chronic pelvic pain were also associated with tubal infertility. Young age, persons in monogamous marriages and users of barrier methods of contraception (condom) were less likely to have tubal infertility. Identification of these factors will be a target of intervention to avoid tubal infertility.

Vaginal leiomyoma: medical imaging and diagnosis in a resource low tertiary hospital: case report.

BACKGROUND: In the literature under review there are about 300 reported cases of vaginal leiomyomas with none from Cameroon. We report a case of vaginal leiomyoma and highlight the diagnostic challenges faced at the Douala Referral Hospital (DRH), Cameroon. CASE PRESENTATION: A 36-year-old G3P3002 sexually active Cameroonian married woman reported dysuria, dyspareunia, cessation of sexual intercourse and offensive smelling vaginal discharge for 6 months and a 3-year history of a vaginal tumour; she was misdiagnosed despite ultrasonography and magnetic resonance imaging (MRI) but was corrected by an experienced radiologist. She underwent first look laparoscopy, surgical excision of the tumour through the vagina and histopathology analysis that confirmed leiomyoma. CONCLUSION: Posterior location of vaginal leiomyomas found in this case is a rare occurrence. The diagnosis is based on careful examination and preoperative imaging (ultrasonography and MRI). However, the definitive diagnosis is usually made intra-operatively. We combined laparoscopic exploration of the internal genital organs and per vaginal excision of the vaginal leiomyoma. Thus, we recommend frozen section biopsy to exclude leiomyosarcoma.

Virginity-sparing management of hematocolpos with imperforate hymen: case report and literature review.

Imperforate hymen results from failure of the endoderm of the urogenital sinus to completely canalize and has an incidence of 0.01% to 0.05%. This sometimes presents as a pelvic mass that compresses the bladder causing acute urinary retention. A 13-year-old girl was referred to our department with a history of primary amenorrhea, cyclic lower abdominal pain, abdominal-pelvic mass, constipation and acute urinary retention. She had an ultrasonography misdiagnosis of a huge ovarian mass before referral to our unit. On examination, the vagina was bulging and compressing the rectum. Repeat abdominal ultrasonography confirmed the diagnosis of hematometrocolpos. She underwent X-shaped hymenotomy with a favorable outcome. Diagnosis of imperforate hymen requires high suspicion index. Virginity-sparing surgery constitutes a good treatment option for cultural and religious reasons.

Ultrasonographic prevalence and characteristics of non-palpable thyroid incidentalomas in a hospital-based population in a sub-Saharan country.

BACKGROUND: Thyroid incidentalomas (TI) are highly prevalent asymptomatic thyroid nodules with ultrasound as the best imaging modality for their detection and characterization. Although they are mostly benign, potential for malignancy is up to 10-15%. In sub-Saharan Africa little data exists on the prevalence and risk categorization of TI. The aim of this study was to determine the prevalence and ultrasound characteristics of non-palpable thyroid incidentalomas among adults in sub-Saharan setting. METHODS: A cross sectional study was carried out between March and August 2015, at two university teaching hospitals. Sampling was consecutive and included all adults aged ≥ 16 years, presenting for any ultrasound other than for the thyroid, with no history or clinical signs of thyroid disease, and no palpable thyroid lesion. Ultrasound was done using 4 to 11 MHz linear probes. Subjects with diffuse thyroid abnormalities were excluded. Variables studied were age, gender, thyroid volume, ultrasound characteristics of thyroid nodules, TIRADS scores. Differences were considered statistically significant for p-value < 0.05. RESULTS: The prevalence of TI was 28.3% (126 persons with TI /446 examined). This prevalence was 46.2% in population ≥ 61-year-old; 6.3% in population ≤ 20-year-old; 33.3% for females and 18.4% for males (p < 0.001). Of the 241 TI found, 49.4% were cysts, 33.6% solid, 17.0% mixed; 37.8% <5 mm and 22% >10 mm. Solid TI were mainly hyperechoic (42.0%), 3/81 were markedly hypoechoic. Sixty-nine out of 126 persons with TI (54.8%) had at least two nodules. Solitary nodules were predominant in the age group ≤20 years. Of 241 TI, 129 (53.5%) were classified TIRADS 2, 81 (33.6%) TIRADS 3, 25 (10.4%) TIRADS 4A, 6 (2.5%) TIRADS 4B, and none TIRADS 5. Characteristics associated with increased risk of malignancy where mostly founded on solid nodules (p < 0.000) and nodules larger than 15 mm (p < 0.001). CONCLUSION: Thyroid incidentalomas were very frequent with a prevalence of 28.3% and potential risk of malignancy in 12.9%. Prevalence had a tendency to increase with age and in female. Cystic nodules were the most prevalent. Potential for malignancy would be increased for larger and solid nodules.

Isothermal Nucleation Rates of n-Propanol, n-Butanol, and n-Pentanol in Supersonic Nozzles: Critical Cluster Sizes and the Role of Coagulation.

We follow the nucleation of n-alcohols, n-propanol through n-pentanol, in two sets of supersonic nozzles having differing linear expansion rates. Combining the data from static pressure trace measurements with small-angle X-ray scattering we report the experimental nucleation rates and critical cluster sizes. For n-propanol, position resolved measurements clearly confirm that coagulation of the 2-10 nm size (radius) droplets occurs on the time scale of the experiment but that the effect of coagulation on the results is minimal. Under the conditions of the current experiments, our results suggest that alcohols have critical clusters that range from the dimer (n-pentanol) to the hexamer (n-propanol). We then compare the experimental results with classical nucleation theory (CNT), the Girshick-Chiu variant of CNT (GC), and the mean field kinetic nucleation theory (MKNT). Both CNT and MKNT underestimate the nucleation rates by up to 5 and 7 orders of magnitude, respectively, while GC theory predicts rates within 2 orders of magnitude. Correspondingly, the critical cluster size for all alcohols is overpredicted by factors of 2-9 with agreement improving with increasing chain length. An interesting byproduct of our experiments is that we find that the coagulation rate is enhanced by a factor of 3 over the value one would calculate for the free molecule regime.

Lowering the prophylactic platelet transfusion threshold: a prospective analysis.

The 20 x 10(9) /L threshold for prophylactic platelet transfusion may be unnecessarily high. Few prospective studies, however, in which other trigger values were tested have been published. In this study all hospitalized, thrombocytopenic adult hematology-oncology patients in our institution were prospectively evaluated daily for hemorrhage and platelet transfusion during a one year period; no patients were excluded for bleeding or infectious problems. By design, during the initial six-months (baseline period), the prophylactic platelet transfusion trigger was 20 x 10(9) /L; for the second six-months (study period) this threshold was changed to 10 x 10(9) /L. Patients studied during the two periods did not differ significantly in age, gender, diagnosis, blood or marrow transplant status, and duration of neutropenia. Compliance with the thresholds was 95.6% (baseline period) and 93.5% (study period). For patients with platelet counts under 20 x 10(9) /L, the mean use of platelet transfusions per patient per day was significantly lower in the study period (4.47) than in the baseline period (6.48; p<0.001). Both mean prophylactic (1.54/patient-day) and therapeutic (2.93/patient-day) platelet transfusions were reduced in the study period compared with the baseline period (2.26 and 4.22/patient-day, respectively). Hemorrhage was slightly reduced in the study period compared with the baseline period: major hemorrhage, 15.2% vs. 18.4% (p=0.014); minor hemorrhage, 63.6% vs. 70.1% (p<0.001). Thus, hemorrhage was not increased with the lower trigger level. A 10 x 10(9) /L prophylactic platelet transfusion threshold value is safe and effective.

Determination of melanotan II in rabbit urine using solid-phase extraction sample preparation followed by reversed-phase high-performance liquid chromatography.

A solid-phase extraction (SPE) method has been developed for the isolation of melanotan II from rabbit urine. The proposed extraction method makes it possible to selectively isolate melanotan II without significant loss of the peptide. Standard curves obtained from high-performance liquid chromatographic (HPLC) analysis of spiked urine extracts are linear from 0.1 to 4.0 micrograms/ml. The analytical method is shown to be highly reproducible, giving a relative standard deviation of less than 5% for both between-day and same-day analyses. The accuracy of the method obtained from standard plots ranges from -3.3 to 3.1%.

Reliability of automated platelet counts: comparison with manual method and utility for prediction of clinical bleeding.

The 20 x 10(9)/L (20,000/microliters) threshold for prophylactic platelet transfusion may be unnecessarily high. The widespread use of this threshold may reflect lack of confidence in the reliability of low platelet counts. We evaluated the performance of automated platelet counts and their relation to clinical bleeding. First, we prepared serial blood dilutions with "target" platelet counts from 2 to 40 x 10(9)/L. For the 48 measurements on 2 x 10(9)/L "target" dilutions, values of 1 or 2 x 10(9)/L were obtained with the Sysmex NE-8000 analyzer (mean 1.44 x 10(9)/L; SD 0.31 x 10(9)/L). Similarly, for 5 x 10(9)/L "target" counts, automated counts were 3-6 x 10(9)/L (mean 4.42 x 10(9)/L; SD 0.18 x 10(9)/L). Similar results were observed with all other "target" levels, with coefficients of variation (CV) from 6.39% to 7.71% with 10-40 x 10(9)/L "target" values. Secondly, we compared triplicate automated and manual platelet counts on thrombocytopenic patients with platelet counts from 4-30 x 10(9)/L. The triplicate automated platelet counts differed by no more than 5 x 10(9)/L among themselves, whereas the manual counts varied by as much as 30 x 10(9)/L. Mean platelet counts: automated, 14.40 x 10(9)/L (CV 10.12%); manual, 16.48 x 10(9)/L (CV 30.39%) (P = 0.038 for counts; P < 0.001 for CV). Finally, we prospectively evaluated bleeding in thrombocytopenic patients (1,809 patient-days of observation). Univariate and multivariate logistic regression analysis revealed highly significant correlations between the automated platelet count and major and minor bleeding manifestations. Thus, automated platelet counts are highly reliable and accurately predict clinical bleeding. The use of automated analyzers should facilitate improved prophylactic platelet transfusion protocols.