ON THE PRESERVATION OF TYPHUS FEVER RICKETTSIAE IN CULTURES

1. Cultures of typhus fever rickettsiae were as a rule found to remain viable and virulent after being stored at 37° and –20°C. for several months, whereas they failed to survive when stored at the intermediate temperatures of 20° and –4°C. for 4 weeks and 10 days respectively. In one instance cultures were stored at 37°C. for 8 months without having been transferred, and were subsequently found to be viable and infectious. 2. The conditions influencing such long survival of an organism which seems to require living tissue for multiplication (as filterable viruses do in general) are discussed. 3. Typhus-infected tissues (minced guinea pig tunica) suspended in a serum-Tyrode mixture in sealed flasks remained infectious at 37°C. for at least 10 weeks. 4. Additional evidence for the etiological significance of the rickettsiae in typhus fever is obtained from the experiments described.     

STUDIES ON THE CULTIVATION OF THE TYPHUS FEVER RICKETTSIA IN THE PRESENCE OF LIVE TISSUE

1. Rickettsia prowazeki can be cultivated for many generations in vitro, without diminution in numbers or virulence, in media similar to those described by Maitland, Rivers, and others for the cultivation of certain viruses. In all probability, such cultures can be maintained indefinitely. 2. It has been impossible, thus far, to cultivate the typhus rickettsia without employing living tissue.     

Einzelreferate und Buchbesprechungen

Ohne Zusammenfassung     

The Matrix Matters: Beverage Carbonation Impacts the Timing of Caffeine Effects on Sustained Attention

Both caffeine and the perception of refreshment delivered by cooling, tingling, and mouth-watering flavors have individually been shown to positively impact cognitive performance and mood, though presently there is limited evidence on their possible combined effects. This study explored the contribution of refreshing compounds in beverages, namely, carbon dioxide and citric acid, on the acute effects of caffeine on sustained attention and self-rated physical and mental energy. A randomized, controlled crossover trial was conducted by testing three products: a carbonated caffeinated beverage; a comparator caffeinated beverage; and a flavor-matched control beverage. Findings from 24 healthy adults revealed product-dependent variations in cognitive performance during a 60-min visual sustained-attention task, suggesting that the carbonated-caffeinated beverage led to faster, greater and more consistent levels of accuracy, compared to the control beverage. Specifically, significant differences were found between: (1) the carbonated-caffeinated beverage and the caffeinated beverage, and (2) between the caffeinated beverage and the control beverage for number of hits, reaction time and false alarm scores. Both caffeinated beverages led to higher physical and mental energy, and lower physical and mental fatigue 60-min post-consumption. These findings suggest beneficial effects on sustained attention through the combination of caffeine with refreshing compounds.     

Validation of the Italian Version of the SARC-F Questionnaire to Assess Sarcopenia in Older Adults

Background: SARC-F is a simple sarcopenia screening tool. This study aimed to examine the validity of the Italian version of SARC-F. Methods: A total of 97 elderly individuals (37/60 males/females, 65 years and older) who met the study’s selection criteria were included. SARC-F was translated into the Italian language in a culturally responsive manner. The total score was calculated by adding the scores on the five items. The participants were divided into two groups according to the total score (SARC-F < 4 vs. SARC-F ≥ 4), and their associations with various factors (handgrip test, chair stand test, and Skeletal Muscle Index assessed by DXA) have been examined by gender. In addition, the tool’s validity was analyzed by comparing it with different international working group diagnostic criteria for sarcopenia. Results: The total prevalence of sarcopenia according to the SARC-F was 14.2% and, specifically, 12.8% among men and 14.3% in women. The sensitivity of the SARC-F was (male (M): 11–50% and female (F): 22–36%) medium-low compared with the European, international, and Asian criteria of sarcopenia; however, SARC-F showed a high specificity (M: 77.3–100% and F: 79.5–100%) and a moderate Cronbach’s alpha coefficient of (0.669 (CI95%: 0.358–0.830). The participants in the SARC-F ≥ 4 group had poorer handgrip for EWGSOP2 (p < 0.001) and chair stand (p < 0.001) than the participants in the SARC-F < 4 group. Conclusions: The Italian language version of SARC-F showed high specificity, moderate reliability, and good associations with other predictive tests. The Italian version of SARC-F appears to be a useful screening tool for the diagnosis of sarcopenia in Italian elderly populations.     

Efficacy of a spatial repellent for control of Aedes-borne virus transmission: A cluster-randomized trial in Iquitos,Peru

Over half the world’s population is at risk for viruses transmitted by Aedes mosquitoes, such as dengue and Zika. The primary vector, Aedes aegypti, thrives in urban environments. Despite decades of effort, cases and geographic range of Aedes-borne viruses (ABVs) continue to expand. Rigorously proven vector control interventions that measure protective efficacy against ABV diseases are limited to Wolbachia in a single trial in Indonesia and do not include any chemical intervention. Spatial repellents, a new option for efficient deployment, are designed to decrease human exposure to ABVs by releasing active ingredients into the air that disrupt mosquito–human contact. A parallel, cluster-randomized controlled trial was conducted in Iquitos, Peru, to quantify the impact of a transfluthrin-based spatial repellent on human ABV infection. From 2,907 households across 26 clusters (13 per arm), 1,578 participants were assessed for seroconversion (primary endpoint) by survival analysis. Incidence of acute disease was calculated among 16,683 participants (secondary endpoint). Adult mosquito collections were conducted to compare Ae. aegypti abundance, blood-fed rate, and parity status through mixed-effect difference-in-difference analyses. The spatial repellent significantly reduced ABV infection by 34.1% (one-sided 95% CI lower limit, 6.9%; one-sided P value = 0.0236, z = 1.98). Aedes aegypti abundance and blood-fed rates were significantly reduced by 28.6 (95% CI 24.1%, ∞); z = −9.11) and 12.4% (95% CI 4.2%, ∞); z = −2.43), respectively. Our trial provides conclusive statistical evidence from an appropriately powered, preplanned cluster-randomized controlled clinical trial of the impact of a chemical intervention, in this case a spatial repellent, to reduce the risk of ABV transmission compared to a placebo.

Aedes-borne viral diseases (ABVDs) [e.g., dengue (DENV), chikungunya, Zika (ZIKV), and yellow fever] are devastating, expanding global public health threats that disproportionally affect low- and middle-income countries. DENV, one of the most rapidly increasing vector-borne infectious diseases, results in ∼400 million infections each year (1, 2), with 4 billion people at risk for infection annually (3). Currently, the primary means for ABVD prevention is controlling the primary mosquito vector, Aedes aegypti. Existing vector control interventions, however, have failed to prevent ABV transmission and epidemics (4–6).There is an urgent need to develop evidence-based guidance for the use of new and existing ABV vector control tools. The evidence base for vector control against ABVs is weak, despite considerable government investments in World Health Organization (WHO)-recommended control of larval habitats (larviciding, container removal) and ultra-low-volume insecticide spraying (4, 5, 7–9). These strategies continue to be implemented despite the lack of rigorously generated data from controlled clinical trials demonstrating they reduce ABV infection or disease (6). The only ABV intervention with a proven epidemiological impact in a cluster-randomized control trial (cRCT) assessed community mobilization to reduce mosquito larval habitats (10). A recent test-negative trial with Wolbachia-infected mosquitoes reported a significant reduction of DENV illness in Indonesia (11).Spatial repellents (SRs) are devices that contain volatile active ingredients that disperse in air. The active ingredients can repel mosquitoes from entering a treated space, inhibit attraction to human host cues, or disrupt mosquito biting and blood-feeding behavior and, thus, interfere with mosquito–human contact (12–14). Any of these outcomes reduce the probability of pathogen transmission. Pyrethroid-based SRs have shown efficacy in reducing malaria infections in China (15) and Indonesia (16). There have, however, been no clinical trials evaluating the protective efficacy (PE) of SRs against ABV infection or disease.To generate evidence for public health consideration, we conducted a double-blinded, parallel cRCT to demonstrate and quantify the PE of a transfluthrin-based SR to reduce ABV infection incidence over 2 y in a human cohort in Iquitos, Peru.     

Secondary biogenic amine deficiencies: genetic etiology,therapeutic interventions,and clinical effects

neurogenetics - Monoamine neurotransmitter disorders present predominantly with neurologic features, including dystonic or dyskinetic cerebral palsy and movement disorders. Genetic conditions that...     

The clinical relevance of ultra-widefield angiography findings in patients with central retinal vein occlusion and macular oedema receiving anti-VEGF therapy

AimsTo report, using ultra-widefield angiography (UWFA) the area, distribution, and change in retinal capillary nonperfusion (RCNP) at baseline and 100 weeks in eyes with central retinal vein occlusion (CRVO) receiving anti-VEGF for macula oedema.MethodsProspective longitudinal multi-centre cohort study. Adults with CRVO treated with anti-VEGF therapy for macular oedema underwent UWFA at baseline and week-100. The area, distribution, and change in total, peripheral and posterior pole RCNP were determined.ResultsOf 153 eyes at baseline, mean area of RCNP was 34.3DA and 12 (7.8%) had ≥75DA RCNP. More than 10DA RCNP was present in the temporal periphery in 75.8% of eyes vs. 10.5% in the nasal periphery. At week-100, mean RCNP was 42.1DA with a median change from baseline of 3.3DA 95% CI [0.4, 7.3]; p < 0.01. Of 146 eyes with ≤10DA of posterior pole RCNP at baseline, 16/146 (11.0%) progressed to >10DA at week-100. These eyes had a median increase in total RCNP of 69.7DA [95% CI 27.2–85.4] vs 0DA [0.0–1.4]; p < 0.001 for those who did not, and two developed neovascular glaucoma. Larger baseline area of RCNP and history of glaucoma were risk factors for posterior pole RCNP developing.ConclusionsWith UWFA, significant baseline RCNP was identified in the majority of CRVO patients, notably in the temporal periphery, but large increases over 100 weeks were uncommon. Development of >10DA posterior pole RCNP is a marker for widespread RCNP and in such cases the risk of anterior segment neovascularisation is not abolished by concomitant anti-VEGF therapy.Subject terms: Retinal diseases, Vision disorders     

Assessing parasitic infestation of vegetables in selected markets in Metro Manila,Philippines

ObjectiveTo assess the parasitic infestation of vegetables in selected markets in Metro Manila, Philippines.MethodsA total of 80 vegetables were purchased from public and private markets in Munoz, Quezon City, and Alabang, Muntinlupa City. Vegetables were washed, and the washings were collected and examined for parasitic organisms.ResultsIn all vegetables examined, 36 of 80 (45.0%) were infested with parasitic organisms. Vegetables obtained from Muntinlupa City showed that 17 of 40 (42.5%) have parasitic infestation as compared with those obtained from Quezon City with 19 of 40 (47.5%). Significant differences on the parasitic organisms existed between the public and private markets and between the two locations (P<0.05).ConclusionsFindings indicate that vegetables can be potential source of parasitic infection. There is a need to be vigilant in ensuring that foodstuffs sold in our market systems are safe and fit for consumption.