Determining magnification for reading with low vision

Background : In the past, practitioners have used distance and/or near visual acuity (VA) to calculate required magnification for low vision aids. Magnification was usually under‐estimated when compared with the final magnification prescribed. Recent studies have emphasised the importance of acuity reserve in determining the required magnification for optimum reading rate. Two different approaches have been proposed for the appropriate acuity reserve to use in calculating magnification. These are a fixed acuity reserve of 0.3 log unit or an individual determination of optimum acuity reserve. The aim of this study was to investigate the magnification and reading rates with low vision aids selected by the two methods. Methods : Nineteen low vision subjects with age‐related macular degeneration (AMD) who were experienced magnifier‐users were recruited. Reading rates and near VA with low vision aids determined by the fixed and individual acuity reserve methods were compared with the same measures made with the subjects' own magnifiers. Results : There were no significant differences in reading rate and near VA measured with low vision aids selected by either the fixed or individual acuity reserve methods or the subjects' own magnifiers. Reading rate with low vision aids was not significantly different from reading rate for large print with conventional near additions. Thus, for experienced users, magnifiers do not cause reduced reading rate. Conclusions : The fixed acuity reserve method is simple to apply as only near VA and print size of the target reading task are required. For the individual acuity reserve method, reading rates at different print sizes need to be measured. We recommend the use of a fixed acuity reserve (0.3 log unit) for the calculation of required magnification for low vision patients. If near VA or reading rate are not satisfactory with the magnification calculated by this method, individual assessment of required acuity reserve is necessary.     

Acute virulent infection with Plasmodium chabaudi does not impair the generation of a protective immune response

We have investigated whether a protective immune response occurred in mice infected with a virulent cloned strain of Plasmodium chabaudi. Animals inoculated intravenously with 10(7) parasitized erythrocytes (PE) showed an exponentially increasing parasitaemia and died by day 6 of the infection, presenting a pronounced anaemia. Smaller inocula produced a longer pre-patent period but did not change the lethal course of infection, since mice injected with 100 parasites died on day 12. When anaemia was compensated for by red blood cell (RBC) transfusion, infected mice recovered and thereafter exhibited a strong immunity, comparable to that of mice immunized by a drug-controlled infection. The immune response was P. chabaudi specific, as the mice were fully susceptible to a challenge by P. yoelii. Three transfusions of 5 x 10(9) RBC per mouse at 2-day intervals were necessary before all the animals were able to control the infection. Transfusion of a larger number of RBC resulted in a lower anaemia and a delay in reticulocytaemia but, paradoxically, the expression of the immune response was delayed. Three transfusions of 1.2 x 10(10) RBC enabled three out of eight mice to survive the infection, while six transfusions enabled all the mice to survive. The data suggest that parasitized immature RBC could play an important role in triggering the protective immune response.     

Dietary fat modulation of left ventricular ejection fraction in the marmoset due to enhanced filling.

OBJECTIVE: The aim was to investigate the influence of long term dietary fish oil consumption on cardiac function in a non-human primate, to elucidate further the basis of the apparently reduced cardiovascular disease mortality associated with its consumption in man. METHODS: Adult male marmoset monkeys (Callithrix jacchus) were fed diets supplemented with polyunsaturated fatty acids (PUFA) of marine (tuna fish oil) or plant (sunflower seed oil) origin, saturated animal fat (sheep perirenal fat), or a low fat reference diet for 24 months. Cardiac function was assessed using radionuclide angiography under pentobarbitone anaesthesia with a counts based adaptation for ventricular volume estimations. Measures were made at rest and during infusion of adrenaline. RESULTS: The mean left ventricular ejection fraction was greater in the tuna fish oil group [55.0(SEM 1.1)% n = 7] and the sunflower seed oil group [58.1(2.4)% n = 8] than in the reference group [48.5(1.4)% n = 9] and the sheep fat group [47.6(1.8)% n = 8]. This was associated with a more than 25% greater end diastolic volume and 40-70% increases in stroke volume in tuna fish or sunflower seed oil fed animals. There was no evidence of cardiac hypertrophy. In contrast, adrenaline increased stroke volume and ejection fraction by increasing emptying, thus reducing residual end systolic. Tuna fish oil fed animals had a low resting heart rate. When this was raised to comparable levels by adrenaline, lower pressure-rate indices and greater cardiac minute work suggested higher myocardial energy efficiency in PUFA fed animals compared with the reference and sheep fat groups. CONCLUSIONS: Dietary fish oil and sunflower seed oil increased the left ventricular ejection fraction in the marmoset monkey by enhancing ventricular filling, thus providing an energy sparing promotion of diastolic relaxation.     

Association between High Diffusion-Weighted Imaging-Derived Functional Tumor Burden of Peritoneal Carcinomatosis and Overall Survival in Patients with Advanced Ovarian Carcinoma

ObjectiveTo investigate the association between functional tumor burden of peritoneal carcinomatosis (PC) derived from diffusion-weighted imaging (DWI) and overall survival in patients with advanced ovarian carcinoma (OC).Materials and MethodsThis prospective study was approved by the local research ethics committee, and informed consent was obtained. Fifty patients (mean age ± standard deviation, 57 ± 12 years) with stage III–IV OC scheduled for primary or interval debulking surgery (IDS) were recruited between June 2016 and December 2021. DWI (b values: 0, 400, and 800 s/mm²) was acquired with a 16-channel phased-array torso coil. The functional PC burden on DWI was derived based on K-means clustering to discard fat, air, and normal tissue. A score similar to the surgical peritoneal cancer index was assigned to each abdominopelvic region, with additional scores assigned to the involvement of critical sites, denoted as the functional peritoneal cancer index (fPCI). The apparent diffusion coefficient (ADC) of the largest lesion was calculated. Patients were dichotomized by immediate surgical outcome into high- and low-risk groups (with and without residual disease, respectively) with subsequent survival analysis using the Kaplan-Meier curve and log-rank test. Multivariable Cox proportional hazards regression was used to evaluate the association between DWI-derived results and overall survival.ResultsFifteen (30.0%) patients underwent primary debulking surgery, and 35 (70.0%) patients received neoadjuvant chemotherapy followed by IDS. Complete tumor debulking was achieved in 32 patients. Patients with residual disease after debulking surgery had reduced overall survival (p = 0.043). The fPCI/ADC was negatively associated with overall survival when accounted for clinicopathological information with a hazard ratio of 1.254 for high fPCI/ADC (95% confidence interval, 1.007–1.560; p = 0.043).ConclusionA high DWI-derived functional tumor burden was associated with decreased overall survival in patients with advanced OC.     

Site Specific Delivery of Microencapsulated Fish Oil to the Gastrointestinal Tract of the Rat

The aim of this study was to design food grade matrices to deliver microencapsulated fish oil to the large bowel of the rat where the potential exists to retard inflammation and cancer development. Digestion in simulated gastric fluid and intestinal fluid demonstrated that only 4–6% of oil was released from the following dried emulsion formulations: 50% fish oil encapsulated in heated casein-glucose-dried glucose syrup (1:1:1) (Cas-Glu-DGS-50); 25% fish oil in casein-modified resistant starch (Hylon VII) (1:1) (Cas-Hylon-25); or 25% fish oil in Cas-Glu-Hylon (1:1:1) (Cas-Glu-Hylon-25). A short-term gavage study (0–12 h) with fish oil and Cas-Glu-DGS-50 demonstrated the appearance of fish oil long chain (LC) n-3 polyunsaturated fatty acids (PUFA) into the plasma indicating specific small intestinal absorption with little LC n-3 PUFA reaching the large bowel. In a 2-week-long term, daily gavage study, the bioavailability of fish oil and fish oil in Cas-Glu-DGS-50 or Cas-Hylon-25 demonstrated that fish oil and Cas-Glu-DGS-50 LC n-3 PUFA were incorporated into the tissue of the small intestine and colon, whereas Cas-Hylon-25 was resistant to degradation in the small intestine. The use of modified Hylon VII for targeted colonic delivery was confirmed in the final short-term gavage study (0–14 h) using Cas-Glu-Hylon-25 with [¹⁴C]-trilinolenin as a marker incorporated into the microcapsules, where up to 60% of the labeled oil reached the large bowel. Depending on the microencapsulating matrix employed, fish oil can be delivered selectively to the small intestine or to a high degree to the large bowel.