Immunohistological detection of Legionella pneumophila in lung sections.

Immunohistology was used for the detection of Legionella pneumophila serogroup I in necropsy tissue. Study of pneumonic lung from the recent Stafford outbreak has shown that this technique has a high sensitivity. A retrospective postmortem examination showed that L pneumophila serogroup 1 was an unusual cause of pneumonia in Oxfordshire during the study period. L pneumophila serogroup 1 can be successfully subgrouped, using a panel of monoclonal antibodies on formalin fixed paraffin embedded sections. Immunohistological methods have a potentially useful role in the diagnosis of Legionellosis at postmortem examination and in the epidemiological investigation of individual cases and outbreaks.     

Cellular immunity in Peyer''s patches of rats infected with Trichinella spiralis.

A rat model of Trichinella spiralis gut infection was used to observe the sequence of developing cellular immunity in Peyer's patches and other lymphoid tissues. Whereas cellular reactivity (lymphocyte blastogenesis) for worm antigens was evident in mesenteric lymph nodes draining the gastrointestinal tract within 3 days after infection, Peyer's patch lymphocytes developed maximal reactivity 2 to 3 weeks later at the same time as the spleen and other lymphoid tissues. Furthermore, the immune reactivity found in Peyer's patches was only transient. Thus, in this parasitic gut infection, the Peyer's patch lymphoid tissue does not appear to be the first site of cellular responsiveness but rather to acquire cellular reactivity only when other lymphoid elements in the infected host have also acquired similar antigen-induced reactivity.     

Renin and angiotensin-like levels in foetal, new-born and adult sheep

1. Plasma renin (measured as rate of formation of angiotensin I ng/ml.hr(-1) in the presence of added substrate at pH 7.5 and 37 degrees C) was much lower in recently nephrectomized foetal, new-born and older lambs than in intact siblings or other similar lambs.2. Angiotensin II-like concentrations were measured using a superfusion technique in an extracorporeal circuit. Resting concentrations in acute experiments under anaesthesia were deduced by comparison of carotid blood of intact lambs with that from recently nephrectomized lambs.3. Angiotensin II-like activity (mean +/- S.E. of mean, 315 +/- 117 pg/ml.) was readily detectable in foetal blood at 123-138 days gestation. The highest concentrations (mean +/- S.E. of mean 839 +/- 96 pg/ml.) were found in lambs less than 8 hr old, delivered vaginally. The lowest concentrations of angiotensin II-like activity occurred in lambs delivered by Caesarean section (mean +/- S.E. of mean < 123 +/- 12 pg/ml.). Concentrations declined with post-natal age.4. Hypovolaemia as a result of haemorrhage evoked an increase in angiotensin II-like concentrations in foetus, new-born lambs and adult sheep. The greatest increase of angiotensin-like concentrations was seen in new-born lambs. This rise was associated with increase of plasma renin.5. The rise of arterial pressure during bilateral carotid occlusion in new-born lambs was accompanied by an increase of angiotensin II-like concentration.6. It is concluded that the renin-angiotensin system is functional and can be stimulated during intra-uterine life. The increase of angiotensin II-like concentration following parturition is probably transient and associated with the trauma of delivery. This contrasts with observations made in the rabbit which suggest that full functional maturity of the renin angiotensin system is delayed until the second week of life.     

Olfactory bulb removal affects partner preference development and estrus induction in female prairie voles.

In female prairie voles (Microtus ochrogaster) bilateral olfactory bulbectomy reduced affiliative behavior, as measured by social contact, and prevented the formation of partner preferences. Unilateral olfactory bulb removal did not significantly influence affiliative behavior, but did inhibit partner preferences. Bilateral, but not unilateral, bulbectomy significantly reduced the proportion of females exhibiting behavioral estrus following male exposure. In contrast to affiliative and sexual behavior, parental behavior was not significantly affected by either bilateral or unilateral olfactory bulbectomy. These results suggest that divergent sensory-neural pathways underlie social, sexual, and parental behaviors in this species.     

Morphology of cardiac muscle in septic shock. Observations with a porcine septic shock model

The morphology of cardiac muscle was investigated in a porcine model of septic shock, created by intermitted application of Escherichia coli-endotoxin. The earliest lesions, found after 18 h of septic shock, were endothelial cell swelling, marked leucostasis and slight ischaemic alterations of the muscle fibres. At the end point of the experiments, after 48 h, some fibrin thrombi were found associated with more pronounced ischaemic alterations of cardiac muscle cells and some necrotic fibres. Comparing these findings with the severe endothelial and muscle fibre lesions found in skeletal muscle, the endothelial cells of the heart microvasculature, are clearly more resistant to the attack of the endotoxins and mediators liberated in septic shock.     

A photoetched cell relocation matrix for long-term, quantitative observations of selected individual neurons in culture

A photoetched matrix of indium tin oxide (ITO) on glass has been developed and tested as a tool to assist in the relocation and identification of individual neuronal cells in culture. The matrix is formed by 10-15 micron wide and 300 A thick ITO lines which subdivide a 1-cm2 area into 625 smaller squares. Each of the smaller squares measures 400 micron on a side and contains a photoetched two-letter "address". The address code allows precise relocation of specific regions of a culture as well as verification of the identities of individual neurons selected for repeated observation. Marks at 50 micron intervals along the sides of the address squares permit quantitative analysis of morphological changes, cell migration, reaggregation, etc. The ITO is transparent and does not interfere with visualization of even fine details of cells with high power microscopy.     

Swine flu vaccine and multiple sclerosis

Using age-specific rates for multiple sclerosis (MS) based on a national survey, the number of "naturally occurring" new cases of MS among the 45 million swine flu vaccine recipients in the United States is estimated as 1,624 during the year after vaccination, or 31 cases per week. Information from available reports and publications indicates no excess over the expected frequencies. Analyses of admissions for MS before, during, and after the immunization program showed no increase to the US Army hospitals or to the Mayo Clinic. Three independent controlled clinical investigations performed on patients with MS showed no increase in the frequency of exacerbations among those receiving swine flu vaccine as compared with those receiving placebo. Epidemiologic features of MS do not implicate killed virus vaccine as an etiologic factor in onset or exacerbations of the disease. There is no indication from these analyses of any association or cause-and-effect relationship between swine flu vaccine and MS.     

Food insecurity among Canadian youth and young adults: insights from the Canada Food Study

ObjectiveThis study explored associations between socio-demographic characteristics, self-reported health, and household food security among young adults.MethodsNational cohort study participants from Toronto, Montreal, Vancouver, Edmonton, and Halifax, Canada, aged 16–30 years (n = 2149) completed online surveys. Multinomial logistic regression, weighted to reflect age and sex proportions from the 2016 census, was conducted to examine associations between food security status and covariates.ResultsAlmost 30% of respondents lived in food-insecure households, with 19% in “moderately” food-insecure and 10% in “severely” food-insecure households. Respondents identifying as Black or Indigenous were more likely to live in moderately (AOR = 1.96, CI: 1.10, 3.50; AOR = 3.15, CI: 1.60, 6.20) and severely (AOR = 4.25, CI: 2.07, 8.74; AOR = 6.34, CI: 2.81, 14.30) food-insecure households compared with those identifying as mixed/other ethnicity. Respondents who found it “very difficult” to make ends meet were more likely to be moderately (AOR = 20.37, CI: 11.07, 37.46) and severely (AOR = 101.33, CI: 41.11, 249.77) food insecure. Respondents classified as “normal” weight (AOR = 0.64, CI: 0.43, 0.96) or overweight (AOR = 0.53, CI: 0.34, 0.83) were less likely to be moderately food insecure compared with those affected by obesity. Compared with “very good or excellent,” “poor” health, diet quality, and mental health were each positively associated with severe food insecurity (AOR = 7.09, CI: 2.44, 20.61; AOR = 2.63, CI: 1.08, 6.41; AOR = 2.09, CI: 1.03, 4.23, respectively).ConclusionThe high prevalence of correlates of food insecurity among young adults suggests the need for policies that consider the unique challenges (e.g., precarious income) and vulnerability associated with this life stage.     

Exploring the main and moderating effects of individual-level characteristics on consumer responses to sugar taxes and front-of-pack nutrition labels in an experimental marketplace

InterventionThis study examined whether the impacts of sugar taxes and front-of-pack (FOP) nutrition labels differ across socio-demographic subgroups.Research questionWhat are the main and moderating effects of individual-level characteristics on the nutrient content of participants’ purchases in response to varying taxation levels and FOP labels?MethodsData from an experimental marketplace were analyzed. A sample of 3584 Canadians aged 13 years and older received $5 to purchase an item from a selection of 20 beverages and 20 snack foods. Participants were shown products with one of five FOP labels and completed eight within-subject purchasing tasks with different tax conditions. Linear mixed models were used to estimate the main and moderating effects of 11 individual-level variables on the sugars, sodium, saturated fats, and calorie content of participants’ purchases.ResultsParticipants who were younger, male, and more frequent consumers of sugary drinks purchased products containing more sugars, sodium, saturated fats, and calories. Sex and age moderated the relationship between tax condition and sugars or calories purchased: female participants were more responsive than males to a tax that included fruit juice, and younger participants were more responsive to all sugar tax conditions than older participants. Reported thirst and education level also moderated the relationship between tax condition and calories purchased. No individual-level characteristics moderated the effects of FOP labels.ConclusionA small proportion (7 of 176) of the moderating effects tested in this study were significant. Sugar taxes and FOP labelling policies may therefore produce similar effects across key socio-demographic groups.Supplementary InformationThe online version contains supplementary material available at 10.17269/s41997-021-00475-x.