The origin, kinetics, and characteristics of the kupffer cells in the normal steady state

Enzymatic digestion with pronase and DNAase was used to isolate Kupffer cells from mouse liver. The characteristics of these cells were found to be similar to those of peritoneal macrophages, except that in the initial suspension the percentage of Kupffer cells with Fc receptors was low, C receptors were absent and the ingestion of opsenized bacteria was very poor, because of the effect of pronase on the cell membrane. After 24 h incubation in vitro all these characteristics return. The in vitro and 1 h-pulse [(3)H]thymidine labeling of the Kupffer cells is low (0.8 and 1 percent, respectively) indicating that in essence these cells do not divide. It was also shown that the small percentage of in vitro labeled Kupffer cells was recently derived from the circulation. After an intravenous injection of zymosan the in vitro labeling index of the Kupffer cells increased 16-fold, but it was proven that these dividing cells were immature mononuclear phagocytes very recently recruited from the bone marrow. The labeling of Kupffer cells aider one or four injections of [(3)H]thymidine reached a peak of 10.4 percent at 48 h or 24.1 percent at 60 h, respectively, indicating that these cells are derived from labeled monocytes. Further evidence for this conclusion was obtained by the absence of an increase of labeled Kupffer cells during treatment with hydrocortisone, which causes a monocytopenia during which no circulating monocytes are available to migrate to the tissues. Labeling studies in animals X-irradiated with hind-limb shielding gave a Kupffer cell labeling index of 5-10 percent of the normal values, which confirms their bone marrow origin. A quantitative study on the production of labeled monocytes in the bone marrow and their transit through the circulation showed that in the normal steady state at least 56.4 percent of the monocytes leaving the circulation become Kupffer cells. Considering the Kupffer cells as kinetically homogeneous this gives a mean turnover time of the total population of Kupffer cells of 21 days.     

Predictors of smoking cessation and maintenance

A follow-up study of 263 volunteers who had completed a national smoking cessation program was conducted to measure the relative contribution of stress coping resources, smoking history, loci for health control, and certain demographic factors to the maintenance of smoking cessation. Stress coping resources and smoking history variables proved to be more predictive of the maintenance of abstinence than either perceived locus of control or demographic variables. Coping resources in the forms of perceived confidence, physical health, physical fitness, problem solving, self-directedness, and tension control were useful in predicting abstinence maintenance. Contrary to some earlier studies, no gender differences in relapse rates were found, and smoking a greater number of cigarettes daily and smoking cigarettes with a higher tar content were related to greater success in maintaining smoking abstinence. As was found in previous studies, the presence of other smokers in the household contributed to relapse. © 1998 John Wiley & Sons, Inc. J Clin Psychol 54: 223–235, 1998.     

Associations of gender identity with sexual behaviours,social stigma and sexually transmitted infections among adults who have sex with men in Abuja and Lagos,Nigeria

IntroductionSexual and gender minority populations are disproportionately affected by the global syndemic of HIV and other sexually transmitted infections (STIs). We hypothesized that transgender women (TGW) and non‐binary individuals in Nigeria have more STIs than cis‐gender men who have sex with men (cis‐MSM), and that experiences of stigma and sexual practices differ between these three groups.MethodsFrom 2013 to 2020, TRUST/RV368 enrolled adults assigned male sex at birth who reported anal sex with men in Abuja and Lagos, Nigeria. Participants were tested for STIs and completed questionnaires about sexual behaviours and social stigma every 3 months. Participants were categorized as cis‐MSM, TGW or non‐binary/other based on self‐reported gender identity. Gender group comparisons were made of HIV, gonorrhoea and chlamydia prevalence and incidence; stigma indicators; and condom use during anal sex.ResultsAmong 2795 participants, there were 2260 (80.8%) cis‐MSM, 284 (10.2%) TGW and 251 (9.0%) non‐binary/other individuals with median age of 23 years (interquartile range 20–27). HIV prevalence among cis‐MSM, TGW and non‐binary/other participants was 40.8%, 51.5% and 47.6%, respectively (p = 0.002). HIV incidence was 8.7 cases per 100 person‐years (PY) (95% confidence interval [CI] 6.9–10.8), 13.1 cases/100 PY (95% CI 6.5–23.4) and 17.6 cases/100 PY (95% CI 9.8–29.0, p = 0.025), respectively. Anorectal gonorrhoea incidence was lower in cis‐MSM than TGW (22.2 [95% CI 19.6–25.0] vs. 35.9 [95% CI 27.3–46.3]). TGW were more likely than cis‐MSM to report being affected by stigma, including assault (47.2% vs. 32.3%), fear of walking around (32.4% vs. 19.2%) and healthcare avoidance (25.0% vs. 19.1%; all p < 0.05). TGW were more likely to report always using condoms than non‐binary/other individuals (35.3% vs. 26.2%, p = 0.041) during receptive anal sex.ConclusionsSexual and gender minorities in Nigeria have heterogeneous sexual behaviours and experiences of social stigma that may influence the vulnerability to HIV and other STIs. There is a need for tailored interventions that acknowledge and are informed by gender. Further research is needed, particularly among understudied non‐binary individuals, to better understand disparities and inform tailored interventions to improve outcomes among these communities.     

A spatial approach for the epidemiology of antibiotic use and resistance in community-based studies: the emergence of urban clusters of <Emphasis Type="Italic">Escherichia coli</Emphasis> quinolone resistance in Sao Paulo,Brasil

Background  

Population antimicrobial use may influence resistance emergence. Resistance is an ecological phenomenon due to potential transmissibility. We investigated spatial and temporal patterns of ciprofloxacin (CIP) population consumption related to E. coli resistance emergence and dissemination in a major Brazilian city. A total of 4,372 urinary tract infection E. coli cases, with 723 CIP resistant, were identified in 2002 from two outpatient centres. Cases were address geocoded in a digital map. Raw CIP consumption data was transformed into usage density in DDDs by CIP selling points influence zones determination. A stochastic model coupled with a Geographical Information System was applied for relating resistance and usage density and for detecting city areas of high/low resistance risk.     

Rosuvastatin protects against podocyte apoptosis in vitro

BACKGROUND: Clinical studies suggest that statins reduce proteinuria and slow the decline in kidney function in chronic kidney disease. Given a rich literature identifying podocyte apoptosis as an early step in the pathophysiological progression to proteinuria and glomerulosclerosis, we hypothesized that rosuvastatin protects podocytes from undergoing apoptosis. Regarding a potential mechanism, our lab has shown that the cell cycle protein, p21, has a prosurvial role in podocytes and there is literature showing statins upregulate p21 in other renal cells. Therefore, we queried whether rosuvastatin is prosurvival in podocytes through a p21-dependent pathway. METHODS: Two independent apoptotic triggers, puromycin aminonucleoside (PA) and adriamycin (ADR), were used to induce apoptosis in p21 +/+ and p21 -/- conditionally immortalized mouse podocytes with or without pre-exposure to rosuvastatin. Apoptosis was measured by two methods: Hoechst 33342 staining and fluorescence-activated cell sorting (FACS). To establish a role for p21, p21 levels were measured by western blotting following rosuvastatin exposure and p21 was stably transduced into p21 -/- mouse podocytes. RESULTS: Rosuvastatin protects against ADR- and PA-induced apoptosis in podocytes. Further, exposure to rosuvastatin increases p21 levels in podocytes in vitro. ADR induces apoptosis in p21 -/- mouse podocytes, but rosuvastatin's protective effect is not seen in the absence of p21. Reconstituting p21 in p21 -/- podocytes restores rosuvastatin's prosurvival effect. CONCLUSION: Rosuvastatin is prosurvival in injured podocytes. Rosuvastatin exerts its protective effect through a p21-dependent antiapoptotic pathway. These findings suggest that statins decrease proteinuria by protecting against podocyte apoptosis and subsequent podocyte depopulation.