Isolation, characterization, and in vitro evaluation of bovine rumen submucosa films of collagen or chitosan-treated collagen

Bovine rumen is hitherto considered as an inedible waste of meat industry. The rumen tissues can be used as an alternative source of collagen to produce biocompatible materials for clinical application. In an effort to develop a functional biomaterial from the inedible mammalian tissues, this study aims to isolate and characterize bovine rumen submucosa. Initially, the rumen tissue was sequentially processed using chemical and enzymatic treatment to decellularize, neutralize, stabilize, and to produce a native collagen matrix which is referred as collagen film (COL-F). Thus, prepared matrix was treated with 1% (w/v) chitosan solution to produce a hybrid film which is referred as collagen–chitosan film (COL/CS-F). The comparative study includes the evaluation of physical, chemical, and biological properties of the biofilms prepared. The surface topology of COL-F exhibited a continuous collagenous network with fibrous nature, while the chitosan treatment provided smooth plain surface to the parent film. Incorporation of chitosan in COL-F increased the tensile properties, as well as the thermal stability and durability of the films. The Fourier Transform Infrared spectroscopy results revealed the presence of respective amide peaks, which corresponds to protein (collagen), and the evidence of collagen–chitosan interlinking. The submucosa layer was electrophoretically found to have type I collagen. The X-ray diffraction data showed the presence of amorphous and crystalline peak which attributes to the triple helical structure of collagen in the films. Cytotoxicity studies on the films were performed in vitro using human keratinocytes. The results of cell viability and proliferation demonstrated that COL-F and COL/CS-F exhibit good biocompatibility and therefore can augment cell infiltration and proliferation. However, enhanced cellular activity was observed on the chitosan treated COL-F. These observations demonstrate that the biofilms prepared in this study can be used as an alternative functional biomaterial in tissue engineering.

Timing of antiretroviral therapy initiation in a nationally representative sample of HIV-infected adults receiving medical care in the United States

Early antiretroviral therapy (ART) initiation reduces the risk of disease progression and HIV transmission, but data on time from HIV care entry to ART initiation are lacking. Using data from the Medical Monitoring Project (MMP), a population-based probability sample of HIV-infected adults receiving medical care in the United States, we assessed time from care entry to ART initiation among persons diagnosed May 2004-April 2009 and used multivariable Cox proportional-hazards models to identify factors associated with time to ART initiation. Among 1094 MMP participants, 83.9% reported initiating ART, with median time to ART initiation of 10 months. In multivariable models, blacks compared to whites [hazard ratio (HR) 0.82; 95% confidence interval (CI) 0.70-0.98], persons without continuous health insurance (HR 0.82; CI 0.70-0.97), heterosexual women and men who have sex with men compared to heterosexual men (HR 0.66; CI 0.51-0.85 and HR 0.71; CI 0.60-0.84, respectively), and persons without AIDS at care entry (HR 0.37; CI 0.31-0.43) had significantly longer times to ART initiation. Overall, time to ART initiation was suboptimal by current standards and significant disparities were noted among certain subgroups. Efforts to encourage prompt ART initiation should address delays among those without health insurance and among certain sociodemographic subgroups.

[Childhood granulomatous periorificial dermatitis]

CASE REPORT

A 14-year-old patient of African ancestry presented with multiple papules in the perioral, perinasal and periocular areas. Histopathology showed sarcoidal granulomas.

DIAGNOSIS

After exclusion of systemic sarcoidosis, the diagnosis of childhood granulomatous periorificial dermatitis was made.

THERAPY

Topical treatment with erythromycin resulted in complete regression.

CONCLUSION

Childhood granulomatous periorificial dermatitis is mainly observed in dark-skinned children of African, Caribbean, or Asian origin. The nosological position of the dermatosis is controversial. Originally classified as sarcoidosis, childhood granulomatous periorificial dermatitis is now generally regarded as a special form of perioral dermatitis.

Bone mineral density changes among HIV-uninfected young adults in a randomised trial of pre-exposure prophylaxis with tenofovir-emtricitabine or placebo in Botswana

BACKGROUND

Tenofovir-emtricitabine (TDF-FTC) pre-exposure prophylaxis (PrEP) has been found to be effective for prevention of HIV infection in several clinical trials. Two studies of TDF PrEP among men who have sex with men showed slight bone mineral density (BMD) loss. We investigated the effect of TDF and the interaction of TDF and hormonal contraception on BMD among HIV-uninfected African men and women.

METHOD

We evaluated the effects on BMD of using daily oral TDF-FTC compared to placebo among heterosexual men and women aged 18-29 years enrolled in the Botswana TDF2 PrEP study. Participants had BMD measurements at baseline and thereafter at 6-month intervals with dual-energy X-ray absorptiometry (DXA) scans at the hip, spine, and forearm.

RESULTS

A total of 220 participants (108 TDF-FTC, 112 placebo) had baseline DXA BMD measurements at three anatomic sites. Fifteen (6.8%) participants had low baseline BMD (z-score of <-2.0 at any anatomic site), including 3/114 women (2.6%) and 12/106 men (11.3%) (p = 0.02). Low baseline BMD was associated with being underweight (p = 0.02), having high blood urea nitrogen (p = 0.02) or high alkaline phosphatase (p = 0.03), and low creatinine clearance (p = 0.04). BMD losses of >3.0% at any anatomic site at any time after baseline were significantly greater for the TDF-FTC treatment group [34/68 (50.0%) TDF-FTC vs. 26/79 (32.9%) placebo; p = 0.04]. There was a small but significant difference in the mean percent change in BMD from baseline for TDF-FTC versus placebo at all three sites at month 30 [forearm -0.84% (p = 0.01), spine -1.62% (p = 0.0002), hip -1.51% (p = 0.003)].

CONCLUSION

Use of TDF-FTC was associated with a small but statistically significant decrease in BMD at the forearm, hip and lumbar spine. A high percentage (6.8%) of healthy Batswana young adults had abnormal baseline BMD Further evaluation is needed of the longer-term use of TDF in HIV-uninfected persons.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00448669.

HIV testing and risk behaviors among gay, bisexual, and other men who have sex with men - United States

The burden of human immunodeficiency virus (HIV) is high among gay, bisexual, and other men who have sex with men (MSM). High HIV prevalence, lack of awareness of HIV-positive status, unprotected anal sex, and increased viral load among HIV-positive MSM not on antiretroviral treatment contribute substantially to new infections among this population. CDC analyzed data from the National HIV Surveillance System (NHSS) to estimate the percentage of HIV diagnoses among MSM by area of residence and data from the National HIV Behavioral Surveillance System (NHBS) to estimate unprotected anal sex in the past 12 months among MSM in 2005, 2008, and 2011; unprotected discordant anal sex at last sex (i.e., with a partner of opposite or unknown HIV status) in 2008 and 2011; and HIV testing history and the percentage HIV-positive but unaware of their HIV status by the time since their last HIV test in 2011. This report describes the results of these analyses. In all but two states, the majority of new HIV diagnoses were among MSM in 2011. Unprotected anal sex at least once in the past 12 months increased from 48% in 2005 to 57% in 2011 (p<0.001). The percentage engaging in unprotected discordant anal sex was 13% in 2008 and 2011. In 2011, 33% of HIV-positive but unaware MSM reported unprotected discordant anal sex. Among MSM with negative or unknown HIV status, 67% had an HIV test in the past 12 months. Among those tested recently, the percentage HIV-positive but unaware of their infection was 4%, 5%, and 7% among those tested in the past ≤3, 4-6, and 7-12 months, respectively. Expanded efforts are needed to reduce HIV risk behaviors and to promote at least annual HIV testing among MSM.

The survival benefit of kidney transplantation in obese patients

Obese patients have a decreased risk of death on dialysis but an increased risk of death after transplantation, and may derive a lower survival benefit from transplantation. Using data from the United States between 1995 and 2007 and multivariate non-proportional hazards analyses we determined the relative risk of death in transplant recipients grouped by body mass index (BMI) compared to wait-listed candidates with the same BMI (n = 208 498). One year after transplantation the survival benefit of transplantation varied by BMI: Standard criteria donor transplantation was associated with a 48% reduction in the risk of death in patients with BMI ≥ 40 kg/m(2) but a ≥ 66% reduction in patients with BMI < 40 kg/m2. Living donor transplantation was associated with ≥ 66% reduction in the risk of death in all BMI groups. In sub-group analyses, transplantation from any donor source was associated with a survival benefit in obese patients ≥ 50 years, and diabetic patients, but a survival benefit was not demonstrated in Black patients with BMI ≥ 40 kg/m(2). Although most obese patients selected for transplantation derive a survival benefit, the benefit is lower when BMI is ≥ 40 kg/m(2), and uncertain in Black patients with BMI ≥ 40 kg/m(2).

Quantification of the early risk of death in elderly kidney transplant recipients

To inform decision making regarding transplantation in patients ≥ 65 years, we quantified the early posttransplant risk of death by determining the time to equal risk and equal survival between transplant recipients and wait-listed dialysis patients in the United States between 1995 and 2007 (total n = 25 468). Survival was determined using separate multivariate nonproportional hazards analyses in low-, intermediate- and high-risk cardiovascular risk patients. Compared to wait-listed patients with similar cardiovascular risk, standard criteria (SCD) and expanded criteria (ECD) recipients had a higher risk of death in the perioperative and early-posttransplant period. In contrast, low and intermediate risk living donor (LD) recipients had an immediate survival advantage compared to similar risk wait-listed patients. In all risk groups, transplantation was associated with a long-term survival advantage compared to dialysis, but there were marked differences in time to equal risk of death, and time to equal survival by donor type. For example, survival in high-risk recipients of an LD, SCD and ECD transplant became equal to that in similar risk wait-listed patients 130, 368 and 521 days after transplantation. Early posttransplant mortality risk is eliminated in low- and intermediate-risk patients, and markedly reduced in high-risk patients with LD transplantation.