A mathematical simulation of the AIDS patient and extracorporeal detoxification

A simple numerical simulation of AIDS patient detoxification by a hypothetical extracorporeal device for the removal of viruses, infected white cells, and syncytia has been designed. The mathematical model accounts for healthy blood white cells attacking and destroying the viruses, while at the same time the viruses attack and infect certain white cells. The infected white cells serve as a site for viral growth; eventually the cells lyse, releasing a large number of viruses into the blood stream. The healthy white cells and infected white cells combine to form syncytia, where the virus multiplies, and finally the syncytium ruptures releasing all the virus. This model can be used to predict concentrations over a specified period for the patient. This is a mathematical model to be used as a research and design tool only.     

Transient association between semen exposure and biomarkers of genital inflammation in South African women at risk of HIV infection

IntroductionSemen induces mucosal changes in the female reproductive tract to improve pregnancy outcomes. Since semen‐induced alterations are likely short‐lived and genital inflammation is linked to HIV acquisition in women, we investigated the contribution of recent semen exposure on biomarkers of genital inflammation in women at high HIV risk and the persistence of these associations.MethodsWe assessed stored genital specimens from 152 HIV‐negative KwaZulu‐Natal women who participated in the CAPRISA 008 trial between November 2012 and October 2014. During the two‐year study period, 651 vaginal specimens were collected biannually (mean five samples per woman). Cervicovaginal lavage (CVL) was screened for prostate‐specific antigen (PSA) by ELISA, whereas Y‐chromosome DNA (YcDNA) detection and quantification were conducted by RT‐PCR, representing semen exposure within 48 hours (PSA+YcDNA+) and semen exposure within three to fifteen days (PSA−YcDNA+). Soluble protein concentrations were measured in CVLs by multiplexed ELISA. T‐cell frequencies were assessed in cytobrushes by flow‐cytometry, and vulvovaginal swabs were used to detect common vaginal microbes by PCR. Linear mixed models adjusting for factors associated with genital inflammation and HIV risk were used to assess the impact of semen exposure on biomarkers of inflammation over multiple visits.ResultsHere, 19% (125/651) of CVLs were PSA+YcDNA+, 14% (93/651) were PSA−YcDNA+ and 67% (433/651) were PSA−YcDNA−. Semen exposure was associated with how often women saw their partners, the frequency of vaginal sex in the past month, HSV‐2 antibody detection, current gonorrhoea infection and Nugent Score. Both PSA detection (PSA+YcDNA+) and higher cervicovaginal YcDNA concentrations predicted increases in several cytokines, barrier‐related proteins (MMP‐2, TIMP‐1 and TIMP‐4) and activated CD4+CCR5+HLA‐DR+ T cells (β = 0.050; CI 0.001 to 0.098; p = 0.046) and CD4+HLA‐DR+ T cells (β = 0.177; CI 0.016 to 0.339; p = 0.032) respectively. PSA detection was specifically associated with raised pro‐inflammatory cytokines (including IL‐6, TNF‐α, IP‐10 and RANTES), and with the detection of BVAB2 (OR = 1.755; CI 1.116 to 2.760; p = 0.015), P. bivia (OR = 1.886; CI 1.102 to 3.228; p = 0.021) and Gardnerella vaginalis (OR = 1.815; CI 1.093 to 3.015; p = 0.021).ConclusionsMore recent semen exposure was associated with raised levels of inflammatory biomarkers and the detection of BV‐associated microbes, which declined by three to fifteen days of post‐exposure. Although transient, semen‐induced alterations may have implications for HIV susceptibility in women.     

The pharmacokinetics of high-dose epirubicin and of the cardioprotector ADR-529 given together with cyclophosphamide, 5-fluorouracil,and tamoxifen in metastatic breast-cancer patients

A high-pressure liquid chromatographic method for determination of the bisdioxopiperazine derivative ADR-529 (ICRF-187), a compound proven effective in protection against anthracycline-induced cardiotoxicity, has been developed. The limit of quantitation was 5 ng/ml using a narrow-bore 5-m silica column and UV detection. The method was used for determination of pharmacokinetic profiles of ADR-529 after a 3-weekly i.v. administration of different doses of ADR-529 (600–1000 mg/m²) together with different doses of epirubicin (E, 60–100 mg/m²), fixed-dose cyclophosphamide (C, 600 mg/m²), fixed-dose 5-fluorouracil (F, 600 mg/m²), and daily administration of tamoxifen (T, 30 mg; CEF-T) in the treatment of patients with metastatic breast cancer. Pharmacokinetic parameters for epirubicin were also determined. The aim of the study was to determine (1) whether the pharmacokinetics of ADR-529 as part of a combination with CEF-T changes with increasing doses of ADR-529 and increasing doses of epirubicin and (2) whether the pharmacokinetics of epirubicin in the same combinations is altered with the administration of increasing doses of ADR-529. A total of 82 patients were included. A crossover study including 16 of the patients showed no significant difference in epirubicin pharmacokinetic parameters when epirubicin was given with or without concomitant administration of ADR-529. Apart from minor changes in the distributional half-lives, the pharmacokinetic parameters of epirubicin were not altered with increasing doses of ADR-529, nor were the pharmacokinetic parameters of ADR-529 itself. Escalating doses of epirubicin did not significantly alter the pharmacokinetic parameters of ADR-529 with the exception of a 30% increase in the terminal half-life and a decrease in total body clearance when the epirubicin dose was raised from 60 to 100 mg/m². We conclude that concomitant administration of ADR-529 does not alter the distribution and elimination of epirubicin in doses suitable for preventing the anthracycline-induced cardiotoxicity.     

Diabetes in New Zealand--better information needed.

AIMS: To review the availability and quality of data on the epidemiology of diabetes in New Zealand. METHODS: A search was undertaken for all Medline-indexed publications on diabetes in New Zealand. Hospitalisation and mortality data (ICD9 code 250) from the New Zealand Health Information Service (NZHIS) were examined. RESULTS: Information on diabetes in New Zealand has come from community surveys, national surveys, diabetes registers, hospitalisation data and mortality data. Much of this information has been valuable, but there is still inadequate national information on diabetes prevalence, incidence and time trends. CONCLUSION: Information technology provides an opportunity to couple the surveillance of diabetes with improved diabetes care. Medical practitioners need to support the development of their own practice-based registers/recall systems and to contribute to the development of district-based diabetes registers where these have a central focus on improving diabetes care.     

Cellular uptake and concentrations of tamoxifen upon administration in poly(ε-caprolactone) nanoparticles

Purpose: In an attempt to increase the local concentration of tamoxifen in estrogen receptor positive breast cancer cells, we have prepared and characterized poly (ε-caprolactone) (PCL) nanoparticle formulation. Methods: PCL (mol wt 14,800 daltons) nanoparticles were prepared by the solvent displacement method in acetonewater system in the presence of Pluronic F-68. PCL nanoparticles, labeled with rhodamine 123, were incubated with MCF-7 estrogen receptor positive breast cancer cells to determine uptake, intracellular distribution, and localization as a function of time. Intracellular drug concentrations over a specified period of time using different initial doses were examined using tritiated [³H]-tamoxifen. Results: A significant fraction of the administered rhodamine 123-loaded PCL nanoparticles was found in the perinuclear region of the MCF-7 cells, where estrogen receptors are also localized, after 1 hour of incubation. Measurements of the intracellular concentrations revealed that most of the administered nanoparticle dose was internalized within the first 30 minutes of incubation, and the uptake followed saturable transport kinetics. Conclusion: Results of this study show that PCL nanoparticles were rapidly internalized in MCF-7 cells and intracellular tamoxifen concentrations followed a saturable process. This approach may provide better therapeutic benefit by delivering the drug locally, near the tumor cells, for a longer period of time.     

Phase I/IIa study of cetuximab with gemcitabine plus carboplatin in patients with chemotherapy-naive advanced non-small-cell lung cancer.

PURPOSE: This multicenter, open-label, phase I/IIa study was undertaken to establish the safety/toxicity profile of cetuximab in combination with gemcitabine and carboplatin in patients with chemotherapy-na?ve, epidermal growth factor receptor-positive, stage IV non-small-cell lung cancer. Secondary objectives were to gather preliminary evidence of efficacy including tumor response rate, time to progression, and overall survival. PATIENTS AND METHODS: Thirty-five patients received a total of 264 3-week cycles of treatment with cetuximab, carboplatin, and gemcitabine. An initial dose of cetuximab 400 mg/m2 intravenously was administered the first week, followed by weekly doses of 250 mg/m2. Carboplatin (area under the curve = 5, day 1) and gemcitabine 1,000 mg/m2 on days 1 and 8 were administered every 3 weeks. Patients were evaluated for tumor response after every two cycles of therapy. RESULTS: The most frequently reported adverse events related to cetuximab included an acne-like rash (88.6%), dry skin (34.3%), asthenia and skin disorders (31.4%), mucositis/stomatitis (25.7%), fever/chills (20%), and nausea/vomiting (17.1%). The majority of these toxicities were mild to moderate. One patient withdrew from the study because of a grade 3 allergic reaction. Myelosuppression was the most frequently observed toxicity related to chemotherapy. Responses among 35 assessable patients included 10 partial responses (28.6%). Twenty-one patients had stable disease. The median time to progression was 165 days, and the median overall survival was 310 days. CONCLUSION: The combination of cetuximab, carboplatin, and gemcitabine was well tolerated with an acceptable toxicity profile. Most grade 3 adverse events were attributable to chemotherapy. The response rate and median survival are encouraging and warrant additional investigation.     

Metabolism of retinoids and arachidonic acid by human and mouse cytochrome P450 1b1.

The cytochrome P450 family 1 (CYP1) is considered to be one of the xenobiotic-metabolizing enzyme families and is responsible for oxidative metabolism of polycyclic aromatic hydrocarbons. For example, mouse Cyp1b1 was originally identified as the enzyme responsible for oxidative metabolism of 7,12-dimethylbenz(alpha)anthracene (DMBA). A comparison of the kinetics of this metabolism by mouse and human CYP1B1 orthologs revealed the mouse enzyme to have a more favorable metabolism of DMBA, with a catalytic efficiency ratio (CER) of 0.23. However, CYP1 enzymes are also capable of metabolism of endobiotics, and in the present study, the metabolism of retinoids and lipid endobiotics by human CYP1B1 and mouse Cyp1b1 orthologs was compared. Both hemoproteins oxidized retinol to retinal and retinal to retinoate, but did not oxidize retinoate. The CYP1B1 to Cyp1b1 CERs were 13 and 26 for the two steps, respectively; the Cyp1b1 K(m(app)) values for retinoids were 20-fold higher. Human family 1 cytochromes P450 had unique regional specificities for arachidonate oxidation: the major metabolites of CYP1A1, CYP1A2, and CYP1B1 were 75% terminal hydroxyeicosatetraenoic fatty acids (HETEs), 52% epoxyeicosatrienoic fatty acids (EETs), and 54% mid-chain HETEs, respectively. CYP1A1 and CYP1B1 K(m(app)) values for arachidonate were about 30 microM, whereas CYP1A2 K(m(app)) was 95 microM. The major metabolites of arachidonic acid by Cyp1b1 were EETs (50%) and midchain HETEs (37%). The mouse ortholog had a CER for metabolite production of 64 due to a K(m(app)) of 0.5 mM for arachidonate.