Postrenal transplant malignancies in a living-related donor program: 13-year experience--an update.
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Adult↗
Biomedical subjects
M Hussain
Publications and source records attributed to M Hussain.
Taxanes: an overview of the pharmacokinetics and pharmacodynamics.
Paclitaxel and docetaxel have emerged in the last two decades as effective antitumor agents in a variety of malignancies. Paclitaxel is a semisynthetic taxane isolated from bark of the Pacific yew tree. Docetaxel is a semisynthetic taxane derived from the needles of the European yew (Taxus baccata). These compounds bind to tubulin, leading to microtubule stabilization, mitotic arrest and, subsequently, cell death. Plasma clearance of paclitaxel exhibits nonlinear kinetics, which results in a disproportionate change in plasma concentration and area under the curve (AUC) with dose alterations. In contrast, docetaxel has a linear disposition over the dose ranges used clinically, so its concentration changes linearly with changes in the dosage. Premedicating with corticosteroids and histamine H1 and H2 receptor antagonists is advocated prior to paclitaxel administration; prior to docetaxel administration, premedication with corticosteroids is suggested. The taxanes are metabolized in the liver by the cytochrome P-450 enzymes and are eliminated in the bile. The known metabolites are either inactive or less potent than the parent compounds. The toxic effects associated with paclitaxel therapy are mainly neutropenia, peripheral neuropathy, and, rarely, cardiotoxicity. Docetaxel toxicity produces mainly myelosuppression and a cumulative dose fluid retention syndrome. Paclitaxel demonstrates sequence-dependent interactions with cisplatin, cyclophosphamide, and doxorubicin. Docetaxel has shown increased myelosuppression with preceding ifosfamide in a preliminary study. The future holds increasing indications for taxanes in newer combination regimens; consideration of their pharmacologic characteristics is an important aspect of designing and applying new taxane-based treatment regimens.
Antineoplastic Agents, Phytogenic↗
Mutations in the hepatitis B virus polymerase gene associated with antiviral treatment for hepatitis B.
Significant advances have been made, during the last 5 years, in the treatment of chronic hepatitis B. Several new antiviral agents: lamivudine, famciclovir, lobucavir and adefovir, have been shown to be safe and effective in inhibiting hepatitis B virus (HBV) replication. These compounds can be administered orally and are well tolerated. However, virus clearance is uncommon after short courses (<6 months) of therapy. Lamivudine and famciclovir have been evaluated in Phase III clinical trials in patients with chronic hepatitis B as well as in liver transplant recipients. Unfortunately, drug-resistant mutants involving the HBV polymerase gene, leading to breakthrough infection, have been reported in some patients who have received long courses (>/= 12 months) of treatment. The incidence, clinical outcome and biological significance of these mutants will be reviewed.
Amino Acid Sequence↗
Religious circumcision: a Muslim view.
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Age Factors↗
The pharmacokinetics of free insulin-like growth factor-I in healthy subjects.
In a randomized cross-over study in five healthy males we compared 75-min constant i.v. infusion of saline, low-dose recombinant human (rh) insulin-like growth factor-I (rhIGF-I; 1.5 microg/kg/h) and high-dose rhIGF-I (9.0 microg/kg/h). Serum samples were analysed for ultrafiltered free IGF-I (fIGF-I), total IGF-I (tIGF-I), tIGF-II and IGF-binding protein-1 (IGFBP-1) and -3. Free and total IGF-I were unchanged during saline infusion. Low-dose rhIGF-I caused a small increment in fIGF-I [+41%, from 0.64 +/- 0.19 (mean +/- SEM) to 0.90 +/- 0.25 microg/l;P< 0.05] and tIGF-I (+9%, from 220 +/- 31 to 239 +/- 33 microg/l;P< 0.05). High-dose rhIGF-I increased tIGF-I by 40% (from 227 +/- 36 to 329 +/- 31 microg/l;P< 0.05), and fIGF-I by 11.5 times (from 0.56 +/- 0.20 to 6.46 +/- 1.39 microg/l;P< 0.05). The pharmacokinetic profile of fIGF-I was calculated after high-dose IGF-I only. The disappearance of fIGF-I followed first order kinetics with an apparent half-life of 14.4 +/- 1.0 [11.2-17.1 (range)] min. The clearance was estimated to 52 +/- 20 (16-128) ml/min/kg and the volume of distribution to 1102 +/- 464 (388-2899) ml/kg. In the three experiments, there were no differences in IGFBP-1, and tIGF-II and IGFBP-3 remained unchanged. In conclusion, fIGF-I remained within the physiological range after low-dose rhIGF-I, whereas high-dose rhIGF-I resulted in supraphysiological concentrations. Since the half-life estimates for each subject were remarkably similar, this parameter most likely does not explain the observed variation in clearance and volume of distribution of fIGF-I. Instead, differences in the circulating and cellular IGF-I binding capacity may be of importance.
Adult↗
Prospective randomized comparison of tropisetron with and without dexamethasone against high-dose metoclopramide in prophylaxis of acute and delayed cisplatin-induced nausea and vomiting.
Several studies have confirmed the efficacy of high-dose metoclopramide and, more recently, serotonin antagonists, with and without dexamethasone, in the prophylaxis of cisplatin-induced nausea and vomiting. Most of these trials have been reported from Western countries. There is little or no information about the efficacy and tolerability of these agents in ethnic groups in other countries. Furthermore, many patients in the developing countries cannot afford serotonin antagonists. The result is a critical need to evaluate these agents and justify their increasingly common use. The authors performed a prospective randomized trial to compare the efficacy and tolerability of tropisetron with and without dexamethasone against high-dose metoclopramide cocktail in patients receiving a uniform dose of cisplatin (100 mg/m2). Metoclopramide 2 mg/kg was combined with clemastine, dexamethasone, and lorazepam. These drugs were initially repeated at short intervals and subsequently given in the oral form for the next 5 days. Tropisetron 5 mg was administered intravenously 15 minutes immediately before cisplatin therapy and followed up with oral therapy for 5 days. The third group received the same doses of tropisetron along with dexamethasone before cisplatin and twice daily thereafter. The authors randomized 301 episodes. The patient characteristics were well balanced between the three groups. Acute nausea and vomiting were completely prevented in almost two thirds of patients receiving metoclopramide and tropisetron plus dexamethasone. These results are significantly superior to those of tropisetron alone (p < 0.01). Similarly, delayed nausea and vomiting were significantly better controlled with metoclopramdie cocktail and tropisetron plus dexamethasone than with tropisetron alone. Side effects were generally mild; however, they were more frequent with metoclopramide. The authors conclude that metoclopramide-based combination antiemetic therapy continues to be a cheaper alternative to serotonin antagonists and equally effective. Metoclopramide-based therapy, however, is more labor intensive, and issues related to administrative errors, side effects, and compliance gain increasing importance. The identification of persons at a higher risk for metoclopramide-induced side effects may help minimize the unacceptable consequences of therapy.
Acute Disease↗
A lithium chloride-extracted, broad-spectrum-adhesive 42-kilodalton protein of Staphylococcus epidermidis is ornithine carbamoyltransferase.
To identify novel putative staphylococcal adhesins, lithium chloride extraction (an established method for selective surface molecule solubilization) was employed. N-terminal sequencing and functional assays identified a 42-kDa fibronectin-binding protein from Staphylococcus epidermidis as ornithine carbamoyltransferase (OCTase). However, OCTase was not recognizable extracellularly, and this fact together with the fact that LiCl induced DNA release and a decrease in viability suggests that LiCl extraction may not be the method of choice for selective surface molecule extraction from staphylococci.
Adhesins, Bacterial↗
Excitation-contraction coupling in rat ventricular myocytes after formamide-induced detubulation.
Formamide-induced osmotic shock has been used to detubulate isolated adult rat ventricular myocytes (i.e., disrupt the surface membrane-T tubule junction). Cell volume, calculated from cell length and width, rapidly decreased and increased upon application and removal of formamide, respectively. After treatment with formamide, membrane capacitance decreased by 26.4% (from 199.4 +/- 18.7 pF in control cells to 146.7 +/- 6.4 pF in formamide-treated cells; n = 13, P < 0.05). However, the amplitude of the L-type Ca(2+) current (I(Ca)) decreased by a greater extent (from 0.75 +/- 0.14 to 0.18 +/- 0.03 nA; n = 5, P < 0.05) so that the density of I(Ca) decreased by 74.5%. Simultaneous measurements of I(Ca) and Ca(2+) transients (monitored using fura 2) showed that both decreased rapidly upon removal of formamide. However, the Ca(2+) content of the sarcoplasmic reticulum showed little change. Cross-striations, visualized with the fluorescent dye di-8-aminonaphthylethenylpyridinium, were sparse or absent in cells that had been treated with formamide, suggesting that formamide can successfully detubulate cardiac cells and that I(Ca) is concentrated in the T tubules, which therefore play an important role in excitation-contraction coupling.
Animals↗
Eligibility and response guidelines for phase II clinical trials in androgen-independent prostate cancer: recommendations from the Prostate-Specific Antigen Working Group.
PURPOSE: Prostate-specific antigen (PSA) is a glycoprotein that is found almost exclusively in normal and neoplastic prostate cells. For patients with metastatic disease, changes in PSA will often antedate changes in bone scan. Furthermore, many but not all investigators have observed an association between a decline in PSA levels of 50% or greater and survival. Since the majority of phase II clinical trials for patients with androgen-independent prostate cancer (AIPC) have used PSA as a marker, we believed it was important for investigators to agree on definitions and values for a minimum set of parameters for eligibility and PSA declines and to develop a common approach to outcome analysis and reporting. We held a consensus conference with 26 leading investigators in the field of AIPC to define these parameters. RESULT: We defined four patient groups: (1) progressive measurable disease, (2) progressive bone metastasis, (3) stable metastases and a rising PSA, and (4) rising PSA and no other evidence of metastatic disease. The purpose of determining the number of patients whose PSA level drops in a phase II trial of AIPC is to guide the selection of agents for further testing and phase III trials. We propose that investigators report at a minimum a PSA decline of at least 50% and this must be confirmed by a second PSA value 4 or more weeks later. Patients may not demonstrate clinical or radiographic evidence of disease progression during this time period. Some investigators may want to report additional measures of PSA changes (ie, 75% decline, 90% decline). Response duration and the time to PSA progression may also be important clinical end point. CONCLUSION: Through this consensus conference, we believe we have developed practical guidelines for using PSA as a measurement of outcome. Furthermore, the use of common standards is important as we determine which agents should progress to randomized trials which will use survival as an end point.
Androgens↗
Prostate cancer: molecular biology of early progression to androgen independence.
To improve the therapy for prostate cancer, it will be necessary to address the problems of progression to androgen independence and the process of metastatic spread of tumour. The complexity of the latter condition is likely to mitigate against the immediate development of relevant therapeutic approaches. However, the basis of androgen independence appears to be a problem of simpler dimensions and more amenable to treatment with current therapeutic technology. Since early tumour progression can be detected by an incomplete prostate-specific antigen (PSA) response to androgen withdrawal therapy, a study of the molecular biology of PSA gene regulation may well provide insight into new methods for preventing or delaying this problem. Mounting evidence suggests that ligand-independent activation of the androgen receptor may be one underlying mechanism of androgen independence. In the absence of androgen, a compensatory increase in the activity of cAMP-dependent protein kinase (PKA) enhances the ability of the androgen receptor to bind to the response elements regulating PSA gene expression. The activation of the androgen receptor through up-regulation of the PKA signal transduction pathway involves the amino-terminus of the androgen receptor, the function of which may be altered either by modifications such as phosphorylation, or through interactions with co-regulators or other proteins. Of therapeutic interest is the fact that this effect can be counteracted experimentally by the anti-androgen, bicalutamide, and clinically by several other similar agents. We speculate that the inhibition of PKA-activated androgen receptor might also be accomplished by decoy molecules that can bind to the relevant activated site on the amino-terminus or competitively interact with proteins recruited by the PKA pathway that are responsible for activating the receptor in the absence of androgen. Such molecules might include small mimetic substances or agents that can gain access to the nucleus of the cell.
Cyclic AMP-Dependent Protein Kinases↗
Radiation therapy for a rising PSA level after radical prostatectomy.
With the advent of routine prostate-specific antigen (PSA) testing in asymptomatic young men, the number of patients undergoing radical prostatectomy is increasing. Effective therapy for the 30% to 40% of men who recur following radical prostatectomy is essential. Salvage radiation therapy for a rising serum PSA level is an effective therapy for controlling local recurrence. The impact of salvage radiotherapy on disease-free survival is promising, but the guidelines of therapy are not well established. The best candidates for salvage radiotherapy are those with a serum PSA level < 2 ng/mL with no palpable recurrence and complete urinary continence.
Humans↗
Cellular proliferation and prevalence of micrometastatic cells in the bone marrow of patients with clinically localized prostate cancer.
The presence of prostate cancer cells in the bone marrow (BM) of patients with clinically localized disease is associated with an increased chance of disease recurrence; however, not all patients develop recurrence. We therefore sought to determine the phenotype of individual micrometastatic cells as a potential method to better predict disease outcome. Immunostaining was performed on BM cells from 46 patients whose BM RNA fraction had been identified to contain prostate-specific antigen mRNA. The prevalence of micrometastatic cells among BM mononuclear cells was determined using an anticytokeratin antibody. Mib-1 antibody was used to determine the percentage of micrometastatic cells that were proliferating. Micrometastatic cells were found in 96% of patient samples, with a 30-fold variation in prevalence ranging from 0.1-3.26/10(5) BM cells. Prior androgen ablation was associated with a reduced prevalence of micrometastatic cells (P = 0.010). In 68% of patients, some micrometastatic cells were judged to be proliferating at proportions ranging from 1 of 11 (9%) to 4 of 4 (100%). Higher Gleason score of the primary tumor was associated with a higher proliferative proportion of micrometastatic cells (P = 0.038). We conclude that, in patients with clinically localized disease, there is wide variability in the prevalence of micrometastatic cells and the proportion which are proliferating. Long-term follow-up will determine whether the development of clinically obvious metastatic disease is related to higher prevalence of micrometastatic cells in the marrow or the proportion that are proliferating.
Bone Marrow↗
Hepatic overexpression of microsomal triglyceride transfer protein (MTP) results in increased in vivo secretion of VLDL triglycerides and apolipoprotein B.
The microsomal triglyceride transfer protein (MTP) is essential for the hepatic secretion of apolipoprotein (apo) B-containing lipoproteins. Previous studies have indicated that inhibition of MTP results in decreased apoB plasma levels and decreased hepatic triglyceride secretion. However, the metabolic effects of overexpression of MTP have not been investigated. We constructed a recombinant adenovirus expressing MTP (AdhMTP) and used it to assess the effects of hepatic overexpression of MTP in mice. Injection of AdhMTP into C57BL/6 mice resulted in a 3-fold increase in hepatic microsomal triglyceride transfer activity compared to mice injected with Adnull. On day 4 after virus injection, AdhMTP-injected mice had significantly elevated plasma TG levels as compared to control virus (Adnull)-injected mice. Hepatic TG secretion rates were significantly greater in AdhMTP-injected mice (184 +/- 12 mg/kg/h) compared with Adnull-injected mice (65 +/- 9 mg/kg/h, P < 0.001). In addition, hepatic very low density lipoprotein (VLDL) apoB secretion in the AdhMTP-injected group was 74% higher than in the control virus group. Hepatic secretion of apoB-48 and apoB-100 contributed equally to this increase. These results provide the first data that hepatic overexpression of MTP results in increased secretion of VLDL-triglycerides as well as VLDL-apoB in vivo. These results suggest that MTP is rate-limiting for VLDL apoB secretion in wild-type mice under basal chow-fed conditions.
Animals↗
Docetaxel (Taxotere) and estramustine versus mitoxantrone and prednisone for hormone-refractory prostate cancer: scientific basis and design of Southwest Oncology Group Study 9916.
Hormone-refractory prostate cancer is the terminal step in the natural history of prostate cancer. To date, no chemotherapeutic agents have been shown to impact clinical outcome at this stage. Recently, the Food and Drug Administration approved the combination of mitoxantrone and prednisone based solely on its superior palliative effects as compared to steroids alone in 2 randomized trials. Progress in biologically driven drug development has led to the identification of several estramustine-based regimens that, although based on single institution experience, appear to have at least a comparable but very promising level of activity in hormone-refractory prostate cancer patients. One such combination, estramustine plus docetaxel (Taxotere; Rhône-Poulenc Rorer, Collegeville, PA), is particularly attractive because of its convenient schedule and side effect profile. To objectively assess the therapeutic benefit of this combination, the Southwest Oncology Group is initiating a randomized phase III trial comparing estramustine and docetaxel with the standard arm of mitoxantrone and prednisone using time to progression and survival as the primary end points. Secondary end points will include toxicity profiles, assessments of quality of life parameters, and magnitude of decline of prostate-specific antigen levels between the two treatment arms.
Adenocarcinoma↗
Investigations of a rinderpest outbreak in buffaloes in Pakistan.
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Animals↗
Cattle plague in Shangri-La: observations on a severe outbreak of rinderpest in northern Pakistan 1994-1995.
Between April 1994 and November 1995 the most severe epidemic of rinderpest reported in the world for over a decade affected domestic livestock in the Northern Areas of Pakistan. As many as 40,000 cattle and yaks died, more by some estimates, and mortality rates may have exceeded 80 per cent in these species in several villages. This report describes some of the clinicopathological and epidemiological features peculiar to the outbreak, including laboratory-confirmed rinderpest in a goat, and the difficulties encountered before the disease was eradicated. It also describes the human costs and emphasises the need to accelerate the global eradication of this most eradicable disease.
Agriculture↗
MR demonstration of a giant cavernous carotid aneurysm with occlusion of the contralateral intracranial carotid artery: an unusual complication of cavernous sinus thrombosis.
We present an unusual combination of vascular complications of cavernous sinus thrombosis in a 7-year-old girl. MRI and MR angiography showed occlusion of the intracranial portion of the left internal carotid artery and a contralateral giant cavernous carotid aneurysm. This combination of vascular findings may influence the management in such cases.
Aneurysm, Infected↗
Lifetime health risk assessment from exposure of recreational users to polycyclic aromatic hydrocarbons.
In order to assess the lifetime risk of skin cancer for recreational users from dermal exposure to polycyclic aromatic hydrocarbons (PAHs), sediment samples were collected from beach sites along the St. Marys River near Sault Ste. Marie, Ontario, and in Hamilton Harbor and Toronto Harbor, Ontario, and analyzed for PAHs. Dermal exposure and lifetime skin cancer risk were estimated as follows: Concentrations of 11 PAHs with sufficient or limited evidence of carcinogenicity or mutagenicity were converted to benzo(a)pyrene (BaP) equivalents using toxic equivalency factors (TEFs). Lifetime dermal exposure values were derived based on the BaP equivalents in the silt + clay fraction taken as representative of suspended sediment particulates to which recreational users would be exposed. The lifetime health risk of skin cancer associated with such exposures was above the negligible risk level of 1.0 x 10(-6) at offshore Rytac, Lake George Channel, and Bell Point beaches in the St. Marys River; at Pier 4 Park in Hamilton Harbor; and at Humber Bay, Sunnyside Beach, Cherry Beach, and Water Rats Sailing Club in Toronto Harbor. Risk was negligible inshore at the Rytac and Bell Point beaches and at Squirrel Island and Ojibway Trailer Park along St. Marys River, at Lax Beach in Hamilton Harbor; and at Centre Island in Toronto Harbor. Strategies to reduce risk were developed with these communities; a key recommendation was to take a bath or shower within 24 h after a swim because virtually all the PAHs on the skin would be removed.
Animals↗