Rate of HIV-1 decline following antiretroviral therapy is related to viral load at baseline and drug regimen

OBJECTIVES AND DESIGN: The dynamics uf viral decline following the initiation of antiretroviral treatment were studied in 29 HIV-1-infected patients participating in a two-arm trial comparing immediate (group A: ritonavir, zidovudine and lamivudine) and delayed (group B: ritonavir supplemented by zidovudine and lamivudine on day 21) triple therapy. Parameters underlying viral dynamics were estimated using mathematical models tailored to these treatment protocols. RESULTS: The decline in plasma HIV-1 density between day 0 and 21 was steeper in group A (-2.27+/- 0.46 log10) than group B (-1.87+/-0.56 log10). In a subset of patients amenable to full mathematical analysis, a short-lived productively infected cell compartment (producing approximately 97% of total virions) decayed with a half-life of 1.0-2.5 days, whereas a long-lived infected cell compartment decayed with a half-life of 18.8-32.8 days. Estimates for the time for the elimination of virus from these two cell populations ranged from 474 to 802 days. The rate of loss of productively infected CD4+ T cells was positively correlated with baseline viral load in group A and in the combined dataset. CONCLUSIONS: These results suggest that HIV-infected cell populations may have a faster turnover in patients with higher viral loads due to higher infection rate parameters, higher rates of virus production, or lower virus clearance rates.     

Metal-thiolate clusters in the C-terminal domain of human neuronal growth inhibitory factor (GIF)

Neuronal growth inhibitory factor (GIF), a metallothionein-like protein (metallothionein-3), impairs the survival and neurite formation of cultured neurons. Native GIF contains 4 Cu(I) and three Zn(II) ions organized in homometallic metal-thiolate clusters. However, the cluster localization is not known. In this study, the metal-thiolate clusters formed with monovalent and divalent metal ions in the C-terminal domain of human GIF [GIF(32-68)] containing 11 cysteines were investigated. The cluster formation was followed by using electronic absorption, circular dichroism (CD), and magnetic circular dichroism (MCD) spectroscopy, and in the case of Cu(I) complexes also by luminescence spectroscopy at 77 K. Spectroscopic studies on the Cu(I)-GIF(32-68) complexes showed the successive formation of two air-sensitive Cu4S8-9- and Cu6S11-clusters. With Zn(II) and Cd(II) ions, a well-defined M4S11-cluster is formed in which each metal ion is tetrahedrally coordinated by cysteine thiolates. In the 113Cd NMR spectra of 113Cd4-GIF(32-68), recorded at 293 and 323 K, all four 113Cd resonances at 672.8, 620.9, 629.6, and 564.2 ppm were observed only at 323 K. Their detection at elevated temperature indicates a conformational flexibility of this domain. Evidence for the existence of a Cd6-GIF(32-68) complex, contaning two more weakly bound Cd(II) ions, was also obtained. The formation of this complex requires the transformation of some originally terminal thiolates of the Cd4S11-cluster to bridging thiolates, suggesting a more accessible cluster structure. Such properties of Cd4-GIF(32-68) have not been observed with the Cd4S11-cluster in the isolated alpha-domain (amino acids 31-61) of metallothioneins. The significance of Cu- and Zn-clusters for the structure of native GIF is discussed.     

Cloning and overexpression in Escherichia coli of the gene encoding citrate synthase from the hyperthermophilic Archaeon Sulfolobus solfataricus

A transurethral resection of the prostate is a good operation to relieve bladder outflow obstruction and has a low incidence of complications. However, recent work suggests that many men with symptoms may not require an operation, and it can probably be delayed in a majority for many years. This may be particularly important in old and frail patients. Many men with outflow obstruction have irritative symptoms such as urgency, frequency and nocturia; these could be treated with anticholinergics, provided they have normal flow rates and small or absent residual urine volumes. Pharmacological treatment to relieve outflow obstruction is disappointing. There may be some benefit from alpha-adrenoreceptor antagonists, but the place for 5 alpha-reductase inhibitors is still unsure. All drugs have side effects which are unacceptable in patients who are not bothered by their urinary symptoms and can wait for active treatment.