Selective employment of chemokine receptors as human immunodeficiency virus type 1 coreceptors determined by individual amino acids within the envelope V3 loop

The chemokine receptor CCR5 acts as an essential cofactor for cell entry by macrophage-tropic human immunodeficiency virus type 1 (HIV-1) strains, whereas CXCR4 acts as an essential cofactor for T-cell-line-adapted strains. We demonstrated that the specific amino acids in the V3 loop of the HIV-1 envelope protein that determine cellular tropism also regulate chemokine coreceptor preference for cell entry by the virus. Further, a strong correlation was found between HIV-1 strains classified as syncytium inducing in standard assays and those using CXCR4 as a coreceptor. These data support the hypothesis that progressive adaptation to additional coreceptors is a key molecular basis for HIV-1 phenotypic evolution in vivo.     

Proceedings of the Joint US/EU Workshop: urinary biomarkers to detect significant effects of environmental and occupational exposure to nephrotoxins

Tear cytokines and growth factors are likely to modulate the wound healing process following corneal epithelial injury. Hepatocyte growth factor (HGF) is a paracrine mediator of epithelial proliferation, motility, and differentiation that is produced by keratocytes and the lacrimal gland. Tear samples were collected preoperatively and one, two, and seven days postoperatively in eyes undergoing excimer laser surface ablation [photorefractive keratoplasty (PRK) or phototherapeutic keratoplasty (PTK)]. Tear HGF concentration was measured with a sensitive ELISA assay. Tear HGF production was calculated using the tear flow rate in the collection capillary and HGF concentration. Although the instantaneous concentration of HGF in tears decreased significantly in the days following PRK, a large increase in tear flow resulted in a marked increase in HGF bioavailability. The heparin-binding characteristics of HGF would result in increased binding to glycosaminoglycans and other heparin-like matrix components and, therefore, increased growth factor availability to the cognate recptor. This is the first report documenting changes in tear film HGF production. HGF may have an important function in maintenance and wound healing of the ocular surface epithelium since HGF is present in the normal tear film and the HGF secretion rate increases markedly in parallel with aqueous tear production following corneal surgical injury.     

Presence of enamel on the incisors of the llama (Lama glama) and alpaca (Lama pacos)

Cytoplasmic aggregation is an early resistance-associated event that is observed in potato tissues either after penetration of an incompatible race of Phytophthora infestans, the potato late blight fungus, or after treatment with hyphal wall components (HWC) prepared from P. infestans. In potato cells in suspension culture, the number of cells with cytoplasmic aggregation increased upon treatment with HWC, but such an increase was suppressed by treatment with cytochalasin D prior to treatment with HWC. This result suggested that cytoplasmic aggregation in cultured potato cells might be connected with the association of actin filaments. To identify the molecular basis of cytoplasmic aggregation, we purified actin and actin-related proteins by affinity chromatography on a column of immobilized DNase I from cultured potato cells and isolated proteins of 43 kDa, 32 kDa and 22 kDa. Analysis of the amino-terminal amino acid sequences indicated that the 43 kDa, 32 kDa and 22 kDa proteins were potato actin, basic chitinase and osmotin-like protein, respectively. This conclusion was supported by the results of Western blotting analysis of the 43 kDa and 32 kDa proteins with antibodies against actin and basic chitinase. Binding analysis with actin coupled to actin-specific antibodies and biotinylated actin suggested that the 32 kDa and 22 kDa proteins had actin-binding activity. In addition, examination of biomolecular interactions using an optical biosensor confirmed the binding of chitinase to actin. These results imply the possibility that basic chitinase and osmotin-like protein might be involved in cytoplasmic aggregation, hereby participating. In the potato cell's defense against attack by pathogen.     

Assessment of cocaine use with quantitative urinalysis and estimation of new uses

Qualitative urinalysis methods of monitoring cocaine use may over-detect frequency of use, possibly decreasing the ability of clinical trials to detect effective treatments. Quantitative urinalysis and newly developed criteria for identifying new cocaine use were evaluated as alternative measures of cocaine use. Urine specimens collected in a cocaine dosing study in non-treatment-seeking subjects (n = 5) and a cocaine treatment trial (n = 37) were analyzed for the cocaine metabolite, benzoylecgonine, with qualitative and quantitative methods. Pharmacokinetic criteria ('New Use' rules) were applied to quantitative data to identify occasions of new cocaine use. Results were compared to known cocaine administrations in the laboratory study and to self-reported drug use and qualitative urinalysis for subjects in the clinical trial. New Use criteria correctly identified cocaine administrations in the cocaine dosing study in all but a small number of specimens. In the clinical trial, quantitative urinalysis and estimated New Uses provided more information about patterns and frequency of use than qualitative urinalysis in the different treatment conditions in the clinical trial. Interpretation of quantitative urinalysis with New Use rules appears to be a useful method for monitoring treatment outcome and may be more accurate than traditional qualitative urinalysis in estimating frequency of cocaine use.     

Identification of the blood-borne somatotroph-differentiating factor during chicken embryonic development

Somatotrophs become a significant population by day 16 of chicken embryonic development. We have previously demonstrated that an earlier induction of GH cell differentiation is possible with the addition of day 16 embryonic serum to cultures of day 12 pituitary cells, an age when somatotrophs are rare. The present study was designed to identify the blood-borne signal(s) responsible for the serum activity, using reverse hemolytic plaque assays to identify individual GH-secreting cells. The activity was found to be a heat-stable, ether-soluble compound(s) that is bound or inhibited by a trypsin-sensitive protein. The extent of GH cell differentiation was greater (P < 0.05; n = 3) in response to the ether phases of heated day 16 (14.1 +/- 0.4% of all cells) and day 12 sera (9.3 +/- 0.4%) than with untreated serum from days 16 and 12 (6.1 +/- 0.4% and 0.82 +/- 0.4%, respectively). Furthermore, ether-extracted day 16 serum was more effective than ether-extracted day 12 serum, which was also different from basal (0.85 +/- 0.4%; P < 0.05). Based on this biochemical profile, the abilities of various steroids to stimulate differentiation were tested. Three steroids were found to stimulate somatotroph differentiation in vitro: 17beta-estradiol, corticosterone, and progesterone. However, the estradiol receptor antagonist, tamoxifen, while abolishing the effect of estradiol, had no effect on the induction of differentiation by day 16 serum. In contrast, RU486, a specific glucocorticoid receptor antagonist in chickens, blocked the stimulatory effects of corticosterone, progesterone, and day 16 serum on somatotroph differentiation. We next tested whether the active compound in day 16 embryonic serum was corticosterone, the predominant glucocorticoid in chickens. Incubation of day 16 serum with corticosterone antiserum, but not control antiserum, suppressed day 16 serum-induced GH cell differentiation. Therefore, we conclude that corticosterone is the blood-borne signal capable of stimulating somatotroph differentiation in vitro. The present findings together with previous reports indicate that somatotroph differentiation during embryonic development may result from an increase in circulating glucocorticoid concentrations.     

Molecular cloning of CYP1A from the estuarine fish Fundulus heteroclitus and phylogenetic analysis of CYP1 genes: update with new sequences

Since we published a phylogenetic analysis of the CYP1A subfamily in 1995, several additional full-length sequences have been reported, including three members of an entirely new subfamily, CYP1B. Two avian sequences were recently published, so that CYP1A sequence data are now available from three of the five major vertebrate lineages. The two new branches that have been added to the CYP1 family tree significantly add to our understanding of P450 evolution. The inclusion of the CYP1Bs to the phylogenetic analysis allows us to root inferred trees. Addition of the avian CYP1As indicates that the CYP1A1/CYP1A2 duplication present in the mammalian lineage may have occurred after the divergence of birds and mammals. The number of fish species from which full-length coding regions of CYP1A genes have been sequenced has increased from four (trout, plaice, toadfish, and scup) to nine. These include CYP1A sequences from tomcod, butterflyfish, sea bream, sea bass, and the full-length sequence of CYP1A from the killifish Fundulus heteroclitus that is reported here. Phylogenetic analyses incorporating the new fish CYP1A sequences support our original conclusion that the fish CYP1As are monophyletic and indicate that the genes are evolving at very different rates in different species.     

Incremental iron overload during reperfusion progressively augments oxidative injury

OBJECTIVE: To determine if a relationship exists between the extent of iron-catalyzed injury and the degree of tissue iron overload during reperfusion. METHODS: To selectively increase tissue iron only during early reperfusion, isolated, buffer perfused rabbit hearts were exposed to 20 microM Fe(2+)-100 microM ADP during the last 3 minutes of ischemia and the initial 4 minutes of reperfusion. Control groups were exposed to ADP and iron-ADP regimens that did not increase intracellular iron. All the hearts received 30 minutes of normothermic global ischemia and 30 minutes of reperfusion. Heart function was monitored continuously throughout each experiment. Tissue iron and biochemical markers were analyzed at the end of experiments. RESULTS: Hemodynamic recovery was decreased and tissue lipid peroxide levels were increased in the 20 microM Fe(2+)-100 microM ADP group compared to controls. The recoveries of developed pressure and positive/negative dP/dT at 30 minutes of reperfusion were negatively correlated with tissue iron levels, while cytosol and membrane lipid peroxide levels correlated positively with the iron levels during reperfusion. CONCLUSION: The extent of oxidative injury during reperfusion was directly related to the tissue iron burden present during reperfusion. Increased lipid peroxidation was the principal chemical marker of iron-catalyzed injury.     

The end of the continuum. Bereavement care for the adult

A method has been developed for the simultaneous analysis of the isomeric N-acetyl-S-(dichlorophenyl)cysteines (also known as dichlorophenylmercapturic acids, DCPMAs) in urine. This procedure allows the determination of 2,3- and 3,4-DCPMAs at the concentrations expected in the urine samples of employees occupationally exposed to 1,2-dichlorobenzene (1,2-DCB). The results of a 1,2-DCB exposure study under standardized conditions show a first-order kinetic for the excretion of DCPMAs, as well as acceptable linear correlations between the urinary concentrations of DCPMAs and the amount of inhaled 1,2-DCB. It therefore seems it would be possible to derive a biological tolerance value for 1,2-DCB based on isomeric DCPMAs as analytical parameters.     

Ventricular perforation associated with central venous introducer-dilator systems

BACKGROUND: An erythrocyte sedimentation rate (ESR) of at least 40 mm/h is considered an important requisite for the diagnosis of polymyalgia rheumatica (PMR). However, the relative frequency and clinical features of PMR in patients without a significantly increased ESR are unclear. METHODS: We performed a retrospective study of patients diagnosed as having PMR at the rheumatology divisions of 3 teaching hospitals. The diagnosis of PMR was established, regardless of the ESR, in 201 consecutive patients fulfilling the following criteria: (1) age 50 years or older, (2) severe proximal pain for more than 1 month in at least 2 of 3 areas: neck, shoulder, and/or pelvic girdles, and (3) rapid resolution of the syndrome while taking low-dose prednisone. Patients with giant cell arteritis were previously excluded from the study. The frequency and clinical features of patients with PMR and an ESR lower than 40 mm/h were analyzed. A comparative study between these patients and those with high ESRs was performed. RESULTS: An ESR lower than 40 mm/h was found in 41 patients (20.4%). These patients were younger (P = .02), were more frequently men (P = .006), and experienced a lower frequency of fever (P = .003) and weight loss (P = .07). Furthermore, these patients were characterized by an absence of anemia (P = .002) and a lower frequency of abnormal protein electrophoresis results (P < .001). Otherwise, their clinical syndrome, response to therapy, and frequency of relapses were similar to those of patients with classic PMR. In the entire population of 201 patients, the ESR was related to the length of treatment, number of areas involved, presence of fever, weight loss, and laboratory test result abnormalities, but it was unrelated to the duration of the illness prior to diagnosis. CONCLUSIONS: It is not uncommon to find a patient with PMR with an ESR lower than 40 mm/h. This syndrome is more frequent in men and it is clinically less severe than the classic form of PMR. Its recognition will allow these patients to benefit from an effective treatment with low-dose corticosteroids.