Mapping the Anopheles gambiae odorant binding protein 1 (AgamOBP1) using modeling techniques, site directed mutagenesis, circular dichroism and ligand binding assays.

The major malaria vector in Sub-Saharan Africa is the Anopheles gambiae mosquito. This species is a key target of malaria control measures. Mosquitoes find humans primarily through olfaction, yet the molecular mechanisms associated with host-seeking behavior remain largely unknown. To further understand the functionality of A. gambiae odorant binding protein 1 (AgamOBP1), we combined in silico protein structure modeling and site-directed mutagenesis to generate 16 AgamOBP1 protein analogues containing single point mutations of interest. Circular dichroism (CD) and ligand-binding assays provided data necessary to probe the effects of the point mutations on ligand binding and the overall structure of AgamOBP1. Far-UV CD spectra of mutated AgamOBP1 variants displayed both substantial decreases to ordered α-helix structure (up to22%) and increases to disordered α-helix structure(up to 15%) with only minimal changes in random coil (unordered) structure. In mutations Y54A, Y122A and W114Q, aromatic side chain removal from the binding site significantly reduced N-phenyl-1-naphthylamine binding. Several non-aromatic mutations (L15T, L19T, L58T, L58Y, M84Q, M84K, H111A, Y122A and L124T) elicited changes to protein conformation with subsequent effects on ligand binding. This study provides empirical evidence for the in silico predicted functions of specific amino acids in AgamOBP1 folding and ligand binding characteristics.

Responsiveness of muscle protein synthesis to growth hormone administration in HIV-infected individuals declines with severity of disease.

This study was undertaken to determine if human recombinant growth hormone (hrGH, 6 mg/d for 2 wk) would stimulate muscle protein synthesis in AIDS wasting. Healthy controls were compared with patients who were HIV+, had AIDS without weight loss, and had AIDS with > 10% weight loss. Before hrGH, rates of skeletal muscle protein synthesis, measured with l-[2H5]phenylalanine, were the same in controls and in all stages of disease. Rates of myofibrillar protein degradation, however, assessed from urinary excretion of 3-methyl histidine, were higher in AIDS and AIDS wasting than in HIV+ or healthy individuals. The group with weight loss had significantly higher TNFalpha levels but not higher HIV viral loads. Muscle function, as determined by isokinetic knee extension and shoulder flexion, was significantly higher in controls than all infected individuals. After GH, rates of protein synthesis were stimulated 27% in controls, with a smaller increase (11%) in HIV+, and a significant depression (42%) in AIDS with weight loss, despite fourfold elevation in insulin-like growth factor-I in all groups. There was a significant correlation of hrGH-induced changes in muscle protein synthesis with severity of disease (P = 0.002). The results indicate increased basal muscle protein degradation and decreased responsiveness of muscle protein synthesis to GH in the later stages of disease.

Factors affecting the ozone sensitivity of temperate European grasslands: an overview.

This overview of experimentally induced effects of ozone aims to identify physiological and ecological principles, which can be used to classify the sensitivity to ozone of temperate grassland communities in Europe. The analysis of data from experiments with single plants, binary mixtures and multi-species communities illustrates the difficulties to relate individual responses to communities, and thus to identify grassland communities most at risk. Although there is increasing evidence that communities can be separated into broad classes of ozone sensitivity, the database from experiments under realistic conditions with representative systems is too small to draw firm conclusions. But it appears that risk assessments, based on results from individuals or immature mixtures exposed in chambers, are only applicable to intensively managed, productive grasslands, and that the risk of ozone damage for most of perennial grasslands with lower productivity tends to be less than previously expected.

Characterization of a membrane-associated glycoprotein (gp 43) on human hepatocellular carcinoma by a monoclonal antibody.

A monoclonal antibody, Hepama-1, produced by immunizing mice with cells of a human hepatocellular carcinoma cell line, has been used to identify and characterize a previously unreported antigen present on the surface of human hepatocellular carcinoma cells. The antigen occurred on the membranes of human hepatoma cell lines and tumor biopsies but was not detectable in tumors of other origin or normal tissues. Binding was determined by enzyme-linked immunoabsorbent assay and immunofluorescence on cell lines and by immunoperoxidase staining of tissue sections. In immunofluorescence studies, Hepama-1 antibodies stained five out of six human hepatoma cell lines, showed only slight binding to breast tumor cell lines, but failed to stain colon tumor or normal cell lines. The antihepatoma antibody exhibited positive immunoperoxidase staining of human liver tumor sections but did not stain tumors of other origin. Hepama-1 bound specifically to a membrane glycoprotein with an approximate molecular weight of 43,000. Western blot and solid phase enzyme-linked immunoabsorbent assay analysis showed that the 43-kD antigen occurred on five of six human hepatoma cell lines and was expressed by every human hepatocellular carcinoma biopsy tested. This cell surface molecule represents a potentially useful target for immunotherapy and localization of human hepatocellular carcinomas.

Isolation and characterization of a monoclonal antibody specific for epithelial cells.

Monoclonal antibodies were generated to antigens on human foreskin keratinocytes to identify epithelial-specific molecules. Spleen cells from BALB/c mice, immunized with membrane preparations from primary explants of foreskin epithelial cells, were fused with the NS-1 mouse myeloma line. Hybridoma supernatants were screened for the desired immunological reactivity using enzyme-linked immunosorbant binding assays. Hybridomas secreting antibodies reacting with epithelial cells, but not fibroblasts or lymphocytes, were cloned by limiting dilution, and two stable clones producing immunoglobulin M K antibodies were selected for study. Evaluation of fixed paraffin-embedded human tissue by an indirect immunoperoxidase technique revealed that the antibodies bound most strongly to normal stratified squamous and transitional epithelium, and squamous and transitional cell carcinomas. Antibodies from the cloned hybridomas also reacted with primary cell cultures of foreskin keratinocytes, pulmonary epithelium, fetal liver, and amnion cells, but not with primary cultures of nonepithelial cells. Further testing by enzyme-linked immunosorbent assays revealed that the antibodies reacted with some long-term cell lines derived from epithelial tumors. Nonepithelial cell lines were not stained by the antibodies. Indirect immunofluorescent studies indicated that staining was confined to the cell surface. These antibodies may prove useful in studies of differentiation markers of human epithelial cells.

Enhanced expression of ganglioside GD3 in human and rat hepatocellular carcinoma cells and NIH 3T3 cells transfected with human tumor DNAs.

The gangliosides of human hepatoma biopsies, human hepatoma cell lines, and diethylnitrosamine-induced rat hepatomas were examined. These malignant tissues all expressed increased content of disialolactosylceramide (GD3) with respect to their normal counterparts. During the induction of rat hepatoma by diethylnitrosamine, an increase in GD3 levels appeared as early as 12 wk after initiation of diethylnitrosamine, concurrent with the appearance of precancerous hepatocytes. GD3 levels gradually increased to a peak of 4 times that of normal rat liver at 20 wk. CMP-NeuAc:GM3 sialyltransferase, the enzyme that synthesizes GD3 by transfer of sialic acid to GM3, also had tumor-associated elevation during the course of diethylnitrosamine-induction of rat hepatomas. To investigate the relationship of oncogene transformation and changes in ganglioside biosynthesis, NIH 3T3 cells transfected DNAs from human hepatoma or nasopharyngeal carcinoma were studied. The transfectants each expressed the same ganglioside composition, including a detectable level of GD3, as well as enhanced activity of CMP-NeuAc:GM3 sialyltransferase. A correlation between the tumor DNA transfection and the augmentation of GD3 in malignant cells is discussed. Because of the early appearance of GD3 in hepatoma and its possible relationship to oncogene activation, GD3 may be a potentially useful early tumor marker.

Total Thyroidectomy for Amiodarone-induced Thyrotoxicosis in the Hyperthyroid State.

Amiodarone is a potent antiarrhythmic agent, indicated for the treatment of refractory arrhythmias, which may lead to thyrotoxicosis. In these patients, thyroidectomy is a valid therapeutic option. Antithyroid therapy in the immediate preoperative setting and the subsequently accepted minimal delay until thyroidectomy have not been clearly defined yet. The aim of the present study was to show, that total thyroidectomy under general anaesthesia in patients with amiodarone-induced thyrotoxicosis (AIT) is safe without necessarily obtaining an euthyroid state preoperatively.We conducted a retrospective cohort study of prospectively gathered data on 11 patients undergoing total thyroidectomy under general anaesthesia between January 2008 and December 2013 for AIT at our University Hospital.All patients were preoperatively treated with carbimazole, steroids and ß-receptor antagonists. Additionally, 3 patients received potassium perchlorate and in one patient carbimazole was changed to propylthiouracil. Plasmapheresis was performed in 3 patients. Only one patient was euthyroid at the time of operation. There were no significant intra- and postoperative complications, especially no signs of thyroid storm. One patient could postoperatively be removed from the cardiac transplant waiting list due to improved cardiac function.Improvements in the interdisciplinary surgical management for AIT between cardiologists, endocrinologists, anaesthetists and endocrine surgeons provide the basis of safe total thyroidectomy under general anaesthesia in hyperthyroid state. Early surgery without long delay for medical antithyroid treatment (with its potential negative side effects) is recommended.

Analysis of ras oncogene products by two-dimensional gel electrophoresis: evidence for protein families with distinctive molecular forms.

Protein products of the ras family of oncogenes were immunoprecipitated by an anti-p21 monoclonal antibody, separated by two-dimensional gel electrophoresis and subsequently detected by western immunoblot analysis using the same anti-p21 monoclonal antibody as a probe. Using this method, a 21 kDa oncogene protein (p21) was detected and characterized in cell lines containing Harvey (Ha), Kirsten (Ki), neuroblastoma (N), or cellular (proto) ras genes. The ras gene products from all cell types occurred with multiple forms differing in size, charge or in both parameters. Transforming ras oncogene proteins occurred in easily identifiable groups that were different from each other in molecular weight and charge, were distinctive for each ras gene type and were different from cellular ras equivalents. Similar, but not identical, family groups occurred in different cell types containing the same oncogene. The reproducible occurrence of unpredicted p21 forms suggests that previously unreported post-translational processing steps may be associated with the synthesis of certain oncogene products. This immunoprecipitation/two-dimensional gel/western blot technique is a simple method for the identification and characterization of p21 gene products.

Effects of elevated ozone on leaf delta13C and leaf conductance of plant species grown in semi-natural grassland with or without irrigation.

Stable carbon isotope ratios (delta(13)C) and leaf conductance (g(s)) were measured (2002, 2003) in Holcus lanatus L., Plantago lanceolata L. Ranunculus friesianus (Jord.), and Trifolium pratense L. at two levels of ozone (O(3)) with or without irrigation. In non-irrigated control plots, R. friesianus showed the least negative delta(13)C, and the smallest response to the treatments. Irrigation caused more negative delta(13)C, especially in H. lanatus. Irrespective of irrigation, O(3) increased delta(13)C in relationship to a decrease in g(s) in P. lanceolata and T. pratense. The strongest effect of O(3) on delta(13)C occurred in the absence of irrigation, suggesting that under field conditions lack of moisture in the top soil does not always lead to protection from O(3) uptake. It is concluded that in species such as T. pratense plants can maintain stomatal O(3) uptake during dry periods when roots can reach deeper soil layers where water is not limiting.

Seasonal trends in reduced leaf gas exchange and ozone-induced foliar injury in three ozone sensitive woody plant species.

Seasonal trends in leaf gas exchange and ozone-induced visible foliar injury were investigated for three ozone sensitive woody plant species. Seedlings of Populus nigra L., Viburnum lantana L., and Fraxinus excelsior L. were grown in charcoal-filtered chambers, non-filtered chambers and open plots. Injury assessments and leaf gas exchange measurements were conducted from June to October during 2002. All species developed typical ozone-induced foliar injury. For plants exposed to non-filtered air as compared to the charcoal-filtered air, mean net photosynthesis was reduced by 25%, 21%, and 18% and mean stomatal conductance was reduced by 25%, 16%, and 8% for P. nigra, V. lantana, and F. excelsior, respectively. The timing and severity of the reductions in leaf gas exchange were species specific and corresponded to the onset of visible foliar injury.

Disseminated sporotrichosis in patients with AIDS: case report and review of the literature.

Sporotrichosis is the disease caused by the dimorphic fungus Sporothrix schenkii. Disseminated sporotrichosis is an uncommon infection which usually occurs in alcoholics or patients receiving immunosuppressive medication. We report a case of a patient with AIDS who had disseminated sporotrichosis which was progressive and fatal despite antifungal therapy. Four previously reported cases of disseminated sporotrichosis in patients with AIDS are reviewed. Disseminated sporotrichosis occurs in patients with HIV-1 infection and severe CD4 lymphocyte depletion. It usually presents with diffuse cutaneous lesions and is associated with polyarticular arthritis. Response to treatment is variable and chronic suppressive therapy is probably needed to prevent relapse.

Ventricular tachycardia in two patients with AIDS receiving ganciclovir (DHPG).

We report two cases of patients who developed ventricular tachycardia while receiving intravenous infusions of ganciclovir [9-(1,3-dihydroxy-2-propoxy)methylguanine, DHPG]. Worsening cytomegalovirus infection prompted renewal of ganciclovir therapy under close cardiac monitoring in one of these patients, and ventricular tachycardia recurred. The close temporal relationship between administration of the drug and onset of the arrhythmias in conjunction with the absence of other factors known to predispose to arrhythmias suggest that ganciclovir may have played a role in the development of arrhythmias in these patients. The clinical courses of the patients are discussed, as are autopsy results.

Albumin synthesis and bone collagen formation in human immunodeficiency virus-positive subjects: differential effects of growth hormone administration.

Loss of lean tissue often accompanies human immunodeficiency virus (HIV) infection. Exogenous human recombinant GH (hrGH) has been shown to be beneficial in reversing this wasting. However, catabolic effects of hrGH on muscle protein metabolism have also been reported. Therefore, the responsiveness of other GH-sensitive tissues, including bone formation and albumin synthesis, has been examined. Anabolic activity in bone, from serum levels of carboxy-terminal propeptide of type I collagen, was stimulated by 2 weeks of hrGH in controls (56 +/- 15%, P = 0.002), patients with asymptomatic HIV (24 +/- 10%, not significant), patients with AIDS (47 +/- 7%, P < 0.001), and patients with AIDS and > 10% weight loss (21 +/- 12%, P = 0.02). Albumin synthesis, determined from the incorporation of L-[2H5]phenylalanine, was increased in response to hrGH in controls (23 +/- 7%, P < 0.05), HIV+ subjects (39 +/- 16%, P < 0.05), and patients with AIDS (25 +/- 7%, P < 0.01). Patients with AIDS and weight loss, however, did not increase albumin synthesis (-0.6 +/- 12%) in response to hrGH. The results indicate variable anabolic responses to hrGH. Bone collagen synthesis remained sensitive to hrGH, whereas, the anabolic action of hrGH on the synthesis of albumin diminished with severity of disease. However unlike muscle protein synthesis, albumin synthesis was not depressed below basal levels by hrGH.

In situ detection of PCR-amplified HIV-1 nucleic acids in lymph nodes and peripheral blood in patients with asymptomatic HIV-1 infection and advanced-stage AIDS.

This study determined the in situ detection rate of polymerase chain reaction (PCR)-amplified human immunodeficiency virus type 1 (HIV-1) DNA and RNA in lymph nodes and peripheral blood CD4+ cells in six patients with asymptomatic HIV-1 infection and from six people who died of advanced AIDS. The lymph nodes of patients with asymptomatic infection showed expanded germinal centers where, on average, 20% of the CD21+ dendritic cells contained HIV-1 DNA. From 5 to 80% of the CD4+ cells in these lymph nodes contained HIV-1 DNA, as compared with 1-11% of the CD4+ peripheral blood mononuclear cells. The infection in most cells was latent in the asymptomatic group. In contrast, the lymph nodes of patients with advanced AIDS showed marked depletion of both dendritic and CD4+ cells. The majority of the remaining CD4+ cells in the lymph nodes and blood showed PCR-amplified viral DNA and cDNA sequences suggesting the presence of genomic and multiple spliced transcripts. It is concluded that asymptomatic HIV-1 infection is associated with a wide range of latent to active viral-positive CD4+ lymphocytes and dendritic cells in the lymph nodes. Progression to AIDS is characterized by active viral replication in many of the remaining CD4+ cells in the lymph nodes and blood.

Pilot study comparing the salivary cationic protein concentrations in healthy adults and AIDS patients: correlation with antifungal activity.

This investigation compared the salivary cationic protein concentrations of 12 healthy adult controls with those of 12 hospitalized patients with AIDS. Salivas were quantified by capillary electrophoresis using purified cationic protein standards. In parotid saliva, histidine-rich polypeptides (HRPs) 1-6, histatin 6, and lysozyme concentrations were determined. In addition to these eight cationic proteins, submandibular-sublingual saliva was also quantified for histatin 2 and the histatin 2 degradation product. When comparisons were made on the basis of individual proteins, the HRP-histatin concentrations in the AIDS patients showed either statistically significant decreases or a decreasing trend compared with healthy adult controls. When HRP-histatin concentrations were summed for each patient, there were statistically significant differences between the healthy adult controls and the individuals with AIDS in both parotid and submandibular-sublingual salivas. Closer examination revealed that some individuals with AIDS had HRP-histatin concentrations that fell within the normal range of the healthy adult controls. For these individuals, lower than expected salivary antifungal values were obtained. Either decreasing histidine-rich protein concentrations and/or an inability of these proteins in saliva to interact with Candida albicans may contribute to the defective salivary antifungal activity seen in AIDS patients.

Determination of salivary anticandidal activities in healthy adults and patients with AIDS: a pilot study.

This investigation compared the salivary anticandidal activities of 12 healthy adults with 12 hospitalized patients with AIDS. Stimulated parotid, submandibular-sublingual, and whole salivas were collected during a period of 10 min, immediately acidified, boiled, and then centrifuged to isolate salivary supernatants. Supernatants were then tested for antifungal activity against Candida albicans in blastospore viability inhibition and germ tube formation assays. A unit of blastospore or germ tube antifungal activity was established as that activity yielding 90% or greater inhibition during a defined time period in each salivary assay. Each of the patients with AIDS were found to be defective in one or more of their salivary antifungal activities, and in comparison with healthy adults the differences in antifungal units per milliliter of saliva and total antifungal units were statistically significant for each saliva and each antifungal assay. Defective salivary antifungal activity may contribute to the oral candidiasis seen in patients with AIDS.

Increased central body fat deposition precedes a significant rise in resting blood pressure in male offspring of essential hypertensive parents: a 5 year follow-up study.

OBJECTIVES: As long as offspring of essential hypertensive parents (OHyp) are lean, their blood pressure usually remains within normal limits. The mechanism(s) transforming this 'genetically dysregulated normotension' into hypertension are unclear. We hypothesized that OHyp are not only genetically prone to develop hypertension, but may also have a particular propensity to accumulate central body fat. DESIGN: A 5-year follow-up cohort study. SETTING: University Hospital in Switzerland. PARTICIPANTS: Seventeen young (25 +/- 1 years, mean +/- SD), lean healthy normotensive male OHyp and 17 age- and sex-matched offspring of normotensive parents (ONorm) paired for baseline blood pressure with the OHyp. MAIN OUTCOME MEASURES: Resting and exercise blood pressure, body weight, body mass index (BMI) and waist-to-hip ratio were assessed at baseline and after 5 years. RESULTS: At baseline, body weight, BMI, waist-to-hip ratio and blood pressure did not differ significantly between OHyp and ONorm. At follow-up, body weight was increased in both groups (from 73.9 +/- 6.0 to 77.7 +/- 8.1 kg in OHyp, P = 0.008, and from 71.5 +/- 6.9 to 73.5 +/- 6.6 kg in ONorm, P = 0.03). BMI followed a similar pattern. In contrast, waist-to-hip ratio increased in OHyp (from 0.84 +/- 0.03 to 0.87 +/- 0.03, P = 0.012), but not in ONorm (from 0.84 +/- 0.03 to 0.84 +/- 0.04, P = 0.79) and was therefore higher in OHyp at follow-up (P = 0.011, OHyp versus ONorm). Peak systolic blood pressure during dynamic exercise also rose at 5 years in the OHyp (from 182 +/- 10 to 214 +/- 17 mmHg, P = 0.0001) while resting systolic blood pressure only tended to do so (from 121 +/- 7 to 128 +/- 12 mmHg, P = 0.07). In ONorm, resting and peak dynamic exercise systolic blood pressure remained unchanged (119 +/- 11 versus 121 +/- 9 mmHg, baseline versus follow-up, P = 0.40, and 186 +/- 12 versus 196 +/- 22 mmHg, P = 0.10, respectively). Thus, systolic peak exercise blood pressure was significantly (P = 0.014) elevated at follow-up in OHyp compared to ONorm, while resting systolic blood pressure only tended (P = 0.06) to do so. CONCLUSIONS: Initially lean normotensive OHyp have a disparate long-term course of central body fat as compared to ONorm. Thus, OHyp are not only genetically prone to develop hypertension, but they also have a particular propensity to accumulate central body fat, even before a distinct rise in resting blood pressure occurs. The exaggerated blood pressure response to exercise observed at follow-up in the OHyp represents another marker that confers them a greater risk of developing future hypertension.

The anticarcinogenic and tumor growth inhibitory activities of lymphotoxin are associated with altered membrane glycoprotein synthesis.

Membrane glycoprotein synthesis was studied in non-tumorigenic and tumor cells treated with the lymphokine hormone, lymphotoxin, to define the biochemical mechanisms by which lymphotoxin prevents carcinogenesis and inhibits growth of tumor cells. Syrian hamster lymphotoxin increased the synthesis of high molecular weight (50,000-250,000) membrane glycoproteins in non-tumorigenic secondary passage NIH/N Syrian hamster embryo fibroblasts and caused a decrease in the synthesis of high molecular weight glycoproteins in benzo[a]pyrene-induced hamster tumor cells. Increased glycoprotein synthesis varied directly with lymphotoxin concentration and duration of treatment and occurred contemporaneously with lymphotoxin-initiated prevention of carcinogen-induced morphologic transformation. These lymphotoxin-stimulated fluctuations in membrane glycoprotein synthesis are evidence of specific biochemical target cell changes associated with the anticarcinogenic and tumor-inhibitory actions of this immunologic hormone.

The response of spring wheat (Triticum aestivum L.) to ozone at higher elevations. III. Responses of leaf and canopy gas exchange, and chlorophyll fluorescence to ozone flux.

Spring wheat (Triticum aestivum L., cv. Albis) was grown in open-top chambers and exposed to four different levels of ozone (O3 ) from the three-leaf stage until maturity. The aim was to examine changes in leaf and canopy gas exchange, and in chlorophyll fluorescence, in response to O3 flux. Measurements were carried out periodically between full expansion and complete senescence of flag leaves. Fluxes to the canopy of CO2 (CERc .) (corrected for soilborne CO2 ), water vapour (Ec ) and O3 were determined by using open-top chambers as differential systems. Water use efficiency (WUEc .) was calculated from CERc , and Ec . Leaf CO2 (CERn ) and H2 O (En ) exchange rates, stomatal conductance (g,(H2 O)), and WUEn , were analyzed with a portable gas exchange analyzer. Effects of O3 flux on structural components of photosynthesis were examined by determining variable fluorescence (defined by the Fv /Fo ratio) in leaves after 60 minutes of dark-adaptation or during the night. The decline in CERc and CERn associated with senescence was accelerated by O3 . Average CERn between flag leaf unfolding and late milk stage declined linearly with increasing O3 flux. The corresponding decline in average CERc was less pronounced. The quantitative effect of O3 flux on CERc corresponded well with the effect on grain yield. In young leaves, gs (H2 O) was reduced in response to O3 but WUEn was unaffected. With progressing leaf age, WUEn declined. Thus, in the young leaves, O3 affected the stomata directly and, consequently, limitation of photosynthesis was primarily due to reduced CO2 diffusion. In contrast, in senescent leaves, the effect of O3 was mainly due to reduced carboxylation. Compared with WUEn WUEc responded differently to increasing O3 flux. During O2 fluxes at above-ambient levels, WUEC tended to increase rather than to decrease. It is suggested that under O3 stress, factors controlling WUE at the canopy level differ from those operating at the level of single flag leaves. The decline in Fv /Fo measured after anthesis was stimulated by O2 , but no effect of O3 was detected when Fv /Fo was measured during the night. This leads to the conclusion that the effect of O3 on photosynthetic structures is reversible and the reduction in photosynthesis in response to O3 flux is due to metabolic changes rather than to direct damage to structural components.

Changing conditions and treatments in a dynamic cohort of ambulatory HIV patients: the HIV outpatient study (HOPS).

PURPOSE: Most HIV-infected persons are now treated as ambulatory patients. Obtaining continually updated data about these patients' changing conditions, therapies, and reimbursement is essential to health care provision and planning. The systematic tracking of patient medical and laboratory information in an ongoing commercial data collection program (The Health Research Network) allows clinicians to better understand health outcomes, practice patterns, and epidemiologic trends for their patients. METHODS: To evaluate trends in conditions and therapies of ambulatory HIV-infected patients, we analyzed such data electronically and prospectively collected in the HIV Outpatient Study (HOPS) from 1992 through 1996 from 1876 patients seen in 11,755 clinic visits to ten HIV clinical practices. RESULTS: Patients were as likely to be diagnosed with Mycobacterium avium complex ([MAC] 5.4 cases per 100 person-years) or wasting syndrome (7.8 cases per 100 person-years), as Pneumocystis carinii pneumonia ([PCP]; 7.6 cases per 100 person-years) or Kaposi sarcoma ([KS]; 6.9 cases per 100 person-years). A nested analysis showed that HIV-infected cigarette smokers were at substantially greater risk of pneumonia (relative hazard [RH] = 2.3), bronchitis (RH = 1.7) and hairy leukoplakia (RH = 1.9) than nonsmokers. By 1996, 35 (56%) of 62 patients with PCP, 9 (30%) of 30 patients with other pneumonias, 28 (90%) of 31 patients with KS, 35 (73%) of 48 patients with MAC, and 24 (63%) of 38 patients with cytomegalovirus retinitis were treated without hospitalization. CONCLUSIONS: The HOPS provides continually updated information on the changing characteristics, conditions, and therapy of ambulatory HIV-infected patients.