Exposure of the grass shrimp, Palaemonetes pugio, to antimicrobial compounds affects associated Vibrio bacterial density and development of antibiotic resistance.

Antimicrobial compounds are widespread, emerging contaminants in the aquatic environment and may threaten ecosystem and human health. This study characterized effects of antimicrobial compounds common to human and veterinary medicine, aquaculture, and consumer personal care products [erythromycin (ERY), sulfamethoxazole (SMX), oxytetracycline (OTC), and triclosan (TCS)] in the grass shrimp Palaemonetes pugio. The effects of antimicrobial treatments on grass shrimp mortality and lipid peroxidation activity were measured. The effects of antimicrobial treatments on the bacterial community of the shrimp were then assessed by measuring Vibrio density and testing bacterial isolates for antibiotic resistance. TCS (0.33 mg/L) increased shrimp mortality by 37% and increased lipid peroxidation activity by 63%. A mixture of 0.33 mg/L TCS and 60 mg/L SMX caused a 47% increase in shrimp mortality and an 88% increase in lipid peroxidation activity. Exposure to SMX (30 mg/L or 60 mg/L) alone and to a mixture of SMX/ERY/OTC did not significantly affect shrimp survival or lipid peroxidation activity. Shrimp exposure to 0.33 mg/L TCS increased Vibrio density 350% as compared to the control whereas SMX, the SMX/TCS mixture, and the mixture of SMX/ERY/OTC decreased Vibrio density 78-94%. Increased Vibrio antibiotic resistance was observed for all shrimp antimicrobial treatments except for the mixture of SMX/ERY/OTC. Approximately 87% of grass shrimp Vibrio isolates displayed resistance to TCS in the control treatment suggesting a high level of TCS resistance in environmental Vibrio populations. The presence of TCS in coastal waters may preferentially increase the resistance and abundance of pathogenic bacteria. These results indicate the need for further study into the potential interactions between antimicrobials, aquatic organisms, and associated bacterial communities.

Decay-accelerating factor is present on paroxysmal nocturnal hemoglobinuria erythroid progenitors and lost during erythropoiesis in vitro.

A glycoprotein that regulates the deposition of C3b on the erythrocyte surface, called decay-accelerating factor or DAF, is absent from the red blood cells (RBC) of patients with paroxysmal nocturnal hemoglobinuria (PNH), explaining in part their abnormal sensitivity to complement. We used a specific antiserum to DAF, flow microfluorometry, and clonogenic assays for erythroid progenitor cells to study PNH erythropoiesis in vitro. By fluorescence-activated cell sorter analysis, all RBC from normal individuals are DAF+. In contrast, the RBC of six patients with PNH showed discrete populations of DAF- cells (10-44%; x +/- SEM = 31 +/- 6%). The DAF- RBC population was partly eliminated by prior acidified serum lysis. To determine whether erythropoietic progenitors expressed DAF, bone marrow cells were sorted by flow microfluorometry and the separated DAF+ and DAF- populations then cultured in vitro. In two normal individuals, but also in six patients with PNH, erythroid colonies formed only from cells in the DAF+ fraction. However, a variable proportion of the normoblast progeny of these DAF+ progenitor cells from patients with PNH was DAF-. Individual bursts removed from cultures of PNH bone marrow showed two discrete populations by fluorescence; the majority of normoblasts were DAF-, only 3 of 27 individual bursts had greater than 50% DAF+ cells, and in three patients, DAF- normoblasts averaged 79%. In contrast, the progeny of individual bursts from normal individuals comprised a unimodal DAF+ population. In each PNH patient, one normal burst (greater than 80% DAF+ normoblasts) was detected, possibly reflecting a normal residual population of erythroid progenitors. By the criterion of DAF expression, there was no evidence of separate populations of normal and PNH type progenitor cells. The phenotypically normal erythroid progenitors of PNH bone marrow acquire the PNH characteristics during differentiation in vitro.

Age- and gender-specific modulation of serum osteopontin and interferon-alpha by osteopontin genotype in systemic lupus erythematosus.

Osteopontin (OPN) is a multifunctional cytokine involved in long bone remodeling and immune system signaling. Additionally, OPN is critical for interferon-alpha (IFN-alpha) production in murine plasmacytoid dendritic cells. We have previously shown that IFN-alpha is a heritable risk factor for systemic lupus erythematosus (SLE). Genetic variants of OPN have been associated with SLE susceptibility, and one study suggests that this association is particular to men. In this study, the 3' UTR SLE-risk variant of OPN (rs9138C) was associated with higher serum OPN and IFN-alpha in men (P=0.0062 and P=0.0087, respectively). In women, the association between rs9138 C and higher serum OPN and IFN-alpha was restricted to younger subjects, and risk allele carriers showed a strong age-related genetic effect of rs9138 genotype on both serum OPN and IFN-alpha (P<0.0001). In African-American subjects, the 5' region single nucleotide polymorphisms, rs11730582 and rs28357094, were associated with anti-RNP antibodies (odds ratio (OR)=2.9, P=0.0038 and OR=3.9, P=0.021, respectively). Thus, we demonstrate two distinct genetic influences of OPN on serum protein traits in SLE patients, which correspond to previously reported SLE-risk variants. This study provides a biologic relevance for OPN variants at the protein level, and suggests an influence of this gene on the IFN-alpha pathway in SLE.

Thomy-headed worm infection in north american prehistoric man.

Examination of ova and parasites from coprolites of probable human origin revealed eggs of the phylum Acanthocephala. Specimens were gathered from Danger Cave in Utah, an area heavily populatd with definitive rodent hosts for the Acanthocephala species Moniliformis clarki. It is postulated that prehistoric man developed Acanthocephala infection by ingesting the arthropod intermediate host, or that he was a victim of false parasitism by ingesting the whole rodent.

Argon-40: excess in submarine pillow basalts from kilauea volcano, hawaii.

Submarine pillow basalts from Kilauea Volcano contain excess radiogenic argon-40 and give anomalously high potassium-argon ages. Glassy rims of pillows show a systematic increase in radiogenic argon-40 with depth, and a pillow from a depth of 2590 meters shows a decrease in radiogenic argon40 inward from the pillow rim. The data indicate that the amount of excess radiogenic argon-40 is a direct function of both hydrostatic pressure and rate of cooling, and that many submarine basalts are not suitable for potassium-argon dating.

Enterobius vermicularis: 10,000-year-old human infection.

Eggs of Enterobius vermicularis (human pinworm) were found in hum coprolites from Hopug and Danger Caves, western Utah. The Caves were inhabitated by man from 10,000 B.C. to A.D. 1400. The oldest coprolite containing dated at 7837 B.C. This represents the earliest known association between man abd this exclusively human parasite.

Deposit from a giant wave on the island of lanai, hawaii.

Limestone-bearing gravel, the newly named Hulopoe Gravel, blankets the coastal slopes on Lanai. The deposit, which reaches a maximum altitude of 326 meters, formerly was believed to have been deposited along several different ancient marine strandlines, but dated submerged coral reefs and tide-gauge measurements indicate that the southeastern Hawaiian Islands sink so fast that former worldwide high stands of the sea now lie beneath local sea level. Evidence indicates that the Hulopoe Gravel and similar deposits on nearby islands were deposited during the Pleistocene by a giant wave generated by a submarine landslide on a sea scarp south of Lanai.

Gang exposure and pregnancy incidence among female adolescents in San Francisco: evidence for the need to integrate reproductive health with violence prevention efforts.

Among a cohort of 237 sexually active females aged 14-19 years recruited from community venues in a predominantly Latino neighborhood in San Francisco, California, the authors examined the relation between gang exposure and pregnancy incidence over 2 years of follow-up between 2001 and 2004. Using discrete-time survival analysis, they investigated whether gang membership by individuals and partners was associated with pregnancy incidence and determined whether partnership characteristics, contraceptive behaviors, and pregnancy intentions mediated the relation between gang membership and pregnancy. Pregnancy incidence was determined by urine-based testing and self-report. Latinas represented 77% of participants, with one in five born outside the United States. One quarter (27.4%) became pregnant over follow-up. Participants' gang membership had no significant effect on pregnancy incidence (hazard ratio = 1.25, 95% confidence interval: 0.54, 3.45); however, having partners who were in gangs was associated with pregnancy (hazard ratio = 1.90, 95% confidence interval: 1.09, 3.32). The male partner's perceived pregnancy intentions and having a partner in detention each mediated the effect of partner's gang membership on pregnancy risk. Increased pregnancy incidence among young women with gang-involved partners highlights the importance of integrating reproductive health prevention into programs for gang-involved youth. In addition, high pregnancy rates indicate a heightened risk for sexually transmitted infections.

Characterization of a virus that causes transient aplastic crisis.

Transient aplastic crisis in children with congenital hemolytic anemias has been linked epidemiologically to infection with a serum parvovirus-like virus (SPLV). The virus is found in the blood in the early stages of the crisis, and serum containing SPLV inhibits erythroid colony formation in vitro. After sedimentation of virus-containing sera through a sucrose density gradient, colony inhibitory activity is present in the particulate fraction and separate from serum immunoglobulins. No inhibitory activity can be recovered from convalescent-phase sera after similar fractionation procedures. Inhibition of erythroid colony formation in vitro is not a feature of sera from other viral infections. The pattern of resistance of SPLV activity to chemicals and enzymes is compatible with it being a parvovirus. By using replating techniques, a target of SPLV has been identified as a late erythroid progenitor cell. Neither SPLV antigen nor anti-SPLV IgM was present in the sera of patients with other forms of bone marrow failure.

5-Azacytidine acts directly on both erythroid precursors and progenitors to increase production of fetal hemoglobin.

The effect of 5-azacytidine on erythroid precursors and progenitors was studied in nine patients with sickle cell anemia or severe thalassemia. Each patient received the drug intravenously for 5 or 7 d. 5-Azacytidine caused a four- to sixfold increase in gamma-messenger RNA concentration in bone marrow cells of eight of the nine patients and decreased the methylation frequency of a specific cytosine residue in the gamma-globin gene promoter in all nine patients. Within 2 d of the start of drug treatment there was a rise in the percentage of reticulocytes containing fetal hemoglobin (HbF; F-reticulocytes) without a significant change in the total number of reticulocytes, which suggested that there was a direct action of 5-azacytidine on erythroid precursors. Late erythroid progenitors (CFU-E), present in bone marrow after 2 d of drug administration, formed colonies containing an increased amount of HbF as compared with control colonies. Moreover, the number of CFU-E derived colonies was not decreased at these early times, which suggested that there was a direct action of 5-azacytidine on erythroid progenitors in the absence of cytotoxicity. Exposure of normal bone marrow cells in tissue culture to 5-azacytidine for 24 h reproduced both of these effects as judged during subsequent colony formation. The combined direct effects of 5-azacytidine on both the erythroid precursor and progenitor compartments resulted in an increase in HbF synthesis that was sustained for 2-3 wk. Toxicity to bone marrow as reflected by cytoreduction was evident after treatment in some patients but was not accompanied by an increase in HbF production. A correlation was found between the effects of 5-azacytidine on bone marrow, as assessed by in vitro measurements, and the hematological response of the individual patients to drug treatment.

A new lectin in red kidney beans called PvFRIL stimulates proliferation of NIH 3T3 cells expressing the Flt3 receptor.

A new legume lectin has been identified by its ability to specifically stimulate proliferation of NIH 3T3 fibroblasts expressing the Flt3 tyrosine kinase receptor. The lectin was isolated from conditioned medium harvested from human peripheral blood mononuclear cells activated to secrete cytokines by a crude red kidney bean extract containing phytohemagglutinin (PHA). Untransfected 3T3 cells and 3T3 cells transfected with the related Fms tyrosine kinase receptor do not respond to this lectin, which we called PvFRIL (Phaseolus vulgaris Flt3 receptor-interacting lectin). When tested on cord blood mononuclear cells enriched for Flt3-expressing progenitors, purified PvFRIL fractions maintained a small population of cells that continued to express CD34 after 2 weeks in suspension cultures containing IL3. These cultures did not show the effects of IL3's strong induction of proliferation and differentiation (high cell number and exhausted medium); instead, low cell number at the end of the culture period resulted in persistence of cells in the context of cell death. These observations led to the hypothesis that PvFRIL acts in a dominant manner to preserve progenitor viability and prevent proliferation and differentiation.

Gastrointestinal chronopharmacology: physiology, pharmacology and therapeutic implications.

This chapter discusses the influence of ultradian and circadian rhythms of gastrointestinal motor and secretory function on the action of orally administered drugs. Most drugs exhibit more rapid absorption in the morning compared to the evening due, in part, the circadian alterations in gastric emptying. Gastric acid secretion and gastrointestinal toxicity to oral drugs also display circadian rhythmicity. These observations provide a rationale for use or avoidance of drugs based on time-of-day dosing considerations. The chronopharmacological behavior of a drug may thus play an important role in the effectiveness of any oral medication treatment schedule.

The role of weak protein-protein interactions in multivalent lectin-carbohydrate binding: crystal structure of cross-linked FRIL.

Binding of multivalent glycoconjugates by lectins often leads to the formation of cross-linked complexes. Type I cross-links, which are one-dimensional, are formed by a divalent lectin and a divalent glycoconjugate. Type II cross-links, which are two or three-dimensional, occur when a lectin or glycoconjugate has a valence greater than two. Type II complexes are a source of additional specificity, since homogeneous type II complexes are formed in the presence of mixtures of lectins and glycoconjugates. This additional specificity is thought to become important when a lectin interacts with clusters of glycoconjugates, e.g. as is present on the cell surface. The cryst1al structure of the Glc/Man binding legume lectin FRIL in complex with a trisaccharide provides a molecular snapshot of how weak protein-protein interactions, which are not observed in solution, can become important when a cross-linked complex is formed. In solution, FRIL is a divalent dimer, but in the crystal FRIL forms a tetramer, which allows for the formation of an intricate type II cross-linked complex with the divalent trisaccharide. The dependence on weak protein-protein interactions can ensure that a specific type II cross-linked complex and its associated specificity can occur only under stringent conditions, which explains why lectins are often found forming higher-order oligomers.

Moderate weight loss and sulfonylurea treatment of non-insulin-dependent diabetes mellitus. Combined effects.

Hypocaloric liquid formula diets were given for one month to 20 moderately obese patients with non-insulin-dependent diabetes mellitus divided into two equal groups; group 1 was treated with weight loss alone; group 2 received glipizide in addition to the hypocaloric diet. Mean weight loss was similar in the two groups (6.5 +/- 0.6 v 6.4 +/- 0.5 kg) and was associated with a statistically significant fall in mean fasting plasma glucose values from 293 +/- 15 to 232 +/- 24 mg/dL (group 1) and from 281 +/- 15 to 152 +/- 7 mg/dL (group 2). This was associated with 13% (group 1) and 36% (group 2) decrements in total postprandial glucose response. Neither fasting nor postprandial insulin levels changed significantly with weight loss, but estimates of insulin-stimulated glucose disposal demonstrated a 15% (group 1) and 42% (group 2) improvement. Finally, fasting plasma cholesterol and triglyceride concentrations fell significantly in both groups.

Characterization of the hematopoietic defect in paroxysmal nocturnal hemoglobinuria.

We studied the relationship between paroxysmal nocturnal hemoglobinuria (PNH) and bone marrow failure using in vitro hematopoietic colony culture assays. Most of 17 patients with PNH showed decreased colony formation, by erythroid burst-forming cells (BFU-E) and granulocyte-macrophage colony-forming cells (CFU-C) in methylcellulose, disproportionate to their degree of bone marrow biopsy cellularity. Only a minority of the hematopoietic progenitors were sensitive to complement-mediated lysis in vitro. In contrast, normoblasts from maturing erythroid bursts removed from culture and exposed to acidified serum were sensitive to complement-mediated lysis. The size of bursts and the sensitivity of their progeny correlated strongly, suggesting that the PNH defect was acquired in culture as a function of the generational age of erythroid precursor cells. In addition, BFU-E of PNH patients were very sensitive to 3H-thymidine suicide, in comparison with normal individuals and patients with other hemolytic anemias, indicating that a large proportion of primitive erythroid progenitors in PNH bone marrow were in cell cycle. All of these results imply that acquisition of the PNH defect during erythropoiesis may lead to intramedullary destruction of developing erythroid cells. The increased demand that results on the progenitor pool may lead to stem cell depletion and bone marrow failure.

The plant lectin FRIL supports prolonged in vitro maintenance of quiescent human cord blood CD34(+)CD38(-/low)/SCID repopulating stem cells.

Ex vivo maintenance of human stem cells is crucial for many clinical applications. Current culture methods rely on optimized combinations of cytokines. Although these conditions provide some level of stem cell support, they primarily induce proliferation and differentiation, resulting in reduced repopulation capacity. The recently identified legume lectin FRIL has been shown to preserve human cord blood progenitors up to a month in suspension culture without medium changes. To test whether FRIL also preserves human SCID repopulating stem cells (SRC), we cultured human CD34(+) cord blood cells in medium containing FRIL, with or without subsequent exposure to cytokines, and tested their repopulating potential. We report that FRIL maintains SRC between 6 and 13 days in culture. Incubation of CD34(+) cells with FRIL results in significantly lower numbers of cycling cells compared with cytokine-stimulated cells. CD34(+) cells first cultured with FRIL for 6 days and subsequently exposed to cytokines for an additional 4 days generated significantly more mononuclear and progenitor cells and higher levels of engraftment in NOD/SCID mice compared with CD34(+) cells cultured with FRIL alone. Similar results were obtained with CD34(+)CD38(-/low) cells, including expansion of SRC that were cultured in FRIL followed by cytokine stimulation. Moreover, CD34(+) cells precultured with FRIL successfully engrafted primary and more importantly secondary recipients with lymphoid and myeloid cells, providing further support that FRIL maintains SRC for prolonged periods.FRIL's ability to preserve quiescent primitive cells in a reversible manner may significantly expand the time and range of ex vivo manipulations of human stem cells for clinical applications.

Pharmacodynamics of intravenous ranitidine after bolus and continuous infusion in patients with healed duodenal ulcers.

Fifteen adult men who had histories of duodenal ulcer disease were studied for 24 hours during treatment with varying intravenous doses of ranitidine (50 mg every 8 hours, 100 mg every 12 hours, 6.25 mg/hr continuous infusion, and 10 mg/hr continuous infusion) and placebo. Gastric pH was monitored under fasting conditions by means of an indwelling pH sensitive electrode. The continuous infusion regimens provided the most constant level of acid suppression. A "breakthrough" decrease in gastric pH began at approximately 6 PM at the 6.25 mg/hr dose level. The drop in pH at the 10 mg/hr dose level was less impressive. Ranitidine, 100 mg every 12 hours, resulted in better acid suppression than the regimen of 50 mg every 8 hours. A gastric pH greater than or equal to 4 was achieved 35 to 50 minutes after the start of administration for all regimens. The median effective concentration (EC50) of ranitidine was approximately 45 ng/ml. Continuous infusion regimens, with a dosage adjustment for the time of day, may be the optimal dosage regimen for patients requiring continuous protection from gastric damage by hydrochloric acid. Bolus loading doses are not required to speed the onset of effect in the clinical setting.

Confirmation of short solid-food lag phase by continuous monitoring of gastric emptying.

Reports on the existence of a lag phase before solid-food gastric emptying are conflicting. We studied solid-phase gastric emptying in ten normal-weight male subjects using two opposed cameras and continuous monitoring. Each ingested a 300-g meal containing 99mTc-labeled liver pate. Identical computer-interfaced cameras continuously monitored gastric activity from anterior and posterior projections. Lag phase was determined by three techniques: (1) inspection of the emptying curve; (2) time to a 2% decrease in stomach activity; and (3) the time of visual appearance of duodenal activity. A short lag phase time was found using all methods, averaging 8.6 min. We concluded that a short solid meal lag phase exists that can be missed with conventional radionuclide gastric emptying methods not employing continuous measurements.

Gastric emptying measurements: delayed and complex emptying patterns without appropriate correction.

Anteriorly acquired and geometric mean corrected gastric emptying curves of solids and liquid isotopic-labeled meals were compared in 37 subjects given 61 meals of three different sizes. Anterior data alone consistently and significantly underestimated solid-phase gastric emptying rates with all meal sizes when compared to geometric mean acquired data. However, with liquids there were only slight differences between anterior and anterior and posterior geometric mean corrected emptying-rates. The difference probably reflects greater attenuation of the 140 kev photon of 99mTc compared to the 247 keV photon of 111In. With anterior data alone, an apparent early delay in emptying of solids was present with all meal sizes and the resultant emptying curves were nonlinear in shape. Geometric mean correction resulted in the linearization of the solid-phase emptying curves and essentially eliminated the apparent delay in emptying or lag phase noted with the anterior data alone. Based on our results, geometric mean correction techniques are necessary for accurate assessment of radioisotopic-labeled solid meals.

Gastric emptying studies in the morbidly obese before and after gastroplasty.

Dual isotope gastric emptying studies were performed on 16 morbidly obese patients before and after gastroplasty to determine the effect of this surgery on the rate of emptying. The solid and liquid phases of gastric emptying were compared with a normal control group. In the 900-g and 50-g meals there was a significant difference in the mean half emptying time between solid and liquid phases of emptying (p less than 0.05). Pre-operatively, the 900-g meal half emptying times of both solids and liquids and the 50-g liquid phase meal did not differ significantly between obese patients and the control group. However, in the solid phase of the 50-g meal obese patients differed significantly from a control group (p = 0.007). Three months after gastroplasty, gastric emptying of 50-g meals from the total stomach was not significantly changed from the pre-operative 50-g meal values in ten of 12 patients (p less than 0.05) and no change in total stomach emptying times were seen at 12 mo compared to the 3-mo study (p less than 0.05). Emptying of the pouch alone for both solids and liquids was significantly faster than the pre-operative and postoperative total stomach studies. Gastric emptying in the obese is normal with large meals, but is delayed in small meals. In most patients, gastroplasty does not result in slower emptying of meals.