Diverse styles of submarine venting on the ultraslow spreading Mid-Cayman Rise.

Thirty years after the first discovery of high-temperature submarine venting, the vast majority of the global mid-ocean ridge remains unexplored for hydrothermal activity. Of particular interest are the world's ultraslow spreading ridges that were the last to be demonstrated to host high-temperature venting but may host systems particularly relevant to prebiotic chemistry and the origins of life. Here we report evidence for previously unknown, diverse, and very deep hydrothermal vents along the approximately 110 km long, ultraslow spreading Mid-Cayman Rise (MCR). Our data indicate that the MCR hosts at least three discrete hydrothermal sites, each representing a different type of water-rock interaction, including both mafic and ultramafic systems and, at approximately 5,000 m, the deepest known hydrothermal vent. Although submarine hydrothermal circulation, in which seawater percolates through and reacts with host lithologies, occurs on all mid-ocean ridges, the diversity of vent types identified here and their relative geographic isolation make the MCR unique in the oceans. These new sites offer prospects for an expanded range of vent-fluid compositions, varieties of abiotic organic chemical synthesis and extremophile microorganisms, and unparalleled faunal biodiversity--all in close proximity.

Keratinocyte growth factor ameliorates cyclophosphamide-induced ulcerative hemorrhagic cystitis.

To determine whether keratinocyte growth factor (KGF), an epithelial and urothelial growth factor, ameliorates cyclophosphamide (CP)-induced cystitis in rats, KGF (5 mg/kg) was injected in rats as a single i.v. injection 24 h prior to i.p. injection of CP (200 mg/kg). Bladders were evaluated histologically 48 h after CP injection, and KGF pretreatment was found to almost completely prevent CP-induced ulcerative hemorrhagic cystitis. Urinary KGF levels were measured by ELISA, and KGF was found to be undetectable in control urine, but it was found to appear in the urine of KGF-treated rats at 8 h, with a peak concentration of approximately 10 ng/ml. Bilateral nephrectomy did not diminish the proliferative effect of KGF on urothelium, suggesting that the contribution of urinary KGF to urothelial proliferation is insignificant. In conclusion, systemic administration of KGF is protective against CP-induced cystitis. Although KGF appears in the urine, urinary KGF is not necessary for the proliferative action of KGF on urothelium.

Enzyme immunoassays for the detection of bacterial antigens utilizing biotin-labeled antibody and peroxidase biotin--avidin complex.

This report describes the use of biotin-labeled antibodies in sensitive enzyme immunoassay systems for the measurement of bacterial antigens. Biotinylated immunoglobulins could be reproducibly formulated using N-hydroxysuccinimide biotin ester to link biotin to the immunoglobulin. Binding of the biotinylated antibody to solid-phase antigen was efficiently measured by reaction with a complex consisting of biotinylated antibody and unlabeled avidin. This immunoassay system was at least as sensitive as ones which utilized enzyme-labeled or fluorescein-labeled antibodies for the detection of antigens from Streptococcus pneumoniae and Haemophilus influenzae type b. In the case of Streptococcus pneumoniae the assay system could detect antigen in the supernatants from broth cultures containing as few as 10(3) organisms/ml. Assay systems utilizing biotinylated antibody and avidin-biotin complex can provide for sensitive, specific assays for the measurement of microbial antigens.

Intracerebroventricular administration of leptin markedly enhances insulin sensitivity and systemic glucose utilization in conscious rats.

This study examines the acute, subacute (overnight), and chronic (7-day) effects of intracerebroventricular (i.c.v.) administration of r-metMuLeptin on insulin sensitivity and systemic glucose turnover in conscious unrestrained rats (body weight, 250 to 300 g). Under postabsorptive conditions, acute i.c.v. leptin ([AL] 10 microg bolus) did not affect tracer (3-(3)H-glucose)-determined glucose production (GP) and utilization (GU) rates during the 2-hour hyperinsulinemic (2 mU x kg(-1) x min(-1)) euglycemic clamp. Chronic i.c.v. leptin ([CL] 10 microg/d for 7 days) administered by osmotic pumps markedly reduced the daily food consumption (P < .05), body weight (P < .05), and postabsorptive basal plasma glucose level (P < .01). During the glucose clamp, GP was markedly suppressed (55%) with CL (P < .001 v vehicle and pair-fed control groups). The insulin-induced increment in GU was significantly greater with CL (23.3 +/- 1.8 mg(-1) x kg(-1) x min(-1)) than with vehicle (16.9 +/- 0.2) and pair-feeding (17.1 +/- 0.6, both P < .001). Subacute i.c.v. leptin ([SL] 10 microg bolus) moderately but insignificantly decreased overnight food consumption (-18%) and body weight (-2.5 +/- 1.5 g). The glucose infusion rate during the final 60 minutes of the glucose clamp was 43% greater than for the vehicle group (P < .0001). SL also significantly increased GU (P < .005) and suppressed GP (P < .05) during the glucose clamp. Thus, we conclude that i.c.v. administered leptin has strong actions on the central nervous system that result in significant increases in insulin sensitivity and systemic GU, and these effects are achieved as early as overnight after leptin administration.

A comparison of torque production during dynamic strength testing of shoulder abduction in the coronal plane and the plane of the scapula.

Quantitative measurement of the shoulder abductors is important in a comprehensive assessment of shoulder muscle performance. Testing in traditionally accepted positions may be compromising to the glenohumeral static and dynamic stabilizers; therefore, there is a need to investigate testing in other planes of motion. The purpose of this study was to compare torque produced during isokinetic testing of shoulder abduction in the coronal plane and the scapular plane. Twenty female subjects with no previous shoulder pathology were tested at 90 degrees/sec and 210 degrees/sec in the coronal and scapular planes using the Cybex II isokinetic dynamometer. Both peak torque and mean peak torque of three trials were recorded. A t test for related samples (p < .05) revealed no significant difference in the peak and mean peak torque produced at each speed. Using a two-way analysis of variance with repeated measures, no significant difference was found in the peak torque produced between the two planes. However, torque production at 90 degrees/sec in both test positions was significantly higher than torque production at 210 degrees/sec (F1,19 = 159.610, p < .001). Although anatomical, functional, and clinical reasons have been proposed for performing exercise and testing procedures of the shoulder abductors in the scapular plane, the results of this study indicate that in healthy young women, there is no difference in torque production between the two planes.

Efficient encapsulation of proteins within liposomes for slow release in vivo.

A highly efficient method for the liposome encapsulation of granulocyte colony stimulating factor (rhG-CSF) was developed. The method was found to be gentle and led to no protein aggregation, denaturation or loss of protein activity. The liposomes obtained were judged to be oligolamellar based on a comparison of the actual with the theoretical trapped volumes. Slow release of encapsulated material from the liposomes was demonstrated both in vitro (90% serum, 37 degrees C) and in vivo after subcutaneous injection.

Fructose and sucrose feeding during pregnancy and lactation in rats changes maternal and pup fuel metabolism.

We examined the effects of feeding a fructose, sucrose or reference diet during gestation and lactation on blood substrate levels and insulin sensitivity in rat adipose tissue. Female rats were fed either 50% fructose or 50% sucrose purified diets or a nonpurified diet ad libitum during gestation and lactation. Fasting blood samples were taken on d 10 of gestation and one oral glucose tolerance test was conducted on d 19 of gestation, with a second test performed on the day of weaning. All dams were killed 2 d after weaning. During gestation, fructose feeding induced hyperglycemia and hypertriglyceridemia in early pregnancy (d 10) relative to sucrose-fed rats, and hypotriglyceridemia in late pregnancy (d 19) as compared with the group fed the reference diet. Compared with the reference group, sucrose feeding also caused hypotriglyceridemia during late pregnancy. Pups delivered to fructose-fed dams were hyperglycemic at birth. In comparison with the reference group, fructose-fed dams were hypoglycemic, whereas sucrose-fed dams were hypertriglyceridemic at weaning. There was no difference in each of the two oral glucose tolerance test responses between the three groups after adjusting for the baseline difference in glucose levels. However, lipid synthesis in isolated fat cells in response to insulin stimulation was significantly lower in fructose-fed and sucrose-fed rats relative to the reference group.

Intravenous keratinocyte growth factor protects against experimental pulmonary injury.

Keratinocyte growth factor (KGF) administered by intratracheal instillation is well documented to stimulate the proliferation of alveolar and bronchial cells. In the present study, intravenous KGF was also shown to stimulate the proliferation of alveolar and bronchial cells in mice and rats, although to a lesser degree than intratracheal KGF. Despite the decreased potency of intravenous KGF on pulmonary cell 5-bromo-2'-deoxyuridine incorporation compared with intratracheal KGF, intravenous KGF was very effective in preventing experimental bleomycin-induced pulmonary dysfunction, weight loss, and mortality in either mice or rats and experimental hyperoxia-induced mortality in mice. The effectiveness of intravenous administration of KGF in preventing lung injury suggests that the mechanisms of the protective effect of KGF may involve more than pulmonary cell proliferation and also suggests the potential use of systemic KGF for clinical trials in settings of pulmonary injury.