The impact of endophyte-infected fescue consumption on digital circulation and lameness in the distal thoracic limb of the horse.

This experiment was conducted to evaluate if consumption of endophyte-infected fescue alters digital circulation in the distal thoracic limb of the horse and to assess if soundness of the hooves of horses is affected by consumption of endophyte-infected fescue. Twelve American Quarter Horses (mean initial BW 459 ± 31 kg), 6 mares and 6 geldings, were used in this 90-d study that comprised high-endophyte (E+) and low-endophyte (E-) treatment groups. Fescue seed was integrated into the E+ diet at a rate sufficient to bring total ergovaline to 200 µg/kg, and endophyte-free fescue seed was incorporated into the E- diet from d 0 to 90. From d 30 to 60, native prairie hay was replaced with high- or low-endophyte fescue hay, bringing total dietary ergovaline to 280 µg/kg (E+) and 18 µg/kg (E-). From d 61 to 90, fescue seed was ground to decrease particle size. On d 0, 30, 60, and 90, Doppler ultrasonography and thermographic imaging were used to measure the diam. of the medial palmar artery, velocity of blood flow, and surface temperature of the hoof as indicators of digital circulation. Lameness examinations were conducted on the same days. There were no consistent treatment differences observed when evaluating measurements of digital circulation. On d 60, horses in the E+ treatment group showed increased hoof sensitivity in the left limb (P = 0.02). These horses tended to have increased hoof sensitivity when both thoracic limbs were averaged (P = 0.06), and they demonstrated increased lameness during longeing (P = 0.08). Data indicated that mares may have increased digital circulation, regardless of treatment, compared with geldings (P ≤ 0.05). Heavier horses also had greater arterial diam., velocity of blood flow, and hoof temperature than lighter BW horses (P ≤ 0.05) on d 30, 60, and 90 at time points that ranged from 90 to 180 min after feeding. Although horses consuming the E+ diet demonstrated increased lameness, especially on d 60, compared with horses consuming the E- diet, the measures of digital circulation did not support the hypothesis that digital circulation was reduced. Because of observed lameness issues, limiting the access of horses to endophyte-infected fescue may be prudent.

A trick of the light: the optical properties of living cytoplasm which can mislead.

Our understanding of the dynamic chemical changes within living cells has increased enormously as a direct result of imaging and manipulating techniques which rely on the use of light to penetrate the cell. These optical techniques are at the intersection of the three sciences: physics, chemistry and biology. However, the understanding of the physics of illumination (e.g. lasers, confocal microscopy) and the chemistry of fluors (synthetic and protein) is way ahead of the understanding of the biological interface posed by the cell itself. In this critical review we will show that ignoring the optical properties of living cells can lead to serious errors of interpretation and that even seemingly compelling images can result from a "trick of the light".

Optical complexities of living cytoplasm--implications for live cell imaging and photo-micromanipulation techniques.

The ability to manipulate the intracellular environment within living cells and to monitor the cytosolic chemical changes which occur during cell stimulation has lead to major advances in our understanding of how cells read and respond to their environment. Perhaps the most powerful suite of techniques for achieving these dual objectives is based on the use of light (photons). Because cells are 'transparent', light has been used to both interrogate and manipulate the chemistry inside living cells, exploiting technical advances in both the physical and biochemical sciences. However, cells are neither transparent nor homogeneous with respect to their optical properties. The interface between light and the living cell cytoplasm thus represent an important, yet largely ignored, interface. There has been no review of the optical properties of cytoplasm and little discussion about how the optical properties of living cytoplasm influence the outcome of such measurements and manipulations. In this short review, we discuss the importance of understanding the optical properties of cytoplasm for such techniques and how imperfections in experimental interpretation can arise.

Reduced iC3b-mediated phagocytotic capacity of pulmonary neutrophils in cystic fibrosis.

Cystic fibrosis (CF) is characterized by a neutrophil-dominated chronic inflammation of the airways with persistent infections. In order to investigate whether neutrophils contribute to an inadequacy in the pulmonary defence mechanism, the phagocytic activity of pulmonary and peripheral blood neutrophils from CF and non-CF respiratory patients were compared. Neutrophils were isolated from both the blood and bronchoalveolar lavage fluid of 21 patients with CF (12 male, 9 female; mean age 7.5 years, range 0.25-16.4 years) and 17 non-CF subjects (9 male, 8 female; mean age 5.4 years, range 0.2-13.1 years). The ex vivo phagocytic rate of normal pulmonary neutrophils to internalize zymosan particles opsonized with iC3b was faster than that of circulating neutrophils (P < 0.05), but the maximum capacity (9 particles/cell) was similar. In contrast, pulmonary neutrophils from patients with CF had a lower phagocytic capacity than circulating neutrophils either from the same patients or from normal subjects. This deficiency could not be attributed to (i) the cell surface density of CR3 (CD18/CD11b) receptors, which were not significantly different between the other groups (ii) the signalling ability of the CR3 receptors, using cytosolic free Ca(2+) signalling as the receptor activity read-out or (iii) a decrease in cellular ATP concentration. As CFTR was not detectable on neutrophils from any source by either histochemistry or Western blotting, it was concluded that the reduced phagocytic capacity was not the direct result of a CFTR mutation, but was attributed to a failure of neutrophil phagocytic priming during translocation into the CF lung.

Microreactors for chemical synthesis.

The advances of the past few years in microreactors have demonstrated that the miniaturization of chemistry has significant advantages with respect to cost, safety, throughput, kinetics and scale-up. The use of chemical microreactors for catalytic oxidations, heterocyclic syntheses and photochemical reactions has illustrated the utility and benefits for both chemical discovery and chemical development applications.

Techniques for measuring and manipulating free Ca2+ in the cytosol and organelles of neutrophils.

Ca(2+) signalling in neutrophils is important for triggering and coordinating the behaviour of neutrophils. Fluorescent probes for cytosolic free Ca(2+) concentration, e.g., fura2 and fluo3, have been widely used in neutrophils. These probes can be used to monitor Ca(2+) in the cytosol, the nucleus, near the plasma membrane and theoretically within Ca(2+) storage organelles. The longer wavelength indicators, e.g., fluo3 and calcium green, can be used confocally to monitor subcellular Ca(2+) changes in the cytosol of neutrophils and in the nucleus. Confocal techniques also permit "impossible views" imaging of Ca(2+) and newer scanning techniques promise very fast temporal resolution. Techniques using chlortetracycline (CTC) and DiOC(6)(3) are also described for monitoring the position of Ca(2+) storage sites in neutrophils and for manipulating their activity. Thus, in this review, a spectrum of new (and older) optical techniques are presented which are useful for measuring, monitoring and manipulating cytosolic free Ca(2+) concentration and Ca(2+) storage in neutrophils. With these techniques, it is hoped that more insight will be gained into both the mechanism of and the consequences of Ca(2+) signalling in neutrophils.

Physical growth of low birthweight infants in the first year of life: impact of maternal behaviors.

Physical growth of preterm infants relates to many medical factors, such as birthweight, severity of medical illnesses, and nutritional status. We previously reported that maternal behaviors influence developmental outcomes in low birthweight infants (birthweight < 1600 g); we now hypothesize that maternal behaviors also influence physical somatic growth in low birthweight (LBW) infants. We serially followed 218 mother-infant pairs from birth through 12 months of age. One-hundred thirteen LBW infants were categorized based on severity of early medical complications. Low Risk infants (LR, n = 71) had acute respiratory distress and/or grade 1-2 intraventricular hemorrhage (IVH), or grade 3 IVH without hydrocephalus. High Risk infants (HR, n = 42) had chronic lung disease, grade 3 IVH with hydrocephalus or grade 4 IVH, and/or periventricular leukomalacia. We also studied 105 socioeconomic (SES) matched Full Term (FT) controls. Maternal behaviors were assessed during home visits with global ratings of Warm Sensitivity and Punitiveness. Infant weight was measured at birth and at 38 weeks, 6 months and 12 months corrected gestational age. We examined alternative expressions of weight growth across the three groups by developing the Weight Quotient (WQ), which is the ratio of actual measured weight to the median weight for age. For each infant the regression of the WQ ratio against correct gestational age was analyzed. We used a General Linear Model to compare the relation of the maternal variables to the weight quotients for the three groups. We determined the catch up growth as the slope of each regression. Results indicated that higher levels of maternal Punitiveness were related to slower rates of growth for High Risk (R2 = 0.36), but not Low Risk or Full Term. For maternal Warm Sensitivity (R2 = 0.36), there were significant (P < 0.05) inverse relations with weight gain growth for the Full Term infants. These data suggest that some maternal behaviors are related to the growth of term and premature infants, although the mechanisms through which this occurs is unclear.

Neonatal presentation of Gordon syndrome.

Gordon syndrome, the association of hypertension with hyperkalemic acidosis, has been described in older children and adults. We report an affected family in which two of the members had exhibited the metabolic manifestations of the disease since infancy. Both patients responded well to thiazides. To our knowledge, these are the youngest patients with documented cases of Gordon syndrome.

The impact of polystyrene resins in solid-phase organic synthesis.

A major objective of the DIVERSOMER technology is to provide pure and characterized compounds for biological testing in order to prevent 'false negatives' in our libraries. On several occasions, analysis of the final products by 1H-NMR and MS, has revealed by-products from the polystyrene solid support. Subsequently, three alternative methods were studied to remove polystyrene by-products; (i) prewashing of the resin prior to execution of the synthesis; (ii) pretreatment of the resin with the cleavage conditions consistent with the solid-phase synthesis reaction scheme; and (iii) parallel purification.

Radiographic evaluation of native anterior cruciate ligament attachments and graft placement for reconstruction. A cadaveric study.

We examined seven cadaveric knees to determine the radiographic location of the native anterior cruciate ligament insertion sites as well as the location of tunnels used in anterior cruciate ligament reconstruction. Posteroanterior and lateral views at several flexion angles were taken with radiopaque markers around the insertions of the native anterior cruciate ligament and subsequent reconstruction tunnels. The femoral insertion was best seen on the 60 degrees notch view. On the lateral view, the femoral tunnel was easily seen as it crossed the roof of the intercondylar notch; however, because of the angle of the tunnel, the actual entrance into the knee may be well distal and anterior to this location. The tibial insertion and tunnel were easily seen at any flexion angle. The center of the insertion was 40% of the tibial diameter from the anterior margin. The lateral view in extension allowed determination of the tibial tunnel's location in relation to the intercondylar notch roof, but by itself did not allow accurate determination of the femoral tunnel's position. Notch and extension lateral radiographs together provided sufficient information for evaluation of anterior cruciate ligament graft position in a convenient, cost-effective format. Neither view by itself provides enough information to evaluate the position of the graft.

Semen alloantigens and lymphocytotoxic antibodies in AIDS and ICL.

More than 90% of people with AIDS develop circulating immune complexes (CICs) and lymphocytotoxic antibodies (LCTAs). Animals infected with HIV, however, never display CICs or LCTAs, and remain healthy. Similarly, HIV-infected people who do not develop CICs or LCTAs also do not progress to AIDS. The appearance of CICs and LCTAs is, however, highly prognostic for AIDS and death. Since HIV infection does not, per se, lead to the development of CICs and LCTAs, other causes are likely. One such cause, for which both epidemiologic and experimental evidence exists, is semen. Semen components include sperm, seminal fluid, lymphocytes, and sometimes infectious agents, including HIV, mycoplasmas, and herpes and hepatitis viruses, all of which independently cause immune suppression. Extensive evidence demonstrates sperm (and various viruses) contains many proteins mimicking the CD4 protein of T-helper cells, while HIV, mycoplasmas, and seminal fluid mimic class II MHC proteins of other lymphocytes. We identify a large number of protein sequences that display such mimicry using computer homology searching, and demonstrate experimentally that sperm antibodies specifically precipitate antibodies against class II MHC mimics such as mycoplasmas, which in turn precipitate antibodies to lymphocyte antigens. These data prove that immunologic exposure to sperm and lymphocytes (as may occur in receptive anal intercourse, needle sharing, or blood transfusions) is theoretically capable of initiating lymphocytotoxic autoimmunity. Such autoimmunity may play a significant role in the pathogenesis of AIDS, and will need to be addressed clinically in high risk individuals regardless of HIV status and regardless of the success of anti-HIV prophylaxis and treatment.

CD4 similarity to proteins of infectious agents in AIDS and their role in autoimmunity.

Lymphocytotoxic autoimmunity (LA) is ubiquitous in AIDS. Its causes are unknown. We report that significant amino acid sequence similarities exist between the proteins of infectious organisms associated with AIDS and the CD4 protein of T-helper lymphocytes. These included: HIV, cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex viruses (HSV), Varicella Zoster virus (VZV), Escherichia coli, Mycobacteria, Mycoplasmas, Plasmodium, and Staphylococcus. It has been reported previously that HIV proteins have significant similarities with human class II MHC (HLA class II) proteins. Since CD4 and HLA class II proteins are chemically complementary, pairs of homologous antigens will also be complementary. It follows that concurrent infections with CD4 and HLA class II-homologous antigens will result in idiotype-antiidiotype antibody pairs that cannot distinguish 'self' from 'nonself', that acts as lymphocytotoxins, and form circulating immune complexes. Thus, combined HIV-CMV, HIV-EBV, HIV-HBV, HIV-mycoplasma, or other appropriate infectious pairs may suffice to trigger LA in AIDS.

"Diversomers": an approach to nonpeptide, nonoligomeric chemical diversity.

Solid-phase chemistry, organic synthesis, and an apparatus for multiple, simultaneous synthesis have been combined to generate libraries of organic compounds ("diversomers"). Arrays of compounds were synthesized over two to three steps incorporating chemically diverse building blocks on a polystyrene-based solid support in a multiple, simultaneous manner. The generality of this approach is illustrated by the syntheses of dipeptides, hydantoins, and benzodiazepines.

Treatment of rosacea: topical clindamycin versus oral tetracycline.

BACKGROUND: A new topical antibiotic preparation, clindamycin in a lotion base, was compared with oral tetracycline in the treatment of rosacea. Forty-three patients clinically diagnosed as having rosacea were examined in an investigator-blinded study. METHODS: Patients used topical clindamycin lotion applied twice daily or the usual oral dose of tetracycline hydrochloride (250 mg four times a day for 3 weeks, then 250 mg twice a day for the remaining 9 weeks). Patients' lesions were examined clinically at 3-week intervals over a period of 12 weeks. RESULTS: Topical clindamycin treatment produced similar clinical results to oral tetracycline and was superior in the eradication of pustules. CONCLUSIONS: These results show topical clindamycin in a lotion base to be a safe and effective alternative to oral tetracycline therapy in the treatment of rosacea.

Interferon-gamma induced by administration of recombinant interleukin-2 to patients with cancer: kinetics, dose dependence, and correlation with physiological and therapeutic response.

The administration of recombinant interleukin-2 as an i.v. bolus at dose levels of from 1 to 30 MIU/m2 to patients with cancer induces easily measurable serum interferon-gamma levels of 1 to 500 U/ml. After a lag of 1 h, interferon-gamma rises to a maximum at 4 h and then slowly decreases. The peak values are poorly correlated with the dose of interleukin-2, and thus must be also be dependent on other factors. Successive administration of interleukin-2 typically increases the peak level of interferon-gamma fourfold, but does not diminish the lag period. Peak levels of interferon-gamma are also increased by concurrent administration of interferon-beta with interleukin-2. Continuous i.v. infusion of 1.5 to 20 MIU/m2 of interleukin-2/day results in interferon-gamma levels of 1 to 7 U/ml. Hypotension, which is characteristically associated with interleukin-2 administration, is correlated with interferon-gamma levels in only some patients. There was no apparent correlation between tumor regression and serum interferon-gamma levels.

Nursing assessment of the skin and dermatologic lesions.

An accurate assessment of the skin and dermatologic lesions depends on the nurse, who is directly involved with patient care. However, demands of new technology, which supports an increasingly debilitated and aged patient population, makes it more difficult for the nurse to meet high standards of skin maintenance at a time when it should be a priority. Nursing assessment skills need not be extensive but confined to descriptively brief and familiar terms. Basic knowledge of the most common skin lesions allows the nurse to document in accurate and concise terms instead of nondescript generalizations, such as "rash."

DMSO is a substrate for chloroperoxidase.

Dimethyl sulfoxide has been used as a nonaqueous organic solvent in haloperoxidase reactions. However, it has been found that this solvent is not inert under chloroperoxidase reaction conditions, forming the halosulfoxide, the sulfone, and the halosulfone. The biological significance of this finding is briefly discussed.

Novel haloperoxidase reaction: synthesis of dihalogenated products.

The enzymatic synthesis of vicinal, dihalogenated products from alkenes and alkynes is described. The enzymatic reaction required an alkene or alkyne, dilute hydrogen peroxide, a haloperoxidase, and molar amounts of halide ions. Vicinal dichloro, dibromo, and diiodo products could be formed. A hydroxyl group on the carbon adjacent to the carbon-carbon double or triple bond lowered the halide ion concentration needed to produce the dihalo product. This reaction offers one explanation for the origin of natural, vicinal, dihalogenated products, such as those found frequently in marine microogranisms.

Production of Epoxides from alpha,beta-Halohydrins by Flavobacterium sp.

The relative activity of Flavobacterium whole cells on the enzymatic synthesis of epoxides from alpha,beta-chlorohydrins, -bromohydrins, and -iodohydrins is described.