Rotational diffusion of spherical colloids close to a wall.

There is currently no experimental technique available to probe spatially resolved rotational diffusion of nanoparticles in the vicinity of a wall. We present the first experimental study of rotational diffusion of small spherical colloids, using dynamic evanescent wave scattering. A setup is used where the wave vector components parallel and perpendicular to the wall can be varied independently, and an expression is derived for the first cumulant of the intensity correlation function in VH evanescent wave geometry for optically anisotropic spheres. The experimental results are in agreement with theoretical predictions that take particle-wall hydrodynamic interactions into account.

Foliar-Applied Small Molecule that Suppresses Biofilm Formation and Enhances Control of Copper-Resistant Xanthomonas euvesicatoria on Pepper.

We report a small molecule additive, a member of the 2-aminoimidazole (2AI) group that is an analogue of the marine sponge natural product oroidin that suppresses resistance of Xanthomonas euvesicatoria to copper and decreases biofilm formation in an in vitro system. In laboratory experiments, 2AI combined with copper reduced both bacterial multiplication in broth and bacterial recovery on pepper leaf discs of a copper-resistant strain of X. euvesicatoria to a level close to that of a copper-sensitive strain. Compound 2AI used alone exhibited minimal bactericidal activity. In 3 years of field experiments, when combined with a copper-containing material, copper hydroxide (Kocide 3000), and other antibacterial materials, these spray mixtures resulted in decreased bacterial spot foliar disease and increased fruit yields using hybrid bell pepper (Capsicum annuum) cultivars and copper-resistant strains of X. euvesicatoria. This study demonstrates the concept for using small molecules as additives to antibacterial compounds at nonbactericidal concentrations under field conditions that, in the laboratory, were demonstrated to suppress bacterial biofilms and copper-resistant strains.

Insulin-like growth factors I and II are produced in the metanephros and are required for growth and development in vitro.

The role(s) of one family of polypeptide growth factors in a developing organ system was examined. Renal anlagen (metanephroi) were surgically removed from 13-d-old rat embryos and grown in organ culture for up to 6 d. Over this period of time when placed in serum-free defined media, the metanephroi increased in size and morphologic complexity. Messenger RNAs for both insulin-like growth factors (IGFs), IGF I and IGF II, were present in the metanephroi. Immunoreactive IGF I and IGF II were produced by the renal anlagen and released into culture media. Levels were relatively constant during the 6 d in culture and averaged 3.5 X 10(-9) M IGF I and 8.3 X 10(-9) M IGF II in media removed from metanephroi after contact for 24 h. IGF binding protein activity was not detected in culture media. Growth and development of metanephroi in vitro was prevented by the addition of anti-IGF I or anti-IGF II antibodies to organ cultures. IGF II produced by metanephroi was active in an IGF II biological assay system and addition of anti-IGF II receptor antibodies to organ cultures prevented growth and development, consistent with the action of IGF II in metanephroi being mediated via the IGF II receptor. The data demonstrate production of both IGF I and IGF II by developing rat metanephroi in organ culture. Each of these peptides is necessary for growth and development of the renal anlage to take place in vitro. Our findings suggest that both IGF I and IGF II are produced within the developing metanephros in vivo and promote renal organogenesis.

Insulin-like growth factor I gene expression in isolated rat renal collecting duct is stimulated by epidermal growth factor.

The renal collecting duct is a site of insulin-like growth factor I (IGF I) synthesis. Epidermal growth factor (EGF) is also synthesized within the kidney in the thick ascending limb of Henle's loop and the distal tubule. EGF has been shown to regulate IGF I expression in nonrenal tissues. To shed light upon a role of EGF in intrarenal regulation of IGF I gene expression, plasma membranes prepared from collecting ducts isolated from rat kidney and collecting ducts themselves were incubated in the presence and absence of recombinant human EGF (hEGF). hEGF enhanced phospholipase C activity in collecting duct plasma membranes establishing the potential for EGF signal transduction at this site. Inclusion of hEGF in suspensions of collecting ducts increased production of immunoreactive IGF I in a concentration-dependent manner. Production was stimulated significantly by addition of 10(-8) or 10(-6) M hEGF to suspensions for 2 h. Levels of IGF I mRNA in collecting ducts were increased 2.8-fold after incubation with 10(-6) M hEGF in vitro. Our findings demonstrate a direct action of hEGF to enhance collecting duct IGF I gene expression in vitro. Such enhancement is likely to reflect an effect of EGF to stimulate IGF I production in the collecting duct of the intact kidney. Since EGF is produced in kidney, our findings are consistent with intrarenal paracrine regulation of IGF I gene expression by EGF.

Two core promotor mutations identified in a hepatitis B virus strain associated with fulminant hepatitis result in enhanced viral replication.

Viral mutations have been implicated in alteration of the biological phenotype of hepatitis B virus (HBV). We recently cloned and sequenced the viral genome of an HBV strain associated with an outbreak of fulminant hepatitis (FH strain). The FH strain contained numerous mutations in all genomic regions and was functionally characterized by a more efficient encapsidation of pregenomic RNA leading to highly enhanced replication. To define the responsible mutation(s) for the enhanced replication, we introduced individual mutations of the FH strain into a wild-type construct by oligonucleotide-directed mutagenesis. Analysis of viral replication showed that two adjacent mutations in the HBV core promotor (C to T at nucleotide 1768 and T to A at nucleotide 1770) led to high level replication. Similar to the FH strain, this mutant displayed the phenotype of enhanced encapsidation of pregenomic RNA. Functional studies in an encapsidation assay demonstrated that the identified mutations resulted in a minor increase of pregenomic RNA transcription (two- to threefold) and a major transcription-independent enhancement (> 10-fold) of viral encapsidation. Our results demonstrate that the two adjacent mutations in the HBV core promotor region are responsible for the enhanced replication of the FH strain. These two mutations, outside the previously described encapsidation signal, core, and polymerase polypeptides, appeared to affect a novel genetic element involved in viral encapsidation.

Cloning and unusual expression profile of the aldolase B gene from Atlantic salmon.

A full-length clone of the aldolase B gene has been isolated from a cDNA library constructed from liver of Atlantic salmon (Salmo salar). Sequencing showed that the clone encodes a typical aldolase B, possessing a number of amino acid residues which are seen in aldolase B, but not in other aldolase isoforms. RT-PCR analysis showed that the gene is expressed in liver, kidney and intestine as expected. However, in contrast to mammalian and avian aldolase B, expression was also found in a number of other tissues. Levels of aldolase B mRNA in liver and kidney were not significantly altered during smoltification, the transformation of freshwater-dwelling salmon (parr) into saltwater-adapted salmon (smolts).

Diagnosing the tight building syndrome.

Formaldehyde is but one of many chemicals capable of causing the tight building syndrome or environmentally induced illness (EI). The spectrum of symptoms it may induce includes attacks of headache, flushing, laryngitis, dizziness, nausea, extreme weakness, arthralgia, unwarranted depression, dysphonia, exhaustion, inability to think clearly, arrhythmia or muscle spasms. The nonspecificity of such symptoms can baffle physicians from many specialties. Presented herein is a simple office method for demonstrating that formaldehyde is among the etiologic agents triggering these symptoms. The very symptoms that patients complain of can be provoked within minutes, and subsequently abolished, with an intradermal injection of the appropriate strength of formaldehyde. This injection aids in convincing the patient of the cause of the symptoms so he can initiate measures to bring his disease under control.

Characterization of cationic vector-based gene delivery vehicles using isothermal titration and differential scanning calorimetry.

Within the past 10 years, major advances in the design and development of differential scanning calorimeters (DSC) (1) and isothermal titration calorimeters (ITC) (2) have resulted in an unparalleled level of sensitivity, stability, and reproducibility in calorimetric measurements of large molecules. These improvements have allowed the thermal stability and ligand binding processes of biological macromolecules to be thermodynamically characterized with speed, accuracy, and convenience. With their increasing commercial availability, experiments that were previously limited to specialist calorimetry laboratories can now be routinely performed by most investigators.

Cloning of the Atlantic salmon (Salmo salar) estrogen receptor-alpha gene.

A cDNA clone encoding most of an Atlantic salmon (Salmo salar) estrogen receptor (ER) was obtained from a liver cDNA library and the remainder of the coding sequence from the gene was isolated from a genomic library. Sequence comparisons showed that the cloned gene represents ER-alpha. Expression of the ER-alpha gene in male and female salmon parr was analysed by RT-PCR. Highest expression was found in brain and liver, with lower levels of ER-alpha mRNA present in all other tissues tested. There was little difference in expression of ER-alpha between male and female.

The prevalence of religious coping among persons with persistent mental illness.

OBJECTIVE: The purpose of this study was to examine the prevalence of religious coping among persons with persistent mental illness and to gain a preliminary understanding of the relationship between religious coping and symptom severity and overall functioning. METHODS: A total of 406 individuals who were diagnosed as having a mental illness and who were patients at one of 13 Los Angeles County mental health facilities completed a survey consisting of the Religious Coping Index, the Symptom Checklist 90-R (SCL-90), the Global Assessment of Functioning (GAF) scale, and a 48-item demographic questionnaire. RESULTS: More than 80 percent of the participants used religious beliefs or activities to cope with daily difficulties or frustrations. A majority of participants devoted as much as half of their total coping time to religious practices, with prayer being the most frequent activity. Specific religious coping strategies, such as prayer or reading the Bible, were associated with higher SCL-90 scores (indicating more severe symptoms), more reported frustration, and a lower GAF score (indicating greater impairment). The amount of time that participants devoted to religious coping was negatively related to reported levels of frustration and scores on the SCL-90 symptom subscales. CONCLUSIONS: The results of the study suggest that religious activities and beliefs may be particularly compelling for persons who are experiencing more severe symptoms, and increased religious activity may be associated with reduced symptoms. Religion may serve as a pervasive and potentially effective method of coping for persons with mental illness, thus warranting its integration into psychiatric and psychological practice.

The microbiological and technological properties of bruised beef.

Currently, bruised beef is condemned under meat hygiene regulations within Australia. The aim of this study was to determine whether bruised beef was microbiologically and technologically sound and therefore suitable for use in processed meat products. Paired samples of bruised and unbruised beef from sides processed through three abattoirs were collected over an 18 month period, and analysed for a range of microbiological, chemical and physical parameters. There were no differences in the microbiological loads or growth rates of micro-organisms, and only small differences in the compositional and processing properties between the two tissues. There appears to be no microbiological or technological reason for the condemnation of bruised beef.

The effect of bruised beef addition on the quality of processed meat products.

The aim of this study was to determine the levels of bruised beef that could be incorporated into processed meat products without detrimental effects on product quality. Bruised beef was incorporated into fresh sausages, Devon and semi-dry salami, and compared to products containing unbruised beef. Up to 30%, 25% and 65% of the unbruised beef in fresh sausages, Devon and semidry salami respectively can be replaced with bruised beef with no detrimental effect on product quality (as assessed by a sensory panel), either initially or over the shelf-life of the product at 4°C. The level of bruised beef which can be incorporated into meat products is predominantly limited by its effect on product colour. The microbiological and compositional qualities of meat products containing bruised beef are similar to those containing unbruised beef.

Aging, yielding, and shear banding in soft colloidal glasses.

Soft colloidal interactions in colloidal glasses are modeled using suspensions of multiarm star polymers. Using a preshearing protocol that ensures a reproducible initial state ("rejuvenation" of the system), we report here the evolution of the flow curve from monotonically increasing to one dominated by a stress plateau, demonstrating a corresponding shear-banded state. Phenomenological understanding is provided through a scalar model that describes the free-energy landscape.

Long-term engraftment following transplantation of pig pancreatic primordia into non-immunosuppressed diabetic rhesus macaques.

BACKGROUND: Transplantation therapy for human diabetes is limited by a shortage of donor organs, and transplant function diminished over time by cell death and limited potential for expansion of beta cells in pancreas or islets. Outcomes are complicated by immunosuppression. A way to overcome supply and expansion problems is to xenotransplant embryonic tissue. Previously, we have shown that beta cells originating from embryonic day (E) 28 (E28) pig pancreatic primordia transplanted into the mesentery of streptozotocin (STZ)-diabetic (type 1) Lewis rats or Zucker Diabetic Fatty (ZDF) diabetic (type 2) rats engraft and normalize glucose tolerance without the need for host immune-suppression. METHODS: In this study, we transplant E28 pig pancreatic primordia in the mesentery of STZ-diabetic rhesus macaques. RESULTS: Long-term engraftment of pig beta cells within liver, pancreas and mesenteric lymph nodes post-transplantation of E28 pig pancreatic primordia into STZ-diabetic rhesus macaques is demonstrated by electron microscopy, positive immune-histochemistry for insulin, and positive RT-PCR and in situ hybridization for porcine proinsulin mRNA. Insulin requirements were reduced in one macaque followed over 22 months post-transplantation and porcine insulin detected in plasma using sequential affinity chromatography, HPLC and mass spectrometry. Of potential importance for application of this transplantation technology to treatment of diabetes in humans and confirmatory of our previous findings in Lewis and ZDF rats, no host immunosuppression is required. CONCLUSIONS: Under selected circumstances, pancreatic primordia elicit a muted immune response relative to more differentiated tissue, such that engraftment occurs in non-immunosuppressed hosts. Our findings that pig pancreatic primordia engraft long-term in non-immunosuppressed STZ-diabetic rhesus macaques establishes the potential for their use in human diabetics.

A comparison of commercially available mold survey services.

Plates from the County Laboratory, Hollister-Stier and our lab were simultaneously placed in the same locations. Comparisons show increased yield comes from a combination of the latter two and the greatest over-all yield came from our lab. Also multiple-placed plates in the same room show the flora is not static.

A 13-month work-leisure-sleep environment fungal survey.

Thirty plates per month for 13 months were exposed in patients' work-leisure-sleep environments in central New York State. Results show the months of highest mold prevalence in decreasing order were October, September, May and July. These months are also typically our high pollen months. The categories of highest prevalence in decreasing order were yeats, mycelia sterilia, Cladosporium, Penicillium, Rhodotorula, bacteria, Alternaria, Aureobasidium, Epicoccum, Aspergillus, Geotrichum, Basidiomycetes, Actinomycetes and Phoma. These were present in at least 14% of all 390 plates. The present study includes a discussion of the value of these findings in an allergy practice.

Epidermal growth factor binding and stimulation of inositol trisphosphate production in basolateral membranes from dog kidney.

To ascertain whether epidermal growth factor (EGF) receptors are present in proximal tubular basolateral membranes from dog kidney and whether the growth factor activates phospholipase C at this site, we measured binding of 125I-EGF in isolated membranes and determined whether incubation of the membranes with EGF results in generation of inositol trisphosphate. Specific binding of 125I-EGF to basolateral membranes was observed that was half-maximally inhibited by approximately 7 x 10(-10) M EGF. The specific binding capacity of basolateral membranes for EGF averaged 45.9 fmol/mg protein. 125I-EGF was crosslinked to 2 proteins in basolateral membranes with M(r)s of 170,000 and 150,000. EGF stimulated phosphorylation of a 170,000 M(r) protein. Incubation of basolateral membranes with EGF stimulated inositol trisphosphate production in a concentration-dependent manner. We conclude that EGF activates a phospholipase C activity that cleaves phosphatidylinositol 4,5-bisphosphate within the basolateral membrane.

Transplantation of metanephroi after preservation in vitro.

To determine whether transplanted metanephroi grow, differentiate, and function in hosts after preservation in vitro, we implanted metanephroi from embryonic day 15 (E15) Sprague-Dawley rat embryos into the omentum of nonimmunosuppressed uninephrectomized Sprague-Dawley (host) rats. Metanephroi were either implanted directly or suspended in ice-cold University of Wisconsin (UW) preservation solution with or without added growth factors for 3 days before implantation. The size and extent of tissue differentiation preimplantation of E15 metanephroi implanted directly were not distinguishable from the size and differentiation of metanephroi preserved for 3 days. In contrast, E16 metanephroi were larger than E15 metanephroi preserved for 3 days. E16 metanephroi or E13 metanephroi grown in organ culture for 3 days contained more differentiated nephron structures than those in E15 metanephroi preserved for 3 days. By 4 wk posttransplantation, metanephroi that had been preserved for 3 days had grown and differentiated such that glomeruli, proximal and distal tubules, and collecting ducts with normal structure had developed. At 12 wk posttransplantation, inulin clearances of preserved metanephroi were comparable to those of metanephroi that had been implanted directly. Addition of growth factors to the UW solution enhanced inulin clearances. Here we show for the first time that functional kidneys develop from metanephroi transplanted from rat embryos to adult rats after as long as 3 days of preservation in vitro.