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Biomedical subjects

Richard Gross

Publications and source records attributed to Richard Gross.

9 recordsLinked to original sources
PubMed2006

Influence of dimethyl sulfoxide on extracellular enzyme production by Pleurotus ostreatus.

Dimethyl sulfoxide (DMSO) is commonly used as a co-solvent to dissolve poorly water-soluble biologically active agents to assess their biological activities such as for enzyme induction. The question addressed was whether DMSO can be assumed to be an inert co-solvent. The influence of DMSO on the production of extracellular enzymes by Pleurotus ostreatus was investigated. DMSO functioned as either an inducer or a repressor, depending on the enzyme studied. The production of laccase and endo-1,4-beta-xylanase increased by 29 and 250%, respectively, in presence of DMSO. However, DMSO repressed the activities of manganese peroxidase, beta-glucosidase, beta-xylanase, and endo-1,4-beta-glucanase by 30, 33, 99 and 16%, respectively. These results raise concerns about the interpretation of bioactivity measurements when DMSO is assumed to function as an inert co-solvent to solubilize water-insoluble molecules.

Biotechnology↗
PubMed2006

Sophorolipids block lethal effects of septic shock in rats in a cecal ligation and puncture model of experimental sepsis.

OBJECTIVE: Sophorolipids, a family of natural and easily chemoenzymatically modified microbial glycolipids, are promising modulators of the immune response. The potential of the therapeutic effect of sophorolipids was investigated in vivo in a rat model of sepsis and in vitro by analysis of nitric oxide and cytokine production. DESIGN: Prospective, randomized animal study. SETTING: Experimental laboratory. SUBJECTS: Male Sprague-Dawley rats, 200-240 g. INTERVENTIONS: Intra-abdominal sepsis was induced in vivo in 166 rats via cecal ligation and puncture (CLP); 60 rats were used to characterize the model. The remaining rats were treated with sophorolipids or vehicle (dimethylsulfoxide [DMSO]/physiologic saline) by intravenous (iv) tail vein or intraperitoneal (IP) injection immediately post-CLP (25/group). Survival rates were compared at 36 hrs after surgery. In vitro, macrophages were cultured in lipopolysaccharide (LPS) +/- sophorolipid and assayed for nitric oxide (NO) production and gene expression profiles of inflammatory cytokines. In addition, splenic lymphocytes isolated from CLP rats +/- sophorolipid treatment (three per group) were analyzed for cytokine production by RNase protection assay. MEASUREMENTS AND MAIN RESULTS: CLP with 16-gauge needles optimized sepsis induction and resultant mortality. Sophorolipid treatment improved rat survival by 34% (iv) and 14% (IP) in comparison with vehicle controls (p < .05 for iv treatment). Sophorolipids decreased LPS-induced macrophage NO production by 28% (p < .05). mRNA expression of interleukin (IL)-1beta was downregulated by 42.5 +/- 4.7% (p < .05) and transforming growth factor (TGF)-beta1 was upregulated by 11.7 +/- 1.5% (p < .05) in splenocytes obtained 6 hrs postsophorolipid treatment. LPS-treated macrophages cultured 36 hrs with sophorolipids showed increases in mRNA expression of IL-1alpha (51.7%), IL-1beta (31.3%), and IL-6 (66.8%) (p < .05). CONCLUSIONS: Administration of sophorolipids after induction of intra-abdominal sepsis significantly decreases mortality in this model. This may be mediated in part by decreased macrophage NO production and modulation of inflammatory responses.

Animals↗
PubMed2005

Effect of Iyengar yoga therapy for chronic low back pain.

Low back pain is a significant public health problem and one of the most commonly reported reasons for the use of Complementary Alternative Medicine. A randomized control trial was conducted in subjects with non-specific chronic low back pain comparing Iyengar yoga therapy to an educational control group. Both programs were 16 weeks long. Subjects were primarily self-referred and screened by primary care physicians for study of inclusion/exclusion criteria. The primary outcome for the study was functional disability. Secondary outcomes including present pain intensity, pain medication usage, pain-related attitudes and behaviors, and spinal range of motion were measured before and after the interventions. Subjects had low back pain for 11.2+/-1.54 years and 48% used pain medication. Overall, subjects presented with less pain and lower functional disability than subjects in other published intervention studies for chronic low back pain. Of the 60 subjects enrolled, 42 (70%) completed the study. Multivariate analyses of outcomes in the categories of medical, functional, psychological and behavioral factors indicated that significant differences between groups existed in functional and medical outcomes but not for the psychological or behavioral outcomes. Univariate analyses of medical and functional outcomes revealed significant reductions in pain intensity (64%), functional disability (77%) and pain medication usage (88%) in the yoga group at the post and 3-month follow-up assessments. These preliminary data indicate that the majority of self-referred persons with mild chronic low back pain will comply to and report improvement on medical and functional pain-related outcomes from Iyengar yoga therapy.

Adult↗
PubMed2005

Sophorolipids, microbial glycolipids with anti-human immunodeficiency virus and sperm-immobilizing activities.

The increased incidence of human immunodeficiency virus (HIV)/AIDS disease in women aged 15 to 49 years has identified the urgent need for a female-controlled, efficacious, and safe vaginal topical microbicide. To meet this challenge, sophorolipid (SL) produced by Candida bombicola and its structural analogs have been studied in this report for their spermicidal, anti-HIV, and cytotoxic activities. The sophorolipid diacetate ethyl ester derivative is the most potent spermicidal and virucidal agent of the series of SLs studied. Its virucidal activity against HIV and sperm-immobilizing activity against human semen are similar to those of nonoxynol-9. However, it also induced enough vaginal cell toxicity to raise concerns about its applicability for long-term microbicidal contraception. Its structure-activity relationship has been established for creating new analogs with less cytotoxicity and higher activity.

Anti-HIV Agents↗
PubMed2004

Supramolecular assemblies of a naturally derived sophorolipid.

Acidic sophorolipid (SL) molecules derived from yeasts represent a novel type of asymmetrical bolaamphiphiles due to their unique structural features that include an asymmetrical polar head size (disaccharide vs COOH), a kinked hydrophobic core (cis-9-octadecenoic chain), and a non-amide polar-nonpolar linkage. Light microscopy, small- and wide-angle X-ray scattering, FT-IR spectroscopy, and dynamic laser light scattering were used to investigate the supramolecular structures of the self-assembled aggregates of SL molecules at different pH values. In acidic conditions (pH < 5.5), giant twisted and helical ribbons of 5-11 microm width and several hundreds of micrometers length were observed for the first time. Increase in solution pH values slowed ribbon formation, decreased ribbon yield, and increased the helicity and entanglements of the giant ribbons. An interdigitated lamellar packing model of acidic SL-COOH molecules with a long period of 2.78 nm, stabilized by both the strong hydrophobic association between the cis-9-octadecenoic chains and strong disaccharide-disaccharide hydrogen bonding, is proposed. The neutralization of SL-COOH in water to SL-COONa produced clear solutions with the formation of short-range ordered aggregates. At concentrations below 1.0 mg/mL, the size of self-assembled aggregates increased as the concentration increased. At concentrations above 1.0 mg/mL, narrowly distributed micellar aggregates with a constant hydrodynamic radius (R(h)) of about 100 nm are formed. The large micelles show strong angular dependence with the fast mode appearing at scattering angle theta >/= 60 degrees.

Glycolipids↗
PubMed2004

Biocompatibility of sorbitol-containing polyesters. Part I: Synthesis, surface analysis and cell response in vitro.

A series of sorbitol-containing polyesters were synthesized via a one-pot lipase-catalyzed condensation polymerization. Thin films were prepared by spin coating on silicon wafers and surfaces were analyzed by tapping mode atomic force microscopy and contact angle measurements. Surface morphologies and surface energies across the series of polyester films, including a poly(epsilon-caprolactone) (PCL) control were nearly indistinguishable. Biocompatibility of the sorbitol-containing polyester series was evaluated against a PCL control by measuring cell spreading and proliferation of a mouse fibroblast 3T3 cell line in vitro. Results confirmed that the sorbitol-containing polyester surfaces elicited cell behavior similar to the PCL control. These results establish the sorbitol-containing polyester series as a promising material for tissue engineering research and development.

3T3 Cells↗
PubMed2002

Understanding medical error and improving patient safety in the inpatient setting.

Improving patient safety incorporates two complementary approaches. The first, inspired by research in cognitive psychology and the lessons of accident investigation in other industries, provides qualitative methods for anticipating errors, documenting critical incidents, and responding to them in a blame-free and structured manner. Using such qualitative methods, physicians can generate meaningful strategies for preventing similar occurrences in the future. Hospital-based physicians have an important role to play in promoting a culture of safety by championing incident-reporting initiatives and participating in multidisciplinary teams that analyze adverse events and promote change. The second approach involves applying the results of quantitative clinical research to reduce some of the common hazards of hospitalization. Hospitalists also have an important role to play in this arena because many of these safety targets and the associated clinical practices (e.g., early enteral nutritional support and fall prevention) are not on the radar screens of many hospital-based specialists. In both circumstances, physician participation in collaboration with nurses, pharmacists, nutritionists, and other health care professionals would likely produce important improvements in patient care. More important, physician involvement in these initiatives will undoubtedly contribute visible leadership in promoting a culture of patient safety in hospitals and in health care.

Hospital Administration↗
PubMedDate not supplied

Amino acid conjugated sophorolipids: A new family of biologically active functionalized glycolipids.

Sophorolipids (SLs) are extra cellular glycolipids produced by Candida bombicola ATCC 22214 when grown in the presence of glucose and fatty acids. These compounds have a disaccharide head group connected to a long-chain hydroxyl-fatty acid by a glycosidic bond. To explore structure-activity of modified SLs, a new family of amino acid-SL derivatives was prepared. Synthesized analogs consist of amino acids linked by amide bonds formed between their alpha-amino moiety and the carboxyl group of ring-opened SL fatty acids. Their preparation involved the following: (i) hydrolysis of a natural SL mixture with aqueous alkali to give SL free acids, (ii) coupling of free acids to protected amino acids using dicarbodiimide, and (iii) removing amino acid carboxyl protecting groups. These conjugates were evaluated for their antibacterial, anti-HIV, and spermicidal activity. All tested analogs showed antibacterial activity against both gram +ve and gram -ve organisms. Leucine-conjugated SL was most efficient. For example, the minimum inhibitory concentrations (MIC) for Moraxella sp. and E. coli were 0.83 and 1.67 mg/mL, respectively. Among the alkyl esters of amino acid conjugated SLs, the ethyl ester of leucine-SLs was most active. Against Moraxella sp., S. sanguinis, and M. imperiale, MIC values are 7.62 x 10(-4), 2.28 x 10-(3) and 1.67 mg/mL, respectively. All compounds displayed virus-inactivating activity with 50% effective concentrations (EC50) below 200 microg/mL. The EC50 of leucine-SL ethyl ester was 24.1 microg/mL, showing that it is more potent than commercial spermicide nonoxynol-9 (EC50 approximately 65 microg/mL).

Amino Acids↗