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Biomedical subjects

S B Jones

Publications and source records attributed to S B Jones.

At least 19 recordsLinked to original sources
PubMed2002

Glutamate-induced delta-catenin redistribution and dissociation from postsynaptic receptor complexes.

Delta-catenin (or neural plakophilin-related arm-repeat protein/neurojungin) is primarily a brain specific member of the p120(ctn) subfamily of armadillo/beta-catenin proteins that play important roles in neuronal development. Our previous studies have shown that the ectopic expression of delta-catenin induces the formation of dendrite-like extensions and that the overexpression of delta-catenin promotes dendritic branching and increases spine density. Here we demonstrate that delta-catenin displays a dendritic distribution pattern in the adult mouse brain and is co-enriched with postsynaptic density-95 (PSD-95) in the detergent insoluble postsynaptic scaffolds. Delta-catenin forms stable complexes with excitatory neurotransmitter receptors including ionotropic N-methyl-D-aspartic acid receptor 2A (NR2A), metabotropic glutamate receptor 1alpha (mGluR1alpha), as well as PSD-95 in vivo. In cultured primary embryonic neurons, delta-catenin clusters co-distribute with filamentous actin and resist detergent extraction. In dissociated hippocampal neurons overexpressing delta-catenin, glutamate stimulation leads to a rapid redistribution of delta-catenin that can be attenuated by 6-cyano-7-nitroquinoxaline-2,3-dione and dizocilpine, selective inhibitors of ionotropic glutamate receptors. Upon glutamate receptor activation, delta-catenin becomes down-regulated and its association with NR2A and mGluR1alpha in cultured neurons is diminished. These findings support a possible functional connection between delta-catenin and the glutamatergic excitatory synaptic signaling pathway during neuronal development.

Actin Cytoskeleton↗
PubMed2001

Cholinergic and behavioral neurotoxicity of carbaryl and cadmium to larval rainbow trout (Oncorhynchus mykiss).

Pesticides and heavy metals are common environmental contaminants that can cause neurotoxicity to aquatic organisms, impairing reproduction and survival. Neurotoxic effects of cadmium and carbaryl exposures were estimated in larval rainbow trout (RBT; Oncorhynchus mykiss) using changes in physiological endpoints and correlations with behavioral responses. Following exposures, RBT were videotaped to assess swimming speed. Brain tissue was used to measure cholinesterase (ChE) activity, muscarinic cholinergic receptor (MChR) number, and MChR affinity. ChE activity decreased with increasing concentrations of carbaryl but not of cadmium. MChR were not affected by exposure to either carbaryl or cadmium. Swimming speed correlated with ChE activity in carbaryl-exposed RBT, but no correlation occurred in cadmium-exposed fish. Thus, carbaryl exposure resulted in neurotoxicity reflected by changes in physiological and behavioral parameters measured, while cadmium exposure did not. Correlations between behavior and physiology provide a useful assessment of neurotoxicity.

Animals↗
PubMed2001

Behavioral dysfunctions correlate to altered physiology in rainbow trout (Oncorynchus mykiss) exposed to cholinesterase-inhibiting chemicals.

We selected four metrics of swimming behavior (distance swam, speed, rate of turning, and tortuosity of path) and the commonly used biochemical marker, brain cholinesterase (ChE) activity, to assess (1) the sensitivity and reliability of behavior as a potential biomarker in monitoring work, (2) the potential for these endpoints to be used in automated monitoring, and (3) the linkage between behavior and its underlying biochemistry. Malathion-exposed fish exhibited large decreases in distance and speed and swam in a more linear path than control fish after 24 h exposure. By 96 h exposure, fish still swam slower and traveled less distance; fish fully recovered after 48 h in clean water. Diazinon-exposed fish exhibited decreases in distance, speed, and turning rate compared to controls. After 48 h recovery in clean water, fish exposed to diazinon had not recovered to control levels. The behavioral responses provided measures of neurotoxicity that were easily quantifiable by automated means, implying that the inclusion of behavior in monitoring programs can be successful. Furthermore, correlations between behavior and biochemical endpoints, such as ChE inhibition, suggest that this approach can provide a meaningful link between biochemistry and behavior and can provide useful information on toxicant impacts.

Animals↗
PubMed2001

Surgical aspects and future developments of laparoscopy.

Laparoscopy has revolutionized surgery and in the process influenced the practice of anesthesiology. This article reviews several minimal access procedures that have been accepted into practice, are gaining acceptance, or remain investigational. Absolute contraindications to laparoscopy have been emphasized. As the threshold for primary care physicians to refer sicker and sicker patients for surgery decreases, it is crucial for the anesthesiologist to understand physiologic stresses of pneumoperitoneum and the nuances of laparoscopic surgery. The anesthesiologist also can be recruited to adjust insufflation pressures, tweak images on monitors, rotate and position the patient, or pass balloons and bougies. With patient and surgeon expectation of no pain or nausea and early discharge, anesthetic choices become vital for the ultimate success of the procedure.

Adrenalectomy↗
PubMed2001

Norepinephrine modulates myelopoiesis after experimental thermal injury with sepsis.

OBJECTIVE: To determine whether thermal injury and sepsis cause an increase in bone marrow norepinephrine release and whether such a release influences bone marrow monocytopoiesis. SUMMARY BACKGROUND DATA: The authors previously demonstrated enhanced bone marrow monocytopoiesis after burn with sepsis. They also showed that physiologic stress and bacterial challenge without injury could lead to a dynamic release of norepinephrine from the bone marrow compartment. In this study, they sought to determine the potential cause-and-effect relationship of bone marrow norepinephrine release on increased monocytopoiesis after burn sepsis. METHODS: Norepinephrine release from bone marrow was determined by traditional pulse-chase methods. Tissue and bone marrow norepinephrine content was ablated by chemical sympathectomy with 6-hydroxydopamine treatment. Clonogenic potential in response to colony-stimulating factors was determined in total nucleated bone marrow cells. Dual color flow cytometry was used to document the distribution pattern of monocyte progenitors. RESULTS: Burn sepsis induced increased norepinephrine release in bone marrow, spleen, and heart. Colony-forming assays demonstrated an increase in responsive colonies, which was significantly attenuated when norepinephrine content was reduced in animals before burn sepsis. Flow cytometric analysis of early and late monocyte progenitors showed a significantly altered distribution profile of monocyte progenitors in norepinephrine-depleted mice compared with norepinephrine-intact mice. Abrogation of bone marrow norepinephrine content resulted in a 62% survival rate in burn septic mice compared with no survivors in norepinephrine-intact mice. CONCLUSIONS: These data suggest that enhanced bone marrow norepinephrine release after burn sepsis may play a role in bone marrow monocytopoiesis, thus contributing to the sustenance of inflammation.

Animals↗
PubMed2000

Preparing surgeons for the 21st century. Implications of advanced technologies.

An entire spectrum of advanced technologies and concepts has been presented, from the new clinical applications to highly speculative possibilities. Not all of these technologies will survive the long process to clinical usefulness, but those that do may revolutionize surgery. With such change comes the ethical and moral responsibility to consider them not only in the light of improvement of patient care but also in their impact on society as a whole. If the remarkable rate of change of the past 2 decades continues, it is impossible to conceive of the role of future surgeons. Thus, to be prepared, surgeons must have an open mind, a willingness to consider and evaluate new directions, and the honesty and courage to change when a new approach is proven to be of value. A prepared mind is an open mind.

Colonoscopy↗
PubMed2000

An approach for assessment of water quality using semipermeable membrane devices (SPMDs) and bioindicator tests.

As an integral part of our continued development of water quality assessment approaches, we combined integrative sampling, instrumental analysis of widely occurring anthropogenic contaminants, and the application of a suite of bioindicator tests as a specific part of a broader survey of ecological conditions, species diversity, and habitat quality in the Santa Cruz River in Arizona, USA. Lipid-containing semipermeable membrane devices (SPMDs) were employed to sequester waterborne hydrophobic chemicals. Instrumental analysis and a suite of bioindicator tests were used to determine the presence and potential toxicological relevance of mixtures of bioavailable chemicals in two major water sources of the Santa Cruz River. The SPMDs were deployed at two sites; the effluent weir of the International Wastewater Treatment Plant (IWWTP) and the Nogales Wash. Both of these systems empty into the Santa Cruz River and the IWWTP effluent is a potential source of water for a constructed wetland complex. Analysis of the SPMD sample extracts revealed the presence of organochlorine pesticides (OCs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). The bioindicator tests demonstrated increased liver enzyme activity, perturbation of neurotransmitter systems and potential endocrine disrupting effects (vitellogenin induction) in fish exposed to the extracts. With increasing global demands on limited water resources, the approach described herein provides an assessment paradigm applicable to determining the quality of water in a broad range of aquatic systems.

Animals↗
PubMed2000

Microgravity effects on water supply and substrate properties in porous matrix root support systems.

The control of water content and water movement in granular substrate-based plant root systems in microgravity is a complex problem. Improper water and oxygen delivery to plant roots has delayed studies of the effects of microgravity on plant development and the use of plants in physical and mental life support systems. Our international effort (USA, Russia and Bulgaria) has upgraded the plant growth facilities on the Mir Orbital Station (OS) and used them to study the full life cycle of plants. The Bulgarian-Russian-developed Svet Space Greenhouse (SG) system was upgraded on the Mir OS in 1996. The US developed Gas Exchange Measurement System (GEMS) greatly extends the range of environmental parameters monitored. The Svet-GEMS complex was used to grow a fully developed wheat crop during 1996. The growth rate and development of these plants compared well with earth grown plants indicating that the root zone water and oxygen stresses that have limited plant development in previous long-duration experiments have been overcome. However, management of the root environment during this experiment involved several significant changes in control settings as the relationship between the water delivery system, water status sensors, and the substrate changed during the growth cycles.

Carbon Dioxide↗
PubMed2000

Controversies in sentinel lymph node biopsy for breast cancer.

Sentinel lymph node biopsy, validated in melanoma staging, is currently under investigation for breast cancer staging. Reports suggest that the sentinel lymph node has a high predictive value in determining the presence of axillary metastases. Identification of a sentinel lymph node that is free of metastatic tumor cells may eliminate the necessity of performing a standard axillary lymph node dissection with its attendant morbidity. Numerous techniques are utilized to identify the sentinel node with approximately the same success rate. This paper will address some of the controversial areas of sentinel lymph node biopsy and offer an option for physicians who want to develop a sentinel lymph node program in their hospital.

Breast Neoplasms↗
PubMed1999

Microgravity effects on water flow and distribution in unsaturated porous media: analyses of flight experiments.

Plants grown in porous media are part of a bioregenerative life support system designed for long-duration space missions. Reduced gravity conditions of orbiting spacecraft (microgravity) alter several aspects of liquid flow and distribution within partially saturated porous media. The objectives of this study were to evaluate the suitability of conventional capillary flow theory in simulating water distribution in porous media measured in a microgravity environment. Data from experiments aboard the Russian space station Mir and a U.S. space shuttle were simulated by elimination of the gravitational term from the Richards equation. Qualitative comparisons with media hydraulic parameters measured on Earth suggest narrower pore size distributions and inactive or nonparticipating large pores in microgravity. Evidence of accentuated hysteresis, altered soil-water characteristic, and reduced unsaturated hydraulic conductivity from microgravity simulations may be attributable to a number of proposed secondary mechanisms. These are likely spawned by enhanced and modified paths of interfacial flows and an altered force ratio of capillary to body forces in microgravity.

Capillary Action↗
PubMed1999

Bacterial vaginosis, ethnicity, and the use of genital cleaning agents: a case control study.

BACKGROUND AND OBJECTIVES: Bacterial vaginosis and vaginal douching are both reported to be more common in African-American and Caribbean than white women. It is also thought that douching alters the vaginal milieu. This study was conducted to examine associations between genital cleaning practices, bacterial vaginosis, and ethnic group. STUDY DESIGN: Case-control study of 100 women with bacterial vaginosis, diagnosed by Nugent's criteria, and 100 women without bacterial vaginosis attending a sexually transmitted diseases clinic in an ethnically heterogeneous inner-city area in London, England. RESULTS: Bacterial vaginosis was more common among black Caribbean than white women (OR, 2.1; 95% CI, 1.1-4.1). Vulval use of bubble bath or antiseptic solutions and douching with proprietary or homemade solutions were significantly more common in women with bacterial vaginosis than without. After controlling for use of vulval and vaginal antiseptics and bubble bath, douching, and a history of bacterial vaginosis, there was no ethnic difference in the occurrence of the condition (adjusted OR, 1.1; 95% CI, 0.5-2.5). CONCLUSIONS: Ethnic differences in genital hygiene behaviors can explain a twofold increase in the risk of bacterial vaginosis in black Caribbean compared with white women. The role of vulval and vaginal cleaning practices in the development of bacterial vaginosis should be examined further in longitudinal or randomized controlled studies.

Adult↗
PubMed1999

Factors associated with occupational exposure and compliance with universal precautions in an urban school district.

Factors associated with occupational exposure and universal precautions (UP) compliance were assessed among employees in one urban school district. Half of the employees surveyed reported responding to bleeding injuries and cleaning blood or other body fluids (e.g., vomit, urine) during the previous school year. Also, 1 in 4 custodians and 1 in 10 teachers/teacher's aides had direct contact with blood or body fluids without protection. In multivariate logistic regression analyses, direct contact was most likely among secondary school employees in unpredictable situations who did not have protective equipment or comply with UP. UP compliance was greater among those who had protective equipment available and felt self-confident. Self-confidence was associated with having received training or protective equipment. Routine communications between administrators and employees, staff training, provision of protective equipment, and exposure incident monitoring are essential to effective implementation of UP policies in schools and work settings where occupational exposure could occur.

Analysis of Variance↗
PubMed1998

Otolaryngology in the information age: enabling technologies for the future of surgery. Enabling technologies for the future of surgery.

Enabling technologies for the future, whether exemplified by endoscopic, minimally invasive, or microdexterity systems or surgical and nonsurgical image-guided procedures, continue with an evolution so rapid that before one change has been accepted and perfected, another even more dramatic change promises to replace it. These information-based surgical and procedural interventions are just now becoming accepted standards of surgical, radiologic, and medical practice, and yet the promise of more advanced technologies blurs even these new boundaries, constantly redefining the concept of "surgery." It is essential that otolaryngologists, as part of the broader spectrum of physicians, understand these changes and prepare to adapt and improve each and every one of their technical and cognitive skills.

Computer Simulation↗
PubMed1998

Laparoscopic surgery. Transition to the future.

The twenty-first century will usher in a fundamentally new approach to the practice of medicine. It will be based heavily on information technologies, broadly defined as the devices that acquire information; those that process, transmit, and distribute information; and those that use information to provide therapy. Although conventional surgery will continue to have a presence, there will be radically different surgical approaches and technologies that may become the predominant form of surgery. The medical record may become a three-dimensional visual representation of the individual patient (like the Visible Human Project), which can be the vehicle that integrates the entire spectrum of health care. Examples of the technologies and infrastructures that support this new approach to medicine are discussed and illustrated, with emphasis on how technologies improve individual patient care.

Forecasting↗
PubMed1998

A capillary-driven root module for plant growth in microgravity.

A new capillary-driven root module design for growing plants in microgravity was developed which requires minimal external control. Unlike existing systems, the water supply to the capillary-driven system is passive and relies on root uptake and media properties to develop driving gradients which operate a suction-induced flow control valve. A collapsible reservoir supplies water to the porous membrane which functions to maintain hydraulic continuity. Sheet and tubular membranes consisting of nylon, polyester and sintered porous stainless steel were tested. While finer pore sized membranes allow greater range of operation, they also reduce liquid flux thereby constraining system efficiency. Membrane selection should consider both the maximum anticipated liquid uptake rate and maximum operating matric head (suction) of the system. Matching growth media water retention characteristics to the porous membrane characteristics is essential for supplying adequate liquid flux and gas exchange. A minimum of 10% air-filled porosity (AFP) was necessary for adequate aeration. The capillary-driven module maintained hydraulic continuity and proper gas exchange rates for more than 80 days in a plant growth experiment.

Capillary Action↗
PubMed1998

Particulated growth media for optimal liquid and gaseous fluxes to plant roots in microgravity.

An important and yet relatively under researched area of plant growth in microgravity, deals with the rooting environment of plants. A comprehensive approach for selecting the physical characteristics of root growth media which optimizes the dynamic availability of water and dissolved nutrients, and gases to plant roots was developed and tested. Physically-based and parametric models describing the relationship between content and fluxes of liquids and gases were used to cast a multi-objective optimization problem. This methodology reveals that a medium's ability to supply liquid and gas fluxes optimally is dependent upon physiological target values, system operation limits and root module design which dictate the medium's range of soil water characteristic and particle size distribution. Optimized media parameters designate a particle size distribution from which a particulated growth media was constructed and matched to the optimized media parameters. This methodology should improve the selection of optimal media properties for plant growth in microgravity as well as other porous media applications.

Culture Media↗
PubMed1998

Effects of carbaryl, permethrin, 4-nonylphenol, and copper on muscarinic cholinergic receptors in brain of surrogate and listed fish species.

We investigated the regulation of the muscarinic cholinergic receptor (MChR) in brain from seven species of fish, two surrogates and five threatened or endangered species exposed to a series of chemicals as a measure of compensatory response among species. Fish were classified as either cold water (rainbow trout-surrogate, apache trout, lahanton trout) or warm water (fathead minnow-surrogate, razorback sucker, bonytail chub, colorado squawfish) and were exposed to chemicals shown to affect cholinergic pathways (carbaryl and permethrin) and two chemicals whose relationships to the cholinergic system is less clear (4-nonylphenol and copper). Downregulation of MChR occurred in all warm water species, except colorado squawfish, and at carbaryl concentrations similar to those causing downregulation observed in rainbow trout. Permethrin exposure resulted in downregulation in fathead minnow and razorback sucker, but the concentrations required for observation of this phenomenon were much greater than observed in cold water species. Copper exposure caused a decrease in brain MChR in rainbow trout and apache trout, whereas 4-nonylphenol exposure resulted in a decrease in brain MChR in all three cold water species. Our results indicate that surrogates are useful in assessing sublethal physiological responses to chemicals with a known mechanism of action such as carbaryl and support use of surrogates for assessing physiological responses to chemicals with diverse, less clear mechanisms of action.

Animals↗