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Biomedical subjects

P Gardner

Publications and source records attributed to P Gardner.

At least 19 recordsLinked to original sources
PubMed2005

Fixation protocols for subcellular imaging by synchrotron-based Fourier transform infrared microspectroscopy.

Synchrotron-based Fourier transform infrared (SR-FTIR) microspectroscopy is a powerful bioanalytical technique for the simultaneous analysis of lipids, proteins, carbohydrates, and a variety of phosphorylated molecules within intact cells. SR-FTIR microspectroscopy can be used in the imaging mode to generate biospectroscopic maps of the distribution and intensity profiles of subcellular biomolecular domains at diffraction-limited spatial resolution. However, the acquisition of highly spatially resolved IR images of cells is not only a function of instrumental parameters (source brightness, sampling aperture size) but also the cell preparation method employed. Additionally, for the IR data to be biochemically relevant the cells must be preserved in a life-like state without introducing artefacts. In the present study we demonstrate, for the first time, the differences in biomolecular localizations observed in SR-FTIR images of cells fixed by formalin, formalin-critical point drying (CPD), and glutaraldehyde-osmium tetroxide-CPD, using the PC-3 prostate cancer cell line. We compare these SR-FTIR images of fixed cells to unfixed cells. The influence of chemical fixatives on the IR spectrum is discussed in addition to the biological significance of the observed localizations. Our experiments reveal that formalin fixation at low concentration preserves lipid, phosphate, and protein components without significantly influencing the IR spectrum of the cell.

Animals↗
PubMed2003

Applications of Fourier transform infrared microspectroscopy in studies of benign prostate and prostate cancer. A pilot study.

Fourier transform infrared (FTIR) microspectroscopy has been applied to a study of prostate cancer cell lines derived from different metastatic sites and to tissue from benign prostate and Gleason-graded malignant prostate tissue. Paraffin-embedded tissue samples were analysed by FTIR, after mounting onto a BaF(2) plate and subsequent removal of wax using Citroclear followed by acetone. Cell lines were analysed as aliquots of cell suspension held between two BaF(2) plates. It was found that the ratio of peak areas at 1030 and 1080 cm(-1), corresponding to the glycogen and phosphate vibrations respectively, suggests a potential method for the differentiation of benign from malignant cells. The use of this ratio in association with FTIR spectral imaging provides a basis for estimating areas of malignant tissue within defined regions of a specimen. Initial chemometric treatment of FTIR spectra, using the linear discriminant algorithm, demonstrates a promising method for the classification of benign and malignant tissue and the separation of Gleason-graded CaP spectra. Using the principle component analysis, this study has achieved for the first time the separation of FTIR spectra of prostate cancer cell lines derived from different metastatic sites.

Adenocarcinoma↗
PubMed2001

Recommended schedules for routine immunization of children and adults.

Vaccine recommendations continue to evolve as a result of new vaccines, safety considerations, changing disease incidence (e.g., polio), and public health priorities. The pace of discovery is accelerating and advisory committees will need to respond accordingly. Each vaccine, new or old, will be required to earn its place in the routine immunization schedule on the basis of public health benefit or cost-benefit studies.

Adult↗
PubMed2001

Standards for immunization practice for vaccines in children and adults.

Administration of vaccines is a continuing challenge. In childhood immunizations, many of the goals for national coverage rates by 2000 were achieved and the goal of annual influenza immunization for adults 65 years of age and older was reached. These successes in childhood immunization rates have led to record low numbers of cases of many vaccine-preventable diseases, such as measles and Haemophilus influenzae, type b invasive disease. These diseases will recur, however, as evidenced by the measles epidemic of 1989-1991, if high immunization coverage is not maintained. The development of immunization delivery systems to sustain these high rates in young children is essential to ensure that the 11,000 infants born each day in the United States receive all recommended vaccines, as noted in the recent NVAC report on strategies to sustain success in childhood immunization. For adults, the total economic burden of treating these vaccine-preventable diseases is estimated to exceed $10 billion each year, reflecting in part widespread underuse of vaccines in adults and resulting missed opportunities to prevent diseases such as influenza and pneumococcal infection. The development of standards for immunization practices in children and adults has been an important component in meeting these challenges and ensuring appropriate delivery of vaccines. Periodic review and updating is necessary and revision of the standards for adults by the NCAI and NVAC, pediatric standards, and those of the IDSA currently are undergoing revision. Most importantly, however, standards for immunization practices should be promulgated widely to all health care professionals to ensure that all segments of the population benefit from the availability of highly effective and safe vaccines.

Adult↗
PubMed2001

Issues related to the decennial tetanus-diphtheria toxoid booster recommendations in adults.

In terms of disease prevention, reduction of adverse reactions, and cost benefit studies, a strong case can be made for a policy that focuses on assuring high levels of primary immunization with tetanus and diphtheria (Td) toxoids and abandons the decennial Td booster in favor of a single midlife booster at age 50-65 years. The addition of acellular pertussis antigens to Td for routine use in adults has potential problems in terms of schedule, cost, and possible adverse reactions. Careful risk/benefit studies are necessary to evaluate its effectiveness and priority.

Adult↗
PubMed2000

A role for CaMKII in T cell memory.

In order to study the role of calcium/calmodulin kinase II (CaMKII) in T cells, we generated transgenic mice expressing CaMKIIgammaB* (T287D), a partially calcium-independent mutant of CaMKIIgammaB. In these mice, the size of the thymus was increased 1.5- to 2-fold, at least in part due to an increase in the lifespan of double-positive (DP) thymocytes. More importantly, there was an increase in the number of T cells in the secondary lymphoid organs that had acquired an antigen-dependent memory phenotype. These T cells were bonafide memory cells as assessed by a variety of criteria. In addition, T cells from wild-type mice acquired calcium-independent CaMKII activity after several rounds of antigen-stimulated division. We propose that CaMKII controls a distinct process of activation-induced cellular differentiation.

Animals↗
PubMed2000

Intensity of bacteraemia associated with conservative dental procedures in children.

OBJECTIVES: To explore the individual dento-gingival manipulative procedures that together lead to the placement of a restoration and to estimate the associated intensity of bacteraemia. PATIENTS AND METHODS: Healthy children receiving dental treatment under general anaesthesia provided blood samples 30 seconds after one of four dento-gingival manipulative procedures: 1. Placement of rubber dam, 2. Use of the high speed drill, 3. Use of the slow speed drill, and 4. Placement of matrix band and wedge. Blood cultures were processed to give the percentage prevalence of bacteraemia, the intensity of organisms per millilitre of blood and the identity of the organisms cultured. RESULTS: A total of 257 children were recruited to the study. The percentage positive prevalence of blood cultures was baseline--9.3%, rubber dam placement--31.4%, slow drill--12.2%, fast drill--4.3%, and matrix band and wedge--32.1%. The intensity of bacteraemia was baseline--1.2 cfu, rubber dam placement--1,962 cfu, slow drill--0.3 cfu, fast drill--1.9 cfu, matrix band and wedge--4.8 cfu. CONCLUSIONS: These data indicate that dento-gingival manipulative procedures comprising a simple dental restoration can lead to a bacteraemia comparable to that from dental extractions. It is suggested that these data may indicate the need for antibiotic prophylaxis for some aspects of conservative dentistry.

Adolescent↗
PubMed1999

Indications for acellular pertussis vaccines in adults: the case for selective, rather than universal, recommendations.

The availability of acellular pertussis vaccines, which appear to be both safe and immunogenic in adults, will require that vaccine advisory groups make recommendations regarding their use. Pertussis in adults has negligible mortality but is responsible for about one-quarter of cases of chronic cough syndrome in young adults. Parents and other infant caregivers are important transmitters of pertussis to infants, the group who have the highest morbidity and mortality. Assuming that further studies confirm the immunogenicity and safety profile of acellular pertussis vaccines in adults, recommendations can be made for its use for universal immunization of adolescents, epidemic control, and strongly considered targeted adults who give care to infants. Factors that mitigate against including acellular pertussis vaccine in the recommended decennial tetanus-diphtheria toxoids booster include the short duration of the immune response to the acellular pertussis vaccine, increased cost and reactogenicity, and the lack of vaccine delivery systems to most adults. The elderly and the infirm, who are the current focus of adult immunization programs, are unlikely candidates for pertussis immunization. Therefore, recommendations for use of acellular pertussis vaccine in adults should be selective, rather than universal.

Adult↗
PubMed1999

Safety and biological efficacy of an adeno-associated virus vector-cystic fibrosis transmembrane regulator (AAV-CFTR) in the cystic fibrosis maxillary sinus.

OBJECTIVE: The host immune response and low vector efficiency have been key impediments to effective cystic fibrosis transmembrane regulator (CFTR) gene transfer for cystic fibrosis (CF). An adeno-associated virus vector (AAV-CFTR) was used in a phase I dose-escalation study to transfer CFTR cDNA into respiratory epithelial cells of the maxillary sinus of 10 CF patients. STUDY DESIGN: A prospective, randomized, unblinded, dose-escalation, within-subjects, phase I clinical trial of AAV-CFTR was conducted. PATIENTS: Ten patients with previous bilateral maxillary antrostomies were treated. MAIN OUTCOME MEASURES: Safety, gene transfer as measured by semiquantitative polymerase chain reaction (PCR), and sinus transepithelial potential difference (TEPD) were measured. RESULTS: The highest level of gene transfer was observed in the range of 0.1-1 AAV-CFTR vector copy per cell in biopsy specimens obtained 2 weeks after treatment. When tested, persistence was observed in one patient for 41 days and in another for 10 weeks. Dose-dependent changes in TEPD responses to pharmacologic intervention were observed following treatments. Little or no inflammatory or immune responses were observed. CONCLUSION: AAV-CFTR administration to the maxillary sinus results in successful, dose-dependent gene transfer to the maxillary sinus and alterations in sinus TEPD suggestive of a functional effect, with little or no cytopathic or host immune response. Further study is warranted for AAV vectors as they may prove useful for CFTR gene transfer and other in vivo gene transfer therapies. A prospective, randomized, double-blind, placebo-controlled, within-subjects, phase II clinical trial of the effect AAV-CFTR on clinical recurrence of sinusitis will determine the clinical efficacy of AAV gene therapy for CF.

Adult↗
PubMed1999

An outcomes study of an occupational medicine intervention program for the reduction of musculoskeletal disorders and cumulative trauma disorders in the workplace.

Upper-extremity musculoskeletal pains or disorders (MSDs) account for a significant number of work-related illnesses in the US workforce. Although the concept of MSD prevention is appealing, little has been done to demonstrate the successful application and benefit of these programs. In 1995, an aircraft manufacturer established a unique risk-management program based on the individual risk assessment (CtdMAP) for new hires. The MSD intervention program was designed to prospectively evaluate each new employee for their individual risk of developing MSDs in the workplace. Before job placement, individuals at higher risk were assigned to a period of transitional work. Workers' compensation costs decreases per year were 16%, 3%, 24%, and 12%, while work hours increased by 56%. Employer-estimated savings in direct workers' compensation costs per year were $469,990, $678,337, $1,936,105, and $1,995,759.

Algorithms↗
PubMed1998

Post-translational processing of the insulin-like growth factor-2 precursor. Analysis of O-glycosylation and endoproteolysis.

Insulin-like growth factor-2 (IGF-2) is expressed in most embryonic tissues and is required for normal development during gestation. After birth IGF-2 expression is extinguished in most tissues, but the gene is often reactivated during tumorigenesis. Tumors secrete high molecular weight forms of IGF-2 that result from aberrant post-translational processing of pro-IGF-2. As a first step toward understanding how high molecular weight IGF-2 peptides might contribute to tumor progression, we have characterized the biosynthesis of IGF-2 in a human embryonic cell line. We have found that pro-IGF-2 can initially form two disulfide isomers that undergo rearrangement to a single conformation in vivo. The addition of N-acetylgalactosamine to Ser71, Thr72, Thr75, and Thr139 likely occurs in the cis- Golgi apparatus. Sialic acid addition begins in the trans- Golgi apparatus, but IGF-2 peptides must reach the trans-Golgi network for oligosaccharide maturation to be completed. Endoproteolysis occurs concomitant to or slightly after oligosaccharide maturation. Cleavage was observed only at Arg104, resulting in the secretion of IGF-2-(1-104) and free E-peptide. Proteolysis required basic residues in the P1 (Arg104) and P4 (Arg101) positions, was completely blocked by a furin inhibitor, and was enhanced by coexpression with furin, PACE4, PC6A, PC6B, and LPC. These data suggest that members of the subtilisin-related proprotein convertase family mediate processing of pro-IGF-2 at Arg104. We did not detect the IGF-2 peptides that are most abundant in normal serum, mature IGF-2, and IGF-2-(1-87), in this expression system, which indicates that novel endoproteases are responsible for generating these products.

Arginine↗
PubMed1998

Adenovirus-mediated transduction of intestinal cells in vivo.

The intestinal tract has many features that make it an attractive target for therapeutic gene transfer. In this study, replication-defective adenoviral vectors were used to explore parameters that may be important in administering gene therapy vectors to the intestine. After surgically accessing the intestine, an E1-, E3-deleted adenoviral vector encoding beta-galactosidase (beta-Gal) was directly injected into various regions of the small and large intestine of rats and rabbits. Significant transduction of the tissue was observed and histochemical staining was used to identify enterocytes as the primary targets of gene transfer. Expression of beta-Gal did not differ substantially when the virus was administered to the duodenum, ileum, or colon. When the vector was directly administered to segments of the distal ileum containing a Peyer's patch, transgene expression was approximately 10-fold higher than in segments lacking a Peyer's patch. In the Peyer's patches, a high level of expression was localized to epithelial cells, potentially M cells, overlying the lymphoid follicle domes. Transduction of these cells could have application in DNA-mediated oral vaccination. Administration of an adenoviral vector encoding a secreted alkaline phosphatase to the lumen resulted in expression and secretion of this gene product into the circulation. This finding demonstrates the potential of enterocytes to serve as heterotopic sites for the synthesis of heterologous gene products that would be secreted into the lumen of the intestinal tract or into the bloodstream.

Adenoviridae↗