PubMed Health⌕ Search

Biomedical subjects

J Mace

Publications and source records attributed to J Mace.

At least 19 recordsLinked to original sources
PubMed2006

Dynamic production of hypoxia-inducible factor-1alpha in early transplanted islets.

More than half of transplanted beta-cells undergo apoptotic cell death triggered by nonimmunological factors within a few days after transplantation. To investigate the dynamic hypoxic responses in early transplanted islets, syngeneic islets were transplanted under the kidney capsule of balb/c mice. Hypoxia-inducible factor-1alpha (HIF-1alpha) was strongly expressed at post-transplant day (POD) 1, increased on POD 3, and gradually diminished on POD 14. Insulin secretion decreased on POD 3 in association with a significant increase of HIF-1alpha-related beta-cell death, which can be suppressed by short-term hyperbaric oxygen therapy. On POD 7, apoptosis was not further activated by continually produced HIF-1alpha. In contrast, improvement of nerve growth factor and duodenal homeobox factor-1 (PDx-1) production resulted in islet graft recovery and remodeling. In addition, significant activation of vascular endothelial growth factor in islet grafts on POD 7 correlated with development of massive newly formed microvessels, whose maturation is advanced on POD 14 with gradual diminution of HIF-1alpha. We conclude that (1) transplanted islets strongly express HIF-1alpha in association with beta-cell death and decreased insulin production until adequate revascularization is established and (2) early suppression of HIF-1alpha results in less beta-cell death thereby minimizing early graft failure.

Animals↗
PubMed2005

Identification of single bacterial cells in aqueous solution using confocal laser tweezers Raman spectroscopy.

We report on a rapid method for reagentless identification and discrimination of single bacterial cells in aqueous solutions using a combination of laser tweezers and confocal Raman spectroscopy (LTRS). The optical trapping enables capturing of individual bacteria in aqueous solution in the focus of the laser beam and levitating the captured cell well off the cover plate, thus maximizing the excitation and collection of Raman scattering from the cell and minimizing the unwanted background from the cover plate and environment. Raman spectral patterns excited by a near-infrared laser beam provide intrinsic molecular information for reagentless analysis of the optically isolated bacterium. In our experiments, six species of bacteria were used to demonstrate the capability of the confocal LTRS in the identification and discrimination between the diverse bacterial species at various growth conditions. We show that synchronized bacterial cells can be well-discriminated among the six species using principal component analyses (PCA). Unsynchronized bacterial cells that are cultured at stationary phases can also be well-discriminated by the PCA, as well as by a hierarchical cluster analysis (HCA) of their Raman spectra. We also show that unsynchronized bacteria selected from random growth phases can be classified with the help of a generalized discriminant analysis (GDA). These findings demonstrate that the LTRS may find valuable applications in rapid sensing of microbial cells in diverse aqueous media.

Bacteria↗
PubMed2005

Beneficial effects of nerve growth factor on islet transplantation.

OBJECTIVE: Development of the Edmonton protocol was a pivotal contribution to clinical islet transplantation (ITx). Persistent limitations to ITx include insufficient supply and posttransplant functional failure of islets. In this study, nerve growth factor (NGF) was used to enhance both cultured and transplanted beta-cell function, thus achieving prolonged graft survival. METHODS: Fluorescence microscopy with ethidium bromide and SYTO green staining was used to evaluate balb/c mouse islet viability. Islets were syngeneically transplanted under the kidney capsule of recipients with streptozotocin-induced diabetes. Intraperitoneal glucose tolerance was used to test posttransplant function. RESULTS: Improved viability was found in murine islets cultured for 48 hours in 500 ng/mL NGF (P < .05). A submarginal islet mass (260 islet equivalents/recipient) was used for ITx. The NGF-culture resulted in prolonged islet survival (24.7 days vs 5.5 days without NFG culture, n = 6). Intravenous injection of NGF (6 mug) on the day of transplant and postoperative days (POD) 1 + 2 prolonged islet survival from 4.1 days (no treatment) to 13.2 days (n = 6). Glucose tolerance testing performed at posttransplant day 4 showed improvement at 60 and 120 minutes in recipients treated intravenously with NGF (blood glucose of 95 +/- 15 vs 210 +/- 78 and 57 +/- 6 vs 176 +/- 70 mg/dL, respectively). CONCLUSION: NGF may improve beta-cell function and result in prolonged survival of both cultured and transplanted islets.

Animals↗
PubMed1992

Who knows more?

Explore the source record for details and available documents.

Evaluation Studies as Topic↗
PubMed1989

Vocational training. My year as a guinea pig.

In the twilight of the first year of the new Vocational Training Scheme I am reflecting on my metamorphosis from a naive dental student to vocational trainee and ultimately (hopefully) to competent clinician.

Education, Dental↗
PubMed1988

Chest radiography in infant cardiac allotransplantation.

Heart transplants were performed in seven infants at Loma Linda University Medical Center from 1985 to 1987. Five of these seven patients survived. In this report, the radiographic appearance of the chest is presented before surgery, immediately after surgery, and during a documented episode of rejection. The most current available chest radiograph is also presented. Acute rejection was confirmed by clinical, echocardiographic, and ECG findings. The only pulmonary infection encountered was mycoplasma pneumonitis. Four patients developed gastrointestinal rotavirus infections and were shown to have dilated proximal small-bowel folds on upper gastrointestinal studies. At the time of this writing, the prognosis for the five surviving infants is good. We conclude that the radiographs of infants who have received heart transplants show an unusual cardiac contour and slight cardiomegaly. Increasing cardiomegaly can alert one to early rejection. Prominent folds in the small bowel are of uncertain origin and significance, but they may be related to infection resulting from immunosuppression.

Female↗
PubMed1987

Environmental exposure of primary care personnel to ribavirin aerosol when supervising treatment of infants with respiratory syncytial virus infections.

The potential exposure to ribavirin aerosol in the environment was assessed in nurses caring for infants and children with severe lower respiratory tract infections due to respiratory syncytial virus. Ribavirin aerosol was administered via a ventilator, oxygen tent, or oxygen hood. Participants worked directly with infants receiving ribavirin for 20.0 to 35.0 h over a 3-day period. No toxic or adverse effects of ribavirin aerosol were observed in any of the 19 nurses studied, and ribavirin was not detected in erythrocytes, plasma, or urine collected after the potential exposure period.

Adult↗
PubMed1986

Prevalence and specificity of the enhancing effect of three types of interleukin 2 on T cell responsiveness in 97 lepromatous leprosy patients of mixed ethnic origin.

Peripheral blood mononuclear cells from 97 predominantly lepromatous leprosy patients and 11 control subjects were tested in a lymphoproliferative assay for response to Mycobacterium leprae (whole and sonicated), and sonicated M. vaccae, M. tuberculosis, and M. scrofulaceum, in the presence and absence of three types of interleukin 2 (IL-2) (crude, purified, and recombinant). IL-2 enhanced the response to sonicated M. tuberculosis and M. leprae organisms more often in patients than in control subjects, but not significantly so and only in a minority of patients. This effect was significantly more common (though still only found in a minority of 46%) using M. leprae organisms as antigen, than when using sonicates of M. leprae (19%) or M. vaccae (19%). However it was nearly as frequent using sonicated M. tuberculosis, or M. scrofulaceum. Thus in only nine patients was the effect specific to M. leprae. Enhancement by IL-2 could not be related to the type of IL-2 used, the dose of antigen, or the amount of endogenous IL-2 released by the cells tested. Similarly it was not related to the extent to which IL-2 caused increased background proliferation in control wells, which occurred to an equal extent using cells from control subjects, nor was it related to the extent of antigen-driven proliferation. The data have also been analysed in relation to duration of disease (50 years to a few weeks) and ethnic origin. No correlations have been revealed. Thus enhancement by IL-2 of the lymphoproliferative response to mycobacterial antigens does occur using cells from lepromatous leprosy patients, but it is found in a minority of patients, it is not specific to M. leprae, and can occur with cells from normal donors.

Antigens, Bacterial↗
PubMed1986

Responsiveness to live M. tuberculosis, and common antigens, of sonicate-stimulated T cell lines from normal donors.

Live mycobacteria are more efficient vaccines against mycobacterial disease than killed ones. A possible explanation is the existence of important protective antigens released by live bacilli, which are not present in any significant quantity in dead ones. Conversely, internal mycobacterial antigens may be irrelevant to protection if not released by live bacilli. We show here, using T cell lines derived by limiting dilution from the peripheral blood of normal donors stimulated with sonicated BCG, that a variable percentage of sonicate responsive T cells is unable to respond to live M. tuberculosis. The possibility that such lines have an immunopathological, rather than protective role, is discussed.

Antigens, Bacterial↗