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Biomedical subjects

J Lowell

Publications and source records attributed to J Lowell.

18 recordsLinked to original sources
PubMed2006

Altruistic living donors: evaluation for nondirected kidney or liver donation.

A program was established within our regional procurement organization to permit evaluation of altruistic living donors (LD) interested in nondirected kidney or liver segment donation prior to transplant center referral. During the initial 30 months of program operations, 731 donor inquiries were received of which 131 individuals called back after review of mailed information materials. Forty-seven candidates initiated and 19 completed the evaluation process. Seven underwent donation to include six kidneys and one liver segment, five are actively pending donation, five were excluded from donation following transplant center evaluation and two took no further action after their intended liver recipients received deceased donor (DD) transplants. Psychological evaluation of these 19 candidates found them to be free of psychopathology, highly cooperative and self-directed. They did not exhibit attention-seeking or religious motivations for their actions. All seven donors and recipients continue to do well postoperatively. This evaluation program has made possible large-scale screening and education of prospective altruistic LD within the general population and also provides a unique opportunity to further our understanding of those individuals interested in living-nondirected donation.

Adult↗
PubMed2001

Activation of human dendritic cells by porcine aortic endothelial cells: transactivation of naïve T cells through costimulation and cytokine generation.

BACKGROUND: Dendritic cells (DC) are the most potent antigen-presenting cells in the immune system. To define the role of human DC in human anti-porcine immune responses, we defined the interaction of human DC with porcine aortic endothelial cells (PAEC). METHODS: To determine the immune responses, both monocyte-derived and peripheral blood DC were cultured with porcine and human endothelial cells. We analyzed the role of CD11a, CD11b, and CD54 in a cell-to-cell adhesion assay using antibodies against these molecules. The expression pattern of costimulatory molecules (CD40, CD80, CD86), adhesion molecules (CD54), and intracellular cytokines (interleukin-12p70 and tumor necrosis factor [TNF]-alpha) in DC after interaction with endothelial cells was determined by immunofluorescence. RESULTS: Human DC significantly adhered to PAEC (38-40%), and this adhesion was augmented (>50%) upon treatment with either recombinant swine interferon-gamma or recombinant human TNF-alpha. Addition of human DC to PAEC was blocked by pretreatment of DC with antibodies specific to human leukocyte function-associated antigen-1 or CD54. Adhesion of DC to PAEC also resulted in the activation of DC, which was manifested by up-regulation of costimulatory molecules (CD40, CD80, CD86), adhesion molecules (CD54), and HLA-DR. PAEC-activated human DC provided proliferative signals to the naïve autologous CD4+ T cells and synthesized interleukin-12p70 and TNF-alpha. However, activated DCs failed to lyse PAEC in such interaction. CONCLUSION: Human DC effectively adhered to PAEC and were activated by xenoantigen, resulting in highly efficient antigen presentation and proliferation of CD4+ T cells. Further, this interaction of human DC to PAEC is regulated by the participation of costimulatory and adherence molecules and cytokines.

Animals↗
PubMed2000

Palliative care.

Explore the source record for details and available documents.

Caregivers↗
PubMed2000

Contraceptive requirements for clinical research.

OBJECTIVE: To survey the type and frequency of use of contraceptive requirements for entry into clinical trials. METHODS: We reviewed 410 protocols submitted between January 1994 and January 1997 to one Institutional Review Board. RESULTS: Contraception or sterility for women was required in 171 (41.7%) protocols without explanation and 146 (35.6%) based on study drug. Eight and one half percent hd no exclusions. Signature certification of contraceptive use was required in 138 protocols; 230 required certification of understanding requirements; and 101 required two signatures. Signature certification documenting no pregnancy at enrollment was required in 234 protocols. There were no requirements for signatures from male subjects. Celibacy or sexual orientation were not recognized as reasons for waiver from signature requirements. CONCLUSION: The broad application of contraceptive requirements potentially creates disproportionate burdens and access by gender to participation in clinical research. Careful elucidation of methods, timing, and the consent process in order to avoid potential fetal risk and encourage inclusion of hormonally intact women will improve research and access.

Clinical Protocols↗
PubMed1997

Use of small and large bowel in renal transplantation.

The continued success of renal transplantation has provided a higher quality of life for properly selected patients with ESRD. It is also a much more cost-effective and efficient treatment of ESRD compared with chronic dialysis. Innovative urologic reconstructive surgery using enteric segments for both continent and incontinent urinary diversions has permitted this therapeutic modality to be offered to the recipient with lower urinary tract disease not previously amenable to renal transplantation. These same reconstructive techniques using ileal segments have also permitted preservation of renal allografts with previously nonreconstructable renal pelvic or ureteral disease.

Humans↗
PubMed1997

Renal allograft infiltrating lymphocytes: frequency of tissue specific lymphocytes.

Acute rejection, mediated by T lymphocytes recognizing donor MHC class I and II, is a major factor influencing renal transplant survival. To define the specificity of these effector cells we examined cytolytic activity of graft infiltrating T lymphocytes (GIL) from renal biopsies of individuals undergoing acute cellular rejection. The majority of these cells recognized MHC class I on both donor kidney epithelial cells (KCL) and B-lymphoblastoid cells (LCL) suggesting these T cells recognized peptides from various tissues. However, cold target inhibition experiments demonstrated a significant proportion of GIL T cells were tissue specific. We reported previously that kidney specific CTL can be isolated from biopsies of kidney allografts undergoing acute cellular rejection. Here we extend that observation showing we were able to isolate tissue specific CTL from two additional biopsies. Greater than 10% of the clones isolated (4 of 36 and 5 of 37) from these biopsies were CTL recognizing donor KCL but not LCL targets suggesting that peptides, recognized in the context of donor MHC, were tissue specific. Repeated isolation of significant numbers of tissue specific CTL suggests these T cells play a role in allograft rejection and may be important effector cells mediating rejection in HLA matched transplants.

Adult↗
PubMed1997

Sounds of silence.

Strategies are described for dealing with three categories of reportable occurrences: inappropriate peer behavior, including substance abuse and behavioral problems; abuse, neglect and exploitation of patients; and issues concerning treatment orders. The American Nurses Association's (ANA) Code for Nurses, individual State Departments of Nursing License Regulations and State Intervention Projects for Nurses provide some direction for identifying, reporting and resolving occurrences.

Decision Trees↗
PubMed1996

Biochemical and immunological evaluation of donor-specific soluble HLA in the circulation of liver transplant recipients.

MHC antigens, normally expressed as integral membrane proteins, are also present in soluble form in the peripheral circulation. These soluble human leukocyte antigens (sHLA) are found at elevated levels in patients with a variety of infections as well as in organ transplant recipients. In liver transplant recipients, however, most of the circulating sHLA are of donor phenotype, especially during the early posttransplant period. Here we report the purification and characterization of sHLA of both recipient and donor origin from liver transplant recipients. It was observed that sHLA consisted of four major polypeptides having molecular mass of 44, 41, 35-37, and 12 kD complexed with IgM and IgG antibodies. Further analysis revealed that these immunoglobulins contained anti-HLA antibodies. Analysis of the affinity-purified materials by a number of approaches failed to detect any other fragment(s) of HLA class I heavy chain polypeptides smaller than 12 kD. No significant difference was observed in the biochemical nature of the sHLA of donor and recipient origin and they were similar to those found in normal individuals. Affinity-purified HLA-A3 inhibited the cytolytic activity of an HLA-A3-specific CD8+ T cell line, whereas, purified sHLA-A2 failed to inhibit anti-HLA-A3 CTL activity. Further, the proliferation of the T cell line was not inhibited by sHLA-A3. Thus, the inhibitory activity shown by sHLA was antigen-specific and directed against a functional subset of T lymphocytes. These results support the notion that sHLA may play an important regulatory role in the immune response to allograft in humans.

Adult↗
PubMed1996

Yeast SAS silencing genes and human genes associated with AML and HIV-1 Tat interactions are homologous with acetyltransferases.

Silencing is an epigenetic form of transcriptional regulation whereby genes are heritably, but not necessarily permanently, inactivated. We have identified the Saccharomyces cerevisiae genes SAS2 and SAS3 through a screen for enhancers of sir1 epigenetic silencing defects. SAS2, SAS3 and a Schizosaccharomyces pombe homologue are closely related to several human genes, including one associated with acute myeloid leukaemia arising from the recurrent translocation t(8;16)(p11;p13) and one implicated in HIV-1 Tat interactions. All of these genes encode proteins with an atypical zinc finger and well-conserved similarities to acetyltransferases. Sequence similarities and yeast mutant phenotypes suggest that SAS-like genes function in transcriptional regulation and cell-cycle exit and reveal novel connections between transcriptional silencing and human disease.

Acetyltransferases↗
PubMed1979

Continuous oculoplethysmographic monitoring during carotid endarterectomy.

Oculoplethysmography has moved from the noninvasive vascular diagnostic laboratory to the operating room and is serving a new role in monitoring internal carotid shunt blood flow during carotid endarterectomy. Temporary intraoperative shunt occlusions are instantly indicated by accurate ocular pulse delay information digitally displayed to the surgeon. Corrections in shunt placement may be made promptly and, therefore, adequate internal carotid blood flow maintained, allowing "safe" time for careful endarterectomy or vascular reconstruction. Verification of satisfactory flow after arteriorhaphy is obtained by oculoplethysmography.

Carotid Artery Thrombosis↗