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Biomedical subjects

L Mills

Publications and source records attributed to L Mills.

At least 37 records · Page 2Linked to original sources
PubMed1997

Immunolocalization of the Na(+)-Ca2+ exchanger in mammalian myelinated axons.

Previous studies on the pathophysiology of white matter anoxic injury have revealed that the Na(+)-Ca2+ exchanger is an important mediator of Ca2+ overload. To date, however, the localization of this key Ca2+ transporter in myelinated axons has not been demonstrated. The present study uses immunofluorescence labeling with a monoclonal antibody (R3F1) to the canine cardiac type I Na(+)-Ca2+ exchanger to localize exchanger protein to rat peripheral and central myelinated axons. The indirect immunofluorescence labeling technique was used to study paraformaldehyde fixed frozen cryostat sections of sciatic nerve, optic nerve and spinal cord. Examination of sciatic nerve sections with both conventional and confocal microscopy revealed a staining pattern which suggested both a glial and axonal localization of the exchanger. In the rat optic nerve, positive label was associated with cell bodies and their processes, likely glia, and with numerous finer processes arranged in parallel, running longitudinally. These finer processes likely represent axonal profiles. A similar staining pattern was observed in lateral and dorsal columns from spinal cord. Immunoelectron microscopy of dorsal root axons revealed gold particles associated with the paranodal and internodal myelin, in the axoplasm, and close to the nodal/paranodal axon membrane. The high density of Na(+)-Ca2+ exchanger demonstrated in central and peripheral myelinated mammalian axons supports the importance of this transporter in Ca2+ regulation in these tissues.

Animals↗
PubMed1997

Hepoxilin-evoked intracellular reorganization of calcium in human neutrophils: a confocal microscopy study.

Hepoxilin A3 has previously been shown to cause a rapid dose-dependent rise in intracellular calcium in intact human neutrophils in suspension. Two components have been observed, an initial rapid phase of intracellular calcium rise, followed by a slow decline to plateau levels that remain above the original baseline calcium levels. These changes have been suggested to involve the release of calcium from intracellular stores in the ER (initial rapid phase), while the slower rate of decline (plateau phase) was presumed to be due to calcium influx as it was abolished in zero calcium extracellular medium. The present study used confocal microscopy to examine the response to hepoxilin A3 at the subcellular level. Our results show that calcium dynamics in response to hepoxilin A3 varies in different subcellular compartments within the cell and that hepoxilin A3 evoked a persistent accumulation of calcium in organelles. The hepoxilin-evoked calcium sequestration was eliminated by prior exposure to CCCP, a mitochondrial uncoupler. CCCP also eliminated the plateau phase of the calcium response in cell suspension, suggesting that this phase was due to mitochondrial accumulation of calcium rather than calcium influx. Experiments with DiI-loaded cells, a membrane marker, showed that the nuclear calcium was not elevated by hepoxilin addition to the cells. These results demonstrate that hepoxilins evoke the release of calcium from the ER which is taken up by the mitochondria where it is tightly sequestered. These results offer an explanation of observations previously made with cell suspensions in which hepoxilin A3 was shown to inhibit the calcium mobilizing effects of chemotactic agents.

8,11,14-Eicosatrienoic Acid↗
PubMed1997

The signal response of IkappaB alpha is regulated by transferable N- and C-terminal domains.

IkappaB alpha retains the transcription factor NF-kappaB in the cytoplasm, thus inhibiting its function. Various stimuli inactivate IkappaB alpha by triggering phosphorylation of the N-terminal residues Ser32 and Ser36. Phosphorylation of both serines is demonstrated directly by phosphopeptide mapping utilizing calpain protease, which cuts approximately 60 residues from the N terminus, and by analysis of mutants lacking one or both serine residues. Phosphorylation is followed by rapid proteolysis, and the liberated NF-kappaB translocates to the nucleus, where it activates transcription of its target genes. Transfer of the N-terminal domain of IkappaB alpha to the ankyrin domain of the related oncoprotein Bcl-3 or to the unrelated protein glutathione S-transferase confers signal-induced phosphorylation on the resulting chimeric proteins. If the C-terminal domain of IkappaB alpha is transferred as well, the resulting chimeras exhibit both signal-induced phosphorylation and rapid proteolysis. Thus, the signal response of IkappaB alpha is controlled by transferable N-terminal and C-terminal domains.

Amino Acid Sequence↗
PubMed1997

A critical appraisal of the role of auditory brain stem response and magnetic resonance imaging in acoustic neuroma diagnosis.

Auditory brain stem response (ABR) is the most sensitive and specific audiometric test for acoustic neuroma (AN) detection. The ABR sensitivity rate increases with tumor size; consequently, small tumors have notably low ABR sensitivity for detection. However, larger tumors also can fail recognition by ABR testing. The ABR must be viewed on its own merits compared to magnetic resonance imaging studies for the diagnosis of AN. Where does ABR fit into the screening process for detecting AN today?

Cochlea↗
PubMed1996

Psychologic and neuropsychologic impact of autologous bone marrow transplantation.

PURPOSE: The major purpose of the current study was to evaluate the psychologic and neuropsychologic functioning of patients undergoing treatment with autologous bone marrow transplantation (ABMT). PATIENTS AND METHODS: Fifty-four patients with hematologic disorders or breast cancer completed a battery of psychologic and neuropsychologic tests before ABMT, at mid-treatment (1 to 3 days following bone marrow reinfusion), and predischarge (within 1 to 2 days before discharge from the hospital). RESULTS: Analysis of pretransplant data showed significantly higher scores on the State-Trait Anxiety Inventory (STAI) and Profile of Mood States (POMS) for patients with hematologic disorders as compared with patients with breast cancer. However, no baseline differences on neuropsychologic measures were found when patients were divided into groups based on prior exposure to cranial radiation and/or intrathecal chemotherapy. Serial evaluations at pretransplant, following return of bone marrow, and at predischarge were available for 34 patients. For the psychologic data, patients with hematologic disorders tended to be more distressed than breast cancer patients at baseline, but became less distressed over time. By contrast, breast cancer patients were relatively less distressed at baseline, demonstrated a significant increase in distress midtreatment, and returned to baseline levels at predischarge assessment. Scores on neuropsychologic measures that assessed higher order cognitive functioning generally worsened over time. CONCLUSION: The results suggest a differential response on psychologic measures when comparing patients with hematologic disorders with those with breast cancer. However, both groups demonstrated a general decline in performance on neuropsychologic measures over the course of treatment.

Adult↗
PubMed1996

Empowering battered women transnationally: the case for postmodern interventions.

Violence against women by their intimate partners remains a leading cause of injury and death to women worldwide. Governments around the globe are searching for appropriate solutions to woman abuse. This article examines transnational legal interventions instituted to respond to the problem of intimate violence and assesses the propriety of the criminal model on which they are based. Using postmodern social work theory and practice, the article promotes the idea of a more workable alternative response to the problem--a domestic violence commission that places control over her actions and reactions in the hands of the battered woman.

Battered Women↗
PubMed1995

Plasmid analysis of Australian strains of Salmonella enteritidis.

Using an in-well lysis technique, 73 Australian strains of Salmonella enteritidis were shown to possess a large plasmid, similar in size to that possessed by a reference phage type 4 strain. Restriction analysis of the large plasmid from nine strains using EcoRI, HindIII and PstI suggested that these plasmids are similar to or the same as the 38 MDa plasmid described in strains of this species from other parts of the world.

Australia↗
PubMed1993

Chronic hypoxia in vitro increases volume of dissociated carotid body chemoreceptors.

Exposure of humans or animals to chronic hypoxia results in enlargement of the carotid body, a respiratory organ that controls ventilation. The underlying mechanisms are unclear but involve hypertrophy of the chemoreceptor glomus cells. To test whether the latter response can occur independent of the circulation or neural inputs, we exposed cultures of dissociated rat carotid body to chronic hypoxia (2-3 weeks in 6% O2), and compared the 3-D cell volume of immunofluorescent, tyrosine hydroxylase positive (TH+) glomus cells, from data sets obtained by serial confocal microscopy. We found a dramatic increase in volume (3-4 x control) of hypoxia-treated TH + cells, suggesting that glomus cell hypertrophy during chronic hypoxia in vivo is likely due to a local effect of low PO2, rather than the production of ectopic growth factors.

Animals↗
PubMed1993

Brequinar sodium: monitoring immunosuppressive activity.

There has been remarkable consistency in our laboratory for the experimental results derived from a variety of allogeneic and xenogeneic models of organ transplantation using BQR, a primary immunosuppressive agent, to prevent graft rejection. Considerable knowledge exists in a number of species with respect to the dose-response immunosuppressive efficacy, organ specificity, peripheral drug measurements, toxic side-effects, species sensitivity, and synergistic drug interactions. Despite the complexity of transferring experimental results to the clinical setting, the cumulative experience with this new immunosuppressive compound suggests that it may be highly effective when used for clinical transplantation. The identification of a predictive monitoring technique(s) would provide clinicians with a highly sensitive marker to effectively regulate BQR posttransplantation immunosuppressive therapies. Although the maintenance of a "therapeutic window" of immunosuppressive efficacy did not necessarily prevent the rejection of allografts or xenografts in the rat models tested, there was an important correlation between elevated BQR levels and the onset of recipient toxicity. Increased morbidity and mortality was noted when BQR blood levels were elevated above 16 micrograms/mL. The measurement of pyrimidine biosynthetic pathway metabolites provided a direct correlation between graft viability, global depletion of nucleotides (UTP, CTP, ATP, GTP), and suppression of PHA-mitogenic lymphocyte proliferative responses when different doses of BQR were tested. The analysis of these parameters were less informative following combination therapy with CsA. As with other immunosuppressive agents, the difficulty in relying exclusively on plasma trough drug levels as an accurate means to project graft viability may be influenced by individual differences in absorption, metabolism, and excretion of the compound. Additional parameters that may provide valuable information for the posttransplant therapeutic course include drug bioavailability, peak levels, drug clearance, or inhibition of immune response. It is anticipated that these studies will provide important baseline information for further refinement of these monitoring techniques to aid in posttransplant patient management.

Animals↗
PubMed1992

Initial trial of bispecific antibody-mediated immunotherapy of CD15-bearing tumors: cytotoxicity of human tumor cells using a bispecific antibody comprised of anti-CD15 (MoAb PM81) and anti-CD64/Fc gamma RI (MoAb 32).

The high-affinity receptor for IgG, Fc gamma RI, expressed on monocytes and interferon-gamma (IFN-gamma)-stimulated neutrophils, is a trigger molecule for cell-mediated cytotoxicity. We have prepared murine monoclonal antibodies (MoAb 22 and MoAb 32) that bind to Fc gamma RI outside the ligand binding site and thus bind to and trigger cytotoxicity that is not competed by other immunoglobulins. Because of these properties, it seemed that these MoAbs would be very useful for the development of bispecific antibodies (BsAb) for targeting normal cellular immune defense mechanisms as a new form of immunotherapy for treatment of cancer. BsAbs incorporate into a single molecule the binding specifities of two different antibodies, and, thus, can be used to target myeloid cells to tumors, ensure activation of cellular cytotoxic mechanisms, and target cell lysis and/or phagocytosis. BsAbs were prepared using anti-Fc gamma RI MoAb and an anti-myeloid cell MoAb, PM81, reactive with the CD15 antigen, for studies of antibody-dependent cellular cytotoxicity. Conjugates were made by cross-linking sulfhydryl groups of Fab fragments of MoAb 32 or 22 (both IgG1) and sulfhydryl groups added to intact PM81 (an IgM) using N-succinimdyl-acetyl-S-thioacetate (SATA). The resulting product was purified by high-performance size-exclusion chromatography. The ability of the BsAbs to mediate attachment of human monocytes to tumor target cells was confirmed in a microtiter well assay of binding of MTT-labeled U937 cells (a human Fc gamma RI-bearing cell line) to SKBR-3 (PM81-reactive breast carcinoma) target cells. The ability of the BsAbs to mediate killing of HL-60 promyelocytic leukemia cells was studied using a 6-hour Chromium-51 release assay. Effector cells were monocytes obtained by cytopheresis and cultured for 18 hours with IFN-gamma. Monocytes alone caused minimal killing (5-20%), monocytes plus BsAb caused moderate killing (20-50%), and monocytes plus BsAb plus human serum resulted in maximal killing (50-80%). Experiments were performed to test the ability of the BsAb to purge bone marrow of small numbers of leukemia cells using bone marrow mononuclear phagocytes treated for 18 hours with IFN-gamma prior to adding target cells. Without the addition of human serum as a source of complement, a 90% depletion of clonogenic HL-60 cells could be demonstrated. With human complement, up to 95% depletion was seen. Thus, this BsAb possessed the ability to lyse tumor cell targets by two different mechanisms, complement and cell-mediated lysis.(ABSTRACT TRUNCATED AT 400 WORDS)

Antibodies, Monoclonal↗
PubMed1992

Transactivation of the major capsid protein gene of herpes simplex virus type 1 requires a cellular transcription factor.

The purpose of this investigation was to identify and characterize the regulatory elements involved in the transcriptional activation of the beta gamma (leaky-late or gamma 1) genes of herpes simplex virus type 1 (HSV-1) by using the major capsid protein (VP5 or ICP5) gene as model. Gel mobility shift assays with nuclear extracts from uninfected and infected HeLa cells enabled us to identify two major protein-DNA complexes involving the VP5 promoter. The mobilities of these two complexes remained unaltered, and no unique complexes were observed when infected cell nuclear extracts were used. DNase I and orthophenanthroline-Cu+ footprint analyses revealed that the two complexes involve a single binding site, GGCCATCTTGAA, located between -64 and -75 bp relative to the VP5 cap site. To determine the function of this leaky-late binding site (LBS) in VP5 gene activation, we tested the effect of mutations in this region by using transient expression of a cis-linked chloramphenicol acetyltransferase gene. Deletion of the above sequence resulted in a seven- to eightfold reduction in the level of transactivation of the chloramphenicol acetyltransferase gene by superinfection with HSV-1 or by cotransfection of HSV-1 immediate-early genes. From these results, we conclude that the LBS sequence and a cellular factor(s) are involved in the transactivation of the VP5 gene. A search of published gene sequences revealed that sequences related to the LBS exist in a number of other HSV-1, cytomegalovirus, retrovirus, and cellular promoters. Sequence homologies of binding sites and results of unpublished competition binding studies suggest that this leaky-late binding factor may be related to, or the same as, a ubiquitous cellular transcriptional factor called YY1 or common factor-1 (also known as NF-E1, delta, and UCRBP).

Base Sequence↗
PubMed1992

The sensitivity of auditory brainstem response testing in small acoustic neuromas.

Auditory brainstem response (ABR) testing is a reliable and sensitive test for retrocochlear pathology in neurotologic diagnosis. Several investigators have reported the sensitivity of ABR testing as 95% or greater. Fifty-one consecutive patients with surgically confirmed acoustic neuromas were examined. Forty patients had sufficient hearing preoperatively for assessment with ABR. In addition, all had been evaluated with gadolinium-enhanced magnetic resonance imaging and conventional electronystagmography. Overall, 34 of 40 patients (85%) had abnormal ABRs. One of 25 patients with extracanalicular tumors had a normal ABR for a false-negative rate of 4%; however, 5 of 15 patients with intracanalicular tumors had normal ABRs for a false-negative rate of 33%. Tumor size and nerve of origin were important factors affecting the ABR sensitivity. The ABR was less sensitive in detecting intracanalicular tumors than in detecting extracanalicular tumors.

Audiometry, Pure-Tone↗