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Biomedical subjects

A Miller

Publications and source records attributed to A Miller.

At least 199 records · Page 11Linked to original sources
PubMed1997

Comparison of two different methods for inactivation of viruses in serum.

In order to compare protocols for inactivation of viruses potentially present in biological specimens, three different model viruses were treated in bovine serum by two different inactivation methods: samples were subjected either to chemical inactivation with ethylenimine (El) at concentrations of 5 and 10 mM at 37 degrees C for periods up to 72 h or to electron-beam irradiation in frozen and liquid form with doses varying between 11 and 46 kGy. The chemical inactivation resulted in nonlinear tailing curves in a semilogarithmic plot of virus titer versus inactivation time showing non-first-order kinetics with respect to virus titer. The time for inactivation of 7 log10 units of porcine parvovirus (PPV) was about 24 h for both El concentrations, whereas 5 log10 units of bovine viral diarrhea virus (BVDV) was inactivated in 2 h for both El concentrations and 6 log10 units of porcine enterovirus (PEV) was inactivated within 3 h. The inactivation with electron-beam irradiation resulted in almost linear curves in a semilogarithmic plot of virus titer versus irradiation dose, reflecting a first-order inactivation. The rate of inactivation was almost twice as fast in the liquid samples compared to the rate in frozen ones, giving values of the doses needed to reduce virus infectivity 1 log10 unit for inactivation of PPV of 11.8 and 7.7 kGy for frozen and liquid samples, respectively, whereas the corresponding values for BVDV were 4.9 and 2.5 kGy, respectively, and those for PEV were 6.4 and 4.4 kGy, respectively. The nonlinear inactivation with El makes it impossible to extrapolate the curves beyond the virus detection limit and thereby predict the necessary time for complete inactivation, i.e., to a level beyond the detection limit, of virus in a given sample. The first-order inactivation obtained with electron-beam irradiation makes such a prediction possible and justifiable. The two methods are discussed with respect to their different kinetics and applicability under different circumstances and criteria for inactivation, and considerations for choice of method are discussed.

Animals↗
PubMed1997

Tumor necrosis factor-alpha. A mediator of focal ischemic brain injury.

BACKGROUND AND PURPOSE: Tumor necrosis factor-alpha (TNF-alpha) is a pleiotropic cytokine that rapidly upregulates in the brain after injury. The present study was designed to explore the pathophysiological significance of brain TNF-alpha in the ischemic brain by systematically evaluating the effects of lateral cerebroventricular administration of exogenous TNF-alpha and agents that block the effects of TNF-alpha on focal stroke and by examining the potential direct toxic effects of TNF-alpha on cultured neurons to better understand how TNF-alpha might mediate stroke injury. METHODS: TNF-alpha (2.5 or 25 pmol) was administered intracerebroventricularly to spontaneously hypertensive rats 24 hours before permanent or transient (80 minutes and 160 minutes) middle cerebral artery occlusion (MCAO). Animals were examined 24 hours later for neurological deficits and ischemic hemisphere necrosis and swelling. In some of these studies, neutralizing anti-TNF-alpha monoclonal antibody (mAb) (60 pmol) was injected intracerebroventricularly 30 minutes before exogenous TNF-alpha (25 pmol). In addition, the effects of blocking endogenous TNF-alpha on permanent focal ischemic injury were determined with the use of either mAb (60 pmol) or soluble TNF receptor I (sTNF-RI) (0.3 or 0.7 nmol) administered intracerebroventricularly 30 minutes before and 3 and 6 hours after MCAO. Finally, the direct neurotoxic effects of TNF-alpha were studied in cultured rat cerebellar granule cells exposed to TNF-alpha (10 to 2000 U/mL for 6 to 24 hours), and neurotransmitter release, glutamate toxicity, and oxygen radical toxicity were studied. RESULTS: TNF-alpha increased the percent hemispheric infarct induced by permanent MCAO in a dose-related manner from 13.1 +/- 1.3% (vehicle) to 18.9 +/- 1.7% at 2.5 pmol (P < .05) and 27.1 +/- 1.3% at 25 pmol (P < .0001). The high dose of TNF-alpha increased ischemia-induced forelimb deficits from 1.6 +/- 0.2 to 2.3 +/- 0.2 (P < 0.1). TNF-alpha (2.5 pmol) also increased the infarction induced by 80 or 160 minutes of transient MCAO from 1.9 +/- 0.9% to 4.3 +/- 0.4% (P < .01) and from 14.2 +/- 1.3% to 21.6 +/- 2.2% (P < .05), respectively. The exacerbation of infarct size, swelling, and neurological deficit after exogenous TNF-alpha was reversed by preinjection of 60 pmol mAb. Blocking endogenous TNF-alpha also significantly reduced focal ischemic brain injury. Treatment with 60 pmol mAb before and after permanent MCAO significantly reduced infarct size compared with control (nonimmune) antibody treatment by 20.2% (P < .05). Reduced brain infarction also was produced by brain administration of 0.3 nmol (decreased 18.2%) or 0.7 nmol (decreased 26.1%, P < .05) sTNF-RI before and after focal stroke. The intracerebroventricular administration of TNF-alpha or sTNF-RI did not alter brain or body temperature, blood gases or pH, blood pressure, blood glucose, or general blood chemistry. In cultured cerebellar granule cells, the application of TNF-alpha did not directly affect neurotransmitter release or glutamate or oxygen free radical toxicity. CONCLUSIONS: These studies demonstrate that exogenous TNF-alpha exacerbates focal ischemic injury and that blocking endogenous TNF-alpha is neuroprotective. The specificity of the action(s) of TNF-alpha was demonstrated by antagonism of its effects with specific anti-TNF-alpha tools (ie, mAb and sTNF-RI). TNF-alpha toxicity does not appear to be due to a direct effect on neurons or modulation of neuronal sensitivity to glutamate or oxygen radicals and apparently is mediated through nonneuronal cells. These data suggest that inhibiting TNF-alpha may represent a novel pharmacological strategy to treat ischemic stroke.

Animals↗
PubMed1997

Pulmonary involvement in Fabry disease.

Fabry disease is an X-linked inborn error of metabolism resulting from deficient activity of alpha-galactosidase A. Although several case reports have suggested an association between Fabry disease and airway obstruction, this has not been investigated in a large series of patients. We studied 25 unselected, consecutive, enzymatically diagnosed men referred to a General Clinical Research Center for evaluation. Thirty-six percent complained of dyspnea, and 24% had cough and/or wheezing. Symptoms were similar in smokers and nonsmokers. Nine (36%) had airway obstruction on spirometry; this finding was associated with age > or = 26 yr (p < 0.05) and dyspnea or wheezing (p < 0.005), but only weakly with smoking (p = 0.062). Five of eight patients responded to bronchodilators, but all 10 methacholine challenges were negative. Chest radiographs revealed normal lung fields in 24 patients and streaky bibasilar densities in one. No pulmonary uptake occurred on 67Ga citrate scans (18 patients) and 111In-tagged leukocyte scans (16 patients). Specific alpha-galactosidase A mutations were identified in 17 patients; all three patients with frameshift mutations and both subjects with the D264V missense mutation had obstructive impairment. We conclude that airway obstruction commonly occurs in patients with Fabry disease regardless of smoking history, and it increases with age. The presence of obstruction may be associated with certain mutations and most likely results from fixed narrowing of the airways by accumulated glycosphingolipid.

Adolescent↗
PubMed1997

Clinical predictors of mortality from asbestosis in the North American Insulator Cohort, 1981 to 1991.

Recorded mortality from asbestosis has increased markedly in the United States in recent decades, from 0.49 to 3.06 per million persons between 1970 and 1990. Although asbestosis is generally considered to be a slowly progressive disorder, little is known about how clinical and exposure parameters among individuals with asbestosis quantitatively predict subsequent risk of death from asbestosis. We followed 2,609 insulators from the North American insulator cohort 10 yr to determine cause of death and to relate clinical findings to risk of death. This group had undergone clinical and radiologic examination between 1981 and 1983 in 19 cities in the United States. Seventy-four (11.0%) of 674 deaths during the subsequent 10 yr were due to asbestosis, according to the best clinical and radiologic evidence available at the time of death. The 10 yr risk of death (expressed as a percentage) due to asbestosis rose sharply with increasing interstitial fibrosis as identified on the baseline chest X-ray, from 0.9% to 2.4%, 10.8%, and 35.4% for International Labor Office (ILO) profusion categories 0, 1, 2, and 3, respectively. Dyspnea, a low FVC, and/or physical examination findings typical of interstitial fibrosis (rales, clubbing, or cyanosis) raised the risk of subsequent death from asbestosis by 2- to 6-fold. The effect of cigarette smoking on risk of death from asbestosis was small and disappeared after adjustment for ILO profusion score.

Analysis of Variance↗
PubMed1997

Influenza virus vaccination of patients with multiple sclerosis.

Prior to vaccination with a trivalent influenza vaccine (AT/Texas, AB/Beijing, and BP/Panama), sera from 19 MS patients had a significantly higher mean level of antibody than 9 normal subjects to AT strain of influenza, but not to AB or BP strains. After Flu vaccination, the mean anti-AT and anti-AB antibody titers significantly increased 4-fold in 11 MS patients and 9 normal subjects. The ratio of MS responders (6/11), however, was lower than normal (8/9). The mean PBL proliferative response to the Flu antigens increased after vaccination significantly more in MS patients than in normal subjects, and increased in 9 of 11 MS patients and 3 of 9 normal subjects. Although MS patients responded to Flu antigens with higher antibody levels and proliferative responses of PBL, than normal subjects, a clinical protective effect of the vaccine against Flu was not clearly demonstrated in these patients, and vaccination did not cause or protect against exacerbation of MS.

Adult↗
PubMed1997

Noninvasive measurement of cardiac output by an acetylene uptake technique and simultaneous comparison with thermodilution in ICU patients.

A simple, accurate, and noninvasive method of cardiac output measurement can be an extremely useful tool for the clinician and researcher. This study used the acetylene gas uptake technique to measure the absorption of acetylene into the pulmonary circulation during a constant exhalation, which is proportional to the pulmonary capillary blood flow and to the cardiac output, assuming no anatomic shunts. We compared cardiac output measured simultaneously by this and by the standard thermodilution (TD) technique in 21 patients in the ICU with a variety of medical and surgical conditions and a wide range of cardiac outputs. We also compared the two techniques in 19 ambulatory patients with a 2-h interval between the invasive and noninvasive test to assess variability over time. The two tests had an excellent correlation when done simultaneously with a correlation coefficient of 0.89 (p < 0.001). With a 2-h interval between the two tests, the correlation coefficient was 0.66 (p = 0.0018). Nine patients in the simultaneous group had cardiomyopathy. When they were excluded, the correlation coefficient increased to 0.96. Most of these patients had documented tricuspid regurgitation (TR), which may underlie the greater difference between acetylene uptake and TD values, with consistently higher TD values in these patients. This study confirms the correlation between the acetylene uptake and the standard invasive TD techniques in sick patients with various medical and surgical conditions and a wide range of cardiac outputs. Furthermore, we believe this would be a more accurate method for measuring cardiac output in patients with cardiomyopathy and TR because it is based only on pulmonary capillary blood flow.

Absorption↗
PubMed1997

The influence of mouse housing density on autoimmune reactivity.

Splenic cells from C57BL/6 mice housed in groups (six per cage) or individually (one per cage) were analyzed for their ability to synthesize autoantibodies against autologous bromelain-treated erythrocytes. Group-housed male mice had a significantly lower number of autoimmune plaque forming cells (APFC) in their spleens than age matched female mice housed under similar conditions. However, when male mice were housed individually for 4 to 44 weeks, a marked increase in numbers of APFC were found in their spleens, approaching those of female control mice. Our results demonstrate that a simple environmental manipulation such as housing conditions can profoundly modulate autoimmune reactivity. Thus, alteration of the psychophysiological state determined by the quality of housing may significantly affect the development of autoimmune disease.

Animals↗
PubMed1997

Vasculitis and thrombotic thrombocytopenic purpura in a patient with limited scleroderma.

Inflammatory vasculopathy and thrombotic thrombocytopenic purpura (TTP) are rare complications of scleroderma. We report a 54-year-old woman with limited cutaneous scleroderma who developed medium size and small vessel vasculitis. Inflammatory changes of medium size muscular arteries presented as ovarian vasculitis and mononeuritis multiplex, while arteriolar involvement presented as TTP with associated central nervous system involvement. In addition, possible noninflammatory involvement of small muscular arteries was expressed as Raynaud's phenomenon.

Female↗
PubMed1997

Bilateral condylar movement patterns in adult subjects.

The purpose of this study was to determine if there was a difference between the temporomandibular condylar movement patterns of a symptomatic adult population and those of an asymptomatic adult population. Thirty-five volunteers who were not seeking treatment for TMD underwent two different assessments for TMD signs and symptoms: (1) a self-administered questionnaire and (2) a clinical examination. Based on the information obtained from the questionnaires, subjects were divided into "reported-symptomatic" and "reported-asymptomatic" groups. Based on the investigator's clinically evaluation of the same subjects, subjects were divided into "clinically symptomatic" and "clinically asymptomatic" groups. To compare condylar movement patterns, both groups of subjects then had their mandibular border condylar movements measured bilaterally using a sagittal recording device during maximum opening, maximum protrusion, and maximum left and right excursion movements. The patterns were separated into two broad groups, "symmetric" and "asymmetric." Symmetric gliding movements were defined as uninterrupted bilaterally mirror-like patterns of each condyle with a difference between left and right total length excursion not exceeding 2 mm during opening in the sagittal plane or horizontal plane. Our results show that 63% of the subjects who reported clinically asymptomatic for TMD demonstrated asymmetric condylar movements. However, 100% of the patients (n = 5) who reported clinically symptomatic for TMD exhibited asymmetric condylar movements. This finding suggests that, while a very high percentage of TMD subjects will have asymmetric condylar movements, condylar movements alone are not necessarily diagnostic of TMD, and the sagittal recording device may alert the clinician to abnormal movements.

Adult↗
PubMed1996

Mutations in the B2 bradykinin receptor reveal a different pattern of contacts for peptidic agonists and peptidic antagonists.

The B2 bradykinin receptor, a seven-helix transmembrane receptor, binds the inflammatory mediator bradykinin (BK) and the structurally related peptide antagonist HOE-140. The binding of HOE-140 and the binding of bradykinin are mutually exclusive and competitive. Fifty-four site-specific receptor mutations were made. BK's affinity is reduced 2200-fold by F261A, 490-fold by T265A, 60-fold by D286A, and 3-10-fold by N200A, D268A, and Q290A. In contrast, HOE-140 affinity is reduced less than 7-fold by F254A, F261A, Y297A, and Q262A. The almost complete discordance of mutations that affect BK binding versus HOE-140 binding is surprising, but it was paralleled by the effect of single changes in BK and HOE-140. [Ala9]BK and [Ala6]BK are reduced in receptor binding affinity 27,000- and 150-fold, respectively, while [Ala9]HOE-140 affinity is reduced 7-fold and [Ala6]HOE-140 affinity is unchanged. NMR spectroscopy of all of the peptidic analogs of BK or HOE-140 revealed a beta-turn at the C terminus. Models of the receptor-ligand complex suggested that bradykinin is bound partially inside the helical bundle of the receptor with the amino terminus emerging from the extracellular side of helical bundle. In these models a salt bridge occurs between Arg9 and Asp286; the models also place Phe8 in a hydrophobic pocket midway through the transmembrane region. Models of HOE-140 binding to the receptor place its beta-turn one alpha-helical turn deeper and closer to helix 7 and helix 1 as compared with bradykinin-receptor complex models.

Adrenergic beta-Antagonists↗
PubMed1996

Proton magnetic resonance studies of methionine enkephalin.

In the literature there exist two conflicting pieces of data concerning the thermodynamics of the Cu(2+)-methionine enkephalin complex. One study utilized 1H nuclear magnetic resonance (NMR) to study the solution phase Cu(2+)-enkephalin binding and reported a strong interaction over a wide pH range. Another study utilized potentiometry to measure a log beta 101 of 4.6, a value representative of a weak metal-ligand complex. In order to resolve this discrepancy a 300 MHz 1H NMR is used to study the protonation sequence of methionine enkaphalin, a bioactive peptide, and its complexation with seven diamagnetic metals (Ba2+, Ca2+, Zn2+, La2+, Mg2+, Sr2+ and Cd2+).

Acetic Acid↗
PubMed1996

In vivo trafficking of adoptively transferred interleukin-2 expanded tumor-infiltrating lymphocytes and peripheral blood lymphocytes. Results of a double gene marking trial.

Adoptive immunotherapy with tumor-infiltrating lymphocytes (TIL) and IL-2 appears to produce dramatic regressions in patients with metastatic melanoma and renal cancer. However, the in vivo mechanism of TIL function is not known. We conducted an UCLA Human Subject Protection Committee, Recombinant DNA Advisory Committee, and FDA-approved clinical trial using genetically-marked TIL to test the hypothesis that these cells have unique, tumor-specific in vivo trafficking patterns. TIL and PBL (as a control effector cell population) were isolated and expanded in parallel in vitro in IL-2-containing medium for 4-6 wk. During the expansion, TIL and PBL were separately transduced with the amphotropic retroviral vectors LNL6 and G1Na. Transduced TIL and PBL were coinfused into patients and their respective numbers measured in tumor, peripheral blood, and normal tissues; integrated provirus could be quantitated and distinguished by DNA PCR. Nine patients were treated (six melanoma, three renal) and received between 4.5 x 10(8) and 1.24 x 10(10) total cells. Both "marked" TIL and PBL could be detected circulating in the peripheral blood, in some patients for up to 99 d after infusion. Marked TIL and/or PBL could be detected in tumor biopsies in six of nine patients as early as day 6 and as late as day 99 after infusion. No convincing pattern of preferential trafficking of TIL vs. PBL to tumor was noted. Moreover, concurrent biopsies of muscle, fat, and skin demonstrated the presence of TIL/PBL in comparable or greater numbers than in tumor in five patients. The results of this double gene marking trial provide interesting insights into the life span and trafficking of adoptively transferred lymphocytes, but do not support the hypothesis that TIL specifically traffic to tumor deposits.

Adult↗
PubMed1996

Clinical outcomes assessment in multiple sclerosis.

This article represents initial deliberation of an international task force appointed by the US National Multiple Sclerosis Society to develop recommendations for optimal clinical assessment tools for multiple sclerosis clinical trials. Presented within this article are the key issues identified by the task force during its initial year of deliberation. These include the precise purpose for a clinical assessment tool, the clinical dimensions to be measured in a multidimensional outcome measure, desirable attributes of an optimal clinical outcome measure, the complexities of multidimensional outcome measures, the relative merits of categorical clinical ratings and quantitative functional assessments, and a number of other important design issues that relate to the use of a multidimensional outcome measure. An action plan for analysis of existing data is summarized, as are the plans for more detailed recommendations from the task force.

Clinical Trials as Topic↗
PubMed1996

Phase 1 trial of intraperitoneal AD-32 in gynecologic malignancies.

AD-32 (N-trifluoroacetyladriamycin-14-valerate), an analogue of doxorubicin, was examined for intraperitoneal (ip) administration in a phase 2 trial involving 25 patients with advanced gynecologic malignancies. At an AD-32 dose of 600 mg/m2, the limiting toxicity was grade 4 neutropenia (64% of patients), while severe abdominal pain was relatively uncommon (12%). Intraperitoneal AD-32 administration was associated with a 200-fold pharmacokinetic advantage for cavity exposure, compared to the systemic compartment. At the 600 mg/m2 dose level, 4 of 9 patients (44%) with ascites experienced control of malignant fluid reaccumulation. Based on the results of this phase 1 trial, further exploration of a possible role for the ip administration of AD-32 in individuals with gynecological malignancies appears indicated, particularly in patients with either small volume residual disease after initial systemic chemotherapy or in those with intractable ascites.

Aged↗