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D J Miller

Publications and source records attributed to D J Miller.

At least 73 records · Page 4Linked to original sources
PubMed1998

Targeting of IgMkappa antibodies to oligodendrocytes promotes CNS remyelination.

We previously identified the remyelinating activity of a natural IgMkappa oligodendrocyte-reactive autoantibody (SCH94.03), using a virus-induced murine model of multiple sclerosis. We now describe a second mouse IgMkappa monoclonal antibody (mAb) (SCH79.08) raised against normal mouse spinal cord homogenate, which reacts with myelin basic protein and also promotes remyelination. Because these two mAbs recognize different oligodendrocyte antigens, several previously identified oligodendrocyte-reactive IgMkappa mAbs (O1, O4, A2B5, and HNK-1), each with distinct antigen specificities, were evaluated and found to promote remyelination. In contrast, IgMkappa mAbs that did not bind to oligodendrocytes showed no remyelination. One of these, CH12 IgMkappa mAb, which shares variable region cDNA sequences with SCH94.03 except for amino acid differences in the complementarity-determining region 3 in both heavy and light chains, did not bind to oligodendrocytes and did not promote remyelination. The fact that multiple oligodendrocyte-reactive antibodies with distinct antigen reactivities induce remyelination argues against direct activation by a unique cell surface receptor. These findings are most consistent with the hypothesis that the binding of mAbs to oligodendrocytes in the lesions induces myelin repair via indirect immune effector mechanisms initiated by the mu-chain. Importantly, these studies indicate that oligodendrocyte-reactive natural autoantibodies may provide a powerful and novel therapeutic means to induce remyelination in multiple sclerosis patients.

Animals↗
PubMed1998

Linkage of genes encoding enolase (eno) and CTP synthase (pyrG) in the beta-subdivision proteobacterium Nitrosomonas europaea.

The gene encoding enolase (eno) from the ammonia oxidising bacterium Nitrosomonas europaea has been cloned and sequenced. The deduced amino acid sequence for enolase from N. europaea was 65% identical (76% similar) to its Bacillus subtilis orthologue. An incomplete open reading frame located 432 bp 5' of eno was identified as pyrG, which encodes CTP synthase. These two genes are therefore organised in N. europaea, a beta-subdivision proteobacterium, in the same way as in the gamma-subdivision proteobacterium Escherichia coli.

Amino Acid Sequence↗
PubMed1998

Method for determining the solubilities of hydrophobic organics in subcritical water.

A rapid and simple method has been developed to determine the solubility of organic compounds in water at temperatures from 25 to 250 degrees C and with enough pressure to maintain the liquid state ("subcritical" water). Water is heated and then passed through a cell containing excess test solute. The water, now saturated with solute, is blended with chloroform, cooled, and collected, and the chloroform fraction is analyzed by gas chromatography. Replicate determinations have typical reproducibilities, indicated by the relative standard deviation, of < 5%. Solubilities at 25 degrees C determined by this method are in good agreement with published data. Increasing the temperature of water from 25 degrees C to near the normal melting point of the organic solute results in solubility enhancements ranging from 6-fold for naphthalene (at 65 vs 25 degrees C) to 130,000-fold for chlorothalonil (at 200 vs 25 degrees C).

Benzo(a)pyrene↗
PubMed1998

The accuracy of substituted judgments in patients with terminal diagnoses.

BACKGROUND: Patients' loved ones often make end-of-life treatment decisions, but the accuracy of their substituted judgments and the factors associated with accuracy are poorly understood. OBJECTIVE: To assess the accuracy of judgments made by surrogate decision makers; ascertain the beliefs, practices, and clinical and sociodemographic factors associated with accuracy of surrogates' decisions; assess the preferences of patients for life-sustaining treatments; and compare differences in accuracy across diagnoses. DESIGN: Cross-sectional paired interviews. SETTING: Outpatient practices of three university hospitals. PATIENTS: 250 patients with terminal diagnoses of congestive heart failure, AIDS, amyotrophic lateral sclerosis, lung cancer, and chronic obstructive pulmonary disease (50 patient-surrogate pairs in each group) and 50 general medical patients and their surrogates. MEASUREMENTS: The accuracy of surrogate predictions was measured by using scales based on 10 potential treatments in each of three hypothetical clinical scenarios. RESULTS: Preferences varied according to mode of treatment and scenario. On average, surrogates made correct predictions in 66% of instances. Accuracy was better for the permanent coma scenario than for the scenarios of severe dementia or coma with a small chance of recovery (P < 0.001). In a binary logit model, the accuracy of substituted judgments was positively associated with the patient having spoken with the surrogate about end-of-life issues (odds ratio [OR], 1.9 [95% CI, 1.6 to 2.3]), the patient having private insurance (OR, 1.4 [CI, 1.1 to 1.7]), the surrogate's level of education (OR, 1.5 [CI, 1.2 to 1.9]), and the patient's level of education (OR, 1.7 [CI, 1.4 to 2.2]). Accuracy was negatively associated with the patient's belief that he or she would live longer than 10 years (OR, 0.6 [CI, 0.5 to 0.7]), surrogate experience with life-sustaining treatment (OR, 0.4 [CI, 0.3 to 0.5]), surrogate participation in religious services (OR, 0.67 [CI, 0.50 to 0.91]), and a diagnosis of heart failure (OR, 0.6 [CI, 0.5 to 0.8]). Age, ethnicity, marital status, religion, and advance directives were not associated with accuracy. CONCLUSIONS: The accuracy of substituted judgments is associated with multiple clinically apparent patient and surrogate factors. This information can help clinicians identify conditions under which substituted judgments are likely to be accurate or inaccurate and can help target populations for education designed to improve the accuracy of surrogate decision making.

Adult↗
PubMed1998

Solid-phase microextraction of polychlorinated biphenyls.

The extraction and analysis of 21 polychlorinated biphenyls (PCBs) ranging from di- to decachlorobiphenyls in ocean, wetland and leachate water samples were achieved using solid-phase microextraction (SPME) with a 100-micron poly(di-methylsiloxane) (PDMS) fiber and gas chromatography-electron-capture detection (GC-ECD). Severe carryover between samples (e.g., 20%) occurs on both stir bars and the SPME fibers demonstrating that it is important to use a new stir bar for each sample, as well as to perform SPME-GC blanks between samples to avoid quantitative errors. The equilibrium partitioning coefficients of individual PCB congeners between PDMS and water were found to be surprisingly different compared to their octanol-water partitioning coefficient (Kow), demonstrating that Kow cannot be used to estimate the partitioning behavior of PCBs in the SPME process. Using a 15-min SPME extraction, SPME analysis with GC-ECD was linear (r2 > or = 0.97) from approximately 5 pg/ml to the solubility limit of each congener. Concentrations in water samples obtained by 15-min SPME extractions compared favorably with those obtained by toluene extractions, demonstrating that SPME combined with GC is a useful technique for the rapid determination of PCBs in water samples.

Absorption↗
PubMed1998

Identification of a novel family of non-lysosomal aspartic proteases in nematodes.

A protein encoded by cDNAs from the human parasite Onchocerca volvulus and its homologs from Caenorhabditis elegans and Ancyclostoma caninum define a family of aspartic proteases that are most closely related to cathepsins D, but differ from them in lacking the N-glycosylation site known to be required for lysosomal targeting. The nematode proteins have a potential N-glycosylation site at the same position as mammalian cathepsins E and in common with these have atypically long N-terminal extensions. The literature implies that cathepsins E may be secreted, and adult female O. volvulus are known to secrete a specific inhibitor of aspartic proteases; we therefore predict that the protease is secreted as an enzyme-inhibitor complex.

Amino Acid Sequence↗
PubMed1998

Effects of cyclic adenosine monophosphate (cAMP) on sarcoplasmic reticulum Ca(2+)-loading in failing rabbit and human cardiac trabeculae.

The response of cardiac SR Ca(2+)-loading to cAMP in failing rabbit and human myocardium was examined. Right ventricular (RV) trabeculae were isolated and mounted for isometric tension measurement. They were treated with saponin to permeabilise the sarcolemma but retain SR function, and bathed in a mock intracellular solution including adenosine triphosphate (ATP) and buffered calcium. Caffeine (10 mM) was used to release calcium from the SR. The amplitude of the caffeine-induced contracture was used as a quantitative gauge of the calcium content of the SR. Trabeculae were isolated from rabbits with coronary ligation-induced heart failure (LIG, n = 11), sham operated controls (SH, n = 10), isoprenaline-infused rabbits (ISO, 7 days mini-osmotic pump 100 micrograms/kg.h; n = 7) and saline-infused controls (SAL, n = 7). Failing human RV trabeculae were obtained at the time of cardiac transplantation. Failing rabbit trabeculae demonstrated increased baseline caffeine-induced contractures compared with controls, the response to cAMP was similar in the two groups (LIG 9.3 +/- 2.8 vs SH 10.6 +/- 3.2% Fmax; P = 0.55), There was no difference in the baseline SR Ca(2+)-loading in ISO trabeculae compared with SAL controls but there was a marked difference in the response to cAMP (11.1 +/- 5.4 vs 4.2 +/- 2.1% Fmax, P = 0.02). SR Ca(2+)-loading in failing human RV trabeculae was related to the severity of LV dysfunction (r = 0.59, P = 0.04) and demonstrated a marked cAMP-induced enhancement of caffeine-contracture (20.2 +/- 4.7% increase of Fmax) which was greater in patients with low compared with high ejection fraction. While beta-receptors are known to be down regulated in heart failure these results suggest that the scope for cAMP-mediated enhancement of SR Ca(2+)-loading is maintained.

Actin Cytoskeleton↗
PubMed1998

Sarcoplasmic reticulum Ca2+ loading in rabbits 8 and 15 weeks after coronary artery ligation.

Calcium uptake by cardiac sarcoplasmic reticulum (SR) is reported to be reduced in heart failure in the human and in a number of animal models. However, the majority of studies have examined end-stage heart failure in the human and few animal studies have taken account of the duration and severity of left ventricular dysfunction. In this study we have compared SR Ca2+ loading in a haemodynamically assessed, coronary artery ligation model of heart failure at 8 and 15 weeks after ligation. Trabeculae were isolated from the right ventricle and mounted for isometric tension measurement. They were treated with saponin to permeabilize the sarcolemma but retain SR function and bathed in a mock intracellular solution including adenosine triphosphate (ATP) and buffered Ca2+. Caffeine was used to release Ca2+ from the SR. The amplitude of the caffeine-induced contracture was used as a quantitative gauge of the Ca2+ content of the SR. Eight weeks after ligation, trabeculae demonstrated enhanced SR Ca2+ uptake as manifest by larger caffeine-induced contractures (e.g. 200 nM [Ca2+], 120 s loading - 38.2+/-9.2 versus 67.3+/-10.1% of maximum Ca2+-activated force, FCa, max, P=0.03). At 15 weeks, trabeculae from ligated hearts were not significantly different from controls with SR Ca2+ loading returning to control levels (e.g. 200 nM [Ca2+], 120 s loading - 47.3+/-9.6 versus 30.2+/-12.8% FCa, max, P=0.12). These data suggest that SR Ca2+ loading may increase in the early stages of heart failure and fall back to normal with an increasing duration of left ventricular dysfunction. Increased incidence of spontaneous Ca2+ release observed from the SR at 8 weeks and not at 15 weeks may represent an arrhythmogenic mechanism specific to the early phase of heart failure.

Animals↗
PubMed1998

Pax-6 origins--implications from the structure of two coral pax genes.

Vertebrate Pax-6 and its Drosophila homolog eyeless play central roles in eye specification, although it is not clear if this represents the ancestral role of this gene class. As the most "primitive" animals with true nervous systems, the Cnidaria may be informative in terms of the evolution of the Pax gene family. For this reason we surveyed the Pax gene complement of a representative of the basal cnidarian class (the Anthozoa), the coral Acropora millepora. cDNAs encoding two coral Pax proteins were isolated. Pax-Aam encoded a protein containing only a paired domain, whereas Pax-Cam also contained a homeodomain clearly related to those in the Pax-6 family. The paired domains in both proteins most resembled the vertebrate Pax-2/5/8 class, but shared several distinctive substitutions. As in most Pax-6 homologs and orthologs, an intron was present in the Pax-Cam locus at a position corresponding to residues 46/47 in the homeodomain. We propose a model for evolution of the Pax family, in which the ancestor of all of the vertebrate Pax genes most resembled Pax-6, and arose via fusion of a Pax-Aam-like gene (encoding only a paired domain) with an anteriorly-expressed homeobox gene resembling the paired-like class.

Amino Acid Sequence↗
PubMed1998

Analysis of an H1 receptor-mediated, zinc-potentiated vasoconstrictor action of the histidyl dipeptide carnosine in rabbit saphenous vein.

The contractile action of the dipeptide carnosine (beta-alanyl-L-histidine), active as a Zn.carnosine complex (Zn. Carn), was investigated in isolated rings of rabbit saphenous vein (RSV) and was found to be antagonized by the H1 antagonist mepyramine. Mepyramine-sensitive, histamine-induced contractures in RSV, were smaller (73+/-0.1%) and less well sustained than carnosine-induced contractures. Schild plot values for mepyramine antagonism were, for carnosine-induced contractures; pA2 = 7.97+/-0.12, slope= 1.33+/-0.06 (r = 0.793) and for histamine-induced contractures; pA2 = 8.48+/-0.07, slope = 0.63+/-0.05, r = 0.957). Serotonergic antagonists methiothepin and ketanserin, antagonize both carnosine- and histamine-induced contractures in RSV, probably reflecting coincidental inhibition at the H1-receptor. Carnosine, with Zn present, can inhibit the H1-specific binding of [3H]-mepyramine to isolated guinea-pig cerebellar membranes (log IC50s - 2.78+/-0.02, -3.93+/-0.03 and -4.64+/-0.03 at 10, 30 and 80 microM Zn respectively; values corrected for the Zn-specific inhibition which has a logIC50 of -4.20). In the radioligand binding assay, the effect of carnosine can be described as a function of Zn. Carn concentration with an apparent logIC50 of -5.61. This value is consistent with that obtained from the functional studies on RSV. Histamine-induced contractures have an indomethacine-sensitive component (27.2+/-8.3% of control response), not apparent with carnosine-induced contractures. Like histamine, carnosine evoked an H2-mediated (cimetidine-sensitive) relaxation in the presence of mepyramine, but was less potent (10.8+/-3.1% residual tension at 10 mM carnosine compared with 13.4+7.5% at 0.1 mM histamine). Carnosine, like mepyramine, can 'reveal' the H2-mediated relaxation of histamine providing further evidence that carnosine binds at the H1 receptor. We conclude that carnosine can act at the smooth muscle H1-receptor to provoke vasoconstriction and that it also has the potential to act at H1-receptors in CNS.

Animals↗
PubMed1998

Physical therapists' opinions and practices regarding direct access.

BACKGROUND AND PURPOSE: This study examined whether differences exist about physical therapists' opinions and practices regarding the use of direct access between therapists practicing in Massachusetts, a direct-access state, and therapists practicing in Connecticut, a state that allows only evaluation without referral. A second purpose was to examine direct-access practices of therapists in Massachusetts. SUBJECTS: A sample of 329 therapists in Massachusetts and 179 therapists in Connecticut were surveyed. METHODS: A cover letter, questionnaire, and return-reply envelope were mailed to each therapist. Independent group t tests and chi-square analyses were used to determine whether therapists' opinions about direct access differed between states. Frequencies were calculated to examine direct-access practices of therapists in Massachusetts. RESULTS: Adjusted response rates were 65.5% in Massachusetts and 57.9% in Connecticut. Therapists in both states were equally supportive of direct access (74.9%). Therapists in Connecticut were more supportive of three stipulations regulating direct access than therapists in Massachusetts were. In Massachusetts, 34.0% of the respondents stated that they practiced using direct access, and 8.8% of the patients seen by the therapists sampled were treated without physicians' referrals. The therapists indicated that the most common reasons for limited use of direct access were employer policies and lack of insurance reimbursement. CONCLUSION AND DISCUSSION: Therapists in Connecticut favored more stipulation regulating direct access than therapists in Massachusetts did. Although therapists in both states appear to be supportive of direct access, the number of patients in Massachusetts seen through this mode of care appears to be limited because of practice and financial restraints.

Adult↗
PubMed1998

Effects of in vitro and in vivo exposure to doxorubicin (adriamycin) on caffeine-induced Ca2+ release from sarcoplasmic reticulum and contractile protein function in 'chemically-skinned' rabbit ventricular trabeculae.

Doxorubicin is an anthracycline antibiotic that is used widely as a chemotherapeutic agent. However, the usefulness of this agent is limited due to its cardiotoxic effects. The mechanisms associated with this cardiotoxicity remain essentially unknown, despite numerous studies describing a range of structural and functional abnormalities. The purpose of the present study was to determine the in vivo and in vitro effects of doxorubicin exposure on sarcoplasmic reticulum (SR) Ca2+-content and contractile protein function. The Ca2+-content of SR is shown to have a biphasic response to in vivo and in vitro doxorubicin exposure that is time- and dose-dependent. In vitro doxorubicin exposure initially reduces the SR Ca2+-content, but the predominant action to block the SR Ca2+-release channel increases SR Ca2+-content within 60 min. Similar results are observed with in vivo doxorubicin exposure: it leads to Ca2+-overload. These data are consistent with the view that doxorubicin acts in a similar manner to ryanodine and results in cardiomyopathy due to Ca2+-overload.

Animals↗
PubMed1998

Attitudes of the physician membership of the society for adolescent medicine toward medical abortions for adolescents.

OBJECTIVE: To document the practices and attitudes of the US physician members of the Society for Adolescent Medicine (SAM) regarding adolescent abortion and contraception, as well as physician willingness to prescribe medical abortion if approved by the Food and Drug Administration (FDA). DESIGN: Cross-sectional questionnaire survey. Participants. The entire physician membership of SAM (N = 1001) was surveyed. A total of 713 physicians responded, with 668 usable surveys yielding an adjusted response rate of 70%. RESULTS: Of the respondents, 81% were trained as pediatricians; 58% had additional adolescent medicine training. Ninety-six percent prescribed contraception for their patients. Sixty-one percent of respondents identified abortion as an option for pregnant adolescents in all circumstances, whereas 4% believed abortion should never be an option. Eighty-nine percent referred their patients for abortions; 90% were aware of medications to induce abortions medically. If these medications (methotrexate and misoprostol, RU-486) were FDA-approved, 42% would prescribe them for their patients; 34% were unsure. Fifty-four percent believed if medical abortions were routinely available, they should be available from primary care physicians. Physicians were significantly more likely to consider prescribing medical abortions if the physician were female, offered postcoital contraception, performed Norplant insertions, referred adolescents for abortions, or performed postabortion medical checkups. Physicians were no more likely to consider prescribing medical abortions according to physician age, specialty training, or date of residency training. Religious affiliation per se was not associated with likelihood of prescribing medical abortions, but Catholic physicians were significantly less likely to consider prescribing medical abortions. CONCLUSIONS: Virtually all SAM physician respondents (96%) reported that abortion for pregnant adolescents should be available under some circumstances. Forty-two percent would prescribe medical abortion if the medications were FDA-approved, suggesting that medical abortion would potentially be available to adolescents from a larger group of physicians than is currently available.

Abortifacient Agents↗
PubMed1998

Production of bovine alpha-lactalbumin in the milk of transgenic pigs.

High production of milk and its components are necessary to allow maximal growth of developing pigs. In this study, transgenic pigs were produced containing the alpha-lactalbumin gene, whose product is a potential limiting component in the production of milk. Two lines of transgenic pigs were produced to analyze the effects that overproduction of the milk protein alpha-lactalbumin may have on milk production and piglet growth. Transgenic pigs were produced through microinjection of the bovine alpha-lactalbumin gene. The gene construct contained 2.0 kb of 5' flanking region, the 2.0 kb coding region, and 329 bp of 3' flanking region. Sows hemizygous for the transgene produced as much as .9 g of bovine alpha-lactalbumin per liter of pig milk. The production of the bovine protein caused approximately a 50% increase in the total alpha-lactalbumin concentration of pig milk throughout a lactation. The concentration of bovine alpha-lactalbumin was highest on d 0 and 5 of lactation and decreased as lactation progressed. The ratio of bovine to porcine alpha-lactalbumin changed during the sow's lactation. This ratio was 4.3 to 1 on d 0 of lactation, but by d 20 of lactation the ratio was .43 to 1. This suggested that the bovine transgene and the endogenous porcine gene are under slightly different control mechanisms. The higher level of total alpha-lactalbumin present on d 0 of lactation was correlated with higher lactose percentage on d 0 in transgenic sows (3.8%), compared with controls (2.6%) (P < .01). Although there was also a trend for higher lactose percentage in transgenic sows on d 5 and 10 of lactation, no significant differences were observed. These data suggest that alpha-lactalbumin is limiting early in lactation of swine. Furthermore, higher concentrations of alpha-lactalbumin early in lactation may boost milk output.

Animals↗
PubMed1998

Psychological characteristics of candidates for liver transplantation.

This study examined depression, anxiety, coping styles, optimism, selected personality characteristics, and perception of family environment among candidates for liver transplantation (OLTX); the goal was to measure and empirically describe psychosocial factors reported to impact on the experience and outcome of transplantation. Subjects were 73 US military veterans being considered for OLTX at the VAMC-Pittsburgh (UD) from 1994 to 1996. Psychological evaluation consisted of chart review, consultation with the transplant team, clinical interview and administration of published, standardized, and readily available psychological tests. Candidates displayed above normal levels of situational anxiety and depression, mainly adaptive coping styles, mild optimism, and positive family environments. Factor analysis of the data identified two dimensions of psychological distress, five coping styles, and three types of family environment. The composite MMPI-2 profile for the sample shows marked elevations of the neurotic triad and moderate elevations of psychasthenia and schizophrenia scales. Psychological distress, psychopathology, coping styles, optimism, and perceptions of family environment correlate with each other in the directions suggested by the literature. These findings support previous research with empirical data; results encourage the development of consistent psychological protocols and procedures to evaluate and treat organ transplant candidates.

Adaptation, Psychological↗
PubMed1997

Monoclonal remyelination-promoting natural autoantibody SCH 94.03: pharmacokinetics and in vivo targets within demyelinated spinal cord in a mouse model of multiple sclerosis.

Chronic inflammatory demyelination of the central nervous system is usually incompletely repaired. However, we previously reported that in vivo treatment with monoclonal antibody SCH 94.03 (produced using spinal cord homogenate as an immunogen) increased myelin repair 4-fold in the Theiler's virus mouse model of chronic progressive multiple sclerosis (Miller et al., 1994; J. Neurosci. 14: 6230-6238). A major issue regarding site and mechanism of action of this antibody is whether SCH 94.03 enters demyelinated CNS lesions and reacts with oligodendrocytes and myelin. To address this question, we radiolabeled SCH 94.03 and studied its distribution into tissues, pharmacokinetics, and binding to cells within demyelinating spinal cord lesions in vivo. SCH 94.03 distributed widely into extracellular water following intraperitoneal injection and was eliminated with a terminal half-life of 3-4.5 days. Only a portion of the total dose (0.4%) entered brain and spinal cord. SCH 94.03 accumulated 1.5-2.0-fold in brain between 1 and 7 days after injection, but its pharmacokinetics were otherwise similar to those of an isotype control IgMkappa antibody. Oligodendrocytes, myelin sheaths and, less frequently, axons were labeled within demyelinating lesions as detected by light and electron microscopic autoradiography. These findings suggest that remyelination-promoting autoantibodies could act within the demyelinating lesion of the central nervous system by binding to the oligodendrocyte, myelin, or axon.

Animals↗