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Biomedical subjects

J Miller

Publications and source records attributed to J Miller.

At least 775 records · Page 43Linked to original sources
PubMed1988

Ureteral leak around an aortic bifurcation graft: complication of ureteral stenting.

Aortoiliac bypass surgery has a 2 to 20 per cent incidence of ureteral injury causing postoperative hydronephrosis frequently without symptoms. We describe a patient in whom a ureteral stricture developed 12 days after placement of an aortic bifurcation graft. Treatment consisted of ureteral dilation and stenting following which a ureteral leak developed around the bifurcation graft from the stented dilation site, presumably from pressure necrosis of the ureter caught between the pulsating graft and the ureteral stent. The patient did well with external nephrostomy drainage. We conclude that ureteral stenting of patients suffering from significant aortoiliac disease should be approached with great caution, using the softest stent material available.

Aged↗
PubMed1988

Components of the location probability effect in visual search tasks.

In visual search tasks, targets are detected more rapidly when they appear in locations that commonly contain a target than when they appear in locations that rarely contain a target. Five experiments were conducted to investigate two specific properties of this location probability effect: its dependence on spatial location versus relative position and its dependence on or independence of target identity. In Experiment 1 spatial location of a stimulus row was varied to determine whether high location probability facilitates target detection in a particular location in visual space or a particular relative position within the row. Both were facilitated to approximately the same extent. In Experiment 2 an inducing target occurred with high probability in one of four display locations, and a test target occurred with equal probability in all four locations. Both targets were found more quickly in the high-probability location than in the other locations, but the advantage associated with targets in the high-probability location was larger for the inducing target than for the test target. In Experiments 3-5 the correspondence between the components observed in Experiments 1 and 2 was examined. The overall pattern of results was compatible with a model in which the location probability effect is produced partly by an attentional spotlight, which facilitates processing of any stimulus appearing in a particular location in visual space, and partly by a network of position-specific letter detectors, which facilitates detection of a particular letter in a particular relative position within a display. Models with flexible scanning strategies were also considered.

Attention↗
PubMed1988

A warning about median reaction time.

When used with positively skewed reaction time distributions, sample medians tend to over-estimate population medians. The extent of overestimation is related directly to the amount of skew in the reaction time distributions and inversely to the size of the sample over which the median is computed. Simulations indicate that overestimation could approach 50 ms with small samples and highly skewed distributions. An important practical consequence of the bias in median reaction time is that sample medians must not be used to compare reaction times across experimental conditions when there are unequal numbers of trials in the conditions. If medians are used with unequal sample sizes, then the bias may produce an artifactual difference in conditions or conceal a true difference. Some recent studies of cuing and stimulus probability effects provide examples of this potential artifact.

Computer Simulation↗
PubMed1988

Identification of the glycosaminoglycan-attachment site of mouse invariant-chain proteoglycan core protein by site-directed mutagenesis.

The invariant chain (Ii), a nonpolymorphic glycoprotein that associates with the immunoregulatory Ia proteins encoded by the major histocompatibility complex, has a proteoglycan form (Ii-CS) that bears a chondroitin sulfate glycosaminoglycan. In this proteoglycan form, Ii may remain associated with Ia at the cell surface. Inhibitors that prevent the addition of glycosaminoglycan to Ii have been found to depress antigen-presenting function. Ii does not have multiple candidate glycosaminoglycan-attachment sites, and we used site-directed mutagenesis to replace a candidate serine glycosaminoglycan-acceptor site with alanine at position 201 in the murine Ii protein. Transfection of the normal or altered gene into Ii-negative COS-7 cells showed that equivalent amounts of core Ii protein and its acidic, terminally glycosylated forms were synthesized, but the Ala-201 mutant Ii did not give rise to Ii-CS. The mutant protein had apparently normal transport through the Golgi compartment and associated stably with Ia molecules. Thus, this mutation directly identifies the site of glycosaminoglycan addition and shows that it can be eliminated without adversely affecting the overall biosynthesis of Ii.

Antigens, Differentiation, B-Lymphocyte↗
PubMed1988

A rapid, enzymatic method for the determination of chloramphenicol in serum.

A simple, rapid assay of serum chloramphenicol has been developed which combines the specificity of the enzyme chloramphenicol acetyltransferase with the convenience of a colorimetric detection system. The assay is linear over the drug concentration range 5-200 microM (1.5-65 mg/l) and therefore is suitable for detection below and above the therapeutic range (31-62 microM, 10-20 mg/l with potential toxicity above 75 microM, 24 mg/l). This method does not detect the microbiologically inactive succinate or palmitate pro-drugs of chloramphenicol and evidence suggests that the major metabolite, chloramphenicol glucuronide also is not detected. Good correlation with an HPLC method has been achieved (r = 0.9860). The assay is based on a two reagent system with very simple methodology, the only instrumentation required being a spectrophotometer. However, the assay could be adapted to run on a range of discrete analysers.

Bilirubin↗
PubMed1988

Effects of in vitro and in vivo anticanine T lymphocyte and anticanine class II-specific monoclonal antibodies in the beagle.

Two murine anticanine lymphocyte monoclonal antibodies, designated T83 and B1F6, were assessed for (1) in vitro antiepitope activity to circulating lymphocyte subsets, their functional effects on lymphoproliferative assays and binding specificities to diverse cell suspensions and tissue sections; (2) in vivo effects after administration on cells expressing the target epitopes, lymphoproliferation, and allograft survival; and (3) the host immune response to the injected murine immunoglobulins. The monoclonal antibody T83 (IgG3) appeared to be specific for a T cell subset with an up-regulating function on lymphoproliferation. It caused a profound depletion of cells with the appropriate epitope after intravenous administration but it bound to lymphocyte membrane epitopes on some cells in peripheral blood that did not become depleted and putatively caused other modulating effects on lymphocyte function. The monoclonal antibody B1F6 (IgG2a, previously described) was immunologically specific in vitro for cells expressing class II major histocompatibility complex antigens. In the dog, this also consisted of 50% of T lymphocytes. After intravenous administration, there were functional effects similar to those of T83. A modest prolongation of survival of renal allografts was observed when both mAbs were used as the sole immunosuppressive agent. These studies also demonstrated the occurrence of natural canine antimurine IgG antibodies. Administration of either monoclonal antibody was followed by a rapid increase in the concentration of the antimouse antibody(s). We postulate that the presence of canine natural antimouse IgG markedly influenced the biologic effects of in vivo administered monoclonals.

Animals↗
PubMed1988

A follow-up study on alcoholics with and without co-existing affective disorder.

Three-hundred male alcoholics were selected from consecutive admissions to hospital. They were divided into three diagnostic sub-groups: primary alcoholics; alcoholics with unipolar affective disorder; and alcoholics with bipolar affective disorder. After three follow-up interviews over a 2-year period after hospital discharge, the three sub-groups reported differences in frequency of mood change, amount of treatment received, and hospital attendance, although there were no clear-cut differences in items associated with their alcoholism. There were, however, some indications that bipolar patients functioned at a better level during the follow-up period, particularly those who were older, had a previous history of longer periods of abstinence, and maintained more frequent contact with Alcoholics Anonymous (AA) and their family doctor.

Adolescent↗
PubMed1988

The acute geriatric psychiatry service: a suggested model.

In general hospitals, especially on acute medical-surgical, and general psychiatric units, geriatric patients are often exposed to attitudes of resentment or rejection. Individuals with treatable mental illnesses may be relatively neglected or dismissed as "senile," and their special needs not attended to. This tends to occur when the particular psychological issues of elderly patients are not shared by most of the other patients, and also when staff members are prejudiced about old people, either because of fear about their own aging or because of unresolved difficulties with parents or grandparents. The authors believe that age-specific geriatric units are the most effective treatment format for the elderly in need of psychiatric care. One example of such a unit opened in 1980, the Geriatric Psychiatry Unit currently in operation at the Johnston R. Bowman Health Center for the Elderly, a part of Rush-Presbyterian-St. Luke's Medical Center in Chicago, is described.

Aged↗
PubMed1988

Leukotriene D4 receptor-mediated hydrolysis of phosphoinositide and mobilization of calcium in sheep tracheal smooth muscle cells.

A sheep tracheal smooth muscle primary culture cell system was developed to characterize leukotriene D4 (LTD4) receptor-mediated biochemical and pharmacological effects. [3H]LTD4 binding to the enriched plasma membrane receptor was specific, stereoselective and saturable. LTE4 and high affinity receptor antagonists bound to the receptors with a rank-order potency that was expected from previous smooth muscle contraction studies. In the [3H]myoinositol labeled cells, LTD4 and LTE4 induced phosphoinositide hydrolysis. The biosynthesis of [3H]inositol-trisphosphate was rapid and the induction of biosynthesis of [3H]inositol-monophosphate by LTs was stereoselective and specific and was inhibited specifically by a receptor antagonist, SKF 104353. In the fura-2 loaded smooth muscle cells, LTD4 and LTE4 induced transient intracellular Ca++ mobilization. The fura-2/Ca++ transient was stereoselective and specific and was inhibited by receptor antagonist, SKF 104353. These results suggest that the cultured sheep tracheal smooth muscle cells have plasma membrane receptors for LTD4. These receptors were coupled to a phospholipase C that, when activated by agonists, induced hydrolysis of inositol containing phospholipids. The hydrolysis products, e.g. diacylglycerol and inositol-trisphosphate, may serve as intracellular messengers that trigger or contribute to the contractile effect in sheep tracheal smooth muscle.

Animals↗
PubMed1988

Contribution of monocyte-macrophage system to serum alpha 1-antitrypsin.

The major serum antiprotease is alpha 1-antitrypsin (A1AT). Deficiency of A1AT can result in infantile cirrhosis and premature emphysema, both of which have a high degree of morbidity and significant mortality. Although synthesized primarily by the liver, A1AT has been histochemically localized in monocytes and macrophages in vitro and has been shown to be produced in tissue culture of monocyte-macrophage origin. This study was planned to quantitatively and qualitatively assess the in vivo monocyte-macrophage system contribution to serum A1AT. We used bone marrow transplantation (BMT) as an experimental method because there is commanding evidence that after engraftment, the monocyte-macrophage system of the recipient is replaced by that of donor origin. Protease inhibitor (Pi) typing was done on 150 potential BMT recipients and on their potential donors before transplantation. From these initial recipients, 92 eventually underwent transplantation, and 11 recipient-donor pairs, in which each donor's Pi type contained a band not in the recipient's Pi type, were chosen for the study. Six recipients survived beyond 100 days after BMT, and in these cases the donor contained either an S or an M2 band in his or her Pi type not present in the recipient. Using a silver stain method on diluted serum of known M1M2 and MS types, we were able to detect a 2% dilution of the S band and a 25% dilution of the M2 band. When the same method was applied to gels used in typing recipient Pi after BMT, we were unable to detect any contribution to serum A1AT by the donor monocyte-macrophage system.

Bone Marrow Transplantation↗
PubMed1988

Inhibition of the intraerythrocytic development of Plasmodium falciparum in glucose-6-phosphate dehydrogenase deficient erythrocytes is enhanced by oxidants and by crisis form factor.

In this study, we have examined P. falciparum development in untreated normal or G6PD deficient erythrocytes as well as in parasitized cells exposed to isouramil--a fava bean extract known to induce oxidant stress in G6PD deficient erythrocytes (a condition known as favism), to diamide--a thiol oxidizing agent and to crisis form factor (CFF)--a non-immunoglobulin product found in the sera of man immune to malaria. We observed a significant retardation in intraerythrocytic development of parasites cultured in the G6PD deficient cells in comparison with parasites grown in the normal ones. Plasmodia within the G6PD deficient erythrocytes were markedly more sensitive to the inhibitory activity of CFF or the oxidizing agents diamide and isouramil. Mature stages of the parasites in both normal and G6PD deficient erythrocytes were more vulnerable than young ring forms, to oxidizing agents. The overall results show that the genetic trait of the host cell and the degree of maturation of the plasmodia are both crucial factors in determining the sensitivity of the parasite to oxidant stress.

Animals↗
PubMed1988

The effect of postoperative collateral ligament laxity in total knee arthroplasty.

Forty-seven patients who had been treated by 63 total knee arthroplasties were assessed at 12-84 months after the operation. The data were analyzed to determine if collateral ligament laxity had a detrimental effect on the clinical outcome. The Hospital for Special Surgery (HSS) score was used to make the clinical assessment and a modified HSS score, which excluded points awarded for laxity, was also used. Unidirectional (varus or valgus) and total (varus and valgus) laxity were used as a basis of analysis. None of the examined parameters produced results suggesting that lax knees were worse than stable knees. Indeed, knees with increasing laxity through the categories of mild and moderate showed better statistically significant results in HSS score and pain than those with lesser degrees of laxity. Seventy-five percent of the knees with unidirectional laxity were classified as excellent; only 38.5% of the stable knees were graded as excellent (p less than 0.01). Only 9% of the lax knees had complaints of pain; 38% of the stable knees were painful (p less than 0.05). No significant difference in functional score and walking ability was noted between the lax and the stable knees. Seventy-eight percent of the lax knees had a range of motion over 100 degrees; 62.5% of the stable knees achieved this range.

Adult↗