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Biomedical subjects

M Rogers

Publications and source records attributed to M Rogers.

At least 19 recordsLinked to original sources
PubMed1992

Phospholipase activation during monocyte adherence and spreading.

Phospholipase activation is an important element in cellular signal transduction. In our study we investigated the role and regulation of phospholipase activation during human monocyte adherence and spreading. In human monocytes, phospholipase inhibition (with bromophenacyl bromide (BPB) or manoalide) impaired cell adherence and spreading. In contrast, neither cyclooxygenase/lipoxygenase inhibition nor platelet activating factor receptor blockade affected these responses. The impaired adherence and spreading induced by phospholipase inhibition with BPB could be partially reversed by the addition of nM levels of arachidonate (20:4(n - 6)). Dihomogammalinolenic acid (20:3(n - 6)) could substitute for arachidonate, but other polyunsaturated fatty acids were ineffective in this regard. The phospholipase inhibitor, BPB was selective in its effects on cellular phospholipase activities. BPB inhibited adherence/spreading-related and PMA-stimulated phospholipase activities, but not Ca2+ ionophore-stimulated phospholipase activity. To further probe for the role of Ca2+ in monocyte adherence and spreading, monocytes were loaded with MAPTAM (bis-(2-amino-5-methylphenoxy)-ethane-N,N,N',N', tetraacetic acid tetraacetoxymethyl ester), an EGTA analog. In contrast to phospholipase inhibition, intracellular Ca2+ chelation with MAPTAM did not affect monocyte adherence but did inhibit monocyte spreading. MAPTAM partially inhibited adherence/spreading-stimulated phospholipase activity, but did not inhibit PMA-stimulated phospholipase activity. These data suggest that human monocyte adherence and spreading may sequentially activate Ca(2+)-independent and then Ca(2+)-dependent phospholipases to release arachidonate. The activation of phospholipase and the release of arachidonate appear to be integral parts of the adhesion process.

Acetophenones↗
PubMed1992

A program model to enhance adherence in work-site-based fitness programs.

We describe a program model designed to achieve high adherence, a major problem for work-site exercise/fitness programs. Our model is a 6-month program consisting of 15 1-hour program meetings, with participants exercising on their own time four times per week. Procedures employed to enhance adherence are contracting, group competition, monitoring, and social support. This program model has been applied nine times. One hundred fifty-nine university employees took part in the initial test with a dropout rate of 9% (15 persons). The average adherence rate for nondropouts was 98%, which is higher than rates usually reported in the literature. Adherence was defined as exercising four times a week.

Adult↗
PubMed1992

Cardiofaciocutaneous syndrome.

A boy aged 6 years 10 months with dysmorphic features of the cardiofaciocutaneous syndrome is reported. This patient had early total alopecia, persistent hypotrichosis and an inflammatory hyperkeratotic dermatosis with psoriasiform features occurring predominantly on the scalp, extensor surfaces of limbs and trunk. Bilateral progressive femoral valgus deformity culminated in unilateral hip subluxation. Previously undescribed neuro-ophthalmologic findings are reported.

Abnormalities, Multiple↗
PubMed1992

Pityriasis lichenoides and lymphomatoid papulosis.

The clinical features, histopathology, immunopathology, and management of pityriasis lichenoides and lymphomatoid papulosis are discussed, with particular emphasis on the pediatric aspects of these conditions. The difficulties in logically separating pityriasis lichenoides into an acute (pityriasis lichenoides et varioliformis acuta) and a chronic (pityriasis lichenoides chronical) form are addressed. The development of lymphoreticular malignancy in patients with lymphomatoid papulosis has been well documented, but pityriasis lichenoides has characteristically been regarded as a benign condition. However, recent reports of the development of large plaque parapsoriasis in patients with pityriasis lichenoides have led to a reconsideration. Some of these patients were in the pediatric age group. Although there are significant clinical, histopathological, and immunopathological differences between pityriasis lichenoides and lymphomatoid papulosis, the demonstration of similar clonal T cell receptor gene rearrangements and the confirmation of the potentially premalignant nature of both suggests that there may indeed be an interrelationship between these two controversial entities. Close follow-up of patients with both of these conditions is recommended, with observation being discontinued only when the patient has been free of lesions for several years.

Child↗
PubMed1991

A preliminary evaluation of 566C80 for the treatment of Pneumocystis pneumonia in patients with the acquired immunodeficiency syndrome.

BACKGROUND: The drug 566C80 is an investigational hydroxynaphthoquinone that is active against Pneumocystis carinii in vitro and in animal models. Initial studies in humans indicate that 566C80 is safe and has adequate bioavailability after oral administration. METHODS: We conducted an open-label trial of 566C80 in 34 adults with the acquired immunodeficiency syndrome (AIDS) and untreated pneumocystis pneumonia. All the patients had a partial pressure of arterial oxygen of at least 60 mm Hg while breathing room air. They were enrolled sequentially in three cohorts taking 566C80 at different dosages, all administered orally: 750 mg three times daily for 5 days, then twice daily for 16 days; 750 mg three times daily for 21 days; and 750 mg four times daily for 21 days. RESULTS: All 34 patients survived, and 27 (79 percent) were successfully treated with 566C80 alone. The mean partial pressure of oxygen in 33 patients was 78 mm Hg at entry and 93 mm Hg after the course of 566C80 (P less than 0.001). In five patients (15 percent) the drug was discontinued because of lack of response. In four patients (12 percent), the drug was discontinued because of toxicity (fever and rash in two patients each). In two of these, treatment was considered to have succeeded because 566C80 was not discontinued because of toxicity until after day 14. Five of the successfully treated patients had rashes that resolved despite continued therapy. In nine patients, serum alanine aminotransferase levels rose above 100 U per liter. During the first three months after the completion of therapy, pneumocystis pneumonia recurred in 4 of the 27 successfully treated patients, and another 3 patients had recurrences between month 3 and month 6 of follow-up. The mean (+/- SEM) steady-state plasma levels of 566C80 were similar in the three cohorts: 16.3 +/- 2.10, 20.4 +/- 2.48, and 18.9 +/- 3.08 micrograms per milliliter in the patients taking the drug twice daily, three times daily, and four times daily, respectively. CONCLUSIONS: From these preliminary data, the investigational compound 566C80 appears to be a safe, effective, and well-tolerated therapy for P. carinii pneumonia of mild-to-moderate severity in patients with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Epitope mapping of the Syrian hamster prion protein utilizing chimeric and mutant genes in a vaccinia virus expression system.

The cellular prion protein (PrPc) is a host-encoded sialoglycoprotein bound to the external surface of the cell membrane by a glycosyl phosphatidylinositol anchor. A posttranslationally modified PrP isoform (PrPSc) is a component of the infectious particle causing scrapie and the other prion diseases. mAb have been raised against the protease-resistant core of Syrian hamster (SHa) PrPSc designated PrP 27-30. To map the epitopes within PrP reacting to these antibodies, we have expressed wild-type, chimeric mouse (Mo)/SHa and mutant MoPrP genes using recombinant vaccinia virus systems. The fidelity of the expression of recombinant PrPC was examined using vaccinia viruses expressing SHa-PrPC. It is full length, possesses Asn-linked carbohydrates and is attached to the external surface of the cell membrane by a glycosyl phosphatidylinositol anchor that is sensitive to cleavage by phosphatidylinositol-specific phospholipase C. We have tested 18 mAb for their ability to bind to chimeric prion proteins on immunoblots. Three distinct epitopes were identified that mapped to amino acid differences between SHa and MoPrP sequences. The first epitope, recognized by three of the antibodies tested, was defined by methionines at amino acids 108 and 111 in the mouse protein. The second epitope was dependent upon the presence of asparagines at positions 154 and 174 in MoPrP and was recognized by four of the antibodies tested. The third epitope mapped to a single amino acid substitution at residue 138 in MoPrP. mAb raised against SHaPrP 27-30 specific for this epitope are able to bind MoPrPC which has a single amino acid change (Ile to Met) at position 138. Eleven of the 18 antibodies tested mapped to this immunodominant epitope. It is located within a postulated amphipathic helix, a structure associated with immunodominant Ag. Inasmuch as PrPC, in its native form on the cell surface, is detected by the mAb 13A5 (a prototypic antibody of the immunodominant third epitope class), it is likely that this epitope is accessible in the native conformation of this protein.

Animals↗
PubMed1991

Treatment of macrophages with oxidized low-density lipoprotein increases their intracellular glutathione content.

Macrophages derived from the human monocyte cell line THP-1 or isolated from the peritoneum of C3H/HEJ mice were incubated with oxidized low-density lipoprotein (LDL) and the total glutathione content (oxidized plus reduced) was measured. An initial depletion of glutathione was followed by an increase, such that after a period of 24 h the glutathione content has approximately doubled. This response required the oxidation of the lipid phase of the LDL molecule, since both native LDL and acetylated LDL had little effect on glutathione levels. The response of the cells to oxidized LDL was dependent on the extent of oxidative modification of the protein. It was also found that 4-hydroxynonenal had a similar effect on THP-1 cells, and we suggest that this or other aldehydes present in oxidized LDL causes the induction of glutathione synthesis in response to an initial oxidative stress and consequent glutathione depletion. In addition, we found that both cell types possess transferases and peroxidases capable of detoxifying aldehydes and peroxides. However, treatment of cells with oxidized LDL or 4-hydroxynonenal for a period of 24 h had no effect on the activities of these enzymes.

Aldehydes↗
PubMed1991

Essential fatty acid deficiency impairs macrophage spreading and adherence. Role of arachidonate in cell adhesion.

Dietary polyunsaturated fatty acid manipulation exerts a strikingly protective effect in models of tissue inflammation and injury. A critical element of this effect appears to revolve around leukocyte trafficking but underlying mechanisms are ill understood. In the current study it was observed that essential fatty acid (EFA) deficiency markedly impaired the capacity of resident macrophages to spread and adhere. This effect was not a simple function of the alteration of membrane fatty acid composition. Elicited EFA-deficient macrophages were equally adherent to elicited control cells, despite the fact that they were equally EFA-deficient relative to resident EFA-deficient cells. With respect to the mechanism underlying defective macrophage adherence in EFA deficiency, no change in the expression of cell surface adherence molecules (Fc receptor, Mac-1, or LFA-1) was noted with the deficiency state. Also, an adherence defect could not be induced in normal cells pharmacologically with cyclooxygenase blockade, lipoxygenase blockade, or a platelet-activating factor receptor antagonist. In contrast, phospholipase inhibition was able to induce a spreading and adherence defect in resident macrophages similar to that seen with EFA deficiency. Using several phospholipase inhibitors, a correlation between phospholipase inhibition and impairment of adherence was observed. Adding back exogenous fatty acids to cells after phospholipase inhibition demonstrated that normal adherence was reconstituted with arachidonate. This alteration in macrophage spreading and adherence with EFA deficiency may be an important component of the anti-inflammatory effect of dietary polyunsaturated fatty acid manipulation. Additionally, these results suggest that arachidonate may be an intracellular mediator of leukocyte adherence.

Animals↗
PubMed1991

Prenatal records: a national survey of content.

The uses of prenatal records extend well beyond management of patient care. They are also vehicles for communication, quality assurance, financial compensation, and legal documentation. To serve each of these functions, records should be systematic and detailed. This nationwide study was conducted to assess the extent to which prenatal records in current use include sufficient detail to serve these functions. A random sample of 2746 physicians who listed obstetrics and gynecology, obstetrics, or maternal-fetal medicine as a primary or secondary specialty in the American Medical Association file were contacted by mail and were requested to submit a blank copy of their prenatal records. The records of 969 respondents were examined for the presence or absence of 53 items that corresponded to the five functions identified above. The items of interest were present in 1% to 98% of the records. More than 90% included items of traditional medical-obstetric significance. The percentages of records with items of more contemporary relevance (e.g., cigarette smoking, risk-assessment checklists, psychological stress) were found in lower percentages of the records. Stratified and logistic regression analyses revealed that the most systematic and detailed records were commercially available, were used by physicians in hospital and government program-based practices, and were used by physicians who had completed medical school less than or equal to 15 years before the survey. The findings suggest that physicians who do not use commercially available forms or those who are in private or health maintenance organization practice or have been practicing for more than 15 years should reconsider their prenatal records in light of the functions they will serve in the 1990s and beyond.

Communication↗
PubMed1991

Acoustic reflectometry for airway measurement. Principles, limitations and previous work.

Acoustic pulse reflectometry is a relatively recent technique which allows the non-invasive measurement of human airways. The technique consists of guiding an acoustic impulse through the subject's mouth and into the airway. Suitable analysis of the resulting reflection (the 'echo') allows a reconstruction of the area-distance function. The non-invasive nature of the technique offers significant advantages over the established methods of x-ray cephalometry and CT scanning, and makes it very attractive for the investigation of ENT problems and sleep apnoea, and in the anaesthetic management of patients. This paper describes the theory and limitations of acoustic reflectometry, discusses previous work, and suggests some modifications: it is currently being implemented clinically.

Acoustics↗
PubMed1991

Lack of correlation between maternal antibodies to V3 loop peptides of gp120 and perinatal HIV-1 transmission. The NYC Perinatal HIV Transmission Collaborative Study.

Recent reports have suggested that maternal antibodies to specific epitopes of the variable region 3 (V3 loop) of gp120 of HIV-1 might protect against perinatal transmission. In an attempt to confirm these findings, sera from 34 HIV-1-seropositive mothers, representing 13 episodes of mother-to-infant transmission and 23 episodes of non-transmission (two mothers had two pregnancies each during the study period), were tested for the presence of antibodies to various regions of the gp120 V3 loop. Synthetic peptides were generated from HIV-1MN. Of the four peptides tested by enzyme-linked immunosorbent assay (ELISA), only antibody to the C53 peptide (Env310-322, principal neutralizing determinant) was present in maternal sera. Antibody to the C53 sequence was present in 11 specimens from transmitting mothers and 21 from non-transmitting mothers (84.6 and 91.3%, respectively, P = 0.6). No reactivity was detected against the C51, C57, or C58 peptide sequences, located on the sides of the V3 loop. In an antigen-limited ELISA, only two specimens from transmitting mothers and two specimens from non-transmitting mothers had detectable 'high-affinity' antibodies to C53 at low antigen concentrations (15.4 and 8.7%, respectively; P = 0.6). Our results do not support previous reports that epitope-specific antibodies to the V3 loop peptides protect against perinatal transmission. Further research is required to determine whether any specific maternal humoral response might influence HIV-1 perinatal transmission.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Naproxen induced pseudoporphyria in juvenile chronic arthritis.

We report 6 cases of porphyria-like skin reactions in children taking naproxen for juvenile chronic arthritis. The lesions mimicked either erythropoietic protoporphyria or porphyria cutanea tarda, with both forms occurring in 2 patients. Biochemical studies excluded abnormal porphyrin metabolism.

Adolescent↗