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Biomedical subjects

K Anderson

Publications and source records attributed to K Anderson.

At least 325 records · Page 18Linked to original sources
PubMed1988

Silent myocardial ischemia in asymptomatic survivors of unrecognized myocardial infarction and matched controls.

Although silent myocardial ischemia (SI) occurs frequently in patients with angina and is of prognostic significance, little is known of its occurrence in other subgroups. We assessed the incidence of SI in offspring of Framingham Heart Study (FHS) patients following unrecognized myocardial infarction (UMI) and in controls without MI but who were matched for age, sex, hypertension, diabetes, smoking, and total cholesterol at entry into the FHS. Of the 20 UMI patients, six had died and one with left bundle branch block was excluded. The remaining 13 UMI patients and 26 control patients underwent 24-hour ambulatory electrocardiographic monitoring (AECG) for SI. Two patients (one from each group) with angina were excluded from the AECG analysis. Only two (15.4%) of the UMI patients and two (7.7%) of the control patients had any AECG evidence of SI. These preliminary results suggest that routine monitoring for SI is not indicated in asymptomatic long-term survivors of UMI or in asymptomatic patients without prior MI but with otherwise similar risk profiles.

Adult↗
PubMed1988

Differentiation of U937 cells induced by 5,8,11,14-eicosatetraynoic acid, a competitive inhibitor of arachidonic acid metabolism.

5,8,11,14-Eicosatetraynoic acid, a competitive inhibitor of arachidonic acid metabolism, rapidly and reversibly inhibited DNA synthesis in U937 cells. This inhibition was not due to cytotoxicity, as judged by studies with trypan blue, release of 51Cr-labeled proteins, and its reversibility. When cells were cultured in the presence of ETYA for several days, morphologic, enzymatic, and functional changes consistent with differentiation occurred. Morphologic evidence of differentiation was evident by light microscopy. The cells enlarged, the ratio of cytoplasm to nuclei increased, secretory granules and vacuoles developed, the apparent activity of nonspecific esterase rose, and ingestion of latex particles increased. A morphology consistent with that of an immature monocyte was evident by electron microscopy. These features included the development of lobulated nuclei, a reduced nuclear to cytoplasmic ratio, increased complexity and development of the cytoplasmic components, and the disappearance of fimbriated plasma membrane structures. In addition, putative polyribosomes were less evident. When cells differentiated by ETYA were cultured in media free of the inhibitor, DNA synthesis reinitiated and the cell number increased; differentiation was phenotypic and not genotypic. To examine whether ETYA-induced differentiation was obligatorily related to its suppression of DNA synthesis, cells were incubated in 50 microM hydroxyurea and DNA synthesis was inhibited for 24 to 36 h without morphologic evidence of cellular differentiation. However, addition of ETYA to cells prevented from dividing by hydroxyurea and subsequent culture for 72 h induced morphologic evidence of differentiation. The effects of ETYA on cell division and cell differentiation are closely related but can be dissociated. The molecular events underlying these results remain to be established.

5,8,11,14-Eicosatetraynoic Acid↗
PubMed1988

Massive doses of midazolam infusion for delirium tremens without respiratory depression.

After undergoing replantation and revascularization surgery for a complex hand injury, a 25-yr-old male developed florid delirium tremens. Over a 5-day period, he received 2850 mg of midazolam as a constant infusion of varying rates. The midazolam controlled his severe agitation without respiratory depression and the hand reconstruction survived undamaged.

Adult↗
PubMed1988

Effect of cigarette smoking on the specific antibody response in pigeon fanciers.

Titres of circulating IgG antibodies to pigeon gammaglobulin and end expired carbon monoxide concentrations were measured in 86 pigeon fanciers attending the "Show of the Year." Antibody levels were significantly higher in non-smokers and in those with end expired carbon monoxide concentrations below 10 parts per million.

Alveolitis, Extrinsic Allergic↗
PubMed1988

Temporal and regional variability of collateral resistance response to histamine.

Using the wedged bronchoscope technique, we measured the changes in collateral resistance (Rcoll) in dogs resulting from exposure to aerosols of increasing concentrations of histamine. Histamine dose-response curves were performed in each of two to three separate lobar segments of an individual mongrel dog's lungs. Five dogs were studied. The same segments were reexamined on later occasions (2-11 wk apart) to determine whether the responsiveness to histamine had altered with time. Measurements of base-line Rcoll for a given segment were reproducible (coefficient of variation 0.48). In contrast, we observed that the estimated dose of histamine required to increase Rcoll by 50% (ED150Rcoll) was extremely variable both among lung segments of an individual dog on a single experimental day (geometric mean variability of 40-fold) and for a given segment when reexamined on repeated occasions (geometric mean variability of 47-fold). The ED150Rcoll did not correlate with the base-line Rcoll. The degree of variability we observed suggests that peripheral contractile elements are under the influence of powerful local modulating factors that vary both regionally and temporally.

Airway Resistance↗
PubMed1988

Methacholine-induced bronchoconstriction in dogs: effects of lung volume and O3 exposure.

The maximal effect induced by methacholine (MCh) aerosols on pulmonary resistance (RL), and the effects of altering lung volume and O3 exposure on these induced changes in RL, was studied in five anesthetized and paralyzed dogs. RL was measured at functional residual capacity (FRC), and lung volumes above and below FRC, after exposure to MCh aerosols generated from solutions of 0.1-300 mg MCh/ml. The relative site of response was examined by magnifying parenchymal [RL with large tidal volume (VT) at fast frequency (RLLS)] or airway effects [RL with small VT at fast frequency (RLSF)]. Measurements were performed on dogs before and after 2 h of exposure to 3 ppm O3. MCh concentration-response curves for both RLLS and RLSF were sigmoid shaped. Alterations in mean lung volume did not alter RLLS; however, RLSF was larger below FRC than at higher lung volumes. Although O3 exposure resulted in small leftward shifts of the concentration-response curve for RLLS, the airway dominated index of RL (RLSF) was not altered by O3 exposure, nor was the maximal response using either index of RL. These data suggest O3 exposure does not affect MCh responses in conducting airways; rather, it affects responses of peripheral contractile elements to MCh, without changing their maximal response.

Airway Resistance↗
PubMed1988

Herd composite somatic cell counts: average linear score and weighted average somatic cell count score and milk production.

The relationship between herd production weighted average somatic cell count (average of somatic cell count weighted by individual cow milk production) and average linear score (average of individual cow linear score somatic cell counts) was investigated using three models. The model with the highest R2 was log weighted average somatic cell count versus average linear score. Use of the regression model results to convert an average linear score to weighted average somatic cell count results in a bulk tank somatic cell count approximately twice that of conversion of a linear score somatic cell count when done on an individual cow basis. Rolling herd average milk decreased 190 kg as average linear score increased by 1.

Animals↗
PubMed1988

B protein of factor XIII: differentiation between free B and complexed B.

Plasma factor XIII is a complex of A and B proteins noncovalently linked in a tetramer, A2B2, Enzyme-linked immunosorbent assays (ELISA) were developed to measure the separate factor XIII proteins and the complex. All of the A protein in plasma is in the zymogen complex. The B assay measures the total amount of B protein in plasma (both free B and complexed B). This was confirmed by nondenaturing gel electrophoresis and immunoblotting, which showed two bands for B in plasma with this antibody. Two assays were developed to measure A2B2 complex specifically. One assay used a monoclonal antibody to B to bind antigen and measured B protein in the zymogen complex only and hence the concentration of the complex. The specificity of this antibody was also shown by immunoblotting. In the second assay, the capture antibody was to B and the tag antibody was to A. These two assays gave identical results for the concentration of A2B2 (0.07 mumol/L, 21.6 micrograms/mL in normal plasma). Thus, for the first time, differentiation and quantitation of free B and complexed B in plasma was possible. The assays were used to measure factor XIII proteins in plasma from normal controls, homozygous-deficient factor XIII patients, and their heterozygous relatives. The normal concentration of A in plasma is 0.13 to 0.16 mumol/L (approximately 11 micrograms/mL), all of which is in A2B2. The total B concentration is 0.26 to 0.28 mumol/L (approximately 21 micrograms/mL), half of which is complexed. The free B concentration is 0.13 mumol/L (approximately 10 micrograms/mL). Homozygous-deficient patients have essentially no A protein, but their free B concentration is 0.11 mumol/L. Heterozygotes have decreased A2B2, but their free B is 0.11 mumol/L. These results indicate that the concentration of free B is remarkably constant and does not depend on the concentration of A2 or A2B2.

Antibodies, Monoclonal↗
PubMed1988

Quantitative estrogen and progesterone receptor levels related to progression-free interval in advanced breast cancer patients treated with megestrol acetate or tamoxifen.

Estrogen receptor (ER) and progesterone receptor (PgR) levels have been reported to have prognostic significance with respect to disease-free survival in early-stage breast cancer patients. The current retrospective study was undertaken to determine whether ER and PgR levels, as well as other potential prognostic factors, might be related to a progression-free interval (PFI) during additive hormonal therapy in advanced-stage breast cancer patients. Eligibility requirements for this study included the following: histologically confirmed recurrent or metastatic breast cancer, known quantitative ER and PgR levels, postmenopausal status, treatment with either megestrol acetate or tamoxifen, and Eastern Cooperative Oncology Group (ECOG) performance status less than or equal to 2. The characteristics of the 105 patients included in these analyses were as follows: median age, 62 years; median disease-free interval (DFI), 523 days; median ER level, 44 fmol/mg; median PgR level, 52 fmol/mg; soft tissue-dominant disease, 37 patients (35%); bone-dominant disease, 36 patients (34%); visceral-dominant disease, 32 patients (31%); one site of disease, 60 patients (58%); two or more sites of disease, 45 patients (42%); treatment with megestrol acetate, 62 patients (59%); treatment with tamoxifen, 43 patients (41%). All of the independent variables listed immediately above were included in a multiple linear regression analysis in which PFI, expressed as log PFI, was the dependent variable. In this analysis, a positive linear relationship was observed between log PFI and the following independent variables: log ER, log PgR, and age (r2 = 0.329). An alternative model (r2 = 0.350) was derived, in which previous treatment with chemotherapy was negatively related to log PFI. However, it appears that previous treatment with chemotherapy could be a "proxy variable," because patients who had been treated with chemotherapy previously were significantly younger and had significantly lower ER (P = 0.0001) and PgR levels (P = 0.0004). None of the other independent variables were included in these models. If the assumption that PFI is a measure of the effectiveness of hormonal therapy is true, these results suggest that quantitative ER and PgR levels and age supersede other traditional predictor variables in predicting the hormonal responsiveness of individual breast carcinoma.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1987

New benzoic acid derivatives with retinoid activity: lack of direct correlation between biological activity and binding to cellular retinoic acid binding protein.

In this paper the biological activity of several newly synthesized benzoic acid derivatives of the Am- and Ch- series, which are structurally different from retinoic acid and arotinoids, was examined. These compounds inhibit squamous cell differentiation of rabbit tracheal epithelial cells in vitro as indicated by the inhibition of transglutaminase Type I and cholesterol 3-sulfate levels. In contrast to the inhibition of differentiation in rabbit tracheal cells, these compounds induce differentiation of mouse embryonal carcinoma F9 and human promyelocytic leukemia HL60 cells. The Am- and Ch- series of compounds also affect several parameters of cell proliferation. These agents are very potent inhibitors of growth of melanoma S91 cells and inhibit the induction of ornithine decarboxylase activity by phorbol 12-myristate 13-acetate in 3T6 fibroblasts. These results show that the Am- and Ch- derivatives elicit in several cell systems the same cellular responses as retinoic acid. We propose, therefore, that they exhibit mechanism(s) of action similar to those of retinoids. Comparison of the biological response with the binding capacity to the cellular retinoic acid-binding protein shows a lack of a direct correlation.

Animals↗
PubMed1987

Transfusion-acquired HIV infection among immunocompromised hosts.

This survey suggests that HIV infection in immunocompromised hosts is characterized by a high attack rate, short incubation time to clinical sequelae, and WB and RIP seropositivity which may precede evidence of antibodies by ELISA by weeks or months. The functional properties of patients' serum antibodies, such as neutralizing activity against HIV in vitro, may correlate with clinical course.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Structural and physiological properties of mengovirus: avirulent, hemagglutination-defective mutants express altered alpha (1 D) proteins and are adsorption-defective.

Structural and physiological properties of two mutants of mengovirus, 205 and 280, were compared to those of wild-type virus to understand the molecular basis of changes exhibited in their biological function. Two dimensional gel electrophoresis of wild-type and mutant structural proteins revealed alterations in the isoelectric character of the alpha (1 D) protein of both mutant 205 and 280. These data suggest that alterations in the alpha (1 D) protein may be responsible for the phenotypic changes by the mutants. A delay in detectable virus-specified protein synthesis was exhibited in mutant-infected cells in comparison to wild-type. The amount of RNA synthesized in mutant- and revertant-infected cells was less than that synthesized in wild-type infected cells. Changes in virus-specified macromolecular synthesis in mutant and revertant-infected cells reflected a decrease in the ability of the viruses to attach to cells.

Animals↗
PubMed1987

Biological properties of mengovirus: characterization of avirulent, hemagglutination-defective mutants.

Biological properties of two mengovirus mutants, 205 and 280, were compared to those of wild-type virus. The mutants exhibited alterations in plaque morphology, hemagglutination, and virulence in mice, but were not temperature-sensitive. Agglutination of human erythrocytes by mengovirus was dependent on the presence of sialic acid on the erythrocyte surface; however, free sialic acid failed to inhibit hemagglutination. Glycophorin, the major sialoglycoprotein of human erythrocyte membranes, exhibited receptor specificity for wild-type virus, but not for mutants 205 or 280. Cross-linking studies indicated that glycophorin exhibited binding specificity for the alpha (1 D) structural protein. The LD50 titers for wild-type mengovirus were 7 and 1500 plaque forming units (PFU) in mice infected intracranially (IC) and intraperitoneally (IP), respectively. However, mice infected IC or IP with 10(6) or 10(7) PFU of mutant 205 or 280 did not exhibit symptoms indicative of virus infection. Revertants were isolated from the brains of mice infected with mutant 205, but not from the brains of mice infected with mutant 280. The biological characterization of the revertants indicated that hemagglutination and virulence may be phenotypically-linked traits.

Animals↗
PubMed1987

Nonspecific electrocardiographic abnormality as a predictor of coronary heart disease: the Framingham Study.

The risk of developing overt coronary heart disease is examined in relation to occurrence of non-specific electrocardiographic S-T and T-wave abnormalities (NSA-ECG) in the Framingham Study. In the course of follow-up, 14% of the 5127 men and women had or developed NSA-ECG without clinically apparent intervening coronary heart disease. During 30 years of surveillance, 760 men and 578 women developed a first overt clinical manifestation of coronary heart disease. NSA-ECG appears to be a hallmark of a compromised coronary circulation which predicted the occurrence of every clinical manifestation of coronary heart disease independently of known risk factors including hypertension, its chief determinant. Coronary morbidity and mortality was increased twofold in each sex. The more common T-wave abnormality alone carried a significant increased risk, although the combination of S-T and T-wave seemed most hazardous. Persons who develop NSA-ECG without other explanation warrant vigorous preventive management against coronary heart disease.

Adult↗
PubMed1987

Inactivation of antiadherence effect of bladder surface glycosaminoglycans as possible mechanism for carcinogenesis.

We have shown that the urinary bladder secretes and binds to its surface a glycosaminoglycan layer whose nonspecific antiadherence effect protects the bladder from infection and perhaps from stone formation. If bladder cancer is caused by agents present in the urine, as is widely believed, this mechanism may also protect against carcinogenesis. We performed the current study to determine whether suspected carcinogens or cocarcinogens in the urine gain access to the transitional cells by impairing or inactivating the surface antiadherence effect. Using an in vivo method to quantitate bacterial adherence to the rabbit bladder, we compared adherence in control and glycosaminoglycan-deficient bladders to adherence in bladders treated with one of several suspected urinary carcinogens. There were statistically significant differences between adherence in control bladders and adherence in bladders treated with the tryptophan metabolites 3-hydroxykynurenine and 3-hydroxyanthranilic acid, sodium cyclamate, and sodium saccharin. These data indicate that perhaps certain suspected urinary bladder carcinogens inactivate the anti-adherence effect of the glycosaminoglycan layer at the bladder surface and thereby penetrate to the transitional cells to exert their tumorigenic effects; or they may serve as cocarcinogens that inactivate the glycosaminoglycan barrier and permit other urinary carcinogens to transform the transitional cells.

3-Hydroxyanthranilic Acid↗