How to handle a bomb threat.
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Disaster Planning↗
Biomedical subjects
D Ferguson
Publications and source records attributed to D Ferguson.
Strain related variations in adenovirally mediated transgene expression from mouse hepatocytes in vivo: comparisons between immunocompetent and immunodeficient inbred strains.
High efficiency gene transfer and gene expression in hepatocytes in vivo can be achieved using recombinant adenoviral vectors. However, the persistence of gene expression in different experimental animal models has been variable. To determine if similar differences could be observed in a single species, persistence of gene expression was studied in inbred strains of mice using a recombinant adenoviral vector that expresses human alpha 1-antitrypsin. Marked variability in the persistence of gene expression ranging from several weeks (C3H/HeJ and Balb/c) to more than 3 months [C57Bl/6, B10.A(2R) and B10.BR] was observed when this vector was transduced in different strains of inbred mice. This variability did not correlate with H-2 type. To evaluate the role of T and B cell immunity in the persistence of gene expression, congenic C3H-scid and Balb/c-scid mice were studied and found to have indefinite gene expression from transduced hepatocytes. These animals unlike their immunocompetent counter-parts were able to undergo secondary transduction of hepatocytes with a different recombinant adenoviral vector. These findings suggest that as yet unidentified genetic loci influence the persistence of adenovirus-mediated hepatic gene expression in vivo, and these effects are mediated at least in part, by the antigen specific immune system.
Adenoviridae↗
Fine specificity of class I MHC recognition in islet allografts.
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Animals↗
A novel nonpeptide HIV-1 protease inhibitor: elucidation of the binding mode and its application in the design of related analogs.
HIV-1 protease has been identified as a significant target enzyme in AIDS research. While numerous peptide-derived inhibitors have been described, the identification of a nonpeptide inhibitor remains an important goal. Using an HIV-1 protease mass screening technique, 4-hydroxy-3-(3-phenoxypropyl)-2H-1-benzopyran-2-one (1) was identified as a nonpeptide competitive inhibitor of the enzyme. Employing a Monte Carlo-based docking procedure, the coumarin was docked in the active site of the enzyme, revealing a binding mode that was later confirmed by the X-ray crystal analysis. Several analogs were prepared to test the binding interactions and improve the overall binding affinity. The most active compound in the study was 4,7-dihydroxy-3-[4-(2-methoxyphenyl)butyl]-2H-1-benzopyran-2-one (31).
4-Hydroxycoumarins↗
Competitive inhibition of HIV-1 protease by warfarin derivatives.
The oral anticoagulant warfarin (4-hydroxy-3-(3-oxo-1-phenylbutyl)- benzopyran-2-one) is a structurally novel low micromolar competitive inhibitor of HIV-1 protease in vitro. It was recently reported that warfarin inhibits HIV-1 infection in U-1 monocytes and viral production in ACH-2 lymphocytes (Bourinbaiar, A.S. et al., (1993) AIDS 7, 129-130). Our results demonstrate that warfarin and a series of structurally related analogs inhibit the viral protease, the most potent analog having an IC50 = 1.9 microM. Kinetic analysis reveals inhibition by warfarin occurs in a competitive manner, with Ki = 3.3 microM. While it is unclear whether the cellular inhibition previously reported is due to inhibition of HIV-1 protease, the warfarin analogs are a novel class of nonpeptide HIV-1 protease inhibitors.
HIV Protease Inhibitors↗
Competitive inhibition of HIV-1 protease by 4-hydroxy-benzopyran-2-ones and by 4-hydroxy-6-phenylpyran-2-ones.
The nonpeptide compounds C1 (4-hydroxy-3-(3-phenoxypropyl)-1-benzopyran-2-one) and P1 (4-hydroxy-6-phenyl-3-(phenylthio)pyran-2-one) are structurally novel low micromolar inhibitors of the protease of human immunodeficiency virus type 1 (HIV-1). Kinetic analysis revealed that both compounds are competitive inhibitors, with Ki values of 1.0 microM (C1) and 1.1 microM (P1), that act in a reversible fast-binding manner. Structural analogs of both compounds indicate that the pyran-2-one group, the 4-hydroxyl group and substitution at the 3 position are all necessary for inhibitory activity. These two pyranones provide excellent initial compounds in the development of therapeutically effective HIV-1 protease inhibitors, since they are small achiral nonpeptide molecules more easily synthesized and with potentially better pharmacological characteristics than peptide inhibitors of the protease.
Amino Acid Sequence↗
Communication skills in veterinary education.
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Communication↗
Clinical experience of the detection of prostate cancer in patients with benign prostate hyperplasia treated with finasteride. The Finasteride Study Group.
The clinical experience relating to the detection of prostate cancer in patients participating in 2 large multicenter clinical trials of finasteride in the treatment of benign prostatic hyperplasia is reviewed. A total of 1,645 patients 40 to 83 years old with benign prostatic hyperplasia was randomized to receive 1 or 5 mg finasteride or placebo once a day for 12 months in a double-blind fashion followed by an open extension study in which all patients were treated with 5 mg finasteride daily. At entry, all patients were to have a maximum urinary flow rate of 15 ml per second or less with a voided volume of 150 ml or more, an enlarged prostate and symptoms of urinary obstruction. Patients with a prostate specific antigen level of 40 ng/ml or more, or any finding suggestive of prostate cancer were excluded. During the study period 32 cases of prostate cancer were diagnosed: 12 were detected during the 12 months of the controlled study and were evenly distributed among the treatment groups (4 on placebo, and 3 on 1 mg and 5 on 5 mg finasteride) and 20 cases were detected in the extension study. From these results we conclude that finasteride-treated patients should be evaluated periodically by digital rectal examination, careful monitoring of prostate specific antigen levels and appropriate investigation of any suspicious findings.
Aged↗
Microcirculatory failure determines lethal hepatocyte injury in ischemic/reperfused rat livers.
The contribution of microcirculatory failure to ischemia/reperfusion injury in isolated perfused rat livers was investigated using intravital epifluorescence videomicroscopy. The degree of microvascular shut-down during reperfusion was modulated by the reperfusion conditions: flow-controlled (10 ml/min), in which microcirculatory failure is minimized by maintenance of constant flow through the liver, and pressure-controlled, in which microvascular shut-down is allowed to occur. Livers underwent 60 min of ischemia, 90 min of ischemia, or no ischemia (control). Perfused sinusoids and dead hepatocytes were quantified in 10 standardized microscopic fields (9000 microns2) per liver during off-line video playback. With flow-controlled reperfusion, microvascular (sinusoid) shut-down was largely avoided; a maximum of 21% of the sinusoids failed to conduct flow. Pressure-controlled reperfusion, however, resulted in early and severe shut-down. A significant decrease of approximately 20-30% was found after 60 min of ischemia and 30 min of reperfusion, while, after 90-min ischemia and 90-min reperfusion, 90% of the sinusoids failed to conduct flow. The appearance of dead hepatocytes correlated well with the number of perfused sinusoids (r = -0.78 for flow controlled, r = -0.97 for pressure-controlled). Only an occasional dead hepatocyte was observed with control perfusion, while up to 50% stained with propidium iodide following 90-min ischemia and 90-min reperfusion under pressure-controlled conditions. These results indicate that loss of sinusoidal flow can be ameliorated by flow-controlled reperfusion; moreover, hepatocyte necrosis during reperfusion is highly dependent upon the integrity of the microcirculation.
Animals↗
Coordinate pulsatile insulin secretion by chronic intraportally transplanted islets in the isolated perfused rat liver.
In the present studies we sought to address the following questions: do chronically transplanted intrahepatic islets (IHI-Tx) secrete insulin in a coordinate pulsatile manner, and, if so, is reestablishment of this coordinate pulsatility a function of time after transplantation? We studied isolated perfused livers at 10 mM glucose from 27 rats rendered diabetic with streptozotocin and then transplanted with approximately 2 x 10(3) islets, 2 (n = 5), 7 (n = 5), 30 (n = 5), and 200 (n = 12) d after transplantation. 12 out of 12 of the 200-d IHI-Tx secreted insulin in coordinate pulses (frequency 3.9 +/- 0.3 pulses/h, amplitude 15.2 +/- 2.4 nmol/min). In contrast, one out of five 2-d, zero out of five 7-d, and one out of five 30-d IHI-Tx showed pulsatile insulin secretion. Insulin secretion was markedly greater (76 +/- 13 vs 13 +/- 3 nmol/min, P < 0.0001) in the 200-d versus early IHI-Tx. Pentobarbital 25 micrograms/ml had no effect on total (13.9 +/- 3.9 vs 15.9 +/- 3.9 nmol/min), nonpulsatile (12.9 +/- 3.5 vs 14.1 +/- 3.3 nmol/min), or pulsatile (pulse amplitude 17.6 +/- 4.5 vs 20.0 +/- 4.2 nmol/min, pulse frequency 4.1 +/- 0.3 vs 4.0 +/- 0.7 pulses/h) insulin secretion. Using synaptophysin, islet innervation was documented in 12 out of 12 200-d IHI-Tx but in none of the early IHI-Tx. We conclude that established (approximately 200 d) IHI-Tx secrete insulin in a coordinate pulsatile manner and that establishment of coordinate pulsatile insulin secretion by IHI-Tx is accompanied by increased total insulin secretion and is associated with islet reinnervation.
Animals↗
Comparison of quantitative cytomegalovirus antigenemia assay with culture methods and correlation with clinical disease.
Blood samples, obtained predominantly from human immunodeficiency virus-infected patients and solid-organ and bone marrow transplant recipients, were submitted to the clinical laboratory for detection of cytomegalovirus (CMV) and were processed by three methods: conventional culture, centrifugation culture, and CMV antigenemia assay with monoclonal antibodies (Clonab CMV; Biotest Diagnostic Corporation, Denville, N.J.) to CMV antigens. Of 496 blood samples tested, 107 were positive by one or more methods: 56 were positive by conventional culture, 27 were positive by centrifugation culture, and 97 were positive for CMV antigen (Ag) by the antigenemia assay. Forty-seven samples were positive by the CMV antigenemia assay only; in these samples, a mean of 12 Ag-positive cells was detected per 200,000 polymorphonuclear leukocytes examined. In contrast, samples positive by the CMV antigenemia assay and both culture methods had a mean of 193 Ag-positive cells, and samples positive by the CMV antigenemia assay and conventional culture alone had a mean of 157 Ag-positive cells. In the antigenemia assay, paraformaldehyde fixation resulted in superior cell morphology when compared with acetone fixation. Use of immunofluorescence staining reduced sample processing time and the complexity of reagent preparation in comparison with immunoperoxidase staining. Differences in the sensitivities between the immunofluorescence and immunoperoxidase staining techniques for detection of antigenemia were minor, with discrepant samples showing only one or two Ag-positive cells. Clinical disease was generally associated with high-level antigenemia, but exceptions were noted. The CMV antigenemia test is a rapid, quantitative assay that greatly facilitated the rapid diagnosis of CMV infection. However, quantitation of antigenemia is labor-intensive, requires processing of samples soon after collection, and does not always correlate with clinical disease in the individual patient.
Adolescent↗
Comparison of latex agglutination test with enzyme-linked immunosorbent assay for detection of antibody to varicella-zoster virus.
A new latex agglutination (LA) test (VZVscan; Becton Dickinson, Cockeysville, Md.) was compared with an enzyme-linked immunosorbent assay (ELISA) (Varicella STAT; Whittaker Bioproducts, Walkersville, Md.) for detection of varicella-zoster virus (VZV) antibody. Of 165 samples tested, 126 (76%) were positive by LA, 123 (73%) were positive by ELISA, and 35 (21%) were negative by both methods. Six samples (4%) were LA positive and ELISA negative or equivocal; three samples (2%) were ELISA positive and LA negative. However, LA failed to detect seroconversions in four adults with varicella in samples obtained 14 to 17 days after the onset of rash. These same samples had ELISA values in the high-positive range. In addition, the recommended LA screening dilution (1:2) is not supported by published data and should be changed.
Adult↗
Spatial relationship between leukocyte accumulation and microvascular injury during reperfusion following hepatic ischemia.
In order to further elucidate the possible contribution of leukocytes to microvascular injury during reperfusion following total hepatic ischemia, we studied the spatial relationship between areas of white cell accumulation and areas of microvascular damage in the rat liver in vivo. No-flow hepatic ischemia was produced for 90 min in vivo and during the ensuing reperfusion phase (I/R) leukocyte accumulation, absolute number of perfused sinusoids per unit area, and red blood cell velocity were quantitated using in vivo epi-fluorescence video microscopy. The total number of stationary leukocytes in the liver during reperfusion was found to be significantly elevated following ischemia compared to time-matched sham-operated controls. In addition, by 2 hr of reperfusion, approximately 80% of the leukocytes in the I/R group were extravascular compared to only about 50% in the controls. When leukocyte accumulation and microhemodynamics were expressed on the basis of whole liver, the increased accumulation of leukocytes was associated with decreased microvascular perfusion as indicated by decreased number of sinusoids perfused and decreased red blood cell velocity. However, when the data were analyzed on the basis of .05mm2 microscopic fields on the surface of the liver, there was no difference in leukocyte accumulation in areas with sinusoidal blood flow compared to areas that were devoid of perfused sinusoids. Moreover, in a correlation analysis of number of adherent leukocytes/microscopic field vs red blood cell velocity in perfused sinusoids in that field, only a very small negative correlation between leukocytes/field and red blood cell velocity was found (r = -.23, p < .05). These results demonstrate that at the whole organ level leukocyte accumulation appears to correlate well with microvascular damage; however, this increase in whole liver accumulation of leukocytes does not necessarily reflect accumulation at sites of overt microvascular damage. Thus, leukocyte-independent factors are likely to be of considerable quantitative importance in microvascular injury during reperfusion following hepatic ischemia.
Animals↗
Parameters affecting the frequencies of transformation and co-transformation with synthetic oligonucleotides in yeast.
Factors influencing the direct transformation of the yeast Saccharomyces cerevisiae with synthetic oligonucleotides were investigated by selecting for cyc1 transformants that contained at least partially functional iso-1-cytochrome c. Approximately 3 x 10(4) transformants, constituting 0.1% of the cells, were obtained by using 1 mg of oligonucleotide in the reaction mixture. Carrier, such as heterogeneous oligonucleotides, enhanced transformation frequencies. Transformation frequencies were dramatically reduced if the oligonucleotides had a large number of mismatches or had terminally located mismatches. Transformation with oligonucleotides, but not with linearized double-strand plasmid, was efficient in a rad52- strain, suggesting that the pathway for transformation with oligonucleotides is different from that with linearized double-strand plasmid. We describe a procedure of co-transformation with two oligonucleotides, one correcting the cyc1 defect of the target allele in the host strain, and the other producing a desired amino acid alteration elsewhere in the iso-1-cytochrome c molecule; approximately 20% of the transformants obtained by co-transformation contained these desired second alterations.
Amino Acid Sequence↗
Problems in measuring heart rate variability of patients with congestive heart failure.
Heart rate variability (HRV) has become an important noninvasive measure of the integrity of the autonomic nervous system in various disease states. The power spectrum of HRV is a means to separate the instability oscillations of the various feedback mechanisms that contribute to cardiovascular homeostasis. The reliability of HRV data is largely unexplored. The day-to-day correlations in the low and mid-frequency components of HRV spectra average 91%, and that of the high-frequency component averages 81%. The correlations among spectral and nonspectral measures of HRV (SD) for the same data segment average 50-60%, suggesting that they encode similar information. Heart rate variability spectra exhibit diurnal variation consistent with physiologic expectation: respiratory sinus arrhythmia (thought to be mediated by parasympathetic tone) and to a lesser extent, the low-frequency spectral component (thought to be of mixed sympathetic-parasympathetic origin) are higher at night than in the daytime; the mid-frequency component (associated with the baroreflex, which is more excited when the patient is upright) is slightly higher during the daytime. Increased frequency of ectopic beats, such as occurs in congestive heart failure, reduces the reliability of the power spectrum since the number of usable data segments falls off rapidly with even small increases in rate of ectopy, and the variance of the estimate (in the method of averaged periodograms) is inversely proportional to the square root of the number of data segments. Using shorter data segments increases the number of segments available, but reduces resolution. Interpolation over ectopic beats (by either linear or cubic splint interpolation) increases the apparent power in low frequencies.(ABSTRACT TRUNCATED AT 250 WORDS)
Electrocardiography↗
Intestinal villus microcirculatory response to hemorrhage in adult and immature rats.
The response of the villus microcirculation to moderate hemorrhage was compared in adult and immature rats. As an estimate of villus blood flow, flux of red blood cells through the terminal arteriole loop at the villus tip was quantified in vivo using fluorescence epilumination videomicroscopy. Baseline red blood cell flux and mean arterial pressure (MAP) of immature rats (973 cells/s, 84 mm Hg) were significantly less than that of adults (1,435 cells/s, 131 mm Hg). Following hemorrhage of 30% of estimated blood volume, MAP of immature rats was still 24% less than that of adults; however, villus flux was not significantly different (578 cells/s immature, 640 cells/s adult; P = .63). Thus, as indicated by changes in villus flux, immature rats do not appear to be more susceptible to acute intestinal blood flow reduction induced by a single moderate hemorrhage. Immaturity of villus microvascular anatomy and of intestinal vasoregulatory mechanisms may account for the differential response.
Age Factors↗
Multicenter, randomized, double-blind, placebo controlled study to investigate the effect of finasteride (MK-906) on stage D prostate cancer.
A total of 28 untreated patients with asymptomatic, stage D prostate cancer was randomized in a double-blinded fashion to receive finasteride (10 mg. per day), a 5 alpha-reductase inhibitor or placebo. Patients were evaluated at 3-week intervals by rectal examination, and serum prostate specific antigen (PSA) and prostatic acid phosphatase (PAP) levels, and at 6-week intervals by bone scan and transrectal ultrasound determinations of prostatic volume. Patients stopped the medication at week 6 at the discretion of the investigator when PSA levels increased from baseline. After 12 weeks all patients were reevaluated. Of the patients 13 received finasteride and 15 received placebo. The 2 groups did not differ statistically with respect to patient age, initial PSA and PAP level, or the extent of metastases on initial bone scan. A statistically significant decrease in the median percentage change from baseline in PSA at weeks 3 and 6 occurred in the finasteride group compared to the placebo group (-22.9% versus -2.9% and -15.1% versus +11.7%, respectively, p less than 0.05). Finasteride had no effect upon PAP, serum testosterone, prostatic volume or appearance of bone scans. A decrease in serum PSA in the finasteride treatment group suggests that finasteride exerts a minor effect in patients with prostate cancer. This effect does not approach that seen with medical or surgical castration yet because of the potency preserving feature and the lack of toxicity finasteride may warrant further study in the treatment of prostate cancer.
5-alpha Reductase Inhibitors↗
Dietary glucose and fat attenuate effects of adrenalectomy on energy balance in ob/ob mice.
The body energy balance response of ob/ob mice to adrenalectomy is diet dependent. Diets varying in source of carbohydrate (starch, glucose or fructose), fat to starch ratio, or fat to glucose ratio were fed to determine influences on energy balance in female adrenalectomized ob/ob mice. Adrenalectomy lowered food intake in all ob/ob mice to values comparable to those of lean mice independent of diet, but the percentage of dietary energy retained as body energy in adrenalectomized ob/ob mice was lowered to values comparable to those of lean mice only in mice fed starch or fructose, not in mice fed glucose or fat. Consumption of either high glucose or high fat diets blocked about one-half the overall effect of adrenalectomy on energy balance in ob/ob mice. Hyperinsulinemia was associated with the high efficiency of energy retention observed in adrenalectomized ob/ob mice fed glucose, but high efficiency of energy retention occurred in adrenalectomized ob/ob mice fed high fat diets without concomitant hyperinsulinemia. Adrenalectomy-induced changes in brain weight and protein content, body protein content and plasma thyroid hormone concentrations in ob/ob mice were independent of diet consumption. Combined adrenalectomy-ovariectomy diminished, but did not eliminate, the diet-dependent influences on energy balance in ob/ob mice. In conclusion, dietary glucose and dietary fat both attenuate effects of adrenalectomy on energy balance in ob/ob mice by promoting high efficiencies of energy retention.
Administration, Oral↗