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D J Phillips

Publications and source records attributed to D J Phillips.

At least 19 recordsLinked to original sources
PubMed1995

Hemostatic properties of the SV-40 transfected human microvascular endothelial cell line (HMEC-1). A representative in vitro model for microvascular endothelium.

HMEC-1 is a SV-40T transfected human microvascular endothelial cell line that constitutively expresses RNA transcripts for plasminogen activator inhibitor 1 (PAI-1), tissue-type plasminogen activator (t-PA), protein S (PS), von Willebrand factor (vWF), and thrombomodulin. Tissue factor (TF) can be induced in response to stimulation with tumor necrosis factor alpha (TNF-alpha), interleukin-1 alpha (IL-1alpha) and phorbol 12-myristate 13-acetate (PMA). Proteins corresponding to PAI-1, t-PA, protein S and vWF genes were constitutively released in the culture supernatant. This cell line is a model that will be useful to investigate coagulation/fibrinolytic properties of microvascular endothelium.

Basal Metabolism↗
PubMed1995

Effects of ovariectomy and FecBB genotype on the median charge and circulating half-life of pituitary FSH isoforms of ewes.

This study investigated the effects of short-term (20 days) ovariectomy, the effects of FSH assay (radioimmunoassay, receptor assay or in vitro bioassay) and of FecBB genotype on the characteristics of pituitary FSH from Booroola ewes. Pituitary extracts were obtained from ovariectomized homozygous carriers (BB) and non-carriers (++, n = 8 per genotype) and ovary-intact controls (n = 4 per genotype). The extracts (n = 4 per genotype per treatment) were subjected to agarose suspension electrophoresis and the eluates were assayed by the three FSH methods. There were significant effects of ovariectomy (P < 0.01) and assay system (P < 0.05) but not of genotype on the median charge of FSH isoforms. The mean +/- SEM migration rates for FSH in intact and ovariectomized ewes were 0.469 +/- 0.006 and 0.439 +/- 0.006 albumin mobility units, respectively (P < 0.01), indicating a shift to more basic isoforms after short-term ovariectomy. When the pituitary extracts were subjected to anion-exchange HPLC, there was a significant (P < 0.01) shift to more basic isoforms in the ovariectomized ewes as shown using agarose electrophoresis, and no gene effects were noted. When the pituitary extracts (n = 4-8 per group) were injected into mature female mice, there were no significant effects of ovariectomy or genotype on the circulating half-lives of the pituitary FSH isoforms. These results indicate that after short-term ovariectomy, the increase in plasma FSH concentrations is accompanied by a shift in the median charge of pituitary FSH isoforms without any observable change in their metabolic clearance rates.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

IL-6 upregulates protein S expression in the HepG-2 hepatoma cells.

Several pro-inflammatory cytokines have been shown to be important in the modulation of the procoagulant response. However, what role these cytokines may have in the regulation of coagulation inhibitors is poorly understood. While the hepatocyte is a primary site of synthesis for the anticoagulant protein C and S, it is also a major target cell for the proinflammatory cytokine, IL-6. We have found that stimulation of HepG-2 hepatoma cells with IL-6 (5 ng/ ml) significantly increased the production of the anticoagulant cofactor, protein S, in both a time and dose dependent fashion. This increase was seen at both the RNA and protein level. A mouse monoclonal neutralizing antibody to human IL-6 suppressed the IL-6 effect in a concentration dependent fashion. IL-6 also increased the release of the C4b-binding protein but had no effect on protein C production. When combined with either dexamethasone or soluble IL-6 receptor, the IL-6 response was significantly enhanced. Oncostatin M, a functionally related cytokine, had a similar effect while other related cytokines, IL-11 and leukemia inhibitory factor, only had a marginal effect. IL-1, TGF-beta, and TNF-alpha had no significant effect on protein S production. These results indicate that IL-6 may play an important regulatory role in the anti-coagulant pathway.

Animals↗
PubMed1992

Evaluation of monoclonal antibodies having specificity for human IgG subclasses: results of the 2nd IUIS/WHO collaborative study.

Following the 1st IUIS/WHO Collaborative Study of monoclonal anti-IgG subclass antibodies, a panel of WHO Specificity Reference Reagents (SRR) was established [Jefferis, R., et al. (1985) Immunol. Lett., 10, 223]. At the time, the hope was expressed that further reagents particularly for IgG2, and other allotypic specificities would become available which could be applied in a wide range of assay protocols. The 2nd study reports the evaluation of nineteen anti-subclass and seven anti-allotype monoclonal antibodies. The anti-IgG1 antibody HP6187 was equivalent in performance to the SRR. Others, that were not of the mouse IgG1 isotype, may be useful for particular applications. The anti-IgG2 antibody HP6200 could be a valuable addition to the WHO SRR; it is specific for an epitope in the Fab region but does not have the light chain bias of HP6014. Antibodies of putative allotype specificity exhibited the claimed specificity when used within protocols similar to those employed by the originating laboratory. It appears to be inherent in the nature of the epitopes (allotopes) recognized that it will take several years before reagents applicable to a wide range of techniques will become available.

Antibodies, Anti-Idiotypic↗
PubMed1992

Flow separation in the carotid bulb: prognostic significance.

It has been previously shown that boundary layer or flow separation occurring in the carotid bulb and detected by duplex scanning denotes minimal or no carotid atherosclerotic disease as demonstrated by angiography and reliably predicts aetiology other than carotid artery disease in symptomatic patients. To evaluate outcome at long-term follow-up we prospectively studied 94 patients (48 males, 46 females) who demonstrated bilateral flow separation. Mean age was 61.2 years (27 to 86 years). Mean follow-up was 57 months (5 to 113 months). There was one death during follow-up at 69 months. It was stroke related. Using age and sex specific death rates for the general population 14.3 deaths would be expected for the same average period. By life table analysis, survival was 98.7% at five years compared to a general population expected 5 year survival of 85.9%. There were no strokes at 5 years of follow-up. (Age and sex specific stroke-free survival for Rochester, MN 1970-1974 is 98% at 5 years). TIA-free survival was 99% at one year (n = 87) and 96% at five years (n = 46). It is concluded that the presence of boundary layer separation in the carotid bulb not only indicates absent or minimal atherosclerotic disease, but is predictive of a favourable long-term outcome with respect to mortality and neurological events.

Age Factors↗
PubMed1992

PCR regimen for enhanced specificity and yield of targeted genomic DNA sequences: ras and p53.

By weighting the PCR reaction in favor of specificity for the target sequence in the beginning cycles and for continued efficient amplification of the sequence into later cycles, we were able to show an improvement in the specificity and quantity of amplified ras and p53 sequences. Increased purity and yield of specific products favorably enhanced post-PCR evaluation and interpretation of results using direct sequencing and single-stranded conformation polymorphism (SSCP) analysis when point mutations were present in DNA from tumor cell lines and tissues.

Base Sequence↗
PubMed1992

Bioactive and immunoreactive FSH and immunoreactive inhibin concentrations in the ovine fetus.

The bioactive (B) and immunoreactive (I) pituitary contents/concentrations of FSH, together with the plasma concentrations of B-FSH, I-FSH and I-inhibin were determined in ovine fetuses at days 55, 75, 90 and 135 of gestation (day 145 = term). The pituitary contents and concentrations of B-FSH and I-FSH increased in both sexes with gestational age. The female fetuses had significantly (P < 0.01) higher pituitary contents/concentrations of B-FSH and I-FSH than the male fetuses at days 75 and 135. The pituitary B/I ratios of FSH were not significantly different with age or sex. The plasma concentrations of B-FSH remained relatively constant from days 75 to 135, with no significant differences between sexes or with age. In contrast, the plasma concentrations of I-FSH reached a peak at day 90 and then declined towards term in both sexes. At all gestational ages except day 55, the female fetuses had significantly (P < 0.05) higher plasma concentrations of I-FSH than the males. In both sexes, the plasma B/I ratios of FSH were lowest at day 90 and had increased again by day 135, with the male fetuses having significantly (P < 0.05) higher B/I ratios compared with the female group at days 75 and 135 but not at day 90. At all gestational ages, the plasma concentrations of I-inhibin declined throughout gestation in the female fetuses, whereas in the males they reached a nadir at day 75 and then increased towards term. The concentrations of I-inhibin were significantly (P < 0.01) higher in the male fetuses compared with the females.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

A triangulation method for the quantitative measurement of arterial blood velocity magnitude and direction in humans.

A triangulation method has been applied to a duplex ultrasound scanner to quantify blood flow velocities in two dimensions. A position locating system (PLS) connected to the scanhead locates the sample volume (SV) in 3-D space to a precision of 1 mm. The PLS is used to obtain flow velocity data from two independent lines of sight in the human femoral artery. Data are gathered from anatomic sites of interest along one line of sight. Later the computer directs the SV to interrogate the same points in space from a second line of sight. Water tank studies using both constant velocity and pulsatile string targets were used to validate the method. Velocity magnitudes could be calculated to within 5% error for Doppler angles below 75 degrees for various string depths and speeds; the error in Doppler angle calculation was usually less than 3 degrees. Results from the superficial femoral artery show flow velocity vectors are nearly parallel to the vessel walls. Peak systolic velocity magnitudes range from 63-66 cm/s in three presumed normal individuals. Following the validation studies addressed in this paper, this triangulation approach is intended in future work to document the complex nonaxial character of blood flow that occurs normally at branch points and in regions of intraluminal disease.

Blood Flow Velocity↗
PubMed1990

Effects of the synthetic glucocorticoid dexamethasone on reproductive function in the ewe.

Glucocorticoids have been found to inhibit reproductive function in most domestic species studied but, in the ewe, preliminary reports suggest that glucocorticoids may have little or no effect. This study investigated the effects of the synthetic glucocorticoid dexamethasone on oestrus and ovulation rate in ewes during the breeding season and gonadotrophin secretion in the breeding and non-breeding seasons. In cyclic ewes, dexamethasone treatment at rates of up to 2 mg/day did not affect the natural or pregnant mare serum gonadotrophin-stimulated ovulation rate, or the timing and incidence of behavioural oestrus (P greater than 0.05). Dexamethasone administration (2 mg/day) had no effect on LH secretion or the plasma LH response to a 1 micrograms injection of gonadotrophin-releasing hormone (GnRH) in ovariectomized ewes in the breeding and non-breeding seasons, and did not compromise the inhibition of plasma LH levels during chronic treatment with oestrogen. Similarly, dexamethasone had no effect on plasma FSH concentrations, but significantly (P less than 0.05) reduced the plasma FSH response to a 1 micrograms GnRH injection during chronic negative treatment with oestrogen in ovariectomized ewes. Collectively, these data show that in these experiments dexamethasone did not significantly modify reproductive function in the ewe, a finding that is in contrast to that found in other domestic species.

Animals↗
PubMed1990

Effects of modifying gonadotrophin-releasing hormone input before and after the oestrogen-induced LH surge in ovariectomized ewes with hypothalamo-pituitary disconnection.

The patterns of gonadotrophin-releasing hormone (GnRH) input to the pituitary gland that affect the expression of a positive-feedback event by oestrogen on LH secretion were investigated in ovariectomized ewes with hypothalamo-pituitary disconnection (HPD). In experiment 1, ovariectomized HPD ewes were given hourly i.v. pulses of 250 ng GnRH and an i.m. injection of 50 micrograms oestradiol benzoate (OB). The ewes were given a bolus pulse of 2.25 micrograms GnRH 16 h after injection of OB, followed by half-hourly pulses of 250 ng GnRH for 14 h (treatment A). The LH surge response was significantly (P less than 0.05) greater in these ewes compared with that in ewes given a continuous infusion of GnRH (250 ng/h) after the OB injection, followed by a continuous infusion of 500 ng GnRH/h after the bolus pulse of GnRH (treatment B). When no GnRH was administered after the OB injection, except for the bolus pulse of GnRH (treatment C), the surge response was significantly (P less than 0.05) reduced compared with that in treatment A, and was reduced compared with treatment B. These data suggest that GnRH pulses are important in the generation of the OB-induced LH surge, but that a baseline secretory component can prime the pituitary to some extent. In experiment 2, a doubling of the continuous infusion dose of GnRH used in treatment B to 500 ng/h before the bolus pulse of GnRH and to 1 micrograms/h afterwards (treatment D) gave a similar response compared with treatment A, suggesting that if the baseline input of GnRH is of sufficient magnitude, it can overcome the lack of pulsatile input. In experiment 3, halving the GnRH pulse amplitude used in treatment A from 250 to 125 ng (treatment E) did not reduce the LH surge response, implying that when the GnRH input is in a pulsatile mode, the amplitude of GnRH pulses is less important than the pulsatile nature per se. In experiment 4, removal of GnRH input after the bolus pulse of GnRH (treatment F) significantly (P less than 0.05) reduced the surge response compared with when pulses were maintained (treatment A), indicating that GnRH input is still required once the LH surge has been initiated. Collectively, these experiments show that several forms of GnRH delivery, both pulsatile and baseline, can result in the full expression of a positive-feedback response in ovariectomized ewes treated with oestrogen.

Animals↗
PubMed1990

Testing ultrasonic pulsed Doppler instruments with a physiologic string phantom.

The spatial, temporal, and frequency resolution of conventional ultrasonic Doppler instruments and the time/space distortions in two-dimensional color Doppler imaging systems can be measured using a pulsatile moving string target. The diameter of the string is small compared with the Doppler sample volume, the velocity (speed and direction), acceleration and timing of the string motions are precisely known with reference to the R wave timing mark, and the spatial location of the string is known. A loop of surgical thread or monofilament fishline running between pulleys is driven by a motor that provides constant string speeds from 0.05 to 150 cm/s and variable string speeds programmed to mimic arterial velocity waveforms from the carotid, aortic, and femoral arteries. Constant string speeds are used to evaluate the Doppler sensitivity, frequency processing, and sample volume size; pulsatile movement of the string provides a physiologic model to evaluate the temporal performance of conventional Doppler systems and the temporal and spatial performance of two-dimensional color Doppler imaging scanners.

Blood Flow Velocity↗
PubMed1990

Recent advances in carotid artery evaluation.

This chapter was intended to provide an overview of ultrasound duplex scanning at the human carotid bifurcation. Although results of clinical studies are useful in patient management, much remains to be learned in the area of understanding the disease process and determining what features, obtainable by ultrasound, will predict clinical outcome. Listed below are the important points covered by this chapter. 1. Ultrasound duplex scanning can detect and quantify carotid artery disease with respect to the gold standard of contrast arteriography. 2. Contrast arteriography is not the ideal gold standard for assessment of cartotid artery disease. A new standard incorporating attributes of not only anatomy but also physiology is needed. 3. Using currently available ultrasound systems it is not possible to obtain the Doppler angle (i.e., the angle formed by the transducer axis and the blood flow-velocity vector). This angle is often estimated by the angle formed by the transducer axis and the axis of the blood vessel. This assumes that the flow-velocity vectors are axial, which turns out to be a poor assumption at bifurcations, curves, and sites of intraluminal disease. Specifying the Doppler angle involves assumptions that should always be kept in mind. 4. All Doppler data should be collected at the same angle formed by the sound beam relative to the vessel axis. Whereas results of Doppler studies can be reported in units of either frequency or velocity, assumptions made about the Doppler angle and acquiring data at arbitrary angles can produce large errors when quantifying flow velocities. 5. Blood flow disturbances cannot automatically be equated with the presence of disease. Some disturbances are localized secondary blood flow patterns produced by changes in vascular geometry coupled with pulsatile flow. 6. The lack of blood flow disturbances cannot automatically be equated with a normal or disease-free artery. Accumulation of plaque within the sinus region at the minimal and moderate disease stages appears to eliminate or attenuate local flow disturbances characteristic of a normal bifurcation. 7. An understanding of the blood flow patterns at clinical sites of interest is important to the correct interpretation of data. Both the imaging and pulsed Doppler modalities are essential to this understanding: the imaging capability to place the pulsed Doppler sample volume and appreciate changes in vascular anatomy, and the pulsed Doppler to obtain the character of blood flow at specific sites within the blood vessels.

Carotid Arteries↗
PubMed1989

Specificity and association constants of 33 monoclonal antibodies to human IgA epitopes.

We used an immunofluorescent sequential-saturation-of-antibody assay and an interactive computer program for Scatchard analysis to determine association constants (Ka) of 33 murine monoclonal antibodies (Mabs) specific for human IgA epitopes. Ka ranged from 0.37 to 690 x 10(7) liters per mole (an approximate 1900-fold difference). Specificity was validated with a panel of 18 highly purified IgA1 and IgA2 myeloma proteins and secretory IgA using an immunofluorometric assay. Western blots of bacterial IgA protease digests were used to locate the epitopes of IgA specific Mabs in either the Fab, Fc, or hinge region. Mabs specific for unique epitopes on secretory IgA or free secretory component (FSC) were produced and evaluated.

Animals↗
PubMed1989

Should results of ultrasound Doppler studies be reported in units of frequency or velocity?

There is a current tendency to report the results of ultrasound Doppler studies in units of velocity instead of Doppler frequency. This is probably motivated by the intuitive feeling that blood flow studies should naturally be reported in cm/s and the notion that "velocity" is a normalizing factor for Doppler ultrasound studies. In order to determine velocity, the Doppler angle theta or angle formed by the ultrasound beam and flow velocity vector, must be known. It is not possible, using currently available systems, to obtain an accurate estimate of this angle. The physics related to the Doppler equation are reviewed in this paper along with examples to illustrate the origin and magnitude of errors that could arise when reporting in units of velocity. Guidelines are provided for thinking about and reporting results of Doppler studies in units of velocity. An understanding of the Doppler equation and its use in clinical studies are promoted in this paper to enhance the diagnostic usefulness of Doppler ultrasound studies and to reduce serious errors which could lead to faulty information dictating patient management.

Blood Flow Velocity↗
PubMed1989

An ultrasonic measurement of superficial femoral artery wall thickness.

An ultrasonic measurement of the superficial femoral artery wall thickness was performed on 16 volunteers. The measurement included all echogenic tissue between the lumen of the superficial femoral artery and the lumen of the superficial femoral vein. The average arterial wall plus vein wall thickness in volunteers with peripheral arterial disease was 2.13 +/- 0.87 mm, significantly greater than the 1.27 +/- 0.50 mm found in those without detectable peripheral arterial disease.

Aged↗
PubMed1989

Recommended guide to the evaluation of permanent impairment of the temporomandibular joint.

This paper provides a method to evaluate the extent of permanent injury to the temporomandibular joint. The authors, working as the Committee on Permanent Impairment for the American Academy of Head, Facial, Neck Pain and TMJ Orthopedics, have used the same values as the American Medical Association has used in their Guides to the Evaluation of Permanent Impairment for other disk-protected and functional joints. These Guides may then serve as a tool to help physicians and dentists who treat temporomandibular joint injuries to rate the degree of permanent injury. These Guides may be combined with other areas of impairment that are already described and valued in the Guides to the Evaluation of Permanent Impairment published by the AMA. These Guides provide a range and each injury should be evaluated on an individual basis. We urge you to use these Guides conservatively and in harmony with good clinical judgement.

Disability Evaluation↗