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Biomedical subjects

J Diggs

Publications and source records attributed to J Diggs.

12 recordsLinked to original sources
PubMed1991

Thrombomodulin expression by human blood monocytes and by human synovial tissue lining macrophages.

Thrombomodulin is an essential cofactor for the activation of the anticoagulant protein C by thrombin. We have identified the expression of thrombomodulin messenger RNA (mRNA) and protein in peripheral blood monocytes. While untreated monocytes expressed thrombomodulin mRNA by Northern blot analysis, lipopolysaccharide-treated cells had decreased mRNA expression. Thrombomodulin antigen was shown in the cytoplasm and on the surface of monocytes by immunohistochemical staining, and thrombomodulin activity was shown on the surface of intact monocytes. One population of synovial lining cells that normally expressed mononuclear phagocyte antigens also expressed thrombomodulin in both noninflamed osteoarthritic synovium and in inflamed rheumatoid arthritis synovium. However, these cells did not express another endothelial protein, von Willebrand factor. We conclude that both circulating and tissue mononuclear phagocytes are capable of expressing thrombomodulin.

Arthritis, Rheumatoid↗
PubMed1986

Early changes in experimental hydrocephalus.

In acute obstruction of the cerebral spinal fluid (CSF) absorption pathways, fluid is produced more rapidly than it is absorbed, and the ventricles enlarge proximal to the obstructions. Communicating hydrocephalus results from a difference between the rates of production and absorption of cerebrospinal fluid. In animals with chronic communicating hydrocephalus, the initial pathologic changes appear to involve the periventricular tissue near the angles of the lateral ventricles. The present investigation was designed to identify the various changes associated with the production of communicating hydrocephalus in acutely hydrocephalic preparations and to relate these findings to those found in experimental animals with chronic communicating hydrocephalus. The results of this study seem to confirm that the changes noted in the chronically hydrocephalic animals occur as early as 12 hours after the restriction of the normal flow of CSF.

Animals↗
PubMed1986

Influence of NMR measuring sequences and gradient variation on signals from flowing systems. Magnetic resonance tomography on experimental models.

The influence of flow on MR tomography images and signal intensities has been studied using experimental model tubes and an aqueous NiCl2 solution having the same relaxation time as human blood. We applied the inversion recovery (IR) and the spin-echo (SE) sequence on a .15T MR tomography system. The influence of RF pulse distance (tau) in the IR and SE experiment as well as the influence of magnetic z-gradient strength on the flow images has been investigated. IR images revealed that signals from flowing systems recover more rapidly due to influx of non-inverted longitudinal magnetization into the scan slice. SE images in presence of flow are characterized by signal intensity loss with increasing time caused by the outflow and dephasing of transverse magnetization. With increasing strength of the z-gradient, the MR signals of flowing fluids decrease drastically. Thus for detection of flow, all the above mentioned parameters are of importance.

Blood↗
PubMed1985

Enzyme immunoassay versus plaque neutralization and other methods for determination of immune status to measles and varicella-zoster viruses and versus complement fixation for serodiagnosis of infections with those viruses.

Results by an enzyme immunoassay method (EIA) performed at one serum dilution and results by indirect immunofluorescence (IFA) and hemagglutination inhibition (HI) tests performed at step dilutions were correlated with results by a neutralization test (50% plaque neutralization [PN]) performed at step dilutions on single serum samples for serologic evaluation of immunity status to measles virus. PN results were taken as true indicators of immunity, and the other tests were evaluated on that basis. The predictive value of a positive result being positive also by PN was 95.3% for HI and 93.3% for EIA and IFA. The predictive value of a negative result being negative also by PN was 81.1% for HI, 100% for EIA, and 75.0% for IFA. A similar study on immunity status to varicella-zoster virus by EIA and by an anticomplement immunofluorescence test versus PN showed a 100% predictive value of a positive or negative result by EIA. By the anticomplement immunofluorescence test, the predictive value of a positive result was 97.7%, and that of a negative result was 88.5%. Studies on the comparative ability of EIA versus complement fixation (CF) to detect significant changes in antibody concentration between acute-phase and convalescent-phase serum samples indicative of a current infection were also done. Both tests were satisfactory for the serodiagnosis of measles or varicella-zoster virus infections. However, EIA was preferable to CF because it was less technically difficult, less labor intensive, and could be performed on sera that were anticomplementary in CF reactions.

Antigens, Viral↗
PubMed1984

Hexabrix as a contrast agent for hysterosalpingography.

Hexabrix, a monoacidic dimeric iodinated contrast material, was compared with Renografin 60 (diatrizoate meglumine) for safety, tolerance, and efficacy in hysterosalpingography, in a double blind study of 52 patients. No serious adverse reactions were noted in either group of patients. Discomfort during and after the procedure was not statistically different in the two groups. No difference in radiographic quality was seen. It was concluded that Hexabrix, despite reduced osmolality and increased viscosity, offers no significant benefit over Renografin 60, but it is a safe and acceptable contrast agent for hysterosalpingography.

Contrast Media↗
PubMed1983

Lymphocyte migration in inbred Syrian hamsters with acute measles virus encephalitis.

The migratory pattern of 51Cr-labeled adult lymphocytes, as measured by 51Cr concentration in various tissues, was followed in inbred weanling Syrian hamsters infected intracranially with measles virus. Donor-labeled lymphocytes were inoculated intracardially into infected and control recipients. Increased passage of labeled lymphocytes across the blood-brain barrier was first seen on day 3 post virus inoculation and 1 day prior to development of clinical signs of acute measles encephalitis. 51Cr concentration in the brain increased progressively along with neurologic signs until the death of the hamsters. Aberration of lymphocyte migration peripherally, manifested by reduced presence of labeled cells in lymph nodes and spleen, first occurred 4 days post virus inoculation in those hamsters with clinical signs of disease. By days 5 and 6 post virus inoculation, the concentration of 51Cr in lymph nodes was 30% and 20%, respectively, of that in lymph nodes of control hamsters. Concentration of labeled lymphocytes in lymph nodes and spleen of the occasional virus-inoculated animal that appeared clinically well at time of autopsy was always greater than that in ill hamsters, and was closer to and sometimes equal to the concentration in the corresponding tissues of control hamsters. Thus, increased passage of labeled lymphocytes into the brain and decreased recovery of labeled lymphocytes in lymph nodes and spleen occurred concomitantly with increased neurologic signs of disease. No differences in presence of labeled cells in other tissues tested (liver, lung, thymus and blood) between infected and control hamsters were noted. Labeled lymphocytes from either measles virus or ovalbumin-immunized donors appeared to pass more readily into the brains of ill recipients than labeled lymphocytes from unimmunized donors.

Animals↗
PubMed1983

Digital subtraction angiography: limitations for the detection of pulmonary embolism.

Perfusion lung scanning, magnification pulmonary arteriography, and digital subtraction angiography (DSA) were performed prior to and following Gelfoam embolization of selected pulmonary arteries in eight canines. The sites of embolization were identified in 75% of perfusion lung scans, in 93% of magnification pulmonary arteriograms, in 75% of arterial phase DSA studies, and 100% of parenchymal phase DSA examinations. With technological advances, DSA has the potential to become the examination of choice for the evaluation of patients suspected of having pulmonary emboli.

Angiography↗
PubMed1983

Radiographic techniques to evaluate paintings.

Radiographic techniques may be helpful in evaluation of the condition of paintings for their restoration, preservation, and occasionally to determine their authenticity. On the basis of experience with several of these procedures, the utility of each method is described in reference to specific "diagnoses" regarding paintings. Radiographic techniques have several advantages over other methods; they are nondestructive, they may be used to survey the entire painting, and they are subject to quantitative and serial analysis.

Art↗
PubMed1982

Cell-mediated cytotoxicity toward measles virus-infected target cells in randomly bred Syrian hamsters.

Cell-mediated cytotoxicity (CMC) toward measles virus-infected cells was studied by a (51)Cr release assay with spleen cells from hamsters inoculated with measles virus (strain Lec) or control antigen and with spleen cells from normal hamsters. Spleen cells from measles virus-inoculated hamsters showed greater CMC toward infected than toward noninfected target cells (designated specific CMC). Specific CMC was maximal 7 days after virus inoculation and was declining by 9 to 10 days. Effector cells were present in a nonadherent cell population. Specific CMC was reduced after treatments of effector cells with antithymocyte serum plus complement. The decrease in cytotoxicity was greater toward infected target cells than toward noninfected target cells. Treatment of infected target cells with antimeasles serum did not increase specific CMC by effector cells from the majority of virus-inoculated hamsters. CMC toward infected target cells by normal spleen cells (natural killer cells) or spleen cells from hamsters inoculated with control antigen was approximately the same as, or more often less than, CMC toward noninfected target cells. Natural killer cells were present in a nonadherent cell population. Treatment of natural killer cells with antithymocyte serum plus complement caused a similar decrease in cytotoxicity toward both infected and noninfected target cells. This study demonstrated virus-specific cellular cytotoxicity of effector spleen cells from measles virus-inoculated hamsters. Although the data were compatible with T cells as the source of effector cells in the virus-specific CMC, definitive identification could not be made. Additional membrane markers for better characterization of hamster lymphocyte subpopulations are required.

Animals↗
PubMed1973

Changes in alkaline ribonuclease activity during compensatory renal growth.

Unilateral nephrectomy in rats produces an increase in ribonuclease activity in both nuclear and cytoplasmic fractions of the contralateral kidney. The timing of this increase and the changes in the proportion of free activity to protein-bound activity are different in each fraction. A peak in inhibitor-bound ribonuclease, suggesting a higher amount of inhibitor, was found in the cytoplasmic fraction before the increase in RNA/DNA ratio. Ninety-six hours after the operation, ribonuclease was still significantly increased in both the nuclear and cytoplasmic fractions. The inhibitor-bound activity was increased in proportion to cellular RNA, maintaining a ribonuclease activity per mug of RNA similar to the controls.

Animals↗
PubMedDate not supplied

Relationship of renal hemodynamic and functional changes following intravascular contrast to the renin-angiotensin system and renal prostacyclin in the dog.

Deterioration in renal function has been observed after the use of intravascular contrast media. In an attempt to identify factors responsible for this phenomenon, meglumine iothalamate (Conray 60), in a dosage range of 2.5-3.3 ml/kg, was injected as a bolus into the aorta of dogs. Serial measurements were made of parameters of renal function as well as of changes in aortic and renal venous levels of angiotensin II, renin activity, and 6-keto-PGF1 alpha, the stable metabolite of prostacyclin. The major findings were (1) an initial, brief increase followed by approximately a 20% sustained decrease in renal blood flow and creatinine clearance, (2) no significant changes in angiotensin II and renin levels, and (3) a significant decline in the renal secretory rate of 6-keto-PGF1 alpha. These observations suggest that the suppression of prostacyclin, rather than the activation of the renin-angiotensin system, may contribute to the renal function changes attending the use of intravascular contrast media.

6-Ketoprostaglandin F1 alpha↗