Matrix effects on proficiency testing materials. Impact on accuracy of cholesterol measurement in laboratories in the nation's largest hospital system

The objective of this collaborative study with the Department of Veterans Affairs (VA), College of American Pathologists (CAP), and the Centers for Disease Control and Prevention (CDC) was to quantitate the matrix-induced biases of cholesterol measurements on the CAP Comprehensive Chemistry Surveys materials used in proficiency testing (PT). A total of 174 VA Medical Centers outpatient clinics and clinical laboratories participate in the VA-CDC National Cholesterol Standardization and Certification Program. This study was conducted in 112 VA laboratories that have been standardized for measuring cholesterol accurately (within +/- 3.0% of the CDC reference-method values) using fresh, unfrozen, unadulterated human serum samples. Fresh serum samples and 1990 CAP Surveys materials were sent by overnight mail, and the laboratories were asked to analyze them simultaneously in triplicate in a single analytic batch run. The results showed significant matrix-effect biases with the CAP Surveys materials with six of the eight major peer groups, despite the fact that accuracy of cholesterol measurements was maintained with fresh serum samples. The magnitude and direction (positive or negative) of the matrix-effect biases were instrument, reagent, and method specific using the following peer groups: du Pont Dimension (-8.9%); Beckman CX4, CX5, and CX7 (-5.5%); Kodak Ektachem 400, 500, and 700 (+4.4%); Instrumentation Laboratory Monarch (-3.1%); Baxter Paramax (-2.4%); Technicon SMAC and RA (+1.3%); Hitachi/BMD 704 through 747 (+0.4%); and Abbott Spectrum (-0.3%). The CAP PT materials used currently do not behave in a manner identical to fresh human serum when measuring cholesterol on many, but not all, analytic systems. The observed biases due to "matrix effects" with PT materials will cause incorrect conclusions about the accuracy of many laboratory procedures performed on fresh patient specimens. This matrix-effect phenomenon will severely hamper interlaboratory accuracy transfer, standardization efforts, and monitoring performance of a laboratory's testing accuracy with the use of the current survey materials used in PT programs. Collaborative efforts are needed to (1) improve PT fluids to analytically behave more like fresh, human serum; (2) improve instrument design and reagent formulation; and (3) select methods and methodologic parameters that are more "robust" and less sensitive to the exact character of processed calibrators, quality control, and PT materials.

Intraaortic balloon pump management of refractory congestive heart failure in children

From December 1975 to September 1989, nine children, ages 0.6-15.8 years (mean = 8.1 years) and weighing 5-44 kg (mean = 24 kg), were identified as requiring intraaortic balloon pump support. Indications included ventricular failure refractory to maximal conventional therapy, inability to wean from cardiopulmonary bypass, and myocardial ischemia. Prior to insertion of the balloon catheter, mean systolic blood pressure was 64 mmHg, one to four cardiotonic medications were being administered, mechanical ventilation was being performed in eight patients, and mean urine output was 0.4 ml/kg/min in eight. Following balloon catheter insertion, mean urine output increased to 0.9 ml/kg/min. Four patients survived following discontinuation of the balloon catheter 12-96 h (mean = 59 h) after initiation. Though complications such as loss of distal lower extremity pulses, sepsis, thrombocytopenia, and abdominal distention were observed, most could be attributed to other causes. Thus, the intraaortic balloon pump is a valuable addition to conventional medical therapy in the treatment of refractory cardiogenic shock in children.

Fluid flow during percutaneous drainage procedures: an in vitro study of the effects of fluid viscosity, catheter size, and adjunctive urokinase

OBJECTIVE

An in vitro study was performed to determine the range of flow times of different bodily fluids through catheters of different diameters and to test the hypothesis that urokinase might decrease the viscosity of purulent material.

MATERIALS AND METHODS

A standard viscometer was used to measure the viscosities of water, blood, pseudocyst fluid, purulent material, and purulent material with admixed urokinase. For each fluid, Poiseuille's law was used to calculate the kinematic viscosity, from which theoretical drainage times through seven different sizes of catheters were calculated. These theoretical times were compared with the actual measured values to verify that flow was according to Poiseuille's law.

RESULTS

The calculated kinematic viscosities (in 10(-6) stokes) were as follows: water, 0.695 +/- 0.006; pseudocyst fluid, 2.185 +/- 0.008; blood, 3.001 +/- 0.049; abscess fluid without urokinase, 5.729 +/- 0.064; and abscess fluid with urokinase, 4.416 +/- 0.070. The viscosity of abscess fluid decreased by 23% with the addition of urokinase. Drainage time was considerably shorter with larger catheters.

CONCLUSION

Flow of various bodily fluids, including pus, is according to Poiseuille's law, confirming that for more viscous fluid, larger catheters provide more rapid drainage. Urokinase decreases viscosity of purulent material and increases flow for all sizes of catheters.

Isolation and characterization of a lower molecular weight protein doublet of horny cell outer leaflet: a possible novel epidermal differentiation marker

The water-soluble fraction of stratum corneum contains numerous unidentifiable proteins and polypeptides when examined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Intensely stained polypeptide bands of low molecular weights (LMW) [8 and 10 kDa] are also present, and the abundance and invariable presence of this LMW protein doublet in the soluble proteins of stratum corneum prompted us to isolate and characterize them. Extracts of stratum corneum, using 8 M urea, 0.05 M Tris, pH 9.0, 0.025 M 2-mercaptoethanol, were dialysed against water. Water-insoluble proteins were removed by repeated dialysis and centrifugation. From the remaining soluble proteins, a LMW protein doublet was isolated by Sephadex G50 column chromatography and reversed-phase high-performance liquid chromatography (HPLC). The amino acid compositions of the 8 and 10 kDa proteins were similar to, but different from, those of known structural proteins in the stratum corneum. Rabbit antibody was raised against the 10-kDa protein band and cross-reacted with the 8-kDa protein band by Western immunoblot technique. The antibody recognized only this protein doublet amongst the proteins extracted from cultured keratinocytes. The 8- and 10-kDa proteins therefore appear to be closely related to, but different from, known structural proteins or degradation products. Immunofluorescence and immunoelectron microscopy demonstrated that this protein doublet was located in the cytoplasm of the cells of the malpighian layer, and in the outer layer of the marginal band of the horny layer. Its distribution was shown to be limited to stratified squamous epithelia by organ specificity studies. These results suggest that this protein doublet appears to be a novel soluble protein and a new epidermal differentiation marker of stratified epithelium.

Surgical management of the infant with coarctation of the aorta and ventricular septal defect

Clinical and cardiac catheterization data were collected from 39 infants with coarctation of the aorta and ventricular septal defect, 31 of whom were initially managed only by surgical repair of coarctation. Data were analyzed to determine mortality, morbidity, outcome and factors that might predict survival or the need for septal defect closure. Of the eight patients who did not require surgical treatment before 3 months of age, seven underwent coarctation repair alone at a mean age of 2.3 years. Of the 23 infants managed with coarctation repair alone, before age 3 months, 9 needed no additional surgical treatment and 6 required early and 8 required late repair of the ventricular septal defect. Seven infants underwent coarctation repair and simultaneous pulmonary artery banding and one eventually required debanding after spontaneous closure of the septal defect. The overall mortality rate in this series was 10.3% (mean follow-up time 5.7 years). Of 39 infants, 16 (41%) never required a second operation for ventricular septal defect closure. For patients who had only coarctation or coarctation repair with pulmonary artery banding at less than 3 months of age, ventricular septal defect size was categorized as small (less than 0.5 cm/m2), moderate (less than 1 cm/m2) or large (greater than 1 cm/m2) on the basis of defect size at operative repair or echocardiographic or angiographic assessment. Defect size did not necessarily correlate with the need for operative repair.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinicopathologic correlation and pathogenesis of ocular and central nervous system manifestations in Hallervorden-Spatz syndrome

We have correlated the clinical and histopathologic features of the eyes and central nervous system in a patient with Hallervorden-Spatz syndrome who died at age 11 years. The main ocular findings included degeneration of photoreceptors, marked thinning of the outer nuclear and outer plexiform layers, retinal gliosis, narrowing and obliteration of blood vessels with a perivascular cuffing of pigment cells, and degenerative changes in the retinal pigment epithelial cells with accumulation of melanolipofuscin. The positive findings in the brain included a symmetrical, partially destructive lesion of the globus pallidus, especially in its internal fibers and neurons; in addition, we noted gliosis, widely disseminated axonal spheroidal bodies, which were most numerous in the globus pallidus and pars reticulata, as well as deposits of iron. Our histopathologic findings implicate three possible mechanisms, namely, lipid peroxidation, a deficiency of fatty acid membrane components, and increased cGMP which, either singly or in combination, are responsible for a pathogenesis that is common to the eye and brain in Hallervorden-Spatz syndrome.

A 15-bp deletion in exon 5 of the ornithine aminotransferase (OAT) locus associated with gyrate atrophy

Gyrate atrophy of the choroid and retina (GA) is an autosomal recessive disorder in which a deficiency of the mitochondrial matrix enzyme ornithine aminotransferase (OAT) leads to progressive blindness. Previously, we and others have reported a number of missense mutations and splice defects in the OAT gene associated with GA. In the present case, through sequencing of the PCR amplified cDNA products, we have detected a novel 15-bp deletion within exon 5 of the OAT gene which retains the original reading frame. The deleted PCR product is the only one produced from the patient's mRNA, while mRNA from the patient's mother yields both deleted and normal length PCR products. The alternate, apparently nonexpressing OAT allele in this patient was inherited from the father, who displays only the normal length PCR product. The codon at the deletion joint remains unaltered, predicting the loss of the pentapeptide Tyr-Thr-Val-Lys-Gly without any other amino acid change. The breakpoints are adjacent to or within two copies of a 4-bp direct repeat, which may have implications for the mechanism of deletion.

A complex genetic rearrangement in a t(10;14)(q24;q11) associated with T-cell acute lymphoblastic leukemia

The t(10;14)(q24;q11) is observed in the leukemia cells of 5-10% of cases of T-cell acute lymphoblastic leukemia (T-ALL). Recently, molecular analyses of a number of these translocations revealed simple reciprocal translocations between the T-cell receptor delta chain gene (TCRD) and a region of 10q24. We have characterized, at the molecular level, a t(10;14)(q24;q11) in a patient with T-ALL. The translocation in this case, in contrast to the previous cases, is part of a complex genetic rearrangement. In addition to a reciprocal translocation between the D delta 3 gene segment of TCRD and a region of 10q24, a local inversion occurred within TCRD, involving the D delta 2 and V delta 2 gene segments. As a consequence, the entire joining and constant regions and most of the diversity regions of TCRD are located on the derivative 14 chromosome, whereas the joining and constant regions of TCRA are positioned on the derivative 10 chromosome. The chromosome 10 breakpoint in our patient, as in other t(10;14), clusters within a 9 kb breakpoint region. The occurrence of seven breakpoints within a localized region of chromosome 10 implies the existence of a nearby gene whose activation may have conferred a selective advantage on the leukemia cells. Moreover, as in the previous cases, the translocation in the present study exhibits recombination signal sequences or signal-like sequences adjacent to the breakpoint junction. The presence of such motifs suggests the involvement of the recombinase enzyme system in the generation of this genetic alteration.

CD43, a molecule defective in Wiskott-Aldrich syndrome, binds ICAM-1

THE protein CD43 (also known as sialophorin, leukosialin, large sialoglycoprotein or gp115) is expressed on the surface of T lymphocytes, monocytes, neutrophils, platelets and some B lymphocytes. Expression of CD43 is deficient and/or defective in the X-chromosome-linked immunodeficiency disorder Wiscott-Aldrich syndrome, suggesting that CD43 might have a role in T-cell activation. We have shown that expression of human CD43 in an HLA-DR-specific murine T-cell hybridoma enhances the antigen-specific response to stimulation by the human lymphoblastoid cell line Daudi, and that Daudi cells bind specifically to purified immobilized CD43. These data indicate that the specific interaction of CD43 with a ligand on the surface of Daudi cells might contribute to T-cell activation. Here we report evidence that intercellular adhesion molecule-1 (ICAM-1, or CD54), is a ligand for CD43.

Enhancement of T-cell activation by the CD43 molecule whose expression is defective in Wiskott-Aldrich syndrome

CD43 (sialophorin, leukosialin, leukocyte large sialoglycoprotein), a heavily sialylated molecule found on most leukocytes and platelets, was initially identified as a major glycoprotein of mouse, rat and human T cells. CD43 expression is defective on the T cells of males with the Wiskott-Aldrich syndrome, an X chromosome-linked recessive immunodeficiency disorder. Affected males are susceptible to opportunistic infections and do not respond to polysaccharide antigens, reflecting defects in cytotoxic and helper T-cell functions. Anti-CD43 monoclonal antibodies have a modest costimulatory effect on T cells, natural killer cells, B cells and monocytes, and one such antibody has been shown to activate T cells directly. To investigate a possible physiological role for CD43, a complementary DNA encoding the human protein was introduced into an antigen-responsive murine T-cell hybridoma. We observed that CD43 enhances the antigen-specific activation of T cells and that the intracellular domain of CD43, which is hyperphosphorylated during T-cell activation, is required for this function. We also found that antigen-presenting cells can bind specifically to immobilized purified CD43 and that the binding can be inhibited by liposomes containing CD43 as well as by anti-CD43 monoclonal antibodies.

DNA single stranded gaps formed during DNA repair synthesis induced by methyl methanesulfonate are filled by sequential action of aphidicolin- and dideoxythymidine sensitive DNA polymerases in HeLa cells

DNA repair synthesis induced by methyl methanesulfonate in preconditioned HeLa cells in which DNA replicative synthesis had been highly suppressed was inhibited by aphidicolin (an inhibitor of DNA polymerases alpha and delta) and dideoxythymidine (ddThR, an inhibitor of DNA polymerase beta). Incomplete repair patches sensitive to exonuclease III were accumulated in the presence of aphidicolin while not in the presence of ddThR. These patches were comopleted by the combined action of Klenow fragment and T4 DNA ligase, indicating that the single-stranded gaps were formed during the repair synthesis. Moreover, ddThR had little effect on the repair synthesis in the presence of aphidicolin. Thus, the results suggest that the single-stranded gaps may be sealed first by aphidicolin-sensitive polymerase followed by ddThR-sensitive DNA polymerase on the same site of the repair patch.

Accumulation of polycyclic aromatic hydrocarbon-induced single strand breaks is attributed to slower rejoining processes by DNA polymerase inhibitor, cytosine arabinoside in CHO-K1 cells

We demonstrate a successful induction of DNA single strand breaks in CHO-K1 cells by cocultivation with mouse embryonic fibroblasts (MEF) during exposure to benzo(a)pyrene (BP) or 3-methylcholanthrene (MC). When compared to those induced by methyl methanesulfonate (MMS), the DNA single strand breaks induced by BP and MC were markedly accumulated by post-incubation with cytosine arabinoside (araC) and were much more delayed in their rejoining. These results suggest that the active metabolites of BP or MC produced by cocultivation with MEF or microsomal fraction (S-15) result in the formation of large DNA adducts which require an active participation of DNA polymerase alpha(delta) in the polymerization step of excision repair for their removal.

DIFFERENT PATTERNS OF DNA REPLICATION INHIBITION BY BENZO(A)PYRENE AND 3-METHYLCHOLANTHRENE IN MAMMALIAN CELLS IN VITRO

TWO METABOLIC ACTIVATION SYSTEMS, EXEMPLI GRATIA S15 FRACTION AND MOUSE EMBRYONIC FIBROBLAST (MEF) FEEDER LAYER, HAVE BEEN SHOWN TO HAVE EFFECTS ON THE PATTERN CHANGE OF BENZO(A)PYRENE (BP)- AND 3-METHYLCHOLANTHRENE (MC)-INDUCED DNA REPLICATION INHIBITION. THE PRESENT STUDIES WERE PERFORMED IN ORDER TO ELUCIDATE THE MECHANISM OF SUCH EFFECTS IN CHINESE HAMSTER OVARY CELLS (CHO-K1) USING ALKALINE SUCROSE GRADIENT SEDIMENTATION ANALYSIS. WHEN CHO-K1 CELLS WERE TREATED WITH BP IN THE ABSENCE OF METABOLIC ACTIVATION SYSTEM, INHIBITION OF REPLICON INITIATION AND CHAIN ELONGATION WAS OBSERVED AT 12 HR AND AT 24 HR, RESPECTIVELY, REGARDLESS OF THE DOSE, EVEN THOUGH THE LEVEL OF THE OVERALL REPLICATION INHIBITION WAS VERY LOW. HOWEVER, WHEN THESE CELLS WERE TREATED WITH BP OR MC IN THE PRESENCE OF THE S15 FRACTION FOR 1 HR, THE RATE OF DNA SYNTHESIS WAS GREATLY DECREASED. AT LOW DOSES BELOW 10(-6) M WHEREAS THE CHAIN ELONGATION WAS MARKEDLY INTERRUPTED AT 10(-4) M. THESE RESULTS SUGGEST THAT THE PATTERN OF DNA REPLICATION INHIBITION INDUCED BY MC OR BP COULD BE INFLUENCED TO A GREATER DEGREE BY THE CHOICE OF METABOLIC ACTIVATION SYSTEM EMPLOYED THAN BY THE DOSE OR THE DURATION OF EXPOSURE.

POTENTIATION EFFECTS OF 3-AMINOBENZAMIDE ON DIVALENT CATION-DEPENDENT DNA FRAGMENTATION IN MAMMALIAN CELLS EXPOSED TO METHYL METHANESULFONATE

THE PROPERTIES OF METHYL METHANESULFONATE (MMS) DAMAGE-RELATED NUCLEASE ACTIVITY IN CHO AND HELA CELLS WERE STUDIED BY NEUTRAL AND ALKALINE ELUTION TECHNIQUES. THE FRAGMENTATION OF MMS-TREATED DNA WAS DEPENDENT ON THE PRESENCE OF CA++ AND MG++ IONS, AND WAS NOT OBSERVED UPON TREATMENT WITH DIVALENT ION CHELATORS SUCH AS EDTA OR EGTA. THE CA++ AND MG++ -DEPENDENT CONVERSION OF MMS-TREATED SUPERCOILED PLASMID PREVIOUSLY REACTED WITH CHO CELL NUCLEAR EXTRACT TO OPEN CIRCULAR FORM WAS MARKEDLY INCREASED IN A 3-AMINOBENZAMIDE (3-AB) DOSE-DEPENDENT MANNER AS DETERMINED BY AGAROSE GEL ELECTROPHORESIS AND DENSITOMETRIC ANALYSIS. THESE RESULTS SUGGEST THAT THE INHIBITION OF POLY (ADP-RIBOSE) POLYMERASE BY 3-AB RESULTS IN THE ACTIVATION OF THE CA++, MG++ -DEPENDENT ENDONUCLEASE WHICH NONSPECIFICALLY CUTS MMS-TREATED DNA.

Localization of urokinase-type plasminogen activator in human eyes: an immunocytochemical study

We investigated the presence of urokinase-type plasminogen activator (u-PA) in various structures of the human eye by using a biotin-strepavidin complex immunoperoxidase technique with a monoclonal antibody specific for human u-PA. A moderate to intense reaction product was seen in the corneal endothelium, episclera, sclera, iris muscles, lens equator and posterior capsule, peripheral vitreous, epithelium of pars plana, retinal pigment epithelium, axons, uveal fibroblasts, optic nerve fibers, and extraocular muscles. A weak reaction product was seen in the conjunctival and corneal epithelium, the trabecular meshwork, melanocytes and stroma of the iris and choroid, and the posterior layers of the retina. u-PA was not localized in the corneal stroma, conjunctival goblet cells, and certain parts of the lens. Comparison of the present results with those of our previous study (Tripathi, Geanon and Tripathi, 1987, Ophthalmology, 94, 1434-8) on the localization of tissue plasminogen activator (t-PA) in the eye indicate that the distribution of u-PA and t-PA overlaps in many tissues, but differs significantly in others, and that this finding may be related to their complementary and specific roles. As in other body systems, u-PA in ocular tissues is probably involved in processes such as fibrinolysis, wound healing, turnover of intra- and extracellular macromolecules, muscles and neuromuscular regeneration, synapse formation, and maintenance of general neuronal function.

Alteration of human epidermal transglutaminase during its activation

The effects of enhancement of enzymatic activity by heating at 56 degrees C or by limited treatment with dimethylsulfoxide, trypsin and cathepsin D on two forms (Mr = 50 kDa and 72 kDa) of human epidermal transglutaminase were studied by immunoblots using rabbit antihuman epidermal transglutaminase. Both 50 kDa and 72 kDa transglutaminase bands were detected without any alteration in the mobility of the transglutaminase bands during activation induced by heating at 56 degrees C or by pretreatment with dimethylsulfoxide. With a preincubation period longer than 60 min, the trypsin pretreated sample showed progressive disappearance of the 72 kDa transglutaminase band in conjunction with the loss of transglutaminase activity. On the other hand, samples preincubated with cathepsin D showed a complete disappearance of the 50 kDa band after 180 min. These studies suggest the different forms of human epidermal transglutaminase may regulate enzyme activity each other during normal epidermal differentiation.

Extracellular release of tissue plasminogen activator is increased with the phagocytic activity of the retinal pigment epithelium

Primary confluent cultures of retinal pigment epithelium (RPE) cells harvested from porcine eyes were challenged with latex spheres. The extracellular release of tissue plasminogen activator (t-PA) that was associated with phagocytosis of the beads by the RPE was measured by using enzyme-linked immunosorbent and chromogenic substrate assays. In the presence of serum and as compared to the controls, the phagocytosis of latex spheres produced a 5.5-fold increase in the amount of t-PA released into the ambient medium. Cell lysis was not a significant feature in either treated or control groups. Because the RPE in vivo is exposed to serum through the fenestrated choriocapillaris, and because phagocytosis by the RPE outer segments shed by the photoreceptors contributes to the maintenance of the functional integrity of the neural retina, we suggest that the release of t-PA associated with the phagocytic activity of RPE cells is an important physiologic event.

Two different mechanisms are involved for the bleomycin-induced DNA repair synthesis in permeabilized HeLa cells

Bleomycin-induced DNA repair synthesis in the permeabilized HeLa cells was sensitive to aphidicolin, an inhibitor of DNA polymerase alpha and delta, and to dideoxythymidine triphosphate (ddTTP), a specific inhibitor of DNA polymerase beta. Upon combined treatment with these inhibitors, the DNA repair synthesis was inhibited to an even higher degree. This indicated that the aphidicolin- and ddTTP-sensitive DNA repair syntheses may occur by independent mechanisms. The structure of incomplete repair patches being accumulated in the presence of these inhibitors was investigated by digestion of DNA with exonuclease III after incubation with Klenow fragment and T4 DNA ligase. The results have suggested that the patch accumulating in the presence of aphidicolin is a single-stranded gap made by excision enzyme(s), whereas that accumulating in the presence of ddTTP may be generated by strand displacement.

An (8;14)(q24;q11) translocation involving the T-cell receptor alpha-chain gene and the MYC oncogene 3' region in a B-cell lymphoma

We describe a t(8;14)(q24;q11) involving the T-cell receptor alpha-chain gene (TCRA) and the 3' region of the MYC protooncogene in a B-cell lymphoma. The B-cell origin of this tumor was determined by its histological architecture, by immunophenotypic analysis, and by Southern analysis of immunoglobulin gene rearrangements. An identical fragment encompassing the translocation breakpoint junction was detected through Southern analysis using both a TCRAJ and a MYC probe. The other alleles at the TCRAJ and MYC loci were in the germline configuration. Restriction enzyme and nucleotide sequencing analyses revealed that the breakpoint junction on chromosome 8 lies approximately 700 base pairs (bp) downstream of the 3' end of the third MYC exon; on chromosome 14, the break is located 12.6 kilobases (kb) downstream of the 3' end of the C delta fourth exon. A heptamer-like consensus sequence on chromosome 14 adjacent to the translocation breakpoint implies the involvement of recombinase activity. However, no consensus sequences were found on chromosome 8 within 140 bp in either direction from the breakpoint. It is possible that this translocation involving MYC occurred during an attempt at an inappropriate rearrangement of the TCRA locus in a cell of B-cell lineage.

Velocity field of pulsatile flow in a porous tube

This paper describes velocity fields for fully developed periodic laminar flow in a rigid tube with a porous wall. We obtained an analytical solution of the flow by the linear approximation of the Navier-Stokes equation. Unlike the previous works with a constant seepage rate along the axis, we used a wall velocity which contained hydraulic permeation constant Lp. The axial velocity profile shows a local maximum velocity near the wall at a large Womersley number alpha. This suggests that concentration polarization in porous tubular membrane may be reduced at high frequencies if a membrane device is operated under pulsatile flow conditions. The magnitude of wall permeation velocity decreases linearly along the tube axis because the damping of the pressure difference between the inside and the outside of the tube is very small.

Tissue plasminogen activator in human aqueous humor and its possible therapeutic significance

By using an enzyme-linked immunosorbent assay, we detected a significant amount of tissue plasminogen activator (0.8 +/- 0.17 ng/ml) in the aqueous humor of ten normal human eyes. It was also identified on Western blot analysis. The ratio of tissue plasminogen activator to total protein in aqueous humor was about 30 times greater than the ratio of tissue plasminogen activator to total protein in plasma. There was evidence that at least some of the tissue plasminogen activator in the aqueous humor was synthesized locally by the structures bordering the anterior chamber of the eye. Tissue plasminogen activator may be a useful therapeutic modality in clinical conditions of delayed dissolution of fibrin in the eye.

Prenatal diagnosis of a heterozygote of salt wasting congenital adrenal hyperplasia due to 21-hydroxylase deficiency by genetic linkage analysis

For the purpose of prenatal diagnosis of CAH, genetic linkage analysis by HLA genotyping with lymphocytes and cultured amniotic cells were performed in a family at risk in which two consecutive children had been affected with SW CAH. In addition, the response of serum 17-OHP to intravenous ACTH was determined in obligate carrier parents, and 17-OHP concentration of amniotic fluid was also measured at 16 weeks of gestation. As might be expected, the baseline levels of 17-OHP in obligate parents were significantly higher than that of normal control. Although the post stimulation response of 17-OHP to ACTH in the mother (I-2) was significantly higher than that of normal control, the post stimulation levels of 17-OHP were in normal range in the father (I-1). The 17-OHP level (5.7 ng/ml) in the amniotic fluid showed intermediate value compared to Pang's report (normal less than 30 ng/ml, CAH greater than 12.0 ng/ml) suggesting heterozygote of the fetus. Genetic linkage analysis by HLA genotyping with cultured amniotic cells revealed heterozygote in their fetus (II-3) who has received one chromosome No,6 containing HLA haplotype A24, B40, Cw3 (normal allele for 21-OH) from the father and the other chromosome No,6 containing HLA haplotype A2, Bw62, Cw4 (mutant allele for 21-OH D) from the mother. In conclusion, attempts to detect heterozygote for 21-OH deficiency by ACTH stimulation test were partially successful and prenatal diagnosis of CAH by the hormone studies in ammiotic fluid requires reliable values in normal, heterozygotes and patients group, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Tissue plasminogen activator in the trabecular endothelium

By quantitative analysis of tissue plasminogen activator (TPA) in the trabecular endothelium, corneal endothelium, and iris in the eyes of monkeys and dogs, we found significant levels of TPA activity. In a [125I]fibrin-coated well assay, the levels for the dog and monkey were, respectively: trabecular endothelium, 0.2 and 0.5; corneal endothelium, 0.8 and 0.5 IU per mg protein. The iris tissue showed high TPA activity, but its protein content could not be measured with the techniques employed. Activity in the aqueous humor was not detectable. By the ELISA technique, the values (in ng TPA/mg tissue protein) for the dog and monkey were, respectively: trabecular endothelium, 0.16 and 0.44; corneal endothelium, 0.48 and 0.92. Again, iris tissue showed high TPA activity, whereas the aqueous humor showed low activity (0.86 ng/ml). The data obtained with the two methods showed a reasonable consistency, although a direct comparison was not possible because two separate standards were used. The presence of TPA in the trabecular endothelium, corneal endothelium, and iris may be important in modulating the resistance to aqueous outflow under normal conditions as well as those of hyphema.

Effects of Panax ginseng on blood alcohol clearance in man

1. Fourteen healthy male volunteers were studied to assess the effects of Panax ginseng on blood alcohol clearance, utilizing each subject as his own control. 2. At 40 min after the last drink, the blood alcohol level in the test group receiving ginseng extract (3 g/65 kg body weight) along with alcohol (72 g/65 kg body weight) was about 35% lower than their control values. 3. When the blood alcohol level was compared on individual bases, alcohol concentrations in 10 out of 14 test subjects ranged from 32 to 51% lower than their control values. 4. These results demonstrate that P. ginseng extract enhances blood alcohol clearance in man.

Effects of Panax ginseng extract on the benzo(a)pyrene metabolizing enzyme system

Ethanol extract of Panax ginseng C. A. Meyer, which has been used for centuries as a tonic in Asian countries, exhibited a selective induction of epoxide hydratase and cytosolic glutathione transferase activity without the concurrent induction of aryl hydrocarbon hydroxylase activity. Thus, Panax ginseng appears to have the potential to alter the metabolic patterns of benzo(a)pyrene and its reactive metabolites.

Tyrosine hydroxylase is expressed by neocortical neurons after transplantation

Tyrosine hydroxylase [TyrOHase; L-tyrosine, tetrahydropteridine:oxygen oxidoreductase (3-hydroxylating), EC 1.14.16.2], an essential enzyme in the synthesis of catecholamines, is expressed normally by neurons in the brainstem but not by those in mature neocortex. When embryonic neocortex is transplanted into adult neocortex, TyrOHase-immunoreactive cells develop and continue to be present in the transplants for the life of the host animal. The percentage of transplant neurons that express TyrOHase is highly correlated with the age of the embryonic donor tissue at the time of transplantation. Many TyrOHase-immunoreactive cells are present in transplants from embryonic day 12 (E12) embryos. The labeled cells are frequently arrayed in striking clusters of cell bodies and their processes, which ramify densely within the transplants. Moderate numbers of cells are found scattered throughout transplants from E14 donors, while E17 donors consistently develop small numbers of TyrOHase-containing cells. Tissue removed for transplantation on the day before birth (E19) never contains cells that express TyrOHase. The TyrOHase-positive cells are mostly bipolar and stellate in shape and show neither immunoreactivity for other catecholamine-synthesizing enzymes nor catecholamine fluorescence. These results provide a demonstration of continued TyrOHase synthesis in central nervous system cells that normally do not express this enzyme. Because of these and similar results with other neurotransmitter enzymes, the transplantation paradigm is particularly useful as a technique for studying the factors that regulate enzyme induction and activity during development of the nervous system.

Simple radiative transfer model for relationships between canopy biomass and reflectance

A modified Kubelka-Munk model has been utilized to derive useful equations for the analysis of apparent canopy reflectance. Based on the solution to the model simple working equations were formulated by employing reflectance characteristic parameters. The relationships derived show the asymptotic nature of reflectance data that is typically observed in remote sensing studies of plant biomass. They also establish the range of expected apparent canopy reflectance values for specific plant canopy types. The usefulness of the simplified equations was demonstrated by the exceptionally close fit of the theoretical curves to two separately acquired data sets for alfalfa and shortgrass prairie canopies.

Reproductive capacity of the mentally retarded

Ninety-seven mentally retarded females were studied to evaluate parameters of growth and development of secondary sex characteristics and the incidence of ovulation. These patients were selected on the basis of age and etiological classification. Patients were classified as Down's syndrome, brain damaged, or undifferentiated. The following parameters of growth and development were studied: anthropometric, bone age, and sexual maturation. Sexual maturation studies consisted of breast development, pubic hair, axillary hair, menarche, menstrual pattern, and ovulatory patterns. The following observations were made from this study: 1. Physical growth and secondary sexual development were retarded in all parameters. 2. The undifferentiated and brain damaged groups showed almost identical patterns of growth and development of secondary sexual characteristics. 3. The Down's syndrome group was the most retarded in physical growth and in secondary sexual development. 4. Skeletal age was a better guide than chronological age or height and body weight to the prediction of development of secondary sex characteristics and age at onset of menarche. 5. In 26 mentally retarded females who had achieved menarche the incidence of ovulation was approximately 60 percent.

Magnetism and Opaque Mineralogy of Basalts from the Mid-Atlantic Ridge at 45° N

The volcanic layer may be only 200 m thick at 45 degrees N and oxidation of titanomagnetite may be responsible for the decrease in amplitude of the magnetic anomalies away from the ridge axis.