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Biomedical subjects

B Horowitz

Publications and source records attributed to B Horowitz.

At least 127 records · Page 7Linked to original sources
PubMed1991

Specific inactivation of viruses which can potentially contaminate blood products.

The viral safety of intramuscular immune globulin and albumin has long been recognized. Safety is the result of multiple barriers operating in concert, including donor selection, donor blood screening, immune neutralization, serendipitous inactivation and removal, and virus sterilization. Experience on the transmission of viruses, most notably hepatitis A and non-A, non-B (HBV and NANBHV) and human immunodeficiency virus (HIV), by coagulation factor concentrates prepared from large plasma pools highlights the difficulty of relying on donor selection and purification methods to eliminate virus transmission and the benefit of potent virucidal procedures. Before virus sterilization, the transmission rate of NANBHV and HIV by these concentrates approached 100%. Following virus sterilization, methods shown to inactivate less than or equal to 10(4) infectious doses (ID50) of hepatitis virus(es) greatly reduced HIV but not NANBHV transmission. Methods shown to inactivate greater than or equal to 10(5) ID50 of hepatitis viruses have eliminated HIV transmission and have greatly reduced hepatitis transmission. Elimination of transmission occurred before HIV and HCV screening and the development of purification methods shown to reduce virus presence. Based on an analysis of the initial virus load, the best coagulation factor concentrates available today are concluded to have a probability of safety equivalent to that of albumin. Introduction of sterilization methodology into the manufacture of all blood protein products should now be considered.

Blood↗
PubMed1990

Differential regulation of Na,K-ATPase alpha 1, alpha 2, and beta subunit mRNA and protein levels by thyroid hormone.

The purpose of this study was to determine the effect of thyroid status on the Na,K-ATPase alpha isoforms and beta in rat heart, skeletal muscle, kidney, and brain at the levels of mRNA, protein abundance, and enzymatic activity. Northern and dot-blot analysis of RNA (euthyroid, hypothyroid, and triiodothyronine-injected hypothyroids = hyperthyroids) and immunoblot analysis of protein (euthyroid and hypothyroid) revealed isoform-specific regulation of Na,K-ATPase by thyroid status in kidney, heart, and skeletal muscle and no regulation of sodium pump subunit levels in the brain. In general, in the transition from euthyroid to hypothyroid alpha 1 mRNA and protein levels are unchanged in kidney and skeletal muscle and slightly decreased in heart, while alpha 2 mRNA and protein are decreased significantly in heart and skeletal muscle. In hypothyroid heart and skeletal muscle, the decrease in alpha 2 protein levels was much greater than the decrease in alpha 2 mRNA levels relative to euthyroid indicating translational or post-translational regulation of alpha 2 protein abundance by triiodothyronine status in these tissues. The regulation of beta subunit by thyroid status is tissue-dependent. In hypothyroid kidney beta mRNA levels do not change, but immunodetectable beta protein levels decrease relative to euthyroid, and the decrease parallels the decrease in Na,K-ATPase activity. In hypothyroid heart and skeletal muscle beta mRNA levels decrease; beta protein decreases in heart and was not detected in the skeletal muscle. These findings demonstrate that the euthyroid levels of expression of alpha 1 in heart, alpha 2 in heart and skeletal muscle, and beta in kidney, heart, and skeletal muscle are dependent on the presence of thyroid hormone.

Animals↗
PubMed1990

Synthesis and assembly of functional mammalian Na,K-ATPase in yeast.

The yeast Saccharomyces cerevisiae was investigated as an in vivo protein expression system for mammalian Na,K-ATPase. Unlike animal cells, yeast cells lack endogenous Na,K-ATPase. Expression of high affinity ouabain binding sites, ouabain-sensitive ATPase activity, or ouabain-sensitive p-nitrophenylphosphatase activity in membrane fractions of yeast cells was observed to require the expression of both alpha subunit and beta subunit polypeptides of Na,K-ATPase in the same cell. High affinity ouabain binding sites are also expressed at the cell surface of intact yeast cells containing both the alpha subunit and the beta subunit of Na,K-ATPase. These observations demonstrate that both the alpha subunit and the beta subunit of Na,K-ATPase are required for the expression of functional Na,K-ATPase activity and that yeast cells can correctly assemble this oligomeric membrane protein and transport it to the cell surface.

Animals↗
PubMed1990

The use of tri(n-butyl)phosphate detergent mixtures to inactivate hepatitis viruses and human immunodeficiency virus in plasma and plasma's subsequent fractionation.

The treatment of plasma with organic solvent/detergent mixtures at the time of plasma collection or pooling could reduce the exposure of technical staff to infectious viruses and enhance the viral safety of the final product. Treatment of plasma for 4 hours with 2-percent tri(n-butyl)phosphate (TNBP) at 37 degrees C, with 1-percent TNBP and 1-percent polyoxyethylensorbitan monooleate (Tween 80) at 30 degrees C, or with 1-percent TNBP and 1-percent polyoxyethylene ethers, (Triton X-45) at 30 degrees C resulted in the rapid and complete inactivation of greater than or equal to 10(4) tissue culture-infectious doses (TCID50) of vesicular stomatitis and Sindbis viruses, which are used as surrogates. Treatment of plasma with TNBP and TNBP and Tween-80 was shown to inactivate greater than or equal to 10(4) TCID50 of human immunodeficiency virus. TNBP treatment of plasma contaminated with 10(6) chimpanzee-infectious doses (CID50) of hepatitis B virus and 10(5) CID50 of non-A,non-B hepatitis virus prevented the transmission of hepatitis to chimpanzees. Immediately after treatment of plasma with 2-percent TNBP, the recovery of factors VIII, IX, and V and antithrombin III was 80, 90, 40, and 100 percent, respectively. Recovery of all factors was greater than or equal to 90 percent after treatment with TNBP and detergent mixtures. Treated plasma was fractionated by standard techniques into antihemophilic factor and prothrombin complex concentrates, immune globulin, and albumin. Prior treatment with TNBP or TNBP and detergent did not affect the separations of desired proteins. Therefore, it appears possible to inactivate viruses in plasma before the execution of standard fractionation procedures.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Proteins↗
PubMed1990

Improvement in plasma protein concentrations with fibronectin treatment in severe malnutrition.

Severely malnourished young children (n = 72) were treated with intravenous fibronectin to assess its efficacy as an adjunct treatment for kwashiorkor and/or marasmus. The protein was given in a double-blind study during the first 4 d of hospitalization together with standard nutrition and supportive therapy. Fibronectin concentrations as well as albumin, transferrin, prealbumin, and alpha-2-macroglobulin were monitored in samples taken before each dose of fibronectin and in samples taken five times thereafter. Sick individuals had significantly lower concentrations of all five proteins than did healthy control individuals of matching ages. Mean fibronectin concentrations were 98 +/- 7 mg/L (mean +/- SEM) for sick vs 303 +/- 21 mg/L for healthy individuals. Concentrations of all five proteins increased at a greater daily rate in patients treated with fibronectin than in patients who received placebos. Eighty-seven percent of the treated children survived to the end of the treatment and observation periods (mean hospitalization 14.7 d) whereas only 56% of the control subjects survived (P = 0.004). These data support the use of intravenous fibronectin as an adjunct in the treatment of severe malnutrition at a dosage of 7.5 mg.kg-1.d-1 over a 4-d period.

Blood Proteins↗
PubMed1989

The influence of fibronectin administration on the incidence of sepsis and septic mortality in severely injured patients. The Medical College of Georgia Fibronectin Research Group.

Eighty-five trauma patients between the ages of 18 and 55, with American College of Surgeon's (ACOS) trauma scores greater than or equal to 7 were entered into a double-blind, randomized, placebo-controlled study to assess the efficacy of prophylactic fibronectin (Fn) administration on clinical course, sepsis development, and septic mortality. Patients were randomized on admission to receive purified human virus-inactivated Fn or placebo control (human serum albumin, HSA). Fn or HSA was administered on a daily basis if and when the patient was Fn deficient (less than 75% normal). When a Fn deficiency was not evident, the patient received saline. Seventy one patients developed Fn deficiencies during their initial clinical course: 36 received Fn, 35 received HSA. Fourteen patients did not develop a Fn deficiency after trauma and thus received only saline. Analysis of admission data demonstrated no significant differences between the three groups with respect to extent of injury (injury severity score, ACOS trauma score) or physiologic assessments of organ function (serum creatinine, bilirubin, lactic acid). On day 1 after trauma, Fn levels were shown to correlate with other plasma proteins and cellular components (range of r values, 0.24 to 0.75; all p less than 0.05), but not with organ function parameters. Eighteen of 85 patients became septic as judged by clinical criteria. Ten of these patients had received Fn (10 of 36), five had received HSA (5 of 35), and three had received only saline (3 of 14) before the development of sepsis (differences not significant). When septic, nine of 17 patients developed Fn deficiencies. Six patients received Fn while septic, three received albumin, and eight received saline. Seven patients died: 5 of 6 Fn patients, 1 saline, and 1 HSA recipient. Our data suggest that exogenous Fn repletion in states of deficiency does not alter clinical course, the development of sepsis, or septic mortality.

Adolescent↗
PubMed1989

Acute renal failure following cocaine abuse.

Three healthy adult males developed acute renal failure following cocaine abuse. Muscle pain, tenderness, elevated levels of serum muscle enzymes, heme-positive urine and the presence of pigmented granular casts in urine all indicated occurrence of rhabdomyolysis. One of them developed acute compartmental syndrome of the left leg and required emergency fasciotomy. The course of renal failure and fast recovery were suggestive of acute tubular necrosis in all 3 patients. A possible role of cocaine in the aggravation of renal and/or muscle ischemia has been speculated.

Acute Kidney Injury↗
PubMed1988

Virus safety of solvent/detergent-treated antihaemophilic factor concentrate.

The safety of an antihaemophilic factor concentrate treated with the organic solvent tri-(n-butyl)phosphate and sodium cholate (factor VIII-SD) was assessed for transmission of non-A, non-B (NANB) hepatitis and human immunodeficiency virus (HIV). Patients enrolled in the study had no previous exposure to blood products made from plasma pools, although 5 had received small quantities of single-donor products. All but 1 had normal alanine aminotransferase (ALT) levels, none had markers of HIV infection, and all had been vaccinated against hepatitis B. After treatment with factor VIII-SD, serum ALT levels and HIV antibody were monitored for up to 1 year. 20 patients received 625 to greater than 40,000 U (total 163,000 U, median dose 3900 U), and 17 of these were followed up for at least 6 months: transmission of either NANB hepatitis or HIV was not observed.

Adolescent↗
PubMed1988

Failure of a human immunodeficiency virus (HIV) immune globulin to protect chimpanzees against experimental challenge with HIV.

To assess the possible efficacy of passive immunization against human immunodeficiency virus (HIV) an immune globulin was prepared from plasma of HIV-seropositive donors selected to be among those having the top 12.5% of virus-neutralizing antibody titers. The immune globulin was treated with pepsin to render it intravenously tolerable. The preparation, which we termed HIVIG, neutralized 100 tissue culture 50% infective doses (TCID50) of HIV at an average dilution of 1:1000 in neutralization tests in vitro. During preparation HIVIG was subjected to virus inactivation and removal procedures that in theory resulted in a reduction in HIV infectivity by a factor of 10(25). At a dose of 9-10 ml/kg of body weight both the virus-inactivated source plasma and the final immunoglobulin preparation were noninfective and without adverse effect in two chimpanzees. Two chimpanzees inoculated intravenously with HIVIG at 1 ml/kg and two inoculated with 10 ml/kg were challenged intravenously 1 day later with 400 TCID50 of the same strain of HIV (HTLV-IIIb) used in neutralization assays in vitro. All animals became infected. Incubation periods to virus isolation (by cocultivation with human mononuclear cells) in HIVIG recipients did not differ significantly from the incubation period seen in a control animal that received a normal anti-HIV-free immunoglobulin. These findings may have implications for understanding the failure of experimental vaccines to protect against HIV challenge in chimpanzee experiments.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Inactivation of lipid-enveloped viruses in labile blood derivatives by unsaturated fatty acids.

Virus sterilization of blood plasma derivatives by addition of several naturally occurring fatty acids was evaluated using vesicular stomatitis virus and Sindbis virus as markers for lipid-enveloped virus inactivation and human immunodeficiency virus (HIV). Inactivation of greater than or equal to 10(4) tissue culture infectious doses (TCID50) of marker viruses added to antihemophilic factor (AHF) concentrates, with 60-100% retention of AHF activity, was achieved with oleic, 11-eicosenoic, linoleic, linolenic, palmitoleic and arachidonic acids. Elaidic, gamma-linolenic, palmitic, and arachidic acids and another fat-soluble compound previously reported to inactivate virus, butylated hydroxytoluene, were less effective. A long chain mono- but not a di- or triglyceride also displayed virucidal properties. Evaluation of the inactivation of HIV added to an immune globulin solution on exposure to 0.033% sodium oleate for 20 min indicated inactivation of greater than or equal to 10(3.4) TCID50. The degree of virus inactivation depended on the sample composition. A favorable balance was achieved between degree of virus inactivation and retention of protein function for AHF concentrate, prothrombin complex concentrate, antithrombin III concentrate, and immune globulin solution on incubation with 0.033% (w/v) sodium oleate at 24 degrees C for 4-6 h. Virus inactivation in whole plasma and plasma cryoprecipitate was not complete despite use of higher concentrations of sodium oleate and/or incubation at 37 degrees C. Reduced virus kill in these less purified derivatives probably is a consequence of their endogenous lipid and/or albumin.

Antiviral Agents↗
PubMed1988

Thyroid hormone coordinately regulates Na+-K+-ATPase alpha- and beta-subunit mRNA levels in kidney.

Synthesis of the sodium pump, Na+-K+-ATPase, is regulated by thyroid hormone in responsive tissues. The purpose of this study was to determine if triiodothyronine (T3) regulates the concentration of the mRNAs coding for the two enzyme subunits, alpha and beta, and the time course of the response. A single dose of T3 (250 micrograms/100 g body wt) was administered to hypothyroid rats that were killed at various times after injection. In the kidney cortexes of the T3-injected animals, as well as hypothyroid and euthyroid rats, alpha- and beta-mRNA concentrations were measured by dot blot using cDNAs corresponding to the two mRNAs; alpha-subunit abundance was measured by Western blot using antibodies to the enzyme, and Na+-K+-ATPase activity was measured enzymatically. alpha- and beta-mRNAs increased coordinately, after a 6-h time lag to 1.6-fold over hypothyroid levels by 12 h after T3. alpha-Subunit abundance increased significantly by 48 h and to 1.4-fold over hypothyroid by 72 h after T3. Na+-K+-ATPase activity increased with the same time course as the increase in alpha-subunit abundance to 1.3-fold over hypothyroid by 72 h after T3. We conclude that T3 regulates Na+-K+-ATPase synthesis and activity by coordinately increasing the mRNAs of both the alpha- and beta-subunits of the enzyme.

Animals↗
PubMed1988

Development of a heterologous gene expression system for the Na,K-ATPase subunits in the yeast Saccharomyces cerevisiae.

cDNA fragments coding for the alpha and beta subunits of the Na,K-ATPase were separately ligated into the yeast expression vector YEp1PT in both the sense (YEpNKA(+)) and anti-sense (YEpNKA(-)) orientations with respect to the promoter. The recombinant plasmids were introduced into Saccharomyces cerevisiae strain UT4 by transformation. Total RNA from the transformed strains was isolated and analyzed by Northern hybridization. The resulting autoradiogram revealed strong signals indicative of a high level of transcriptional expression of both subunits in both orientations of the cDNA. 35S-Methionine labeled extracts were immunoprecipitated with antibodies specific for the beta subunit. A beta subunit translation product was produced from YEp beta NKA(+) but not from YEp beta NKA(-). Experiments to detect an alpha specific translation product are in progress.

Animals↗
PubMed1988

Acute interstitial nephritis following enterobacteriaceae sepsis.

A 52-year-old male developed acute renal failure (ARF) following enterobacteriaceae sepsis. The cause of renal failure was remarkable for prolonged, slow, and incomplete recovery. Recurrence of enterobacteriaceae infection was associated with fever, cutaneous rash, eosinophilia, and elevated IgE level. Renal biopsy and gallium scan studies confirmed the diagnosis of acute interstitial nephritis. The temporal relationship between the first episode of sepsis and the precipitation of ARF and the development of rash, eosinophilia, and elevated IgE level in association with recurrence of infection indicated the role of bacterial antigen in the induction of immune-mediated injury.

Dermatitis, Atopic↗
PubMed1987

Molecular cloning and sequence analysis of the (Na+ + K+)-ATPase beta subunit from dog kidney.

cDNA complementary to mRNA coding for the beta subunit of dog renal (Na+ + K+)-ATPase has been cloned into lambda gt11 and the nucleotide sequence of the DNA has been determined. The amino acid sequence of the beta subunit polypeptide has also been deduced from the DNA. The mature form of the dog kidney beta subunit contains 302 amino acids with three potential asparagine-linked attachment sites for carbohydrate. The initiation methionine is removed during processing of the polypeptide to its mature form. Although the beta subunit is an integral membrane protein there is no signal sequence for the polypeptide, and hydropathy analysis predicts that the beta subunit polypeptide spans the cell membrane only once. Secondary structure predictions and a model for the structure of the beta subunit are proposed. DNA sequencing of the 5' non-coding region of the mRNA revealed a 200 bp inverted repeat from the coding region. Blot hybridization of a fragment of the beta subunit cDNA identified a single mRNA species of 2.7 kb in dog kidney and several rat tissues. RNA from rat liver was deficient in mRNA that hybridized to the dog kidney beta subunit cDNA, although mRNA that hybridized to an alpha subunit cDNA was detected. RNA from a human hepatoma cell line, HepG2, however, contained comparable levels of mRNA for both the alpha and the beta subunits.

Amino Acid Sequence↗