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Biomedical subjects

S A Weinstein

Publications and source records attributed to S A Weinstein.

At least 37 records · Page 2Linked to original sources
PubMed1990

Thermophysiologic anthropometry of the face in Homo sapiens.

Standard clinical thermographic practice has been to regard a side-to-side skin surface temperature difference of 0.5 degrees C or greater as indicative of a clinically significant disorder when such a difference is observed for the contralateral sides of the face. Prior to this time this standard relied upon empiric observation and cumulative experience. This paper provides the first published documentation clearly supportive of this long-standing clinical practice.

Cephalometry↗
PubMed1988

Isolation of a hemolysin from a spore-crystal mixture of Bacillus thuringiensis israelensis (serotype H-14).

A hemolytic toxin from Bacillus thuringiensis israelensis was obtained by alkaline extraction and fast protein liquid chromatography (chromatofocusing followed by gel filtration). The toxin displayed a pI of 4.6-4.8 and an Mr of 26,000. Amino acid analysis demonstrated large amounts of serine, glycine and glutamic acid. The toxin was strongly lytic for rabbit, human and non-human primate erythrocytes, and was weakly lytic toward equine, feline, canine, bovine, amphibian and reptilian erythrocytes. It was weakly entomocidal as indicated by a lethal potency (LC50) of 25 micrograms/ml for second instar larvae of Anopheles stephansi. Direct micro-ELISA indicated that the toxin lacked antigenic identity with numerous eukaryotic and prokaryotic toxins and venoms.

Amino Acids↗
PubMed1988

Kinetics of hemolysis induced by a toxin from Bacillus thuringiensis israelensis.

The kinetics of hemolysis resulting from the action on rabbit erythrocytes of a highly purified cytolytic toxin (26,000 mol. wt) isolated from a spore-crystal mixture of Bacillus thuringiensis israelensis was studied. Course of hemolysis, as determined by release of hemoglobin, yielded sigmoid curves whose maximum slopes were taken as a measure of the rate of lysis. Hemolysis occurred without an induction period, and the rate of lysis was a linear function of toxin concentration. Rate of hemolysis as a function of temperature yielded an Arrhenius constant of 9300 calories per mole. The toxin was active between pH 4.5 and 8.0. Lysis was strongly inhibited by Cu2+, Fe2+ and Zn2+ in concentrations as low as 0.025 M. Phosphatidylserine, phosphatidylinositol, phosphatidylcholine and sphingomyelin inhibited lysis, whereas phosphatidylethanolamine, cerebroside, cholesterol and major integral erythrocyte membrane proteins caused little or no inhibition. Inhibition of lysis by sucrose indicates that hemolysis is of the colloid-osmotic type.

Bacillus thuringiensis↗
PubMed1987

Isolation and characterization of a phospholipase B from venom of Collett's snake, Pseudechis colletti.

Phospholipase B in the venom of the Australian elapid snake, Pseudechis colletti, was purified to near homogeneity. By means of gel filtration it had an Mr of about 35,000, and by SDS-polyacrylamide gel electrophoresis an Mr of about 16,500. These presumably are dimeric and monomeric forms of the enzyme. It was isoelectric at pH 6.2 as compared to 7.8 for phospholipase A2 from which it was readily separated. It was relatively thermostable. As determined by release of water-soluble phosphorous, it degraded phosphatidylcholine and phosphatidylethanolamine, but did not degrade other phospholipids tested. The purified enzyme was strongly hemolytic in vitro for rabbit and human erythrocytes, but not for bovine or ovine erythrocytes. Hemolysis of rabbit erythrocytes gave rise to membranes showing ultrastructural changes that may be unique for this enzyme. The protein was highly active in producing turbidity in dilute solutions of egg yolk. It was cytotoxic for cultured rhabdomyosarcoma cells and was lethal for mice in which death was preceded by massive myoglobinuria.

Animals↗
PubMed1987

Nursing assessment program in infection control procedures.

To assess the infection control educational needs of the nursing service while providing a "hands-on" in-service exercise, nurses were invited to test their infection control knowledge as part of a clinical scenario. After a brief review of the "case," participants surveyed for 10 minutes a mock patient's room where a manikin served as the "patient." Through staged breaks in technique, various components of infection control practice were to be identified by the participants. Five basic areas of infection control practice including handwashing and isolation technique, Foley catheter care, intravenous therapy and line maintenance, use of suctioning equipment and fluids, and general sanitation were presented at 12 stations within the room. Immediately after this exercise, members of the infection control staff revealed the errors in the exhibit and demonstrated the correct procedures. The average score among 548 participants was 57% (11.4 out of 20 possible correct answers). Scores were not influenced by the number of years of experience in nursing. However, differences were seen regarding educational degree and nursing units, which served as a basis to recommend specific infection control education.

Antisepsis↗
PubMed1986

Isoelectric analysis of some Australian elapid snake venoms with special reference to phospholipase B and hemolysis.

Venoms of the Australian elapid snakes Austrelaps superbus and Pseudechis colletti were analyzed in an electrofocusing column. A. superbus venom, little studied in the past, was found to have a mouse i.p. lethal potency of 0.48 mg/kg and to contain at least four lethal components. Venoms of both species had relatively high direct hemolytic activity for washed rabbit erythrocytes, as contrasted with venoms from 23 other species of snakes that were not hemolytic under the conditions used. Among venoms of the same 25 species, those of A. superbus and P. colletti produced turbidity in diluted egg yolk, those of Bungarus caeruleus and Bungarus multicinctus were quantitatively less active on egg yolk, whereas venoms of the 21 remaining species were negative. The component of the venoms responsible for egg yolk reactivity was partially purified and the preparations obtained were strongly active when tested with diluted egg yolk or with erythrocytes. Thin layer and paper chromatographic studies showed that these preparations possessed phospholipase B activity for phosphatidylcholine, lysophosphatidylcholine, phosphatidylethanolamine and phosphatidylserine, but sphingomyelin was not degraded. The results suggest that hydrolysis of phosphatidylcholine is responsible for both egg yolk reactivity and hemolysis.

Animals↗
PubMed1986

Geographic and ontogenic variation in venom of the western diamondback rattlesnake (Crotalus atrox).

Venom samples from western diamondback rattlesnakes (Crotalus atrox) from 13 localities in the United States were tested for i.v. and s.c. lethality for mice, protease activity, hemorrhagic activity, and the presence of Mojave toxin. Electrophoresis on polyacrylamide gel was used to compare protein composition. The neutralizing effect of two commercial antivenoms was evaluated against selected samples of venom. Venom of young snakes from north Texas was compared with that of adults from the same locality. Venom samples from the southwest portion of the range showed highest lethality, those from the northeast portion lowest. This trend was reversed with respect to protease activity. Hemorrhagic activity showed little geographic variation, but northern samples tended to be slightly higher. Differences in venom protein composition were evident between snakes from the eastern and western portions of the range. Mojave toxin in small to trace amounts was detected in two Arizona venom samples and one from west Texas. Antivenoms were relatively ineffective in neutralizing lethality. Venom of young snakes from north Texas was much more lethal by s.c. injection than that of adult snakes from any part of the range, but very low in protease activity. Hemorrhagic activity was about equal to that of adult snakes from the same region. Fifteen months later, lethality had declined almost five-fold, and protease activity had approached adult levels. There was a distinct change in protein composition. Mojave toxin was not detected in venoms of the young snakes.

Animals↗
PubMed1985

The distribution among ophidian venoms of a toxin isolated from the venom of the Mojave rattlesnake (Crotalus scutulatus scutulatus).

A toxin analogous to Mojave toxin or protein K' was isolated from venom of the Mojave rattlesnake (Crotalus s. scutulatus) by anion exchange and gel permeation chromatography. This toxin has an apparent native molecular weight of 20,000-22,000, a subunit molecular weight of 14,000 and a pI of 4.9-5.0. The i.p. LD50 is 0.094 mg/kg for mice. A wide variety of ophidian venoms (crotaline, viperine, elapid, hydrophid and colubrid) were examined for the presence of this toxin using Ouchterlony, immunoelectrophoresis, ELISA and Western transfer. High concentrations were found in 4 of 6 C. scutulatus venom samples, 2 of 3 C. durissus samples and samples from C. viridis concolor and C. tigris. A moderate concentration was found in 1 of 3 C. durissus samples and low to trace concentrations in 1 C. durissus sample, 1 C. scutulatus sample, 2 of 12 C. atrox samples and a Trimeresurus flavoviridis sample, the latter being the only instance of detection of the toxin in a snake other than a rattlesnake. The toxin appears in at least two phylogenetic lines of rattlesnakes, and its geographic distribution in North American rattlesnake species resembles a mosaic.

Animals↗
PubMed1985

Disposable needle and syringe containers.

Needle/syringe disposal in health care facilities should comply with current CDC, JCAH, and EPA recommendations. Most state laws require that needle/syringes be rendered inoperable for future use. However, this does not necessarily mean that needles have to be broken or bent. Needles/syringes that are placed in a puncture and leak-proof container that are eventually autoclaved or incinerated should satisfy the intent of these regulations. It must be emphasized that currently no data are available from controlled studies examining the effect, if any, of these devices on the incidence of needle-transmissible infections. However, common sense dictates that the new disposable containers are easier and safer to use and therefore should contribute to decreasing the incidence of needle puncture accidents among health care workers. A comprehensive program aimed at minimizing needle-stick accidents should address not only disposal devices and their accessibility at key locations, but also periodic inservice education.

Disposable Equipment↗
PubMed1984

Lethal potencies and immunoelectrophoretic profiles of venoms and Vipera bornmulleri and Vipera latifii.

Lethality determinations are reported for Vipera bornmulleri and V. latifii. V. latifii venom is significantly more toxic than V. bornmulleri by the i.v. route; by the i.p. and s.c. routes there is little difference between the species. Immunoelectrophoretic profiles indicate close antigenic relationship between venoms of these species and V. palaestinae and Bitis spp.; a more remote relationship with V. russelli and Echis carinatus. Protease activity of V. latifii venom is stronger than that of V. bornmulleri.

Animals↗
PubMed1984

Protease activity and lethal toxicity of venoms from some little known rattlesnakes.

Information on yield, lethality, and protease activity is given for venoms of Crotalus exul, C. p. pricei, C. pusillus, C. w. willardi and Sistrurus ravus. Lethal toxicity of C. tigris venom (LD50 i.v. 0.056 mg/kg; s.c. 0.21 mg/kg) is the highest known for any rattlesnake venom. The lethal potency of C. pricei venom is high by i.v. but not by s.c. injection. Both these venoms lack protease activity. C. pusillus venom is lowest in lethality.

Animals↗
PubMed1984

An enzyme-linked immunoassay for detection of North American pit viper venoms.

We describe a method for immunodetection of North American pit viper venoms in clinical materials. Antibody-enzyme conjugates prepared against venoms of the western diamondback rattlesnake (Crotalus atrox), Mojave rattlesnake (Crotalus scutulatus), and copperhead (Agkistrodon contortrix) detect homologous venoms in concentrations of 0.1-.01 mcg/ml using a double antibody sandwich technique. Venoms of 10 additional species of U.S. pit vipers were detected in concentrations of 10 mcg/ml or less. Venoms of 4 species could not be detected at levels likely to be encountered in clinical situations. There are extensive cross-reactions between venoms of certain species, hence specific identification of a given venom cannot always be made. Venom usually can be detected at injection sites of experimental animals receiving intramuscular doses of 0.5-1.5 mg of venom but can rarely be detected in urine or plasma specimens. Venom was readily detected in specimens from experimental animals bitten by pit vipers of 6 species. The method is relatively rapid, simple, and inexpensive.

Animals↗