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Biomedical subjects

J Margolis

Publications and source records attributed to J Margolis.

At least 19 recordsLinked to original sources
PubMed1992

Rapid and automated characterisation of seed genotype using Micrograd electrophoresis and pattern-matching software.

New precast microgels are described for use in quickly identifying seed of cereal varieties by determining protein composition within an hour. For example, gliadin proteins are extracted from crushed wheat grain, wheatmeal or flour with ethylene glycol (centrifugation not necessary) and 5 microliters extract is applied to a Micrograd gel (3-15% gel gradient) for ten minutes' electrophoresis at 300 volts in sodium lactate buffer (pH 3.1). Alternatively, precast gels are available for SDS gel electrophoresis for examining a different aspect of grain composition as a means of identification. To further expedite identification, software packages have been developed to match the protein pattern for an unknown sample against those of authentic samples, thus to provide quick and definite identity, based on electrophoretic banding, densitometer scan, HPLC profile, multiple antibody reaction or RFLP pattern (PatMatch program). Furthermore, the program WhatWheat offers advice on the best combination of methods to use for a specific task of identification.

Automation↗
PubMed1992

Rapid (ten-minute) pore-gradient electrophoresis of proteins and peptides in Micrograd gels.

Precast gradient gels of short migration length (25 mm) have been developed to provide rapid electrophoretic separation without loss of resolution. These Micrograd gels have been prepared in gel ranges (conventional and unique) to match pore-gradient electrophoresis conditions to proteins/peptides ranging in size from several hundreds to millions. The Hylinx Micrograd gel combines an extreme gel range (6 to 48% polyacrylamide) with a novel crosslinker to provide sieving of polypeptides, and pore-limit electrophoresis of the smallest proteins (e.g. insulin monomer). All gel ranges (such as 3 to 30%) provide zone sharpening in routine analysis of conventional protein mixtures (e.g. serum) within 10 min electrophoresis at 200 to 300 volts. The gels are thin (1 mm) and thus stain quickly, but the gel cassette is of conventional overall width (83 mm), thus fitting many apparatus designs and accommodating 12 samples. The gels are finding valuable use in screening applications, requiring the electrophoretic analysis of many samples, and in cases where a rapid answer is needed, such as monitoring protein purification. The gels have proved particularly useful, in-house, for the latter application in developing Gradipore's new large-scale preparative electrophoresis system, the Gradiflow.

Electrophoresis, Polyacrylamide Gel↗
PubMed1987

Prolonged beneficial effects of dobutamine in refractory heart failure--case histories.

Two patients with refractory congestive heart failure were treated with dobutamine for forty-eight to seventy-two hours with close monitoring of weight and symptomatology. After two to four cycles of dobutamine treatment, 1 patient showed sustained hemodynamic benefit after six months, whereas the second patient had partial improvement. At the end of a one-year follow-up, both had sustained improvement in effort tolerance, documented by a stress test. The quality of life has markedly improved, and they have not required further hospital care.

Dobutamine↗
PubMed1987

Freeze-dried activated substrate for factor VIII assays.

Factor VIII-deficient plasma (natural or artificial) mixed with kaolin and phospholipid can be lyophilized to provide ready-to-use substrate which is stable for months at 4 degrees C and usable after many weeks at room temperature. Factor VIII assays are much simplified and more reproducible using this reagent and can be quantified with the aid of a programmable calculator according to the equation (formula; see text) as % of standard and X, S and B are clotting times of test, standard and blank samples respectively. The slope of the log/log function (k) is approximately--6.5.

Blood Coagulation Tests↗
PubMed1987

The telephone management of gastroenteritis by family medicine residents.

In order to describe the telephone management of gastroenteritis by family practice residents, audiotapes and transcripts of telephone calls by 31 family practice residents were analysed with respect to clinical content, temporal patterns, and physicians' utterance form. The study hypothesis were that year 3 residents would have shorter calls, take more complete histories, and score better on other performance measures than year 1 residents, but no significant differences were demonstrated in the study. The mean duration of telephone calls was 4.6 minutes. Residents talked three times longer than the caller. History taking completeness was highly correlated with telephone call duration and particularly with time spent talking by the caller. Significant questions, such as asking about hydration status, were frequently omitted. Most questions were closed (84 percent). Time spent talking by the caller was longer, and more listener feedback was given, with year 1 than with year 3 residents.

Child, Preschool↗
PubMed1986

Preparation of stable lyophilized cryoprecipitate in the original frozen plasma bags.

A procedure for preparing single units of freeze-dried cryoprecipitate (cryo) in the original bags is described in detail. Batches of frozen plasma bags were rapidly thawed by rocking in a water bath, centrifuged and after complete removal of supernate the compact cryo pellets (2-5 g) were lyophilized with the aid of a holding tray with a filtered air chamber designed for this purpose. Adding synthetic amino acids has greatly improved stability of the dried concentrate during storage and has increased its resistance to heat denaturation (e.g. less than 10% loss of potency after 20 h at 70 degrees C). The method is presented as a viable option for safe and economical manufacture of a stable factor VIII concentrate.

Blood Preservation↗
PubMed1985

Human placental alkaline phosphatase in liver and intestine.

Three distinct forms of human alkaline phosphatase, presumably isozymes, are known, each apparently associated with a specific tissue. These are placental, intestinal, and liver (kidney and bone). We have used a specific immunoassay and HPLC to show that placental alkaline phosphatase is also present in extracts of liver and intestine in appreciable amounts.

Alkaline Phosphatase↗
PubMed1984

A process for preparation of 'high-purity' factor VIII by controlled pore glass treatment.

A simple process for large-scale manufacture of 'high-purity' factor VIII is described in detail. A crude concentrate prepared from washed cryo is treated with controlled pore glass (CPG, 500 A pore diameter) in proportion of 20-30 ml of CPG to 1 g input of protein. The slurry is poured into a separation column and the effluent purified concentrate collected. The remaining factor VIII in the void volume is displaced by a wash solution. After passage through a 0.2 micron membrane filter the product is dispensed and lyophilized. Maintaining the operating pH at 6.5-6.7 and adding synthetic amino acids improved the yield and solubility. The current concentrate contains 1 unit of factor VIII per mg protein (10 units mg fibrinogen) with a recovery of 250 units/kg plasma. The CPG stage is non-destructive, yielding more than 90% of the input factor VIII. In 1980-1983, more than 3 X 10(6) units have been used in New South Wales, mostly for massive cover in surgical patients. In collaboration with the Commonwealth Serum Laboratories, it is intended to expand production for use in other Australian States.

Amino Acids↗
PubMed1983

Electrophoresis of small proteins in highly concentrated and crosslinked polyacrylamide gradient gels.

A high concentration (40%) of acrylamide plus N,N'-methylenebisacrylamide combined with a high level of crosslinking (12.5%) yielded clear gels capable of restricting the passage of small proteins. This gel composition was chosen in preference to other combinations, in particular those producing opaque gels which have larger pore sizes and which provide a reduced sieving effect. Gradient gels were prepared in which the gel concentration rose from 3 to 40% and the degree of crosslinking increased from 4 to 12.5%. Such gels were suitable for fractionating crude, unreduced, and uncharacterized extracts containing proteins ranging in molecular size from 10,000 to several million daltons under conditions where all proteins are retained on the gel even after prolonged electrophoresis. The gels yielded zones which were of improved sharpness and resolution compared with gels of lower concentration and degree of crosslinking, and can be used to provide an estimate of molecular size. Examples of the use of HX gradient gels included both anodic and cathodic electrophoresis at pH 8.3 and 3.1, respectively, of serum and cereal-grain proteins and a partial enzymic hydrolysate of serum albumin.

Acrylamides↗