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At least 19 recordsLinked to original sources

PubMed1978

Commercial national board review programs. A case study at the Medical College of Georgia.

For a long period, students have been taking national board examination review programs offered by commercial firms. The one question to which faculty and students would like the answer is, "Do the national board review programs offered by these commercial firms do any good?" Events at the Medical College of Georgia have provided an opportunity to gather data toward an answer to this question. In 1976, thirty-three medical students at the Medical College of Georgia enrolled in a commercial national board review program. Performance of these students was compared with the predicted performance of these students had they not taken the national board review program. The results suggest that the commercial review program did not notably help these students.

Education, Medical↗

PubMed1979

Suitability of commercial control sera for the quality control of activity determination of alkaline phosphatase.

The suitability of thirteen commercially available control sera for measuring alkaline phosphatase (EC 3.1.3.1; orthophosphoric acid monoester phosphohydrolase, ALP) activity in human serum was tested. Apart from differences in ALP activity observed in some reconstituted commercial sera, the behaviour of control materials towards experimental variables such as the nature and concentration of the substrate, pH and type of buffer (or PO4-acceptor) together with the composition of the isoenzymes present in human serum highlights the problems and difficulties if commercial materials are to be used as control sera. The half-saturation constants in control sera were in all cases smaller than those of ALP isoenzymes from bone and liver. The shape of substrate activity curves and the pH optimum in most of control sera differed from that of human serum. The discrepant kinetic data of control materials and human serum may mask or suggest changes relevant to commercial quality control serum but not to samples of human serum.

Alkaline Phosphatase↗

PubMed2025

Autologous Fibrin Glue in Pterygium Surgery as an Alternative to Commercial Fibrin Glue.

PURPOSE: The aim of this study was to evaluate the efficacy and safety of autologous fibrin glue in pterygium surgery, comparing it with commercial fibrin glue in terms of postoperative complications, graft stability, and recurrence rate. METHODS: A prospective, randomized, double-blind study was conducted, involving 42 patients with primary pterygium who underwent autologous conjunctival-limbal transplantation. The graft was fixed using autologous fibrin glue (Group 1, G1) or commercial fibrin glue (Group 2, G2). All patients underwent surgery performed by the same surgeon and were reevaluated on postoperative days 7, 30, 90, and 180 by an independent observer, assessing clinical parameters in the preoperative, intraoperative, and postoperative periods. RESULTS: No cases of severe adverse events were reported. Complete graft dehiscence occurred in 1 patient from G1. The G2 group had more cases of subconjunctival hemorrhage ( P = 0.0355). Pyogenic granuloma was observed in 1 patient from G2 and 2 patients from G1. There was no significant difference in recurrence rates between the groups (15% in G1 vs. 5% in G2; P = 0.2918). In both groups, graft dimensions tended to decrease slightly in the early postoperative period, followed by stabilization. CONCLUSIONS: Autologous fibrin glue demonstrated efficacy and safety comparable to commercial fibrin glue, making it a viable alternative to conjunctival graft fixation in primary pterygium surgery.

Humans↗

PubMed1975

Interaction of Clostridium perfringens theta-haemolysin, a contaminant of commercial phospholipase C, with erythrocyte ghost membranes and lipid dispersions. A morphological study.

Commercially available preparations of phospholipase C from Clostridium perfringens are commonly contaminated with theta haemolysin, one of a group of bacterial haemolysins called oxygen labile (O-labile) haemolysins. Treatment of erythrocyte ghosts and a mixed lipid dispersion containing cholesterol with commercially available phospholipase C in the absence of Ca-2+ and the presence of phosphate buffer and/or EDTA resulted in the formation and release of ring or arc-shaped structures. Highly purified phospholipase C, free of theta-haemolysin, produced no changes in the morphology of erythrocyte ghosts or lipid dispersions in the presence of phosphate or EDTA, but caused the formation of typical diglyceride droplets in the presence of Ca-2+ in the absence of these inhibitors. Ring structures, identical to those caused by commercial phospholipase C, were formed on addition of highly purified theta-haemolysin to erythrocyte ghost membranes, lipid dispersions containing cholesterol and cholesterol dispersions, but not on treatment of membranes from Micrococcus lysodeikticus. Heat-inactivated O-haemolysin (60 degrees C for 10 min) produced no such effects. The dimensions of rings and arcs displayed heterogeneity. The outside diameters in various preparations varied from approx. 27-58 nm with border thickness of 4.1-7.8 nm.

Binding Sites↗

PubMed1978

The fatty acid content and drug binding characteristics of commercial albumin preparations.

The fatty acid contents of thirteen commercial preparations of human albumin were found to be in the range 0.03 to 9 mol of fatty acid/mol albumin. Marked differences were found between the preparations in the binding of the fluorescent probes, 5-dimethylamino-naphthalene-1-sulfonamide (DNSA) and dansylsarcosine. The displacement of these probes by ibuprofen and phenylbutazone also showed marked differences between preparations. The differences between the commercial albumin samples correlated well with their fatty acid contents and were abolished by treatment with charcoal. They were similar to the changes observed when oleic acid was added to fatty acid free albumin. The source and fatty acid content of commercial albumin preparations should be considered when comparing studies of the binding of drugs to human albumin.

Fatty Acids↗

PubMed1976

Purification and characterization of commercial NADH and accompanying dehydrogenase inhibitors.

The anion-exchange chromatography of commercial NADH using a potassium bicarbonate solution as eluent yields highly pure NADH with good stability. Twelve compounds are also separated which act as dehydrogenase inhibitors. The main impurities are further characterized. The compound mainly responsible for residual optical density in commercial NADH preparations is probably a stereoisomer of NADH which is in reversible equilibrium with NADH at pH values in the range 5-7. A method of thin-layer chromatography, to check commercial NADH preparations for impurities, is described.

Bicarbonates↗

PubMed2025

Systematic comparison of quantity and quality of RNA recovered with commercial FFPE tissue extraction kits.

BACKGROUND: FFPE tissue samples are commonly used in biomedical research and are a valuable source for next-generation sequencing in oncology, however, extracting RNA from these samples can be difficult the quantity and quality achieved can impact the downstream analysis. This study compared the effectiveness of seven different commercially available RNA extraction kits specifically designed for use with FFPE samples in terms of the quantity and quality of RNA recovered. METHODS: This study used 9 samples of FFPE tissue from three different types of tissue (Tonsil, Appendix and lymph node of B-cell lymphoma) to evaluate RNA extraction methods. Three sections of 20 µm of each sample were combined per sample. The slices were distributed in a systematic manner to prevent any biases. Each of the 7 commercially available RNA extraction kits were used according to manufacturer's instructions, with each sample being tested in triplicate resulting in a total of 189 extractions. The concentration, RNA quality score (RQS) and DV200 of each extraction was analysed using a nucleic acid analyser to determine the quantity and quality of the recovered RNA. RESULTS: This study found that despite processing the FFPE samples in the same standardized way, there were disparities in the quantity and quality of RNA recovered across the different tissue types. Additionally, the study found notable differences in the quantity of RNA recovered when using different extraction kits. In terms of quality, three of the kits performed better than the other four in terms of RQS and DV200 values. CONCLUSION: Though many laboratories have developed their own protocols for specific tissue types, using commercially available kits is still a popular option. Although these kits use similar processes and extraction procedures, the amount and quality of RNA obtained can vary greatly between kits. In this study, among the kits tested, while the Roche kit, provided a nearly systematic better-quality recovery than other kits, the ReliaPrep FFPE Total RNA miniprep from Promega yielded the best ratio of both quantity and quality on the tested tissue samples.

Paraffin Embedding↗

PubMed1978

Performance of the African giant rat (Cricetomys gambianus Waterhouse) on commercial rations and varying dietary protein levels.

The growth performance of 24 weanling giant rats was studied in 2 experiments of 30 weeks duration with commercial livestock rations and graded levels of protein. Daily average liveweight gain was 5.1-7.3 g, food consumption 26.9-36.3 g on 6 diets. Food intake, growth rate and food efficiency ratio were very similar using the different commercial diets. Growth performance improved as the dietary protein level was raised from 10 to 13%, but a further increase to 16% did not result in greater growth. The commercial pig ration and the experimental diet containing 13% dietary protein level were found to give satisfactory growth, and are recommended for studies with these animals.

Africa↗

PubMed1977

[Clinical effects of monocomponent insulin and commercial insulin preparations on insulin requiring diabetics (author's transl)].

Diurnal variation of blood sugar, C-peptide immunoreactivity (CPR), free insulin and total insulin were measured in 10 insulin requiring diabetics after obtaining adequate control of diabetes with commercial lente insulin treatment. Following these tests, insulin treatment were changed to monocomponent insulin (MC-insulin) from commercial lente insulin treatment in all subjects and the same tests were performed at 7th day of MC-insulin treatment. Diurnal variations of blood sugar in both groups were not changed significantly. Also changes in CPR of both groups were nearly same magnitude and endogenous insulin secretion in these insulin treated diabetics were suggested except a case of juvenile diabetic subject. However personal variation were great in diabetics with high antibody titer, diurnal variations of total extractable insulin in both groups were quite comparable. And mean diurnal changes in free insulin were resemble to that of CPR. All of these data suggested that clinical effects of MC-insulin and commercial insulin treatment on insulin requiring diabetics were comparable except insulin antibody or proinsulinspecific antibody production.

Adult↗

PubMed1979

Minimizing costs for casting gold alloy in student preclinical courses and commercial laboratory clinical use.

With inflation producing a consistantly rising price for casting gold alloy, student use in preclinical courses and clinic use in commercial laboratory castings represent a significant cost to the student and the school. The New Jersey Dental School has developed and instituted a plan to decrease student cost and manage commercial laboratory fees by the purchase of a year's supply of gold. Students use the gold alloy and pay only for lost amounts, while the school replaces the gold used by the commercial laboratory.

Dental Casting Investment↗

PubMed1978

In vitro evaluation of three commercial sustained-release papaverine hydrochloride products.

Three commercial sustained-release papaverine hydrochloride products in the form of microencapsulated pellets were evaluated. Three different dissolution apparatuses were used: a continuous flow apparatus, the USP rotating basket apparatus, and a modified reciprocating basket apparatus. The frequency rate of the reciprocating basket apparatus could be varied from 0 to 31 strokes/min. Salicylic acid compacts were used as a standard to characterize each apparatus. A linear log--log correlation between dissolution rate and apparatus speed or flow rate was obtained. Release of papaverine hydrochloride from the commercial preparations was affected significantly by the pH of the dissolution media but not by the agitation intensity.

Chemistry, Pharmaceutical↗

PubMed1979

High-performance liquid chromatographic separation and identification of epimeric 17-ketone impurities in commercial sample of dexamethasone sodium phosphate.

A commercial sample of dexamethasone sodium phosphate solution for injection was found to contain 56% of the label concentration and to be extensively contaminated (approximately 50%) with a white insoluble solid, which was identified as a mixture of the 16 alpha- and 16 beta-methyl epimers of 9-fluoro-11 beta-hydroxy-16-methylandrosta-1,4-diene-3,17-dione. High-performance liquid chromatography (HPLC) was used to separate, identify, and quantitate these epimers and to determine their presence in commercial samples. One epimer was identified by HPLC comparison with a synthesized specimen of 9-fluoro-11 beta-hydroxy-16 alpha-methylan-drosta-1,4-diene-3,17-dione. The second peak was identified as the 16 beta-epimer by epimerization of the synthesized alpha-component with alkali to obtain a product whose chromatogram matched that of the impurity. These conclusions are supported by data obtained by IR and UV spectrophotometry, TLC, and the blue tetrazolium test.

Chromatography, High Pressure Liquid↗

PubMed1979

Stability of amitriptyline hydrochloride in a commercial aqueous solution.

A commercial amitriptyline hydrochloride solution was stored at 80 degrees for up to 3 months. High-performance liquid chromatography showed no evidence of amitriptyline hydrochloride degradation. The method also indicated that two reported degradates, 3-(propa-1,3-dienyl)-1,2;4,5-dibenzocyclohepta-1,4-diene and dibenzosuberone, were present at levels less than 0.1% (the detection limit of the method) under the storage conditions. The stability of the commercial solutions is attributed to their relatively low ratio of headspace oxygen to amitriptyline hydrochloride.

Amitriptyline↗

PubMed1977

Comparison of cost of preparing reagents in laboratory with cost of using commercial kits.

A comparison of the cost of laboratory-made reagents with that of commercial kits was made for three serum-enzyme estimations and three serum-hormone estimations. The cost of reagents in kit form could only be justified on economic grounds for serum aspartate transaminase, alanine transaminase, and lactic dehydrogenase if the laboratory performed less than about 35 tests per day. It is unlikely that the use of kits for serum tri-iodothyronine, thyroxine, and thyrotrophic hormone can be justified on economic grounds for any workload. It is estimated that between 2 million pounds and 3 million pounds is spent unnecessarily by the National Health Service each year to purchase commercially prepared reagents for the six tests studied.

Alanine Transaminase↗

PubMed1978

Modulation of the formation of the amplification convertase of complement, C3b, Bb, by native and commercial heparin.

Native rat mast cell macromolecular heparin proteoglycan and commercial hog heparin glycosaminoglycan chains inhibit generation of the amplification convertase, C3b, Bb. The inhibitory action of heparin is not due to chelation of magnesium. Heparin is most active in inhibiting convertase formation on cellular intermediates formed with the lowest C3b input and developed with the highest B concentration, thereby suggesting the receptor site for B on C3b as the point of heparin action. This interpretation is consistent with the demonstration that heparin prevents B utilization during the fluid phase interaction of C3b, B, and D. Inhibition is observed also when C3b,Bb generation takes place on cellular intermediates in the presence of P or C3NeF, which yield stabilized forms of the convertase. 50 times the concentration of heparin required to inhibit convertase generation does not accelerate the decay of the unstabilized or the C3NeF-stabilized convertases and has only a modest effect on the P-stabilized convertase. An additional effect of heparin is to impair beta1H-mediated decay-dissociation of C3b,Bb. The concentration of native or commercial heparin which prevents convertase formation is in the same range as that required for the demonstration of its anti-coagulant and anti-thrombin III cofactor activities. The additional finding that this inhibitory action of heparin can be expressed by the isolated mast cell granule suggests that native heparin may contribute to the modulation of the amplification pathway of complement.

Animals↗

PubMed1977

Determination of factor VIII-related antigen using commercial antisera.

Commercially available antiserum to factor VIII was used in several tests to determine whether it might serve as a reference between research laboratories involved in investigation of the factor VIII complex and whether the antiserum might be useful in the screening of large populations of patients with hereditary disorders of factor VIII. In Ouchterlony plates, the antiserum gave a single line of identity with concentrated factor VIII, cryoprecipitate, and human plasma. The antiserum was capable of inhibiting the ristocetin response of normal platelets. Testing antigenic factor VIII by the Laurell technic with the commercial antiserum on plasmas from normal and stressed normal controls, patients with von Willebrand's disease, patients with hemophilia A, and obligate carriers of hemophilia A gave diagnostic and reproducible results.

Adult↗

PubMed1979

Mite allergen content in commercial extracts and in bed dust determined by radioallergosorbent tests.

Radioallergosorbent (RAST) direct binding and inhibition type assays were used to quantitate the mite (Dermatophagoides pteronyssinus) allergen content of four commercial mite extracts and a laboratory prepared extract from freeze-dried mites. The content of mite allergen in extracts prepared from twenty samples of dust vacuumed from bedding was measured by RAST inhibition assay. The four commercial mite extracts designated A, B, C and D, and the laboratory extract, designated L, contained 52, 265, 108, 1.5 and 581 arbitrary units of allergen/ml for the direct binding assay and 128, 111, 217, approximately 1 and 1083 arbitrary, but different, units of allergen/ml for the inhibition assay respectively. Qualitative differences between at least two extracts were suggested by the different slopes obtained when allergen binding of anti IgE was plotted against the volume of extract used in the direct binding assay. Differences in slope between the two extracts were also apparent when they were used in the inhibition assay. The quantities of mite allergen/gm of bed dust expressed in arbitrary units for the inhibition assay were 24 to 457 (mean 129) units. These quantities are similar to and sometimes greater than the quantity in 1 ml of mite extract and so confirm bed dust as a potent source of mite allergen. There was no significant correlation between the weight of dust, the numbers of dead and live mites and the allergen content of dust.

Allergens↗

PubMed1977

Distribution of IgG subclasses in commercial and some experimental gamma-globulin preparations.

The IgG subclass distribution was determined in six commercial and in four experimental human gamma-globulin preparations. The concentrations of IgG subclasses were measured in a modified radiommunoassay using subclass-specific antisera. In commercial gamma-globulins, the distribution of the subclasses corresponded roughly to the distribution in normal human serum. A considerable enrichment of the IgG 4 was found in experimental lots prepared either from the ethanol fraction III or from the rivanol-precipitable IgG.

Blood Specimen Collection↗