Hypersensitivity reactions to streptokinase in patients with high pre-treatment antistreptokinase antibody and neutralisation titres.

After streptokinase or antistreplase administration, raised antibody levels can persist for many years, but it is unclear if these antibodies can cause allergic reactions following streptokinase re-administration for myocardial re-infarction. Pretreatment antistreptokinase antibody (AB) and neutralisation titres (NT) were measured in 189 consecutive patients (57 received streptokinase or anistreplase). Seven patients had previous exposure to streptokinase or anistreplase; they had high mean (SEM) antibody titres of 1:801 (332) and neutralisation titres of 3.

An interview study of participants in the Tacoma, Washington, syringe exchange.

Although European and Australian studies of syringe exchange programs have reported safer injection among participants and no increase in drug use, the generalizability of these findings to the US is uncertain. We report on the operations and potential effectiveness of the longest-operating syringe exchange in the US and compare our results to studies of exchange programs outside the US. The sample of 204 study subjects reported no change in the frequency of injection, from 155 to 152 injections per month, and a decline in the frequency of unsafe injections, from 56 to 30 times per month, while participating in the program.

A quantitative thrombin time for determining levels of hirudin and Hirulog.

The anticoagulant effect of recombinant hirudin (rHir) and Hirulog has been monitored in patients with the activated partial thromboplastin time. Accurate monitoring with this test cannot be achieved if plasmas contain heparin, lupus anticoagulants, low concentrations of fibrinogen or other factors, or elevated fibrinogen-fibrin degradation products (FDP). We have therefore developed a simple, rapid, sensitive clot-based method, the quantitative thrombin time (QTT), to measure levels of rHir and Hirulog in patient plasma (or whole blood).

Effect of DNA-repair enzymes on mutagenesis by oxygen free radicals.

Cytosine to thymine transitions are among the most common types of mutations produced by oxygen damage to DNA. One possible mechanism for these transitions is deamination of cytosine to uracil. Using both a forward mutation assay as well as a reversion assay specific for damage to cytosines we show that direct deamination to uracil does not play a significant role in mutagenesis induced by reactive oxygen free radicals.

Nickel induces a signature mutation for oxygen free radical damage.

We have determined the specificity of mutations produced by nickel(II), a known human carcinogen, in a forward mutation assay and also used a sensitive reversion assay to show that Ni(II), like iron and copper, can produce tandem double CC-->TT mutations, a hallmark of damage to DNA by either UV irradiation or oxygen free radicals. A reduction in mutation frequencies by the addition of oxygen radical scavengers also supports the involvement of reactive oxygen species in DNA damage and mutagenesis by Ni(II). Mutagenesis by Ni(II) is enhanced by the addition of both hydrogen peroxide and a tripeptide glycyl-glycyl-L-histidine.

Structure of a 2-arylquinoline dimer, a compound with a new ring system.

The title compound, 6,15-dimethyltribenzo-[c,f,j]naphtho[1,2,3,4-lmn][2,7]phe nanthroline was obtained in low yield from the reaction of 2-(4-methylphenyl)quinoline and various aryllithiums. The compound is a 'dimer' in which two phenylquinoline units are joined by three bonds; the dimer has exact twofold symmetry. Non-bonded interactions produce substantial out-of-plane distortions.

Aztreonam selective agar for gram positive bacteria.

Aztreonam blood agar, a new selective medium for Gram positive aerobic bacteria, was evaluated in comparison with conventional media for skin swabs. Aztreonam agar increased the number of isolates of Staphylococcus aureus by 17%. By producing purer growths on primary isolation, it significantly speeded up the identification and sensitivity testing of staphylococci and streptococci.

Stimulation of epithelial cell growth by the neuropeptide substance P.

The neuropeptide substance P (SP) was found to stimulate DNA synthesis and cell growth for epithelial cells (cornea and lens) in a serum-free environment. The length of treatment time was shown to be important since longer times shifted the dose-response curve to the left. In short-term DNA synthesis studies (40 h) the stimulation with SP (or synergism with insulin) was not apparent until close to 10 microM, however, when DNA synthesis assays were carried out over a long period of time (5 days) stimulation with SP was seen at 1 pM.

Tandem double CC-->TT mutations are produced by reactive oxygen species.

Oxidative damage to DNA is mutagenic and thus may play a role in carcinogenesis. Because of the large number of different DNA lesions formed by oxidative species, no genetic alteration so far identified is exclusively associated with oxygen damage. Tandem double CC-->TT mutations are known to occur via UV damage to DNA and are thought to be a specific indicator of UV exposure.

Defensins are mitogenic for epithelial cells and fibroblasts.

Defensins are a family of structurally homologous peptides contained within phagocytic cells. Although these peptides are best known for their broad spectrum antimicrobial properties, they also inhibit ACTH (corticotropin) stimulated corticosterone production, chemoattract monocytes, and lyse mammalian cells. We now report that these peptides are potent mitogens in vitro in the same concentration range that they display potent antimicrobial activity in vitro.

Familial cold urticaria. Investigation of a family and response to stanozolol.

Background: Familial cold urticaria is a rare cutaneous and systemic reaction to cold with autosomal dominant inheritance, distinctive clinical features, and unknown pathogenesis. Release of a chymotrypsinlike substance has been postulated. To date, no effective treatment has been reported.

Raised levels of antistreptokinase antibody and neutralization titres from 4 days to 54 months after administration of streptokinase or anistreplase.

Streptokinase and anistreplase are antigenic and their administration often leads to antibody formation. These can cause allergic reactions and/or neutralization of streptokinase with resulting suboptimal treatment. Currently, streptokinase re-administration is considered appropriate for up to 5 days and from 1 year after a previous dose.

Impact of omeprazole on the plasma clearance of methotrexate.

Omeprazole inhibits the gastric hydrogen pump and is an effective treatment for peptic ulcers. Methotrexate is a chemotherapeutic agent that inhibits dihydrofolate reductase and is eliminated by a hydrogen-ion-dependent mechanism in the kidney. We present evidence that omeprazole inhibits methotrexate clearance and may result in potentially toxic methotrexate levels.

Iron malabsorption in a patient with large cell lymphoma involving the duodenum.

Iron malabsorption compounded the anemia in a patient with diffuse large cell lymphoma involving the small intestine. Both upper gastrointestinal series with small bowel follow-through and computerized tomographic scan demonstrated lymphomatous involvement of the duodenum and proximal jejunum by a retroperitoneal mass. An oral iron-loading absorption test was consistent with malabsorption of iron.

Corneal storage medium preservation with defensins.

We used a synthetic defensin (rabbit neutrophil peptide-1; NP-1) as a microbicide in a corneal storage medium, Optisol without antimicrobial compounds. We established growth curves in Optisol for Staphylococcus aureus, Streptococcus pneumoniae, and Pseudomonas aeruginosa. Each organism was evaluated separately at 4 degrees C, 23 degrees C, and 37 degrees C in Optisol with NP-1 at each of four different concentrations including 1, 10, 100, and 200 micrograms/ml.