Glycosylated haemoglobin and plasma glycoprotein assays by affinity chromatography

Summary A rapid chromatography method for separating glycosylated protein from non-glycosylated protein, using a boronate-agarose affinity medium which selectively binds the cis-diol groups of glycoproteins, was used to quantitate plasma glycoprotein as well as glycohaemoglobin. The results were found to be independent of: (1) temperature from 16.5 to 29.8 °C; (2) haemoglobin variants, and (3) aldimine glycoprotein adducts. Thus several of the common problems occurring in existing haemoglobin a₁ assays are eliminated. There was a close correlation between glycohaemoglobin measured by affinity chromatography and haemoglobin A₁ by cation-exchange (r = 0.959, n = 215). Specimens from 103 diabetic patients and 112 healthy volunteers were assayed. The following reference ranges were established: glycohaemoglobin 5.5–8.4%; glycosylated total protein 11.5–16.2%; glycoalbumin 11.6–19.5%.     

Malignant transformatin of human bronchial epithelial cells by radon-simulated {alpha}-particles

Epidemiological studies have shown that inhalation of radonis associated with an increased risk for bronchogenic carcinomain uranium miners. These     

Hypoglycemic events and glycosylated hemoglobin values in patients with type 2 diabetes mellitus newly initiated on insulin glargine or premixed insulin combination products.

PURPOSE: Rates of hypoglycemic events and their associated costs were compared among patients with type 2 diabetes mellitus newly initiated on insulin glargine or a premixed insulin fixed-combination product. METHODS: Patients newly initiated on insulin glargine or premixed insulin fixed-combination products (including pen delivery systems) between June 1, 2001, and February 29, 2004, were identified using an administrative claims database. Hypoglycemic events were identified from International Classification of Diseases, 9th Revision, Clinical Modification codes. Multivariate analyses were performed. RESULTS: A total of 2315 patients met the inclusion criteria. Of those, 1212 received insulin glargine and 1103 received a premixed fixed-combination insulin product. The mean +/- S.D. treatment duration was 13.7 +/- 8.1 months. Patients treated with premixed insulin had a higher hypoglycemic event rate than glargine patients (13.8 versus 7.0/100 patients/year; p = 0.027), which yielded a number needed to treat of 15 patients. The mean cost per hypoglycemic event was $1049 (95% confidence interval, $426-1672). The mean annual cost of all insulin use was $46 more for the insulin glargine cohort than for those who received premixed insulin ($534 versus $488, respectively) (p < 0.05). Mean postindex insulin use was higher in patients receiving premixed insulin than in those treated with insulin glargine (48.1 versus 43.8 units per day) (p < 0.05). CONCLUSION: Patients with type 2 diabetes mellitus who were newly initiated on insulin glargine had a lower rate of hypoglycemic events compared with patients newly initiated on a premixed fixed-combination insulin product. Treatment of 15 patients with insulin glargine instead of premixed insulin for one year would avoid one hypoglycemic event per year.     

Cytogenetic and molecular genetic analysis of tumorigenic human bronchial epithelial cells induced by radon alpha particles

To establish a cell culture model for lung carcinogenesis, independent populations of the human papillomavirus 18-immortalized human bronchial epithelial cell line BEP2D were treated with high linear energy transfer radon-simulated alpha-particles, expanded and xenotransplanted into Nu/Nu mice. Six independent cell lines were established from tumors that developed from three separate radiation treatments as follows: treatment (Tx) 1 (30 cGy--two doses), H2BT, Tx 2 (30 cGy-- single dose), R30T1L, R30T2 and R30T3L, Tx 3 (30 cGy--single dose), H1ATN and H1ATBA1. Cytogenetic analysis revealed common changes in all tumor lines: loss of the Y chromosome (ch), one of three copies of ch8, one of three copies of ch14, and one of two copies of ch4p16-pter and ch11p15-pter. Analysis of polymerase chain reaction-amplified short tandem repeats of informative loci confirmed the loss of chY in all lines and loss of heterozygosity (LOH) at eight loci spanning the length of ch8 in all lines from Tx's 1 and 2. Our data support previous studies indicating the presence of tumor suppressor genes on ch8. LOH also was confirmed on ch14 at locus D14S306 in all cell lines from Tx 2 and in one of two lines from Tx 3. This region, 14q12-q13, may contain changes in one of the five known somatostatin receptor genes (SSTR1). No LOH was detected at any of the informative loci tested for on ch4 or ch11.      

Simple and complex antibody reactions in radioimmunoassay and the prediction of assay characteristics

Radioimmunoassays are usually developed empirically since there have been few established rules which cover general RIA behaviour. Evidence is presented which enables the delineation of 2 types of RIA with distinct group characteristics. (1) Simple RIA, conforming to the law of mass-action kinetics, is a result of univalent interaction. Examples of simple RIA include hapten assays and those using a monoclonal antibody (McAb). (2) Complex RIA occurs when antigen reacts multivalently with a polyclonal antiserum (PcAs). The formation of multicomponent complexes between a large molecular weight antigen and a PcAs is demonstrated using gel exclusion chromatography. These complexes are resistant to dissociation and are responsible for higher affinity, greater sensitivity and slower equilibration times compared to simple RIA. The assignment of an assay to either the simple or complex RIA group is dependent upon either the molecular size of the antigen or the use of a McAb. The consequent predictability of RIA behaviour enables a more rational approach to optimal assay design than current theory allows. It is advocated that the inability of a McAb to form multicomponent complexes is a major disincentive to their indiscriminate adoption in RIA.     

Central muscle relaxant properties of 2,6-dimethylphenethylurea and related compounds

Twenty-eight phenylalkylureas with alkyl, hydroxy, methoxy or chloro-substituents in the aryl ring have been synthesized and tested for central depressant and muscle relaxant properties. In this series, the dimethylphenethylureas with at least one ortho-methyl group show unexpectedly selective muscle relaxant activity. 2,6-Dimethylphenethylurea inhibits polysynaptic reflexes more readily than monosynaptic ones, but also depresses muscle contractions by an action independent of its effect on interneuronal transmission. It is a weak anticonvulsant, suppresses rage episodes in “fighting” mice, and has no selective blocking action on conditioned responses. It thus has a pharmacological profile resembling those of mephenesin and meprobamate, but distinct from either, and differing still more from those of phenobarbitone, chlordiazepoxide or chlorpromazine. However, tolerance to its action develops readily.     

Further studies of rimiterol and salbutamol administered by intermittent positive-pressure ventilation, and an important observation on the technique of using the Bennett ventilator.

1. Using the same technique of administering drugs by intermittent positive-pressure ventilation as used in previous studies a source of contamination of solutions nebulized was discovered. This was rectified by using a new ventilator and completely separate patient circuits for each solution nebulized. 2 Salbutamol 0.5% and 0.25% solutions achieved the same degree of bronchodilatation, but there was a significantly greater increase in heart rate produced by salbutamol 0.5%. 3 Rimiterol 0.5% and salbutamol 0.25% produced similar peak mean improvements in FEV and also induced the same degree of tachycardia, but the duration of these effects were significantly shorter in the case of rimiterol. 4 The sustained degree of bronchodilatation achieved by salbutamol 0.25% could not be mirrored by giving two doses of rimiterol 0.5%, the second dose 2 h after the first. 5 Rimiterol 0.5% induced a degree of tachycardia which was similar in peak effect to that observed after salbutamol 0.25%. However, in the controls the second dose of rimiterol, given 2 h after the first, was responsible for only a small increase in heart rate which was not significantly different than that after saline in the other three treatment groups.