Nucleosome-associated protein kinases in murine erythroleukemia cells.

Chromatin subunits from murine erythroleukemia cells were prepared by a method which releases actively transcribing genes. Two casein kinase activities (CK₁ and CK₂) were isolated from these nucleosomes by gel nitration in 0.5 m NaCl. CK₁ (M_r ~ 200,000) and CK₂ (M_r ~ 35,000) were further purified by phosphocellulose chromatography and characterized with regard to several parameters which may regulate their activity in vivo. CK₁ has an NaCl optimum of 0.14 m, utilizes GTP as phosphate donor ~25% as efficiently as ATP, and phosphorylates a discrete group of high molecular weight nonhistone proteins in the unfractionated chromatin starting material. CK₂ has an NaCl optimum of 0.24 m, cannot utilize GTP, and modifies a different group of nonhistones. Both kinases are inhibited by concentrations of hemin (<50 μm) which efficiently induce globin gene expression in erythroleukemia cells. A histone kinase resolved during the gel filtration step is unaffected by hemin. An investigation of the mode of hemin inhibition reveals that CK₁ and CK₂ interact in different fashions with the inhibitor.     

Single channel gating events in tracer flux experiments I. Theory

Tracer ion flux measurements are a commonly used method for studying ion transport through membranes of cellular systems, where the rate of ion flow is determined by gating processes which control the opening and closing of transmembrane channels. Due to recent advances in the theoretical analysis of tracer flux from or into closed membrane structures (CMS), the mechanism of gating reactions can, in principle, be derived from flux data. A physically well founded analysis is presented for the dependence of the total tracer ion content of a collection of CMS on the gating processes. For functionally uncoupled gating units a mean single channel flux contribution [equation, see text] can be defined, where k is the intrinsic single channel flux coefficient, t the time over which flux is measured, and p(tau,t) is the probability that a given channel was open for a total period tau during t. This quantity reflects the mean time course of the tracer content due to flux through a single channel. Expressions for are derived that explicitly take into account a distribution in the lifetime of open channels. On the basis of the results, kinetic and thermodynamic parameters of multiphasic gating reactions can be determined from the time course of the overall tracer content in a colleciion of CMS.     

Comparison between penicillamine and sulphasalazine in rheumatoid arthritis: Leeds-Birmingham trial.

Sulphasalazine was first formulated by Svartz in the early 1940s, specifically for use as a remission inducing drug in rheumatoid arthritis. After the publication of an unfavourable trial, however, the drug was restricted to patients with ulcerative colitis. In the late 1970s sulphasalazine was re-examined in rheumatoid arthritis and favourable results reported in "open" trials. A double blind controlled trial was therefore conducted comparing enteric coated sulphasalazine and D-penicillamine in patients with active rheumatoid arthritis. A total of 63 patients were recruited in two centres; 31 were treated with sulphasalazine and 32 received penicillamine. After 16 weeks'' treatment both drugs had produced significant improvements in clinical score, pain score measured on a visual analogue scale, grip strength, Ritchie articular index, erythrocyte sedimentation rate, and serum C reactive protein concentration. Nausea was the major side effect in the sulphasalazine treated group. No potentially dangerous effects of sulphasalazine were encountered in contrast with those seen in the penicillamine group. The results suggest that sulphasalazine is an effective and safe drug capable of producing remissions in active rheumatoid arthritis. They also lend confidence to the use of preliminary "open" trials as a means of screening for remission inducing drugs in rheumatoid arthritis.     

Cryosurgery of lentigo maligna.

Lentigo maligna denotes flat, pigmented lesions predominantly in areas of actinic damage that have the propensity to become malignant. More than 10 years may pass before lentigo maligna evolves into an invasive neoplasma. As an invasive process, it is termed lentigo maligna melanoma (LMM), and it has the potential for both lymphatic and hematogenic metastases. Because of the size and location of the lesions, cosmetically unsatisfactory scars may result from conventional surgery. Therefore, alternative means of treatment, including cryosurgery, have been employed. We report on 12 patients suffering from lentigo maligna who had been treated successfully by cryosurgery between 1984 and 1990. The average follow-up period was 51.4 months, and the recurrence rate was 8.3 percent. Knowing that microinvasive components can be demonstrated in 15 percent of lentigo maligna lesions, we retrospectively reassessed our patients by immunohistochemical procedures with S-100 protein. Although intradermal microinvasion could be confirmed in one patient, no recurrence had been observed within 61 months of follow-up. Provided that patients are selected properly and extension of cryonecrosis is monitored, cryosurgery may prove an efficient alternative to conventional surgery in the treatment of lentigo maligna.     

Effects of energy level and monensin on reproductive performance and lactation of beef cows

This experiment consisted of a 2 year drylot study involving 80 multiparous, suckled beef cows (40 Angus and 40 Herefords). Experimental treatments (breed, monensin and year) were arranged in 2(3) factorial to evaluate the effect of breed and monensin on reproductive performance and lactation. Cows received 85% of the NRC total digestible nutrient (TDN) requirement for the first 56 days of the 140 day trial. Cows were synchronized with Synchro-Mate B and artificially inseminated 30 days into each trial with blood samples collected for luteinizing hormone (LH) analysis from one-half of each treatment group from 24 to 36 hours after implant removal. Progesterone determinations were made on plasma samples collected at day 9 and 16 after implant removal. On day 56, milk yield estimates were obtained by the weigh-suckle-weight technique. Following these collections, energy levels were increased by allowing ad lib consumption of forage. Calves, which were removed from the cows during feeding, were given access to a 75% TDN creep ration after day 56. Milk estimates were again evaluated at 140 days. Monensin supplementation did not result in a difference in cow weight change through the restricted energy period (first 56 days) or throughout the entire 140 day period. Milk yield estimates at 56 and 140 days and calf gains throught the trial, were unaffected by monensin supplementation. Monensin resulted in no effect on conception rate or services per conception. The time of the LH peak was shifted slightly forward by monensin although not significantly. Progesterone levels were not consistently affected by monensin supplementation.     

A haemagglutination inhibition test kit for routine analysis of erythropoietin.

A commercially available haemagglutination inhibition test kit for routine analysis of erythropoietin was shown to be unable to detect elevated levels of serum Epo.     

Correlations between human portal and peripheral venous insulin and proinsulin concentrations under glucose infusion]

In 8 female patients carbohydrate tolerance was proved by means of glucose infusion test 3 days after cholecystectomy. Parameters analyzed in portal and peripheral vein blood are compared with that of 47 healthy persons. All patients demonstrate a pathological carbohydrate tolerance after cholecystectomy, further characterized by an increased lipolysis, a paradoxical rise of HGH, a diminished insulin secretion during the early and increased IRI output in the second phase. There is a significant positive correlation between portal and peripheral vein IRI concentration despite the rising portalperipheral venous IRI difference with raised portal venous IRI concentration. Corresponding differences for proinsulin concentrations can be established in the early phase only. Relations existing between blood glucose and IRI are shown by multiple regression analysis. They suggest that the altitude of IRI concentration is determined by previous blood glucose concentration.     

Results of long-term biguanide therapy as a preventive measure in protodiabetes]

55 patients with pathological glucose tolerance received a long term treatment with buformin (200 mg daily). In 43 of the protodiabetics the duration of treatment was one year, in 29 of them two years and in 11 three years. The age of the patients was 38 years and the mean relative body weight was 118 per cent. The effect of buformin on glucose tolerance and insulin secretion was tested with the glucose infusion test before and after the periods of treatment. After one year we found in 58 per cent, after two years in 69 per cent and after three years in 64 per cent of the protodiabetics an improvement of glucose tolerance. In these groups the results showed a rise of the IRI in the low responder and a decrease of the IRI in the high responder. The good effects on glucose tolerance were not demonstrable in the compared groups with long-term treatment of diet only.