The effect of sterilization on transforming growth factor beta isolated from demineralized human bone

Growth factors have been identified as the primary cause of osteoinduction in bone healing. Transforming growth factor beta (TGF- beta) has been shown to promote bone formation and is present in bone in high quantities. The aims of the present study were to isolate TGF- beta from human bone, demonstrate its biologic activity, and analyze the effects of conventional sterilization techniques on activity. Bone, obtained from femoral heads of five patients (mean age, 70 years) was ground, demineralized, and freeze-dried, and samples from each patient were divided into three groups: no treatment, sterilization with 1.60 to 1.94 Mrad of 60Co irradiation, and sterilization with ethylene oxide (ETO). Carrier-free recombinant TGF-beta control was also treated and was totally inactivated by ETO but not by irradiation (p < 0.01). TGF- beta activity in demineralized bone was not significantly diminished (p > 0.1) by either sterilization procedure, and substantial amounts of active TGF-beta were recovered in all bone samples: 1.04 +/− 0.77 ng per mg of protein in irradiated samples, 0.67 +/− 0.26 ng per mg in ETO- treated samples, and 1.04 +/− 0.33 in untreated samples, respectively (mean +/− SD). Although a recent report demonstrated that the osteoinductive activity of bone morphogenetic protein in bone powder is diminished considerably by ETO and by 2.5 Mrad of irradiation sterilization of bone powder, these data demonstrate that TGF-beta activity, with its osteoinductive properties, was not destroyed in more coarsely ground, demineralized bone by ETO or by lower doses of irradiation. These findings support the use of human bone allografts in clinical instances involving impaired bone formation.     

LONG-TERM POTASSIUM SUPPLEMENTATION LOWERS BLOOD PRESSURE IN ELDERLY HYPERTENSIVE SUBJECTS

Following a randomised cross-over trial of the effect of a four-week 60 mmol/day potassium supplement versus placebo on blood pressure (BP), eight of the original 18 hypertensive subjects continued with a 48 mmol daily potassium supplement for four months. For these eight subjects 24-h potassium excretion during placebo, one month of 60 mmol and four months of 48 mmol daily potassium supplementation phases was 56 ± 23, 102 ± 28 and 90 ± 35 mmol/24 hours, respectively, and mean 24-h BP following each phase was 160 ± 16/89 + 11, 147 ± 13/83 ± 12 and 145 ± 14/81 ± 9 mmHg respectively, a significant fall in mean 24-h SBP between four months of potassium supplement and placebo period of 15 ± 13 mmHg (95% CI: 4, 26 mmHg, p=0.02), although the fall in 24-h DBP was not significant (8 ± 11 mmHg, 95% CI: 0, 17 mmHg, p=0.08). Modest increases in dietary potassium intake could have significant effects on lowering BP in the large proportion of elderly subjects with hypertension.     

Analysis of T-cell receptor beta chain (T beta) gene rearrangements demonstrates the monoclonal nature of T-cell chronic lymphoproliferative disorders

We investigated the rearrangement patterns of the gene coding for the beta chain of the T cell receptor (T beta) in 11 patients with T-cell derived chronic lymphoproliferative disorders, including T-cell prolymphocytic leukemia (T-PLL) and T-cell chronic lymphocytic leukemia (T-CLL). We found that all five cases of T-PLL, and five of six cases of T-CLL, displayed T beta-gene rearrangements, clearly establishing their monoclonal nature. Clonality could not be determined in one case of T-CLL where the T beta gene was found unrearranged. Our results demonstrate that the majority of cases of both clinically aggressive T- PLL and clinically indolent T-CLL are monoclonal. These results suggest that the analysis of T beta gene rearrangements represents a valid tool for the differential diagnosis and clinical monitoring of T-cell derived chronic lymphoproliferative diseases.     

Erectile Impotence in Chronic Alcoholics

Erectile impotence is a common complaint in alcoholics, but its mechanism is unknown. We have studied nocturnal penile erection in 13 alcoholics who complained of impotence. Seven had normal erections and their impotence was therefore psychogenic. Six were found to have diminished or absent nocturnal erections. Plasma concentrations of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were elevated in this latter group, with the exception of one patient who had only raised FSH. They also had more evidence of neurological damage than the other seven alcoholics, and two had evidence of damage to the parasympathetic nervous system. Investigation of erection during sleep in alcoholic patients with impotence may be useful in differentiating clinically between patients with psychogenic causes and patients with organic causes of impotence.     

Propulsion and retropulsion of normal colonic contents

Conclusion In conclusion, it may be said that the propulsion of colonic contents can be effected either by systolic or progressive contractions of the bowel wall. The two modes of transportation can usually be identified in time-lapse cinefluorograms even at 1 frame/min from the regularity of the movement of opaque contents. Evidence is presented of a form of progressive propulsion which has all the characteristics of peristalsis that are recognizable by this method of study, and yet is capable of travelling adorally up the colon. It is not possible to say what the relationship of this kind of movement is to the strictly aboral mass peristalsis with which workers in this field are so much more familiar.Supported by grants from the Medical Research Council and the Nuffield Committee.     

High-level expression and purification of a recombinant human erythropoietin produced using a baculovirus vector

Conditions presently have been established for the high-level expression and simplified purification of recombinant human erythropoietin produced in Spodoptera frugiperda cells. Expression, as mediated by infection with a recombinant baculovirus, was accomplished in suspension culture using reduced levels of serum and media supplements experimentally determined to provide optimum levels of factor production (500,000 U/L). Purification of this recombinant human erythropoietin to virtual homogeneity (greater than or equal to 99%) was accomplished via a simple three-step procedure involving isocratic elution from DEAE-Sephacel, reverse-phase high performance liquid chromatography (HPLC) on a C4 medium, and the single-step elution of purified hormone from concanavalin A agarose. Overall, an 890-fold purification was accomplished with a recovery of 80% as assayed in vitro. Biologically, this purified erythropoietin is highly active, possessing a specific activity in vitro of 200,000 U/mg protein. Chemically, this erythropoietin (molecular weight [mol wt] 26,200) appears exceptionally uniform in its oligosaccharide constitution (30%) as contrasted with heterogeneously glycosylated erythropoietins derived from mammalian cells (mol wt 30,000 to 38,000; 40% to 50% complex-type oligosaccharide). Thus, human erythropoietin as presently produced in an insect cell line comprises not only an abundant source of highly active, readily purified hormone for studies of its mechanism of action and cell surface receptor, but also represents a uniquely homogeneous form that should prove advantageous for direct structural analyses.