Similarity of the structure of ferritin and iron . dextran (imferon) determined by extended X-ray absorption fine structure analysis.

Ferritin, a natural complex of iron oxide encased in protein, and iron . dextran, a synthetic complex of iron oxide coated with dextran, have the similar properties of maintaining high concentrations of iron in solution at physiological pH and releasing iron relatively slowly in vivo. Extended x-ray absorption fine structure (EX-AFS) analysis was performed on each complex and compared to see if the structures of the iron cores were similar. The results obtained from the extended x-ray absorption fine structure technique show that the near-neighbor environment around the average iron atom in ferritin and iron . dextran is identical, within experimental uncertainty, for the first three shells. The similarity of the iron cores in both complexes may explain the similarity of iron release in vivo. Ferritin has a protein coat which is composed of 24 subunits arranged in a hollow sphere with six channels through which the iron may move during deposition and release. However, little is known about the requirements of the protein structure in ferritin for the maintenance of high concentrations of iron in a soluble, nontoxic form or about the role of the protein in the release of iron from ferritin. The results suggest that iron . dextran will be a useful model compound in studies of the relation of the iron core and protein in ferritin to function.     

The evaluation of recombinant hookworm antigens as vaccines in hamsters (Mesocricetus auratus) challenged with human hookworm, Necator americanus

We have previously reported the successful adaptation of human hookworm Necator americanus in the golden hamster, Mesocricetus auratus. This animal model was used to test a battery of hookworm (N. americanus and Ancylostoma caninum) recombinant antigens as potential vaccine antigens. Hamsters immunized a leading vaccine candidate N. americanus-Ancylostoma secreted protein 2 (Na-ASP-2) and challenged with N. americanus infective larvae (L3), resulted in 30-46.2% worm reduction over the course of three vaccine trials, relative to adjuvant controls. In addition, significant reduction of worm burdens was also observed in the hamsters immunized with adult hookworm antigens A. caninum aspartic protease 1 (Ac-APR-1); A. caninum-glutathione-S transferase 1 (Ac-GST-1) and Necator cysteine proteases 2 (Na-CP-2) (44.4%, 50.6%, and 29.3%, respectively). Our data on the worm burden reductions afforded by these hookworm antigens approximate the level of protection reported previously from dogs challenged with A. caninum L3, and provide additional evidence to support these hookworm antigens as vaccine candidates for human hookworm infection. The hamster model of N. americanus provides useful information for the selection of antigens to be tested in downstream vaccine development.     

Role of whole-cell pertussis vaccine in severe local reactions to the preschool (fifth) dose of diphtheria-pertussis-tetanus vaccine.

OBJECTIVE: To estimate the contribution of whole-cell pertussis vaccine to severe local reactions after the preschool (fifth) dose of adsorbed diphtheria toxoid-pertussis vaccine-tetanus toxoid (DPT) vaccine. DESIGN: Double-blind randomized controlled trial. SETTING: Urban community. PARTICIPANTS: Volunteer sample of 200 healthy children 4 to 6 years old who were eligible for the fifth dose of DPT vaccine. INTERVENTIONS: Children received, in both arms, either diphtheria toxoid-tetanus toxoid (DT) and monovalent pertussis vaccines (group A, 99 children) or DPT and meningococcal vaccines (group B, 101 children). All were licensed products from single lots. The children were assessed 24 hours later by a trained observer. Serum samples obtained before vaccination were tested for antibodies to tetanus and diphtheria toxins and five pertussis antigens by means of enzyme-linked immunosorbent assay. MAIN OUTCOME MEASURES: Rates of severe local reactions (an area of redness or swelling or both of 50 mm or greater) 24 hours after vaccination. Relation between serum antibody levels before vaccination and rates of severe local reactions to corresponding vaccines. RESULTS: All of the subjects were followed up 24 hours after vaccination. Severe redness was present in 38% given DPT vaccine, 29% given intramuscular pertussis vaccine and 9% given DT vaccine (p < or = 0.002, three-way comparison). Severe swelling was common after vaccination with all three products. After intramuscular pertussis vaccination a relation was evident between the prevaccination levels of antibody to whole-cell pertussis bacteria and the rates of redness (p < 0.02) but not between the prevaccination subcellular antibody levels and the rates of redness. CONCLUSION: That pertussis vaccine resembled the DPT vaccine in causing severe redness suggests that it is the principal cause of such reactions after DPT vaccination. The DT vaccine was also reactogenic; thus, cumulative sensitization to one or more of its constituents may be a factor.     

Apparent diffusion limitations on branchial CO2 transfer are revealed by severe experimental anaemia in brown bullhead (Ameiurus nebulosus)

In this study, the rapid (within 2 h) effects of acute anaemia on blood gas and acid-base status, as well as cardiorespiratory variables, were examined in brown bullhead (Ameiurus nebulosus). Anaemia was induced by blood withdrawal coupled to volume replacement with saline. Lowering haematocrit from the control value of 23.5+/-1.0% (mean+/-S.E.M.; N=37) to 5.9+/-0.3% (N=37) resulted in a significant increase (by 2.63+/-0.51 torr; N=7) in arterial CO(2) tension (PaCO(2)) over the subsequent 2-h period in the absence of a change in arterial O(2) tension (PaO(2)). Treatment with bovine carbonic anhydrase (CA) reduced the extent of the PaCO(2) increase to the point where it was not statistically significant. In both control and CA-treated fish, arterial pH decreased during acute anaemia; the acidosis was of mixed respiratory and metabolic origin in control fish and primarily metabolic in CA-treated fish. Inducing anaemia caused increases in both cardiac output (V*b) and heart rate that were similar in control and CA-treated fish. Experimental elevation of V*b equivalent to that observed during anaemia, but in the absence of lowered haematocrit, increased PaCO(2) significantly by 1.49+/-0.74 to 1.64+/-0.78 torr (N=5) without affecting PaO(2). These findings suggest that CO(2) excretion in bullhead, as in rainbow trout, is effectively diffusion-limited, and that approximately half of the increase in PaCO(2) measured during the initial 2 h of anaemia results from the impact of increased blood flow (hence decreased gill transit time) in a diffusion-limited system.     

Bilirubin-Cu(II) complex degrades DNA.

It has recently been reported that bilirubin forms a complex with Cu(II). In this paper we show that the formation of the complex results in the reduction of Cu(II) to Cu(I) and the redox cycling of the metal gives rise to the formation of reactive oxygen species, particularly hydroxyl radical. The bilirubin-Cu(II) complex causes strand breakage in calf thymus DNA and supercoiled plasmid DNA. Cu(I) was shown to be an essential intermediate in the DNA cleavage reaction by using the Cu(I) specific sequestering reagent neocuproine. Bilirubin-Cu(II) produced hydroxyl radical and the involvement of active oxygen species was established by the inhibition of DNA breakage by various oxygen radical quenchers.     

Cost benefits of low dose subcutaneous erythropoietin in patients with anaemia of end stage renal disease.

OBJECTIVE--To assess the cost benefits of low dose subcutaneous recombinant human erythropoietin in correcting the anaemia of end stage renal disease. DESIGN--Three year retrospective study. SETTING--Subregional nephrology service serving a mixed urban and rural population of 800,000. SUBJECTS--60 patients with symptoms of anaemic end stage renal disease treated with erythropoietin (43 receiving haemodialysis; 11 receiving continuous ambulatory peritoneal dialysis; two with predialysis end stage renal disease; four with failing renal transplants). MAIN OUTCOME MEASURES--Costs and savings of achieving and maintaining a haemoglobin concentration of 85-105 g/l with erythropoietin. RESULTS--All patients treated with erythropoietin achieved the target haemoglobin concentration at median induction doses of 97 (95% confidence interval 95 to 108) units/kg/week, and this was maintained with 79 (75 to 95) units/kg/week at an average annual cost per patient of 2260 pounds. Admissions related to anaemia were virtually eliminated (246 v 1 inpatient days for 12 months before and after starting erythropoietin). 54 patients required no blood transfusions after starting erythropoietin, and the total requirements fell from 230 to 21 units in the 12 months before and after starting erythropoietin. Iron stores were maintained with oral or intravenous iron. All patients reported increased wellbeing, appetite, and exercise capacity. Hypertension developed or worsened in 30 patients, resulting in hospital admissions in five patients, one of whom had seizures. CONCLUSION--Low dose subcutaneous erythropoietin restores haemoglobin concentrations sufficiently to abolish blood transfusion requirements and reduce morbidity. The net cost of erythropoietin prescribed in this way (2260 pounds/patient/year) was largely offset by savings in costs of hospital admissions. The true annual cost to the NHS was around 1200 pounds per patient.     

Cytogenetical and clinical investigations in aplastic anaemia (Fanconi's type)

Summary Cytogenetic investigations were performed in a 10 year-old girl with clinical features of Fanconi's anaemia, i.e.: growth retardation, skin pigmentation, bilateral absence of thumbs, anaemia, leukopenia, etc. A variety of structural anomalies as chromatid gaps and exchanges, chromatid and isochromatid breaks were observed. The same type of chromosome anomalies was found in the parents and in the younger sister of the proposita, the older sister being karyotypically normal.Dermatoglyphic investigations revealed in the proposita the absence of t triradius on both palms and an increased mean ridge count, increased also in all the family members. Genetic implications and possible mechanisms of chromosomal aberrations are discussed.This investigation was supported by a grant from C.N.R., Italy.Professor of Child Health.     

Liver protection by bis(maltolato)zinc(II) complex.

The aim of this study was to perform screening of a novel drug for treating liver injury. Bis(maltolato)zinc(II) complex [Zn(Mal)(2)], which was previously reported to possess insulinomimetic activity, was found to have potency against experimentally induced liver injury both in vitro and in vivo. Cultured rat hepatocytes were treated with bromobenzene for 24 h to induce cellular injury. Zn(Mal)(2) of various concentrations was added along with bromobenzene in order to evaluate the hepatoprotective activity of Zn(Mal)(2) in vitro. The number of viable hepatocytes decreased by 42% in the culture with bromobenzene. However, hepatocyte viability was maintained when Zn(Mal)(2) was added to the bromobenzene culture. The hepatoprotective activity of Zn(Mal)(2) in vivo was investigated using a concanavalin A-induced liver injury model in BALB/c mice. Changes in serum aminotransferase activities and the secretion of several cytokines were measured. The hepatoprotective effect of Zn(Mal)(2) was also demonstrated in vivo by the suppression of serum aspartate aminotransferase and alanine aminotransferase elevation. No significant changes in serum cytokines associated with the induction of hepatic damage were observed in the concanavalin A-induced injury model. However, examination of concanavalin A-treated mouse splenocytes revealed a dose-dependent suppression of cytokine secretions by Zn(Mal)(2). Zn(Mal)(2) possessed hepatoprotective activity and might exert its effect by a number of mechanisms.     

Total skin electron beam (TSEB) therapy in pediatric patients: A review of the literature

Aim

A literature review was undertaken to identify current TSEB therapy in pediatric patients.

Background

Total skin electron beam (TSEB) therapy is a method of irradiation with low energy electron beam dedicated to patients who have superficial skin lesions all over their body. Such skin malignancies are sparse among adults and even more uncommon with pediatric population.

Materials and methods

In this study, all reported case reports were summed up with a special emphasis on techniques used, doses prescribed and special shielding of critical organs. Moreover, potential problems that were encountered during TSEB irradiation of very young patients were depicted.

Results

The literature has described only seven case reports of children undergoing TSEB therapy. Most of them were infants; however, two adolescents were also treated. For all infants, general anesthesia was provided to allow safe and accurate TSEB irradiation. The prescribed dose varied from 16 Gy to 28 Gy depending on the irradiation schedule and patient condition. Usually, boost fields were applied to the scalp and perineum. Typical shields for fingernails, toenails and lenses were usually used.

Conclusion

This paper revealed that TSEB therapy may be considered as a palliative treatment for pediatric patients with leukemia cutis. However, its role is still unclear and should be further investigated.     

Triple alpha-genes (alpha alpha alpha anti3.7) in a patient with sickle cell anaemia.

This paper reports the case of a 17-year-old male student from the Jaizan area in south-western Saudi Arabia who had sickle cell anaemia and possessed three alpha-genes on one chromosome (alpha alpha alpha anti3.7) and two on the other. The clinical manifestations were severe, with frequent blood transfusion requirements and frequent episodes of painful crises, severe anaemia and tissue involvement. In comparison with age and sex-matched sickle cell anaemia patients with one alpha-gene deletion (-alpha/alpha alpha), or a normal alpha-gene arrangement (alpha alpha/alpha alpha), a more severe disease presentation was obvious in the propositus. It is suggested that with the surplus alpha-globin chains, more severe haematological and clinical abnormalities occur, these influence the phenotypic expression of sickle cell anaemia. However, more patients with this type of gene arrangement must be studied before a definite conclusion can be reached regarding the influence of excess alpha-globin chains on the presentation of sickle cell anaemia.     

Congenital dyserytropoietic anaemia, type II (HEMPAS) in three siblings

These siblings of a Czech family aged 21, 19 and 6 years, respectively, with congenital dyserythropoietic anemia, type II, (HEMPAS) are reported. In two elder siblings ferrokinetic studies revealed a rapid plasma 59Fe clearance, markedly decreased erythrocyte incorporation and shortened 51Cr red-cell survival. Direct anti-globulin test was found positive in one of them. Further investigations revealed low values of blood plasma cholesterol, total lipids, beta-lipoproteins, beta-carotine and vitamin E and A as well as low values of the prothrombin complex. Liver biopsy demonstrated siderosis and disseminated intravascular coagulation in the liver in both patients. The possible reasons for these humoral aberrations are discussed.     

Bis(6-ethylpicolinato)oxovanadium(IV) complex with normoglycemic activity in KK-A(y) mice.

A novel bis(6-ethylpicolinato)(H(2)O)oxovanadium(IV) complex (VO(6epa)(2) x (H(2)O)) was prepared and its structure was revealed by X-ray analysis (space group Pc(#7), a=10.838(2), b=11.148(5), c=16.642(3) A, and Z=2). Because VO(6epa)(2) x (H(2)O) exhibited higher in vitro insulinomimetic activity compared to that of vanadyl sulfate in terms of inhibition of free fatty acid (FFA) release from isolated rat adipocytes in the presence of epinephrine, its in vivo effect on whether the complex has a blood glucose normalizing effect was examined in KK-A(y) mice, a model animal of type 2 diabetes mellitus. VO(6epa)(2) x (H(2)O) was found to normalize the high blood glucose levels of KK-A(y) mice when given intraperitoneally at doses of 49 micromol/kg body weight for the first 4 days and then 39 micromol/kg body weight for 10 days. In addition, VO(6epa)(2) x (H(2)O) improved glucose tolerance ability as examined by the oral glucose test and seemed to have little toxicity in terms of serum parameters. VO(6epa)(2) x (H(2)O) showed higher normoglycemic activity than bis(6-methylpicolinato)oxovanadium(IV) (VO(6mpa)(2)) at the same dose. These results indicated that greater enhancement of the blood glucose normalizing effect in KK-A(y) mice by ethyl substitution compared to methyl substitution may be due to its being more strongly lipophilic.