How does hormone transition in transgender women change body composition, muscle strength and haemoglobin? Systematic review with a focus on the implications for sport participation.

OBJECTIVES: We systemically reviewed the literature to assess how long-term testosterone suppressing gender-affirming hormone therapy influenced lean body mass (LBM), muscular area, muscular strength and haemoglobin (Hgb)/haematocrit (HCT). DESIGN: Systematic review. DATA SOURCES: Four databases (BioMed Central, PubMed, Scopus and Web of Science) were searched in April 2020 for papers from 1999 to 2020. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Eligible studies were those that measured at least one of the variables of interest, included transwomen and were written in English. RESULTS: Twenty-four studies were identified and reviewed. Transwomen experienced significant decreases in all parameters measured, with different time courses noted. After 4 months of hormone therapy, transwomen have Hgb/HCT levels equivalent to those of cisgender women. After 12 months of hormone therapy, significant decreases in measures of strength, LBM and muscle area are observed. The effects of longer duration therapy (36 months) in eliciting further decrements in these measures are unclear due to paucity of data. Notwithstanding, values for strength, LBM and muscle area in transwomen remain above those of cisgender women, even after 36 months of hormone therapy. CONCLUSION: In transwomen, hormone therapy rapidly reduces Hgb to levels seen in cisgender women. In contrast, hormone therapy decreases strength, LBM and muscle area, yet values remain above that observed in cisgender women, even after 36 months. These findings suggest that strength may be well preserved in transwomen during the first 3 years of hormone therapy.

PF-07059013: A Noncovalent Modulator of Hemoglobin for Treatment of Sickle Cell Disease.

Sickle cell disease (SCD) is a genetic disorder caused by a single point mutation (ß6 Glu → Val) on the ß-chain of adult hemoglobin (HbA) that results in sickled hemoglobin (HbS). In the deoxygenated state, polymerization of HbS leads to sickling of red blood cells (RBC). Several downstream consequences of polymerization and RBC sickling include vaso-occlusion, hemolytic anemia, and stroke. We report the design of a noncovalent modulator of HbS, clinical candidate PF-07059013 (23). The seminal hit molecule was discovered by virtual screening and confirmed through a series of biochemical and biophysical studies. After a significant optimization effort, we arrived at 23, a compound that specifically binds to Hb with nanomolar affinity and displays strong partitioning into RBCs. In a 2-week multiple dose study using Townes SCD mice, 23 showed a 37.8% (±9.0%) reduction in sickling compared to vehicle treated mice. 23 (PF-07059013) has advanced to phase 1 clinical trials.

Effect of Low-Dose Ferrous Sulfate vs Iron Polysaccharide Complex on Hemoglobin Concentration in Young Children With Nutritional Iron-Deficiency Anemia: A Randomized Clinical Trial.

Importance: Iron-deficiency anemia (IDA) affects millions of persons worldwide, and is associated with impaired neurodevelopment in infants and children. Ferrous sulfate is the most commonly prescribed oral iron despite iron polysaccharide complex possibly being better tolerated. Objective: To compare the effect of ferrous sulfate with iron polysaccharide complex on hemoglobin concentration in infants and children with nutritional IDA. Design, Setting, and Participants: Double-blind, superiority randomized clinical trial of infants and children aged 9 to 48 months with nutritional IDA (assessed by history and laboratory criteria) that was conducted in an outpatient hematology clinic at a US tertiary care hospital from September 2013 through November 2015; 12-week follow-up ended in January 2016. Interventions: Three mg/kg of elemental iron once daily as either ferrous sulfate drops or iron polysaccharide complex drops for 12 weeks. Main Outcomes and Measures: Primary outcome was change in hemoglobin over 12 weeks. Secondary outcomes included complete resolution of IDA (defined as hemoglobin concentration >11 g/dL, mean corpuscular volume >70 fL, reticulocyte hemoglobin equivalent >25 pg, serum ferritin level >15 ng/mL, and total iron-binding capacity <425 µg/dL at the 12-week visit), changes in serum ferritin level and total iron-binding capacity, adverse effects. Results: Of 80 randomized infants and children (median age, 22 months; 55% male; 61% Hispanic white; 40 per group), 59 completed the trial (28 [70%] in ferrous sulfate group; 31 [78%] in iron polysaccharide complex group). From baseline to 12 weeks, mean hemoglobin increased from 7.9 to 11.9 g/dL (ferrous sulfate group) vs 7.7 to 11.1 g/dL (iron complex group), a greater difference of 1.0 g/dL (95% CI, 0.4 to 1.6 g/dL; P < .001) with ferrous sulfate (based on a linear mixed model). Proportion with a complete resolution of IDA was higher in the ferrous sulfate group (29% vs 6%; P = .04). Median serum ferritin level increased from 3.0 to 15.6 ng/mL (ferrous sulfate) vs 2.0 to 7.5 ng/mL (iron complex) over 12 weeks, a greater difference of 10.2 ng/mL (95% CI, 6.2 to 14.1 ng/mL; P < .001) with ferrous sulfate. Mean total iron-binding capacity decreased from 501 to 389 µg/dL (ferrous sulfate) vs 506 to 417 µg/dL (iron complex) (a greater difference of -50 µg/dL [95% CI, -86 to -14 µg/dL] with ferrous sulfate; P < .001). There were more reports of diarrhea in the iron complex group than in the ferrous sulfate group (58% vs 35%, respectively; P = .04). Conclusions and Relevance: Among infants and children aged 9 to 48 months with nutritional iron-deficiency anemia, ferrous sulfate compared with iron polysaccharide complex resulted in a greater increase in hemoglobin concentration at 12 weeks. Once daily, low-dose ferrous sulfate should be considered for children with nutritional iron-deficiency anemia. Trial Registration: clinicaltrials.gov Identifier: NCT01904864.

Deworming drugs for soil-transmitted intestinal worms in children: effects on nutritional indicators, haemoglobin, and school performance.

BACKGROUND: The World Health Organization (WHO) recommends treating all school children at regular intervals with deworming drugs in areas where helminth infection is common. As the intervention is often claimed to have important health, nutrition, and societal effects beyond the removal of worms, we critically evaluated the evidence on benefits. OBJECTIVES: To summarize the effects of giving deworming drugs to children to treat soil-transmitted helminths on weight, haemoglobin, and cognition; and the evidence of impact on physical well-being, school attendance, school performance, and mortality. SEARCH METHODS: We searched the Cochrane Infectious Diseases Group Specialized Register (14 April 2015); Cochrane Central Register of Controlled Trials (CENTRAL), published in the Cochrane Library (2015, Issue 4); MEDLINE (2000 to 14 April 2015); EMBASE (2000 to 14 April 2015); LILACS (2000 to 14 April 2015); the metaRegister of Controlled Trials (mRCT); and reference lists, and registers of ongoing and completed trials up to 14 April 2015. SELECTION CRITERIA: We included randomized controlled trials (RCTs) and quasi-RCTs comparing deworming drugs for soil-transmitted helminths with placebo or no treatment in children aged 16 years or less, reporting on weight, haemoglobin, and formal tests of intellectual development. We also sought data on school attendance, school performance, and mortality. We included trials that combined health education with deworming programmes. DATA COLLECTION AND ANALYSIS: At least two review authors independently assessed the trials, evaluated risk of bias, and extracted data. We analysed continuous data using the mean difference (MD) with 95% confidence intervals (CIs). Where data were missing, we contacted trial authors. We used outcomes at time of longest follow-up. The evidence quality was assessed using GRADE. This edition of the Cochrane Review adds the DEVTA trial from India, and draws on an independent analytical replication of a trial from Kenya. MAIN RESULTS: We identified 45 trials, including nine cluster-RCTs, that met the inclusion criteria. One trial evaluating mortality included over one million children, and the remaining 44 trials included a total of 67,672 participants. Eight trials were in children known to be infected, and 37 trials were carried out in endemic areas, including areas of high (15 trials), moderate (12 trials), and low prevalence (10 trials). Treating children known to be infectedTreating children known to be infected with a single dose of deworming drugs (selected by screening, or living in areas where all children are infected) may increase weight gain over the next one to six months (627 participants, five trials, low quality evidence). The effect size varied across trials from an additional 0.2 kg gain to 1.3 kg. There is currently insufficient evidence to know whether treatment has additional effects on haemoglobin (247 participants, two trials, very low quality evidence); school attendance (0 trials); cognitive functioning (103 participants, two trials, very low quality evidence), or physical well-being (280 participants, three trials, very low quality evidence). Community deworming programmesTreating all children living in endemic areas with a dose of deworming drugs probably has little or no effect on average weight gain (MD 0.04 kg less, 95% CI 0.11 kg less to 0.04 kg more; trials 2719 participants, seven trials, moderate quality evidence), even in settings with high prevalence of infection (290 participants, two trials). A single dose also probably has no effect on average haemoglobin (MD 0.06 g/dL, 95% CI -0.05 lower to 0.17 higher; 1005 participants, three trials, moderate quality evidence), or average cognition (1361 participants, two trials, low quality evidence).Similiarly, regularly treating all children in endemic areas with deworming drugs, given every three to six months, may have little or no effect on average weight gain (MD 0.08 kg, 95% CI 0.11 kg less to 0.27 kg more; 38,392 participants, 10 trials, low quality evidence). The effects were variable across trials; one trial from a low prevalence setting carried out in 1995 found an increase in weight, but nine trials carried out since then found no effect, including five from moderate and high prevalence areas.There is also reasonable evidence that regular treatment probably has no effect on average height (MD 0.02 cm higher, 95% CI 0.14 lower to 0.17 cm higher; 7057 participants, seven trials, moderate quality evidence); average haemoglobin (MD 0.02 g/dL lower; 95% CI 0.08 g/dL lower to 0.04 g/dL higher; 3595 participants, seven trials, low quality evidence); formal tests of cognition (32,486 participants, five trials, moderate quality evidence); exam performance (32,659 participants, two trials, moderate quality evidence); or mortality (1,005,135 participants, three trials, low quality evidence). There is very limited evidence assessing an effect on school attendance and the findings are inconsistent, and at risk of bias (mean attendance 2% higher, 95% CI 4% lower to 8% higher; 20,243 participants, two trials, very low quality evidence).In a sensitivity analysis that only included trials with adequate allocation concealment, there was no evidence of any effect for the main outcomes. AUTHORS' CONCLUSIONS: Treating children known to have worm infection may have some nutritional benefits for the individual. However, in mass treatment of all children in endemic areas, there is now substantial evidence that this does not improve average nutritional status, haemoglobin, cognition, school performance, or survival.

Long-term results of radiation therapy oncology group 9903: a randomized phase 3 trial to assess the effect of erythropoietin on local-regional control in anemic patients treated with radiation therapy for squamous cell carcinoma of the head and neck.

PURPOSE: This paper reports long-term results of RTOG 9903, to determine whether the addition of erythropoietin (EPO) would improve the outcomes of radiation therapy (RT) in mildly to moderately anemic patients with head and neck squamous cell carcinoma (HNSCCa). METHODS AND MATERIALS: The trial included HNSCCa patients treated with definitive RT. Patients with stage III or IV disease received concomitant chemoradiation therapy or accelerated fractionation. Pretreatment hemoglobin levels were required to be between 9.0 and 13.5 g/dL (12.5 g/dL for females). EPO, 40,000 U, was administered weekly starting 7 to 10 days before RT was initiated in the RT + EPO arm. RESULTS: A total of 141 of 148 enrolled patients were evaluable. The baseline median hemoglobin level was 12.1 g/dL. In the RT + EPO arm, the mean hemoglobin level at 4 weeks increased by 1.66 g/dL, whereas it decreased by 0.24 g/dL in the RT arm. With a median follow-up of 7.95 years (range: 1.66-10.08 years) for surviving patients and 3.33 years for all patients (range: 0.03-10.08 years), the 5-year estimate of local-regional failure was 46.2% versus 39.4% (P=.42), local-regional progression-free survival was 31.5% versus 37.6% (P=.20), and overall survival was 36.9% versus 38.2% (P=.54) for the RT + EPO and RT arms, respectively. Late toxicity was not different between the 2 arms. CONCLUSIONS: This long-term analysis confirmed that despite the ability of EPO to raise hemoglobin levels in anemic patients with HNSCCa, it did not improve outcomes when added to RT. The possibility of a detrimental effect of EPO could not be ruled out.

Association among acrylamide, blood insulin, and insulin resistance in adults.

OBJECTIVE: Exposure to acrylamide in foodstuffs and smoking has become a worldwide concern. The effect of acrylamide on glucose homeostasis is not known. The goal of the present study was to test the hypothesis that trace acrylamide exposure might be independently associated with both reduced blood insulin and reduced insulin resistance. RESEARCH DESIGN AND METHODS: We examined 1,356 participants with reliable measures of glucose homeostasis and Hb adducts of acrylamide (HbAA) and glycidamide from the National Health and Nutrition Examination Survey, 2003-2004. Glucose homeostasis was assessed by the measurement of plasma glucose, serum insulin, and the homeostasis model assessment of insulin resistance (HOMA-IR). RESULTS: In a linear regression model, a 1-unit increase in log HbAA was associated with a decrease in serum insulin (beta coefficient = -0.20 +/- 0.05, P = 0.001) and HOMA-IR (beta coefficient = -0.23 +/- 0.05, P < 0.001). After HbAA concentrations were divided into quartiles in the fully adjusted models, the adjusted serum insulin level and HOMA-IR significantly decreased across quartiles of HbAA (P(trend) < 0.001 for both). In subgroup analysis, the association of HbAA levels with HOMA-IR and insulin levels was stronger in subjects who were white or had ever smoked or in subjects with a lower education level or a BMI <25 or >30 kg/m(2). CONCLUSIONS: Acrylamide is associated with reduced serum insulin levels in adults. Further clinical and animal studies are warranted to clarify the putative causal relationship.

Impact of hyperglycemic control on left ventricular myocardium. A molecular and cellular basic study in a diabetic rat model.

This experimental study investigated the impact of hyperglycemic control on left ventricular (LV) function using a model of diabetes mellitus (DM) (induced by streptozocin 60 mg/kg). Sixteen adult-Sprague Dawley rats were divided into group 1 (poor hyperglycemic control, n = 8) and group 2 (good hyperglycemic control, n = 8). Diabetic rats and 8 healthy rats serving as controls (group 3) were sacrificed on day 28 after DM induction. The results demonstrated that HbA(1C) on day 28 was higher in group 1 than in groups 2 and 3 (P < 0.0001). The mRNA expressions of MMP-9 and endothelin-1 were elevated in group 1 compared with that in groups 2 and 3 (P < 0.05), whereas PGC-1alpha and eNOS were lower in group 1 than in groups 2 and 3 (P < 0.05). The number of apoptotic nuclei was higher in group 1 than in groups 2 and 3 (P < 0.01). The integrated area (microm(2)) of connexin43 (Cx43), Cx43 protein expression, and LV function were lower in group 1 than in groups 2 and 3 (P < 0.05). Moreover, PKC-epsilon expression in the mitochondrial compartment was decreased in group 1 compared to that in groups 2 and 3 (P < 0.005).

Anemia during sequential induction chemotherapy and chemoradiation for head and neck cancer: the impact of blood transfusion on treatment outcome.

PURPOSE: Sequential treatment (chemotherapy followed by concomitant chemoradiation; CCRT) is increasingly being used for radical treatment of squamous cell cancer of the head and neck (SCCHN), which results in increased myelosuppression. In this study, we review the incidence of anemia and the effect of a policy of hemoglobin (Hb) maintenance by blood transfusion on disease outcomes in these patients. METHODS AND MATERIALS: Retrospective review of the records of patients with SCCHN treated with sequential CCRT formed the basis of this study. The incidence of anemia and statistics on blood transfusion were documented. For the purpose of outcome analyses, patients were divided into four categories by (1) transfusion status, (2) nadir Hb concentration, (3) number of transfusion episodes, and (4) number of units of blood transfused (NOUT). Data on 3-year locoregional control (LRC), relapse-free survival (RFS), disease-specific survival (DSS), and overall survival (OS) were analyzed. RESULTS: One hundred and sixty-nine patients were identified. The median follow-up was 23.6 months. The RFS (52% vs. 41%, p = 0.03), DSS (71% vs. 66%, p = 0.02), and OS (58% vs. 42% p = 0.005) were significantly better for patients who did not have a transfusion vs. those who did. The LRC, RFS, DSS, and OS were also significantly better for patients with nadir Hb level >12 vs. <12 g/dL and NOUT 1-4 vs. >4. CONCLUSION: Our study seems to suggest that blood transfusion during radical treatment for SCCHN might be detrimental. Further research should be undertaken into the complex interactions among tumor hypoxia, anemia, and the treatment of anemia before making treatment recommendations.

Defining the role of incretin mimetic therapy in the management of type 2 diabetes.

Diabetes mellitus affects 21 million Americans; an additional 41 million individuals in this country have impaired glucose tolerance. These individuals are at high risk for developing not only diabetes, but eventually dying from the cardiovascular complications associated with chronic exposure to hyperglycemia. Not only do patients with diabetes carry a 1.5- to 4.5-fold increased risk of cardiovascular mortality, any microvascular complications they develop such as retinopathy, neuropathy, and nephropathy can have a profoundly negative effect on their quality of life. Even mild hyperglycemia is associated with macrovascular disease. Similarly, hyperglycemia that occurs concurrently during an acute myocardial infarction or stroke is associated with worse outcomes. Therefore, evidence suggests that both chronic and acute hyperglycemia lead to higher morbidity and mortality. As people age, their 2-hour postchallenge blood glucose level typically increases, often independent of their fasting glucose level. At diagnosis, 25% of patients with type 2 diabetes have normal fasting glucose levels. The incidence of isolated impaired glucose tolerance is approximately 3 times greater than isolated impaired fasting glucose. Therefore, most patients with asymptomatic diabetes have isolated postchallenge hyperglycemia. A growing body of literature supports targeting postprandial hyperglycemia to lower glycosylated hemoglobin (A1C) levels and reduce microvascular and macrovascular complications associated with chronic hyperglycemia. This article will evaluate a typical patient case and strategies employed by the patient and health care provider.

Effect of glycation of hemoglobin on its interaction with trifluoperazine.

Trifluoperazine (TFZ), a phenothiazine drug, penetrates into human erythrocytes and releases oxygen by interaction with hemoglobin. TFZ-induced oxygen release from hyperglycemic erythrocytes isolated from diabetic patients is considerably less compared to that from the cells of normoglycemic individuals. In diabetes mellitus, hemoglobin is significantly glycated by glucose. Non-glycated hemoglobin, HbA0 and its major glycated analog, HbA1c have been separated from the blood samples of diabetic patients. TFZ releases considerable amount of oxygen from HbA0, but very little from HbA1c. Spectrofluorimetric studies reveal that TFZ forms excited state complexes with both HbA0 and HbAlc. Titration of HbA0 with TFZ in a spectrophotometric study exhibits two isosbestic points. Similar experiment with HbAlc causes gradual loss of the Soret peak without appearance of any isosbestic point indicating a possibility of heme loss during interaction, which is also supported by gel filtration experiment and SDS-PAGE experiment followed by heme staining. The results suggest that drug action on hemoglobin is influenced by glycation-induced structural modification of the protein.

Properties of normal and glycated human hemoglobin in presence and absence of antioxidant.

We present a novel approach to study properties of normal (HbA) and nonenzymatically glycated (HbA(Ic), HbA(Ia+b)) human hemoglobin using absorption spectroscopy and differential scanning calorimetry. The effect of the presence of the antioxidant fisetin on glycation of HbA is studied. Here, absorption spectroscopy has been fruitfully exploited to observe the formation of the glycated hemoglobin. With the differential scanning calorimetry, we studied the thermal unfolding of the protein hemoglobin at various conditions. The thermogram of the pure HbA showed two transition regions, with the occurrence of a partially unfolded intermediate state (the formation of which is mainly reversible) prior to complete denaturation (irreversible process). The denaturation temperature of HbA was found to be strongly dependent on the heating rate. Furthermore, there is a significant cooperativity between the two transition regions in pure HbA. The overall denaturation for the glycated hemoglobin takes place at a lower temperature, suggesting a decrease in the stability of the protein when it is glycated. In presence of fisetin, glycation is inhibited to a certain extent and the thermograms match well with that of normal HbA. Implications of the results are discussed.

The metabolic effects of troglitazone in patients with diabetes and end-stage renal disease.

Thiazolidinediones (TZD) are effective agents for the treatment of hyperglycemia, and appear ideal in diabetic patients with progressive or end-stage renal disease because of its predominant hepatic clearance. Troglitazone, the first available TZD for clinical use, was withdrawn due to safety concerns; however, studies completed with this agent can provide a better understanding of the class effect of TZDs. This study was an open-label, controlled clinical trial examining the safety and efficacy of troglitazone in type 2 diabetic patients with end-stage renal disease (ESRD). Twelve subjects were randomized to parallel study groups and treated for 6 mo with or without troglita-zone at a maximum dose of 600 mg/d in addition to continuing their previous diabetes medications (insulin or sulfonylurea). The results showed no significant differences in glycemic control with or without troglit-azone treatment for 6 mo. However, there was a significant reduction in insulin dosage with troglitazone treatment (22.9 +/- 7.3 units/d) than without troglita-zone treatment (54 +/- 12.9 units/d) (p < 0.05), as well as the change in the insulin dosage from baseline between the two groups (troglitazone, -8.4 units vs control, +4.3 units, p < 0.05). Weight changes and aspartate amino-transferase levels greater than 1.5 times the upper limit of normal were not observed in participants of either treatment group. This study demonstrates that troglit-azone was safe and effective for the treatment of hyper-glycemia in patients requiring dialysis, and strongly supports the clinical use of currently available TZDs in diabetic patients with renal failure.

Allosteric effects of chloride ions at the intradimeric alpha1beta1 and alpha2beta2 interfaces of human hemoglobin.

The structural transition induced by ligand binding in human hemoglobin encompasses quaternary structure changes at the interfaces between the two alphabeta dimers. In contrast, the interfaces between alpha and beta subunits within the same dimer (i.e., alpha1beta1 and alpha2beta2 interfaces) are structurally invariant. Previous work from this laboratory using NMR spectroscopy has identified four sites at the intradimeric alpha1beta1 and alpha2beta2 interfaces that, although structurally invariant, experience significant changes in the rates of proton exchange upon ligand binding. These sites are Hisalpha103(G10) and Hisalpha122(H5) in each alpha subunit of the hemoglobin tetramer. In the present work, we show that the proton exchange at the Hisalpha103(G10) sites is affected by the interactions of hemoglobin with chloride ions. Increasing concentrations of chloride ions at pH 6.45 and at 37 degrees C enhance the exchange rate of the Hisalpha103(G10) N(epsilon 2) proton. The enhancement is greater in deoxygenated than in ligated hemoglobin. In the framework of the local unfolding model for proton exchange, these results suggest that the structural free energy and/or the proton transfer reactions at the Hisalpha103(G10) sites depend on the concentration of chloride ions. Therefore, the ligand-induced changes at the Hisalpha103(G10) sites are modulated by the allosteric effect of chloride ions on hemoglobin.

Inhibition of human hemoglobin autoxidation by sodium n-dodecyl sulphate.

The effect of sodium n-dodecyl sulphate (SDS) on hemoglobin autoxidation was studied in the presence of a 100 mM phosphate buffer (pH 7.0) by different methods. These included spectrophotometry, fluorescence technique, cyclic voltametry, differential scanning calorimetry, and densitometry. Spectroscopic studies showed that SDS concentrations up to 1 mM increased deoxy-, decreases oxy-, and had no significant effect on the met- conformation of hemoglobin. Therefore, a SDS concentration up to 1 mM increased the deoxy form of hemoglobin as the folded, compact state and decreases the oxy conformation. The turbidity measurements and differential scanning calorimetry techniques indicated a more stable conformation for hemoglobin in the presence of SDS up to 1 mM. Electrochemical studies also confirmed a more difficult oxidation under these conditions. The induction of the deoxy form in the presence of SDS was confirmed by densitometry techniques. The compact structure of deoxyhemoglobin blocks the formation of met-conformation in low SDS concentrations.

Toxicidad del aluminio sobre el sistema eritropoyético: mecanismos involucrados / Aluminum toxicity in erythropoiesis: related mechanisms

En la presente revisión se expone una discusión de resultados publicados que involucran al aluminio como uno de los factores que pueden afectar al sistema eritropoyético. En células K562 se determinó que el receptor específico para transferrina presente en la membrana de células eritroides posee afinidad similar para esa proteína cuando transporta hierro o aluminio y que la captación celular de hierro disminuye por la presencia de aluminio. Este metal provoca, en células eritroides, una disminución de la síntesis de hemoglobina. En base a los resultados obtenidos en estudios experimentales in vitro e in vivo se postulan dos hipótesis que involucran: la interferencia del aluminio con la captación y/o utilización celular de hierro y la interacción del aluminio con componentes de la membrana celular. Este último hecho afectaría no sólo la estructura de la membrana sino también sus características fisicoquímicas y/o sus funciones, como la unión de ligandos a sus receptores específicos de la superficie de la membrana celular. Los mecanismos que se discuten permiten adjudicar a la presencia de aluminio en el organismo tanto la inhibición del crecimiento y/o la diferenciación de células progenitoras eritroides como las diferentes alteraciones morfológicas de eritrocitos maduros (AU)

Alteration of radiation-induced hematotoxicity by amifostine.

PURPOSE: To investigate whether amifostine can reduce radiation hematotoxicity. PATIENTS AND METHODS: Seventy-three patients undergoing radiotherapy for squamous cell carcinoma of the head and neck at the university clinics of Freiburg, Heidelberg, and Erlangen were evaluated. All received 60 Gy (50-70 Gy) at 5 x 2 Gy fractions per week employing standard techniques. Thirty-five were randomized to receive 200 mg/m(2) amifostine i.v. 30 min before radiation; 38 served as control patients. Blood counts (total n = 501) were determined before, during, and while completing radiotherapy. Changes of leukocyte, platelet, and hemoglobin levels were determined and compared using the t test. RESULTS: The blood hemoglobin level and the platelet count were not affected by irradiation, for either the amifostine-treated or control patients. Similarly, the leukocyte counts of amifostine-treated patients did not change during irradiation. However, control patients experienced a decrease in leukocyte count from 8.1 x 10(3)/mm(3) to 5.8 x 10(3)/mm(3) (difference: 2.3 x 10(3)/mm(3)). This seems to be line specific: Whereas amifostine does not affect lymphocyte count, a radiation-induced decrease of neutrophil granulocytes seems to be prevented. CONCLUSION: Amifostine protects from radiation hematotoxicity, particularly affecting the granulocytopoiesis. These data confirm results from our former study.

A phase I study of RSR13, a radiation-enhancing hemoglobin modifier: tolerance of repeated intravenous doses and correlation of pharmacokinetics with pharmacodynamics.

PURPOSE: Preclinical studies indicate that RSR13 oxygenates and radiosensitizes hypoxic solid tumors by decreasing the oxygen (O(2))-binding affinity of hemoglobin (Hb). A Phase I open-label, multicenter dose and frequency escalation study was conducted to assess the safety, tolerance, pharmacokinetics, and pharmacodynamic effect of daily RSR13 administration to cancer patients receiving concurrent palliative radiotherapy (RT). METHODS AND MATERIALS: Eligibility criteria included the following: ECOG performance status < or =2; resting and exercise arterial oxygen saturation (SaO(2)) > or =90%; an indication for palliative RT, 20-40 Gy in 10-15 fractions. RSR13 was administered i.v. via central vein over 60 min immediately before RT. Patients received supplemental O(2) via nasal cannula at 4 L/min during RSR13 infusion and RT. Plasma, red blood cell (RBC), and urine RSR13 concentrations were assayed. The pharmacodynamic effect of RSR13 on Hb-O(2) binding affinity was quantified by multipoint tonometry and expressed as an increase in p50, defined as the partial pressure of O(2) that results in 50% SaO(2). The RSR13 dose in the first cohort was 75 mg/kg once a week for two doses; successive cohorts received higher, more frequent doses up to 100 mg/kg/day for 10 days during RT. RESULTS: Twenty patients were enrolled in the study. Repeated daily doses of RSR13 were generally well tolerated. Two adverse events of note occurred: (1) A patient with pre-existing restrictive lung disease had transient persistent hypoxemia after the sixth RSR13 dose; (2) a patient with a recurrent glioma receiving high-dose corticosteroids had edema after the seventh RSR13 dose, likely due to the daily high-volume fluid infusions. Both patients recovered to baseline status with conservative management. Maximum pharmacodynamic effect occurred at the end of RSR13 infusion and was proportional to the RBC RSR13 concentration. After an RSR13 dose of 100 mg/kg, the peak increase in p50 averaged 8.1 mm Hg, consistent with the targeted physiologic effect, and then diminished with a half-life of approximately 5 h. CONCLUSIONS: RSR13 was well tolerated in daily doses up to 100 mg/kg administered for 10 days during RT. The combined administration of RSR13 with 4 L/min supplemental O(2) yielded pharmacodynamic conditions in which hypoxic tumor radiosensitization can occur. Ongoing Phase II and Phase III studies are evaluating the combination of RT and RSR13 for selected indications, including primary brain tumors, brain metastases, and non-small-cell lung cancer.

A comparative study of insulin lispro and human regular insulin in patients with type 2 diabetes mellitus and secondary failure of oral hypoglycemic agents.

OBJECTIVE: To compare the effects of insulin lispro (LP) and human regular insulin (HR) when given twice daily with NPH insulin on glycemic control (HbA1c), daily blood glucose profiles and rates of hypoglycemia in patients with type 2 diabetes mellitus after failure to respond to sulfonylurea drugs. RESEARCH DESIGN AND METHODS: A 5.5-month randomized, open-label, parallel study of 148 patients receiving either LP (n = 70) or HR (n = 78). Eight-point blood glucose profiles and HbA1c measurements were collected at baseline, 1.5, 3.5 and 5.5 months. RESULTS: Two-hour post-breakfast and 2-hour post-supper blood glucose levels (means [and standard errors]) were significantly lower for LP than for HR at the end point (9.5 [0.4] mmol/L v. 10.9 [0.4] mmol/L and 8.4 [0.4] mmol/L v. 9.7 [0.4] mmol/L, respectively, p = 0.02 in both cases). HbA1c improved from 10.5% (0.2%) (LP) and 10.3% (0.2%) (HR) to 8.0% (0.1%). Hypoglycemia rates were similar during the day; however, there was an overnight trend to reduced rates with LP (0.08 [0.03] episodes/30 d v. 0.16 [0.04] episodes/30 d, p = 0.057). Quality-of life assessment showed significant improvement (p < 0.05) in the diabetes-related worry scale for LP subjects whereas HR subjects slightly worsened. CONCLUSIONS: With traditional twice-daily insulin administration algorithms, LP improves 2-hour postprandial glucose levels, quality of life and overnight hypoglycemia rates while delivering an equivalent level of glycemic control (HbA1c) compared with HR to insulin-naïve patients with type 2 diabetes who require insulin.

Redox concerns in the use of acellular hemoglobin-based therapeutic oxygen carriers: the role of plasma components.

Within the past decade, most research efforts in the red blood cell substitute area have revolved about the development of acellular hemoglobin-based oxygen carriers (HBOC) as clinical replacements and/or augmentation of human blood's carrying and delivery function. A major requirement for all HBOC is the maintenance of the heme-Fe+2 in this reduced state for normal physiological behavior. Oxidation of hemoglobin results in the formation of methemoglobin (heme-Fe+3). MetHb is unable to bind oxygen thus effectively lowering the carrying capacity of the Hb-based substitute. In addition, met Hb gives rise to free radicals that have the potential to cause endothelial and surrounding tissue damage. Results of this study suggest that the normal endogenous reducing agents of human plasma have the capacity to provide redox protection and stability to specific acellular-types of HBOC. The effectiveness of these reducing agents may be related to the formal reduction potential of the HBOC being considered. The choice of buffer for HBOC storage is critical and specific to the HBOC product.