Reduction of Leukopenia in Mice by « Viscum Album » Administration during Radiation and Chemotherapy

« Viscum album » extract, iscador, was found to reduce the lekocytopenia produced by radiation and cyclophosphamide treatment in animals. Weight loss due to radiation was considerably reduced by « Viscum album » extract whereas weight loss due to cyclophosphamide was not altered. Hemoglobin levels also were not affected by « Viscum album » extract administration. The results indicated that treatment with « Viscum album » extract reduces lymphocytopenia and hence could be used along with chemotherapy and radiation therapy.

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.

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.

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.

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.

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 Autoxidaiton 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.

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.

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.

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.

Haematological and spermatotoxic effects of ethylene glycol monomethyl ether in copper clad laminate factories

OBJECTIVES

To investigate the effects of ethylene glycol monomethyl ether (EGME) on haematology and reproduction in exposed workers.

METHODS

53 Impregnation workers from two factories that make copper clad laminate with EGME as a solvent were recruited as the exposed group. Another group of 121 lamination workers with indirect exposure to EGME was recruited as the control group. Environmental monitoring of concentrations of EGME in air and biological monitoring of urinary methoxyacetic acid (MAA) concentrations were performed. Venous blood was collected for routine and biochemical analyses. Semen was collected from 14 workers exposed to EGME for sperm analysis and was compared with 13 control workers.

RESULTS

Results of haematological examination showed that the haemoglobin, packed cell volume, and red blood cell count in the male workers exposed to EGME were significantly lower than in the controls. The frequency of anaemia in the exposed group (26.1%) was significantly higher than in the control group (3.2%). However, no differences were found between the female workers exposed and not exposed to EGME. After adjustment for sex, body mass index, and duration of employment, red blood cell count was significantly negatively associated with air concentrations of EGME, and haemoglobin, packed cell volume, and red blood cell count were significantly negatively associated with urinary concentrations of MAA. The pH of semen in the exposed workers was significantly lower than in the control workers, but there were no significant differences in the sperm count or sperm morphology between the exposed and control groups.

CONCLUSION

It can be concluded that EGME is a haematological toxin, which leads to anaemia in the exposed workers. However, the data from this study did not support the theory of a spermatotoxic effect of EGME.

Large-scale UK audit of blood transfusion requirements and anaemia in patients receiving cytotoxic chemotherapy

Cancer patients receiving cytotoxic chemotherapy often become anaemic and may require blood transfusions. A large-scale audit of patients with a variety of solid tumours receiving chemotherapy at 28 specialist centres throughout the UK was undertaken to quantify the problem. Data were available from 2719 patients receiving 3206 courses of cytotoxic chemotherapy for tumours of the breast (878), ovary (856), lung (772) or testis (213). Their mean age was 55 years (range 16-87). Overall, 33% of patients required at least one blood transfusion but the proportion varied from 19% for breast cancer to 43% for lung. Sixteen per cent of patients required more than one transfusion (7% for breast, 22% in lung). The mean proportion of patients with Hb < 11 g dl(-10 rose over the course of chemotherapy from 17% before the first cycle, to 38% by the sixth, despite transfusion in 33% of patients. Of the patients receiving transfusions, 25% required an inpatient admission and overnight stay. The most common symptoms reported at the time of transfusion were lethargy, tiredness and breathlessness. Further research is needed to evaluate the role of blood transfusions in patients receiving cytotoxic chemotherapy.

Rapid cortical hemoglobin deoxygenation after heroin and methadone injection in humans: a preliminary report

The short-term effects of intravenous opioids (heroin 20-300 mg, methadone 30-180 mg) on cortical hemoglobin oxygenation were examined by near infrared spectroscopy in ten opioid-dependent subjects and were compared with the effects of saline in ten age-matched normal controls. Heroin and methadone produced a rapid and dramatic decrease in cortical hemoglobin oxygenation. Saline had no effects. Opioid-induced acute deoxygenation of cortical hemoglobin is most likely associated with respiratory depression. Thorough medical monitoring is strongly recommended in intravenous opioid maintenance treatments.

Effect of a new starch-free bread on metabolic control in NIDDM patients

BACKGROUND AND AIM

The aim of the study was to evaluate the effect on blood glucose levels in non-insulin-dependent diabetics (NIDDM) of reduction of the carbohydrate content through the use of a new, almost starch-free type of bread (SF-bread). We only substituted the bread in the breakfast meal.

METHODS AND RESULTS

The study consisted of two parts: 1) a two-day randomized study of the effect of SF-bread on the morning blood glucose levels of NIDDM patients and 2) an open, crossover trial of three months duration where each patient was given SF- or ordinary bread. Ten patients participated in the first part and eight in the second part of the study. All patients had well established non insulin-dependent diabetes mellitus. In the first part of the study, the area under the curve describing time-dependent changes in blood glucose level after a standard breakfast was significantly lower in patients on SF-bread (182 +/- 154 Units; mean value +/- SD) than in the controls (630 +/- 258 Units; p < 0.00001). Peak blood glucose concentration was 14.8 +/- 2.3 mM on the control day and 11.6 +/- 1.7 mM on the SF-bread day (p < 0.001). In the second part of the study, the diet including SF-bread reduced fasting blood glucose from 13.3 +/- 3.5 mM to 10.2 +/- 2.0 mM (p < 0.006) and the fraction of HbA1c from 0.090 +/- 0.014 to 0.081 +/- 0.015 (p < 0.02). Similar changes were not seen on the ordinary diet. Serum cholesterol levels were significantly reduced by the SF-bread as compared to the ordinary diet (5.8 +/- 0.6 to 5.5 +/- 0.5 mM versus 5.7 +/- 0.8 to 5.8 +/- 0.7 mM; p < 0.05).

CONCLUSIONS

Substitution of ordinary bread with starch-free bread at breakfast causes significant improvements in blood glucose levels in NIDDM patients on both a short and long term basis. Possibly secondary to this, a favorable influence on lipid levels was noted.

Quality-of-life benefit in chemotherapy patients treated with epoetin alfa is independent of disease response or tumor type: results from a prospective community oncology study. Procrit Study Group

PURPOSE

To evaluate prospectively the effectiveness of epoetin alfa as an adjunct to chemotherapy in patients with cancer based on changes in quality-of-life parameters and hemoglobin levels, and to correlate these changes with antitumor response.

PATIENTS AND METHODS

Two thousand three hundred seventy patients with nonmyeloid malignancies who received chemotherapy were enrolled onto this study from 621 US community-based practices. Patients received epoetin alfa 10,000 U three times weekly, which could be increased to 20,000 U three times weekly depending on the hemoglobin response at 4 weeks. Treatment continued for a maximum of 16 weeks in patients who showed evidence of hematologic response.

RESULTS

Two thousand two hundred eighty-nine patients (97%) were eligible for efficacy analyses. Epoetin alfa therapy was associated with improved quality-of-life parameters; these improvements correlated significantly with hemoglobin levels and were independent of tumor response. Provider-reported Karnofsky performance scores did not correlate with the improved quality-of-life changes. Epoetin alfa therapy was also associated with a significant increase in hemoglobin levels and decrease in transfusion use. Tumor type, chemotherapy agent/regimen, prior chemotherapy, baseline hemoglobin level, and baseline erythropoietin level were not predictive of a positive response to treatment. Epoetin alfa was well tolerated.

CONCLUSION

Epoetin alfa appears to have a beneficial impact on patient-reported functional capacity and quality of life in patients with cancer who received chemotherapy independent of tumor response. Concordantly, epoetin alfa appeared to increase hemoglobin levels and decrease transfusion use. Patients responded across all tumor types. The results suggest that epoetin alfa effectively improves functional outcomes in patients with cancer who receive chemotherapy.

Stabilization of the T-state of ferrous human adult and fetal hemoglobin by Ln(III) complexes: a thermodynamic study

The effect of the lanthanide(III) complexes [Gd(1,4,7,10-tetraazacyclododecane-N,N',N", N"'-tetrakis(methylenephosphonate))]5- (Gd-DOTP) and La-DOTP on the oxygen binding and spectroscopic properties of human adult and fetal hemoglobin (HbA and HbF, respectively) has been investigated. The affinity of Gd-DOTP and La-DOTP for oxygenated HbA (HbAO2; KHbAO2 = 2.6 x 10(-3) M) is closely similar to that observed for Ln(III) complexes association to nitrosylated HbA (HbANO KHbANO = 1.8 x 10(-3) M) and to aquo-met HbA (met-HbA; Kmet-HbA = 1.9 x 10(-3) M), being lower than that determined for Gd-DOTP and La-DOTP binding to the deoxygenated form of the tetramer (HbAd; KHbAd = 3.0 x 10(-4) M). The affinity of Gd-DOTP for deoxygenated HbF (HbFd; KHbFd = 9.5 x 10(-4) M) and oxygenated HbF (HbFO2; KHbFO2 = 3.7 x 10(-3) M) is lower than that observed for Ln(III) complexes association to HbAd and HbAO2, respectively. Gd-DOTP and La-DOTP bind to HbA and HbF with a 1:1 stoichiometry per tetramer. Increasing Gd-DOTP and La-DOTP concentration, oxygen affinity for HbA decreases (i.e. P50 increases), this effect being minor for HbF. Upon binding of Ln(III) complexes to HbANO, the X-band EPR spectrum and the absorption spectrum in the Soret region display the characteristics which have been attributed to the T-state of the ligated tetramer. These results represent a clear cut evidence for the specific binding of Gd-DOTP and La-DOTP to the 2,3-D-glycerate bisphosphate (BPG) pocket (i.e. at the dyad axis, in between the beta-chains) of HbA and HbF. The effect of Ln(III) complexes on the ligand binding and spectroscopic properties of HbA and HbF is reminiscent that of BPG, the physiological modulator of human Hb action.

Comparison of effects of quinapril and metoprolol on glycaemic control, serum lipids, blood pressure, albuminuria and quality of life in non-insulin-dependent diabetes mellitus patients with hypertension. Swedish Quinapril Group

OBJECTIVE

To compare the long-term effects of the angiotensin-converting enzyme (ACE)-inhibitor quinapril and the cardioselective beta-adrenergic blocking agent metoprolol on glycaemic control, with glycosylated haemoglobin (HbA1c) as the principal variable, in non-insulin-dependent diabetes mellitus (NIDDM) patients with hypertension.

DESIGN

A randomized, double-blind, double-dummy, multicentre study during 6 months preceded by a 4 week wash-out and a 3 week run-in placebo period. Quinapril (20 mg) and metoprolol (100 mg, conventional tablets) were given once daily. No change was made in the treatment of diabetes (diet and hypoglycaemic agents).

SUBJECTS

Seventy-two patients fulfilling the criteria were randomized and entered the double-blind period. Twelve patients did not complete the study. Sixty patients, 26 on quinapril and 34 on metoprolol, were available for the final analysis.

MAIN OUTCOME MEASURES

The effect was assessed by changes in HbA1c, the fasting serum glucose and the post-load serum glucose, C-peptide and insulin levels during the oral glucose tolerance test.

RESULTS

In the quinapril group, the fasting serum glucose, oral glucose tolerance and the C-peptide and insulin responses, determined as the incremental area under the curves (AUC), showed no change, but the mean HbA1c level increased from 6.2 +/- 1.1% to 6.5 +/- 1.3% (P < 0.05). In the metoprolol group, the rise in the mean level of HbA1c, from 6.3 +/- 1.0% to 6.8 +/- 1.3% (P < 0.01), tended to be more marked than after quinapril, although there was no significant difference between the increments. The mean fasting serum glucose showed an increase from 9.1 +/- 1.9 mM to 10.1 +/- 2.8 mM (P < 0.01) which correlated significantly with the duration of diabetes (P < 0.01) and the increase in fasting serum triglycerides (P < 0.001). Moreover, in the metoprolol group we found significant decreases in the oral glucose tolerance as well as C-peptide and insulin responses to the glucose load.

CONCLUSIONS

Treatment with quinapril for 6 months appears to have advantages over metoprolol in NIDDM patients with hypertension. Although treatment with quinapril or metoprolol over 6 months was concomitant with a rise in the HbA1c, increased fasting blood glucose, decreased oral glucose tolerance and decreased C-peptide and insulin responses to a glucose challenge were observed only in patients treated with metoprolol.

Evaluation of biomarkers of survival response in hormone-refractory prostate cancer patients treated with suramin

Hormone-refractory prostate cancer (HRPC) patients often have nonmeasurable disease. In such patients, predictive biomarkers other than tumor response may be required to compare therapeutic effects. We examined the predictive value for survival of various clinical and laboratory parameters, including prostate-specific antigen (PSA), in HRPC patients treated with suramin. Data from 103 HRPC patients were analyzed using various survival analyses, the likelihood ratio approach, and logistic regression analyses. When pretreatment factors, percentage decrease in PSA at 4 weeks from start of treatment (deltaPSA), and updated survival data were fit by a multivariate Cox proportional hazards model, acid phosphatase, lactate dehydrogenase, and deltaPSA were significant, with risk ratios close to 1. There was a decrease in likelihood ratio with increasing APSA. A logistic regression model was developed to predict the probability of <1 year of survival from the start of treatment. Hemoglobin and deltaPSA were found to be significant variables. However, in view of the complexities involving the relationship between PSA expression and prostate cancer growth and possible selective effect of treatment on PSA, further prospective testing is necessary. Therefore, deltaPSA cannot necessarily be used as a biomarker for survival response in individual patients during the evaluation of the therapeutic response of HRPC to new antineoplastic drugs.

Pharmacologic hemoglobin reversal: the importance of lipid intermediaries and the proposed involvement of the cAMP and phosphatidylinositol second messenger systems

Humoral and microenvironmental influences have played a major role in recent research into reversing the Hb F to Hb A switch. Early research in this area focused on hormonal influences and showed both thyroid hormone and prolactin could induce small but statistically significant reversals in hemoglobin phenotype. Recent research has focused on the effect of certain lipids in this process. The current study shows a synergy between thyroid hormone and prolactin in inducing a significant switch in adult rat hemoglobin patterns toward the neonatal pattern. Further, it is hypothesized that this synergy is due to the hormones' effect on lipid intermediaries whose effect in turn are proposed to be mediated by the cAMP and phosphatidylinositol second messenger systems.

Correlation of magnetic resonance and oxygen microelectrode measurements of carbogen-induced changes in tumor oxygenation

PURPOSE

The aim of this work was to test the hypothesis that decreases in the linewidth of magnetic resonance (MR) water signals in tumors caused by oxygenating treatments are due to increases in capillary and venous oxygen saturation of hemoglobin, which are tightly coupled to increases in extravascular oxygen tension (pO2). To establish this link, changes measured by MR were compared to changes in tissue pO2 measured directly by oxygen microelectrodes during carbogen (95% O2/5% CO2) inhalation.

METHODS AND MATERIALS

Mammary adenocarcinomas (R3230AC) in nine rats were imaged at 4.7 Tesla. T1-weighted (TR = 200 ms, flip angle = 45 degrees) spectroscopic images of the water resonance in a single slice through each tumor were acquired with spectral resolution of 3.9 Hz and bandwidth of +/-1000 Hz. In the same slices in these tumors, microelectrode measurements were made using a non-Clark style oxygen electrode with a 350-micron tip. MR and microelectrode measurements were made during alternating periods of air and carbogen inhalation.

RESULTS

Water resonance linewidth decreased significantly during carbogen-induced hyperoxia. Paired Student's t-test analysis of microelectrode data indicated that pO2 was significantly (p < 0.05) increased as a result of carbogen inhalation. MR and microelectrode data averaged over each tumor demonstrated that decreased MR water signal linewidth is strongly correlated (r = 0.92, p < 0.05) with increased tumor pO2 levels.

CONCLUSION

Although tumor oxygenating agents increase response to radiation in rodent tumors, clinical studies have shown only marginal effects on the radiosensitivity of human tumors. This may be, in part, because the effects of tumor oxygenating treatments are highly heterogeneous both within each tumor and among a population of tumors. The noninvasive, high-resolution MR methods that are validated by the present work could guide the design of new and more effective tumor oxygenating agents and optimize treatments for individual patients.

Conformational fluctuations in deoxy hemoglobin revealed as a major contributor to anionic modulation of function through studies of the oxygenation and oxidation of hemoglobins A0 and Deer Lodge beta2(NA2)His --> Arg

Organisms rely on regulation at the molecular level, such as the allosteric regulation of hemoglobin (Hb) function by anions, to meet challenges presented by changing environmental and physiological conditions. A comparison of the effects of anions on oxygenation, oxidation, and sulfhydryl reactivity of Hb leads us to suggest that a large and significant part of the shift in oxygen affinity brought about by anion binding occurs as a result of increased conformational rigidity of the T state of deoxy Hb. As conformational rigidity increases, it becomes increasingly difficult for subunits in the deoxygenated T-state tetramer to assume higher oxygen affinity forms (T', T", T"'...) with less steric hindrance. The oxygen affinity reflects the average of the rapidly equilibrating conformations within the T state and is correspondingly decreased when anion levels are increased. The initial stage of the oxidation of Hb is relatively insensitive to steric alterations and thus reflects, primarily, the electronic aspects of the quaternary (T, T', T", T"'...) <--> equilibrium. We show that the reactivity of the sterically obscured sulfhydryl of beta93 Cys in deoxy Hb is much greater in chloride-free buffers than in buffers with added chloride. Anion-induced decreases in the extent and frequency of conformational fluctuations of subunits within the T-quaternary state thus reduce sulfhydryl reactivity as well as oxygen affinity. This parallel in anionic control of function allowed us to test, and disprove, the possibility that uncompensated positive charges in the central cavity of Hb Deer Lodge increase the frequency and extent of conformational fluctuations in its deoxy structure. This Hb variant exhibits increased anion sensitivity, increased oxygen affinity, and increased ease of oxidation, but without increased reactivity of its sulfhydryl groups, indicating that active-site alterations in deoxy Hb Deer Lodge are primarily electronic and not associated with increased conformational fluctuations within its T state. The restoration of normal properties in Hb Deer Lodge by addition of anions reinforces our conclusion that anionic control can be exerted through both steric and electronic alterations. The anionic control of fluctuations within the T state of Hb illustrates an important principle of macromolecular structure-function relationships: that functional regulation can be achieved by alterations in conformational rigidity.

Erythropoietin reduces anemia and transfusions after chemotherapy with paclitaxel and carboplatin

BACKGROUND

The authors report on anemia observed during preoperative paclitaxel and carboplatin chemotherapy in patients with advanced head and neck carcinoma and discuss how the use of recombinant human erythropoietin (r-HuEPO) ameliorates this anemia, reducing the need for subsequent packed red blood cell (PRBC) transfusions.

METHODS

Response to r-HuEPO was defined as reduced hemoglobin fall during preoperative chemotherapy and reduced transfusion requirements during surgery. Thirty-six patients with advanced head and neck carcinoma were evaluable after treatment with preoperative chemotherapy using paclitaxel and carboplatin. Group 1 was comprised of 14 patients who empirically received r-HuEPO at a dose of 150 U/kg 3 times per week for 3 weeks; in patients deemed nonresponders, the dose was increased to 300 U/kg and 450 U/kg in the subsequent courses. Group 2 was comprised of 22 patients who did not receive r-HuEPO.

RESULTS

During preoperative chemotherapy, the mean hemoglobin fall was 0.5 g/dL in Group 1 (P = 0.40). In Group 2 there was a statistically significant mean hemoglobin fall of 3.3 g/dL (P < 0.0001). There was also a nonstatistically significant trend toward fewer PRBC transfusions: none of 14 patients (0%) in Group 1 versus 4 of 22 patients (18%) in Group 2 (P = 0.141).

CONCLUSIONS

A significant fall in hemoglobin and an increase in the need for transfusions were observed in head and neck carcinoma patients receiving carboplatin and paclitaxel chemotherapy prior to surgery. Empiric r-HuEPO therapy appeared to prevent anemia and reduced the need for PRBC transfusions.

Hydroxyurea-induced denaturation of normal and sickle cell hemoglobins in vitro

Use of hydroxyurea (HU) to treat sickle cell disease is usually associated with increments in fetal hemoglobin (Hb F) production; however, in vitro studies show that HU may also induce hemoglobin denaturation. Whole blood samples from Hb AA, Hb AS, and Hb SS patients were treated in vitro with 100, 150, 200, 250, and 300 micrograms/mL HU, incubated at 30 degrees C for up to 12 days, and analyzed by high-performance liquid chromatography (HPLC). Hb AA levels show decrements of 91 to 14% with 100 micrograms/mL and 89 to 4% with 150 micrograms/mL after 12 days; 86 to 2% with 200 micrograms/mL after 10 days; 86 to 8% with 250 and 300 micrograms/mL after 8 days. Similar treatment and incubation times for Hb AS whole blood demonstrate that HU equally degrades the A and S components of Hb AS. A comparable approach for Hb SS whole blood samples, using a 300 micrograms/mL HU treatment, showed a hemoglobin denaturing pattern that went from 93% to 1% after 12 days. Globin chain analysis of these samples by reverse-phase HPLC showed that the denaturing effects occur mostly on the beta-globin chain.

Heterotropic effects of chloride on the ligation microstates of hemoglobin at constant water activity

Dimer-tetramer assembly reactions of the 10 CN-met ligation microstates of hemoglobin (Hb) were analyzed as a function of NaCl concentration while maintaining constant water activity by the addition of compensating sucrose. The assembly free energy for fully ligated cyanomet Hb and for fully oxygenated Hb becomes less favorable by 1.8 kcal when [NaCl] is increased from 0.08 to 0.7 M, whereas that of unligated Hb is practically insensitive to changes in [NaCl]. Values of 1.6 and 0.3 mol chloride release were found for the assembly of fully ligated and deoxy Hb, respectively; i.e., a net release of 1.3 mol chloride is coupled to the ligation of tetramers for both oxygen and cyanomet ligation. The ligation-linked salt component at constant water activity was evaluated to be 1.0 mol for the full oxygenation of the Hb tetramer in agreement with the overall value previously reported. When the detailed salt linkages accompanying all 16 stepwise cyanomet ligation reactions were experimentally resolved, only two "chloride" effects were found. The first chloride effect correlates with the ligation steps, which create tertiary constraint, and the second effect is coupled to the six switchpoints of quaternary T-->R transition. The distribution of these chloride effects agrees closely with predictions of the "symmetry rule mechanism." The total chloride release for CN-met ligation is in good agreement with that for oxygenation. Free energy contributions to assembly and cooperativity arising from the osmotic effects of chloride were found to be small for all ligation species.

Effect of recombinant human erythropoietin on the switchover from fetal to adult hemoglobin synthesis in preterm infants

To determine whether recombinant erythropoietin (r-HuEpo) administered to very low birth weight infants could increase hemoglobin F synthesis, or delay its developmentally programmed decline, we determined serially the synthesis of hemoglobins A and F in 15 preterm infants receiving either a placebo or r-HuEpo. There was no difference between the two groups in the proportion of hemoglobin F being synthesized in relation to postconceptional age.

Validated fluorimetric HPLC analysis of acetaldehyde in hemoglobin fractions separated by cation exchange chromatography: three new peaks associated with acetaldehyde

Stable hemoglobin-acetaldehyde adducts present in hemoglobin fractions separated by polyaspartic acid cation exchange chromatography were quantified by fluorimetric HPLC. The fluorescent species eluted from the HPLC was confirmed by mass spectrometry to be consistent with the expected product from reaction of acetaldehyde, 1,3-cyclohexanedione (CHD), and ammonium ion. Hemolysate (2.2 mM hemoglobin) was incubated in equivalent volumes of either phosphate-buffered saline or 5 mM acetaldehyde at 37 degrees C for 30 min and washed three times with H2O to remove free acetaldehyde and labile adducts before the injection of 14.7 mg hemoglobin onto the cation exchange column. Fluorimetric HPLC analysis of hemolysate samples either with or without in vitro reaction with acetaldehyde revealed that most acetaldehyde resides in the hemoglobin A0 fraction. The reaction with acetaldehyde in vitro resulted in a significant increase in fast-eluting minor hemoglobin species on cation exchange chromatography concomitant with increased acetaldehyde in the HbA1a+b, HbA1c, and HbA1-AcH fractions. We report three new cation exchange chromatographic peaks after reaction with acetaldehyde: HbA1-AcH-3, HbA1c-1, and HbA0-1. Each new peak was found to associate with a significant quantity of CHD-reactive acetaldehyde. These experiments provide additional evidence that stable adducts form between acetaldehyde and hemoglobin and that these adducts occur in multiple hemoglobin species separated by cation exchange chromatography. Further characterization and structural assignment of these species are warranted in view of their potential utility as markers for ethanol intake.

Short-term effects of felodipine in hypertensive type II diabetic males on sulfonylurea treatment

OBJECTIVES

To study the effects on blood pressure and glucose homeostasis of felodipine, a calcium antagonist.

DESIGN

A double-blind randomized cross-over study comparing felodipine ER and placebo.

SETTING

A university centre of diabetic care in Malmö, Sweden.

SUBJECTS

Seventeen hypertensive type II diabetic males on oral sulfonylurea (glibenclamide) treatment.

INTERVENTIONS

Four-week treatment periods separated by a 2-week wash-out period. Felodipine 10-20 mg once daily was given.

MAIN OUTCOME MEASURES

Blood pressure, heart rate, HbA1c and response to oral glucose tolerance test; glucose, insulin and c-peptide. Measured before randomization and at the end of each double-blind treatment period.

RESULTS

Blood pressure was significantly reduced during felodipine treatment and heart rate slightly increased. Felodipine did not influence insulin or c-peptide levels. There was no significant change in glucose levels but an increase in HbA1c.

CONCLUSION

The study demonstrated that felodipine is an effective agent for type II diabetic patients on glibenclamide treatment. The effect on HbA1c is noteworthy even if not of clinical significance in the short term. Controlled long-term studies in diabetic patients are needed to fully evaluate antihypertensive agents.

Metabolic effects of isradipine as monotherapy or in combination with pindolol during long-term antihypertensive treatment

OBJECTIVES

To evaluate the effects of isradipine alone and in combination with pindolol on glucose and lipid metabolism during long-term antihypertensive therapy.

DESIGN

Open long-term study with parallel groups.

SETTING

Kungsgärdet Geriatric Hospital, Uppsala, a tertiary referral hospital.

SUBJECTS

Twenty-six untreated hypertensive subjects.

INTERVENTIONS

After 4 weeks on placebo, isradipine was titrated up to 10 mg daily to achieve appropriate blood pressure control (n = 11). If this failed, 5-10 mg pindolol was added. The treatments were continued for 2 years.

MAIN OUTCOME MEASURES

Blood pressure, lipoprotein measurements, intravenous glucose tolerance test, hyperinsulinaemic euglycaemic clamp, HbA1c, body weight.

RESULTS

Treatment with isradipine alone caused a sustained reduction in blood pressure (-22/-10 mm Hg, P < 0.01), but an increase in body weight (+2.2 kg, P < 0.05) and HbA1c (+1.5%; P < 0.001) were also noted. Addition of pindolol resulted in a similar degree of blood pressure reduction and weight gain, whilst HbA1c was less affected (+1.0%; P < 0.05, compared to isradipine alone). Insulin sensitivity became impaired in both groups (-1.2 to -1.5 mg kg-1 min-1; P < 0.01 for M-value at hyperinsulinaemic clamp) but after adjustment for the change in body weight the impairment was only significant (P < 0.01) in the group with combined treatment. The combined treatment also resulted in an increase in very-low-density-lipoprotein (VLDL) triglycerides (+ 0.37 mmol L-1; P < 0.05).

CONCLUSIONS

The hypotensive effect of isradipine was sustained during long-term use but was associated with weight gain and an impaired glucose control. When isradipine was combined with pindolol there was also a reduction in insulin sensitivity and an increase in VLDL triglycerides, possibly as effects of the beta-adrenergic blockade.

Improved separation of acetaldehyde-induced hemoglobin

A fast-eluting minor variant of hemoglobin A, designated as HbA1-AcH, appears elevated after the incubation of red blood cell hemolysates with acetaldehyde (AcH) and has been proposed as a diagnostic marker for alcoholism or as an indicator for heavy drinking. We have developed an improved HPLC separation of this peak and others elevated by AcH using a polyaspartic acid column (PolyCAT A, PolyLC, Inc.) and a nonlinear buffer gradient with pH changes from 6.6 to 6.8. Saline-washed red blood cells were treated with sodium acetate buffer (pH 5.5) to remove unstable Schiff bases, and then hemolyzed by addition of an equal volume of H2O and 0.4 volumes of CCI4. HbA1-AcH and several others, including two peaks in the HbA1a+b cluster, Hb Pre-A1c, and HbA1d3 were significantly increased by AcH incubation, and the changes were only partially reversible with time. Improved resolution of these peaks allows more accurate quantitation of AcH adducts of hemoglobin.

Production of antibodies that recognize the heterogeneity of immunoreactive sites in human hemoglobin chemically modified by acetaldehyde

Human hemoglobin (Hgb) was incubated with acetaldehyde under two different conditions: (a) in the presence of 250 mM acetaldehyde for 1 hr then reduced with 100 mM NaCNBH3 for an additional 4 hr at room temperature; and (b) in the presence of 500 mM acetaldehyde for 10 days at room temperature and then reduced with 1 mM NaBH4 for 1 hr. It was found that 44% and 27% of free amino groups in Hgb-acetaldehyde adduct (AA) remained unmodified when Hgb was treated under conditions (a) and (b), respectively. SDS-PAGE analysis revealed that the molecular weight of Hgb-AA(a) [Hgb modified under condition (a)] was slightly greater than that of unmodified Hgb and extensive protein cross-linking had occurred in Hgb-AA(b) [Hgb modified under condition (b)]. Electrophoresis on agarose gel showed the order of negative charge was Hgb-AA(b) > Hgb-AA(a) > unmodified Hgb. Polyclonal antibody raised in rabbits using keyhole limpet hemocyanin as the carrier protein modified by acetaldehyde under condition (a) [i.e., KLH-AA(a)] preferentially recognized Hgb-AA(a), whereas antibody raised using KLH-AA(b) as the immunogen recognized only Hgb-AA(b). In conclusion, antibodies raised with protein-AA antigens produced under different conditions recognize different epitopes.

A mutagenic study of the allosteric linkage of His(HC3)146 beta in haemoglobin

We have examined the contribution of His(HC3)146 beta to the alkaline Bohr effect of human haemoglobin (HbA) by replacing it with Gln, using site-directed mutagenesis, and studying the structural and functional consequences. Oxygen equilibrium curves of the mutant show that the effect of pH on the oxygen affinity, the alkaline Bohr effect, is half that of HbA in the presence of chloride ion and less than 10% in its absence. Crystallographic analysis shows that the mutation introduced only small structural changes localized to the site of substitution, proving that the replacement of the hydrogen bond between the ionizable side-chain of His146 beta and Asp94 beta by a hydrogen bond between the unionizable side-chain of Gln146 beta and the same aspartate is solely responsible for the reduction of the alkaline Bohr effect. Our data confirm that His(HC3)146 beta is predominantly responsible for the chloride-independent component of the alkaline Bohr effect which results from the breaking of the hydrogen bond between His(HC3)146 beta and Asp(FG1)94 beta accompanying the transition from the quaternary deoxy to oxy-structure.

Preparation of unaltered hemoglobin from human placentas for possible use in blood substitutes

Hemoglobin extracted from human placentas could be used as the basis of blood substitutes provided it could be prepared on a large scale with appropriate oxygen-binding properties. Unfortunately, the industrial conditions under which it is extracted, produce hemoglobin with high oxygen affinity and which is no longer influenced by the classical effectors. These characteristics were shown to be caused by a degradation of the alpha-chain brought about by an arginine carboxypeptidase present in the placental tissues and leading to the disappearance of the C-terminal arginine residue. This carboxypeptidase which is released from the tissues during the process of crushing the frozen placentas, degrades the protein during the chromatographic purification procedure. The addition of an inhibitor of this carboxypeptidase (for example, arginine) as soon as the placentas are thawed and during the chromatographic process, makes it possible to obtain placental hemoglobin with oxygen-binding properties quite similar to those of HbA prepared from peripheral venous blood.

Hydrogen peroxide modification of human oxyhemoglobin

The effect of H2O2 on the primary structure of OxyHb was studied. Upon treatment of OxyHb with H2O2 ([Heme]/[H2O2] = 1), tryptophan and methionine residues of the beta-chain were modified. Treatment of ApoHb with H2O2 resulted in the modification of histidine and methionine residues in both globin chains. Tryptophan residues were unaffected. Modification of methionine residues in both the beta-chain of OxyHb and ApoHb probably results from the direct oxidation of methionine by H2O2. The modification of histidine residues in ApoHb may be mediated by a metal-catalyzed oxidation system comprised of H2O2 and histidine-bound iron. The H2O2-mediated modification of tryptophan in the OxyHb beta-chain, however, requires the heme moiety.

Equilibrium oxygen binding to human hemoglobin cross-linked between the alpha chains by bis(3,5-dibromosalicyl) fumarate

Oxygen equilibrium curves of human hemoglobin Ao (HbAo) and human hemoglobin cross-linked between the alpha chains (alpha alpha Hb) by bis(3,5-dibromosalicyl) fumarate were measured as a function of pH and chloride or organic phosphate concentration. Compared to HbAo, the oxygen affinity of alpha alpha Hb was lower, cooperativity was maintained, although slightly reduced, and all heterotropic effects were diminished. The major effect of alpha alpha-cross-linking appears to be a reduction of the oxygen affinity of R-state hemoglobin under all conditions. However, while the oxygen affinity of T-state alpha alpha Hb was slightly reduced at physiologic chloride concentration and in the absence of organic phosphates, KT was the same for both hemoglobins in the presence of 2,3-diphosphoglycerate (or high salt) and higher for alpha alpha Hb in the presence of inositol hexaphosphate. The reduced O2 affinity arises from smaller binding constants for both T- and R-state alpha alpha Hb rather than through stabilization of the low affinity conformation. All four Adair constants could be determined for alpha alpha Hb under most conditions, but a3 could not be resolved for HbAo without constraining a4, suggesting that the cross-link stabilizes triply ligated intermediates of hemoglobin.

Influence of ligation state and concentration of hemoglobin A on its cross-linking by glycolaldehyde: functional properties of cross-linked, carboxymethylated hemoglobin

The ligation state of hemoglobin during its cross-linking by glycolaldehyde influences the ultimate oxygen affinity of the cross-linked protein. Thus, if the cross-linking is performed with carbonmonoxy-hemoglobin, the oxygen affinity increases slightly to a P50 of 7 mmHg from a P50 of 9 mmHg for unmodified hemoglobin. In contrast, when deoxyhemoglobin is cross-linked with glycolaldehyde, the oxygen affinity of the product decreases (P50 = 15 mmHg). When deoxyhemoglobin is first carboxymethylated and then cross-linked with glycolaldehyde, an even lower oxygen affinity is achieved (P50 = 23 mmHg). Carboxymethylated hemoglobin is very responsive to the presence of 5% CO2 with a P50 of 33 mmHg, which is lowered further to 42 mmHg when chloride (0.1 M) is also present. Hemoglobin carboxymethylated and cross-linked under anaerobic conditions is also responsive to the modulators CO2 and chloride with a resultant oxygen affinity of 27 mmHg. The type of cross-linking of liganded hemoglobin by the mild reagent glycolaldehyde is dependent upon the initial hemoglobin concentration. Thus, with dilute hemoglobin (45 microM in tetramer), cross-linking by glycolaldehyde (50 mM) results in about 75% of 64,000 molecular weight species (some of which are cross-linked within tetramer) and 25% of intertetrameric cross-linked species with a range of molecular weights averaging 128,000-512,000. With hemoglobin solutions of higher concentration (360 microM), the amount of the higher molecular weight species increases to about 65% with a corresponding reduction to 35% in the 64,000 molecular weight component.

The effect of 2,3-diphosphoglycerate on the tetramer-dimer equilibrium of carbon monoxide hemoglobin in dilute solution. Correlation between sedimentation and kinetic behavior

The effect of 2,3-diphospho-D-glycerate on the sedimentation coefficient of carbon monoxide hemoglobin was correlated with the fraction of rapidly reacting hemoglobin observed subsequent to flash photolysis at 23 degrees C at pH 7.30 in buffers of 0.1 M ionic strength. Concentrations of the organic phosphate up to about 5 mM resulted in an increase in S20,w, consistent with an increase in the fraction of tetrameric hemoglobin. A decrease in rapidly reacting hemoglobin parallelled the increase in the sedimentation coefficient. Between 5 and 20 mM 2,3-diphosphoglycerate, S20,w decreased, suggesting that dissociation to dimers was enhanced. An increase in rapidly reacting hemoglobin was also observed in this concentration range. Similar sedimentation results were obtained with oxyhemoglobin at pH 7.00 and carbon monoxide hemoglobin at pH 7.06. Assuming single binding sites on each species, the dissociation constants for 2,3-diphosphoglycerate binding to tetrameric and dimeric HbCO are 0.2-0.3 mM and 2-5 mM at pH 7.30. This biphasic effect of this physiologically important organic phosphate on the state of aggregation of R state hemoglobin has not been previously reported, but it is similar to that previously noted with inositol hexaphosphate, which enhanced tetramer formation at low concentrations, while at higher concentrations it promoted hemoglobin dissociation to dimers (White, S. L. (1976) J. Biol. Chem. 251, 4763-4769; Gray, R. D. (1980) J. Biol. Chem. 255, 1812-1818).

Oxygen-organophosphate linkage in hemoglobin A. The double hump effect

At low concentrations of chloride ions, and in the presence of nonsaturating concentrations of organophosphates, the oxygen equilibrium curves (OEC) for solutions of human adult hemoglobin exhibit a biphasic shape conveniently revealed by graphical analysis of the first derivative of the Hill equation with a characteristic form that we call "the double hump effect." This shape, observed for sub-saturating concentrations of organophosphates, stands in marked contrast to the simple lateral shifts of the OEC represented largely by scaling factors when pH or chloride are varied. In the case of protons or chloride, there is a self-buffering effect due to the presence of a large reservoir of proton or chloride binding sites not necessarily linked to oxygen, whereas such sites do not exist in the case of organophosphates. In addition, in the former case, we are dealing with curves measured at constant activity of the effector, while in the latter, at constant concentration. In the presence of saturating concentrations of inositol hexaphosphate (IHP), at low chloride concentration, the entire OEC is shifted to the right, including both its upper and lower asymptotes, indicating a decrease in the intrinsic oxygen affinities of both the T and R states. Theoretical considerations leading to a successful modeling of OEC obtained under nonsaturating and saturating concentrations of IHP required an expanded two-state allosteric model in which IHP-dependent variations in oxygen association constants for both the T and R conformations are taken into account.