The role of iron status markers in predicting response to intravenous iron in haemodialysis patients on maintenance erythropoietin

BACKGROUND

Iron deficiency (ID) is the main cause of hyporesponsiveness to erythropoietin in haemodialysis patients and its detection is of value since it is easily corrected by intravenous iron. Markers of iron supply to the erythron, including erythrocyte zinc protoporphyrin (Er-ZPP), percentage of hypochromic erythrocytes (Hypo), reticulocyte haemoglobin content (CHr) and soluble transferrin receptor (sTfR), may be more accurate predictors of ID than ferritin (Fer) and transferrin saturation (TSat), but relative diagnostic power and best threshold values are not yet established.

METHODS

In 125 haemodialysis patients on maintenance erythropoietin, the diagnostic power of the above parameters was evaluated by ROC curve, multivariate regression, and stepwise discriminant analyses. Diagnosis of ID was based on haemoglobin response to intravenous iron (992 mg as sodium ferric gluconate complex over an 8-week period).

RESULTS

Fifty-one patients were considered iron deficient (haemoglobin increase by 1.9+/-0.5 g/dl) and 74 as iron replete (haemoglobin increase by 0.4+/-0.3 g/dl). ROC curve analysis showed that all tests had discriminative ability with the following hierarchy: Hypo (area under curve W=0.930, efficiency 89.6% at cut-off >6%), CHr (W=0.798, efficiency 78.4% at cut-off < or =29 pg), sTfR (W=0.783, efficiency 72.4% at cut-off >1.5 mg/l), Er-ZPP (W=0.773, efficiency 73.0% at cut-off >52 micromol/mol haem), TSat (W=0.758, efficiency 70.4% at cut-off <19%) and ferritin (W=0.633, efficiency 64.0% at cut-off <50 ng/ml). Stepwise discriminant analysis identified Hypo as the only variable with independent diagnostic value, able to classify 87.2% of patients correctly. Additional tests did not substantially improve diagnostic efficiency of Hypo >6% alone.

CONCLUSIONS

In haemodialysis patients on maintenance erythropoietin, Hypo >6% is the best currently available marker to identify those who will improve their response after intravenous iron. Cost-effectiveness suggests that this parameter should be a first-line tool to monitor iron requirements in clinical practice.

Microdialysis in Parkinsonian patient basal ganglia: acute apomorphine-induced clinical and electrophysiological effects not paralleled by changes in the release of neuroactive amino acids

During stereotaxic neurosurgery for deep brain stimulation in Parkinson's disease (PD), we performed a microdialysis study of the extracellular amino acid (aspartate, glutamate, glycine, and GABA) concentrations. Their levels were measured in the GPe/GPi of five and in the STN of four different PD patients, after prolonged therapy washout. The results show stable values of basal release of the examined amino acids within 1 h. The basal levels of GABA in "OFF" state were significantly higher in the GPi than in the GPe. Acute apomorphine administration, while inducing clinical amelioration and electrophysiological changes in the examined nuclei, did not change amino acid concentrations. This result could be related to a limited microdialysis ability to detect subtle changes in amino acid spontaneous release. Alternatively, it could suggest that dopaminergic receptors located in the output nuclei, possibly present also in humans, might mediate the acute apomorphine clinical effects, not involving amino acid changes along the direct and/or indirect pathway.

Clinical and electrophysiological effects of apomorphine in Parkinson's disease patients are not paralleled by amino acid release changes: a microdialysis study

We performed a microdialysis investigation of extracellular amino acid (glutamate and GABA) concentrations during sterotaxic neurosurgery (the implantation of permanent electrodes in the internal globus pallidus (GPi) or subthalamic nucleus (STN) for deep brain stimulation in advanced Parkinson's disease (PD) patients, after prolonged therapy wash-out). Electrophysiological single unit recordings and perioperative clinical status assessments were also performed. Amino acid levels were measured in the GPi and GPe (external globus pallidus) of three PD patients and in the STN of another three PD patients. Stable basal release values of the examined amino acids were obtained within one hour. In clinical "off" state, the basal levels of GABA in the GPi were double those in the GPe in all the three patients. This finding could represent a biochemical marker for GPi target identification in PD surgery. Acute subcutaneous apomorphine administration induced electrophysiological changes and clinical amelioration but did not change amino acid concentrations. This result could be due to methodological limitations of the microdialysis technique. Alternatively, it could suggest that the clinical effects of acute apomorphine might also be mediated by direct activation of dopaminergic receptors located in the output nuclei.

Sumatriptan overuse in episodic cluster headache: lack of adverse events, rebound syndromes, drug dependence and tachyphylaxis

This observational study was designed to examine the pattern of sumatriptan use in patients with cluster headache using more than the recommended daily dose of subcutaneously injected (s.c.) sumatriptan. Thirteen patients suffering from episodic cluster headache were asked to record the characteristics of their attacks and drug intake for 1 year. All reported a high daily frequency of attacks (more than 3 per day) and the related overuse of s.c. sumatriptan. The results show that the overall incidence of adverse events among patients receiving sumatriptan injections for the treatment of cluster headache is low. The extended administration of this drug in episodic cluster headache did not result in tolerance problems or tachyphylaxis. Only 4 patients experienced minor adverse events and recovered more slowly than the others. They suffered from migraine without aura and cluster headache, and showed a family history of migraine. Even though they must be viewed with caution, due to the observational nature of the study and the low number of patients included, these results suggest that the profile of sumatriptan may differ in cluster headache compared with migraine.

Simultaneous occurrence of ipsilateral cluster headache and chronic paroxysmal hemicrania: a case report

A 42-year-old man came to our headache unit in October 1995 complaining of recurrent attacks of headache, which had begun in February 1991. Chronic cluster headache was diagnosed, and he was given verapamil, 360 mg per day. The attacks ceased in the following months and verapamil was stopped in March 1996. In May 1997, a recurrence of the attacks required the readministration of verapamil, 360 mg per day. The attacks decreased (one to three per week), but after 2 months the patient reported a worsening in his condition due to the appearance of shorter attacks, which were diagnosed as chronic paroxysmal hemicrania. The administration of indomethacin, 225 mg per day, resulted in the disappearance of the short attacks. The concomitant occurrence of attacks of cluster headache and chronic paroxysmal hemicrania suggests the presence of shared factors in the pathophysiology of the two forms of headache. This hypothesis is supported by previous reports in the literature.

The effect of deep brain stimulation on the frontal N30 component of somatosensory evoked potentials in advanced Parkinson's disease patients

OBJECTIVES

In the present study we investigated whether in advanced Parkinson's disease (PD) patients the frontal component of short somatosensory evoked potentials (SEPs) to median nerve stimulation may be modified by basal ganglia deep brain stimulation (DBS).

METHODS

We recorded the SEPs in 6 PD patients undergoing bilateral functional neurosurgery in the internal globus pallidus (GPi) (4 patients) and in the nucleus subthalamicus (STN) (two patients) during ineffective and effective bilateral BDS. Pre-operatively, the SEPs were also recorded in off therapy and during apomorphine infusion.

RESULTS

From the evaluation of the latency and the amplitude characteristics of the major parietal (N20 and P25) and frontal (N30) components, we observed that whereas the parietal waves did not vary in any condition, the N30 potential showed a remarkable amplitude increase during apomorphine as well as during effective bilateral GPi or STN DBS. Furthermore, after the stimulators were turned off we noticed that the N30 amplitude potential progressively faded almost in parallel with the attenuation of DBS clinical effects.

CONCLUSIONS

Our results lead to the conclusion that the bilateral DBS of both GPi and STN is really effective in producing a selective increase of frontal N30 amplitude probably improving the supplementary motor area functional activity, but these results do not clarify whether this amelioration is due to a central or a 'long loop' mechanism.

Lipoprotein(a) concentration is not associated with venous thromboembolism in a case control study

BACKGROUND AND OBJECTIVE

Lipoprotein(a) is an LDL-like particle displaying strong athero-thrombotic properties. Although Lp(a) plays a pivotal role in the genesis and progression of thrombosis in the arterial district, its role in promoting thrombosis in the venous district is still unclear.

DESIGN AND METHODS

To give further insight into the thrombotic potential of Lp(a), 100 potentially eligible consecutive outpatients who had suffered from previous episodes of venous thrombosis (deep vein thrombosis with or without pulmonary embolism) were enrolled into the study. Thirty-six of these patients who did not fulfil the entry criteria were then excluded from the study. The concentration of Lp(a) was thus measured in 64 patients, and compared to that of 64 control subjects, matched for sex (p=0.46), age (p=0.25) and pharmacological treatment; no subject belonging to the control group had a familial or personal history of venous thromboembolism. Exclusion criteria for both groups included: diabetes mellitus, liver or kidney diseases and malignancy, as established by both laboratory analysis and physical examination. To rule out false elevations of Lp(a) due to the presence of a concurrent acute phase response, C reactive protein (CRP) was measured in both groups using a commercial immunonephelometric assay.

RESULTS

No statistically significant differences were observed in the median Lp(a) concentration between patients and controls (median: 69 vs 83 mg/L, respectively; p=0.34). Neither were any significant differences found between patients who had suffered from deep venous thrombosis with (n=18) or without (n=46) pulmonary embolism (median: 73 vs 69 mg/L, respectively; p=0. 83). The concentration of CRP did not differ significantly between cases and controls (median: 1.8 vs 2.3 g/L, respectively; p=0.37).

INTERPRETATION AND CONCLUSIONS

Although there are several plausible biological mechanisms to explain the strong thrombogenicity of Lp(a) in vitro, we failed to demonstrate a convincing association between Lp(a) and thrombosis in the venous district. Besides the proven prothrombotic role of Lp(a) in some selected clinical settings, it is thus conceivable that the contribution of Lp(a) to genesis and progression of the venous thrombosis might be marginal or efficiently counterbalanced in vivo. The clinical usefulness of including the measurement of Lp(a) among the screening tests for thrombophilic patients, therefore, remains questionable.

Increased serum levels of N-telopeptides (NTx) of bone collagen in postmenopausal Nigerian women

Serum levels of cross-linked N-telopeptides (NTx) of bone collagen, alkaline phosphatase (ALP), and intact parathyroid hormone (PTH) were determined in 64 premenopausal (PRM) and 86 postmenopausal (PSM) women living in northern Nigeria. Serum NTx values were correlated with ALP activity (r = 0.31-0.58, P < 0.01) and PTH (0. 32-0.35, P < 0.01)) in all of the subjects studied, and were also related to age (-0.47, P < 0.001) and body mass index (-0.45, P < 0. 001) in PRM women. Menopause had the effect of increasing the circulating concentrations of NTx and ALP activity by 15% (P = 0. 001) and 11% (P = 0.02), respectively; however, serum levels of PTH were not different between these two groups of women. Compared with Caucasian counterparts matched for age and body mass index, PSM Nigerian women had significantly increased circulating concentrations of NTx (21.7 versus 16.2 nmol BCE/liter, P = 0.01) and demonstrated a trend towards higher ALP activities and PTH levels. These results indicate that (1) discrete reference intervals should be defined for biochemical markers of bone metabolism in African populations, (2) Nigerian women have relatively higher rates of bone turnover, and (3) further investigation of the implications of increased serum NTx should be undertaken using physical methods such as dual X-ray absorptiometry (DXA) and bone ultrasound attenuation.

Effects of hypocaloric dietary treatment enriched in oleic acid on LDL and HDL subclass distribution in mildly obese women

OBJECTIVE

To study the effects of a carbohydrate-enriched (HiCarbo) or olive-oil-enriched (HiMUFA) hypocaloric diet on plasma lipoprotein levels and physical properties.

DESIGN

A six-month follow-up dietary intervention study with a HiCarbo diet providing 60% of total calories as complex carbohydrates, 15% as proteins and 25% as fats [10% saturated (SFA); 7% monounsaturated (MUFA); 8% polyunsaturated fatty acids (PUFA)]; or a HiMUFA diet with 40% complex carbohydrates, 15% proteins and 45% fats (10% SFA; 27% MUFA; 8% PUFA).

SUBJECTS

Twenty consecutive, mildly obese, normolipidemic premenopausal women (11 on HiCarbo and nine on HiMUFA diets) and 14 age- and sex-matched, lean controls.

MEASUREMENTS

Body mass index (BMI), waist/hip ratio, plasma lipoproteins, apolipoprotein (apo) AI and B, LDL and HDL density distribution, and phospholipid fatty acid composition at baseline, and after 3 and 6 months on dietary treatment.

RESULTS

Body weight progressively decreased during the first 3 months and then it stabilized during the following 3 months (-11% vs. baseline in both groups; P < 0.01). LDL-Cholesterol decreased significantly in both groups. HDL-Cholesterol increased significantly in the HiMUFA group, whereas a decreased level was observed in the HiCarbo group. At baseline the obese women had higher very low density lipoprotein (VLDL) and dense LDL-Cholesterol, and lower HDL2 cholesterol levels than the controls; these abnormalities persisted in the HiCarbo diet, whilst a significant decrease in the dense LDL associated with an increase in the HDL2 cholesterol was seen in the HiMUFA diet. HDL3 was not affected by either diet. The LDL/HDL-Cholesterol ratio was not affected by the HiCarbo diet, whilst it was significantly reduced after 6 months of HiMUFA diet as compared with baseline. Apo AI increased in the HiMUFA group, and decreased in the HiCarbo group.

CONCLUSIONS

Both diets were effective in decreasing body weight. At steady weight conditions, only the HiMUFA diet improved LDL and HDL subclass distribution abnormalities present in mildly obese normolipidemic women.

Flow cytometric analysis of intracellular chemokines in chondrocytes in vivo: constitutive expression and enhancement in osteoarthritis and rheumatoid arthritis

Chemokines play a key role in modulating leukocyte functions at sites of inflammation. To assess chondrocyte contribution to the chemotactic environment of inflamed joints the intracellular content of CC and CXC chemokines was investigated. IL-8, GROalpha, MCP-1, RANTES, MIP-1alpha and MIP-1beta expression was evaluated by flow cytometric analysis and RT-PCR in chondrocytes isolated from cartilage specimens obtained from patients with osteoarthritis and rheumatoid arthritis and multiorgan donors as normal controls. All the chemokines except RANTES were found in normal chondrocytes, with different degrees of staining intensity. In osteoarthritis and rheumatoid arthritis patients, an enhancement of IL-8, GROalpha, MIP-1alpha and MIP-1beta was observed.

Electrophysiological and clinical desensitization to apomorphine administration in parkinsonian patients undergoing stereotaxic neurosurgery

A decreased motor response after repeated doses of apomorphine is observed in severely affected Parkinson's disease patients. We simultaneously studied clinical symptoms and internal pallidus single unit activity in three parkinsonian patients underlying stereotaxic neurosurgery for deep brain stimulation. In each patient, two closely spaced doses of intraoperatory apomorphine were administered, while recording the same extracellular unit. The reduced clinical effect of the second administration was correlated to a lessened inhibition of the pallidal single unit recorded throughout the double administration. Our data support the proposition that fast postsynaptic desensitization to dopamine agonists may take place in the basal ganglia nuclei and play a role in the physiopathology of levodopa long-term treatment syndrome.

Reduced susceptibility to oxidation of low-density lipoprotein in patients with overproduction of nitric oxide (Bartter's and Gitelman's syndrome)

BACKGROUND

The oxidation of low-density lipoprotein (LDL) might play an important role in the development of atherosclerosis.

OBJECTIVE

To establish whether greater than normal production of nitric oxide (NO) in vivo protects LDL from oxidation.

PATIENTS AND METHODS

We studied nine subjects affected by Bartter's and Gitelman's syndrome (both characterized by greater than normal production of NO), and 10 subjects matched for age, sex and lipid levels as controls. LDL particles were isolated from plasma by density gradient ultracentrifugation. Susceptibility of LDL to oxidation was evaluated after incubation with copper sulfate solution, by measuring the formation of conjugated dienes, the thiobarbituric acid-reactive substances, and the volatile peroxidation products of n-3 (propanal) and n-6 (pentanal and hexanal) polyunsaturated fatty acids. Phospholipid fatty acid composition of LDL was determined by gas chromatography. LDL alpha-tocopherol concentrations were measured.

RESULTS

Patients with Bartter's and Gitelman's syndrome had LDL particles smaller and/or denser than those of controls [Rf = 0.38 +/- 0.03 versus 0.42 +/- 0.02 (mean +/- SD), P < 0.01], which hence were assumed to be more oxidizable. The phospholipid fatty acid composition of LDL and the alpha-tocopherol concentrations did not significantly differ between patients and controls. The duration of the lag phase, which is the time preceding formation of conjugated dienes, did not differ between groups, but the lag phase times were related to urinary excretion of nitrite/nitrate from patients (r = 0.66, P < 0.05). Moreover, patient LDL had produced less thiobarbituric acid-reactive substances after 5 h (P < 0.04), and less pentanal and hexanal after 5 and 6 h (P < 0.04 and P < 0.02, respectively) than had that of controls.

CONCLUSIONS

Greater than normal production of NO in vivo is associated with lower than normal susceptibility of LDL to oxidation in vitro, suggesting that NO plays a protective role in the development of atherosclerosis.

Cytokines and migraine: increase of IL-5 and IL-4 plasma levels

Thirty-two patients suffering from migraine without aura were assessed during in interictal period to evaluate the contribution of cytokines to the pathophysiology of migraine. To this end, plasma levels of IFN-gamma, IL-4, IL-5, and IL-10 were measured by enzyme-linked immunosorbent assay (ELISA) techniques. Plasma levels of both IFN-gamma and IL-10 were not increased in the patients and did not differ significantly from healthy controls. Of interest, we observed a strong increase of IL-5 levels in 84.3% as well as increased IL-4 levels in 37.5% of patients with migraine without aura. These results suggests a preferential enhancement of some Th2-type cytokines, and may support the growing arguments of an immunoallergic mechanism in the pathophysiology of migraine.

Patient education and migraine: a pilot study

Our study examines the effectiveness of an educational approach to migraine patients. A course in migraine education was set up for 30 patients suffering from this disease; meetings were structured taking into consideration specific educational aims, with parameters evaluated before the course, at the end of the course and at a 3-month follow-up. The results, particularly the increase in the migraineurs' knowledge of their disease and the decrease in the use of symptomatic drugs, suggest the effectiveness of the course. Furthermore, our study suggests that there is a need to build educational processes into therapeutic protocols, as they enable patients to manage their chronic diseases more correctly.

Does pattern electroretinogram spatial tuning alteration in Parkinson's disease depend on motor disturbances or retinal dopaminergic loss?

Systemic decrease of dopaminergic cells, such as in Parkinson's disease may produce visual alterations in humans. In order to show possible pattern electroretinogram (PERG) spatial tuning function (STF) alterations due to impaired dopaminergic transmission in humans, we studied a group of Parkinson's disease patients before and during treatment with the dopamine precursor, levodopa, and compared their performances with those of an age-matched control group. Moreover, in order to exclude the possible involvement of motor disabilities to produce PERG alterations, we also investigated PERG responses in post-traumatic parkinsonian patients who exhibited motor abnormalities as a consequence of focal lesions of basal ganglia, in the absence of systemic dopaminergic degeneration. Our results showed a clear decrease of PERG responses in Parkinson's disease patients particularly at medium spatial frequency range (2.7-4.0 cycles/degree) with a substantial preservation of responses at low frequencies. Levodopa therapy reversed these alterations in Parkinson's disease patients, resulting in the recovery of a normal tuning function shape. In contrast to Parkinson's disease, the tuning function appeared to be preserved in post-traumatic parkinsonian patients. Our results clearly establish a relationship between retinal alteration in PD patients and dopaminergic retinal function.

Effects of increasing doses of apomorphine during stereotaxic neurosurgery in Parkinson's disease: clinical score and internal globus pallidus activity. Short communication

We analysed the firing activity of internal globus pallidus cells in two Parkinson's disease patients undergoing stereotaxic surgery. Both patients showed an advanced rigid-akinetic syndrome with disabling levodopa induced dyskinesias. Apomorphine, intraoperatively administered at doses (1-2 mg) inducing a short but clear clinical improvement without involuntary movements, reduced the pallidal discharge rate by > 50% in both patients. An higher apomorphine dose (2.5 mg), tested in one hemisphere, blocked the firing activity with a time course independent from the occurrence of dyskinesias. These finding suggest that the reduction of internal pallidus excitability is one of the mechanisms underlying the efficacy of dopaminergic therapy, but also that changes in other basal ganglia stations are likely to be involved in dyskinesias.

Autotransfusion in major orthopaedic surgery: experience with 1785 patients

Using a prospective audit, we have evaluated the efficacy of an integrated autotransfusion regimen which comprised predepositing and intra- and postoperative blood salvage in major orthopaedic surgery. We examined prospectively the records of 1785 patients (1198 females, 5867 males, mean age 62 (range 16-90) yr, preoperative haemoglobin concentration 13.4 (SD 1.4) g dl-1) undergoing total hip arthroplasty (THA, 1229 patients), THA after removal of internal fixation devices (RFD + THA, 18 patients), total knee arthroplasty (TKA, 263 patients), revision surgery of the hip (HR cup + stem revision, 197 patients; cup revision, 53 patients; stem revision, 16 patients) and total knee revision (TKR, nine patients). We estimated that the number of predonations (MSBOS = maximum surgery blood order schedule) was 2 u. for THA, TKA and TKR, and 3 u. for partial or total hip revision and total hip arthroplasty with fixation removal. We found that it was possible to obtain the MSBOS in 1597 patients (89.5%). Homologous red blood cell (HRBC) transfusions were carried out in 131 patients (7.3%). We found that the need to use HRBC was significantly associated with failure to meet the number of MSBOS, female sex, lower preoperative haemoglobin concentration, use of calcium heparin for antithrombosis prophylaxis, more extensive surgery, higher ASA rating and co-existing diseases such as coronary artery disease.

Migraine with and without aura in the same patient: expression of a single clinical entity?

Migraine with aura and migraine without aura may be different clinical expressions of one disease. This theory is debated, however. In order to further address the issue, we administered a standardized questionnaire to 45 migraineurs. The results indicate a significant overlap between migraine with and without aura, most importantly with respect to response to therapy; 70% of patients had similar responses.

Pharmacological evidence that the activation of the Na(+)-Ca2+ exchanger protects C6 glioma cells during chemical hypoxia

1. In C6 glioma cells exposed to chemical hypoxia a massive release of lactate dehydrogenase (LDH) occurred at 3 and 6 h, coupled with an increased number of propidium-iodide positive dead cells. 2. Extracellular Na+ removal, which activates the Na(+)-Ca2+ exchanger as a Na+ efflux pathway and prevents Na+ entrance, significantly reduced LDH release and the number of propidium iodide positive C6 cells. 3. During chemical hypoxia, in the presence of extracellular Na+ ions, a progressive increase of [Ca2+]i occurred; in the absence of extracellular Na+ ions [Ca2+]i was enhanced to a greater extent. 4. The blockade of the Na(+)-Ca2+ exchanger by the amiloride derivative 5-(N-4-chlorobenzyl)-2',4'-dimethylbenzamil (CB-DMB), lanthanum (La3+) and the Ca2+ chelator EGTA, completely reverted the protective effect exerted by the removal of Na+ ions on C6 glioma cells exposed to chemical hypoxia. 5. The inhibition of the Na(+)-Ca2+ antiporter enhanced chemical hypoxia-induced LDH release when C6 glioma cells were incubated in the presence of physiological concentrations of extracellular Na+ ions (145 mM), suggesting that the blockade of the Na(+)-Ca2+ antiporter during chemical hypoxia can lead to increased cell damage. 6. Collectively, these results suggest that activation of the Na(+)-Ca2+ exchanger protects C6 glioma cells exposed to chemical hypoxia, whereas its pharmacological blockade can exacerbate cellular injury.