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Biomedical subjects

A F Remacha

Publications and source records attributed to A F Remacha.

31 records · Page 2Linked to original sources
PubMed1996

Changes in reticulocyte fractions during peripheral stem cell harvesting: role in monitoring stem cell collection.

We prospectively evaluated the changes in immature reticulocyte fractions during peripheral blood stem cell mobilization to determine any possible relationship with mobilization of stem cells into the peripheral blood. Circulating neutrophils, immature reticulocyte fractions (% of HFR + MFR) (HMFR) (measured by flow cytometry), circulating CD34+ cells (measured by flow cytometry) and CFU-GM (measured by semisolid media assay in the apheresis fluid) were closely monitored following priming with chemotherapy and colony-stimulating factors in 15 patients with hematological or solid tumors (group I). Day 0 was defined as the day on which the neutrophil count fell below 0.5 x 10(9)/l. In a second group of nine patients (group II) reticulocyte fractions and CD34+ cells were measured directly on the days on which they were predicted to increase using the data from group I. Reticulocyte counts and HMFR were also monitored in 18 patients who were mobilized with G-CSF alone. In group I, a significant rise in HMFR and CD34+ cells occurred on days 2, 4 and 6, and a linear correlation between HMFR on day 2 and CD34+ cells on day 4 was demonstrated (P = 0.0068, r = 0.74). In group II similar patterns of recovery were found. During mobilization with G-CSF alone HMFR significantly increased on days 2, 4 and 6 of treatment with respect to baseline values, and a multiplicative relationship between the increase of HMFR and neutrophils was observed (r = 0.707, P < 0.00001). Unfortunately, patients who did not mobilize CD34+ cells (one in groups I and II and three in the G-CSF group) showed similar HMFR kinetics to those who mobilized CD34+ cells. An increase in immature reticulocyte fractions precedes the presence of circulating CD34+ cells by about 2 days in patients mobilized with chemotherapy and growth factors, and it could thus serve as an indirect surrogate marker for monitoring the timing of stem cell harvesting. An unexpected increase of HMFR during treatment with G-CSF alone was found, indicating an effect of this factor on erythropoiesis in vivo.

Adult↗
PubMed1994

Postrenal transplant erythrocytosis: further evidence implicating erythropoietin production by the native kidneys.

True erythrocytosis is a relatively common complication of successful renal transplantation. From a group of 17 patients with post-transplant erythrocytosis (PTE), four underwent selective venous catheterization of the native and transplanted kidneys because of arterial hypertension. In three who presented with active PTE at the time the procedure was performed the peripheral blood (PB) concentration of EPO was elevated, and the level of erythropoietin (EPO) in native kidney veins was significantly higher than the PB and allograft EPO levels. Additionally, only one of the three cases had high levels of plasma renin activity (PRA). The fourth patient showed normal levels of EPO and PRA in PB and in venous blood from the native and transplanted kidneys. However, the PTE had subsided 4 months before the performance of the catheterization after he redeveloped terminal renal failure; the loss of a functioning allograft might have blunted the overproduction of EPO by the native kidneys. In conclusion, in patients with PTE, inappropriate EPO production seems to originate from the diseased native kidneys, and there seems to be no correlation between the production of EPO and the PRA.

Adult↗
PubMed1993

[Hematologic changes induced by exertion during a long-distance race].

PURPOSE: To evaluate the haematological changes induced by a long-distance race in well trained runners. PATIENTS AND METHODS: The haematological changes presented by 17 runners (15 men and 2 women) were assessed in a 6-hour race. For this purpose samples were examined before the race, 2 hours later, 4 hours later, at the end of the race, and 4 days after the trial. RESULTS: Haemoglobin rates, as well as leucocyte, neutrophil, monocyte and platelet counts were increased, probably due to decreased plasma volume. Haemolytic traits were seen as well, namely, increased reticulocyte count and decreased haptoglobin. High transferrin-transport capability and serum B12 levels were also present. Mild haematuria was found without any haemosiderinuria, siderinuria or haemoglobinuria. All these changes recovered in the post-race study. CONCLUSION: Changes in the major haematologic values are present during long-distance races, some of them due to haemoconcentration. Leucocytosis, haemolysis and haematuria are noteworthy, and these findings must be borne in mind when evaluating the health of runners.

Adult↗
PubMed1992

[Influence of chronic renal failure and of its treatment on serum erythropoietin].

BACKGROUND: In order to know the influence of dialysis treatment in erythropoietin production, serum erythropoietin (Ep) has been studied in patients with anemia due to chronic renal failure (CRF). METHODS: Thirty six of them in hemodialysis (HD), 10 in continuous ambulatory peritoneal dialysis (CAPD) and 18 in predialysis stage (PD) and their results were compared to two control groups, including 72 healthy controls (HC) and the second one 89 iron deficiency anemia patients (ID). RESULTS: Patients had lower Hb and Ep levels than the other groups. Although Ep was higher in CAPD and PD. Ep levels were similar to HC values, and lower than ID levels. It could be demonstrated any correlation between Hb and Ep in CRF patients, however a negative exponential correlation was demonstrated in ID patients between Hb and Ep (r = -0.83; p less than 0.00001). In summary, Ep is higher in CAPD and in PD than in HD, but the levels are lower than they should be expected. CONCLUSIONS: These data confirm an Ep production failure in most of IRC patients and it seems likely that Ep treatment could be effective to treat the anemia of CRF.

Anemia↗
PubMed1992

Congenital intrinsic factor deficiency in a Spanish patient.

Vitamin B-12 deficiency was diagnosed in a 26-year-old man. Examinations performed to determine the etiology of the deficiency showed a vitamin B-12 malabsorption in the Schilling test which was corrected by adding intrinsic factor (IF) as well as normal gastric mucosa and acid secretion, although IF in gastric juice was absent. Family study showed normal serum vitamin B-12 levels in the parents, who are first cousins, and siblings. A gastric examination in the father and the sister showed decreased IF secretion, indicating heterozygosity for the disorder.

Adult↗
PubMed1992

Erythroid abnormalities in rheumatoid arthritis: the role of erythropoietin.

Erythroid alterations were studied in 136 patients with rheumatoid arthritis (RA). Anemia was present in 75 cases. A definite diagnosis was determined in 65. The most frequent anemia was that of chronic disease (ACD) (43 cases); 14 patients with ACD presented with moderate to severe anemia. Prevalence of deficiencies were also high (15 cases had iron deficiency anemia, IDA). Serum erythropoietin levels were different in patients with RA compared with a healthy control group (p < 0.00001). Serum erythropoietin was increased in ACD (49 +/- 28.8 U/l) with respect to both RA (38.6 +/- 12.7 U/l, p = 0.0036) and controls (18.2 +/- 7.6 U/l, p < 0.00001). Although hemoglobin (Hb) was similar in ACD and IDA, serum erythropoietin in ACD was lower than in IDA (p = 0.01). There was a negative relationship between Hb and serum erythropoietin in ACD (r = -0.42, p = 0.005). In conclusion, almost 50% of patients with RA have anemia and ACD is the most frequent. As serum erythropoietin in ACD is blunted, patients with moderate to severe ACD are possible candidates for erythropoietin treatment.

Adult↗
PubMed1991

Vitamin B-12 abnormalities in HIV-infected patients.

A prospective study of 60 consecutively admitted patients with HIV infection was performed to document the prevalence, etiology and manifestations of low serum vitamin B-12 in such patients. Low serum B-12 levels were found in 10 patients (16.7%). In 6, vitamin B-12 absorption was impaired and hog intrinsic factor addition did not improve it. Patients with low vitamin B-12 levels showed lower hemoglobin, leukocytes, lymphocytes, CD4 lymphocytes and CD4/CD8 lymphocyte ratio than HIV patients with physiological serum vitamin B-12 levels. However, bone marrow megaloblastosis was found in only 3 low vitamin B-12 patients and the deoxyuridine suppression test was pathological in only 1 case. In 7 patients, parenteral treatment was begun with variable response despite serum vitamin B-12 correction. In conclusion, low serum vitamin B-12 is often found in HIV-infected patients and it could be related to malabsorption, but clear megaloblastic abnormalities and treatment response could not be demonstrated. A decreased concentration of the serum binders due to disturbances in the leukocytes and related immunocompetent cell may play an additional role.

Adult↗
PubMedDate not supplied

Evaluation of erythropoietin in endurance runners.

To evaluate the role of erythropoietin (Epo) in the erythroid abnormalities often found in athletes, Epo was evaluated by radioimmunoassay in endurance runners (ER). In a first study, 46 experienced ER, 11 with iron deficiency (ID group), were studied during a training period. In ID and non-ID runners, serum Epo (SEpo) levels were similar to sedentary controls (ID = 19.1 +/- 4.9 U/L, non-ID = 19.7 +/- 5.5 U/L and controls 19.7 +/- 9.2 U/L). In a second study, serum and urine erythropoietin (UEpo) levels were evaluated in 17 ER during a 6-hour race. Samples were taken before the race (pre-race), immediately following (6-hour) and 4 days after (post-race). No differences were observed in SEpo levels (pre-race = 19.8 +/- 4.1 U/L, 6-hour = 21.2 +/- 4.9 U/L and post-race = 21 +/- 4 U/L), but UEpo increased following the race (pre-race = 15.4 +/- 9.6 U/L, 6-hour = 26.1 +/- 6.2 U/L and post-race = 14.1 +/- 6.5 U/L) (p < 0.0001) and this UEpo increase was related to urine creatinine changes (rs = 0.79, p < 0.00001). In conclusion, SEpo in ER does not differ from sedentary values and does not vary with competition; however, UEpo increases during a long-distance race. These data may be important for a correct evaluation of Epo abusers and sports anemia.

Adult↗
PubMedDate not supplied

Vitamin B12 transport proteins in patients with HIV-1 infection and AIDS.

BACKGROUND: Low vitamin B12 levels (B12) are often observed in patients infected with human immunodeficiency virus type 1 (HIV-1). The causes underlying this finding are thought to be intestinal malabsorption and/or abnormalities in the vitamin plasma binding proteins (BP). MATERIAL AND METHODS: Serum levels of B12 and BP were studied in eighty HIV-1-positive patients, 55 of whom met the diagnostic criteria for AIDS. Subjects were divided into various subgroups: non-AIDS HIV-1 positive versus AIDS; low serum B12 levels (DB12, < 150 pmol/L) versus normal serum B12 levels (NB12); and the results obtained were compared both between groups and with respect to a reference population (RF) of normal volunteers. RESULTS: Low levels of serum B12 were found in 14 patients (17.5%), without differences between the AIDS and non-AIDS subgroups. The levels of holohaptocorrin (holoHP) were lower in the DB12 group than in the NB12 and RF groups (p < 0.01), and no differences were found between the AIDS and non-AIDS groups. The levels of apotranscobalamin (apoTC) were higher in the AIDS group than in the non-AIDs and RF subjects (p < 0.01), but no differences were found between the DB12 and NB12 groups. Likewise, no differences were noted in the levels of holoTC between the DB12 and NB12 groups. A positive correlation between neutrophil counts and free serum haptocorrin levels (apoHP) (rs = 0.36; p = 0.002), and a negative one between the former and the levels of apoTC (rs = -0.3; p = 0.009) were observed. Furthermore, a positive correlation was detected between the erythrocyte sedimentation rate and the levels of apoHP and TC. CONCLUSIONS: Low serum levels of HP in HIV-1 positive patients could lead to the low levels of serum vitamin B12 frequently observed in this patient population, while the high levels of TC could merely represent a non-specific marker of inflammation (acute phase, reactant).

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Serum erythropoietin and erythroid activity in vitamin B12 deficiency.

We studied erythropoiesis in 31 patients with vitamin B12 deficiency by measuring serum erythropoietin (s-Epo), serum transferrin receptor (s-TfR, taken as an index of total erythroid activity), reticulocyte count, and the reticulocyte maturation index (RMI). s-Epo and s-TfR were measured with commercial immunoassays, whereas reticulocyte count and RMI were determined by flow cytometry. s-Epo (123 +/- 196 U/L) and s-TfR (4.1 +/- 2 mg/L) levels were increased in patients with vitamin B12 deficiency. The absolute reticulocyte counts were decreased (29 +/- 18 x 10(9)/L) with a relative increase in the most immature fractions (RMI: 29.6 +/- 18%). A significant negative relationship was found between s-Epo and Hb level (r = -0.65, p < 0.0001). On the average, however, s-Epo was inappropriately low for the degree of anemia, since the observed/predicted (O/P) s-Epo ratio was 0.80 +/- 0.28 in vitamin B12 deficiency vs 1.00 +/- 0.16 in a group of patients with iron deficiency anemia. It is concluded that at least a portion of patients with vitamin B12 deficiency have serum erythropoietin levels that are inappropriately low for the degree of anemia.

Adolescent↗
PubMedDate not supplied

Serum erythropoietin in the diagnosis of polycythemia vera. A follow-up study.

BACKGROUND AND OBJECTIVE: It has been suggested that the determination of serum erythropoietin (sEpo) may be useful in distinguishing between polycythemia vera (PV), relative polycythemia and secondary polycythemia (SP), but no conclusive evidence has yet been provided for this. In the present work, we evaluated the role of sEpo in the differential diagnosis of polycythemia vera and its usefulness in the follow-up of PV patients. METHODS: sEpo was assessed in 190 patients with polycythemia of different etiologies. A follow-up study was carried out in some of these patients (27 with secondary polycythemia and 17 with polycythemia vera). RESULTS: sEpo levels were higher in SP than in PV and relative polycythemia. There were, however, differences with regard to the various etiologies of SP. Polycythemia related to congenital heart disorders showed the highest levels of sEpo of the SP. When a study was conducted, sEpo alone as a diagnostic parameter displayed an efficiency of more than 90% and the most discriminating value was 5 U/L. Using lower levels (below 2 U/L) and higher levels (above 12 U/L), it was possible to distinguish between SP and PV, although an important overlap was detected between these limits (approximately 50% of cases). The follow-up study showed that in half the patients with SP the levels of sEpo were at times < 12 U/L and at other times greater than this value. At least three determinations were necessary to detect an elevated reading. In PV after venesection there was an increase in sEpo in some cases, although most of the time there was no change. INTERPRETATION AND CONCLUSIONS: Using sEpo, it was possible to differentiate between PV and SP, despite an important overlap. A follow-up study demonstrated that the increase in sEpo was intermittent in SP and that in many of these cases more than one determination could be helpful.

Adult↗