Distribution of endogenous and injected porphyrins at the subcellular level in rat hepatocytes and in ascites hepatoma

Different doses (0.5-20 mg/kg) of hematoporphyrin (HP) have been injected intraperitoneally into normal rats and rats affected by Yoshida ascites hepatoma. About 80% of HP reaching the liver was recovered in the extracellular compartment after liver perfusion, the ratio of extra- to intracellular HP being essentially independent of the administered dose. Similar data were obtained at different times after injection of 20 mg/kg HP. Intracellular HP largely accumulates in the mitochondria and in the membrane components of the nuclear fraction of isolated hepatocytes. Kinetic studies suggest that the cell receptors of highest affinity for HP are present in the external membrane. The latter result obtains for ascites hepatoma cells in an even more evident way, although the latter cells exhibit secondary HP binding sites probably constituted by cytoplasmatic proteins. Moreover, the clearance of intracellular HP from malignant cells occurs at a remarkably lower rate as compared with HP clearance from liver cells.

Acute myelogenous leukemia in Down's syndrome: report of a single pediatric institution using a BFM treatment strategy

Between July 1990 and December 1995, 111 new consecutive pediatric patients with acute myelogenous leukemia (AML) have been treated in our institution. Eleven of them (9.9%) had Down's syndrome (DS), 6 boys and 5 girls. The median age was 22.5 (range 10-40) months. FAB subtypes were the following: M7: 6, M4: 3, and M0: 2. Five of them had previously had myelodysplasia and in 3, all FAB M7, myelofibrosis was detected. This population was treated with two consecutive protocols. Nine patients were included in the AML-HPG-90 protocol and 2 patients in the AML-HPG-95 study, respectively. However, all DS patients in this series received the same treatment. Eight patients achieved complete remission: two patients received two cycles of intensification with high dose (HD) ara-C, and 1 patient, only one cycle; the other 5 were prevented from receiving such therapy because of unacceptable toxicity or death. At 45 months, event-free survival and overall survival estimates were 0.30, S.E. 0.16. Mortality was remarkably high. All deaths (7) were associated with sepsis (5) or pulmonary infection (2). Three deaths occurred before achieving complete remission, 3 patients died during the consolidation phase and 1 died whilst off treatment. No one presented leukemic relapse. We conclude that this AML-BFM treatment strategy is highly toxic to children with DS and AML in our setting. Efforts will be made to improve clinical support and to administer less intensive therapy to this particular pediatric AML subgroup, which, in fact, has a better prognosis than the same non-trisomic population.

Ouabain-inhibiting activity of aldosterone antagonists

It has been suggested that endogenous substances (known as ouabain-like factors, OLF), secreted from the central nervous system in response to salt and water retention, inhibit the cell membrane Na+/K+ pump in the renal tubules and reduce sodium reabsorption. However, by also acting upon vascular smooth muscle cells, they may induce cell Na+ and Ca++ accumulation, vasoconstriction and systemic hypertension. Recently, an endogenous Na+/K+ pump inhibitor was isolated from human plasma; this inhibitor is indistinguishable from the cardiac glycoside ouabain based on biochemical and immunological criteria. Its plasma concentration is close to the therapeutic range for ouabain (around 0.4 nmol/L). Since plant ouabain promotes natriuresis, vasoconstriction, and hypertension; endogenous ouabain may therefore control extracellular fluid volume and blood pressure. The highest plasma concentrations of endogenous ouabain and OLF were found in congestive heart failure, aldosterone producing adenoma, human and animal models of volume expanded hypertension (reduced renal mass and DOCA-salt hypertension), and in Milan hypertensive rats (MHS). Aldosterone antagonists (canrenone and canrenoate) exert both agonist and antagonist effects on the digitalis receptor site of the Na+/K+ pump. They are effective antihypertensive agents in animal models of hypertension sustained by OLF (reduced renal mass-Na+ and DOCA-salt hypertension in rats). Moreover, in a subgroup of essential hypertensives, 4 weeks of canrenoate administration reduced blood pressure, heightened red blood cell Na+/K+ pump activity, and antagonized ouabain-induced vasoconstriction. None of these effects was seen in the other hypertensives. These data suggest that aldosterone antagonists stimulate the Na+/K+ pump inhibited by endogenous ouabain and exert their antihypertensive action at least in part through this mechanism.

Treatment results in childhood acute lymphoblastic leukemia with a modified ALL-BFM'90 protocol: lack of improvement in high-risk group

We report results achieved in our institution with an acute lymphoblastic leukaemia risk-oriented treatment trial opened in January 1990 and closed on December 1995. The study was similar to the German ALL-BFM'90, except for using Protocol III for the standard-risk group, 2 g/m2 of methotrexate in Protocol M, and preventive cranial irradiation for the high-risk group only. The high-risk group included mostly patients with prednisone poor initial response and/or adverse cytogenetic features. This analysis included 374 patients, whose mean age was 6 years (range: 1 month-17 years). The overall complete remission rate was 94.4% (353/374) and the 5-year event-free survival (standard error) probability is 64(5)%. The 5-year event-free survival estimates for each risk group were: (1) high-risk group 37(5)%; (2) intermediate-risk group 66(1)%; and (3) standard-risk group 74(4)% (P = 0.0001). There are significantly higher-rates of isolated bone marrow and testicular relapses in the high-risk subset of patients. Our dismal results and the published experience, lead us to conclude that the optimal treatment for these high-risk acute lymphoblastic leukaemia patients is not currently known.

Skills training for pregnancy and AIDS prevention in Anglo and Latino youth

PURPOSE

This study tested social skills training (SST), didactic training (DT), and no training (NT) on adolescents' social skills for resisting peer pressure to engage in acquired immunodeficiency syndrome (AIDS) and pregnancy risk behavior.

METHODS

A total of 307 Latino and Anglo youth ages 13-18 years were assigned at random to receive 18 h of SST, 18 h of DT, or NT.

RESULTS

Significantly (p < 0.05) greater increases in assertiveness followed SST compared to DT or NT for three trained skills: condom negotiation, asking a friend about their sex/drug history, and discussing a friend's risk of AIDS. Untrained negotiation skills (e.g., purchasing a condom) did not increase significantly. SST did not result in increased assertiveness for refusal skills. DT increased knowledge of AIDS significantly more than SST; both DT and SST increased knowledge significantly more than NT.

CONCLUSIONS

Social skills training can increase assertiveness for certain negotiation skills that may decrease risk of AIDS for Latino, Anglo, and male and female adolescents. Both DT and SST can increase knowledge of AIDS prevention. Differences between experimental groups were supported by differences between trained and untrained skills within the SST condition, adding to discriminant validity.

Hodgkin disease in children: results of a prospective randomized trial in a single institution in Argentina

PURPOSE

To compare prospective treatment strategies in childhood Hodgkin disease to the following subsets of patients: a) Favorable prognostic group: these patients were randomized to receive 6 vs. 3 CVPP chemotherapy cycles without radiotherapy (CVPP: cyclophosphamide, vinblastine, procarbazine, and prednisone. The scheme was repeated every 28 days). b) Intermediate prognostic group: these patients were randomized to receive 6 cycles of CVPP or AOPE (AOPE: Adriamycin, vincristine, prednisone, and etoposide). Between the third and fourth cycles, all patients in this group received radiotherapy (RT)(30-40 Gy to initially involved areas). c) Unfavorable prognostic group: those patients received a single arm regimen of 6 cycles of CCOPP/CAPTe (3 of each combination) every 28 days. All these patients received radiotherapy (30-40 Gy to initially involved areas).

RESULTS

From October 1987 to December 1994, a total of 114 children and adolescents were evaluated. Mean age was 9 (range 2-17) years. There were 72 boys and 42 girls. With a median follow-up of 5 (range 1.5-8.7) years, at 80 months event-free survival (EFS) and overall survival (OS) for the whole cohort are 0.809 (SE: 0.04) and 0.873 (SE: 0.04), respectively (SE: Standard Error). Favorable prognostic group (n = 26) EFS is 0.831 (0.09) (Arm CVPP x 3:0.857 (0.13) and Arm CVPP x 6: 0.875 (0.08); p = non significant). Intermediate prognostic group (n = 64) EFS is 0.806 (0.05) (Arm CVPP x 6 + RT: 0.872 (0.05) and Arm AOPE x 6 + RT: 0.667 (0.10); p = 0.04). Unfavorable group (n = 24) EFS is 0.829 (0.07).

CONCLUSIONS

Results of treatment for the whole group are satisfactory. However, 3 cycles of CVPP without radiotherapy obtain equal EFS than 6 cycles without radiotherapy in the favorable prognostic group. In the intermediate prognostic group, 6 cycles of CVPP plus radiotherapy obtain a superior EFS than 6 cycles of AOPE plus radiotherapy. With the success of treatment for Hodgkin disease in children, future research needs to be focused in reducing toxicity without altering the excellent actual outcome.

Acute lymphoblastic leukemia presenting as acute hepatic failure in childhood

We report a 7-year old white girl who was admitted because of acute severe hepatic failure. Her complete blood count revealed pancytopenia and a bone marrow aspiration was consistent with acute lymphoblastic leukemia (ALL). Blasts cells were positive for cytoplasmic CD3 and cell surface T-associated markers. Viral, metabolic, immune and toxic causes for hepatic failure were ruled out. Treatment pre-phase with prednisone was started and liver function tests clearly improved after one-week therapy. However, due to her hepatic insufficiency, daily etoposide was administered orally during 15 days. On day 33 complete remission was achieved and hepatic function was normal, except for an increase in the bilirubin level which normalized on day 72. She received our current treatment for intermediate risk ALL and is still receiving continuation phase therapy, currently, with normal liver function and good tolerance to chemotherapy + 8 months after achieving complete remission.

Acute myeloid leukemia as a second malignancy: report of 9 pediatric patients in a single institution in Argentina

BACKGROUND

Acute myeloid leukemia (AML) is well-recognized as one of the most important second malignancies. We report the occurrence of secondary AML (sAML) in our institution.

PROCEDURE

From September 1987 to August 1996 we have observed sAML in 9 patients (median age 4 years), 5 of them previously treated for hematologic malignancies (group I): acute lymphoblastic leukemia (n = 2), AML (n = 1), non-Hodgkin lymphoma (n = 1). Hodgkin disease (n = 1), and 4 of these 9 patients treated for solid tumors (group II): neuroblastoma (n = 1), retinoblastoma (n = 1), Wilms tumor (n = 1), and central nervous system germinoma (n = 1).

RESULTS

All the patients had topoisomerase II inhibitors as part of treatment of their first malignancy, but only 5 patients received epipodophyllotoxins. Alkylating agents were part of primary therapy in 8 of 9 patients. The latency period for the development sAML was 26.5 (range = 2-55) months. The morphologic FAB features of sAML were M5 (n = 5), M4 (n = 3), and M2 (n = 1). Cytogenetic studies showed r11q23 in 3 patients, all of them with prior hematological malignancies. Initial therapy for sAML in all cases was chemotherapy (including cytarabine in combination with idarubicin and etoposide or doxorubicin or mitoxantrone). Three patients died during induction and 6 achieved complete hematologic response. Three of these patients remain disease free at +15, +51, and +99 months post-remission (including one post allogeneic BMT). The remaining 3 patients died, 1 in complete remission one month after diagnosis and 2 relapsed and died with progressive disease (one post allogeneic BMT).

CONCLUSIONS

Secondary AML is a sequela of oncologic treatments with specific cytogenetic abnormalities and poor outcome. A few patients can achieve long-term survival even with standard chemotherapy.

Childhood acute lymphoblastic leukemia: prognostic value of initial peripheral blast count in good responders to prednisone

PURPOSE

To assess the value of initial peripheral blast count in patients with acute lymphoblastic leukemia (ALL) and prednisone good response (PGR).

PATIENTS AND METHODS

From January 1990 to December 1995, 403 consecutive patients with newly diagnosed ALL were enrolled in the authors' protocol 1-ALL90-BFM/HPG. Prednisone good response was defined as a blast count of less than 1,000/microL and a prednisone poor response (PPR) as a blast count of at least 1,000/microL, both in peripheral smears, after 7 days of oral prednisone (60 mg/m2 per day) and one intrathecal dose of methotrexate. In the PGR group, patients were divided into two subgroups: patients who had less than 1,000 blasts/microL at diagnosis and those with at least 1,000 blasts/microL at diagnosis.

RESULTS

Three-hundred thirty-seven patients (90%) had PGR and 37 had (10%) PPR. At 5-year follow-up, event-free survival estimates were 67 +/- 3.8% and 38 +/- 8% for PGR and PPR, respectively (P = 0.0001). In the PGR group, 114 patients (34%) had an initial blast count of less than 1,000/microL and 223 (66%) had an initial blast count of at least 1,000/microL. The authors compared the clinical and laboratory characteristics of these subgroups at diagnosis and outcome and detected significant differences in white cell count, incidence of T immunophenotype, and presence of mediastinal or spleen enlargement. However, there were no differences in response to induction treatment, death in complete remission, relapses, or event-free survival probability.

CONCLUSIONS

In the PGR group, regardless of the initial blast count, both subgroups had the same outcome. The PGR group with an initial blast count of at least 1,000/microL had significantly higher white cell counts. T markers, and mediastinal or spleen enlargement at diagnosis. Response to prednisone is a practical, inexpensive, and good prognostic factor in childhood ALL.

Teenage pregnancy: a multiracial sociologic problem

Teenage pregnancy is not an epidemic in the United States. Because this is an emotional topic that receives high-decibel publicity in the press and on television, we wish to present the most recent factual information available on the subject and a more balanced perspective of the problem for physicians and other health professionals who care for women at the youngest age of the reproductive spectrum. Pregnancy during adolescence is a multiethnic sociologic problem that crosses all socioeconomic, ethnic, cultural, and geographic boundaries. Pregnancies in teenagers are decreasing (except in teenagers under age 15), not accelerating. New approaches for premature adolescent pregnancy and childbearing focus on adolescent peer pressure for behavior modification, prevention of pregnancy at a younger age, continuation of secondary education, and job training for both adolescent fathers and mothers.

Prospective study of the burden of acute gastroenteritis and rotavirus gastroenteritis in children less than 5 years of age, in Padova, Italy

BACKGROUND

Data on the burden of rotavirus gastroenteritis in Europe are needed to help understand the potential impact of introducing new rotavirus vaccines.

MATERIALS AND METHODS

As part of prospective observational study (Rotavirus gastroenteritis Epidemiology and Viral types in Europe Accounting for Losses in Public Health and Society Study, REVEAL) conducted in 2004--2005 in seven European countries, we studied, the characteristics of acute gastroenteritis and rotavirus gastroenteritis in children less than 5 years in primary care, emergency room and hospital settings (Padova, Italy).

RESULTS

A total of 757 children with acute gastroenteritis were included and enzyme-linked immunoabsorbent assay (ELISA) results were available for 725 cases. The overall estimated annual incidence for rotavirus gastroenteritis was 4.7%. Overall, rotavirus gastroenteritis was estimated to account for 43.6% of acute gastroenteritis cases. Among children with acute gastroenteritis (AGE) aged 6-23 months, 61.2% were rotavirus positive. Rotavirus gastroenteritis (RVGE) was responsible for 68.8% of hospitalizations, 61% of emergency consultations, and 33% of primary care consultations. The most prevalent serotype was G9 (84.4%) followed by G1 (11.8%). The relative risk for rotavirus gastroenteritis of being referred to hospital after an initial consultation in primary care was 3.37 (95% CI: 1.77-6.43) and 3.38 (95% CI: 2.28-5.01) for emergency room referral. Children with rotavirus gastroenteritis generally had more severe disease than children with rotavirus-negative gastroenteritis.

CONCLUSION

Rotavirus accounts for a significant proportion of acute gastroenteritis cases in children less than 5 years in Italy, many of whom require frequent primary care consultations, or care in emergency room or hospital settings.

Results of a BFM-based protocol for the treatment of childhood B-non-Hodgkin's lymphoma and B-acute lymphoblastic leukemia in Argentina

PURPOSE

To report the feasibility and results of a study based on the BFM-ALL. NHL/86 protocol for B-non-Hodgin's Lymphoma (NHL) and B-Acute Lymphoblastic Leukemia (B-ALL) in Argentina. Design. Prospective, single arm, non-randomized trial.

PATIENTS AND METHODS

From August 1988 to December 1993, 87 consecutive patients with B-NHL/B-ALL were admitted and 82 were eligible. The therapy was stratified according to stage. All patients received a cytoreductive prephase with cyclophosphamide and prednisone. Those with stage I-II were treated with three 5-day blocks of combined intense chemotherapy including dexamethasone, cyclophosphamidie, ifosfamide, cytarabine, teniposide, doxorabicin, and 500 mg/m2 of methotrexate as a 24 hour continuous infusion. Stage III received 6 blocks and those with stage IV/B-ALL received 6 intensified blocks in which 2 g/m2 of 24 hour continuous infusion methotrexate and vincristine were added. Triple intrathecal therapy was given for CNS prevention. After the first two blocks the response was assessed and those with a partial response were offered optionallya second look surgery or local radiotherapy.

RESULTS

With a median follow-up of 38 (range 16-71) months, the event-free survival (pEFS) for the whole group was 0.69 (Stage I-II n = 16 pEFS = 0.94, stage III n = 50 pEFS = 0.66, Stage IV n = 7 pEFS = 0.43, B-ALL n = 9 pEFS = 0.66). Patients with stage III abdominal tumors who achieved a partial response by imaging studies after induction had a significantly higher risk of relapse than those with a complete response (p = 0.02). Relapse was the most frequent event Toxicity was mainly hematological.

CONCLUSIONS

The application of this protocol was feasible in our setting and its results comparable to the German study. Patients with stage I-II had an excellent outcome. Those with stage III and B-ALL achieved an encouraging event-free survival, however those with abdominal tumors and partial response to induction chemotherapy fared less favourably. This strategy was less effective for patients with initial CNS disease.

Acute trilineage leukemia with monosomy of chromosome 7 following an acute promyelocytic leukemia

We describe an 8 year old boy who had received chemotherapy for an acute promyelocytic leukemia and developed a secondary leukemia 27 months after the diagnosis of this first malignancy. Blasts cells were positive for cytoplasmic markers CD22, CD3 and myeloperoxidase. Cell surface T and myeloid-associated markers were also detected. Cytogenetic study disclosed monosomy 7. The patient achieved complete remission, but relapsed 15 months later with identical immunophenotypic and cytogenetic findings. Three-lineage commitment is proved by the expression of specific criteria for myeloid, and lymphoid T and B typing. A multipotent immature progenitor must be the target of leukemogenic agents. The prognosis is obviously ominous.

Results of treatment with an intensive induction regimen using idarubicin in combination with cytarabine and etoposide in children with acute myeloblastic leukemia

We report results achieved in our institution with a study opened in July 1990 (similar to the German AML-BFM-87 in which daunorubicin was replaced by idarubicin in the induction phase and cranial preventive radiotherapy was omitted) and closed in December 1994, for the treatment of newly diagnosed acute myeloblastic leukemia (AML), without prior malignancies except for myelodysplasia. This evaluation included 68 patients, whose mean age was 6 years (range: 1 month-16 years). Thirty-nine were boys and 29 were girls. Complete remission rate was 80.9% (55/68), death on induction rate was 14.7% and induction failure rate was 4.4%. At median follow up of 38 months (range: 12-66 months), the 4-year event-free survival (EFS) estimate was 0.428 (S.E.: 0.062), event-free interval (EFI) estimate was 0.529 (S.E.: 0.07) and overall survival (OS) estimate was 0.44 (S.E.: 0.071). We conclude that idarubicin in combination with cytarabine and etoposide is a highly effective regimen for induction in children with AML. Although preventive cranial irradiation was not delivered, we have observed only one combined CNS relapse. Finally, we corroborate that in this setting two definite risk groups may be identified in children with AML.

Identification of novel NOTCH1 mutations: increasing our knowledge of the NOTCH signaling pathway

BACKGROUND

Alterations in the NOTCH1 signaling pathway are found in about 60% of pediatric T-ALL, but its impact on prognosis remains unclear.

PROCEDURE

We extended the previously published CoALL cohort (n = 74) to a larger cohort (n = 127) and additionally included 38 Argentine patients from ALL IC-BFM to potentially identify novel mutations and decipher a stronger discriminatory effect on the genotype/phenotype relationship with regard to early treatment response and long-term outcome.

RESULTS

Overall, 101 out of 165 (61.2%) T-ALL samples revealed at least one NOTCH1 mutation, 28 of whom had combined NOTCH1 and FBXW7 mutations. Eight T-ALL samples (4.8%) exclusively revealed FBXW7 mutations. Fifty-six T-ALL (33.9%) exhibited a wild-type configuration of either gene. Four novel NOTCH1 mutations were identified localized in the C-terminal PEST domain, in the rarely affected LNR repeat domain and in the ankyrin domain. Novel LNR mutations may contribute to a better understanding of the structure of the NOTCH1 negative regulatory region (NRR) and the R1946 mutation in the ankyrin domain may represent an unusual loss-of-function mutation.

CONCLUSIONS

Overall, NOTCH1 pathway mutations did not affect the relapse rate and outcome of the extended T-ALL cohort uniformly treated according to CoALL protocols, although NOTCH1 mutations were associated with good response to induction therapy (P = 0.009). Individually, HD and PEST domain mutations might exert distinct functional effects on cellular homeostasis under treatment NOTCH1 pathway activity with prognostic implications.

Subsequent malignant neoplasms in the pediatric age in retinoblastoma survivors in Argentina

BACKGROUND

Retinoblastoma survivors in low- and middle-income countries are exposed to high-intensity treatments that potentially place them at higher risk of early subsequent malignant neoplasms (SMNs).

METHODS

We followed 714 (403 [56.4%] nonhereditary and 311 [43.5%] hereditary) retinoblastoma survivors diagnosed from August 1987 to December 2016, up to the age of 16 years. We quantified risk of SMNs with cumulative incidence (CI) and standardized incidence ratios (SIR) analysis. Multivariate regression Cox model was used to determine the association of treatments and risk of SMNs.

RESULTS

Median follow-up was of 9 years (range: 0.18-16.9) and 24 survivors (3.36%) developed 25 SMNs (n = 22 hereditary, n = 2 nonhereditary). SMNs included sarcomas (osteosarcomas, Ewing sarcomas, rhabdomyosarcomas; n = 12), leukemias (n = 5), and central nervous system tumors (CNS; n = 3). All cases of acute myeloid leukemia (AML) and most of Ewing sarcomas occurred within 5 years of retinoblastoma diagnosis. The type of SMN was the main indicator of mortality (five of five patients with leukemias, six of 12 with sarcomas, and zero of three with CNS tumors died). Compared to the general population, radiation increased the risk of Ewing sarcoma in hereditary survivors by 700-fold (95% CI = 252-2422.6) and chemotherapy increased the risk of AML by 140-fold (95% CI = 45.3-436). The CI of SMNs for hereditary survivors was 13.7% (95% CI = 8.4-22.1) at 15 years.

CONCLUSION

Retinoblastoma survivors from Argentina are at higher risk of developing SMNs early in life compared to the general Argentinean population, especially those treated with radiation plus chemotherapy. AML and Ewing sarcoma presented within 5 years of retinoblastoma diagnosis are associated with chemotherapy and radiation exposure.

NPM1, FLT3 and CEBPA mutations in pediatric patients with AML from Argentina: incidence and prognostic value

Mutations in NPM1, FLT3 and CEBPA genes are found in 25-35 % of adult acute myeloblastic leukemia (AML) cases and correlate with prognosis. To date, there have been no reports about these mutations in pediatric AML from Argentina. The aims of the present study were to describe the incidence of NPM1, FLT3 and CEBPA mutations and to analyze their prognostic impact in this population. The incidences of these mutations within a population of 216 pediatric AML cases were: NPM1-mutated 4.2 %, CEBPA-mutated 1.9 %, FLT3-ITD 10.2 % and FLT3-TKD 7.9 %. Among 33 patients with normal karyotype, we found significantly higher frequencies for NPM1-mutated 24.2 % and CEBPA-mutated 12.1 %. Overall survival (pOS) for the 163 eligible non-acute promyelocytic leukemia cases was 46.2 ± 4.3 %, while leukemia-free survival probability was 51.0 ± 4.4 % (n = 135). The NPM1-mutated/FLT3-ITD-negative genotype showed better outcome than any other combined NPM1/FLT3 genotype; this difference was statistically significant within the group of high-risk patients (pOS ± SE 83.3 ± 15.2 % versus 33.1 ± 4.7 %; p = 0.0251). This is the first report of the frequencies of these mutations in Argentina. Despite the limited number of patients, a favorable prognosis of AML with genotype NPM1-mutated/FLT3-ITD-negative was confirmed. This is especially relevant within the high-risk group of patients, as it may contribute to the detection of patients with better prognosis, and thus avoid unnecessary treatment intensification.

Childhood acute promyelocytic leukemia: no benefit of all-trans-retinoic acid administered in a short-course schedule

From January 1990 to August 1997, 29 consecutive patients were treated with newly diagnosed primary acute promyelocytic leukemia (APL) at the authors' Institution. Of these, 27 (16 boys and 11 girls) were evaluable. Median age at diagnosis was 6.3 (range: 1.9-15.7) years. This population was treated with two consecutive protocols: 13 patients were included in the AML-HPG-90 protocol and 14 in the AML-HPG-95. The initial treatment was the same for both protocols: an induction 8-day phase with cytarabine, idarubicin, and etoposide was followed by a consolidation with cyclophosphamide, cytarabine, 6-mercaptopurine, vincristine, doxorubicin, and prednisone. Two courses of intensification with high-dose (HD) cytarabine and etoposide were given in the first study. Only one intensification course was administered in the second study, with HD cytarabine plus idarubicin or etoposide decided by randomization. Complete remission was achieved in 67% (18/27) of cases. Mortality on induction was quite high, 30% (8/27) mainly due to hemorrhages from disseminated intravascular coagulation (DIC). The event-free survival estimate for all patients was 0.47 (SE: 0.1). From April 1994, all-trans-retinoic acid (ATRA) was administered just during the first days of the induction phase (median: 9, range: 2-27) to stop or prevent DIC. Eighteen patients received ATRA and 9 did not. Three patients developed signs of ATRA syndrome during the first days of administration but no one died due to this toxicity. The impact of a short course of ATRA on early control of DIC was studied by analyzing the number of platelet, cryoprecipitate, and fresh frozen plasma transfusions during the induction phase in both groups. No statistical differences in complete remission rate, early mortality, need of transfusion of blood components for DIC, and survival estimates could be established between patients who received ATRA and those who did not. ATRA used in a short-course schedule during induction of APL did not stop early mortality due to DIC. Moreover, survival results did not improve with this method of ATRA usage. Longer periods of ATRA administration during APL therapy are strongly recommended.

Common histopathological changes in aged human orbital arteries

The physiology of the orbital arteries supplying the eye is currently under intensive investigation. However, while the anatomical distribution of these vessels in humans is well known, their normal histology and age-related or other pathologic alterations have hardly been studied. We obtained at autopsy 10 orbits from persons aged > or = 74 years, and two orbits from a person aged 47 years. Specimens were taken from 20 locations along the orbital arteries, from the internal carotid to the globe, and studied by light microscopy. We observed the following arteriosclerotic changes, in order of decreasing frequency: intimal hyperplasia, medial atrophy, atherosclerotic fibrous plaques, and calcifications of the internal elastic lamina. As a rule, the intensity of the changes decreased from proximal to distal. This study shows that aged human orbital arteries are readily subject to degenerative changes that may play an important role in ophthalmic vascular disease.

Inhibition of furosemide-sensitive cation transport and activation of sodium-lithium exchange by endogenous circulating factor(s) in Bartter's and Gitelman's syndromes

BACKGROUND

The nature of the cellular abnormality causing hypokalemia, hypotension, and hypovolemia in Bartter's and Gitelman's syndromes is still being debated. In fact, despite the recent descriptions of an array of nonconservative missense or point mutations in some ion transporters and in K+ channel, the lack of detectable defects in some patients suggests that other abnormalities of cell ion homeostasis may be involved in the pathophysiology of these syndromes. The study of the activity of cell ion transporters in patients with these syndromes using red blood cells (RBC) as a cellular model never investigated the role of plasma factor(s) affecting ion transport.

OBJECTIVE

To evaluate the effect of plasma from patients with these syndromes on furosemide-sensitive lithium efflux (FSLE) from lithium (Li+)-loaded RBC of healthy subjects in vitro.

METHODS

RBC of healthy controls were loaded with Li+ in the presence of nystatin and FSLE was evaluated in the presence of various concentrations of plasma from controls and patients with the two syndromes.

RESULTS

Plasma from controls did not affect FSLE (0.08 +/- 0.02 mmol/l cells per h with 1:4 vol:vol and 0.07 +/- 0.02 mmol/l cells per h with 1:2 vol:vol plasma dilution). In contrast, doubling concentrations of plasma from patients with either syndrome in the efflux solution halved FSLE (from 0.10 +/- 0.0 mmol/l cells per h with 1:4 vol:vol to 0.05 +/- 0.01 mmol/l cells per h with 1:2 vol:vol plasma dilution, P < 0.05). Na+/Li+ exchange was significantly greater for RBC from patients with either syndrome than it was for RBC from controls (0.373 +/- 0.06 versus 0.257 +/- 0.01 mmol/l cells per h, P < 0.01), but the kinetic properties of furosemide-sensitive Na+-K+-2Cl- cotransport were similar.

CONCLUSION

These data provide evidence for the hypothesis that plasma factor(s) affect ion transport in patients with these two syndromes. Since FSLE estimates Na+-K+-2Cl- cotransport the data suggest that plasma factor(s) contribute(s) to K+ wasting, hypokalemia, and hypotension by inhibiting cotransport in patients with these syndromes. The increase of Na+/Li+ exchange is most likely a secondary phenomenon associated with the hypermineralocorticoid state.

Effect of protein kinase C and insulin on Na+/H+ exchange in red blood cells of essential hypertensives

The kinetic properties of sodium-proton exchange are abnormal in human red blood cells of hypertensive patients and it has been demonstrated that the transport protein undergoes post-translational modifications able to affect its kinetic properties. Protein kinase C (PKC) activation decreases the affinity constant for intracellular protons while insulin increases the maximal rate of proton translocation. The present study therefore aimed to examine the relationships among PKC activity, fasting insulin levels and the kinetic behaviour of sodium-proton exchange in red blood cells from 20 normotensives and 36 hypertensives. In comparison with normotensive subjects, hypertensive patients had higher body mass index (26.2 +/- 0.7 vs 23.6 +/- 0.6 kg/m2, P < 0.05), higher fasting insulin levels (93.2 +/- 10.8 vs 38.6 +/- 2.9 pmol/L), increased maximal velocity of proton translocation (37.9 +/- 2.7 vs 27.6 +/- 1.9 mmol/L per cell x h, P < 0.05), and reduced Hill's coefficient (1.6 +/- 0.1 vs 2.0 +/- 0.1, P < 0.01) of sodium-proton exchange. Basal PKC activity of the cytosol and membrane was similar in the study groups. However, after treatment with 1 micromol/L phorbol 12-myristate 13-acetate (PMA) for 10 min, membrane PKC activity was stimulated to a larger extent in hypertensives (to 181 +/- 8 pmol/min/mg protein) than in normotensives (to 136 +/- 6 pmol/min/mg protein, P < 0.01). The PMA stimulated PKC activity was positively correlated to fasting insulin levels (r = 0.59, P < 0.01). Stimulation of membrane PKC by PMA corrected the low Hill's coefficient for H(i)+ activation of sodium-proton exchange in the hypertensives, while the constant for half maximal activation for intracellular protons (ie, the affinity for intracellular protons) decreased to a similar extent in both groups. The maximal transport rate was unaffected by PMA. These results indicate that the abnormal proton activation of red blood cell sodium-proton exchange in hypertensives reflects an abnormal regulation of PKC translocation to the cell membrane, associated to hyperinsulinaemia and probably insulin resistance. Therefore, post-translational modifications of the transport protein(s) account for the altered kinetic behaviour of sodium-proton exchange in hypertensives.