Effects of prandial glycemic changes on objective fetal heart rate parameters

BACKGROUND

There is confusion in the literature about the potential effect of maternal glucose levels on the fetal heart rate (FHR) cardiotocographic interpretation.

METHODS

STUDY DESIGN

prospective clinical descriptive study.

SUBJECTS

21 pregnant women with diabetes mellitus, 23 women with gestational diabetes and 18 healthy non-diabetic pregnant volunteers (control group).

TREATMENT

maternal capillary glucose measurement and objective FHR analysis (Oxford System 8002) pre- and 1 h post-meal.

STATISTICAL ANALYSIS

descriptive statistics. Student t-tests and Pearson correlation studies.

RESULTS

Maternal capillary glucose levels ranged between 2.7-10.5 mmol/l pre-meal and 4.2 14.8 mmol/l post-meal. The differences between objective FHR parameters pre- and postmeal were not significant in any of the groups of women studied. No correlation was found between prandial glycemic and FHR changes. Women with optimal and suboptimal glycemic control exhibited similar objective FHR parameters pre- and post-meal. Women with gestational diabetes showed similar prandial cardiotocographic changes irrespective of whether they were on insulin therapy or on hypoglycemic diet only.

CONCLUSIONS

Objective FHR parameters are unaffected by prandial glycemic changes over a wide range of maternal glucose levels. Timing the non-stress test in relation to the meals seems irrelevant in clinical practice.

Graft-versus-tumour effect in non-small-cell lung cancer after allogeneic peripheral blood stem cell transplantation

Clinical evidence of a graft-vs.-tumour effect in solid tumours after haematopoietic stem cell transplantation is lacking. We report for the first time a complete and durable regression of a stage IB non-small-cell lung carcinoma in a patient who had received an allogeneic peripheral blood haematopoietic stem cell transplant for acute myeloblastic leukaemia in first complete remission. Disappearance of the tumour coincided with development of graft-vs. -host disease. This suggests that simultaneous generation of cytotoxic T lymphocytes against lung carcinoma cells could have been responsible for the regression. This unique clinical observation broadens the possibility of using allogeneic haematopoietic stem cell transplantation in treating neoplasias lacking significant sensitivity to chemotherapy.

Cutaneous promyelocytic sarcoma at sites of vascular access and marrow aspiration. A characteristic localization of chloromas in acute promyelocytic leukemia?

Extramedullary disease (EMD) is a rare clinical event in acute promyelocytic leukemia (APL). Although the skin is involved in half of the reported EMD cases, the occurrence of cutaneous promyelocytic sarcoma (PS) has been described very rarely. We report here three cases of PS which have the peculiarity of appearing at sites of punctures for arterial and venous blood and marrow samples (sternal manubrium, antecubital fossa, wrist over the radial artery pulse, catheter insertion scar). At presentation, all patients had hyperleukocytosis and a morphologic diagnosis of microgranular acute promyelocytic leukemia variant confirmed at the genetic level by demonstration of the specific chromosomal translocation t(15;17). A BCR3 type PML/RARa transcript was documented in the two patients for whom diagnostic RT-PCR was available. Patients had morphologic bone marrow remission at the time the PS appeared. A predilection for the development of cutaneous PS at sites of previous vascular damage has been noted, but the pathogenesis remains largely unknown. A potential role for all-trans retinoic acid has been advocated, although one of the three patients in our series had received no ATRA. A review of the literature revealed six similar cases and hyperleukocytosis at diagnosis was a consistent finding in all of them. A careful physical examination of these particular sites in the follow-up of patients at risk, as well as cutaneous biopsy and laboratory examination of suspected lesions are strongly recommended.

Site-directed mutagenesis of the regulatory domain of Escherichia coli carbamoyl phosphate synthetase identifies crucial residues for allosteric regulation and for transduction of the regulatory signals

Carbamoyl phosphate (CP), the essential precursor of pyrimidines and arginine, is made in Escherichia coli by a single carbamoyl phosphate synthetase (CPS) consisting of 41.4 and 117.7 kDa subunits, which is feed-back inhibited by UMP and activated by IMP and ornithine. The large subunit catalyzes CP synthesis from ammonia in three steps, and binds the effectors in its 15 kDa C-terminal domain. Fifteen site-directed mutations were introduced in 13 residues of this domain to investigate the mechanism of allosteric modulation by UMP and IMP. Two mutations, K993A and V994A, decreased significantly or abolished enzyme activity, apparently by interfering with the step of carbamate synthesis, and one mutation, T974A, negatively affected ornithine activation. S948A, K954A, T974A, K993A and K993W/H995A abolished or greatly hampered IMP activation and UMP inhibition as well as the binding of both effectors, monitored using photoaffinity labeling and ultracentrifugation binding assays. V994A also decreased significantly IMP and UMP binding. L990A, V991A, H995A, G997A and G1008A had more modest effects or affected more the modulation by and the binding of one than of the other nucleotide. K993W, R1020A, R1021A and K1061A were without substantial effects. The results confirm the independence of the regulatory and catalytic centers, and also confirm functional predictions based on the X-ray structure of an IMP-CPS complex. They prove that the inhibitor UMP and the activator IMP bind in the same site, and exclude that the previously observed binding of ornithine and glutamine in this site were relevant for enzyme activation. K993 and V994 appear to be involved in the transmission of the regulatory signals triggered by UMP and IMP binding. These effectors possibly change the position of K993 and V994, and alter the intermolecular contacts mediated by the regulatory domain.

The goodpasture autoantigen. Identification of multiple cryptic epitopes on the NC1 domain of the alpha3(IV) collagen chain

Goodpasture (GP) disease is an autoimmune disorder in which autoantibodies against the alpha3(IV) chain of type IV collagen bind to the glomerular and alveolar basement membranes, causing progressive glomerulonephritis and pulmonary hemorrhage. Two major conformational epitope regions have been identified on the noncollagenous domain of type IV collagen (NC1 domain) of the alpha3(IV) chain as residues 17-31 (E(A)) and 127-141 (E(B)) (Netzer, K.-O. et al. (1999) J. Biol. Chem. 274, 11267-11274). To determine whether these regions are two distinct epitopes or form a single epitope, three GP sera were fractionated by affinity chromatography on immobilized NC1 chimeras containing the E(A) and/or the E(B) region. Four subpopulations of GP antibodies with distinct epitope specificity for the alpha3(IV)NC1 domain were thus separated and characterized. They were designated GP(A), GP(B), GP(AB), and GP(X), to reflect their reactivity with E(A) only, E(B) only, both regions, and neither, respectively. Hence, regions E(A) and E(B) encompass critical amino acids that constitute three distinct epitopes for GP(A), GP(B), and GP(AB) antibodies, respectively, whereas the epitope for GP(X) antibodies is located in a different unknown region. The GP(A) antibodies were consistently immunodominant, accounting for 60-65% of the total immunoreactivity to alpha3(IV)NC1; thus, they probably play a major role in pathogenesis. Regions E(A) and E(B) are held in close proximity because they jointly form the epitope for Mab3, a monoclonal antibody that competes for binding with GP autoantibodies. All GP epitopes are sequestered in the hexamer configuration of the NC1 domain found in tissues and are inaccessible for antibody binding unless dissociation of the hexamer occurs, suggesting a possible mechanism for etiology of GP disease. GP antibodies have the capacity to extract alpha3(IV)NC1 monomers, but not dimers, from native human glomerular basement membrane hexamers, a property that may be of fundamental importance for the pathogenesis of the disease.

Incidence, characterization and prognostic significance of chromosomal abnormalities in 640 patients with primary myelodysplastic syndromes. Grupo Cooperativo Español de Citogenética Hematológica

Recently, a consensus International Prognostic Scoring System (IPSS) for predicting outcome and planning therapy in the myelodysplastic syndromes (MDS) has been developed. However, the intermediate-risk cytogenetic subgroup defined by the IPSS includes a miscellaneous number of different single abnormalities for which real prognosis at present is uncertain. The main aims of this study were to evaluate in an independent series the prognostic value of the IPSS and to identify chromosomal abnormalities with a previously unrecognized good or poor prognosis in 640 patients. In univariate analyses, cases with single 1q abnormalities experienced poor survival, whereas those with trisomy 8 had a higher risk of acute leukaemic transformation than the remaining patients (P = 0.004 and P = 0.009 respectively). Patients with single del(12p) had a similar survival to patients with a normal karyotype and showed some trend for a better survival than other cases belonging to the IPSS intermediate-risk cytogenetic subgroup (P = 0.045). Multivariate analyses demonstrated that IPSS cytogenetic prognostic subgroup, proportion of bone marrow blasts and haemoglobin level were the main prognostic factors for survival, and the first two characteristics and platelet count were the best predictors of acute leukaemic transformation risk. A large international co-operative study should be carried out to clarify these findings.

Chronic myeloid leukemia with expression of ALL-type BCR/ABL transcript: a case-report and review of the literature

CML with exclusive expression of ALL-type bcr/abl has only been rarely described. In some cases, the presence of this fusion gene has been associated to a differentiated subtype of CML that share some features with CMML, while in another case this molecular hallmark has been associated to a bad prognosis of the disease with a blast phase as clinical presentation or an early transformation to blast phase. We report a case of a 30-year-old woman who was diagnosed of CML in chronic phase in May 1989. She received treatment first with busulfan, achieving hematological remission and afterwards with interferon and Hydroxiurea. In February 1998, she was admitted at our hospital for an ABSCT. Then, molecular studies were performed. Multiplex PCR revealed the presence of a 481 bp product identified as the ela2 bcr/abl transcript and confirmed by sequencing. After 9 years from diagnosis, the patient remains in hematological remission and in good clinical condition.

Liver disease as primary manifestation of multiple myeloma in a young man

We report a 27-year-old man who presented with fatigue, moderate weight loss and progressive abdominal distension as primary manifestations of a light-chain multiple myeloma (MM). Liver scan showed an enlarged liver with multiple low attenuation areas. Liver biopsy revealed sinusoidal infiltration by small size cells identified as Kappa light chain-producing primitive plasma cells by immunohistochemistry. The patient responded to three courses of EDAP. Subsequently he received intensive therapy with busulfan/melfalan and a peripheral blood stem cell transplantation enriched for CD34+ cells from his HLA-identical brother. No acute graft-versus-host disease was detected. Now, 12 months after transplant, the patient is asymptomatic.

Photoaffinity labeling with the activator IMP and site-directed mutagenesis of histidine 995 of carbamoyl phosphate synthetase from Escherichia coli demonstrate that the binding site for IMP overlaps with that for the inhibitor UMP

Photoaffinity labeling with IMP was used to attach covalently this activator to its binding site of Escherichia coli carbamoyl phosphate synthetase. We now identify histidine 995 of the large enzyme subunit as the amino acid that is cross-linked with IMP. The identification was carried out by comparative peptide mapping in two chromatographic systems of peptides differentially labeled with [3H]IMP and with the labeled inhibitor [14C]UMP, followed by automated Edman degradation and radiosequence analysis. Site-directed substitution of His995 by alanine confirmed His995 to be the only amino acid in the protein forming a covalent adduct with IMP. The His995Ala mutant protein was soluble and active and exhibited normal kinetics for the activator ornithine and for the substrates in the presence of ornithine. However, the mutation selectively induced changes in the activation by IMP and the inhibition by UMP, and it abolished the photolabeling of the enzyme by IMP without affecting the photolabeling by the inhibitor UMP. Since UMP is cross-linked to Lys993 [Cervera, J., et al. (1996) Biochemistry 35, 7247-7255] only two residues upstream of the site of IMP labeling, the results provide structural evidence for earlier proposals which suggested that UMP and IMP bind in a single or overlapping site. The two residues are within the region previously proposed as the binding fold for the nucleotide effectors. In the crystal structure of the enzyme, Lys993 and His995 are exposed and line a crevice where a Pi molecule was found [Thoden, J. B., et al. (1997) Biochemistry 36, 6305-6316]. UMP and IMP appear to bind in this crevice, possibly toward the C-side of the beta-sheet in a Rossman fold. Their binding in this site is consistent with the selectivity of adduct formation of UMP with Lys993 and of IMP with His995. It is also consistent with the nonessentiality of His995 for the binding, since the interactions with other residues that line the crevice must contribute a large part of the binding energy. The lack of an effect of the mutation on the activation by ornithine is consistent with the binding of this activator in a separate site in the protein.

Localization of the site for the nucleotide effectors of Escherichia coli carbamoyl phosphate synthetase using site-directed mutagenesis

Replacement by alanine of Ser-948, Thr-974 and Lys-954 of Escherichia coli carbamoyl phosphate synthetase (CPS) shows that these residues are involved in binding the allosteric inhibitor UMP and the activator IMP. The mutant CPSs are active in vivo and in vitro and exhibit normal activation by ornithine, but the modulation by both UMP and IMP is either lost or diminished. The results demonstrate that the sites for UMP and IMP overlap and that the activator ornithine binds elsewhere. Since the mutated residues were found in the crystal structure of CPS near a bound phosphate, Ser-948, Thr-974 and Lys-954 bind the phosphate moiety of UMP and IMP.

Autologous blood stem cell transplantation for acute myeloblastic leukemia in first complete remission. Intensification therapy before transplantation does not prolong disease-free survival

BACKGROUND AND OBJECTIVE

To compare the clinical results of two consecutive therapeutic protocols including autologous blood stem cell transplantation (ABSCT) for patients with de novo acute myeloblastic leukemia (AML) in first complete remission (CR1).

DESIGN AND METHODS

Between November 1989 and January 1997, 50 patients with AML in CR1 underwent ABSCT using two consecutive protocols. In the first one (Group A, 25 patients) peripheral blood stem cells (PBSC) were collected after induction and consolidation chemotherapy courses, and ABSCT was performed immediately thereafter. In the subsequent 25 patients (Group B), PBSC were collected after consolidation alone, and a further chemotherapy course with intermediate dose cytarabine (Ara-C 1 g/m2/12 h x3 days) and mitoxantrone (12 mg/m2/d x3 days) was administered as early intensification. The conditioning regimen consisted of busulfan (16 mg/kg) and cyclophosphamide (200 mg/kg) in every case.

RESULTS

Hematopoietic engraftment was slightly quicker in Group B, with median times to reach 0.5 x 10(9) neutrophils/L and 20 x 10(9) platelets/L being 13 and 12 days in Group A and 12 and 11 days in Group B, respectively. There were three graft failures (8%) (2 in Group A and 1 in Group B) and three transplant-related deaths (8%) (2 in Group A and 1 in Group B). No significant differences were observed between the groups in terms of relapse (64% at 4-years in Group A and 81% in Group B). Likewise, the actuarial 4-year disease-free survival (DFS) was not significantly different between the two groups (32% v 18%).

INTERPRETATION AND CONCLUSIONS

Our study confirms that AML patients in CR1 receiving ABSCT have rapid engraftment with low mortality. However, autologous transplants with PBSC collected after consolidation chemotherapy were still associated with a high rate of relapse (RR). This RR was not apparently reduced by the administration of intermediate dose Ara-C before transplantation.

Prolonged molecular remission after PML/RAR alpha-positive autologous peripheral blood stem cell transplantation in acute promyelocytic leukemia: is relevant pretransplant minimal residual disease in the graft?

The contribution of residual malignant cells contaminating the autologous graft with the occurrence of post-transplant relapse in acute myeloid leukemia (AML) is still unclear. The presence of a specific molecular marker (the PML/RAR alpha rearrangement) in acute promyelocytic leukemia (APL) offers the opportunity to investigate better the pathogenesis of disease recurrence after transplant. We report an APL patient who received high-dose chemotherapy and peripheral blood stem cell (PBSC) autograft in second hematologic remission. Two leukaphereses that tested PML/RAR alpha positive by RT-PCR were obtained during the post-reinduction hematopoietic recovery, while the patient also tested PCR positive in the BM, and was reinfused after myeloablative chemotherapy (BUCY4), when the patient had spontaneously converted to PCR negative in the marrow. At present, he remains in continuous molecular and hematologic remission 22 months after PBSC transplantation. This is the second report of an APL patient who was transplanted in molecular remission with a PML/RAR alpha-positive PBSC autograft. As in the previous report, the prolonged clinical and molecular remission experienced post-transplant suggests that autologous PBSC infusion is still worthy of consideration for patients with APL in spite of the detection of PML/RAR alpha-positive cells in the PBSC collections. Possible underlying mechanisms and the potential role of molecular monitoring of the graft, as well as the host, before and after transplant, in patients with APL undergoing autologous HSCT are also discussed.

Carbamate kinase from Enterococcus faecalis and Enterococcus faecium--cloning of the genes, studies on the enzyme expressed in Escherichia coli, and sequence similarity with N-acetyl-L-glutamate kinase

Carbamate kinase (CK) catalyzes the reversible reaction NH2COO- + ATP <--> NHCOOPO3(2-) + ADP, serving to synthesize ATP from carbamoyl phosphate in those microorganisms that derive energy from anaerobic arginine degradation via the arginine dihydrolase pathway. We report here the cloning and sequencing of the CK gene from Enterococcus faecalis and Enterococcus faecium and we demonstrate that the amino acid sequence of CK is identical in the two species. The enzyme, expressed and isolated from Escherichia coli using simple purification procedures, was used to generate crystals suitable for X-ray studies and to investigate the utilization by CK of bicarbonate and other carbamate analogs. CK had a bicarbonate-dependent ATPase activity and, therefore, is able to synthesize carboxyphosphate, an unstable compound that is an intermediate in the reactions catalyzed by carbamoyl-phosphate synthetase (CPS) and by biotin carboxylase. Other functional similarities with CPS include the utilization of acetate by CK with a similarly high Km and the similar Km values of CK for carbamate and of CPS for bicarbonate. Enterococcal CK was inhibited by adenosine(5')pentaphospho(5')adenosine (Ap5A) and Ap6A and, less powerfully, by Ap4A, whereas Ap3A is essentially non-inhibitory. Thus, inhibition by Ap5A seems not to be a valid criterion to differentiate between CK and CPS, for the two enzymes can be inhibited by Ap5A. All these results support the relatedness of CK and CPS. Finally, we used limited proteolysis: (a) to localize the epitopes for monoclonal antibodies obtained against CK; (b) to demonstrate the importance of the C-terminus for enzyme activity; and (c) to show that Arg158 is highly exposed and may be essential for activity. Comparison of the sequence of CK with known protein sequences demonstrates considerable similarity of CK with bacterial N-acetylglutamate kinases, strongly suggesting that these two enzymes may share a similar structure and the same catalytic mechanism.

[Invasive fungal infections in patients with blood disorders]

BACKGROUND

Invasive fungal infections (IFI) are severe infectious complications frequently observed in patients with hematological disorders. The aims of this study were to analyse the characteristics of this particular type of infection in a large series of a single institution and to determine the factors associated with the outcome and therapeutic response.

PATIENTS AND METHODS

This study reviews the clinical and microbiological features of 155 IFI occurred among 144 patients with hematologic disorders throughout a period of 17 years in a single institution.

RESULTS

In 118 cases (82%) the diagnosis was acute leukemia. The main risk factors for developing IFI included a persistent and profound granulocytopenia, the use of broad-spectrum antibacterial agents, indwelling central venous catheters and the damage of normal host barriers following intensive cytotoxic chemotherapy. Candida (65 cases [44%]) and Aspergillus (38 cases [26%]) species were the most common fungal species isolated. An increasing number of IFI were caused by fungi previously considered as contaminants or harmless colonizers. The outcome of IFI was favourable in 78 cases (50%). The most important prognostic factors for the outcome of the IFI were the phase of cytotoxic chemotherapy (p = 0.005), the response of the underlying disease to the cytotoxic chemotherapy (p < 0.00001), and the recovery of neutropenia during the infection course (p < 0.00001). An earlier use of empirical antifungal therapy was also associated with a better outcome.

CONCLUSIONS

In spite of earlier treatment and regardless the development of new antifungal agents, the prognosis of IFI in patients with hematological malignancies remains poor. The use of hematopoietic growth factors, through their impact in the duration and severity of neutropenia, may prove valuable the management of IFI in this setting.

Radioactivity measurements on migrating birds (Turdus philomelos) captured in the Comunidad Valenciana (Spain)

The radionuclides 137Cs, 134Cs and 90Sr have been measured in edible tissues and bones of migratory birds (song-thrushes, Turdus philomelos) from central and northern Europe and captured in the Comunidad Valenciana, Spain in the 1994 autumn-winter season. Eight years after the Chernobyl accident, extensive agricultural lands in Europe are still contaminated and this study shows that there was a transfer of radioactive isotopes to the captured migratory song-thrushes. The whole-body dose commitment to humans consuming these birds is estimated.

[Immunohematologic study and transfusion approach to patients with public antibodies]

OBJECTIVES

To analyze the different immunohematologic studies required to identify anti-red cell antibodies directed against high incidence antigens and comment the best tranfusion management.

PATIENTS AND METHODS

Five patients with suspected anti-red cell alloantibodies directed against high frequency antigens are reported. After a positive antibody screening test (AST), an agglutination test with a commercial panel of 24 red cells was performed. Red cells were treated with proteolytic enzymes and AET to try to identify the circulating antibody. However, it was necessary to send the samples to reference laboratories for definitive identification. In order to evaluate the haemolytic potential of the antibody serum samples were treated with DTT and immunoglobulin subtype was studied with the capillary agglutination test. Finally, we analyze the half life of Cr51 labelled red cells. To obtain compatible blood for transfusion, autologous transfusion and cross-match with blood from direct relatives were performed.

RESULTS

AST was positive in every case. A decrease in the agglutination test was observed after ficin treatment in two patients, and an increase in the remaining. The treatment of red cells with ZZAP and AET resulted in a decrease of agglutination in three cases and an increase in the remaining two. Specificity of the antibodies was as follows: anti-Cellano (two cases), anti-Ku (one case) and anti-Yta (two cases). Anti-Kell antibodies were IgG1 and anti-Cartwright antibodies were IgG4. One patient was transfused with autologous blood alone, another patient received compatible blood from direct relatives. A third patient was transfused both with autologous and allogeneic compatible blood. The fourth patient did not need red cell transfusion and, finally the last patient had to be transfused with incompatible blood but no postransfusion haemolysis was observed.

CONCLUSIONS

In patients with anti-red cell antibodies against high-frequency antigens, red blood cells treatment with proteolytic enzymes (ZZAP, ficin) and AET are useful techniques to approach to their identification. Beside this, the study of type and subtype of Ig are necessary to know the haemolytic activity of the antibody. Regarding the transfusional management, autologous transfusion, crossmatch with blood from direct relatives and cryopreservation of compatible blood are the most adequate attitudes to cover future needs.

Photoaffinity labeling with UMP of lysine 992 of carbamyl phosphate synthetase from Escherichia coli allows identification of the binding site for the pyrimidine inhibitor

UMP is a highly specific reagent for photoaffinity labeling of the allosteric inhibitor site of carbamyl phosphate synthetase (CPS) from Escherichia coli and has been found to be photoincorporated in the COOH-terminal domain of the large subunit [Rubio et al. (1991) Biochemistry 30, 1068-1075]. In the present work we identify lysine 992 as the residue that is covalently attached to UMP. This identification is based on two lines of evidence. First, [14C]UMP is found to be incorporated between residues 939 and 1006, as shown by peptide mapping and by mass estimates of [14C]UMP-peptides generated by chemical and enzymatic cleavage of CPS. Secondly, we have purified two radioactive peptides derived exclusively from those enzyme molecules (approximately 5% of the total enzyme) that had incorporated [14C]-UMP. Edman analyses show the sequences of the labeled peptides (989)LVNXVHEGRPHIQD and (989)LVNXVHE to be overlapping. Since neither a phenylthiohydantoin (Pth) derivative (in cycle 4) nor any radioactivity is released from the membrane during sequencing, we can conclude that Lys992 and [14C]-UMP form a covalent adduct that remains bound to the membrane. Formation of this adduct agrees with all of the evidence and with the finding that UMP labeling prevents trypsin cleavage at Lys992. Lysine 992 is invariant in those CPSs that are inhibited by UMP, and is located 30 residues upstream of the site whose phosphorylation in hamster CAD reduces inhibition of CAD by UTP. Multiple sequence alignment of the residues surrounding Lys992 of the E. coli enzyme and the corresponding residues of the yeast and animal enzymes supports the existence of a uridine nucleotide binding fold in this region of the protein. We conclude that sequence changes in the binding fold provide a structural basis for the different regulatory properties found among CPSs I, II, and III.