Reversed Holocene temperature-moisture relationship in the Horn of Africa.

Anthropogenic climate change is predicted to severely impact the global hydrological cycle1, particularly in tropical regions where agriculture-based economies depend on monsoon rainfall2. In the Horn of Africa, more frequent drought conditions in recent decades3,4 contrast with climate models projecting precipitation to increase with rising temperature5. Here we use organic geochemical climate-proxy data from the sediment record of Lake Chala (Kenya and Tanzania) to probe the stability of the link between hydroclimate and temperature over approximately the past 75,000 years, hence encompassing a sufficiently wide range of temperatures to test the 'dry gets drier, wet gets wetter' paradigm6 of anthropogenic climate change in the time domain. We show that the positive relationship between effective moisture and temperature in easternmost Africa during the cooler last glacial period shifted to negative around the onset of the Holocene 11,700 years ago, when the atmospheric carbon dioxide concentration exceeded 250 parts per million and mean annual temperature approached modern-day values. Thus, at that time, the budget between monsoonal precipitation and continental evaporation7 crossed a tipping point such that the positive influence of temperature on evaporation became greater than its positive influence on precipitation. Our results imply that under continued anthropogenic warming, the Horn of Africa will probably experience further drying, and they highlight the need for improved simulation of both dynamic and thermodynamic processes in the tropical hydrological cycle.

Exponentially fitted open Newton-Cotes differential methods as multilayer symplectic integrators.

Classical open and closed Newton-Cotes differential methods possessing the characteristics of multilayer symplectic structures have been constructed in the past. In this paper, we study the exponentially fitted open Newton-Cotes differential methods of order two, four, and six. It is shown that these integrators, just as their classical counterparts, preserve the volume in the phase space of a Hamiltonian system. They can be converted into a multilayer symplectic structure so that volume-preserving integrators of a Hamiltonian system are obtained. A numerical example has been carried out to show the effectiveness of the present differential method.

Assessment of ventricular septal defect closure by intraoperative epicardial ultrasound.

Intraoperative epicardial two-dimensional echocardiographic imaging, color flow mapping and contrast echocardiography were used in 31 patients after patch closure of a ventricular septal defect to determine their respective values in the assessment of residual shunting after cardiopulmonary bypass and for the prediction of long-term results. Epicardial imaging showed no incidence of patch dehiscence. Residual shunting detected by color flow mapping or contrast echocardiography was graded into one of four categories (0 to III). Real time analysis of color flow mapping studies suggested no shunting (grade 0) in 2 patients, grade I shunting in 20, grade II in 8 and grade III in 1; contrast studies suggested grade 0 in 15, grade I in 6, grade II in 8 and grade III in 2. Interobserver variation in real time encoding of grade I or II shunting was 25% by color flow mapping and 6% by contrast echocardiography. Subsequent frame by frame analysis revealed that both diastolic and early systolic right ventricular turbulence gave rise to false positive results during real time analysis of color flow mapping studies. Color flow mapping allowed exact localization of residual shunting, whereas contrast echocardiography allowed better semiquantification. Postbypass results were correlated in 30 patients with late postoperative precordial studies (mean interval 7.5 months). Persistent shunts were found in 6 (20%) of 30 patients. No patient required reoperation for residual shunting. The predictive value of immediate grade I or II shunting as a marker for persistent long-term shunting was poor, whereas both patients with immediate grade III shunting had shunt persistence, indicating that immediate revision should be considered in such patients. Intraoperative epicardial ultrasound is valuable for the immediate exclusion of important residual shunting after ventricular septal defect closure. Maximal information is obtained when color flow mapping and contrast echocardiography are used in combination.

Thrombocytopenia: first symptom in a patient with dyskeratosis congenita.

A case of dyskeratosis congenita is reported. This rare hereditary disease usually has the following progression: ectodermal dystrophy (reticular skin pigmentation, nail dystrophy, leukokeratosis of mucosal membranes), appearing in the first decade, followed in about 50% of these patients by a hematopoietic disorder resembling Fanconi's anemia, usually developing in the second or third decade. Carcinomas may occur in leukokeratotic areas in the third, fourth, or fifth decade. This patient's clinical course is interesting because the thrombocytopenia developed as an isolated symptom at the age of 5 years and preceded the skin anomalies by three years. The diagnosis of dyskeratosis congenita was made only after an evolution of five years. The diagnosis of dyskeratosis congenita--although it is a rare disease--should be considered in every child first seen with aplastic anemia or thrombocytopenia.

Intraoperative ultrasonographic identification of coronary artery compression after an arterial switch procedure.

A case is reported of a neonate with transposition of the great arteries, undergoing an arterial switch operation, in whom the cause for postbypass cardiac failure was diagnosed by intraoperative epicardial echocardiography. Obvious regional dyskinesia was seen by two-dimensional echocardiography in the posterolateral segments of the left ventricle, supplied by the circumflex coronary artery. After the switch procedure, the reimplanted circumflex artery ran between the aorta and the pulmonary artery. Lifting the pulmonary artery off the circumflex artery resulted in immediate improvement of regional myocardial function, which could be monitored on-line with echocardiography. Thus compression of the circumflex by the pulmonary artery was the cause for cardiac failure. On the basis of the echocardiographic information, immediate and successful surgical revision was performed. Intraoperative epicardial echocardiography has a unique diagnostic potential in the case of cardiac failure after cardiopulmonary bypass.

Treatment of patients with myelodysplastic syndromes with allogeneic bone marrow transplantation from genotypically HLA-identical sibling and alternative donors.

Between December 1981 and March 1994, 24 patients with a myelodysplastic syndrome (MDS) underwent allogeneic bone marrow transplantation (BMT) for RA with trilineage dysplasia (n = 4), CMML (n = 1), RAEB (n = 4), RAEBt (n = 9) and AML following MDS (n = 6). Fifteen patients (two RAEB, seven RAEBt and six sAML) received chemotherapy before BMT resulting in complete remission in 10 patients (six RAEBt and four sAML) at the time of BMT. Sixteen marrow donors were genotypically HLA-identical siblings. Remaining donors were other family members (five) or unrelated donors (three). The status of the underlying disease at the time of conditioning was the major factor determining long-term survival. The disease-freed survival of RA patients and patients presenting with RAEB, RAEBt and AML but transplanted in complete remission, was respectively 50 and 60%. On the contrary, none of the nine high-risk MDS patients transplanted with persistent disease, survived. Outcome after transplantation with alternative donors was inferior with one long-term survivor, mainly related to the high incidence of severe acute GVHD and its accompanying infectious complications. Six patients relapsed resulting in an actuarial probability of relapse of 28%. Twelve patients died of transplant-related complications leading to a non-relapse mortality at 5 years of 50%. At present eight patients are alive and disease-free 20 to 132 months post-transplantation resulting in an actuarial 5-year disease-free survival of 40.7%. Our results suggest that allogeneic bone marrow transplantation is a feasible treatment option for patients with MDS. However, improvement in GVHD prophylaxis and supportive care to reduce transplant-treated mortality and improved relapse prevention are imperative.

A variant (2;13) translocation in rhabdomyosarcoma.

Cytogenetic analysis of a right buttock mass from a 5-year-old boy showed translocation between an inverted chromosome 1 and a chromosome 13 as the sole cytogenetic abnormality. The breakpoint 13q14 appears to be the same as in previously reported cases of rhabdomyosarcoma (mostly of the alveolar type), but does not show involvement of 2q37. We suggest that this translocation may be a variant of the classical t(2;13)(q37;q14) found in rhabdomyosarcoma.

5q- syndrome in a child.

A boy aged 8 years, 10 months presented with refractory anemia. Bone marrow investigation revealed monolobular megakaryocytes. Cytogenetic analysis showed a clonal abnormality: 46, XY, del(5)(q14q32). This is the youngest individual ever reported with this disorder. A year after diagnosis, while on treatment with human recombinant erythropoietin, the bone marrow showed an excess of blasts. No bone marrow donor could be found. Transformation to acute myelomonocytic leukemia occurred 3 months later. In spite of intensive chemotherapy, the child died of progressive disease with massive splenomegaly and jaundice. The case illustrates that the 5q- syndrome can occur de novo in children. The outcome in this child was poor, which may reflect a difference from the adult 5q- syndrome or may possibly be related to the erythropoietin the child received.

Cytogenetic investigations in childhood chronic myelocytic leukemia.

Cytogenetic studies were performed on 25 chronic myelogenous leukemia patients aged between 6 mo and 19 yr. Of these, 14 presented with the adult form and 11 with the juvenile form of the disease. In patients with the adult type, 12 of 14 had a Ph chromosome and additional anomalies appearing during blastic transformation. In patients with the juvenile form, 6 of 11 had a monosomy 7 and a short survival time (median 10 mo). Salient features of these patients, as well as a survey of the pertinent literature on the subject, are presented in this paper.

Anomalies of the long arm of chromosome 11 in human myelo- and lymphoproliferative disorders. I. Acute nonlymphocytic leukemia.

In a series of 365 consecutive ANLL cases of which 45.1% had abnormal karyotypes, 13 cases were detected with a structural abnormality of the long arm of chromosome 11. Besides one isochromosome 11q, there were six deletions and six translocations. Of these 12 patients, seven had acute monocytic leukemia (FAB-type M5), two had an M4, two had an M2, and one case of secondary leukemia had an M3-like disorder. Similar results with regard to the type of leukemia were obtained upon analysis of 41 cases of ANLL with an 11q anomaly described in the literature. This study confirms that a high proportion of acute monocytic leukemias and a lesser proportion of acute myelomonocytic leukemias are characterized by an 11q anomaly, mostly involving bands q22 and/or q23. Acute monocytic leukemia with an 11q structural anomaly appears to have a poor prognosis.

Non-endemic Burkitt's lymphoma in a patient with Bloom's syndrome.

Bloom's syndrome is an autosomal recessive disorder characterized by intrauterine growth retardation, typical physical signs, immunodeficiency and an increased risk of developing neoplasms at a young age, compared to the general population. Factors possibly involved in the pathogenesis of non-endemic Burkitt's lymphoma in a five year old girl with Bloom's syndrome are discussed. These include immunodeficiency, upregulated c-myc expression and an Epstein-Barr viral infection.

Prognostic value of dipyridamole sestamibi single-photon emission computed tomography and dipyridamole stress echocardiography for new cardiac events after an uncomplicated myocardial infarction.

A high-dose dipyridamole stress test (0.84 mg/kg in 6 minutes) with simultaneous sestamibi single-photon emission computed tomographic (SPECT) and echocardiographic imaging was performed in 89 patients before hospital discharge after an uncomplicated myocardial infarction. The aim of this study was to determine the prognostic value of these tests for new cardiac events and to compare the relative values of SPECT and echocardiography in a postinfarction dipyridamole stress test. Two years after infarction, nine patients (10%) had died, five patients (6%) had suffered a nonfatal reinfarction, and 14 patients (16%) had been readmitted to the hospital for a revascularization procedure. Cardiac death had occurred in 5 (10%) of 48 patients with a positive SPECT versus 4 (10%) of 41 with a negative SPECT (difference not significant) and in 6 (19%) of 31 with a positive echocardiogram versus 3 (5%) of 56 with a negative echocardiogram (p = 0.05). Cardiac death or reinfarction had occurred in 8 (17%) of 48 patients with a positive SPECT versus 6 (15%) of 41 with a negative SPECT (difference not significant) and in 6 (19%) of 31 with a positive echocardiogram versus 8 (14%) of 56 with a negative echocardiogram (difference not significant). Thus the predictive value of the dipyridamole stress test for new cardiac events after an uncomplicated myocardial infarction was limited, irrespective of the method used to detect ischemia. Reversible perfusion defects were identified more frequently than new wall motion abnormalities but did not predict late events. A positive dipyridamole echocardiogram was associated with a higher late mortality rate but did not predict other cardiac events.

Background correction in factor analysis of dynamic scintigraphic studies: necessity and implementation.

In factor analysis, structures are separated on the basis of their temporal behaviour, even if there is a partial overlap. Usually, the temporal behaviour of the system under study cannot be sampled in its true form due to a total overlap by the background. In the ROI (region of interest) method, background subtraction is used as a means to correct the problem. In factor analysis, this problem has been ignored for a long time. We prove that the factor analysis method gives incorrect results when there is a total overlap of a structure. By assuming a local homogeneity of the overlapping structure, we can greatly improve the solution found. Compared with the classical ROI method, our method is operator independent and organ specific.

Intraoperative ultrasound monitoring of banding of the pulmonary trunk: a new technique?

We report an intraoperative real-time echo/Doppler study of the hemodynamic effects of banding of the pulmonary trunk in complete transposition seven years after a neonatal Mustard procedure. The patient had developed severe right ventricular failure. To prepare the left ventricle for an arterial switch procedure, banding of the pulmonary trunk was performed. While tightening the band, we monitored the pressure drop produced by using real time continuous wave Doppler interrogation. After banding, we used combined M-mode and cross-sectional echocardiography to image the left changes induced in left and right ventricular dimensions, shape and function by the acute change in hemodynamics.

Lymphedema of the leg associated with rheumatoid arthritis.

A 14-year-old boy with a two year history of seronegative rheumatoid arthritis developed left leg lymphedema and subsequently a severe episode of lymphangitis. The diagnosis of "rheumatoid lymphedema" was confirmed by lymphscintigraphy and conventional lymphography. Treatment consisted of bedrest and antibiotic drugs. When the signs of inflammation had subsided, therapy with corticosteroids was started with improvement of both joint pain and leg swelling. Whereas lymphedema associated with rheumatoid arthritis has been described in the upper limb of adults, to our knowledge this is the first report of the coexistent condition in the lower leg of a child.

[Moyamoya. Diagnosis using MRI and NMR angiography]. / Moya-moya. Diagnostic par IRM et angiographie RMN.

A case of Moya-Moya disease confirmed by cerebral angiography in a 10-year-old girl is reported. Hypertrophic collateral circulation is easily visualized by MRI. MR angiography very accurately demonstrated the vascular obstruction and the collateral circulation. As MR angiography is not invasive, it promises to become a valuable alternative to conventional angiography in the diagnosis of Moya-Moya.

[Sudden death in young persons caused by arrhythmogenic right ventricular dysplasia]. / Plotselinge dood bij jonge mensen door aritmogene rechterventrikeldysplasie.

A previously healthy boy aged 14 developed persistent ventricular tachycardia while engaged in sports; ultrasonography revealed arrhythmogenic right ventricular dysplasia (ARVD). He was treated with a class III antiarrhythmic drug but nevertheless died 4 years later during recreational activities. An uncle of the boy was found to have died suddenly on a playing field, 25 years previously at the age of 20. In ARVD, fibrolipomatous areas in the right ventricle lead to dilations of the wall where (sometimes fatal) re-entrant tachycardias may develop. An autosomal dominant heredity with variable expression and penetrance is considered probable, while the genetic defect was located recently. Examination and, if necessary, pharmacotherapy of relatives of an ARVD patient may reduce the risk of a fatal arrhythmia.

[Transient erythroblastopenia in 4 children]. / Voorbijgaande erytroblastopenie bij 4 kinderen.

In four patients, all girls, aged 2, 3.5, 4 and 5 years, transient erythroblastopenia was diagnosed. The children were presented because of acute pallor. The haemoglobin levels were 2.8 to 5.0 mmol/l. After 3 weeks all patients had recovered or were recovering with increasing haemoglobin values. Three of the four patients needed one blood transfusion. In two patients there was evidence of a parvovirus B19 infection. Transient erythroblastopenia is mostly seen in patients aged 1-4 years. Most cases are postinfectious and there is evidence that human parvovirus B19 is responsible for many cases. In the very young child the differential diagnosis from Blackfan-Diamond anaemia may be very difficult.