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Biomedical subjects

R Mertens

Publications and source records attributed to R Mertens.

At least 73 records · Page 4Linked to original sources
PubMed1989

Abscisic acid is involved in the wound-induced expression of the proteinase inhibitor II gene in potato and tomato.

Plants respond to wounding or pathogen attack by a variety of biochemical reactions, involving in some instances gene activation in tissues far apart from the actual site of wounding or pathogen invasion. One of the best analyzed examples for such a systemic reaction is the wound-induced expression of proteinase inhibitor genes in tomato and potato leaves. Local wounding of potato or tomato plants results in the accumulation of proteinase inhibitors I and II throughout the aerial part of the plant. In contrast to wild-type plants, abscisic acid-deficient mutants of potato (droopy) and tomato (sit) show a drastically reduced induction of these genes in response to plant wounding. High levels of proteinase inhibitor II gene expression are obtained in mutant and wild-type plants upon exogenous application of abscisic acid. Measurements of the endogenous abscisic acid levels in wild-type plants show that wounding results in increased levels of this phytohormone in wounded and nonwounded systemically induced leaves. Thus these results show that the plant hormone abscisic acid is involved in the wound-induced activation of the proteinase inhibitor II gene. Furthermore, they are compatible with a model assuming this hormone to be the actual mediator of the systemic wound response.

Journal Article↗
PubMed1989

[Value of preoperative colonoscopy in colon-rectal neoplasms].

The surgical approach to treat colo-rectal carcinoma is usually based on the findings of barium enema. In 102 patients we reviewed the yield of pre-operative colonoscopy. Barium enema revealed the cancer in 76 of 84 patients (91%), whereas colonoscopy did so in 96 of 102 subjects (94%). In addition, 5 associated cancerous lesions were demonstrated by colonoscopy and none by barium enema. Associated benign lesions were seen in 14 patients. In 5 patients the surgical plan based on the barium enema was modified by the findings at colonoscopy. Eight false negatives to barium enema were correctly diagnosed by colonoscopy. We conclude that colonoscopy yields valuable information, beyond that of barium enema, in patients with colo-rectal cancer.

Adult↗
PubMed1988

Water-stress-induced changes in the abscisic acid content of guard cells and other cells of Vicia faba L. leaves as determined by enzyme-amplified immunoassay.

A highly sensitive, solid-phase, enzyme-amplified immunoassay for the plant growth regulator (+)-abscisic acid (ABA) was developed. The assay sensitivity (0.2-10 fmol) was sufficient for analyzing free ABA in homogeneous tissue samples dissected from Vicia faba L. leaves. Eight hours after detached leaves had been desiccated to 10% loss of fresh weight, the bulk leaf ABA content increased from </=0.2 to 6.2 ng.(mg dry weight)(-1). Epidermal tissue, spongy parenchyma cells, and palisade parenchyma cells from this water-stressed leaf had the following ABA contents, respectively: 4.8, 9.4, and 9.0 ng.(mg dry weight)(-1). Guard cells, which respond to exogenous ABA by losing solutes and volume, were also assayed. When they were dissected from control (fully hydrated) leaves, their ABA content was approximately 0.7 fg.(cell pair)(-1) [[unk]0.2 ng.(mg dry weight)(-1)]. In contrast, the ABA content of guard cells of water-stressed leaves was approximately 17.7 fg.(cell pair)(-1). These results indicate that ABA accumulation in a highly stressed V. faba leaflet is generalized; guard cells contain only 0.15% of bulk leaf ABA. The time course for loss of ABA from guard cells of a floating epidermal peel was studied. There was little loss within 30 min, but after 4 hr, the ABA content was only 17% of the original value. These results indicate that the bulk of guard cell ABA is not readily diffusible (i.e., probably not apoplastic). The results also indicate that common laboratory procedures results in lowered guard cell ABA content.

Journal Article↗
PubMed1987

Acute leukemia with chromosome translocation (4;11): 7 new patients and analysis of 71 cases.

Clinical and laboratory features of seven patients with acute leukemia associated with the (4;11) chromosome translocation are presented. Leukemic blasts of these patients showed lymphoid morphology in 6 (although 1 was treated for monoblastic leukemia 3 years earlier) and monocytoid morphology in 1, were positive for TdT and HD 37 (CD 19) in 6 patients, whereas weak expression of CALLA was seen in only 1 patient and T-lineage-associated antigens in none. Leukemic blasts from four patients showed the simultaneous expression of B-lymphoid and myeloid antigens, suggesting leukemogenesis in a very early multipotent progenitor cell. In 2 patients an isochromosome of the long arm of No. 7 chromosome was found in the leukemic karyotypes in addition to t (4; 11) (q 21; q 23); in one instance present at diagnosis, in the other one occurring at relapse. In one other patient leukemia karyotype also demonstrated trisomy 8. Leukemic cells of three patients were investigated by molecular genetics and demonstrated immunoglobulin gene rearrangements for the Ig heavy chain sequences but not for the light chain constant regions and T cell receptor sequences. All patients were treated by intensive chemotherapy. Four of the 7 patients are in continuous complete remission. The longest event-free survival time (over 2 1/2 years) was seen in one patient who had also DOWN-syndrome. Including these 7 patients a clinical analysis of 71 patients with t (4; 11) acute leukemia was made, emphasizing the following characteristics at diagnosis: female sex (62%), age under 2 years (49%), leukocyte count over 100 X 10(9)/1 (61%), splenomegaly (80%), CNS-disease (11%). Survival of over 2 years was reported in less than 15% of the patients. It remains to be seen if risk-adapted treatment can alter the course of this early B-precursor acute leukemia with hitherto very bad prognosis.

Acute Disease↗
PubMed1987

The national prevalence survey of nosocomial infections in Belgium, 1984.

A national one-day prevalence survey of nosocomial infections was carried out in March 1984 in 106 Belgian acute-care hospitals involving 8723 patients of whom 6130 had undergone surgery. Three infections were studied: surgical wound infection, bacteraemia and urinary-tract infection. One or more of these three infections was recorded in 9.3% of all patients and in 11.8% of surgical patients. Prevalences increased with increasing duration of hospital stay and with higher ages, but the association of HAI with age was no longer significant after correction for duration of hospital stay. Prevalences varied considerably in different specialties. After adjustment for age and duration of stay, there was no association between perioperative antibiotic prophylaxis and the prevalence of the infections studied, but bias due to selection of higher risk patients in the antibiotic group was probable. Larger hospitals had a higher overall prevalence, but populations differed according to the size of the hospital. Bacteraemia was strongly associated with the presence of an intravenous catheter, and urinary-tract infection with a urinary catheter.

Adult↗
PubMed1987

Tool for validation of the network of sentinel general practitioners in the Belgian health care system.

Morbidity registration by a network of sentinel general practitioners (SGPs) in Belgium raises a number of problems related to possible biases in the network procedure, such as unequal geographical distribution, non-participation of a segment of the target population of practitioners and difficulties in the estimation of the denominator population at risk for the health problems under study. Through the application of two hierarchical clustering procedures, the initial number of 43 districts in the country has been reduced to 15 homogeneous district clusters. These represent the new geographical framework from which the geographical spread of the network is checked. This network is subsequently corrected for such socio-demographic parameters as age, sex and occupation in order to match more closely the total population of Belgian general practitioners (GPs). The population covered by the network is estimated on the basis of the annual number of patient contacts. Application of the described procedures should result in a network allowing valid estimations for a number of health issues as seen by Belgian GPs.

Adult↗
PubMed1986

Treatment of childhood idiopathic thrombocytopenic purpura with Rhesus antibodies (anti-D).

We have recently reported that a rise of platelet numbers in ITP can be induced by blockade of the RES with antibody-coated red blood cells. We now present a collaborative study in which 15 Rhesus-positive children with ITP (nine boys and six girls aged 1-15 years) were treated with low-dose anti-D. Ten patients had chronic ITP (duration 6-47 months), five had acute ITP. Doses of 28-50 micrograms anti-D/kg bodyweight per course were given intravenously. In all patients clinical signs of bleeding ceased and platelet counts were elevated. An excellent, good or fair response with platelet increments of greater than 100, 50-100, or 20-50 X 10(9)/l, respectively, was observed in 19, 7, and 12 out of 45 courses in chronic ITP, and in 4, 1, and 2 out of 8 courses in acute ITP. The platelet increase (greater than 40 X 10(9)/l) persisted for 10 to over 360 days in chronic ITP. There were no untoward side reactions. Haemoglobin values remained stable in all patients but laboratory signs of mild, compensated haemolysis ensued. The direct antiglobulin test became positive in all cases due to anti-D IgG. Previous therapy of patients with chronic ITP included high-dose immunoglobulins and prednisone. These regimens were both effective but remissions were short. We conclude that anti-D therapy is an effective and safe form of treatment in childhood ITP.

Adolescent↗
PubMed1983

[Typical skeletal changes in metastatic neuroblastoma].

Compared with other solid tumours in childhood, neuroblastomas show a marked tendency to metastasise to the skeleton. The differentiation of these lesions from inflammatory and other malignant bone lesions in this age group is often difficult. The radiological findings in ten patients with metastasising and histologically confirmed neuroblastomas have been reviewed and the typical appearances in the skeleton are described. The most important features in the differential diagnosis are discussed and the significance of bone changes in the diagnosis of neuroblastoma have been evaluated.

Bone Neoplasms↗
PubMed1983

Evaluation of a radioimmunoassay for estradiol in unextracted serum.

We describe the performance of a commercial (Steranti/EIR) RIA reagent kit for measuring 17 beta-estradiol directly in serum. Day-to-day precision data for control sera were as follows: mean = 102.8 ng/L, CV = 6.8%, n = 20; mean = 231.1 ng/L, CV = 5.3%, n = 21; mean = 747.7 ng/L, CV = 9.4%, n = 21. Analytical recovery of added estradiol from seven different serum pools from men, to which three different concentrations of estradiol had been added, was (mean +/- SD): 98.6 +/- 7.0% at 107.5 ng/L added; 98.8 +/- 4.7% at 322.5 ng/L added; 108.2 +/- 4.8% at 645 ng/L added. Overall recovery of estradiol in these experiments (mean +/- SD for 21 determinations) averaged 101.9 +/- 7.0%. Assay of 32 serum specimens from women by both the direct (y) and an extraction method (x) gave the following linear regression statistics: y = 1.12x - 1.3, r = 0.998, Sy/x = 30.2 ng/L, mean y = 438.2 ng/L, mean x = 391.4 ng/L. Hemoglobin, bilirubin, and moderate lipemia do not interfere. Sensitivity of the direct assay was 2.6 ng/L. Compared with the extraction assay, the direct estradiol assay has advantages of speed and simplicity.

Estradiol↗
PubMedDate not supplied

CT-guided percutaneous large-bore biopsies in benign and malignant pediatric lesions.

Thirty-nine consecutive pediatric patients underwent large-bore biopsies of 41 lesions under computed tomography (CT) guidance; general anesthesia was not required. Adequate material was obtained in all patients. There were no false-negative or false-positive results. Typing accuracy was 100% in malignant disease and 92% in benign lesions. No significant complications occurred. Percutaneous large-bore biopsy is a safe, reliable, and time-saving method that obviates the need for open surgery and general anesthesia in the diagnosis of primarily non-resectable lesions, or lesions that do not require resection. Another major advantage over open surgery in malignant disease is the absence of delay in starting urgently needed chemotherapy.

Adolescent↗
PubMedDate not supplied

Transient myeloproliferative disorder with 11q23 aberration in two neonates with Down syndrome.

Infants with Down syndrome may develop a transient myeloproliferative disorder (TMD) with the features of acute leukemia but resolving in a spontaneous remission. Chromosomal aberrations in addition to trisomy 21 have only rarely been described. In many cases of infant acute leukemia band q23 of chromosome 11 is involved in nonrandom translocations, often resulting in a rearrangement of the ALL-1 (MLL, HRX, HTRX 1) gene. Generally, this translocation carries a bad prognosis. We describe two newborn girls with Down syndrome and TMD in whom the constitutional trisomy 21 was combined with an acquired abnormality of chromosome 11. During the TMD the morphological and immunologic features were consistent with those of megakaryoblastic leukemia. The chromosome 11 abnormalities were del(ll)(q23), but rearrangements of the ALL-1 gene were not found. Our patients had remissions that occurred spontaneously or after a mild chemotherapy. The important finding is that additional chromosomal changes may occur during TMD in Down syndrome. The fact that the abnormality was in region 11q23 raises the question of whether the risk for developing leukemia is increased under these conditions.

Chromosome Aberrations↗
PubMedDate not supplied

[Combined treatment of nasopharyngeal cancer in children and adolescents--concept of a study].

Nasopharyngeal carcinomas (NPCs) are malignant tumors which exhibit a wide disparity in their age, racial, and geographic incidence. In parts of Africa NPCs account for 10% to 20% of childhood malignancies. In USA and Europe, the NCP is an uncommon tumor (0.2% of all malignancies) and amounts to only 1% to 2% of childhood malignancies. Etiology and pathogenesis are closely related to an infection with Epstein-Barr Virus (EBV) and the EBV genome was detected in tumor tissues. Children with NPC differ from their adult counterparts in having a closer association with Epstein-Barr-Virus-Infections. The classical lymphoepithelial carcinomas (Cologne type II-type III) have been found in young patients. Clinically, the disease is aggressive, characterised by frequent metastases in bone and lung. These carcinomas are associated with significantly elevated anti-EBV-titers. The prognosis of children with advanced NPC is poor with a 5-year survival rate between 20-30%. Radiotherapy is the treatment of choice in NPC which has provided an improvement in local tumor control in recent years. Human fibroblast interferon is an active agent in recurrent NPC. Seven children have been treated with IFN-beta, (6 with human und 1 with recombinant IFN-beta) as an adjuvant therapy in doses of 10(5) U/kg body weight three times a week for half a year. All patients received radiotherapy to primary site and had advanced stages (III-IV) at presentation. The patients' age ranged from 14-19 years at diagnosis. Six are still in CR (RFS are 10, 8, 8, 7, 6 and 1.5 years) and one patient relapsed after 18 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗