Functional antagonism of the Polycomb-Group genes eed and Bmi1 in hemopoietic cell proliferation

The murine Polycomb-Group (PcG) proteins Eed and Bmi1 govern axial patterning during embryonic development by segment-specific repression of Hox gene expression. The two proteins engage in distinct multimeric complexes that are thought to use a common molecular mechanism to render the regulatory regions of Hox and other downstream target genes inaccessible to transcriptional activators. Beyond axial patterning, Bmi1 is also involved in hemopoiesis because a loss-of-function allele causes a profound decrease in bone marrow progenitor cells. Here, evidence is presented that is consistent with an antagonistic function of eed and Bmi1 in hemopoietic cell proliferation. Heterozygosity for an eed null allele causes marked myelo- and lymphoproliferative defects, indicating that eed is involved in the negative regulation of the pool size of lymphoid and myeloid progenitor cells. This antiproliferative function of eed does not appear to be mediated by Hox genes or the tumor suppressor locus p16(INK4a)/p19(ARF) because expression of these genes was not altered in eed mutants. Intercross experiments between eed and Bmi1 mutant mice revealed that Bmi1 is epistatic to eed in the control of primitive bone marrow cell proliferation. However, the genetic interaction between the two genes is cell-type specific as the presence of one or two mutant alleles of eed trans-complements the Bmi1-deficiency in pre-B bone marrow cells. These studies thus suggest that hemopoietic cell proliferation is regulated by the relative contribution of repressive (Eed-containing) and enhancing (Bmi1-containing) PcG gene complexes.

Synthesis and cytostatic activities of didemnin derivatives

The highly cytostatic didemnins contain a 23-membered cyclopeptolide with a side chain attached to the backbone through the amine group of threonine. Thirty-six derivatives varying the side chain were prepared, but only compounds with D-MeLeu attached to threonine show remarkable biological activities. To protect the macrocycle from degradation by lipases the two ester bonds were replaced successively by amide bonds. Although these variations have a major effect on the conformation and rigidity of the ring, the compound which contains exclusively amide bonds is highly active, equivalent to acetyl-didemnin A.

Valuing gerontology nursing

It is time the specialist skills required in gerontology nursing were recognised: they have been underrated and undervalued for too long. This and the following article mark 1999 as the International Year of Older Persons.

The murine Polycomb-group gene eed and its human orthologue: functional implications of evolutionary conservation

Similar to Drosophila, murine Polycomb-group (PcG) genes regulate anterior-posterior patterning of segmented axial structures by transcriptional repression of homeotic gene expression. The murine PcG gene eed (embryonic ectoderm development) encodes a 441-amino-acid protein with five WD motifs which, except for the amino terminus, is highly homologous to Drosophila ESC (Extra Sex Combs). Here, sequence and expression analysis as well as chromosomal mapping of the human orthologue of eed is described. Absolute conservation of the human eed protein along with significant divergence at the nucleotide level reveals functional constraints operating on all residues. The human orthologue appears to be ubiquitously expressed and maps to chromsome 11q14.2-q22.3. Using the first WD motif of the beta-subunit of the bovine G protein as a structural reference, the predicted locations of two previously identified eed point mutations (A. Schumacher et al., 1996, Nature 383: 250-253) are also reported herein. The proline substitution (L196P) in the second WD motif of the l7Rn5(3354SB) null allele maps to the internal core of the inner end of the beta-propeller blade and is likely to disrupt protein folding. In contrast, the asparagine substitution (I193N) in the second WD motif of the hypomorphic l7Rn5(1989SB) allele maps onto the surface of the beta-propeller blade near the central cavity and may affect surface interactions without compromising propeller packing. These results illustrate the critical importance of all residues for eed function in mammals and support a model whereby the amino terminus might implement function(s) related to embryonic development in higher organisms.

Ex vivo breast cancer cell purging by adenovirus-mediated cytosine deaminase gene transfer and short-term incubation with 5-fluorocytosine completely prevents tumor growth after transplantation

Peripheral blood progenitor harvests of breast cancer patients are contaminated with tumor cells, suggesting a potential role for these cells in the relapse after high-dose chemotherapy. Whereas physical purging methods do not eliminate contaminating tumor cells completely, pharmacological purging, although highly efficient, is hampered by a strong nonspecific toxicity toward hematopoietic progenitor cells. Taking advantage of the high efficiency of adenovirus-mediated gene transfer to epithelial cells, we selectively loaded breast cancer cells in vitro with a cytotoxic drug by gene transfer of the prodrug-converting enzyme cytosine deaminase (AdCMV.CD) and 5-fluorocytosine (5-FC). Despite the low dose of vector administered, limited exposure to 5-FC, and transplantation only of viable tumor cells into SCID mice, all animals that received cells treated in vitro with AdCMV.CD plus 5-FC were completely free of tumor development. These data show that the selective loading of tumor cells with AdCMV.CD/5-FC might be useful for purging of autografts.

[Vascular diameter and resistance indices in normal fetuses with a single umbilical artery]

OBJECTIVE

This study was undertaken to investigate the vascular-adaptive mechanism of fetuses with a single umbilical artery (SUA) and without structural anatomical abnormalities.

METHODS

A cohort study including fetuses with the diagnosis of SUA at routine ultrasonographic examination was designed. The diagnosis of SUA was confirmed by color Doppler imaging and by histological examination of the umbilical cord after delivery. The inner artery and vein diameters were measured and the resistance-index (RI) of the SUA was calculated.

RESULTS

Eleven fetuses were studied. The artery and vein diameters were 2 standard deviations above the mean, when plotted in reference ranges, in 12 out of 17 (70.5%) and 8 out of 16 (50%) measurements, respectively. The RI-values were below the 5th and 50th percentile in 50% (6/12) and 75% (9/12) of the measurements, respectively.

CONCLUSION

A dilatation of the single artery occurs to reduce the impedance in this vessel and to preserve a sufficient feto-placental blood flow. In addition the umbilical vein also increases in size.

Contribution to the synthesis of aureobasidin A. Synthesis of cyclopeptolides containing the sequence leucyl-N-methyl-beta-hydroxyvalyl-(2R)-oxy-(3R)-methyl-pentanoi c acid

The efficient antimycotic agent aureobasidin A, isolated from the culture broth of Aureobasidium pullulans R 106, and the [(R)-Pro9]-aureobasidin A were prepared starting from benzyl N-Boc-N-methyl-(S)-beta-triethylsiloxyvalinate, the synthesis of which is described here. The easy accessibility of the tripeptolide benzyl Boc-leucyl-N-methyl-beta-hydroxyvalyl-(2R)-oxy-(3R)-methylpentanoa te [Boc-Leu-HOMeVal-(R)-HMP-OBn] facilitates the construction of the cyclopeptolides 28, 34, 45 and 47. The peptide bonds of the N-methylamino acids were formed with the help of O-(7-azabenzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophophate. The rings of [(R)-Pro9]-aureobasidin A and of cyclopeptolides 28, 34, 45 and 47 were closed by way of pentafluorophenyl esters. The ring of aureobasidin A could only be formed with bromo-tris-pyrrolidinophosphonium hexafluorophosphate.

Interaction of mouse polycomb-group (Pc-G) proteins Enx1 and Enx2 with Eed: indication for separate Pc-G complexes

The Polycomb group (Pc-G) constitutes an important, functionally conserved group of proteins, required to stably maintain inactive homeobox genes repressed during development. Drosophila extra sex combs (esc) and its mammalian homolog embryonic ectoderm development (eed) are special Pc-G members, in that they are required early during development when Pc-G repression is initiated, a process that is still poorly understood. To get insight in the molecular function of Eed, we searched for Eed-interacting proteins, using the yeast two-hybrid method. Here we describe the specific in vivo binding of Eed to Enx1 and Enx2, two mammalian homologs of the essential Drosophila Pc-G gene Enhancer-of-zeste [E(z)]. No direct biochemical interactions were found between Eed/Enx and a previously characterized mouse Pc-G protein complex, containing several mouse Pc-G proteins including mouse polyhomeotic (Mph1). This suggests that different Pc-G complexes with distinct functions may exist. However, partial colocalization of Enx1 and Mph1 to subnuclear domains may point to more transient interactions between these complexes, in support of a bridging role for Enx1.

DNA ploidy abnormalities in rabbit preimplantation embryos are not increased by conditions associated with in vitro culture

Possible adverse effects of in vitro culture-associated physical factors were studied in 3- and 4-day-old rabbit embryos. Laboratory conditions were mimicked by exposure to visible light (320-740 nm, 1600 lx) or decreased temperature (22 +/- 1 degree C). Embryos were exposed for a 24-hr period followed by either immediate evaluation or an additional 24 hr of standard in vitro culture (darkness, 37 degrees C) and evaluation thereafter. Effects were assayed by cytophotometric measurement of the DNA content in Feulgen-stained cell nuclei and by cell number. The incidence of DNA aneuploid embryos and DNA aneuploid cell nuclei per embryo, as well as the average nuclear DNA content, was not significantly different between exposed embryos and controls. Both in vitro culture and reduced temperature caused a decrease in cell number. The temperature-induced cell number decrease was reversible within 24 hr after return to 37 degrees C. These results demonstrate that physical factors associated with in vitro culture do not increase DNA ploidy abnormalities in cultured preimplantation embryos.

Quality of life in adult patients with acute myeloid leukemia receiving intensive and prolonged chemotherapy -- a longitudinal study

Intensification of treatment for acute myeloid leukemia (AML) in adult patients resulted in a substantial improvement in long-term prognosis. Therefore, the assessment of quality of life (QL) of patients undergoing treatment is of growing interest. This study was designed to evaluate QL in patients with AML treated according to the protocol of the German AML-Cooperative Group (Münster, Germany). The EORTC QLQ-C 30 questionnaire was used to analyze QL throughout therapy, evaluating defined specific parameters at 12 different time-points. Sixty-one patients were recruited within the first 30 months of the study. Those 28 patients who have completed the course of inpatient treatment (n=28) are evaluated for changes in the conceptually distinct QL domains: Physical Functioning (P<0.001), Role Functioning (P=0.001), Emotional Functioning (P < 0.001) and Social Functioning (P=0.007) improve significantly from beginning of chemotherapy to the end of inpatient treatment. Individual assessment of Global Health Status and Subjective QL improves significantly over the same time (P< 0.001). At the end of inpatient treatment patients suffer significantly less from fatigue, nausea/emesis, loss of appetite and sleep disturbance (P < 0.001). Although most patients with AML eventually relapse, the evaluation of QL in patients undergoing treatment shows that subjective benefit outweighs the adverse effects of antileukemic therapy.

Elevated serum cyclophilin levels in patients with severe sepsis

Several cytokines are considered to be important mediators in the pathophysiology of sepsis. Cyclophilins (Cyps), the main binding proteins for the immunosuppressive drug cyclosporine A, have been suggested to function as cytokines. This study was conducted to determine (i) if serum Cyp levels were elevated in critically ill patients suffering from either sepsis or other life-threatening diseases and (ii) if so, whether there was an association between Cyp levels and a certain diagnosis and/or outcome. Serum samples of 45 patients (22 severe sepsis, 23 other diagnoses) and 17 healthy controls were prospectively analyzed by an enzymatic assay using the ability of cyclophilins to catalyze cis/trans isomerisation of peptidylprolyl-peptide bonds (PPIase activity). In addition, western blotting was applied to differentiate both isoforms. PPIase activity was significantly higher in patients with severe sepsis than in patients with other diagnoses (P = 0.004) or in healthy subjects (P = 0.001). There was no difference between healthy subjects and other critically ill patients (P = 0.067). Elevated PPIase activity was associated with high mortality (P = 0.03). It is concluded that Cyps might play a role, probably as mediators in the pathophysiology of sepsis or as symptoms of diagnostic value.

The effect of drug therapy on the perceived symptom and ADL experiences of narcoleptics

Medications for the treatment of narcolepsy consist of central nervous system (CNS) stimulants to control the somnolent symptoms and tricyclic antidepressants to control the rapid-eye-movement (REM) sleep related symptoms. Anecdotal information suggested that many narcoleptics perceive their symptoms, particularly their sleepiness, to be poorly controlled despite taking medication. This study was a secondary analysis which examined if drug therapy made a difference in the perceived symptom experience and ability to perform daily living activities (ADLs) as reported by narcoleptics. No significant association was found between CNS stimulant or tricyclic antidepressant drug therapy and the subjective ratings of narcoleptic symptoms, nor with the perceived ability to perform ADLs. While this study did not examine symptom ratings on and off drug therapy, these findings do suggest that narcoleptics may have to utilize behavioral strategies with their medication regimens to effectively cope with narcolepsy's adverse effects on daily life.

EMG activity of medial and lateral hamstrings at three positions of tibial rotation during low-force isometric knee flexion contractions

The purpose of this investigation was to determine how the position of tibial rotation effects the EMG activity of the medial and lateral hamstrings during low-force isometric knee flexion contractions. Forty-five subjects (ages 18-35) with no history of lower extremity injury or disease volunteered for this study. While lying prone, and with surface EMG electrodes secured to the bellies of their right medial (semitendinous and semimembranosus) and lateral (long head of the biceps femoris) hamstring muscles, each subject held the knee in 45° of flexion for 8 s against 5% of their body weight. This was performed three times in each of the positions of neutral tibial rotation, external tibial rotation, and internal tibial rotation. The root-mean-square (RMS) of the EMG activity from these muscles was determined for each of the contractions. A repeated measures ANOVA was used to compare the RMS values of the two muscle groups in the three positions. The average RMS values (in microvolts [mV]) obtained were (means and standard deviation): medial hamstrings in external rotation: 50.74 ± 23.11; in neutral: 65.57 ± 25.35; in internal rotation: 70.73 ± 31.86; lateral hamstrings in external rotation: 66.08 ± 46.99; in neutral: 46.18 ± 39.34; in internal rotation: 27.68 ± 17.86. A statistically significant interaction was found between tibial rotation and hamstring muscle (p < 0.0001). These results are consistent with the presumed function of these muscles in that EMG activity in the medial hamstrings increased when the tibia was rotated internally, whereas the lateral hamstring EMG activity increased when the tibia was rotated externally.

[Quality of life and coping with illness in patients with acute myeloid leukemia]

Advances in chemotherapy significantly prolong survival of patients with acute myeloid leukemia (AML) and may cure a significant percentage of patients. Therefore, the assessment of quality of life (QL) of patients undergoing chemotherapy is of growing interest. This study was designed to evaluate QL in patients with AML treated according to the protocol of the German AML-Cooperative Group (Münster, FRG). Based on conceptual, methodological and practical criteria, the EORTC-QLQ C 30 questionnaire was used. In addition, patients' coping strategies were assessed by the FQCI. Patients' individual perception of their disease and therapy was evaluated by a semi-structured interview. Currently, 61 patients are enrolled in the protocol. For those patients having completed the course of inpatient treatment, individual assessment of Global Health Status and Subjective QL improves significantly. The content analysis of the interviews shows to what extent aspects of the inpatient setting influence patients' QL. Although only a minority of patients with AML remain in continuous complete remission, the evaluation of QL in patients undergoing treatment shows that subjective benefit outweighs the effects of antileukemic therapy.

[Diagnosis of recurrence of a glomus carotid artery tumor by somatostatin receptor scintigraphy]

Glomus caroticum tumours belong to the non chromaffine paragangliomas. As the incidence is very poor with 1% in the collective of a vascular-surgery department, the correct diagnosis is preoperatively only found in 10-20% of the cases. The early detection of primary- or recurrence-tumour is important for the surgical proceedings. With advanced tumour-stage, i.e. with involvement of the carotid artery in the tumour-process, the perioperative mortality increases. Furthermore nerve lesions following surgical tumour-resection as a complication are more frequent. This case-report point out the importance of the somatostatin-receptor-scintigraphy in the differentiation of glomus caroticum tumour-recurrence and postoperative scar. In our patient the suspicion of tumour-recurrence came up already 2 years ago, but could not be verified by MRT and angiography.

Solid-state mid-infrared laser facilitated coronary angioplasty: clinical and quantitative coronary angiographic results in 112 patients

BACKGROUND AND OBJECTIVE

Holmium:YAG is a solid-state, investigational coronary laser device. Preliminary reports indicate the clinical potential for this laser; however, its safety and efficacy in a single center experience have not yet been reported and analyzed in detail.

STUDY DESIGN, PATIENTS, AND METHODS

One hundred and twelve consecutive symptomatic patients underwent percutaneous holmium:YAG laser (2.1 micron wavelength, 250-600 mJ/pulse, 5 Hz) facilitated coronary angioplasty. Sixty-six patients (Gr 1) had 74 thrombotic lesions, and 46 patients (Gr 2) had 55 thrombus-free stenoses.

RESULTS

Overall laser success was achieved in 120 out of 129 lesions (93%), with 95% subsequent balloon angioplasty success. Laser and clinical successes among the two groups were similar. By quantitative coronary angiography, reduction in the percent diameter stenosis (mean +/- SD) was similar (79 +/- 16% to 37 +/- 14% vs. 73 +/- 16% to 37 +/- 11.5%; P = NS) in both groups. However, minimal luminal diameter improved significantly more in Gr 1 patients, (0.7 +/- 0.5 mm to 2.0 +/- 0.5 mm, vs. 0.9 +/- 0.4 mm to 1.8 +/- 0.4 mm, P = 0.03). Angiographic and clinical complications were similar in patients with thrombus and without thrombus. No death, perforation, or Q-wave infarction occurred in the catheterization laboratory in either group. In-hospital mortality occurred in two patients from cardiac causes unrelated to the laser application. Of the 98 patients who reached the 6 month anniversary, 76 (77%) remained asymptomatic. The restenosis rate among the patients who underwent repeat angiography was 50%.

CONCLUSIONS

Solid-state, mid-infrared laser can be safely and successfully applied to symptomatic patients with thrombotic and nonthrombotic lesions. Similar to other debulking devices, the effectiveness of this laser in yielding long-term patency has not been proved.

Laser-assisted coronary angioplasty in patients with severely depressed left ventricular function: quantitative coronary angiography and clinical results

Laser-assisted coronary angioplasty can be successfully applied to lesions not ideal for balloon angioplasty. Patients with severely impaired left ventricular (LV) function and complex coronary artery stenoses who call for percutaneous revascularization are considered a high risk group for balloon angioplasty. In order to determine the feasibility, safety, and acute clinical outcome of a solid state, pulsed wave, mid-infrared (2.1 micron) laser facilitated angioplasty in these patients, data from 112 patients with 129 lesions were analyzed. Patients were identified according to angiographic LV function; group I included 22 patients with left ventricular ejection fraction (LVEF) < or = 40% (mean = 25% +/- 10%) and group II included 90 patients with LVEF > or = 40% (mean = 58% +/- 8%). No difference in age, gender, diabetes, hypertension, tobacco use, history of previous coronary artery bypass surgery (CABGS) or percutaneous transluminal coronary angioplasty was registered between the two groups. Multivessel disease, previous myocardial infarction (MI), and severe angina were more prevalent among group I patients (P = 0.03). No difference was found in lesion location, complexity, length, or calcification between the two groups; although group I had more eccentric lesions. Both groups were treated with the same laser energy level followed by adjunctive balloon angioplasty. One hundred percent procedural success was obtained in group I versus 93% in group II (P = NS). By Q.C.A. (independent core lab), minimal luminol diameter increased in group I from 0.9 +/- 0.5 mm preprocedure to 2.0 +/- 0.5, as compared to 0.8 +/- 0.5 mm to 1.9 +/- 0.5 mm (P = NS) in group II. Stenosis severity improved from 69% +/- 16% preprocedure to 37% +/- 13% postprocedure in group I, as compared to improvement from 78% +/- 16% to 37% +/- 12.7% in group II (P = NS). Overall complication rate was remarkably low, with no death or perforation in either group; emergency CABGS 0% in group I and 1.1% in group II; dissections 4.5% in group I and 8.8% in group II. There was no significant difference in complication rate between the two groups. The results of this study suggest that holmium:YAG laser facilitated coronary angioplasty can be safely performed in patients with severe LV dysfunction, achieving a remarkably high procedural success and low complication rate.

[Intravenous leiomyomatosis]

A 49-year-old woman presented with a uterine tumour with solid and cystic parts. Extension of the tumour into the broad ligament was noted at the operation with wormlike plugs of tumour within the veins. The histological diagnosis of intravenous leiomyomatosis was evident. The disease turned out to be far advanced: a long continuous intraluminal mass extending from the iliac veins to the right ventricle made a second operation with thoracotomy and laparotomy mandatory. Postoperative follow-up showed so far, 1.5 years after operation, no evidence of recurrence. Intravenous leiomyomatosis is a very uncommon finding. Though it is histologically a benign smooth-muscle tumour, the biological behaviour with intravenous growth which may involve the right side of the heart, is quite aggressive. About 100 cases were reported in the literature; in no case could the diagnosis be made before surgery.

[Hemoperitoneum due to coitus without vaginal lesions]

A 27-year-old female patient presented in our clinic 14 hours after onset of acute lower abdominal pain during sexual intercourse. Sonography showed ascites around the uterus and structures suspected to be clotted blood. Diagnostic laparoscopy showed in the abdomen about 400 ml of clotted blood: sources of bleeding were small injuries of the left sacro-uterine ligament. Therapy was not necessary, except careful rinsing since hemostasis was already complete. It is important to consider abdominal injuries in cases of abdominal pain after sexual intercourse, even if vulvar or vaginal injuries are absent.

Physical localization of eed: a region of mouse chromosome 7 required for gastrulation

In the mouse, the embryonic ectoderm development (eed) region is defined by deletions encompassing the albino (c) locus of chromosome 7. The region is located 1-2 cM distal to the c locus and was of undetermined size. Embryos homozygous for deletions removing eed display defects in axial organization during gastrulation. Two loci, identified by chemical mutagenesis, are known to map within the eed interval. One, l7Rn5, probably represents the gene required for gastrulation. The second, l7Rn6, is required for survival after birth. fit1, a third locus identified by chemical mutagenesis, maps distal to the eed interval and is also required for survival after birth. A 900-kb YAC contig has been constructed, and deletion breakpoints defining the limits of the regions containing these loci have been localized. Their positions place the eed region within a maximum 150-kb interval at the proximal end of the contig, while fit1 maps to a 360-kb interval within the middle of the contig. Several clusters of rare-cutting restriction sites map within these regions and represent potential locations of candidate genes.