Microtubules are required for centrosome expansion and positioning while microfilaments are required for centrosome separation in sea urchin eggs during fertilization and mitosis

Centrosomes undergo cell cycle-dependent changes in shape and separations, changes that govern the organization of the cytoskeleton. The cytoskeleton is largely organized by the centrosome; however, this investigation explores the importance of cytoskeletal elements in directing centrosome shape. Since the sea urchin egg during fertilization and mitosis displays dramatic and synchronous changes in centrosome shape, the effects of cytoskeletal inhibitors on centrosome compaction, expansion, and separation were explored by the use of anticentrosome immunofluorescence microscopy. Centrosome expansion and separation was studied during two phases: the transition after sperm incorporation, when the compact sperm centrosome enlarges and the sperm aster develops, and from prometaphase to telophase, when the compact spindle poles enlarge. Compaction was investigated when the dispersed centrosome at interphase condenses into the two spindle poles at prometaphase. Although centrosome expansion and separation typically occur concurrently, beta-mercaptoethanol results in centrosome separation independent of expansion. Microtubule inhibitors prevent centrosome expansion and separation, and expanded centrosomes collapse. Since pronuclear union is arrested by microtubule inhibitors, this treatment also affords the opportunity to explore the relative attractiveness of the male and female pronuclei for these centrosomal antigens. Both pronuclei acquire centrosomal material; though only the male centrosome is capable of organizing a functional bipolar mitotic apparatus at first division, the female centrosome nucleates a monaster. Microfilament inhibition (cytochalasin D) prevents centrosome separation but not expansion or compaction. These results demonstrate that as the centrosome shapes the cytoskeleton, the cytoskeleton alters centrosome shape.

Centrosome detection in sea urchin eggs with a monoclonal antibody against Drosophila intermediate filament proteins: characterization of stages of the division cycle of centrosomes

A mouse monoclonal antibody generated against Drosophila intermediate filament proteins (designated Ah6/5/9 and referred to herein as Ah6) is found to cross-react specifically with centrosomes in sea urchin eggs and with a 68-kDa antigen in eggs and isolated mitotic apparatus. When preparations stained with Ah6 are counterstained with a human autoimmune serum whose anti-centrosome activity has been established, the immunofluorescence images superimpose exactly. A more severe test of the specificity of the antibody demands that it display all of the stages of the centrosome cycle in the cell cycle: the flattening and spreading of the compact centrosomes followed by their division and the establishment of two compact poles. The test was made by an experimental design that uses a period of exposure of the eggs to 2-mercaptoethanol. This treatment allows observation of the stages of the centrosome cycle--separation, division, and bipolarization--while the chromosomes are arrested in metaphase. Mitosis is arrested in the presence of 0.1 M 2-mercaptoethanol. Chromosomes remain in a metaphase configuration while the centrosomes divide, producing four poles perpendicular to the original spindle axis. Microtubules are still present in the mitotic apparatus, as indicated by immunofluorescence and transmission electron microscopy. When 2-mercaptoethanol is removed, the chromosomes reorient to the poles of a tetrapolar (sometimes tripolar) mitotic apparatus. During the following cycle, the blastomeres form a monopolar mitotic apparatus. The observations of the centrosome cycle with the Ah6 antibody display very clearly all the stages that have been seen or deduced from work with other probes. The 68-kDa antigen that reacts with the Ah6 monoclonal antibody to Drosophila intermediate filament proteins must be a constant component of sea urchin centrosomes because it is present at all stages of the centrosome cycle.

[Comparison of prognostic nutrition indices in preoperative detection of risk patients. A prospective trial]

Malnutrition must be considered as a factor of risk in surgery and therefore it has to be taken into account in surgical planning. Many authors aggregated several measurements into an index or another mathematical model by stepwise regression or discriminant analysis. Hitherto none of these approaches has been subjected to a critical analysis designed to determine whether the information gained differentiates patients with increased operative risk from those without, to a degree that is clinically relevant. In a prospective study the predictive values of nutritional assessment techniques of various authors were examined in 246 surgical patients undergoing a major surgical procedure. The specificity, sensitivity, and validity of each assessment technique were determined. The statistical analysis showed that none of the assessment techniques separated patients who were at high risk from those who were at low risk in a statistically significant predictive power. Serum albumin level was a quite accurate prognostic indicator of postoperative morbidity and mortality. The mean complication rate in this study was 26.8%. Concerning the specificity, sensitivity, and validity the single measurement of the serum albumin had a predictive value as high as all other determined assessment techniques in this study. We contend that combining measurements into a statistically derived index is time-consuming and expensive and does not produce an assessment technique with sufficient predictive power to identity high risk patients in a clinically relevant fashion.

[Initial clinical experience using Dermodress, a new temporary biological skin substitute]

A chemically treated bovine skin, Dermodress, is presented as a long-term skin substitute. Dermodress was applied over denuded surfaces of debrided deep burns and was kept in place up to 56 days. At this time it was totally replaced by autograft, so we have no idea yet of how much longer it could have remained. It adheres to all contours of the debrided area, has hemostatic effect, and does not present any sign of infection or rejection. Dermodress can be removed in stages according to the availability of autografts, which may be applied immediately, since the exposed areas are clean and suitable for immediate grafting. Our clinical experience shows that Dermodress has most of the required properties of a long-term temporary skin substitute.

Experiments with a biological material for the closure of incisional hernias

A new preparation process was studied which should allow the implantation of collagen type I in its native structure in reconstructive surgery, in this special case for closure of incisional hernias. As experimental animals we used 30 female Lewis rats. A defect of the anterior abdominal wall measuring 3 cm X 4 cm was closed with our collagen substitute. Biopsies taken after 4, 6 and 8 weeks were examined morphologically. As criteria for revitalization and revascularization we used the type of infiltrating cells, the depth and density of infiltration and the formation of new blood vessels. After 4 weeks the implants were infiltrated by fibroblasts that decreased in density towards the centre. Good revascularization could be seen on the muscle-implant interface. After 6 weeks the density of infiltrating cells had increased markedly even to the centre of the collagen implant. Sporadically small vessels could be seen. Eight weeks after implantation the density of infiltrated cells was at the same high level, and capillary bundles could be seen within the whole implant. We believe that this collagen implant is suitable for the closure of hernias as shown by its physical and morphological properties. In particular it appears to guarantee and earlier and tighter closure of hernias than other materials.

[Chemotherapy of metastatic gastric cancer--x-ray follow-up]

In most cases of metastatic gastric cancer, treatment with cytostatic drugs seems to be justified. Responsiveness to chemotherapy, according to the MAF-schedule (Methotrexate, Adriamycin, 5-Fluorouracil) was reported to be successful in 50% of this cancer type.

The contribution of small gut to the 3-methylhistidine metabolism in the adult rat

Twenty male adult Sprague-Dawley rats received parenteral nutrition following a duodenoileostomy which left only 8% to 10% of the small gut intact. On the first postoperative day, the urinary 3-methylhistidine (3-MH) excretion rose to 1.5 to 1.7 times the preoperative level but fell again within 12 to 14 days to the basal level. A control group of 10 rats with small gut anastomosis without resection yielded similar results. We conclude that, at least in rats, the small intestine does not make a significant contribution to 24-hour urinary excretion of 3-MH. The transient postoperative rise in 3-MH excretion is probably due to postinjury metabolism.

Early T cell differentiated chronic myeloid leukemia blast crisis with rearrangement of the breakpoint cluster region but not of the T cell receptor beta chain genes

Early T cell differentiation is described in a case of Philadelphia chromosome-positive chronic myeloid leukemia (CML) in blast crisis, supporting multi-lineage differentiation potential of CML precursor cells. In the absence of myeloid markers, strong positivity for terminal deoxynucleotidyl transferase (TdT) and reactivity with T cell antibody 3A1, but lack of more mature T cell antigens, provided evidence for immature T cell differentiation. Molecular analysis of the breakpoint cluster region (bcr) in chromosome 22 revealed a rearrangement and thus confirmed the CML origin of the early T cell blasts. T cell receptor beta chain sequences were found in germline configuration and therefore suggest a very immature stage of T cell differentiation in the CML blasts.

Measurement of cell-mediated immunity against bovine papilloma virus by lymphoproliferative reactions

To study cellular immunity towards bovine papillomavirus (BPV), calves were infected intradermally with BPV-1, and the cellular immune response was measured by the lymphocyte proliferation assay. Peripheral blood lymphocytes were obtained which in control experiments were highly reactive towards mitogen stimulation. Different batches of BPV-1 were prepared by the use of density gradients. In the first set of experiments, a nonspecific mitogenic effect of the virus preparation was observed. This effect was obviously caused by soluble molecules contained in the virion-free supernatant obtained after ultracentrifugation of the viruses. Subsequently, we obtained highly purified virions which did not share the nonspecific mitogenic effect. The data obtained with these virions showed no responses of untreated control animals but a short-lived in vitro lymphoproliferative response 2 to 3 weeks after infection. This response then disappeared and was followed by a period of non-responsiveness which lasted as long as we tested the animals.

[Choice of a class I intravenous anti-arrhythmic drug in severe ventricular arrhythmias]

In the choice of a Class I intravenous antiarhythmic medication for the treatment of threatening ventricular extrasystoles, one must take into account the speed of action of the product, its effects on hemodynamics and conduction as well as its efficacy. The rapidity of action implies the ability to reach, without delay, a therapeutic plasma level which will depend upon the distribution volume and the dose injected. An effective plasma level may be quickly reached following the intravenous administration of lidocain, disopyramide, lorcainide, tocainide and flecainide. All antiarhythmic medications have an unfavorable effect on hemodynamics; xylocain and ajmaline seem to depress the least the left ventricular function, followed by lorcainide. Unfavorable effects on the atrio-ventricular conduction are observed with substances of type IC; the duration of QRS may be affected as well by antiarhythmic medications IA and IC, with a lengthening of QT being mostly noted type IA medications. Comparison of the efficacy of antiarhythmic medications requires a strict methodology and the current data from the literature do not permit to assert with certainty the superiority of one antiarhythmic medication over the others.

[Anthropometric parameters]

Anthropometry is defined as the comparative measurement and study of the human body. Anthropometric measurements have been used for many years to assess the nutritional status of individuals and populations in the United States. More recently anthropometric measurements have become a routine part of the nutrition assessment of surgical patients. Upper arm anthropometry and handgrip dynamometry are rapid and inexpensive tests for detecting malnutrition, but they are not useful for preoperative screening to predict postoperative morbidity because appropriate standards are missing in Europe. In a prospective study none of these preoperatively measured variables were of predictive value to postoperative complications, relating the method to its specificity, sensitivity, and validity.

[Ultrasonic diagnosis of intestinal mural hematoma during anticoagulant therapy]

Report on a patient with a complication of anticoagulant treatment, in whom intramural colon wall bleeding was diagnosed and followed up by ultrasonography.

The oncogenic activation of human p21ras by a novel mechanism

Single amino acid changes were introduced into normal (non-oncogenic) and activated forms of the human H-ras protein at a position (residue 116) proposed on structural grounds to represent a contact site with guanine nucleotides. Substitutions at this site could significantly reduce the ability of both forms to bind and hydrolyze guanosine 5'-triphosphate; these substitutions, however, did not necessarily diminish the transforming capacity of activated derivatives. One substitution that severely impairs these functions activated the transforming potential of the otherwise normal polypeptide.

[Pigmented villonodular synovitis]

During a 8-year period, recurrent swelling of the right knee-joint was observed in a 31-year-old female. Although only minimal pain was present, flexion of the knee-joint was severely limited. Bearing in mind the extent of the swelling, the initial diagnostic procedures were suggestive of a malignant neoplasm. Biopsy of the knee-joint led however to the diagnosis of a pigmented villo-nodular synovitis. The postoperative course after synovectomy of the knee-joint was uneventful. Although benign, this lesion has to be followed-up closely, due to the recurrence-rate of 33%.

[Adjuvant artificial nutrition in tumor surgery]

Malnutrition can effect negatively the results of major cancer surgery. Adequate preoperative nutritional therapy helps to overcome the catabolic situation of malnourished cancer patients and leads to a reduction of postoperative morbidity and mortality. The beneficial effect of nutritional therapy after major cancer surgery is generally accepted, despite there is a lack of comparative clinical trials which could support this opinion. Forced feeding stimulated tumor growth in certain animal models. These findings seem to have not any clinical relevance in cancer surgery.

A simple technique for long-term intravenous feeding in unrestrained rats

A model for parenteral nutrition of unrestrained rats is described. Apparatus and nutrient solutions are very simple, inexpensive, and commonly available. The major survival time is at least 6-8 weeks. During the parenteral nutrition the rats gain weight and are in a excellent general health. The cumulative nitrogen balance is highly positive with a retention of 95%.