Stromal cells from human long-term marrow cultures are mesenchymal cells that differentiate following a vascular smooth muscle differentiation pathway

In human long-term marrow cultures connective tissue-forming stromal cells are an essential cellular component of the adherent layer where granulomonocytic progenitors are generated from week 2 onward. We have previously found that most stromal cells in confluent cultures were stained by monoclonal antibodies directed against smooth muscle- specific actin isoforms. The present study was carried out to evaluate the time course of alpha-SM-positive stromal cells and to search for other cytoskeletal proteins specific for smooth muscle cells. It was found that the expression of alpha-SM in stromal cells was time dependent. Most of the adherent spindle-shaped, vimentin-positive stromal cells observed during the first 2 weeks of culture were alpha- SM negative. On the contrary, from week 3 to week 7, most interdigitated stromal cells contained stress fibers whose backbone was made of alpha-SM-positive microfilaments. In addition, in confluent cultures, other proteins specific for smooth muscle were detected: metavinculin, h-caldesmon, smooth muscle myosin heavy chains, and calponin. This study confirms the similarity between stromal cells and smooth muscle cells. Moreover, our results reveal that cells in vivo with the phenotype closest to that of stromal cells are immature fetal smooth muscle cells and subendothelial intimal smooth muscle cells; a cell subset with limited development following birth but extensively recruited in atherosclerotic lesions. Stromal cells very probably derive from mesenchymal cells that differentiate along this distinctive vascular smooth muscle cell pathway. In humans, this differentiation seems crucial for the maintenance of granulomonopoiesis. These in vitro studies were completed by examination of trephine bone marrow biopsies from adults without hematologic abnormalities. These studies revealed the presence of alpha-SM-positive cells at diverse locations: vascular smooth muscle cells in the media of arteries and arterioles, pericytes lining capillaries, myoid cells lining sinuses at the abluminal side of endothelial cells or found within the hematopoietic logettes, and endosteal cells lining bone trabeculae. More or less mature cells of the granulocytic series were in intimate contact with the thin cytoplasmic extensions of myoid cells. Myoid cells may be the in vivo counterpart of stromal cells with the above-described vascular smooth muscle phenotype.     

Management of a subcutaneous colostomy perforation

Colostomy perforation is an infrequent but often diasastrous and lethal complication. In the majority of patients, the traumatic performation occurs during irrigation through the colostomy stoma. This case report reviews the clinical course of a patient with a subcutaneous colostomy perforation and the subsequent development of an extensive abscess. Aspects of the management included mobilization of the colostomy and thorough surgical debridement and drainage. In addition, the report introduces the use of the new semisynthetic biologic dressing, BioBrane^®. This synthetic, semipermeable skin substitute served as a temporary dessing, provided good stability, and supported the application of a stoma appliance.     

Sp alpha I/78: a mutation of the alpha I spectrin domain in a white kindred with HE and HPP phenotypes

Limited tryptic digestion of spectrin (Sp) from seven related individuals manifesting hereditary elliptocytosis (HE) or hereditary pyropoikilocytosis (HPP) phenotypes revealed the presence of a novel peptide with a molecular weight of 78 Kd and a concomitant decrease in the alpha I domain (80-Kd peptide), which is the domain involved in the dimer self-association process. Sp from the normal members of this white family exhibited a normal peptide pattern, as compared with controls. The abnormal peptide pattern was associated with a decreased ability of Sp dimer to self-associate. In this kindred in which three generations were available for study, the clinical manifestations were quite variable and ranged from the asymptomatic HE carrier state to hemolytic HE or to severe anemia requiring splenectomy. The severity of the disease appeared to be correlated both with the amount of mutant spectrin (31% to 69%) and with the excess of the Sp dimer found in the membrane (26% to 60%, compared with a normal value of 5.6% +/- 2.2%). Partial amino acid sequencing showed that the alpha I/78-Kd peptide resulted from cleavage at lysine residue 10 of the alpha I/80-Kd domain. Knowledge of the exon/intron structure of cloned genomic DNA encoding the alpha I domain allowed us to amplify in vitro a DNA fragment containing the third exon of the alpha-spectrin gene. The amplified fragment was subcloned and sequenced. A G to T transversion was found in the 39th codon (AGT for AGG), which changed the normal arginine to a serine. Hybridization of amplified DNAs with allele- specific oligonucleotides corresponding to the normal and mutant sequences confirmed the presence of the mutation in three other HE members of the family (the propositus mother, brother, and sister).     

A phase 1B trial of humanized monoclonal antibody M195 (anti-CD33) in myeloid leukemia: specific targeting without immunogenicity

This trial studied the biodistribution, pharmacology, toxicity, immunogenicity, and biologic characteristics of a trace-labeled, anti- CD33, humanized monoclonal antibody M195 (Hu-M195) in patients with relapsed and refractory myeloid leukemia. Hu-M195 is a computer- modeled, "complementarity-determining region-grafted," IgG1, humanized version of M195. M195 is a murine monoclonal antibody that reacts with CD33, a 67-kD glycoprotein expressed on early myeloid progenitor cells and myeloid leukemia (acute myelogenous leukemia and chronic myelogenous leukemia) cells, but not normal stem cells. 131I-murine- M195 has already shown significant ability to cytoreduce patients with relapsed or refractory myeloid leukemias. Hu-M195 has higher avidity than the original mouse monoclonal antibody and, unlike murine M195, has the capability to mediate antibody-dependent cellular cytotoxicity against leukemia targets. Thirteen patients with relapsed or refractory myelogenous leukemia were treated with Hu-M195 at 4 levels of 0.5, 1.0, 3.0, and 10.0 mg/m2 in a phase I trial. Patients received a total of 6 doses per patient over 18 days. Two patients were retreated for a total of 12 doses. The first dose of Hu-M195 was trace-labeled with 131I to allow detailed pharmacokinetic and biodistribution studies by serial sampling of blood, radioimmunoassays of cells, and whole-body gamma- camera imaging. Cumulative total doses of up to 216 mg of Hu-M195 were administered safely. Reversible fever and rigors were observed after infusion at the highest dose levels. The entire bone marrow was specifically and clearly imaged within hours after infusion, with optimal biodistribution occurring at the 3 mg/m2 level. Adsorption of Hu-M195 onto targets in vivo was demonstrated by flow cytometry; near saturation of available sites occurred at the 3 mg/m2 dose level. Plasma and whole body half lives were 38 and 51 hours, respectively, which may reflect continual replenishment of target sites on new leukemia cells. 131I-Hu-M195 was rapidly internalized into the target cells in vivo within 1 hour. Human antihuman antibody responses were not observed. In conclusion, Hu-M195 can be administered safely in multiple doses, without significant toxicity or any evidence of immunogenicity, and can localize rapidly and efficiently to the bone marrow in patients with myeloid leukemias. Additional phase II trials with this agent alone or in combination with cytokines or isotopes are warranted at the optimal biologic dose.     

Hypotonic duodenoscopy

Inducing duodenal hypotonia by the intravenous injection of propantheline bromide is a simple, safe procedure that will permit this organ to be visualized adequately by endoscopy. Twenty-five consecutive patients with suspected duodenal pathology received an intravenous injection of propantheline at the time the pylorus was being viewed through the endoscope. Immediately after the injection, the pylorus dilated and the endoscope was passed easily into the duodenal bulb, where good visualization was achieved. A small bulb syringe attached to the air channel of the endoscope and gentle insufflation of air permitted good visualization of the second portion of duodenum. While the propantheline method is not necessary in all patients undergoing duodenoscopy, those in whom it is difficult to pass the endoscope through the pylorus or in whom antroduodenal motility precludes adequate examination, injection of the antispasmodic provides one easy, safe method for examining the duodenum by duodenoscopy.     

Effect of HLA Bw4/Bw6 compatibility on platelet transfusion responses of refractory thrombocytopenic patients

Platelet transfusions from donors matched for cross-reactive antigens have been shown to be effective in providing hemostasis in alloimmunized thrombocytopenic patients. A significant number of these transfusions, however, fail to provide posttransfusion platelet recoveries. We investigated incompatibility in the Bw4/bw6 system as a possible explanation for these failures. The Bw4/Bw6 system is a biallelic antigen system closely associated with HLA-B. HLA-B locus antigens that are cross-reactive frequently differ in their Bw4/Bw6 specificity. Posttransfusion platelet recoveries from 21 alloimmunized thrombocytopenic patients homozygous for Bw4 or Bw6 and transfused with both Bw4/Bw6 compatible and incompatible platelets were analyzed. The mean 1-hr posttransfusion recovery was 84% following Bw4/Bw6-compatible platelets versus 52% with Bw4/Bw6-incompatible platelets (p less than 0.02). Twenty-four hours following transfusion, mean recoveries were 44% and 24%, respectively, (p less than 0.01). A subgroup of 8 patients (38%) was identified who had markedly lower responses following Bw4/Bw6- incompatible transfusions as compared to Bw4/Bw6-compatible transfusions (mean recoveries: 1 hr--compatible 100%, incompatible 27%, p less than 0.001; 24 hr--compatible 45%, incompatible 7%, p less than 0.01). These data suggest that the Bw4/Bw6 antigen system has clinical significance for some patients requiring platelet transfusion therapy and, when appropriate, should be considered in the selection of donors.     

Neutrophil adhesiveness during prostacyclin and heparin hemodialysis

We evaluated neutrophil adhesive function in patients undergoing chronic hemodialysis using either prostacyclin or heparin as antithrombotic agents. Patients underwent successive hemodialyses with prostacyclin (4 ng/kg/min) and heparin. There were no significant differences noted in neutrophil adhesive function during either dialysis: transient neutropenia developed in each case; impaired neutrophil adhesiveness to plastic developed during both dialyses; neutrophil aggregation was diminished when compared to predialysis responses during both dialyses. Furthermore, the number of circulating Fc-receptor-bearing neutrophils fell significantly during both prostacyclin and heparin hemodialysis. Our study demonstrates that substitution of prostacyclin for heparin in doses that do not cause hypotension, does not prevent neutropenia or alter the diminished neutrophil adhesiveness that occurs during heparin hemodialysis.     

Neurologic complications after allogeneic marrow transplantation for sickle cell anemia [see comments]

Seven of 21 patients with sickle cell anemia developed neurologic complications 5 to 243 days (median, 33 days) after allogeneic marrow transplantation. Among these 7 patients, indications for transplantation included either a past history of stroke (4 patients) or recurrent severe vaso-occlusive events (3 patients). All received marrow from an HLA-identical sibling after preparation with busulfan and cyclophosphamide, and in 4 patients with antithymocyte globulin. Five of 6 patients developing seizures received anticonvulsant and supportive treatment with resolution of neurologic abnormalities. Three patients experienced intracranial bleeding, which was fatal in two. Of the 14 patients free of neurologic complications, 4 patients had experienced stroke before transplantation. However, among all patients with prior stroke, the incidence of intracranial hemorrhage was 38% (3/8), whereas none of the 13 patients without prior stroke developed posttransplant intracranial bleeding (P = .026). We conclude that patients with sickle cell anemia are at increased risk for neurologic complications after marrow ablative therapy and that patients with prior stroke are at increased risk for intracranial hemorrhage. Transplantation of patients before the onset of overt stroke may reduce this risk.     

Crohn's disease with spontaneous ileoumbilical and ileovesical fistulae

Summary A 17-year-old male with Crohn's disease involving the terminal ileum and cecum developed an umbilical fistula in the absence of previous surgery. While on intravenous hyperalimentation he developed an enterovesical fistula and was successfully treated by surgical resection. This combination of an enterovesical and umbilical fistula has not been previously reported. An aggressive approach to treatment is suggested.