Gianturco expandable metallic biliary stents: results of a European clinical trial

Eleven patients with benign strictures (after choledochojejunostomy, n = 10; chronic pancreatitis, n = 1) and 16 with malignant biliary strictures (cancer of the pancreas, n = 7; cholangiocarcinoma, n = 5) were treated with a self-expanding metallic biliary stent. The patients with benign disease had failed treatment with surgical reconstruction and transhepatic balloon dilation. All patients had immediate relief of jaundice and cholangitis. In a follow-up period of 6-21 months, nine of the 11 patients with benign disease had no difficulties with infection, pruritus, or recurrent jaundice. In patients with malignant strictures, the stent produced relief of biliary obstruction unless recurrent tumor invaded the bile ducts. With careful patient selection, this stent appears to be useful in the management of biliary obstruction, particularly in benign disease.     

True identity by immunohistochemistry and molecular morphology of undifferentiated malignancies of the head and neck

Although conventional squamous carcinomas can often be recognized with little difficulty by experienced pathologists, it remains a fact that a substantial number of head and neck malignancies are capable of posing real challenges to the diagnostic pathologist. Those head and neck tumors showing the least kinship with normal host tissues—that is, the undifferentiated malignancies—are a particular problem and an approach to dealing with them is traced out below. As a matter of basic light microscopy, these tumors can usually be relegated to 1 of 4 categories: small round cell tumors, spindle cell tumors, large polygonal cell (epithelioid) tumors, and pleomorphic tumors. Once they have been so subclassified, these lesions can then be studied by immunohistochemistry and, when necessary, by molecular methods as well. Immunohistochemistry often permits these tumors to be assigned to a particular tissue type, specifically, epithelial, mesenchymal, lymphoid, or melanocytic. Application of additional immunohistochemical antibodies, in turn, can permit further refinement of this impression (eg, allowing distinction of a neuroendocrine tumor from a carcinoma). In selected instances, molecular techniques (such as in situ hybridization) may be employed both for diagnostic as well as for prognostic purposes. It should be borne in mind, however, that the pathologist's diagnosis will sometimes only be as good as the clinical information provided, which is why the diagnosis of undifferentiated malignancies of the head and neck truly is a multifaceted process, demanding the close cooperation of pathologists, clinicians, and radiologists. © 2009 Wiley Periodicals, Inc. Head Neck, 2009     

Serum amyloid P inhibits dermal wound healing

The repair of open wounds depends on granulation tissue formation and contraction, which is primarily mediated by myofibroblasts. A subset of myofibroblasts originates from bone‐marrow‐derived monocytes which differentiate into fibroblast‐like cells called fibrocytes. Serum amyloid P (SAP) inhibits differentiation of monocytes into fibrocytes. Thus, we hypothesized that the addition of exogenous SAP would hinder the normal wound healing process. Excisional murine dorsal wounds were either injected with SAP (intradermal group) or the mice were treated with systemic SAP (intraperitoneal group) and compared with animals treated with vehicle. Grossly, SAP‐treated wounds closed slower than respective controls in both groups. Histologically, the contraction rate was slower in SAP‐treated wounds in both groups and the reepithelialization rate was slower in the intraperitoneal group. Furthermore, significantly less myofibroblasts expressing α‐smooth muscle actin were noted in the intraperitoneal group wounds compared with controls. These data suggest that SAP delays normal murine dermal wound healing, probably due to increased inhibition of fibrocyte differentiation, and ultimately a decreased wound myofibroblast population. SAP may provide a potential therapeutic target to prevent or limit excessive fibrosis associated with keloid or hypertrophic scar formation. Furthermore, SAP removal from wound fluid could potentially accelerate the healing of chronic, nonhealing wounds.     

Autocrine secretion of GM-CSF in acute myeloblastic leukemia

Three cases of acute myeloblastic leukemia (AML) were identified in which clonogenic cells proliferated autonomously in vitro. Cells from two of these cases were found to secrete a colony-stimulating factor (CSF) that was immunologically and molecularly related to GM-CSF. Growth of AML-CFU could be blocked by the addition of a neutralizing antiserum to GM-CSF. Northern blot hybridization of leukemic cell mRNA with a cDNA probe for the GM-CSF gene revealed a 1-kb message identical in size to the normal GM-CSF message in stimulated T cells. No GM-CSF message was detected in the third case. These results indicate that constitutive expression of the GM-CSF gene, apparently by leukemic cells, can result in autonomous in vitro proliferation of AML-CFU in some cases of AML.     

Distribution of 11q23 breakpoints within the MLL breakpoint cluster region in de novo acute leukemia and in treatment-related acute myeloid leukemia: correlation with scaffold attachment regions and topoisomerase II consensus binding sites

A major unresolved question for 11q23 translocations involving MLL is the chromosomal mechanism(s) leading to these translocations. We have mapped breakpoints within the 8.3-kb BamHI breakpoint cluster region in 31 patients with acute lymphoblastic leukemia and acute myeloid leukemia (AML) de novo and in 8 t-AML patients. In 23 of 31 leukemia de novo patients, MLL breakpoints mapped to the centromeric half (4.57 kb) of the breakpoint cluster region, whereas those in eight de novo patients mapped to the telomeric half (3.87 kb). In contrast, only two t-AML breakpoints mapped in the centromeric half, whereas six mapped in the telomeric half. The difference in distribution of the leukemia de novo breakpoints is statistically significant (P = .02). A similar difference in distribution of breakpoints between de novo patients and t-AML patients has been reported by others. We identified a low- or weak-affinity scaffold attachment region (SAR) mapping just centromeric to the breakpoint cluster region, and a high-affinity SAR mapping within the telomeric half of the breakpoint cluster region. Using high stringency criteria to define in vitro vertebrate topoisomerase II (topo II) consensus sites, one topo II site mapped adjacent to the telomeric SAR, whereas six mapped within the SAR. Therefore, 74% of leukemia de novo and 25% of t-AML breakpoints map to the centromeric half of the breakpoint cluster region map between the two SARs; in contrast, 26% of the leukemia de novo and 75% of the t-AML patient breakpoints map to the telomeric half of the breakpoint cluster region that contains both the telomeric SAR and the topo II sites. Thus, the chromatin structure of the MLL breakpoint cluster region may be important in determining the distribution of the breakpoints. The data suggest that the mechanism(s) leading to translocations may differ in leukemia de novo and in t-AML.     

A limited temporal window for the derivation of multilineage repopulating hematopoietic progenitors during embryonal stem cell differentiation in vitro

Embryonal stem cells have been shown to differentiate in vitro into all hematopoietic lineages. This has been used successfully as one approach to the study of genetic events occurring during haematopoiesis. However, studies on the commitment of mesodermal precursors to the hematopoietic lineage have been limited due to the inability to define a system in which embryonal stem (ES) cells will give rise to primitive hematopoietic stem cells in vitro. Using a colony forming assay (CFU- A), we determined that the earliest time point at which primitive multilineage hematopoietic precursors can be detected during ES cell differentiation in vitro in the absence of exogenous conditioned medium or stromal cell culture is 4 days. Lethally irradiated adult recipient mice that received differentiated ES cells from this time point survived for more than 3 weeks; and in two out three experiments, peripheral blood from these animals contained ES-derived progeny. Fluorescence activated cell sorting (FACS) found ES-derived CD45+ hematopoietic cells in both lymphoid and myeloid compartments at 12 weeks posttransplantation, suggesting that the population of day 4 differentiated ES cells contains primitive hematopoietic precursors. A preliminary RT-PCR analysis of gene expression around this time point suggests that there are very few hematopoietic cells present. This approach should prove useful in studies of genetic control of commitment to and maintenance of hematopoietic lineages in vitro and in vivo.     

Indication of an involvement of interleukin-1 beta converting enzyme- like protease in intramedullary apoptotic cell death in the bone marrow of patients with myelodysplastic syndromes

Our previous studies using in situ end labeling (ISEL) of fragmented DNA revealed extensive apoptotic cell death in the bone marrows (BM) of patients with myelodysplastic syndromes (MDS) involving both stromal and hematopoietic cells. In the present report we show greater synthesis of interleukin-1 beta (IL-1 beta) in 4 hour cultures of density separated BM aspirate mononuclear (BMAM) cells from MDS patients as compared to the cultures of normal BM from healthy donors or lymphoma patients (1.7 +/- 0.37 pg/10(5) cells, n = 29 v 0.42 +/- 0.24 pg/10(5) cells, n = 11, respectively, P = .049). Further, these amounts of IL-1 beta in MDS showed a significant correlation with the extent of apoptosis detected by ISEL in corresponding plastic embedded BM biopsies (r = .480, n = 30, P = .007). In contrast normal BMs did not show any correlation between the two (r = .091, n = 12, P = .779). No significant correlation was found between the amounts of IL-1 beta and % S-phase cells (labeling index; LI%) in MDS determined in BM biopsies using immunohistochemistry following in vivo infusions of iodo- and/or bromodeoxyuridine. Neither anti-IL-1 beta antibody nor IL-1 receptor antagonist blocked the apoptotic death of BMAM cells in 4 hour cultures (n = 5) determined by ISEL (apoptotic index; AI%), although the latter led to a dose-dependent accumulation of active IL-1 beta in the culture supernatants. On the other hand, a specific tetrapetide- aldehyde inhibitor of ICE significantly retarded the apoptotic death of BMAM cells at 1 mumol/L in 5/6 MDS cases studied (AI% = 2.99 +/- 0.30 in controls v 1.58 +/- 0.40 with ICE-inhibitor, P = .05) and also reduced the levels of active IL-1 beta synthesized (5.59 +/- 2.63 v 2.24 +/- 0.93 pg/10(6) cells, respectively). In normal cells, neither IL-1 blockers nor the ICE inhibitor showed any effect on the marginal increase in apoptosis observed in 4 hour cultures. Our data thus suggest a possible involvement of an ICE-like protease in the intramedullary apoptotic cell death in the BMs of MDS patients.     

Tyrosine administration reduces blood pressure and enhances brain norepinephrine release in spontaneously hypertensive rats.

Administration of L-tyrosine to normotensive or spontaneously hypertensive rats reduces blood pressure. The effect is maximal within 2 hr of injection. In spontaneously hypertensive rats, a dose of 50 mg/kg, intraperitoneally, reduces blood pressure by about 12 mm Hg (1 mm Hg = 1.33 x 10(2) pascals); a dose of 200 mg/kg produces the maximal effect, a reduction of about 40 mm Hg. Tryptophan injection (225 mg/kg) also lowers blood pressure in spontaneously hypertensive rats, but only by about half as much as an equivalent dose of tyrosine. Other amino acids tested (leucine, isoleucine, valine, alanine, arginine, and aspartate) do not affect blood pressure. Tyrosine injection appears to reduce blood pressure via an action within the central nervous system, since the effect can be blocked by co-administering other large neutral amino acids that reduce tyrosine's uptake into the brain. That tyrosine's antihypertensive action is mediated by an acceleration in norepinephrine or epinephrine release within the central nervous system is suggested by the concurrent increase that its injection produces in brain levels of methoxyhydroxyphenylethylglycol sulfate.     

Gene transfer into hematopoietic progenitor cells from normal and cyclic hematopoietic dogs using retroviral vectors

The Moloney murine leukemia retrovirus-derived vector N2 was used to transfer the bacterial NeoR gene (conferring resistance to the neomycin analogue G418) into hematopoietic progenitor cells. Approximately 5% of day seven CFU-GM were resistant to 2,000 micrograms/ml G418, using a supernatant infection protocol in the absence of vector-producing cells. A greater proportion of CFU-GM colonies were recovered relative to uninfected controls as the stringency of selection was diminished. Enzyme activity was detected in drug-resistant colonies, confirming that the resistant colonies obtained after infection with N2 represented cells producing neomycin phosphotransferase. Activity in the CFU-GM colonies approached 50% of that of drug-resistant vector- producing cells on a per cell basis. To test the hypothesis that more rapidly cycling bone marrow cells would be more susceptible to vector infection, we treated progenitor cells obtained from cyclic hematopoietic (CH) dogs with the N2 vector. Despite the increased numbers of hematopoietic progenitor cells obtained from CH dogs, the proportion of G418-resistant CFU-GM did not increase over that obtained with N2-infected normal marrow. These results demonstrate that retroviral vectors can be used to transfer and express exogenous genes in canine hematopoietic progenitor cells.     

Short remission durations in therapy-related leukemia despite cytogenetic complete responses to high-dose cytarabine

Seventeen patients with therapy-related myelodysplastic syndrome (t- MDS) or therapy-related acute nonlymphocytic leukemia (t-ANLL) were treated with single-agent high-dose cytarabine (HDAC; 1 to 3 g/m2 every 12 hours for 12 doses). The initial neoplasm was still present in eight patients when t-MDS/t-ANLL developed. Fifteen of the 16 patients with chromosomal abnormalities in bone marrow cells had loss or rearrangement of chromosomes 5 and/or 7. One patient had a t(15;17), and one had inadequate material for cytogenetic analysis. Twelve patients had normal metaphase cells (3% to 71%). Indications for HDAC therapy were progressive pancytopenia in 13 patients or rising blast count in four. Five patients died of marrow hypoplasia following therapy. Four others had refractory t-ANLL and died within the subsequent 5 months. Only one of ten patients with a poor performance status (PS greater than or equal to 2 using the ECOG scale) achieved a complete remission, but all seven patients with a good performance status (PS less than or equal to 1) had a complete remission. Hematologic remissions were achieved in 8 patients (47%) after one (6 patients) or two (2 patients) induction courses and were confirmed by recovery of a 100% normal marrow karyotype in six of the seven patients who were retested. Patients in remission received one to four consolidation courses with HDAC alternating with cytarabine/doxorubicin, but seven relapsed within 8 months (median remission duration, 5 months). In every case, the original chromosomal abnormality reappeared at relapse. HDAC has a high response rate for good-performance patients with t-MDS/t-ANLL, but complete remissions are short even when confirmed cytogenetically and consolidated intensively.