Evaluation of the nitrosamine hypothesis of gastric carcinogenesis in precancerous conditions.

A 24 hour gastric aspiration study was carried out on nine Polya gastrectomy, eight pernicious anaemia, and nine matched control subjects. Intragastric pH, bacteria, nitrite, and N-nitroso compounds were assessed half hourly whilst ambulant and hourly when in bed. Both total and nitrate reducing bacterial counts were positively related to pH (chi 2 = 279.3; p less than 0.001), as was nitrite concentration (F = 19.1; p less than 0.0001). By contrast, total (F = 40.6; p less than 0.0001) and stable (F = 257.4; p less than 0.0001) N-nitroso compound concentrations were negatively related to pH. Clear differences in these gastric juice factors were not apparent between matched control and either pernicious anaemia, or Polya gastrectomy because the Polya gastrectomy and matched control groups were heterogeneous for gastric acidity. Thus, although eight of eight pernicious anaemia subjects were hypoacidic (defined as intragastric pH greater than 4 for greater than 50% of both daytime and night time periods), only five of nine Polya gastrectomy and two of nine matched control subjects were hypoacidic. When subjects were rearranged into hypoacidic (n = 15) and acidic (n = 11) groups, bacterial counts (p less than 0.01) and nitrite concentrations (p less than 0.01) were higher, whereas N-nitroso compounds tended to be lower (NS) in the hypoacidic group. These data suggest that, although hypoacidity predisposes to bacterial overgrowth and nitrite generation, it does not enhance nitrosation. Instead, this is maximal at low pH, suggesting chemical rather than bacterial nitrosation, contrary to the nitrosamine hypothesis of gastric carcinogenesis.     

5-Aminosalicylic Acid Enemas in Refractory Distal Ulcerative Colitis: A Randomized, Controlled Trial

5-Aminosalicylic acid (5-ASA), the presumed active moiety of sulfasalazine, has shown clinical efficacy when administered per rectum as initial therapy to patients with distal ulcerative colitis. We report the results of a randomized double-blind trial comparing nightly retention of a 4-g 5-ASA enema with continued administration of hydrocortisone enemas in 18 patients with persistent active distal ulcerative colitis after at least a 3-wk course of treatment with 100-mg hydrocortisone enemas with or without oral sulfasalazine. Continuation of hydrocortisone enemas rather than placebo was used in the control group to reflect the realistic alternative therapy likely to be employed in current practice. Response to therapy was assessed after 3 wk by comparing pretreatment and posttreatment point scores of clinical, sigmoidoscopic, and histological severity. Improvement in clinical score was achieved in seven of nine 5-ASA enema-treated patients versus one of nine hydrocortisone enema-treated patients (p less than 0.05). Sigmoidoscopic and histological improvement generally paralleled clinical improvement. We conclude that in patients with distal ulcerative colitis unresponsive to standard therapy, treatment with 5-ASA enemas results in significant short-term clinical and sigmoidoscopic improvement in a majority of cases. Moreover, a significantly greater number of refractory patients improve when switched to 5-ASA enemas than when continued on standard therapy.     

Immune complex-induced enteropathy in the rat

Adult male Sprague-Dawley rats injected with preformed rat anti-bovine serum albumin antibody-bovine serum albumin complexes prepared in fivefold antigen excess, developed intestinal lesions consisting of annular bands of serosal hyperemia alternating with nonhyperemic bands, causing a striped appearance. Histologically, vascular congestion and mucosal edema were observed; more severe lesions were accompanied by hemorrhage, epithelial necrosis and sloughing, and modest polymorphonuclear leukocyte infiltration. The lesions developed rapidly and were accompanied by hemoconcentration. A correlation between the dose of immune complexes injected and the intensity and extent of intestinal lesions was noted. The pathogenetic mechanism of the lesions was not determined. The similarity of the lesions to those observed in systemic anaphylaxis in the rat and experimental and clinical shock was cited. The implications of immune complex-induced enteropathy for studies of immune complex clearance by the mononuclear phagocyte system were considered.     

Differential induction of apoptosis in lymphoid tissues during sepsis: variation in onset, frequency, and the nature of the mediators

Apoptosis (Ao), is a process by which cells undergo a form of nonnecrotic cellular suicide. Although for most cells this is a constitutive process, it can be induced in immature and differentiating immune cell populations by stress mediators associated with inflammation. This inducible form of A(o) is referred to as programmed cell death. However, it is not clear whether hematopoietic cell populations such as the thymus and bone marrow are induced to undergo A(o) during polymicrobial sepsis. To assess this, thymocytes, bone marrow cells, or splenocytes (as a source of comparative nonhematopoietic cells) were harvested from C3H/HeN mice at 1, 4, or 24 hours after cecal ligation and puncture (CLP; to induce polymicrobial sepsis) or sham-CLP (Sham). The results showed that mixed bone marrow cells ex vivo, although not to the same extent as thymus, showed a marked increase in the percentage of cells in A(o), increased endonuclease activity, and a significant decrease in cell yield at 24 hours but not at 4 hours after CLP. Similar changes were not evident in splenocytes. Phenotypic, as well as morphologic assessment, indicated that most of the increase in apoptotic cells in the thymus was associated with the immature T cells (CD4+CD8+) and CD8-CD4- cells. In contrast, the increase in bone marrow cell A(o) was associated with only the B220+ cells, with no significant contribution from myeloid cells. Treatment of CLP mice in vivo with either RU-38486 or PEG-(rsTNF- R1)2 was unable to reverse the increased A(o) in the bone marrow of these animals. Taken together, these findings indicate that A(o) as a process induced by polymicrobial sepsis is not limited to the thymus, but can also be detected in the bone marrow. However, unlike thymic A(o), bone marrow is not affected directly/indirectly by glucocorticoids or tumor necrosis factor released during sepsis.     

Pharmacokinetics and immunomodulatory properties of intravenously administered recombinant human interleukin-10 in healthy volunteers

Normal volunteers received single doses of recombinant human interleukin-10 (rhIL-10; n = 6 per group) or placebo (n = 3 per group) by intravenous injection to characterize pharmacokinetics, tolerability, and immunomodulatory effects. Dosages were 0.1, 0.5, 1.0, 2.5, 5.0, 10.0, 25.0, 50.0, and 100.0 micrograms/kg. Dose-related adverse effects consisted of a mild-to-moderate flu-like syndrome characterized by fever with chills, headache, and myalgias at the highest dose. The mean terminal phase t1/2 ranged from 2.3 +/- 0.5 to 3.7 +/- 0.8 hours. Dose-related effects of rhIL-10 included transient increases of circulating neutrophils and monocytes and decreases of lymphocytes. rhIL-10 markedly suppressed, in a time- and dose-dependent manner, the synthesis of the inflammatory cytokines IL-1 beta and tumor necrosis factor alpha by whole blood stimulated ex vivo with bacterial lipopolysaccharide. Circulating numbers of CD14+/HLA-DR+ cells at 24 hours after the dose were increased in a dose-dependent manner. Effects on expression of HLA-DR by CD14+ cells were variable. There was no apparent effect on HLA-DR expression by CD20+ cells. The immunomodulatory effects of rhIL-10 merit further clinical investigation.     

Hematopoietic potential of cryopreserved and ex vivo manipulated umbilical cord blood progenitor cells evaluated in vitro and in vivo

The hematopoietic potential of cryopreserved and ex vivo manipulated umbilical cord blood (UCB) samples was evaluated in vitro and in vivo. Phenotypic analysis shows that approximately 1% of cord blood mononuclear cells express high levels of CD34 antigen on their surface (CD34hi), but none of a panel of lineage antigens (Lin-), suggesting that they are hematopoietic progenitor cells that have not yet committed to a specific lineage. Approximately 1% of CD34hi/Lin- cells are primitive hematopoietic progenitors that produce B lymphoid and multiple myeloid progeny for up to 7 weeks in stromal cell cultures. Twenty-one percent (+/- 13%) of CD34hi/Lin- cells also express low levels of the Thy-1 antigen and are threefold to fourfold enriched over CD34hi/Lin- cells in primitive hematopoietic potential as measured by long-term culture and phenotypic analysis. One-week liquid cultures of CD34-enriched UCB progenitor cells in the presence of interleukin (IL)- 3, IL-6, and stem cell factor (SCF) results in a two-fold to threefold expansion of progenitors capable of reinitiating long-term stromal cell cultures. Only the CD34hi/Thy-1+/Lin- cell population was capable of maintaining progenitors with secondary transfer potential in long-term stromal cell cultures and is thus postulated to contain all of the primitive hematopoietic stem cells in UCB. The in vivo transplantation potential of UCB was also measured. Ex vivo manipulated UCB progenitor cells were used to engraft irradiated human thymus fragments implanted in severe combined immunodeficiency (SCID) mice. Thymic engraftment with >5% donor-derived cells and a normal CD4/CD8 distribution was observed in 19 of 23 tissues tested. UCB cells from in vitro expansion cultures engrafted with efficiencies comparable to nonexpanded cells. Similar results were obtained for UCB engraftment of human bone fragments implanted in SCID mice. In all cases, engraftment was achieved in competition with endogenous competitor stem cells and across major histocompatibility barriers. Taken together, this data demonstrates that human UCB is a rich source of multipotent hematopoietic progenitors that can be cryopreserved, enriched by physical methods, and expanded in a limited fashion without measurable loss of long-term culture or in vivo engrafting potential as measured in these assays.     

Exposure of human CD34+ cells to human immunodeficiency virus type 1 does not influence their expansion and proliferation of hematopoietic progenitors in vitro

The susceptibility of highly purified human CD34+ cells to monocytotropic (Ba-L) and lymphotropic (A018-post) strains of human immunodeficiency virus-1 (HIV-1) was examined. Liquid cultures initiated with fresh immunomagnetically purified CD34+ cells using the K6.1 CD34 monoclonal antibody (MoAb) (K6.1/CD34+) were positive for HIV expression 2 weeks after exposure to HIV-1 Ba-L. These cells were initially greater than 90% CD34+ and had undetectable monocyte contamination by flow-cytometric staining and side-scatter analyses, respectively, and undetectable T-cell contamination by CD3 polymerase chain reaction (PCR) analysis. However, secondary CD34+ liquid cultures reselected from the primary liquid cultures 24 hours after HIV exposure by panning with the ICH3 CD34 MoAb (ICH3/CD34+) and maintained for an additional 14 days were negative for HIV expression. The ICH3-unbound cells were positive for both spliced and unspliced HIV RNA when exposed to HIV-1 Ba-L, and were DNA PCR positive when exposed to either monocytotropic or lymphotropic HIV-1. To further test that CD34+ cells were not infectible by HIV-1, we exposed K6.1/CD34+ cells continuously to HIV-1 in a culture system capable of maintaining and expanding primitive CD34+ cells. HIV-exposed K6.1/CD34+ cells proliferated and expanded as efficiently as uninfected cultures. However, when reselected magnetically using the K6.1 CD34 MoAb after expansion for 7 days, bound K6.1/CD34+ cells were again negative for HIV-1 expression, whereas unbound cells were positive for HIV-1 expression. These findings suggest that a sequential CD34+ cell-selection process, in which the two selections are separated by a brief culture period, can yield a population of CD34+ cells that are not infected with HIV-1. This process may be useful in the design of stem or progenitor cell- based transplantation therapies for HIV infection.     

A Cys374Tyr homozygous mutation of platelet glycoprotein IIIa (beta 3) in a Chinese patient with Glanzmann's thrombasthenia

A 20-year-old woman from a consanguineous family in the Hunan Province of the People's Republic of China was diagnosed as having Glanzmann's thrombasthenia based on (1) nearly a lifelong history of epistaxis, gum bleeding, petechiae, and purpura; (2) severe menorrhagia resulting in anemia and need for whole-blood transfusion; (3) normal coagulation assays; (4) prolonged bleeding time; (5) absent clot retraction; (6) decreased glass bead retention; (7) absent platelet aggregation in response to adenine diphosphate, epinephrine, and collagen; and (8) normal initial slope of platelet aggregation in response to ristocetin, but with a diminished maximal extent. The patient's platelets had a decreased level of platelet fibrinogen, but the deficiency was not as severe as in other Glanzmann's thrombasthenia patients. As judged by monoclonal antibody binding studies, surface glycoprotein (GP) IIb/IIIa (alpha IIb beta 3) expression was less than 15% of normal and alpha v beta 3 vitronectin receptor expression was 15% to 19% of normal, suggesting that the defect was in GPIIIa (beta 3). Immunoblotting of platelet lysates demonstrated decreased levels of GPIIb (approximately 30% to 35% of normal) and GPIIIa (approximately 10% of normal), and the GPIIb had undergone normal maturational processing into GPIIb heavy and light chains. Sequence analysis of the patient's GPIIIa RNA identified a G to A mutation at nucleotide 1219, predicting a Cys to Tyr substitution at residue 374. The patient's parents, who are first cousins, are asymptomatic and have only minor reductions in platelet aggregation. Direct sequencing of polymerase chain reaction-amplified cDNA and GPIIIa exon VIII indicated that the patient is homozygous and her parents are heterozygous for the mutation. Transient transfection studies in Chinese hamster ovary cells indicated that the mutation results in an 85% to 90% reduction in GPIIb/IIIa surface expression, but these cells retain the ability to mediate adhesion to immobilized fibrinogen. The relative preservation of platelet fibrinogen despite the very low level of platelet surface GPIIb/IIIa expression in this patient raises some interesting questions regarding the mechanism of fibrinogen uptake and the pathophysiology of Glanzmann's thrombasthenia.     

Mortality from colorectal and breast cancer in gastric-surgery patients

In a preliminary years at risk analysis of 5018 patients treated surgically for peptic ulcer at St. James Hospital, Balham, between 1940 and 1960, there was an increase in mortality from colorectal cancer 20 or more years after operation (1.6 fold;p<0.05) and an increase in mortality from breast cancer (4.0 fold;p<0.001). During the first 20 post-operative years there was an apparent decrease in mortality from both cancers (relative rate = 0.7 (NS) for colorectal and 0.5 (p<0.01), for breast cancer). The excess risk of colorectal cancer after a 20 year latency was almost entirely due to the 9.5 fold (p<0.001) excess risk in the 381 female gastric ulcer patients treated by Billroth I operation, and the 8.0 fold (p<0.05) excess mortality for the small group of 123 female patients who had vagotomy for duodenal ulcer. The apparent decreased risk during the first 20 post-operative years was entirely due to the 5-fold decrease (p<0.01) in risk in the 659 male patients treated by Billroth I surgery for gastric ulcer. The ratio of colon: rectal cancers was very much higher in gastric ulcer than in duodenal ulcer patients (5.6 compared to 1.8) and higher in females than in males (6.0 compared to 2.4). The excess risk of breast cancer after a 20 year latency was 4-fold in both gastric ulcer and duodenal ulcer patients. In duodenal ulcer patients the risk was greatest in those treated by vagotomy whilst in the gastric ulcer patients no treatment sub-groups had a statistically significant increase. During the first 20 post-operative years the apparent decrease in risk was entirely in the gastric ulcer patients. We conclude that the increased risk of colorectal cancer 20 years after gastric surgery is limited to females, and is mirrored by a decrease in males during the first 20 years. These sex differences were virtually limited to gastric ulcer patients. For breast cancer the increased risk after 20 years affects gastric ulcer and duodenal ulcer patients equally.     

Serum soluble IL-2 receptor as a tumor marker in patients with hairy cell leukemia

Activated T cells synthesize and express a cell membrane-bound receptor for interleukin-2 (IL-2) and have recently been shown to secrete a soluble form of the same receptor. Hairy cell leukemia is a chronic disorder caused by expansion of a clonal population of an unusual mononuclear cell of B cell origin. These cells have previously been shown to express an IL-2 receptor on the cell membrane. The sera of 26 patients with hairy cell leukemia were examined for the presence of a soluble IL-2 receptor before and during therapy with either recombinant interferon alpha-2a or 2'-deoxycoformycin. Before therapy, all patients had markedly elevated levels of this soluble IL-2 receptor ranging from five to 60 times the highest level observed in normal control sera. In individual patients changes in the level during therapy correlated well with clinical assessments of tumor response; levels fell to near the normal range in patients responding to therapy. Patients not responding to interferon alpha had no significant change in the soluble IL-2 receptor level. These results suggest that hairy cells secrete a soluble IL-2 receptor and that serial measurements of the level of this receptor in the serum can be used as a noninvasive means to assess disease response to therapy.