To reuse your circuit: the HME debate.

Heat and moisture exchangers (HMEs) have been used for more than 30 years for heat and moisture retention during general anesthesia. Studies about bacteriostatic vs nonbacteriostatic HMEs (BHMEs/NHMEs) have been conducted to assess their role in preventing bacterial transmission to the anesthesia breathing circuit; none have been done on anesthetized patients in the operating room. The present study adds to existing knowledge about the HME's ability to prevent transmission of bacteria, with implications for cost reduction resulting from reuse of anesthesia breathing circuits among patients. The chi 2 test revealed no statistically significant differences between groups in transmission of bacteria from endotracheal tube (ETT) to anesthesia breathing circuit (P = .48). However, both groups showed statistically significant differences between presence of bacteria in ETTs and anesthesia breathing circuits: Group 1, BHME (P < .005) and group 2, NHME (P < .005). Neither HME prevented contamination of the machine side of the circuit. These results support not reusing breathing circuits. Of 53 participants in group 2, 28 had positive ETT cultures with 7 showing transmission to anesthesia breathing circuit. Of 46 participants in group 1, 28 had positive ETT cultures with 9 showing transmission to anesthesia breathing circuit.

Timing of vaccination does not affect antibody response or survival after pneumococcal challenge in splenectomized rats.

BACKGROUND: Pneumococcal vaccination after splenectomy for trauma decreases the incidence of overwhelming postsplenectomy infection. The optimal timing of vaccination has not been established. This study was conducted to determine whether timing of vaccination after splenectomy affects antibody response or survival after pneumococcal challenge. METHODS: Sprague-Dawley rats were used for all experiments. Control rats (n=30) were divided into three equal groups and underwent splenectomy followed by sham vaccination 1, 7, or 42 days after splenectomy. Treated rats (n=66) were divided into three equal groups and underwent splenectomy followed by vaccination with polyvalent pneumococcal vaccine 1, 7, or 42 days after splenectomy. All rats then underwent intraperitoneal Streptococcus pneumoniae inoculation with the predetermined lethal dose for 50% of the population 10 days after vaccination. Rats were observed for a 72-hour period after inoculation, and mortality was recorded. Immunoglobulin G and immunoglobulin M antibody titers were determined before vaccination and before inoculation to determine antibody response. RESULTS: Mortality was greater in the control group than in the treatment group (21 of 30 [70%] vs. 2 of 64 [3%]; p < 0.01). There were no differences in mortality within either the control group (1 day, 6 of 10; 7 days, 7 of 10; 42 days, 8 of 10; p=0.62) or the treatment group (1 day, 0 of 21; 7 days, 0 of 21; 42 days, 2 of 22; p=0.14). Immunoglobulin G and immunoglobulin M antibody responses were greater in vaccinated than in nonvaccinated rats. There was no effect of timing of vaccination on antibody response. CONCLUSION: Pneumococcal vaccine reduces mortality from postsplenectomy infection. Timing of vaccination after splenectomy does not affect survival from a pneumococcal challenge or antibody response in rats. This study supports the practice of administering vaccine within 24 hours of splenectomy when vaccine cannot be administered before surgery.

Measles revaccination response in a school-age population.

Due to the dramatic upsurge in the incidence of measles, the American Academy of Pediatrics and the Immunization Practices Advisory Committee of the Centers for Disease Control revised their measles immunization policies in 1989 to include a routine two-dose schedule. The objectives of this study were the following: (1) determine the prevalence of immunologically measles-susceptible subjects in a previously vaccinated, school-age, military dependent population; and (2) assess risk factors to identify immunologically measles-susceptible subjects. Serum was collected just prior to measles revaccination and again 2 weeks later. Measles-specific IgG and IgM titers were determined by enzyme-linked immunosorbent assay. Immunologically measles-susceptible subjects constituted 9.8% of the population. The interval since previous measles vaccination was significantly related to pre- and postrevaccination IgG titers in a repeated-measures analysis of variance model. The magnitude of increase in IgG titer following revaccination and analysis of trend for proportions of measles-susceptible subjects were significantly related to the age of initial vaccination. This study supports continued measles revaccination; in addition, revaccination appears to be of greater value at 11 to 12 years of age than at 4 to 6 years of age.

Serological response to measles revaccination in a highly immunized military dependent adolescent population.

In the spring of 1986, there was a measles outbreak in the city of El Paso, Texas, with 92 cases reported to the City-County Health Department. Of those 92 cases, 31 (32%) occurred within a public high school's student population of 2524. A mass measles vaccination program was undertaken at that high school in order to limit the outbreak. The student enrollment included a military dependent population of 368 students. Despite documented histories of prior measles immunizations in this military dependent subgroup, three individuals contracted the disease. Since this subgroup of students represented a highly immunized adolescent population, it was of interest to serologically determine their immune status prior to and following reimmunization with the expectation that such a study would provide information relating to the level of "protective" immunity. Prevaccination and postvaccination sera were obtained from 95 students. Results of measuring anti-measles antibody activity by ELISA indicate that 13 (14%) students responded to revaccination and experienced a fourfold or greater rise in IgG antibody levels. There were no detectable IgM responses. All of the students who responded to revaccination produced an anamnestic response (IgG boost only). Since most of these individuals had received first immunizations at 15 months of age or older, these findings suggest that secondary vaccine failure (waning immunity) was responsible for the putative "lowered" immunity in these individuals, instead of primary vaccine failure (maternal antibody suppression). These findings support current recommendations for measles booster revaccination of school-age children and adolescents.

Salivary epidermal growth factor in patients with and without acid peptic disease.

Epidermal growth factor inhibits gastric acid secretion and has a cytoprotective effect on the upper gastrointestinal tract. This study was undertaken to determine whether patients with endoscopically proven active peptic ulcer disease have a salivary deficiency of human epidermal growth factor (hEGF), compared to patients with a normal esophagogastroduodenoscopy (EGD). Saliva was collected from fasting subjects prior to EGD. The levels of EGF were measured by radioimmunoassay. Statistical evaluation was performed by analysis of variant followed by Student's t test. The concentrations of the peptide were lower in patients with active peptic ulcer disease (3.1 +/- 0.54 ng/ml, mean +/- SE, n = 25) compared with normal subjects (4.9 +/- 0.56 ng/ml, n = 58, p less than 0.03). No significant differences in salivary hEGF were noted between patients with a normal EGD and patients with gastritis (3.85 +/- .86 ng/ml, n = 13), esophagitis (4.5 +/- 1.3 ng/ml, n = 7), or Barrett's esophagus (5.3 +/- 1.5 ng/ml, n = 6). There were no differences in the salivary levels of hEGF between males and females, or between smokers and nonsmokers. There was no correlation of hEGF levels with age. The pathophysiologic significance of this finding is uncertain. Lower salivary hEGF may reduce one of the defensive mechanisms responsible for protecting the gastroduodenal mucosa from injury by physicochemical agents, thus contributing to ulcer development.

Neutral and acidic human tracheobronchial mucin. Isolation and characterization of core protein.

Human bronchial mucin from a patient suffering from chronic bronchitis was solubilized in aqueous solution containing sodium azide and protease inhibitors and purified by Sepharose 4B and 2B column chromatography. The mucin was further purified by cesium bromide density gradient centrifugation. Sodium dodecyl sulfate-polyacrylamide gel (7.5%) electrophoresis of this material showed high-molecular-weight mucin component(s) at the top of the gel. Chemical analysis of this preparation indicated a typical mucin profile of amino acids and carbohydrates. Ion-exchange chromatography resulted in resolution of the purified mucin into neutral and acidic fractions. Comparison of the chemical composition of these two fractions showed higher mole percentage of threonine, serine, sialic acid, and sulfate in the acidic fraction. Chemical deglycosylation of the purified mucin preparation with trifluoromethane sulfonic acid was carried out at 20 degrees C for 3 1/2 h. Sialic acid, fucose, galactose, and N-acetylglucosamine were completely removed, whereas traces of N-acetylgalactosamine were still detected. High-pressure liquid chromatography of the deglycosylated products from native, neutral, and acidic mucin preparations resulted in a principal peptide, P1, with identical amino acid composition. Cyanogen bromide (CNBr) treatment of the peptide P1 from neutral and acidic mucins and subsequent fractionation of the fragments by high-pressure liquid chromatography resulted in similar peptide profiles. The P1 peptide fraction was further subjected to high-pressure liquid chromatography in a second solvent system, which resulted in two peaks, P1a and P1b. Gel filtration of both peptides in 6 M guanidine hydrochloride indicated a single peak with molecular weight of approximately 97 kDa. The amino acid profile of the two peptides was dominated by high levels of threonine, serine, and proline, which combined accounted for nearly 39% of the total residues, and in most respects, the profile resembled that of native mucin. End-group analysis of the peptide P1a indicated a blocked N-terminus, whereas serine was found to be the N-terminal amino acid in the peptide P1b. Rabbit antibodies prepared against the peptide P1 from native tracheal mucin reacted strongly with neutral and acidic mucin as well as the mucin from human colon. Both neutral and acidic human tracheal mucins were immunologically reactive with mouse monoclonal antibody HMPFG-2, which was prepared against human mammary mucin. However, the response of this antibody to human colonic mucin was rather weak.

[The effect of Campath-1 on T- and NK-cells]. / Wirkung von Campath-1 auf T- und NK-Zellen.

An assay system capable of detecting 0.03% residual T cells is described. This test system was used to evaluate bone marrow which was treated with Campath-1 and human complement (HC'). All T cell-depleted samples tested were found to be free of OKT3-positive T cells (less than 0.03%). The assay described provides a highly sensitive method for the detection of residual T cells and can be used as an alternative to limiting dilution assays. The results presented here confirm that treatment of donor bone marrow with Campath-1 and HC' provides a highly effective means of removing T cells and thus should be effective in GVHD prevention. However, although Campath-1 effectively depletes T- and B cells, it unexpectedly failed to eliminate cells that display NK function.

[Modulation of graft versus host disease by in vitro incubation of donor cells with deoxycoformycin and deoxyadenosine]. / Modulation der Graft-versus-host-Erkrankung durch In-vitro-Inkubation von Spenderzellen mit Deoxycoformycin und Deoxyadenosin.

The combination of deoxycoformycin and deoxyadenosine was investigated for its capability to deplete T-cells from bone marrow and spleen cells and for its effect on GVHD in MHC-mismatched transplantation in rats. In vitro incubation with DCF/dADO for 18-20 hours resulted in significant but incomplete T-cell depletion without toxicity towards CFU-M. This corresponded with a lower incidence and a modification of GVHD following transplantation of such treated cells into MHC-incompatible recipient rats. However, GVHD could not be completely prevented by the in vitro treatment of donor cells.

Effects of total body irradiation followed by bone marrow transplantation on the disposition kinetics of methotrexate in the rat.

The effects of total body irradiation followed by bone marrow transplantation on the disposition kinetics of intravenously-administered methotrexate have been studied in the Wistar-Furth rat. Eight test animals received total body irradiation (1000 rads) followed by intravenous administration of 3 X 10(8) bone marrow cells per kg body weight. Eight control animals were sham-irradiated and received an equal volume of blank suspension medium. One day after these treatments each rat received methotrexate (25 mg/kg) by rapid intravenous injection and serial blood samples were obtained over a 3 hour period. Serum methotrexate concentrations were measured by high performance liquid chromatography and pharmacokinetic parameters were calculated after NONLIN analysis of data. No significant differences were observed in total body clearances of test and control animals. As methotrexate in the rat is cleared predominantly by renal excretion of unchanged drug, these findings suggest that this process is not affected by radiation. Significantly larger volumes of distribution were observed in test animals. Increased extent of distribution in irradiated animals could be a result of a radiation-induced increase in membrane permeability and/or increased blood flow to irradiated areas. Future studies should assess the clinical significance of such findings.

Effects of total body irradiation followed by bone marrow transplantation on the disposition kinetics of mitomycin-C in the rat.

The effects of total body irradiation followed by bone marrow transplantation on the disposition kinetics of intravenously-administered mitomycin-C have been studied in the Wistar-Furth rat. Five test animals received total body irradiation (1000 rads) followed by intravenous administration of 3 X 10(8) bone marrow cells per kg body weight. Five control animals were sham-irradiated and received an equal volume of blank suspension medium. One day after these treatments, each rat received mitomycin-C (10 mg/kg) by rapid intravenous injection and serial blood samples were obtained. Serum mitomycin-C concentrations were measured by high performance liquid chromatography and pharmcokinetic parameters were calculated after NONLIN analysis of data. Smaller total body clearances in test animals were probably due to radiation-induced inhibition of microsomal enzyme activity. Reduced volumes of distribution were observed in test animals although the reason for this is unclear. Future studies should assess the clinical significance of these results.

Increased adenosine deaminase (ADA) activity and a shift from ADA-dependent to ADA-independent phases during T-cell activation: a paradox.

During activation of WF rat splenic T-cells, a change occurs with respect to susceptibility to a toxic accumulation of adenosine or deoxyadenosine (dADO) in the presence of adenosine deaminase (ADA) blockade. Addition of nucleoside 1 hour after the initiation of a concanavalin A response in the presence of 2'deoxycoformycin (DCF) markedly inhibited the response, whereas delay of addition of the nucleoside for 24-48 hours resulted in minimal or no inhibition. Inhibition was not simply the result of prolonged incubation of cells in the presence of nucleoside and was apparently not attributable to an effect on proliferating cells. Addition of interleukin 2 (IL-2) to cultures containing DCF and dADO did not reverse the inhibitory effect, which suggests that IL-2-producing T-cells also were not the target of nucleoside toxicity. A twofold increase in ADA activity that occurred during T-cell activation was nonessential for the survival of mitogen-activated T-cells in the presence of toxic concentrations of dADO and did not account for an apparent increased resistance of these cells to nucleoside toxicity. These paradoxical observations prompted an analysis of ADA activity in various populations of activated T-cells enriched with cells in G0/G1, S, or G2+M cell-cycle phases, which indicated that increased ADA activity was not associated with a specific period during cell-cycle traverse, but, rather, coincided with cell enlargement in preparation for mitosis. In conclusion, either an early event in T-cell mitogenesis is highly susceptible to nucleoside toxicity or a mechanism independent of ADA is acquired during T-cell activation that allows proliferating T-cells to resist toxic concentrations of nucleoside.

Identification and characterization of a human thymus-leukemia antigen (43-kDa/513TL) bearing a structural relationship to HLA.

A human thymus-leukemia-like antigen has been identified that is antigenically distinct from T6/HTA-1. This was accomplished with a rabbit antiserum (513) which was prepared against lymphoblasts that were E rosette negative (E-), human thymus antigen positive (HuTA+), cALLA-, DR-, SmIg- from a patient who presented with a mediastinal mass and a WBC count of 130 X 10(9) cells/1. Following absorption with B cell and "null" cell lines, 513 exhibited prominent reactivity with a membrane antigen that was present on normal thymocytes and lymphoblasts from 11 of 13 patients with T cell ALL and 1 of 16 patients with common ALL, but was not detected on normal peripheral blood lymphocytes, normal bone marrow cells and leukemic lymphoblasts with an undifferentiated phenotype. SDS-PAGE analysis of this antigen indicated that it was composed of two subunits, 43-kDa and 12-kDa. Sequential absorption experiments revealed that: (1) the 12-kDa subunit was antigenically similar to beta 2 microglobulin; (2) the intact molecule did not exhibit HLA-A, B or C "framework" determinants; (3) the molecule was antigenically distinct from a human thymus-leukemia antigen HTA-1 (recognized by monoclonal antibodies NA1/34 and OKT6); and (4) the molecule was antigenically distinct from adenosine deaminase. It is concluded that 513 reacts with a membrane protein (designated 513TL) which exhibits properties characteristic of a histocompatibility-like antigen whose expression is restricted to thymocytes and some leukemias (TL antigen). Its antigenic distinction from another recently characterized human TL antigen, HTA-1, suggests polymorphism among this family of alloantigens.

Identification and molecular characterization of macrophage-associated antigens of the rat.

Rabbit antiserum to rat peritoneal exudate (PE) macrophage (M phi) antigens was prepared and its reactivity with cell surface proteins of M phi, granulocytes, and lymphocytes was studied by one- and two-dimensional polyacrylamide gel electrophoresis (PAGE). A total of 14 membrane antigens were identified of which three were found to be expressed only by M phi and granulocytes. By one-dimensional analysis, a protein with an approximate m.w. of 105,000 was present on splenic and PE M phi and on splenic lymphocytes. Two-dimensional analysis revealed that this band was heterogeneous and contained at least three species, one of which was restricted to expression on M phi and granulocytes. A second protein of 150,000 daltons was resolved into two species by two-dimensional analysis. Both of these species were present on M phi and granulocytes but not on lymphocytes. Both the 105,000- and 150,000-dalton proteins were glycosylated. Because the 105,000- and 150-000-dalton proteins expressed by M phi were also expressed by granulocytes, is is likely that these are differentiation antigens whose expression is a characteristic property of cells within both monocytoid and myeloid lineages. All three 105,000-dalton species and one of the two 150,000-dalton species were detected on mouse M phi, indicating their expression is not unique to the rat.

Identification of a leukemia-associated antigen of human acute lymphocytic leukemia.

A human leukemia-associated antigen (LAA) has been identified by immunofluorescence and electrophoretic analyses. LAA was detected on the surfaces of cells from patients with acute lymphocytic leukemia (ALL) as well as on the surfaces of leukemia cells from the established cell lines NALM-1, NALM-16, MOLT-4, CCRF-CEM, and RPMI 8402. The antigen was not detected on BALM-1 or Raji cells (established B-cell lines), bone marrow cells from ALL patients in remission, or on blood lymphocytes from normal donors. This antigen was most frequently associated with common ALL (cALL); however, cells from 2 of 12 patients with T-cell ALL and 1 patient with B-cell ALL also expressed this antigen. Under reduced conditions, the antigen had an approximate molecular mass of 100,000 daltons as determined by sodium dodecyl sulfate--polyacrylamide gel electrophoresis and autoradiographic analysis and appeared to be the same cALL antigen that has recently been described by others. The probability that LAA is a normal differentiation antigen was discussed.

Genetic association of the humoral and cellular immune responses of rats to Moloney sarcomas.

Brown Norway (BN), Lewis (Le), F1 hybrids of LexBN (LBN) and parent-to-LBN backcross rats were tested for cellular and humoral responses to a BN Moloney sarcoma. Regardless of AgB phenotype, BN backcrosses produced low levels of cell-mediated cytotoxicity (CMC) that were comparable to those of BN parents. Le backcrosses developed high levels of CMC similar to those produced in Le parents. An inverse relationship between levels of CMC and serum antibodies (cytotoxic for tumor cells and anti-p30 of MuLV) was observed; BN parents and backcrosses produced high levels of serum antibodies whereas levels in Le parents and backcrosses were low. LBN hybrids developed relatively high levels of CMC and serum antibodies. An additional finding was that the CMC response in Le parents and back-crosses was directed primarily against tumor-associated antigens rather than histocompatability antigens expressed on the tumor cells. The results suggest that humoral and cellular responses to Moloney sarcoma in rats are not determined solely by the major AgB histocompatibility locus but do have a genetic association. This genetic association was detected with a 51Cr release assay which detects T-cells, suggesting that select populations of effector T-cells may be genetically regulated.