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While in the last decade there has been significant technical infrastructure development to support standards-based image exchange through organizations like Integrating the Healthcare Enterprise, Carequality, DICOM, and HL7 FHIR, the human operationalization of such infrastructure using centralized, intuitive, standards-based applications remains the cornerstone of effective and reliable electronic image exchange. Image libraries managing the highly transactional and often uncertain inflows and outflows of images have a unique perspective on the challenges of image exchange. This manuscript will summarize frequent collaboration and communication, release of information, staffing, technology, information localization, and analytics difficulties for image exchange from the perspective of the image library staff managing the transactions., (© 2022. The Author(s) under exclusive licence to Society for Imaging Informatics in Medicine.)

The consolidation of information technology (IT) teams from individual facilities to an enterprise-wide reporting structure and the transition of IT staff from operating within a diagnostic imaging department, such as Radiology, to an enterprise IT group is common. The plan to optimize this workforce can have undesirable and unintended consequences, if not done correctly. For those organizations seeking to optimize their workforce to deliver the best possible IT services, including to areas that produce and use medical imaging, this can be an exercise of balancing specialized knowledge and centralized staffing capacity planning. Successfully blending staff that have developed through careers in either general or imaging IT areas into a single team structure requires an understanding of their traditional attitudes, priorities, and skill sets. This paper explores the historic similarities and differences in the skill sets and work cultures between imaging and Enterprise IT, and how to use both to deliver the best outcomes., (© 2021. Society for Imaging Informatics in Medicine.)

This paper describes why and how DICOM, the standard that has been the basis for medical imaging interoperability around the world for several decades, has been extended into a full web technology-based standard, DICOMweb. At the turn of the century, healthcare embraced information technology, which created new problems and new opportunities for the medical imaging industry; at the same time, web technologies matured and began serving other domains well. This paper describes DICOMweb, how it extended the DICOM standard, and how DICOMweb can be applied to problems facing healthcare applications to address workflow and the changing healthcare climate.

Clinical specialties have widely varied needs for diagnostic image interpretation, and clinical image and video image consumption. Enterprise viewers are being deployed as part of electronic health record implementations to present the broad spectrum of clinical imaging and multimedia content created in routine medical practice today. This white paper will describe the enterprise viewer use cases, drivers of recent growth, technical considerations, functionality differences between enterprise and specialty viewers, and likely future states. This white paper is aimed at CMIOs and CIOs interested in optimizing the image-enablement of their electronic health record or those who may be struggling with the many clinical image viewers their enterprises may employ today.

This white paper explores the technical challenges and solutions for acquiring (capturing) and managing enterprise images, particularly those involving visible light applications. The types of acquisition devices used for various general-purpose photography and specialized applications including dermatology, endoscopy, and anatomic pathology are reviewed. The formats and standards used, and the associated metadata requirements and communication protocols for transfer and workflow are considered. Particular emphasis is placed on the importance of metadata capture in both order- and encounter-based workflow. The benefits of using DICOM to provide a standard means of recording and accessing both metadata and image and video data are considered, as is the role of IHE and FHIR.

Structured reporting, created when a standardized template with organized subheadings is combined with relevant observations of a diagnostic study into a meaningful result, has the potential to raise both the quality and the predictability of the radiologist report, revolutionizing the workflow and its outcomes. These templates contain great value, as they carve a path based on best practice for the radiologist to follow, and thus should be shared, reviewed, and improved. Unfortunately, these templates are often not shareable today due to a lack of standards for describing and transporting templates. This paper outlines and discusses an appropriate and effective electronic method for transporting radiology report templates using of the style of representational state transfer (REST). Enabling a structured radiology report template library with REST enables just-in-time accessibility of templates, achieving efficiencies and effectiveness.

A definite relationship is emerging between periodontal infections and systemic conditions. The objective of this review is to address this relationship as it pertains to cardiovascular disease and diabetes mellitus. Furthermore, because recent reports link the presence of periodontal disease to preterm delivery, the possible relationship between the development and progression of periodontal disease and certain hormonal states in women such as puberty, oral contraceptive use, menopause, and pregnancy will also be discussed. Although the current literature suggests a strong association between periodontal disease and a number of the discussed systemic conditions, causality can only be established with prospective studies. Intervention studies are needed to address how treatment effects the incidence and/or severity of periodontal disease-related systemic illness.

The purpose of this paper is to discuss a number of components associated with the design, development and conduct of a randomized clinical trial (RCT). In a RCT, a patient is entered into a protocol in which therapy is randomly assigned. Thus, neither the patient nor the care provider have active roles in deciding treatment. The elements of informed consent were developed to ensure that the patient's interests are protected. The informed consent document serves as the cornerstone of a clinical study by introducing patients to the research protocol, informing them of their role as participants in the study, and educating them of their rights. Questions regarding ethics arise during all phases of a study. A study designed with insufficient sample size will provide inconclusive data, thus making participation in the study of limited to no value. Conversely, having patients enrolled in a RCT after data has proved superiority of an arm of the study postpones beneficial therapy for patients and society. Other ethical conflicts arise when subjects are recruited for clinical trials. Special care must be taken to avoid coercion in protected populations such as students, employees, the mentally challenged, and the indigent. Careful planning with adequate attention to consent from development can minimize problems and optimize patient care and research integrity.

Ethical justification for starting a clinical trial requires at the outset an accurate statement of "no difference" regarding the two or more agents to be compared. This may be expressed as "theoretical equipoise" (no data to support the superiority of one of the agents) or, preferably, as "clinical equipoise" (there are insufficient data to resolve controversy among experts as to which is superior). This presents a problem when a placebo control is proposed, particularly when the outcome measure entails irreversible loss of function; preliminary data often suggest the superiority of the "active agent." Informed consent should ordinarily include the fact that treatment assignments will be accomplished by a process of randomization and, in the case of double-blind designs, that neither the subject nor the investigator will know the subject's treatment assignment until the end of the trial. In general, clinical trials should be monitored by data and safety monitoring boards that have access to unblinded data; they should be guided by stopping rules that should be agreed upon by all concerned before the trial is begun. Women and minorities must be included unless there is strong justification for their exclusion. Care must be taken to balance the competing objectives of validity (the results will be correct), generalizability (the results will be broadly applicable), and efficiency (the study will not be unduly expensive).

The mechanism of activity and the antiviral spectrum of Listerine antiseptic have not been examined thoroughly. We therefore tested its effect on laboratory strains of herpes simplex type 1 and type 2 (enveloped DNA viruses), influenza A virus (enveloped RNA virus), rotavirus (nonenveloped RNA virus), and adenovirus type 5 (nonenveloped DNA virus). Each virus was mixed with an equal volume of Listerine for 30 seconds to 5 minutes, and the residual infectivity of the virus was assessed. An antiviral effect was defined as greater than 95% reduction of infectivity. Exposure to Listerine for 30 seconds had an antiviral effect against herpes simplex type-1 and type-2 (96.3% and 100% reduction in infectious virus, respectively) and influenza A (100% reduction). In contrast, rotavirus-induced plaque formation was reduced by 12.2% after 30 seconds of exposure to Listerine, whereas 5 minutes of exposure to Listerine resulted in a 21.5% increase in plaque formation. Exposure of adenovirus to Listerine had a minimal effect on the cytopathocity of the virus, with a 33.4% reduction in virus levels after 5 minutes. The antiviral activity of Listerine is thus not related to the viral genome but is probably directed to the viral envelope.

The relationship between implant surfaces and decontamination treatments was studied in vitro to determine which implant surfaces were most effectively decontaminated, and which treatment was most effective for treating a particular implant surface. The implants used in the study were press fit cylindrical titanium units with machined, plasma sprayed, and hydroxyapatite-coated surfaces. Radioactive endotoxin (125I-LPS) was prepared from Porphyromonas gingivalis (ATCC 33277). Implants were coated with 125I-LPS and treated by burnishing with a cotton pellet soaked in water, citric acid solution (CA), or 0.12% chlorhexidine (CHX); or treated with an air-powder abrasive (AIR). Radioactivity was determined after each of two treatment cycles. The results for each implant surface were analyzed using ANOVA to determine differences between treatments. The remaining 125I-LPS after two treatment cycles were: for machined implants AIR < CA, with AIR = water = CHX and water = CHX = CA; for plasma sprayed implants AIR < water = CHX = CA; for hydroxyapatite implants AIR = CA < water < CHX. In evaluating treatment modalities, it was found that machined implants were decontaminated more effectively than the other surfaces by all treatments; the exception was citric acid treatment which was equally effective on either machined or hydroxyapatite surfaces. These results indicate that machined implants (without surface coating) are most readily decontaminated by a variety of methods; this characteristic should be considered, since long-term success of implants may involve treating periimplantitis. Further, the results indicate that air abrasives are effective for decontaminating implant surface, with the exception that hydroxyapatite coated surfaces can be treated equally with air abrasives or citric acid.

Regeneration of periodontal tissues requires orchestration of several cell types. Two cell types, gingival fibroblastic cells (gingival fibroblasts) and cells from the periodontal ligament (PDL cells), were studied to compare the effects of supplemental addition of TGF-beta 1 and PDGF on proliferation. Cells obtained from healthy donors were cultured in 10% FBS supplemented with either 10 ng/ml TGF-beta 1, 20 ng/ml PDGF, or both. Thymidine incorporation was measured after 24, 48, or 72 hours. Data from PDL (analyzed by ANOVA) showed the following relations: at 24 hours TGF beta 1/PDGF = PDGF > TGF-beta 1 = control; at 48 hours TGF beta 1/PDGF > TGF-beta 1 > PDGF > control; at 72 hours TGF beta 1/PDGF > TGF-beta 1 > PDGF = control. Gingival fibroblast cultures showed the following relations: at 24 and 48 hours TGF beta 1/PDGF = PDGF > TGF-beta 1 = control; at 72 hours, TGF beta 1/PDGF = PDGF > control with TGF beta 1 not different from control or factor combinations. Both TGF-beta 1 and TGF-beta 1/PDGF showed a significantly greater increase in proliferation of PDL cells than in gingival fibroblasts at 48 and 72 hours (Student t test P < 0.05). In contrast, PDGF stimulated proliferation of gingival fibroblasts was significantly greater than PDL cells at 72 hours (P < 0.05). Thus, supplementation of complete cultures (containing 10% FBS) with TGF-beta 1 alone or combined with PDGF stimulates proliferation of PDL cells to a significantly greater extent than proliferation of gingival fibroblasts.(ABSTRACT TRUNCATED AT 250 WORDS)

An increase in functional sarcolemmal Na(+)-K(+)-ATPase (Na+ pump) precedes proliferation in vascular smooth muscle cells (VSMCs) seeded in 10% fetal bovine serum (FBS), but its role in mitogenesis is unresolved. Enzymatically dispersed canine coronary artery VSMCs were seeded in FBS and studied through confluence. Before a shift in cell cycle (G1-->S, G2 + M) and appearance of the nonmuscle isoform of myosin (MHCnm), intracellular Na+ content (Na+i) and cell volume (CV) increased (day 0 through day 3). Na+ pump number ([3H]-ouabain binding) increased at day 4 followed by a decrease in Na+i and CV. When Na+ pumps were inhibited by the addition of ouabain to FBS, VSMCs were arrested in G1, and MHCnm was not upregulated. Na+i increased similarly to that in FBS but failed to correct to day 0 levels. Withdrawal of ouabain at day 4 in culture led to an increase in Na+ pump number, a decrease in Na+i, entry of cells into S and G2 + M, and upregulation of MHCnm. These data suggest that Na+i, phenotypic modulation, and entry of cells into the cell cycle are temporally related, with Na+ pump-mediated correction of increased Na+i as a key event in the VSMC mitogenic process.

Compromised neutrophil function has been found in a number of patients with localized juvenile periodontitis (LJP), although the pathogenic mechanism is unknown. Since infection with Actinobacillus actinomycetemcomitans is frequently found in patients with LJP, we have evaluated in vitro the effect of a bacterial extract of A. actinomycetemcomitans on the development of the respiratory burst by neutrophils. Pre-incubation of neutrophils with bacterial extract increased H2O2 induced by FMLP and zymosan in a dose-dependent fashion. Substitution of FMLP for bacterial extract produced similar results. Moreover, FMLP and bacterial extract had an additive effect on superoxide production following phagocytosis of zymosan. In contrast, bacterial extract significantly decreased PMA-stimulated H2O2, but pre-incubation with FMLP instead of bacterial extract failed to decrease PMA-stimulated H2O2. Bacterial extract did not change the percentage of cells activated by FMLP, opsonized zymosan, or PMA. Heat-treated bacterial extract induced effects similar to non-treated extract. Bacterial extract treated with proteinase K or phenol extraction increased FMLP or zymosan stimulated H2O2 equivalent to non-treated bacterial extract. In contrast, proteinase K or phenol extraction abolished the inhibitory effect of bacterial extract on PMA-stimulated H2O2 production. The bacterial extract component(s) that inhibits PMA-stimulated H2O2 is therefore a protein(s), resistant to 56 degrees C, and is not endotoxin. The partially activated state of PMNs exposed to A. actinomycetemcomitans extract, combined with their reduced ability to respond to a protein kinase C-dependent stimulus, may partially explain the abnormalities noted in LJP patients.

Localized juvenile periodontitis is an early onset periodontitis, usually localized to molars and incisors. Patients usually present with decreased chemotaxis of systemic neutrophils (PMNs) and infection with Actinobacillus actinomycetemcomitans. The pathogenic mechanisms involved have not been clarified. The purpose of this study was to determine if an extract of A. actinomycetemcomitans could induce changes in PMN chemotaxis similar to those reported in LJP patients. It was demonstrated that the bacterial extract was chemotactic for neutrophils. When neutrophils were pre-incubated with the bacterial extract, chemotaxis toward zymosan-activated serum, FMLP and the bacterial extract was inhibited in two different chemotaxis assays (Boyden chamber and under-agarose). Bacterial extract had no effect on random migration in either assay. Pre-incubation with the extract induced increased expression of CD11b/CD18 (Mac-1), Gp110, and FMLP receptors and increased F-actin polymerization following FMLP or PMA stimulation compared to cells not treated with the extract. Treatment of the bacterial extract with proteinase K or phenol extraction reversed the PMN chemotaxis inhibition activity, but increased significantly the random migration of PMNs. Heating the bacterial extract to 56 degrees C had no effect on its activity. The component(s) in the bacterial extract that inhibits chemotaxis is therefore a protein(s), not sensitive to 56 degrees C, and is not endotoxin. This study suggests that A. actinomycetemcomitans may contribute to the pathogenesis of localized juvenile periodontitis by inhibiting chemotaxis. Interference with chemotaxis by A. actinomycetemcomitans, however, occurs through a mechanism other than inhibition of actin assembly, reduction of CD11b/CD18 or Gp110 expression, or blockage/downregulation of FMLP receptors.

Generation of cytotoxic T lymphocytes (CTL) in mixed leukocyte cultures was suppressed by a factor elaborated by alloantigen-activated T cells. This suppressor factor, CTL-TsF, in contrast to a factor that suppresses proliferative responses in mixed leukocyte reactions (MLR-TsF), was effective only when added during the first 24 hr of a 6-day-culture period. Moreover, removal of CTL-TsF 24 hr after culture initiation failed to restore CTL responses. CTL activity could be rescued from suppressed cultures, however, by addition of 2-mercaptoethanol on days 3 or 4. Similarly, transfer of nonadherent cells at 3 or 4 days from cultures treated with CTL-TsF to cultures of adherent cells initiated in control factor restored CTL responses. Mixing experiments with cells pulsed with CTL-TsF for 4 hr at culture initiation identified a target of CTL-TsF as a Thy-1 negative cell that was adherent to plastic and to Sephadex G-10. Suppression was not due to interference with physiologic accessory cell function, but more likely was accomplished via a negative signal from CTL-TsF-pulsed cells. The results thus suggest that CTL-TsF acts early, but reversibly, in the CTL differentiative process via a second suppressor effector cell, possibly a macrophage.

The lymphocytes of two unrelated black individuals exhibited no immunofluorescent staining by a monoclonal antibody, OKT4, that reacts with T helper/inducer cells, but the lymphocytes reacted normally with four other monoclonal antibodies that identify T helper cells. Four first-degree relatives of these individuals were available for study. They had a normal proportion of OKT4+ lymphocytes but these cells had approximately half the normal number of OKT4 sites. This abnormality appears to be inherited as an autosomal recessive state.

The purposes of this study were to develop a new method for isolating salivary neutrophils (SPMNs), and to determine their functional activity. Studies of neutrophils in the oral cavity have been largely limited to crevicular PMNs, because of difficulties in obtaining viable SPMNs free of epithelial cells. A method to obtain SPMNs is presented. Donors performed rapid sequential rinsings by placing in their mouths 15 mL of Hanks' balanced salt solution [free of calcium or magnesium ions (HBSS-CMF)], which contained 0.1% gelatin, then swishing the solution for 30 s, and expectorating into a polypropylene receptacle containing 400 mL 4 degrees C HBSS-CMF. This sequence was repeated for 20 min. The collected solution was stirred for 10 min, the cells were washed, and the re-suspended pellet was passed sequentially through a 20-microns and a 10-microns nylon mesh. The cells consisted of 97.7 +/- 1.7% SPMNs, only 2.3% epithelial cells, and were almost free of oral debris. The SPMNs were studied for CD11b expression, H2O2 production, and F-actin polymerization. SPMNs had significantly higher resting values for CD11b, H2O2 production, and F-actin polymerization compared with blood neutrophils (BPMNs). SPMNs responded to stimulation by chemotactic peptide or phorbol ester in a dose-dependent fashion, with levels of CD11b, H2O2, and F-actin comparable with BPMNs at optimal stimulant concentrations. The elevated resting levels of CD11b, H2O2, and F-actin for SPMNs were probably caused by exposure to gingival and oral bacteria.(ABSTRACT TRUNCATED AT 250 WORDS)

Lymphocytes were isolated from human colostrum and peripheral blood collected within 7 days postpartum. A 20-fold enrichment of lymphocytes from colostrum was achieved by centrifugal elutriation followed by equilibrium density gradient centrifugation. The distribution of T lymphocyte subsets was determined by immunofluorescence analysis of reactivity with monoclonal antibodies of the OKT series. In confirmation of previous reports employing sheep erythrocyte rosette assays, the majority of colostral lymphocytes reacted with OKT3 monoclonal antibody, a reagent that detects a surface antigen on mature T cells. Neither colostral nor blood lymphocytes from postpartum donors expressed the OKT6 antigen that is found in immature thymocytes. A novel finding is that the T lymphocyte population in colostrum contains both OKT4 (helper/inducer phenotype) and OKT8- (cytotoxic/suppressor phenotype) positive subsets. The relative ratio of OKT4 to OKT8-positive T cell subsets in colostrum, however, is generally lower than that observed for peripheral blood T cells.

Human monocytic cell line THP-1 incubated with as little as 10 ng/ml of phorbol myristate acetate bound and metabolized 1-2 micrograms of Ac-LDL over a 5-h period. In the absence of phorbol treatment, no specific metabolism of Ac-LDL occurred. Optimal levels of receptor were reached after 72 h of exposure. Induction of receptor was dependent on protein and RNA synthesis and was partially reversed upon removal of the phorbol. Induction of receptor required activation of the protein kinase C pathway. Metabolism of Ac-LDL by THP-1 cells at 37 degrees C was saturated at 25 micrograms/ml. Binding at 4 degrees C was saturable with an average Kd of 8.0 x 10(-9) M. Cell population studies by fluorescent activated cell sorting indicated that approximately 87% of the THP-1 population was expressing scavenger receptor activity 96 h after phorbol treatment as compared to 99% for murine macrophage cell line P388D1. Uptake of Ac-LDL by THP-1 resulted in an 11-fold increase in the rate of cholesterol esterification which was saturable at 50 micrograms/ml. Incubation of cells for 48 h with 50 micrograms/ml of Ac-LDL resulted in a 60% increase in free cholesterol and a 10-fold increase in the cholesteryl ester content of the cells. Lipid accumulation in THP-1 cells after Ac-LDL uptake was readily visible by Oil Red-O staining. Solubilization of THP-1 cells, before and after phorbol treatment, followed by ligand blotting with Ac-LDL detected the presence of a 250-kDa protein only in cells treated with phorbol. The protein comigrated with the scavenger receptor derived from mouse macrophage cell line P388D1.

Enzymatically dispersed cells from canine saphenous vein and femoral artery were grown in fetal calf serum and studied at day 0 (freshly dispersed) through confluence in primary culture. Intracellular Na levels (Nai), but not intracellular K (Ki), were increased after 24 h in culture and then decreased to a steady state by 4 days. Na+ pump site number [( 3H] ouabain binding) increased through day 3 and remained elevated. Nai was still elevated at 2 days when the Na+ pump site number began to increase. Total pump turnover (maximum ouabain-inhibited 86Rb uptake) reflected the increase in Na+ pump site number. These key events precede the observed increases in both protein production and cellular proliferation. If the same cells are maintained in defined medium, without fetal calf serum, Nai, Ki, and the number of [3H]ouabain binding sites do not change with time. These data are consistent with the suggestion that the initial mitogenic response of vascular smooth muscle cells to fetal calf serum involves an increased Na+ influx, and a Nai accumulation, caused by low Na+ pump density. The synthesis of new pump sites effects a decrease in the accumulated Nai, which may be related to cell proliferation.

Primary cultures of canine saphenous vein smooth muscle cells downregulate the expression of the two muscle myosin heavy chains (mMHC) and upregulate the expression of a nonmuscle myosin heavy chain (nmMHC) when maintained in medium containing 10% fetal calf serum (FCS). The cellular function and control of these changes in contractile protein expression are not known. The purposes of these experiments were to determine whether the expression of nmMHC was required for cytokinesis, whether cell attachment stimulated nmMHC expression, and whether during changes in total myosin production the relative amounts of the two mMHCs remained constant. Primary cultures were maintained in FCS, in a serum-free defined medium (SFM), or after 2 days in SFM switched to FCS to induce proliferation and changes in myosin expression. nmMHC expression occurred before cytokinesis if cells were placed directly in FCS, whereas it occurred after cytokinesis if growth-arrested cells were exposed to FCS. The position of the cell in the cell cycle was responsible for these differences, and the temporal correlation of cell-cycle progression and nmMHC expression indicated that expression occurred during G1. Cells that remained unattached in the presence of FCS or attached in SFM did not express nmMHC. During net production or loss of mMHC by growth in SFM or FCS, respectively, the relative amounts of the two mMHC remained constant. These results suggest that 1) the expression of nmMHC requires the combined effect of FCS and attachment, 2) it occurs in cells progressing through G1 but is not required for cytokinesis, and 3) during changes in net myosin production, the two mMHC are coregulated.

In an attempt to identify the factors which might affect the measurement of water proton relaxation times in cultured cells, we have begun a long-term study of two human breast cancer cell lines, MDA-MB-231 and MDA-MB-435s. We tested growth rates and cell cycle distribution as intrinsic properties of the cells as well as methodological steps which might affect the measurement of T1 and T2. A detailed examination of the growth rates of the two cell lines, easily recognized as slow (231) and fast (435s) in culture, revealed that this attribute is difficult to correlate precisely with T1s or T2s. The reason is that the relaxation times are necessarily measured at one point in time while the growth rates are a summation of ongoing processes occurring over hours. Cell cycle distribution, on the other hand, can be measured simultaneously with the relaxation times by using cells quick-frozen from the same suspension. By this method, cell cycle distribution appears to be reflected through an effect on T1s. For example, cell pellets distributed 72:15:14 in G0G1:S:G2M has longer T1s (p less than 0.01) than those distributed 43:34:23 in G0G1:S:G2M. Regarding methodological factors, trypsin appeared to lower water content and T2s in the 231 cell line. Drift in the cell cycle distribution after sample preparation did not become significant until after 2 hours in the NMR tube. It was important to standardize the force and duration of centrifugation of the cell pellets to minimize the contribution of the suspending medium without affecting cell viability. We conclude that, given careful control of methodological factors, differences in T1 may reflect metabolic differences as demonstrated by T1 differences in cell pellets showing divergent cell cycle distribution.

DA (Ag-B4) rats were grafted with allogeneic Lewis (Ag-B1) skin on the region of the thorax drained by the left brachial and axillary lymph nodes. A DA isograft was placed on the right side of the thorax. From 1 to 14 days after grafting the rats were either given injections of colloidal carbon, killed, and spleen and lymph nodes were assayed for noncarbon-containing Fc rosette-forming leukocytes (RFL), or allowed to complete rejection of the graft. In order to assess secondary allograft rejection within the latter animals after the grafted areas was healed, a second Lewis allograft was placed in the same region as the first and another DA isograft on the right side. Compartmental Fc RFL were enumerated 2 to 16 days thereafter by rosette formation with erythrocyte-antibody. The regional lymph nodes of animals rejecting a primary allograft exhibited a significantly (P less than 0.05) higher level of Fc RFL compared with their contralateral controls. These higher levels were evident on days 6 to 8 and disappear by day 10. However, animals undergoing a secondary allograft response exhibited significant differences by day 4. A greater density of Fc RFL were also evident in cryostat sections of the graft bed of allografts as opposed to isografts.

The technique of flow microfluorometry has been extended to the study of small lipid complexes to assess either the lipid (hydrophobic) or aqueous (hydrophilic) compartments of selected natural or model membrane systems. sn-1-Palmitoyl-sn-2-oleoyl-phosphatidylcholine/cholesterol unilamellar vesicles, averaging 268 nm in diameter and containing varying concentrations of the synthetic lipophile probe, sn-1-palmitoyl-sn-2-12-[N-4-nitrobenzo-2-oxa-1,3- diazole]-aminocaproyl-phosphatidylcholine (NBD-PC), were analyzed using an Ortho Series 50-H Cytofluorograf and an Ortho 2150 computer system. NBD-labeled vesicles were analyzed for green fluorescence and the intensity of scattered light, the later being analyzed both at low angle (2-5 degrees) and at 90 degrees to the incident beam. At the high amplification required for vesicle detection, background signals from the sheath buffer, nonspecific laser light, and electronic noise were observed. However, this background noise signal was removed by appropriately setting a discriminator window. Profiles of signals falling within this region were then constructed. For the settings selected, more than 98% of data recorded could be attributed to observations on vesicles. Size information from the intensity of scattered light was obtained by comparison of the sample with fluorescent microspheres after correcting for the particle-scattering function difference between hollow and solid spheres and for refractive index differences. Additionally, cytograms and profiles were constructed for vesicles containing 5 mM 6-carboxyfluorescein, 3',6'-dihydroxy-3-oxospiro(isobenzofuran-1(3H),9'-(9H)xan then)-6-carboxylic acid, trapped in the aqueous core. Thus, the utility of flow microfluorometry has been extended to much smaller particle populations than studied previously by this technique.(ABSTRACT TRUNCATED AT 250 WORDS)

When murine spleen cells, alloantigen-sensitized previously in vivo, are incubated with spleen cells bearing the sensitizing alloantigens, a supernatant factor is produced that inhibits 3H-thymidine incorporation by responding lymphocytes in the mixed leukocyte reaction. This study evaluates the cellular and antigenic requirements during restimulation for elaboration of this suppressor factor, MLR-TsF. BALB/c spleen cells, sensitized to C57BL/6 (B6) alloantigens in vivo, produced MLR-TsF when cultured with B6 spleen cells in vitro, despite depletion of Sephadex G-10-adherent cells from factor-producing cells, stimulator cells, or from both populations. T cells were not required within the stimulating population, but a requirement for viable stimulator cells was demonstrated when heat-killed or glutaraldehyde-fixed stimulator cells failed to induce MLR-TsF production. The alloantigenic requirements for MLR-TsF production were addressed by 2 approaches. Treatment of stimulator cells with appropriate anti-I region antisera and complement did not affect MLR-TsF production, demonstrating that an absolute requirement for cells expressing I region determinants did not exist. However, spleen cells primed against entire H-2 haplotype differences produced significant quantities of MLR-TsF when they were restimulated with spleen cells homologous to the priming cells in only the I region, in the K and D regions, or in the D region alone. The additive nature of subregion-specific restimulation suggests that distinct subpopulations of K, I, and D region-specific MLR-Ts comprise the MLR-Ts population primed to entire H-2 haplotype differences.