Quantitation of solid-phase immunoassays using a fibre-optic reflectance spectrophotometer

A reflectance measuring instrument (fibre-optic spectrometer linked to a personal computer) which will quantitate the results of immunoassays that result in the deposition of a coloured chromophore on a membrane or other similar solid phase (SP) is described and the reflectance spectra of some chromophores which are commonly produced or used in SP immunoassays are presented. The instrument has been used in conjunction with silver-enhanced SP-immunogold capture assays to determine the concentrations in serum of IgG and of IgM rheumatoid factor (RF) and the results have been compared with those obtained by rate nephelometry and latex agglutination assays, respectively. It is concluded that fibre-optic reflectance photometry is an accurate and useful means of quantitating SP immunoassays in which coloured chromophores are produced and that the results obtained from such immunoassays are comparable to those given by established procedures.

Biological and clinical effects of intravenous tumor necrosis factor-alpha administered three times weekly

Tumor necrosis factor (TNF) is a cytokine with pleiotropic biological and antitumor effects in vitro and in mouse models. The immunological effects of the molecule as a single agent, however, have not been well studied clinically. We conducted a Phase I trial of TNF in 53 patients with advanced malignancies in order to determine the biological and clinical effects of TNF when administered as a 30-min i.v. infusion three times/week. Dose levels of TNF ranged from 5 to 275 micrograms/m2; doses of TNF were escalated between patient groups. The most common clinical toxicities of TNF consisted of rigors, anorexia, headache, and fatigue. Dose-limiting toxicity consisted of hypotension, fatigue, and nausea. Four patients treated at the maximally tolerated dose of 225 micrograms/m2 received dexamethasone to determine whether the toxicities of TNF could be ameliorated. No significant differences in hypotension or subjective symptomatology were observed in those patients receiving dexamethasone and those who did not or between injections in which dexamethasone was administered and when it was not. One patient with colorectal carcinoma treated with 50 micrograms/m2 had a partial response lasting about 9 months. Biological responses were evaluated in 8 patients treated at the maximally tolerated dose before therapy and 24 h afterward. TNF significantly (P less than 0.05 for all) enhanced serum beta 2-microglobulin, serum neopterin, and serum interleukin-2 receptor (Tac antigen) levels. Indoleamine 2,3-dioxygenase activity was also increased 24 h following the administration of TNF, although this increase was only of borderline statistical significance (P = 0.07). TNF did not enhance granulocyte bactericidal activity. The expression of cell surface proteins on monocytes, including HLA-DR, HLA-DQ, beta 2-microglobulin, and the Fc receptor, and serum interleukin-1 activity also were not significantly increased by the administration of TNF. Thus, in humans TNF caused biological response modulation with evidence of HLA Class I (beta 2-microglobulin) increase and T-cell (Tac antigen) and monocyte (neopterin) activation.

Nonsteroidal anti-inflammatory drugs and peptic ulcer disease

Evidence has accumulated that nonsteroidal anti-inflammatory drugs (NSAIDs) cause clinically important gastroduodenal ulcers. The pathogenesis, which involves the impairment of mucosal resistance to injury in an acid-peptic environment, is multifactorial and controversial. Ulcers caused by NSAIDs can occur either in mucosa inflamed because of infection with Helicobacter pylori or in histologically normal mucosa. The use of these drugs has been linked to an unexpectedly high incidence of ulcer complications, and a history of peptic ulcer disease is common in such cases. Nonsteroidal anti-inflammatory drugs thus appear both to exacerbate an underlying peptic diathesis and to cause de novo ulcers. The association between the use of these drugs and ulcer complications is supported by ulcer prevalence data from cross-sectional studies, and by data from case-controlled and cohort studies, and from randomized, experimental trials. Drug-induced gastric ulcers have been prevented by misoprostol, but not by H2 blocker therapy. Several therapies have been reported to promote ulcer healing despite continued use of NSAIDs, but adequate controlled trials have not been done. Small gastric and duodenal ulcers readily heal, whereas larger gastric ulcers require vigorous and prolonged therapy. The relative efficacies of various therapies in preventing ulcers, healing ulcers, or preventing complications remain to be established.

Successful cryopreservation of human bone marrow does not require a controlled-rate freezer

We studied CFU-GM recovery from bone marrow samples frozen either in a machine for controlled-rate freezing or in a -70 degrees C freezer. We found no statistically significant difference between the two methods. Cooling-curve investigations also demonstrated that it was possible to obtain satisfactory cooling rates simply by manipulation of the shape and volume of the marrow and its container. Five patients received a total of six successful autografts for which their marrow cells were frozen without controlled-rate freezing. Thus it is not necessary to use a sophisticated machine in order to obtain satisfactory cryopreservation of human marrow stem cells.

Bone marrow transplantation for genetic disorders

In 1967, a congenital disorder, severe combined immune deficiency disease, (SCID), was the first condition to be successfully corrected by bone marrow transplantation (BMT) from a histocompatible matched sibling donor. Since then the number of inherited disorders in which BMT has been used has been greatly extended. In preface, it should be stressed that BMT represents only one aspect of the management of genetic disorders which includes first and foremost detection and prevention by antenatal screening. Enzyme replacement treatment and the development of genetic engineering techniques to correct the underlying fault are being actively explored. However, reliable screening programmes are only feasible in a minority of disorders, of which thalassaemia is an example. Enzyme replacement treatment has been largely unsuccessful, and despite considerable advances in the understanding of gene regulation, at present BMT represents the only practice capable of correcting genetic disorders and improving the quality of life of affected individuals.

Improved plasmid shuttle vectors for Haemophilus influenzae and Escherichia coli

In vitro deletion and transposon mutagenesis experiments were performed to localize the region essential for plasmid RSF0885 replication to a 1.7-kb sequence downstream from the beta-lactamase gene. This locus was named rep, for replication. Plasmid RSF0885 can replicate in both Haemophilus influenzae and Escherichia coli. Replication in E. coli depended on transcription run-off from the beta-lactamase promoter into the rep locus. Insufficient transcription into the rep locus could account for the instability of this plasmid in an E. coli background, a property which reduced its usefulness as a shuttle vector. Therefore, four improved shuttle vectors for H. influenzae and E. coli were constructed. They possess the Co1E1 replication origin for maintenance in E. coli and the plasmid RSF0885 rep locus for maintenance in H. influenzae. Together, they provide twelve unique restriction sites for cloning by insertional inactivation of drug-resistance genes.

Interleukin-2 inhibits growth of fibroblasts derived from human bone marrow

The adherent layer that forms in human bone marrow suspension cultures contains fibroblast colonies which arise from colony-forming cells (CFU-F). We have demonstrated that recombinant interleukin-2 (r-IL2) inhibits growth of CFU-F by preventing their entry into S phase. This inhibition is not mediated by gamma-interferon, nor by T lymphocytes, and can be abrogated by anti-IL2 receptor antibody. r-IL2 may influence haematopoiesis by its effect on bone marrow CFU-F.

Infusion of vincristine and doxorubicin with oral dexamethasone as first-line therapy for multiple myeloma

32 previously untreated patients with multiple myeloma received vincristine, doxorubicin ('Adriamycin'), and dexamethasone (VAD) as first-line therapy. The overall response rate was 84%, with 28% of all patients entering complete remission. Response was rapid, with near-maximum response occurring after two courses of treatment and rapid improvement in bone-marrow function. Median response duration was 18 months and this seemed to be unaffected by initial prognostic criteria or by degree of remission achieved. The projected median survival was 44 months, with 75% of all patients and 83% of responders being alive at 2 years. Side-effects due to steroids were common, but there was only 1 treatment-related death. The high response rate and lack of toxicity offer an advantage over other forms of initial treatment, although other strategies will be necessary to prolong the duration of response.

Heat-induced aggregated human IgG modifies the adherence of human polymorphonuclear cells to cultured endothelium

The adherence of human blood polymorphonuclear cells (PMNC) to cultured porcine aortic endothelium was enhanced by high concentrations of heat-stable IgG aggregates (HAGG) when sera was omitted from the culture media. With 20% human serum present in the media, HAGG induced a dose-related inhibition of PMNC adhesions with concentrations as low as 10 micrograms/ml producing a significant effect. This inhibitory action of HAGG, which was optimally expressed after 30 min of incubation, seemed to be directed at the PMNC rather than the endothelium. Heat-inactivation of the sera resulted in a marked decline of the inhibitory activity of HAGG. Aggregates of size 15-21 s were demonstrated to be most effective in inhibiting PMNC attachment and it is complexes of this size which are commonly found in the circulation of patients with chronic inflammatory diseases. Immune complex modification of PMNC adherence may control leucocyte extravasation during inflammation.

The prevalence and management of pain in patients with AIDS: a review of 134 cases

In light of the lack of any prior systematic evaluations of the prevalence and types of pain syndromes and treatments found in patients with AIDS, a chart review study was undertaken to evaluate this issue. Fifty-two of 96 charts reviewed (54%) had at least one note on nonprocedural pain or analgesic prescription. Although chest pain was the most prevalent pain location (22%), presumably because of the high incidence of Pneumocystis carinii pneumonia, other possible AIDS-related entities, such as peripheral neuropathy and thrombophlebitis, were also found. No specific AIDS syndromes could be identified that were related to a higher incidence of pain. Nearly one-third of patients with pain received codeine (31%), others received acetaminophen (27%), and 17% of patients received acetaminophen and oxycodone HCl. Specific pain management interventions must be evaluated and applied to control the nontrivial occurrence of pain in patients who have AIDS symptoms that may be overlooked by the physician given the overwhelming disease process.

Lens opacities classification system II (LOCS II)

The Lens Opacities Classification System, version II (LOCS II), uses a set of colored slit-lamp and retroillumination transparencies to grade different degrees of nuclear, cortical, and subcapsular cataract. The system uses four nuclear standards for grading nuclear opalescence and color, five cortical standards, and four subcapsular standards. The LOCS II can be used to grade patients' cataracts at the slit lamp or to grade slit-lamp and retroillumination photographs; it is easy to learn and can be applied consistently by different observers. We obtained very good interobserver reproducibility of the clinical gradings at the slit lamp, excellent intraobserver reproducibility, very good to excellent interobserver reproducibility of photographic gradings, and good agreement between clinical and photographic gradings. The LOCS II is potentially useful for both cross-sectional and longitudinal studies of cataract.

Identification of Escherichia coli DNA helicase IV with the use of a DNA helicase activity gel

A DNA helicase activity gel was developed based on the assumption that DNA helicases could unwind double-stranded DNA in a polyacrylamide matrix. The production of single-stranded DNA was detected by staining the activity gel with acridine orange and visualizing the gel under long-wave UV light. The products of DNA helicase activities appeared as red bands within a green fluorescent background. A novel DNA helicase, called helicase IV, was detected in crude extracts of Escherichia coli with the use of the helicases activity gel assay. The new DNA helicase was purified to near homogeneity. The chromatographic properties and the sequence of its 11 amino-terminal residues proved that helicase IV was distinct from all of the previously described DNA helicases from E. coli.

Cloning of the rec-2 locus of Haemophilus influenzae

A collection of transposon mutants of Haemophilus influenzae was constructed by additive transformation with mutagenized chromosomal DNA. A rec-2::miniTn10 km mutation was cloned from a transformation-defective member of the mutant collection, followed by the reconstruction of the wild-type rec-2 locus by recombination to create pDM62. Southern blots showed that the commonly studied Rec-2 mutant, Rd(DB117)rec-, contained either a large deletion or a substitution that removed part of rec-2 locus. A collection of transposon mutations in pDM62 was used to characterize the rec-2 locus by complementation. A corresponding collection of mutants was also constructed. A single segment was required to complement the transformation defect in Rd(DB117)rec-. All of the transformation-defective transposon mutants failed to translocate donor DNA into then cell, in agreement with previous studies of Rd(DB117)rec-.

Binding of monomeric and aggregated immunoglobulin to enzymes. A source of artefact in antibody assays

Pepsinogen has previously been shown to bind non-specifically to immune complexes and aggregated immunoglobulins. We demonstrate here using a solid-phase immunoassay that immunoglobulins aggregated by heat or glutaraldehyde bind non-specifically to several different enzymes. Some of these, including pepsinogen (marketed as pepsin), hyaluronidase and trypsin, are used in the breakdown of tissues or biochemical preparations during the preparation of antigens. Contamination of impure antigens by enzyme is likely to lead to products which bind non-specifically to immune complexes. This can cause misidentification of complexes as antibodies. We recommend that all tests for specific antibody involving the use of antigens prepared by these or other enzymes should include a control with aggregated immunoglobulin substituted for the test serum.

Reduction of the surface charge of blood polymorphonuclear cells by rheumatoid sera and heat induced aggregated human IgG (HAGG)

Cell electrophoresis identifies two main subpopulations of blood polymorphonuclear cells (PMNs), which in terms of the speed of their anodic migration are referred to as the fast and slow population. When blood PMNs from normal healthy subjects were incubated in medium containing 20% RA serum there was a decrease in the percentage of fast cells with a corresponding increase in the slow population that was directly related to the levels of circulating immune complexes present in the sera. Similar results were obtained when using heat induced aggregated human IgG (HAGG) or Candida albicans instead of RA serum. The 'slowing' effect of HAGG, which was transient and time dependent, appeared to be due to its internalisation by the PMNs. These results suggest that in RA the large number of blood PMNs with a low surface charge (i.e., the slow population) may arise as a result of the constant interaction of these cells with circulating immune complexes.

Lens Opacities Classification System

The Lens Opacities Classification System (LOCS) is a simple system for classifying age-related human lens opacities at the slit lamp or in retroilluminated and slit-lamp photographs. The system employs a set of standard Neitz CTR retroilluminated black-and-white photographs for classification of cortical and posterior subcapsular cataracts and a single color slit-lamp photograph for classification of nuclear color and opalescence. We present a detailed description of the system.

Evaluation of a Lens Opacities Classification System

A simple system, based on standard photographs, has been developed to classify lens opacities. The system allows the definition of cataract cases and noncases according to the location of lens opacification (nuclear, cortical, posterior subcapsular) and its extent (early or more advanced). Evaluation of the system has shown good to excellent reproducibility for clinical and photographic classifications. Comparisons of clinical and photograph-derived gradings has shown generally good agreement in classifying the presence and type of cataract; this agreement is highest for nuclear cataract. Photographic gradings of posterior subcapsular and, to a lesser degree, cortical opacities tend to underestimate the extent of opacification found by clinical gradings. The Lens Opacities Case-Control Study system is simple, reproducible, and easy to implement; it is offered for use in case-control and other cross-sectional studies of cataract with compatible classification goals.

Genetic transformation system in the archaebacterium Methanobacterium thermoautotrophicum Marburg

A wild-type strain of Methanobacterium thermoautotrophicum Marburg was transformed by DNA from strains resistant to 5-fluorouracil. Recipient cells were grown without selection on gellan gum (GELRITE) plates with DNA. Drug-resistant cells were recovered by replica plating the resulting colonies onto drug plates. Transformation required high-molecular-weight DNA with appropriate markers and was not observed on agar or in liquid media under a variety of conditions.

Sources of variance in the objective documentation of human cataractous change with Topcon SL-45 and Neitz-CTR retroillumination photography and computerized image analysis

In the application of Topcon SL-45 Scheimpflug slit and Neitz CTR retroillumination photography to in vivo documentation of cataractous change, several sources of variance affect the results of each technique. We have measured the between-person, between-photographer, between-focal plane (Neitz), between-photo session, replicate photograph (Topcon), between-image analyst and replicate image analysis variances encountered in in vivo documentation of human cataracts with the Topcon SL-45 and Neitz-CTR cameras and our system of computerized image analysis.

Effect of age and chronic obstructive pulmonary disease on the Breathalyzer estimation of blood alcohol level

Twenty volunteers, 10 with chronic obstructive pulmonary disease (COPD) and 10 with no disease, ingested a vodka cocktail. Serial determinations of blood alcohol level (BAL) by gas-liquid chromatography and simultaneous Breathalyzer estimations of BAL were used to calculate blood:breath alcohol partition coefficients (PCs). Data from the present study were combined with data obtained in a previous study using identical methodology to examine the relationship between age and BAL estimation. It was found that the Breathalyzer significantly underestimated BAL as a function of age. It was hypothesized that the underestimation may be due to closing volume (CV) as the Breathalyzer samples end-expiratory breath.

The mechanism of action of capsaicin on sensory C-type neurons and their axons in vitro

The selective excitant and neurotoxic action of capsaicin on vagal sensory neurons in the rat has been investigated in vitro using three techniques: extracellular recording of compound spike potentials from the whole nerve; intracellular recording from ganglion cells using single-electrode current and voltage clamp; and electron microscopy of the nerve and nodose ganglion. Capsaicin (0.1-10 microM) depolarized vagal sensory C fibres and cell bodies, and produced an increased conductance. The conductance increase appeared to be due to an increased permeability to sodium and calcium, plus a secondary increase in potassium (and perhaps chloride) conductance consequent upon calcium entry. The early entry of calcium seems to be a significant priming event in the neurotoxic process, since dramatic ultrastructural changes take place within a few minutes of capsaicin application, which are minimized by removing extracellular calcium ions. The observations indicate that in sensory C neurons capsaicin opens a conductance of limited specificity and that a resultant large calcium entry is closely involved in the rapid development of cell injury.

MRL-lpr/lpr mice show an impairment of IgG aggregate removal which relates to parameters of disease activity

MRL-lpr/lpr mice show an age-related impairment in the removal of heat-aggregated IgG (HAGG) from the circulation. The female mice, which have an earlier mortality than their male counterparts, clear HAGG more slowly than the male animals. Delay in clearance of this probe of mononuclear phagocytic system (MPS) function relates directly to high levels of circulating immune complexes (CIC) and to significant renal damage. In addition it relates indirectly to hepatic and splenic uptake of HAGG. MPS saturation plays a significant role in the pathogenesis of the disease seen in MRL-lpr/lpr mice.

The interaction of stimulus and reinforcer control in complex temporal discrimination

Six pigeons were trained in a discrete-trials signal-detection procedure to discriminate between a fixed-duration stimulus (5 s or 20 s) and a set of variable durations ranging from 2.5 s to 57.5 s in steps of 5 s. For each fixed-duration stimulus, the ratio of reinforcer frequencies contingent upon reporting the fixed versus the variable stimulus was systematically manipulated. Detection performance was well controlled by both the stimulus value and the reinforcer ratio. Both the discriminability between the fixed duration and the set of variable durations, and the discriminability between the fixed duration and each of the variable durations, were independent of the reinforcer-frequency ratio when discriminability was measured as log d. The sensitivity of response bias to reinforcement-ratio changes was independent of the value of the fixed duration, but was not independent of the discriminability of the variable durations from the fixed durations. Under current models, discriminability measures in complex temporal discrimination may be independent of biasing manipulations, but bias measures are not independent of stimulus values.

Isolation of Haemophilus influenzae genes that suppress Escherichia coli polA mutations

Haemophilus influenzae was found to produce a DNA polymerase that was similar to polymerase I of Escherichia coli. E. coli polA mutants were used as backgrounds for the selection of H. influenzae polA suppressor genes. Six different H. influenzae fragments were isolated that could suppress E. coli polA mutations. None of the suppressors appeared to encode the H. influenzae equivalent of the E. coli polA gene. One type of clone, represented by pGW41, caused a polymerase I activity to appear in a suppressed polA1 mutant. Plasmids from the pGW41 class contained two genes (pol-2 and pol-3) that were both required for polA suppression. Mutated nonsuppressing derivatives of the pGW41 class were used to create H. influenzae mutants that were deficient in polymerase I.

Rheumatoid blood decreases the adherence of polymorphonuclear cells (PMNs) to cultured endothelium

Rheumatoid sera and plasma inhibited the adherence of normal blood polymorphonuclear cells (PMNs) to cultured porcine endothelium. This inhibition of adhesion was not seen when PMNs were treated with the plasma or serum from normal subjects or patients with other inflammatory arthropathies. The abrogation of PMN adherence was directly related to the levels of circulating immune complexes and was not dependent upon the type of anti-inflammatory therapy that the patients were receiving nor on any of the recorded clinical parameters. A similar inhibition of adhesion was seen with heat induced aggregated human IgG (HAGG) provided that serum was present in the culture medium. In view of these results we propose that circulating immune complexes in RA may have a significant role in controlling the interaction of PMNs with vascular endothelium and in perpetuating the entry of these cells into the synovial fluid of the inflamed joints.

Electron microscopy of single-stranded structures in the DNA of competent Haemophilus influenzae cells

Chromosomal DNAs from exponential-phase and competent cells of Haemophilus influenzae were examined by electron microscopy to determine whether the chromosome undergoes structural changes during competence development. Single-stranded gaps and single-stranded tails formed in chromosomal DNA during competence development. The generation of gaps was dependent on the rec-2 function. Since the rec-2 mutant is defective in the translocation of donor DNA, it was inferred that the gaps were involved in the translocation step of transformation. The generation of single-stranded tails was independent of the rec-1 and rec-2 genes. Therefore, these structures were assumed to play no direct role in the interaction of donor and recipient DNAs during transformation. Gaps were preferentially associated with a readily denaturable, possibly A + T-rich fraction of the genome. This finding raised the possibility that hot spots for transformation might be associated with A + T-rich DNA.

Is the surface charge on granulocytes really decreased following their exposure to chemotactic factors?

The mean axial ratio of polarised granulocytes has been determined and interpolated with plots relating settling factors (the inverse of relative frictional coefficients) to the axial ratios of simple isotropic solids. The estimate for the relative frictional coefficient of polarised granulocytes obtained by this procedure (f/fo = 1.11) suggests that a change in cell shape can account largely for the previously observed decreases in granulocyte electrophoretic mobility that occur following exposure to chemotaxins. In consequence, the widely held view that chemotaxins induce an alteration in cell surface charge is open to re-appraisal.

rpe, a cis-acting element from the strA region of the Haemophilus influenzae chromosome that makes plasmid establishment independent of recombination

Plasmids that share homology with the Haemophilus influenzae chromosome transform wild-type cells more efficiently than they transform recombination-defective mutants. A 5.2-kilobase-pair chromosomal fragment containing the strA gene of H. influenzae was found to promote efficient plasmid establishment in recombination-defective mutants. A cis-acting element in the insert, called rpe for rec-less plasmid establishment, promoted plasmid transformation in rec-1 and rec-2 mutants without suppressing the recombination defects of these strains. The rpe locus increased plasmid transformation in wild-type cells without interfering with the pathway of plasmid establishment that is dependent on recombination functions.

Pepsinogen--an immunoglobulin binding artefact in 'collagen' preparations

It has previously been shown that extracts of human articular cartilage, many many of which contain type II collagen, react with heat-aggregated immunoglobulin and artificially prepared immune complexes. Sera from patients with rheumatoid arthritis and psoriatic arthritis, but not from patients with inflammatory bowel disease, react with these extracts. There are two distinct patterns of binding, either as low molecular weight immune complexes or as free antibody directed against collagen. Aggregate-binding activity identified in extracts of human articular cartilage following pepsin digestion was found to be distinct from collagen in its salt solubility. Further purification of this aggregate-binding factor by SDS gel electrophoresis has shown it to be an artefact resulting from the binding of small immune complexes to pepsinogen present in the pepsin preparation used to digest the cartilage.

Cellular processing of bovine factors X and Xa by cultured bovine aortic endothelial cells

Previous studies have shown that Factor X and Factor Xa bind specifically to distinct sites on the endothelial cell surface. Since the coagulant activity of a cell-bound clotting protein is dependent on its remaining on the cell surface, endocytosis and degradation studies have been carried out. Cell-bound Factor X was internalized at 0.07 fmol/min/10(6) cells, a rate slower than its dissociation from the cell surface. Endocytosed Factor X was not degraded, but was returned to the cell surface. In contrast, Factor Xa was internalized at an initial rate of 0.38 fmol/min/10(6) cells and subsequently degraded at about the same rate. The degradation of Factor Xa was prevented by chloroquine. These results suggest that Factor Xa is internalized and degraded by a lysosomal-dependent pathway. Studies with Factor X- and Xa-colloidal gold conjugates showed endocytosis proceeding at coated pit regions, and accumulation of Factor Xa-gold particles in lysosome-like structures. Endocytosis was studied as a clearance pathway for cell-bound Factor Xa by activating Factor X with Factors IXa and VIII on the endothelial cell surface. Endocytosis of the Factor Xa formed was significant, as only 44% of the Factor Xa formed was released into the supernatant, whereas the remainder was internalized and degraded. Thus, endocytosis of Factor Xa bound to its specific endothelial cell sites may be an important factor in the balance of vessel wall hemostatic mechanisms.

MRL mice show an age-related impairment of IgG aggregate removal from the circulation

The fate of heat-aggregated human IgG (HAGG) was examined in young and old autoimmune MRL-lpr/lpr and MRL-+/+ mice and compared to BALB/c mice of different ages. Following iv injection of [125I] HAGG the older MRL-lpr/lpr and MRL-+/+ mice showed impaired hepatic and splenic uptake of this material. In addition the clearance rate of HAGG was significantly slower in the older MRL-lpr/lpr mice (t1/2 = 50 min) when compared to younger controls (t1/2 = 13 min) although this age-related retardation of clearance was not observed in the MRL-+/+ mice. No difference was seen in the clearance rate or organ uptake studies of the two age groups of BALB/c mice. Catabolic studies using trichloracetic acid suggested that the HAGG was catabolized to smaller fragments with time but not to such a great extent in the older diseased animals, again no age-related difference was seen in the BALB/c mice. Our studies suggest that with age both autoimmune strains of MRL mice show some saturation of the mononuclear phagocytic system (MPS) and that this process is more obvious in the MRL-lpr/lpr mice. MPS saturation may play a role in the pathogenesis of autoimmune disease in these mice.

Measurements of maximum respiratory pressures in polymyositis and dermatomyositis

Measurements of maximum respiratory pressures and routine pulmonary function tests were performed in 8 patients with polymyositis (PM) and 2 patients with dermatomyositis (DM). Serial measurements of routine pulmonary function tests in 8 patients remained unchanged. Maximum respiratory pressures were decreased initially in 7 patients with proximal muscle weakness and clinically active muscle disease and improved with corticosteroid therapy in the 5 patients who were followed serially. In 3 patients with clinically stable disease the maximum respiratory muscle power was normal. Serial measurements of maximum respiratory pressures have been of value in monitoring patients with PM and DM.

Studies on the significance of the R1 anti-reticulin antibody associated with gluten sensitivity

The R1 type anti-reticulin antibody (ARA) is closely associated with gluten-sensitive enteropathy. It disappears from the circulation within a few weeks of starting on a gluten-free diet and often reappears following gluten challenge. It is not clear how gluten ingestion leads to the production of the ARA. We have investigated four possibilities. (1) The ARA is simply a food antibody generated against meats in the diet. (2) The ARA is an anti-gluten antibody which cross-reacts with reticulin. (3) Gluten binds to gut reticulin in vivo rendering reticulin autoimmunogenic. (4) Immune complexes of gluten and anti-gluten antibody bind to reticulin (by virtue of the affinity that gluten has for reticulin) to give the appearance of an ARA in immunofluorescence tests. Our results do not support any of these possible explanations, and the significance of the ARA remains obscure.

Monocytic differentiation induced by 1,25 dihydroxyvitamin D3 in myeloid cells: an ultrastructural immunocytochemical study

We have studied, by ultrastructural morphology and immunocytochemistry, the alterations that occur in cells from the HL60 leukaemia cell line and from patients with CGL following incubation in vitro with 1,25(OH)2D3 for 2-5 days. The main morphological changes observed were in the nuclear shape, the development of autophagic vacuoles and the appearance of a population of small granules in the cytoplasm. These changes were associated with a significant reduction in MPO activity and increased expression of membrane antigens detected by the monocyte-specific McAb FMC17 and FMC32, as shown by the IGM at EM level, and a decrease in granulocyte-specific antigens demonstrated by the McAb FMC10. These observations suggest that promyelocytes and myelocytes could transform into monocyte-like cells and that this remodelling of cells was associated with autophagic digestion of cellular structures.

The effect of vitamin D3 metabolites on normal and leukemic bone marrow cells in vitro

We studied the effects of 1,25-dihydroxyvitamin D3 and other metabolites of vitamin D3 on the maturation in liquid culture and on colony formation in semisolid media of marrow and buffy coat cells from patients with myeloid leukemias and from normal individuals. After incubation with 1,25-dihydroxy-vitamin D3, a proportion of both normal and leukemic myeloid cells resembled cells of the monocyte-macrophage lineage; these cells expressed alpha-naphthylacetate esterase and were able to phagocytize and kill candida organisms. When granulocyte-macrophage progenitor cells (CFU-GM) were incubated with 1,25-dihydroxyvitamin D3, the number of monocyte-macrophage colonies was increased and the number of granulocyte colonies was reduced; megakaryocyte colony formation (CFU-Mk) was inhibited substantially; and there was no effect on erythroid (BFU-E) or multilineage (CFU-GEMM) progenitor cell colony formation. We propose that 1,25-dihydroxyvitamin D3 may induce cells that are normally committed to differentiate along the granulocytic pathways to differentiate instead along the monocyte-macrophage pathway. If these in vitro observations reflect the in vivo activity of 1,25-dihydroxyvitamin D3, it may be involved in the modulation of collagen deposits in the bone marrow.

Isobias and alloiobias functions in animal psycophysics

An analogue of the human yes-no detection task was used to train six pigeons to discriminate luminance differences under two different reinforcer-scheduling procedures. When a controlled reinforce-ratio procedure was used, relative stimulus frequency was constant at .5, and relative reinforcer frequency for correct detections was held constant at three different values for each of five luminance differences. When an uncontrolled reinforcer-ratio procedure (the typical detection paradigm) was used, relative reinforcer frequency for correct detections was allowed to covary with changes in relative stimulus frequency for each of five luminance differences. Two measures of bias, response bias (Davison & Tustin, 1978) and the detection-theory likelihood-ratio measure (beta obt), were compared. The controlled reinforcer-ratio procedure generated equal- or iso-response-bias functions, and the uncontrolled reinforcer-ratio procedure gave changing or alloio-response-bias functions. The Davison-Tustin model accounted for 88% and 93% of the data variance in the controlled and uncontrolled reinforcer-ratio procedures, respectively. The best-fitting equal-beta functions accounted for an average of 53% and 69%, respectively, in the two procedures. In addition, neither procedure gave constant measures of beta obt for constant bias manipulations across different discriminability measures.

Delayed signal detection, differential reinforcement, and short-term memory in the pigeon

In two discrete-trial delayed-detection experiments, six pigeons were trained on dependent concurrent variable-interval schedules. Pecking a red side key was reinforced when the brighter of two white lights (S1) had been presented on the center key, and pecking a green side key was reinforced when the duller of two white lights (S2) had been presented on the center key. Incorrect responses were red side-key pecks following S2 presentations and green side-key pecks following S1 presentations; these resulted in three-second blackouts. In Experiment 1, the time between presentation of S1 or S2 on the center key and the onset of the red and green side keys was varied nonsystematically from 0.06 seconds to 19.69 seconds across experimental conditions. Stimulus discriminability decreased as the stimulus-choice delay increased. A rectangular-hyperbolic function better described this decrease in discriminability over time than did a negative-exponential function. In Experiment 2, at each of three stimulus-choice delays (0.06, 3.85, and 10.36 seconds), relative reinforcer frequency for correct responses to the red and green side keys was varied by changing the values of the dependent concurrent variable-interval schedules. The sensitivity of choice to relative reinforcer frequency was independent of the decrease in stimulus discriminability with increasing stimulus-choice delay.