The assessment of pain in rheumatoid arthritis: disease differentiation and temporal stability of a behavioral observation method

An observation method for the assessment of pain behaviors in patients with rheumatoid arthritis (RA) has been developed. We investigated the extent to which the frequencies of pain behaviors differentiated patients with RA and patients with chronic low back pain from depressed and nondepressed, pain free, control subjects. The reliability of the pain behavior frequencies of patients with RA across 2 observation sessions also was determined. Total pain behavior scores clearly differentiated patients with RA and low back pain from depressed and nondepressed, pain free, control subjects. Pain behavior observed in patients with RA showed a high degree of stability over time. The results of our study suggest that the behavioral observation method will prove useful in the assessment of RA pain in clinical and research settings.     

Lymphocyte proliferation assays as potential biomarkers for toxicant exposures

Recently there has been interest in developing assays that can be used as indicators (biomarkers) of exposure to toxic agents. We have been exploring the potential utility of three lymphocyte proliferation assays [the responses of B lymphocytes to the mitogen lipopolysaccharide (LPS), the responses of T lymphocytes to the mitogen concanavalin A (ConA), and the responses of T lymphocytes to antigenic stimuli in a mixed lymphocyte culture (MLC) assay] as biomarkers of toxicant exposure. Studies were initiated to assess the applicability and specificity of these assays and to investigate the mechanisms by which toxicants alter lymphocyte proliferation. All studies were performed using cells isolated from Fischer 344 rats. To assess applicability, mitogen assays were performed using in vitro exposures to eight different toxicants: hydroquinone, benzoquinone, Aroclor 1254, styrene oxide, and the salts of mercury, cadmium, chromate, and nickel. In vitro concentrations spanned five orders of magnitude (100 to 0.01 mg/l). At the lowest concentration tested, all eight compounds induced changes in at least one mitogen assay, indicating that these assays may be applicable to a wide range of toxicants. Variations of the ConA and MLC assays were used to test for specificity. In both assays, splenocytes taken from rats exposed in vivo to either chromate or to cadmium responded differently when the cells were cocultured with exogenously added chromate or cadmium ions, indicating that it may be possible to detect exposure to a specific toxicant by performing modified lymphocyte proliferation assays. In the mechanistic studies, splenocytes from cadmium and chromate-treated rats altered the ConA-induced proliferation of cocultured syngeneic cells. In addition, the antigenicity of splenocytes isolated from cadmium-treated rats was enhanced when these cells were used as stimulators for allogeneic splenocytes. The results of these studies indicate that lymphocyte proliferation assays may be useful for detecting exposure to a wide range of toxicants and that variations of these assays may be useful for implementing immunologically based tests for detecting exposures to specific chemicals.     

Angiotensin converting enzyme immunohistochemistry in rat brain and pituitary gland: correlation of isozyme type with cellular localization

We have localized angiotensin converting enzyme in rat brain and pituitary gland immunohistochemically with an anti-rat lung angiotensin converting enzyme monoclonal antibody. The distribution of immunoreactive angiotensin converting enzyme is identical with that of binding sites for the angiotensin converting enzyme inhibitor, [3H]captopril. Most intense staining is in the choroid plexus and subfornical organ, with intermediate values in the caudate-putamen, globus pallidus, entopeduncular nucleus, pars reticulata of the substantia nigra, posterior pituitary and anterior pituitary. Lower levels are observed in the supraoptic and paraventricular nuclei of the hypothalamus. Within the basal ganglia angiotensin converting enzyme immunoreactivity is distributed throughout the neuropil; no cell bodies are stained, even after colchicine treatment. The punctate pattern of immunoreactivity in the anterior pituitary corresponds to the distribution of endothelial cells. The posterior pituitary is stained diffusely. Angiotensin converting enzyme is increased by 45% in the posterior lobe after pituitary stalk section, demonstrating that this diffuse staining is associated with pituicytes. Antibody specificity was demonstrated by the immunoaffinity purification of angiotensin converting enzyme to homogeneity from crude tissue extracts using anti-angiotensin converting enzyme antibody and protein A-sepharose. The apparent molecular weight by sodium dodecyl sulfate polyacrylamide gel electrophoresis of lung, choroid plexus and anterior pituitary angiotensin converting enzyme is 175,000. In the substantia nigra and caudate putamen, where angiotensin converting enzyme is localized to neuronal as opposed to epithelial cells, the molecular weight is 165,000. The pituicyte angiotensin converting enzyme of the posterior pituitary is 170,000 daltons.     

Terminal acute myelogenous leukemia in a patient with congenital agranulocytosis

Congenital agranulocytosis terminating in acute myelogenous leukemia has been previously reported in only two cases of adolescent males. We describe the clinical and laboratory features of a 13-year-old male with congenital agranulocytosis, treated with G-CSF with initial good neutrophil response, who subsequently developed acute myeloid leukemia. This rare complication may define a preleukemic subset of patients for whom G-CSF therapy is ineffective. The diagnostic challenges of this case are presented.     

Normalization of the blood lactate profile in athletes

The power output-blood lactate or velocity-blood lactate relationship, the lactate "profile", is a widely used method for the evaluation of athletes. Recent observations have suggested a shift in the blood lactate profile when athletes are fatigued, as at training camps. This study was designed to determine whether the blood lactate profile could be corrected for progressive muscle glycogen depletion by normalizing for the peak exercise blood lactate concentration. Ten well-trained subjects performed incremental cycle ergometer exercise followed by supramaximal exercise (Wingate test) following 3 days of usual and 3 days of heavier than usual training. Following heavier than usual training, blood lactate accumulation was reduced during submaximal exercise such that the power output associated with a lactate concentration of 4 mM was significantly increased (3.08 vs 3.51 W/kg). The maximal blood lactate concentration was also reduced (14.8 vs 12.7 mM) although average supramaximal power output was unchanged (9.03 vs 8.92 W/kg). When the submaximal blood lactate concentrations were normalized for the maximal blood lactate concentration, there were no significant differences in the power output associated with 20% (2.6 vs 2.7 W/kg), 25% (3.1 vs 3.2 W/kg), or 30% (3.3 vs 3.5 W/kg) of maximal lactate. The results suggest that normalization based on peak exercise blood lactate may be a useful strategy for circumventing one of the primary practical barriers to the use of the blood lactate profile in athletes.     

"Crack smoke" is a respirable aerosol of cocaine base

The smoking of cocaine base [corrected] ("crack") has emerged as a significant substance abuse problem. A detailed characterization of cocaine smoke is a prerequisite for studies of its pharmacokinetics, abuse potential and toxicity. Model pipes were used to generate cocaine smoke analogous to that inhaled by human "crack" abusers. Using procedures to minimize pyrolysis, cocaine base smoke was determined to be 93.5% cocaine particles with the remainder being cocaine vapor. The average particle size generated from all model pipes was 2.3 mu which is small enough to ensure deposition into the alveolar region of the human lung. Although this particle size is eminently respirable [corrected] by primates, a much smaller fraction will reach the alveolar region of rodents. Special generating procedures would therefore be required to expose rodents to meaningful doses of airborne cocaine that mimic the rapid absorption achieved by "crack" smokers.     

Effect of lipopolysaccharide and lipid A on mouse liver pyruvate kinase activity.

Several investigators have reported lipid A as the biologically active unit in the lipopolysaccharide (LPS) molecule. To determine if lipid A was responsible for the reported increases in pyruvate kinase, mice were injected with endotoxin from Salmonella typhimurium SR-11, the Re mutant of Salmonella minnesota R 595, and lipid A-bovine serum albumin conjugate. The livers were homogenized and the activity of pyruvate kinase was measured. Similar increases in enzyme were obtained with all three preparations. These data imply that the lipid portion of the LPS molecule was responsible for alterations in host enzyme activity. To further determine if the lipid portion was the active unit, a lipid-degraded endotoxin (endotoxoid) prepared by potassium methylate treatment was inoculated into mice. An initial increase in liver pyruvate kinase activity was observed with all preparations. The marked increase observed at 16 h with the native product and lipid A conjugate was not obtained with the endotoxoid. These experiments extend and confirm previous observations that lipid A is responsible for the effects associated with LPS. Animals tolerant to endotoxin from S. typhimurium SR-11 were challenged with endotoxin from the Re mutant. A significant increase in pyruvate kinase activity was not obtained, suggesting that anti-O antibodies are not important in the development of tolerance.     

Effects of estrogen replacement on the progression of coronary-artery atherosclerosis

BACKGROUND: Heart disease is a major cause of illness and death in women. To understand better the role of estrogen in the treatment and prevention of heart disease, more information is needed about its effects on coronary atherosclerosis and the extent to which concomitant progestin therapy may modify these effects. METHODS: We randomly assigned a total of 309 women with angiographically verified coronary disease to receive 0.625 mg of conjugated estrogen per day, 0.625 mg of conjugated estrogen plus 2.5 mg of medroxyprogesterone acetate per day, or placebo. The women were followed for a mean (+/-SD) of 3.2+/-0.6 years. Base-line and follow-up coronary angiograms were analyzed by quantitative coronary angiography. RESULTS: Estrogen and estrogen plus medroxyprogesterone acetate produced significant reductions in low-density lipoprotein cholesterol levels (9.4 percent and 16.5 percent, respectively) and significant increases in high-density lipoprotein cholesterol levels (18.8 percent and 14.2 percent, respectively); however, neither treatment altered the progression of coronary atherosclerosis. After adjustment for measurements at base line, the mean (+/-SE) minimal coronary-artery diameters at follow-up were 1.87+/-0.02 mm, 1.84+/-0.02 mm, and 1.87+/-0.02 mm in women assigned to estrogen, estrogen plus medroxyprogesterone acetate, and placebo, respectively. The differences between the values for the two active-treatment groups and the value for the placebo group were not significant. Analyses of several secondary angiographic outcomes and subgroups of women produced similar results. The rates of clinical cardiovascular events were also similar among the treatment groups. CONCLUSIONS: Neither estrogen alone nor estrogen plus medroxyprogesterone acetate affected the progression of coronary atherosclerosis in women with established disease. These results suggest that such women should not use estrogen replacement with an expectation of cardiovascular benefit.     

Identification of two point mutations and a one base deletion in exon 19 of the dystrophin gene by heteroduplex formation

Two thirds of the Duchenne muscular dystrophy population haveeither gene deletions or duplications. The nondeletion/duplicationcases are most likely the result of point mutations or smalldeletions and duplications that cannot be easily identifiedby current strategies. The major obstacle in identifying smallmutations is due to the large size of the dystrophin gene. Weselectively screened 5 DMD exons containing CpG dinucleotidesin 110 DMD patients without detectable deletions or duplications.Nonsenses mutations are frequently due to a C- to -T transitionwithin a CG dinucleotide pair. To screen for the nonsense mutations,we used the heteroduplex method. Utilizing this approach, weidentified 2 different nonsense mutations and a single basedeletion all occurring in exon 19. This is the first reportof a clustering of small mutations in the the dystrophin gene.