Impaired production and lack of secretion of interleukin 1 by human breast milk macrophages

Interleukin 1 (IL-1) production by human breast milk macrophages (HMMø) in response to bacterial lipopolysaccharides (LPS) was investigated in 49 healthy mothers and compared with that of blood monocytes (HMo). IL-1 activity in 24 h HMMø culture supernatants was in most cases below the assay detection limits and much smaller than that of stimulated HMo (72 +/- 17 u/ml). Intracellular IL-1 activity in response to LPS in HMMø raised from less than 2 +/- 1 u/ml to 19 +/- 12 u/ml and was similar to that found in stimulated HMo (16 +/- 4 u/ml). Neither the low IL-1 production by HMMø nor its release into supernatants could be increased by stimulating with higher LPS concentrations (40-400 micrograms/ml) or when longer culture times were assayed (24-72 h). Inhibiting the production of prostaglandins by adding indomethacin to HMMø cultures, caused no effect either on IL-1 production or on its secretion to supernatants. The presence of inhibitors for the IL-1 thymocyte proliferative assay, in supernatants from HMMø, was excluded by mixing experiments with a known amount of IL-1. Thus, we conclude that HMMø produce four or five times less IL-1 than HMo in response to LPS stimulus. Furthermore, HMMø are completely unable to release the IL-1 produced.

Tumor necrosis factor expression in human epithelial tumor cell lines

Tumor necrosis factor (TNF) is a monokine with in vitro cytotoxicity for some but not all tumor cells. The basis for sensitivity and resistance to the antitumor effects of this agent remains unclear. The present studies have monitored the effects of TNF on 14 epithelial tumor cell lines. Eleven of these cell lines were resistant to the growth inhibitory effects of TNF (50% inhibitory concentration greater than 1,000 U/ml). 12 of the 14 tumor cell lines has detectable levels of high affinity cell surface TNF binding sites, thus suggesting that resistance was not often due to the absence of cell surface TNF receptors. Northern blot analysis demonstrated that three of the eleven resistant cell lines expressed detectable levels of TNF mRNA. Furthermore, both sensitive and resistant epithelial tumor cells had the capacity to express TNF transcripts in the presence of the protein synthesis inhibitor, cycloheximide. Finally, the presence of TNF expression at the RNA level is shown to be associated with the production of a TNF-like protein in the resistant Ov-D ovarian carcinoma cells. These findings suggest that certain human epithelial tumor cell lines inherently resistant to TNF also express this cytokine.

Induction of tumor necrosis factor expression and resistance in a human breast tumor cell line

Tumor necrosis factor (TNF) is a polypeptide cytokine that is cytotoxic to some but not all tumor cells. The basis for resistance to the cytotoxic effects of this agent remains unclear. We have studied the development of TNF resistance in human ZR-75-1 breast carcinoma cells. ZR-75-1 cells have undetectable levels of TNF RNA and protein. However, TNF transcripts are transiently induced in these cells by exposure to recombinant human TNF. This induction of TNF RNA is associated with production of TNF-like protein in cell lysates and culture supernatants. Stable resistance to TNF-induced cytotoxicity develops when ZR-75-1 cells are exposed to increased concentrations of TNF. The TNF-resistant cells, designated ZR-75-1R, continuously express TNF transcripts and a TNF-like protein. Furthermore, ZR-75-1R cell supernatants contain cytotoxic activity that is abrogated by polyclonal antibody against TNF. The ZR-75-1R cells also possess TNF receptors that are occupied or down-regulated by the TNF-like protein. These findings thus suggest that (i) TNF induces TNF transcripts and production of a TNF-like protein in ZR-75-1 cells and (ii) resistance to TNF-induced cytotoxicity is associated with stable TNF expression.

Miliary tuberculosis and adult respiratory distress syndrome

Although, miliary tuberculosis is an unusual cause of severe acute respiratory failure, we describe nine patients with miliary tuberculosis who developed adult respiratory distress syndrome. This complication occurred in seven patients despite treatment with antituberculous drugs. In two patients who developed the syndrome, miliary tuberculosis was diagnosed only at postmortem. The presence of pulmonary hypertension in all cases and disseminated intravascular coagulation in seven cases suggests a possible pathophysiologic relationship with severe pulmonary vascular damage. The high mortality rate (88.8%) was associated with nonpulmonary organ system failure. Miliary tuberculosis should be considered in patients with adult respiratory distress syndrome of unknown etiology, and simple diagnostic procedures such as sputum, bronchial brushing, and gastric examination should be followed by invasive diagnostic procedures to confirm this etiology. Since untreated miliary tuberculosis is usually fatal, early recognition of this disease is of great importance, and specific therapy may play a lifesaving role.

Effects of calcium channel blockers on gastric emptying and acid secretion of the rat in vivo

Experiments were designed to evaluate the effects of three calcium channel blockers (verapamil, diltiazem and cinnarizine) on gastric emptying and secretion in the rat. Pretreatment with the calcium blockers delayed gastric emptying of phenol red in a dose-dependent manner. Verapamil was the most effective of the agents tested. Verapamil and diltiazem inhibited gastric acid secretion in the pylorus-ligated rat without affecting pepsin output. Cinnarizine was ineffective in this model. When the perfused lumen of the anaesthetized rat was used, verapamil was found to inhibit responses to carbachol or histamine more than those to pentagastrin. Further, we found a greater sensitivity to verapamil for basal compared with vagal-stimulated (2-deoxy-D-glucose) acid secretion. Neither diltiazem nor cinnarizine modified gastric acid secretion in this experimental model. These findings are discussed in relation to the role of extracellular calcium in gastric motility and secretion, and the existence of a regional and functional selectivity for calcium blockers is proposed.

Bioenergetic and cardiovascular responses to exercise in residents at 2.850 m, with asymptomatic Chagas' disease

Cardiovascular and energetic responses at rest, during 30 min of exercise (mechanical output: 125 watts) and for a subsequent recovery period of 5 min were compared in two groups, each comprising 21 residents at an altitude of 2.850 m. One group was in the asymptomatic phase of Chagas' disease with positive serological tests for T. cruzi, whereas the other was without Chagas' disease (negative serological tests). The two groups were similar as regards age, weight-for-height, blood parameters, nutritional status and heart and lung functions, including heart rate and frontal plane QRS axis determinations. At rest, they differed in that maximal and minimal arterial blood pressures were slightly but significantly lower in the group with Chagas' positive serological tests than in the controls. During exercise and recovery, the only differences between them and the controls were that their minimal diastolic arterial blood pressure was significantly lower. In absolute values, the rises in arterial pressure due to exercise were exactly the same in the two groups. Maximal O2 uptake was identical in both groups, as was exercise steady state VO2. These findings indicate that the asymptomatic subjects with Chagas' disease had a normal work capacity and were not affected by high altitude.

Turbidimetry of rheumatoid factor in serum with a centrifugal analyzer

We describe the simple, rapid turbidimetry of IgM rheumatoid factor in human serum by use of the Cobas-Bio centrifugal analyzer. Heat-aggregated human IgG is used as the antigen. The immunoturbidimetric reaction is monitored at 340 nm for 300 s, and the changes in absorbance after the antigen is added are used to prepare the standard curve. Test results are calculated from the stored curve and reported in int. units/mL, based on comparison with the WHO reference serum for rheumatoid factor. There is no interference from bilirubin (up to 340 mumol/L) or hemoglobin (up to 5600 mg/L). Serum samples with a triglyceride concentration greater than 2.20 mmol/L must be cleared of lipids before analysis. The standard curve is linear from 30 to 500 int. units/mL. Precision, accuracy, linearity, and sensitivity are quite acceptable. The CV was generally less than 5% for different concentrations of rheumatoid factor. Results agree well with those by a rate-nephelometric procedure on the Beckman ICS system (rs = 0.932). However, both correlate poorly with a modified classical Waaler-Rose test. Of 47 patients with rheumatoid arthritis, 34 had IgM rheumatoid factor in their serum, but the measured value did not reflect the activity of the disease.

Turbidimetry of rheumatoid factor in serum with a centrifugal analyzer

We describe the simple, rapid turbidimetry of IgM rheumatoid factor in human serum by use of the Cobas-Bio centrifugal analyzer. Heat-aggregated human IgG is used as the antigen. The immunoturbidimetric reaction is monitored at 340 nm for 300 s, and the changes in absorbance after the antigen is added are used to prepare the standard curve. Test results are calculated from the stored curve and reported in int. units/mL, based on comparison with the WHO reference serum for rheumatoid factor. There is no interference from bilirubin (up to 340 mumol/L) or hemoglobin (up to 5600 mg/L). Serum samples with a triglyceride concentration greater than 2.20 mmol/L must be cleared of lipids before analysis. The standard curve is linear from 30 to 500 int. units/mL. Precision, accuracy, linearity, and sensitivity are quite acceptable. The CV was generally less than 5% for different concentrations of rheumatoid factor. Results agree well with those by a rate-nephelometric procedure on the Beckman ICS system (rs = 0.932). However, both correlate poorly with a modified classical Waaler-Rose test. Of 47 patients with rheumatoid arthritis, 34 had IgM rheumatoid factor in their serum, but the measured value did not reflect the activity of the disease.

Measurement of urinary catecholamines and their catechol metabolites and precursor by liquid chromatography with column-switching and on-line fluorimetric and electrochemical detection

A new method is described for the determination of catecholamines and their precursor (3,4-dihydroxyphenylalanine), and separately of their catechol metabolites (3,4-dihydroxymandelic acid, 3,4-dihydroxyphenylacetic acid, 3,4-dihydroxyphenylethylene glycol and 3,4-dihydroxyphenylethanol) in urine. After a two-step pretreatment involving ethyl acetate extraction and adsorption onto alumina, the separation is performed by ion-pair reversed-phase high-performance liquid chromatography. A column-switching system enables complete separation of the most polar compounds without increase in the total analysis time. The column eluates are monitored with both fluorimetric and amperometric detectors, the relative responses of which are used as an index of peak purity. Reference values for twelve healthy adults are given.

Major surface protein of Toxoplasma gondii (p30) contains an immunodominant region with repetitive epitopes

Four monoclonal antibodies (mAb) against surface antigens of tachyzoites of Toxoplasma gondii were produced. Immunoprecipitation of extracts of 125I-labeled tachyzoites identified the same polypeptide with apparent molecular weight of 30 000 (p30). A competition binding assay indicated that a single region of p30 was recognized by all 4 of the mAb. Furthermore, we found that single mAb inhibited 25-50% of the specific binding of antibodies of patients with toxoplasmosis to the antigenic extract of tachyzoites. It appears, therefore, that p30 is the most immunogenic constituent of tachyzoites, and that a single region of this molecule contains most of the immunogenic activity. Finally, a two-site/one-antibody immunoradiometric assay with the same mAb indicated that the p30 molecule is multivalent with respect to the expression of a single epitope.

Toxoplasma gondii: redistribution of monoclonal antibodies on tachyzoites during host cell invasion

Immunodetection of protein P30, a major surface antigen of Toxoplasma gondii tachyzoites, by a specific monoclonal antibody has demonstrated a homogenous distribution of this antigen on the surface of intra- and extracellular tachyzoites at all stages of their endodyogenic development. On living zoites, no redistribution of anti-P30 was obtained, contrasting with the capping obtained with antiserum to T. gondii. Upon invasion of a host cell, however, most of the coat of anti-P30 was shed from preincubated zoites at the level of the moving junction governing the entry of the parasite into the host cell.

Influence of hormones and undernutrition on brain development in newborn rats

High L-thyroxine (T4) and cortisol doses given to rats during the first 8 days of life and on the first day only respectively, produce decrease of body and brain weight and perturbances to brain energy substrates, i.e. glucose and ketone bodies. The same alterations are found in the undernourished rats from the prenatal period. The pituitary GH and TSH is decreased in the T4- and cortisol-injected animals. The plasma ACTH is decreased in the treated cortisol animals at 8, 12 and 22 days of life. The pituitary TSH content is reduced with respect to controls in the undernourished animals from 14 to 70 days of life. From the exposed experiments we suggest an alteration in the hypothalamic-pituitary complex in T4- and cortisol-treated rats, and describe the similarities between the three experimental models.

Different monoclonal antibodies against the component 5 specific for Trypanosoma cruzi

Three murine monoclonal antibodies (I-35/67, II-190/30, III-160/18) produced by immunization against total epimastigote extract or component 5-enriched fractions of Trypanosoma cruzi (Tehuantepec strain) have been demonstrated to recognize the component 5 specific for T. cruzi. By immunofluorescence studies, one of these monoclonal antibodies (I-35/67) was shown to bind to the epimastigote cell surface, and the two others (II-190/30 III-160/18) were preferentially directed against internal subcellular organelles. Immunoprecipitation using these monoclonal antibodies followed by SDS-PAGE analysis, has led to identification of four molecules with apparent molecular weights of 72 Kd, 51 Kd, 43 Kd, and 24 Kd in T. cruzi epimastigotes. Potential uses of these monoclonal antibodies in serological tests and immunochemical analysis of target antigens are discussed.

'Osmosin' in rheumatoid arthritis: interim results

The interim results of an on-going trial in patients with active rheumatoid arthritis are reported. The findings from 17 patients so far treated and followed-up for 4 to 6 weeks suggest that 'Osmosin' (105 mg sodium indomethacin trihydrate), given once daily for the first 2 weeks and twice daily thereafter, is effective in reducing the inflammatory activity of joint disease, as assessed by visual analogue and 5-point semantic severity scales. Analysis showed that there was a strong association between the assessments on the two scales and this was stronger if patients were not conditioned by being allowed to see their previous visual analogue scale assessment.

[Production of monoclonal antibody anti-antigen 5 for Trypanosoma cruzi]

Monoclonal antibodies against Trypanosoma cruzi have been produced by fusion of Sp 2/0 myeloma cells and splenic lymphocytes from BALB/c Mice immunized with a T. cruzi antigenic fraction. Antigenic studies of these monoclonal antibodies have led to the identification of IgG 1 antibody against the component 5 specific for T. cruzi (cellular clone II 190/151). These monoclonal antibodies will give rise not only to new diagnostic and epidemiological perspectives but will also aid in achieving a better understanding of the biological role of this antigen.

Total and cell wall phosphorus content in Bacillus megaterium in phosphate-limited media

A comparative study of the amount of total and cell wall phosphorus in Bacillus megaterium ATCC 33085, grown in media with or without phosphate limitation was carried out. The phosphorus levels were investigated during six successive subcultures. A progressive decrease in total phosphorus was found in cells cultivated in a phosphate-limited medium. A decline in the cell wall phosphorus level was observed starting only from the third subculture in phosphate-limited medium, and no phosphorus was detected in the walls of cells in the fifth subculture.