5-aminolevulinate synthase mRNA levels in the Harderian gland of Syrian hamsters: correlation with porphyrin concentrations and regulation by androgens and melatonin

The levels of 5-aminolevulinate synthase mRNA were investigated in the Harderian glands of male and female Syrian hamsters by using a cDNA clone from rat liver. Female hamsters showed higher levels of mRNA than those in males, while the administration of testosterone to female hamsters led to a reduction in mRNA levels. Castration of male hamsters caused a marked elevation of mRNA levels, whereas both the exposure to constant darkness or melatonin injections to castrated males partially prevented the effects of castration. Porphyrin concentration of Harderian glands showed a strong correlation with the mRNA levels of 5-aminolevulinate synthase in all the animals studied. These results lead to the conclusion that in this system, porphyrin metabolism is controlled through hormonal regulation of 5-aminolevulinate synthase gene expression.

Normally saprobic cryptococci isolated from Cryptococcus neoformans infections

We report two cases in which Cryptococcus laurentii was isolated from surgically resected pulmonary lesions but the cryptococcal cells is tissue reacted positively with a specific fluorescent antibody (FA) conjugate for Cryptococcus neoformans. Both patients had no apparent host defense defects. In both cases, multiple cryptococcal isolates were obtained from tissue, and yeastlike cells consistent with C. neoformans were seen in direct histology. The isolates were identified by assimilation patterns and standard procedures including phenoloxidase reactions. Since C. laurentii was consistently isolated by using stringent procedures, it was considered unlikely that the fungus represented surgical or laboratory contamination. Its presence may be the result of dual infection not detected by FA, but other possible explanations exist. The results show the value of the FA test in diagnostic mycology and call into question previous reports of cryptococci other than C. neoformans as agents of infection.

Chronic administration of melatonin induces changes in porphyrins and in the histology of male and female hamster harderian gland: interrelation with the gonadal status

In this paper, we have investigated the influence of melatonin on the histology and porphyrin content of the Syrian hamster Harderian glands. Daily afternoon injections of 25 micrograms of melatonin to female hamsters for 12 weeks resulted in the discontinuity of estrous cyclicity, a marked decrease in the Harderian gland intraluminal area occupied by porphyrins, and in a significant rise in the number of Type II cells. A similar decrease in porphyrins was observed after 8 weeks of ovariectomy. However, if the melatonin injections were given for only 8 weeks (without inducing gonadal atrophy), no changes were observed in the area occupied by intraluminal porphyrins, suggesting that the effects of melatonin in female Syrian hamsters might be associated with the subsequent gonadal atrophy. Castration of male hamsters induced a significant increase in porphyrins and a clear drop in the number of Type II cells. These changes were totally prevented when melatonin was administered daily from the day of castration. Our results suggest that melatonin, at least in male Syrian hamsters, plays a role in Harderian metabolism, acting directly on the Harderian secretory cells or indirectly through pituitary hormones.

Lindane may enhance nocturnal pineal N-acetyltransferase activity via beta-adrenergic receptors

Lindane, a chlorinated hydrocarbon pesticide, was previously shown to enhance the nighttime rise in pineal N-acetyltransferase (NAT) activity and melatonin as well as serum melatonin levels. The purpose of the present study was to test whether lindane acts on the pineal gland by means of a beta-adrenergic receptor mechanism. Whereas lindane (total dose 17.8 mg/kg b.wt. over 6 days) by itself significantly augmented the nocturnal levels of pineal NAT activity in otherwise untreated rats, the pesticide was ineffective in reference to this enzyme when it was given in conjunction with the beta-adrenergic receptor antagonist propranolol (20 mg/kg b.wt., one hour before lights off). The augmentation of NAT activity by lindane also caused significant reductions in pineal serotonin (5-HT) and 5-hydroxyindole acetic acid (5-HIAA); again, both these responses were blocked by propranolol treatment. Neither pineal 5-hydroxytryptophan nor pineal or serum melatonin levels were significantly changed as a result of either lindane or propranolol treatment. The results are consistent with the idea that lindane influences pineal 5-HT metabolism either at the level of the beta-adrenergic receptor or via the sympathetic innervation to the pineal gland.

Effect of weight loss on insulin sensitivity and cardiovascular risk factors in glucose tolerant and intolerant obese subjects

We observed 170 obese patients during 55 weeks in order to study the influence of insulin resistance and insulin sensitivity on cardiovascular risk factors in such patients as well as the changes occurring on these subjects as a result of weight loss. At the beginning of the study, the patients were divided into two groups, according to the results of an oral glucose tolerance test (OGTT) performed with 75 g of glucose: Group A, glucose tolerant subjects (n = 81), Group B, glucose intolerant subjects (n = 89). Initially Group B patients showed higher values for fasting blood glucose, 2 h after OGTT, systolic and diastolic blood pressure, cholesterol, triglycerides and cholesterol/HDL-cholesterol ratio when compared to Group A patients (p less than 0.05). Fasting and 1 h-post glucose load serum insulin levels in both Group A and Group B patients were higher than those found out in non over-weight tolerant subjects, but there were no differences between both groups. The serum glucose descent slope after an insulin tolerance test (ITT) was lower for group B than for group A (p less than 0.05), whereas both groups demonstrated lower descent slopes than non overweight tolerant subjects (p less than 0.05). After a 55 weeks follow-up period, the patients in Group A had lost 4.6 +/- 0.7 kg and those in Group B 6.2 +/- 1.1 kg. In both groups, the values for SBP, DBP, FBG, triglycerides and cholesterol/HDL-cholesterol ratio had dropped significantly, with a rise in the HDL-cholesterol level.(ABSTRACT TRUNCATED AT 250 WORDS)

Low peptic ulcer and high gastric cancer prevalence in a developing country with a high prevalence of infection by Helicobacter pylori

We compared the prevalence rates of peptic ulcer (duodenal and gastric) and gastric cancer in 1,796 dyspeptic Peruvian patients with those reported in 2,883 similar patients from developed countries. The prevalence of total peptic ulcer was significantly lower, and that of gastric cancer significantly higher, in the Peruvian patients. The prevalence of gastric ulcer was lower but not significantly so. We deduced that the significantly lower prevalence of total peptic ulcer was directly related to the low prevalence rate of duodenal ulcer. We hypothesize that the reason for these differences was probably a higher prevalence of Helicobacter pylori-associated chronic atrophic gastritis with hypochlorhydria in the Peruvian patients. Hypochlorhydria decreases the predisposition to peptic ulcer (especially duodenal ulcer), and chronic atrophic gastritis may predispose an individual to gastric cancer.

Human in vivo-induced spontaneous IgG-secreting cells from tonsil, blood and bone marrow exhibit different phenotype and functional level of maturation

The subset of human spontaneous IgG-secretion cells consists of mature B lymphocytes which are capable of active and high rate IgG production in vitro without the need for additional stimuli. Therefore, such a cell subset provides a useful model for studying the terminal stages of B-cell maturation. The present work analyses the phenotypic and functional characteristics of spontaneous IgG secreting cells obtained from tonsil, blood and bone marrow. The tonsilar cell subset was CD9+ CD20+ CD19+ CD38+/-, the blood cell subset CD9- CD20- CD19+ CD38+/- and bone marrow cells were CD9- CD20- CD19+/- CD38+. The three cell subsets required de novo RNA and protein synthesis for IgG secretion to occur. Tonsilar and blood, but not bone marrow, subsets also required DNA synthesis to undergo IgG secretion. Kinetics studies revealed that IgG production by tonsil and blood cells reached a plateau after 3 days of culture. In contrast, the bone marrow cell subset secreted IgG in a linear fashion for 2 weeks. These results indicate that spontaneous IgG-secreting cells from different organs exhibit functional and phenotypic heterogeneity.

Harderian gland porphyrin, lysosomal and type II 5'-deiodinase rhythms in Sprague-Dawley and Fischer-344 rats kept under chronic long- or short-photoperiod conditions

1. Harderian gland porphyrin concentrations were 1.5-fold higher in Fischer-344 male rats than in Sprague-Dawley male rats and there were no differences due to exposure to LD 14:10 (LP) or LD 10:14 (SP) lighting conditions for 8 weeks in either strain. 2. 24-hr periodic regression analyses of porphyrin concentration detected a significant rhythm in both lighting conditions in both strains, with no differences in acrophase due to lighting conditions. 3. In both strains, porphyrin levels were highest in the late phase-early dark period and fell during the early part of the dark period. 4. Acid phosphatase activity did not vary with time (circadian rhythm), strain or photoperiodic lighting condition. 5. Circadian rhythms in beta-glucuronidase, alpha-mannosidase and hexosaminidase activity were present in some instances, but, probably due to the low amplitude to these rhythms, a consistent effect of strain or housing condition was not found. When 24-hr rhythms were observed in either strain, the acrophase occurred during the afternoon-early evening daylight period. 6. A significant effect of strain on mean values of type II 5'-deiodinase activity was noted in Fischer-344 rats. 7. Significant rhythms in type II 5'-deiodinase activity were found in both strains exposed to LD 10:14.

Identification of the multidrug resistance-related membrane glycoprotein as an acceptor for cyclosporine

The immunosuppressive agent cyclosporine A (CSA) has been shown to reverse multidrug resistance (MDR) in malignant cells. In the present study, a 3H-cyclosporine diazirine analogue (3H-PL-CS) was used to photolabel viable MDR cells. The 170 kDa membrane P-glycoprotein, which functions as a drug efflux pump, was strongly labeled. The binding of 3H-cyclosporine diazirine analogue to P-glycoprotein was competable by excess cyclosporine A and by the nonimmunosuppressive cyclosporine H. These results suggest that cyclosporine reverses the MDR phenotype by binding directly to P-glycoprotein and that this binding is not dependent on the immunosuppressive potential of the cyclosporine derivative. The identification of P-glycoprotein as a cyclosporine binding protein has obvious implications for cancer chemotherapy.

Indole and porphyrin content of the Syrian hamster harderian glands during the proestrous and estrous phases of the estrous cycle

Porphyrin and indole metabolism was studied in the Harderian glands of Syrian hamsters during the proestrous and estrous stages of the estrous cycle. Porphyrins remained unaltered during these stages, but levels of different indoles (5-hydroxytryptophan, 5-hydroxytryptamine, N-acetyl-5-hydroxytryptamine, and 5-hydroxyindole acetic acid) exhibited pronounced changes during the dark:light period in both proestrous and estrous. There was a strong parallelism between 5-hydroxytryptamine, N-acetyl-5-hydroxytryptamine and 5-hydroxyindole acetic acid levels. Hydroxytryptophan rhythms appeared slightly shifted from those of the other indoles. Immunoreactive melatonin present in the Harderian glands did not show a significant day-night change during the stages studied.

Phospholipase A2 activation and autoinduction of tumor necrosis factor gene expression by tumor necrosis factor

Tumor necrosis factor (TNF) acts via a cell surface receptor to induce a variety of cellular events including cytolysis, differentiation, and mitogenesis. The mechanisms underlying the cell specific actions of TNF are not known. In the present study, postreceptor events associated with the autoinduction of TNF expression were examined in HL-60 cells. There was no detectable alteration in phospholipase C activity as measured by inositol phosphate generation or release of choline metabolites following TNF stimulation. However, TNF increased the release of arachidonic acid metabolites from HL-60 cells. This increase in arachidonic acid metabolism was associated with a 40% increase in phospholipase A2 activity. Furthermore, the release of arachidonic acid metabolites was blocked by inhibitors of phospholipase A2. Taken together, these findings indicated that TNF stimulates phospholipase A2 and arachidonic acid metabolism in HL-60 cells. The results also demonstrate that TNF expression is induced 15-30 min after stimulation with TNF and that this effect is associated with an increase in the rate of TNF transcription. This autoinduction of TNF mRNA was blocked by inhibitors of phospholipase A2. While the cyclooxygenase inhibitor indomethacin had no detectable effect, ketoconazole and nordihydroguaiaretic acid, inhibitors of lipoxygenase, also blocked the induction of TNF expression by TNF. These findings suggest that phospholipase A2 and lipoxygenase activity are required for the transcriptional activation of TNF gene expression associated with TNF stimulation of HL-60 cells.

Endocarditis due to ampicillin-resistant nontyphoid Salmonella: cure with a third-generation cephalosporin

A case of ampicillin-resistant salmonella bacteremia complicated by endocarditis in a 78-year-old man is presented. Previous rheumatic valvular heart disease and the lack of response to initial treatment with chloramphenicol prompted us to consider this diagnosis. There was a good clinical response after treatment with ceftriaxone alone and corresponding improvement on the echocardiogram. This case demonstrates the possible endovascular complications of salmonella bacteremia in elderly people and that endocarditis should be included among the invasive infections due to ampicillin-resistant Salmonella that could potentially be treated with the newer cephalosporins.

Emergency department deaths

This study reviews 186 deaths resulting from trauma in a 2-year period in the Charity Hospital of Louisiana at New Orleans Accident Room in order to evaluate problems in prehospital and hospital resuscitative care. All subjects underwent autopsy, and only six were found to have injuries compatible with survival. Three of these were late arrivals (by transfer or self-imposed delay) and died of protracted hemorrhage. Only three deaths occurring in the Emergency Department itself were found to have been potentially preventable. The important factors in maximizing survival of trauma patients remain rapid transport; immediate, appropriate, rapid evaluation; and quick diagnosis, resuscitation, and definitive therapy. These require a well-trained emergency medical ambulance service delivering patients quickly to a hospital designed to handle trauma patients. One person, preferably a general surgeon with trauma experience, should supervise and monitor the patient continually until the resuscitation phase and all diagnostic tests are completed and definitive therapy is initiated.

The purine-cytosine permease gene of Saccharomyces cerevisiae: primary structure and deduced protein sequence of the FCY2 gene product

A 2.1 kb DNA segment carrying the purine-cytosine permease gene (FCY2) of Saccharomyces cerevisiae was sequenced, the primary structure of the protein (533 amino acids) deduced and a folding pattern in the membrane is proposed for the permease protein. Expression of the FCY2 gene product requires a functional secretory pathway and is reduced in mnn9, a mutant strain deficient in outer chain glycosylation. The FCY2 gene was mapped on the right arm of chromosome V close to the HIS1 gene.

Distribution of carboxypeptidase H messenger RNA in rat brain using in situ hybridization histochemistry: implications for neuropeptide biosynthesis

Carboxypeptidase H is an exopeptidase which is highly specific for C-terminal basic amino acids and thought to play a role in neuropeptide biosynthesis. The distribution of carboxypeptidase H mRNA was examined in adult rat brain using in situ hybridization histochemistry. Enzyme transcripts were detected in all major brain areas. Very high levels of carboxypeptidase H mRNA were found in the hippocampus associated with pyramidal cells. Other brain regions showed varied levels of labelling, ranging from high levels in the magnocellular cells of hypothalamic nuclei to very low levels in the striatum. The appearance of enzyme transcripts throughout brain supports a role for this enzyme in the biosynthesis of many neuropeptides. The expression of transcripts in certain ventricular ependymal cells identified them as a new potential peptidergic cell type. The variations in levels of expression of carboxypeptidase H mRNA may reflect differences in peptidergic activity in different neuronal systems.

Programme of education for obese patients. Preliminary results after one year

We have evaluated the effects of a Programme of education for Obese Patients with a duration of 12 hours on weight loss and the modification of other indices for cardiovascular risk in 88 obese patients, during the first year of therapy. The BMI dropped from 33.1 +/- 0.2 Kg/m2 to 31.7 +/- 0.7 (p less than 0.01) and 30.9 +/- 0.7) (p less than 0.01) at 5 and 10 weeks respectively, stabilizing subsequently at 35 and at 55 weeks. This was accompanied by a decrease of the triglycerides levels (141 +/- 9 vs 111 +/- 6 mg/dl; p less than 0.01) and of the total cholesterol/HDL-cholesterol ratio (4.7 +/- 0.3 vs 4.2 +/- 0.12; p less than 0.05), as well as of the values for systolic blood pressure (143 +/- 3 vs 121 +/- 3 mm Hg; p less than 0.05) and diastolic blood pressure 81 +/- 2 vs 64 +/- 1 mm Hg; p less than 0.01) at the end of the study. In terms of OGTT, initially 23 patients were classified as diabetic (BMI 32 +/- 0.9 Kg/m2), 25 presented intolerance to carbohydrates (BMI 34.1 +/- 1.6 Kg/m2) and 40 were normal (BMI 33.2 +/- 1.2 Kg/m2). The weight loss in the first 5 weeks was less in patients with diabetes then in those with carbohydrate intolerance and in the normal patients (2.2 vs 3.7 vs 5.9 Kg; p less than 0.01). From the 10th week on no differences were recorded.(ABSTRACT TRUNCATED AT 250 WORDS)

Blockade of endothelin-induced contractions by dichlorobenzamil: mechanism of action

Contractions of intact rat aortic rings induced by endothelin were totally inhibited by the amiloride analogue dichlorobenzamil (DCB) at concentrations known to block Na-Ca exchange (IC50 = 30 microM). Amiloride (100 microM) was ineffective. Ca-channel blockers and a K-channel opener elicited only partial inhibition. These results could indicate that the Na-Ca exchanger plays an important role in endothelin-induced contractions. Endothelin, however, had no effect on the kinetics of the exchanger, and, in addition, contractions also occurred in Na-depleted vessels. The endothelin-induced contractions produced by Ca release from intracellular pools were also completely inhibited by DCB. In fact, the latter compound was found to block contractions induced by Ca itself in the presence of Ca ionophore or detergent. We conclude that DCB acts directly on Ca-induced activation of myofilaments in smooth muscle.

Evaluation of a competitive antibody enzyme immunoassay for specific diagnosis of Chagas' disease

A competitive enzyme immunoassay based on the use of a monoclonal antibody (MAb) specific for "component 5" of Trypanosoma cruzi was evaluated. The antigenicity and immunogenicity of this component has been observed in natural and experimental infections. The studies were conducted in an area of Bolivia where mixed infections with Leishmania braziliensis are frequent and present a problem in the accurate diagnosis of T. cruzi infections. The specificity and sensitivity of this assay as compared to the indirect immunofluorescence and ELISA tests were demonstrated. The present test has proved to be more specific than the immunofluorescence and ELISA tests.

Comparative functional study of colostral macrophages from mothers delivering preterm and at term

Number and function of milk macrophages (MM) from 30 healthy mothers delivering preterm (mean gestational age 33 weeks) were compared with those obtained from 92 mothers with term delivery. The average concentration of MM in colostrum did not differ in the two groups: 0.55 x 10(6)/ml (preterm) and 0.42 x 10(6)/ml (term). Preterm MM showed the same activity as term MM in all three assayed functions (phagocytosis, chemotaxis and IL-1 secretion). Phagocytic activity, and impaired migratory motility and IL-1 secretion were significantly increased both in preterm and term MM in comparison with the activity in less mature blood monocytes. Thus it appears that preterm MM are, like term MM, a fully mature tissue macrophage population and therefore we suggest that with regard to MM both preterm and term colostrum are comparable, at least in the gestational age tested.

Liquid-chromatographic determination of free and total 3,4-dihydroxyphenylglycol and 3-methoxy-4-hydroxyphenylglycol in urine

We describe the conjoint measurement in urine of the alcoholic catecholamine metabolites 3,4-dihydroxyphenylglycol (DHPG) and 3-methoxy-4-hydroxyphenylglycol (MHPG). The method involves extraction with ethyl acetate and back-extraction into acetic acid (MHPG), followed by adsorption onto alumina (DHPG). The separation is performed by reversed-phase liquid chromatography with column switching and amperometric detection. Total (free plus conjugated) compounds are determined after a 24-h enzymatic hydrolysis. Twelve-hour excretion values for normal and hypertensive subjects are given, together with results obtained for patients with pheochromocytoma, chemodectoma, and congenital dopamine-beta-hydroxylase deficiency. The assay is sensitive, reproducible, and free of interferences, and may lead to a better understanding of overall catecholamine metabolism in health and disease.

Liquid-chromatographic determination of free and total 3,4-dihydroxyphenylglycol and 3-methoxy-4-hydroxyphenylglycol in urine

We describe the conjoint measurement in urine of the alcoholic catecholamine metabolites 3,4-dihydroxyphenylglycol (DHPG) and 3-methoxy-4-hydroxyphenylglycol (MHPG). The method involves extraction with ethyl acetate and back-extraction into acetic acid (MHPG), followed by adsorption onto alumina (DHPG). The separation is performed by reversed-phase liquid chromatography with column switching and amperometric detection. Total (free plus conjugated) compounds are determined after a 24-h enzymatic hydrolysis. Twelve-hour excretion values for normal and hypertensive subjects are given, together with results obtained for patients with pheochromocytoma, chemodectoma, and congenital dopamine-beta-hydroxylase deficiency. The assay is sensitive, reproducible, and free of interferences, and may lead to a better understanding of overall catecholamine metabolism in health and disease.

Iron deficiency anemia and steady-state work performance at high altitude

Thirty-seven young adult male highland residents at 3,600-4,100 m in La Paz, Bolivia, performed short-duration cycle ergometry at 60, 80, and 100% of maximal voluntary O2 consumption (VO2max). Three groups of subjects representing the high-altitude population mean hemoglobin (Hb), the 10th percentile Hb, and below the 1st percentile were examined to test the hypothesis that the relationship of exercise performance to Hb concentration is similar to those relationships established at low altitude. Anemic individuals (n = 8) had 23% lower voluntary VO2max and 28% lower maximal work loads compared with controls (n = 17) or marginally anemic subjects (n = 12) although the relationship of VO2 to work load was similar. Anemic individuals maintained significantly higher arterial O2 partial pressures and Hb saturations during heavy exercise (90 +/- 0.5 vs. 85 +/- 0.6%) in conjunction with a greater heart rate up to maximal effort. A significantly decreased erythrocyte 2,3-diphosphoglycerate (2,3-DPG)-to-Hb molar ratio (0.70 +/- 0.04 vs. 1.12 +/- 0.06), suggestive of a left-shifted dissociation curve in anemics, is in contrast to the expected right-shifted curve. Moderate anemics were similar to controls. Anemic individuals did not differ in arterial lactate concentration from controls at absolute work loads; anemics had significantly lower arterial lactate concentrations at maximal effort than controls with no differences in the work load-to-lactate relationship. In conclusion, O2 transport during exercise at high altitude seems unaffected by the Hb concentrations as low as the 10th percentile of the population mean.(ABSTRACT TRUNCATED AT 250 WORDS)

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.