Biological variation of interleukin 6 (IL-6) and soluble interleukin 2 receptor (sIL2R) in serum of healthy individuals

The biological variation of interleukin 6 (IL-6) and soluble interleukin 2 receptor (sIL2R), measured by automated enzyme immunoassay, in fifteen subjects studied at regular monthly intervals over a period of 6 consecutive months was measured. The mean and standard deviation (SD), within-subject CV, between-subject CV, individuality index (II) and reliability coefficient (R) were as follow: for sIL2R 571 (231) U/ml, 5.84%, 38.81%, 0.21 and 0.93; and for IL-6 1.43 (0.9) pg/ml, 48.48%, 39.38%, 1.44, and 0.37. The data indicate a relatively high between-subject CV, quite similar in both cases, and a within-subject CV much higher for IL-6 than for sIL2R. Thus, reference values can be used for diagnosis for IL6 (high II), while not for sIL2R (low II). However, the low R for IL-6 implies that more than one measurement are needed. sIL2R has a very high R and a relatively small critical differences, a circumstance appropriate for follow-up.

Lack of cross-reactivity of anti-DNA antibodies to ribonucleoproteins in a new commercial blot system for specific ANAs

Anti-DNA antibodies often exhibit cross-reactivity. It has been observed that anti-DNA antibodies cross-react with A and D snRNP proteins in an in-house developed Western blot assay but do not cross-react with native U1RNP in ELISA or immunoprecipitation experiments. We have analyzed the cross-reactivity of anti-DNA antibodies to snRNP A and D in a recently developed commercial blot assay (InnoLIA, Innogenetics). In our experience anti-DNA antibodies do not cross-react with proteins A and D in this blot system. Hence this new blot system avoids the cross-reactivity problems in the assessment of antinuclear antibody specificity for both Sm and U1snRNP.

Intestinal leiomyosarcoma as the cause of severe hemoperitoneum

Leiomyosarcomas represent 10-20% of malignant tumors in the small bowel and 1% of those located in the large bowel. These tumors have aspecific symptoms depending on their size, location and histology. Intestinal leiomyosarcomas may be the cause of numerous types of surgical emergency. We report 2 cases of intestinal leiomyosarcoma in the jejunum and transverse colon. Both were diagnosed during an emergency exploratory celiotomy. The clinical features on admission were similar to those of acute abdomen. The main cause of surgical emergency was an extremely rare complication of gastrointestinal leiomyosarcoma: a severe hemoperitoneum. We briefly describe the surgical emergencies caused by intestinal leiomyosarcomas as well as the surgical methods employed in these cases.

Role of 17beta-estradiol and/or progesterone on insulin sensitivity in the rat: implications during pregnancy

The mechanism for the development of insulin resistance in normal pregnancy is complex and is associated with serum levels of both progesterone and 17beta-estradiol. However, it remains unclear whether estrogens alone or progestins alone can cause insulin resistance, or whether it is a combination of both which produces this effect. We attempted to determine the role played by progesterone and/or 17beta-estradiol on the phenomena of sensitivity to insulin action that take place during pregnancy in the rat. Ovariectomized rats were treated with different doses of progesterone and/or 17beta-estradiol in order to simulate the plasma levels in normal pregnant rats. A euglycemic/hyperinsulinemic clamp was used to measure insulin sensitivity. At days 6 and 11, vehicle (V)- and progesterone (P)-treated groups were more insulin resistant than 17beta-estradiol (E)- and 17beta-estradiol+progesterone (EP)-treated groups. Nevertheless, at day 16, the V, EP and E groups were more resistant to insulin action than the P group. On the other hand, the V, EP and E groups were more insulin resistant at day 16 than at day 6, whereas the P group was more insulin resistant at day 6 than at day 16. Our results seem to suggest that the absence of female steroid hormones gives rise to a decreased insulin sensitivity. The rise in insulin sensitivity during early pregnancy, when the plasma concentrations of 17beta-estradiol and progesterone are low, could be due to 17beta-estradiol. However, during late pregnancy when the plasma concentrations of 17beta-estradiol and progesterone are high, the role of 17beta-estradiol could be to antagonize the effect of progesterone, diminishing insulin sensitivity.

Structural differences between Saccharomyces cerevisiae ribosomal stalk proteins P1 and P2 support their functional diversity

The eukaryotic acidic P1 and P2 proteins modulate the activity of the ribosomal stalk but playing distinct roles. The aim of this work was to analyze the structural features that are behind their different function. A structural characterization of Saccharomyces cerevisaie P1 alpha and P2 beta proteins was performed by circular dichroism, nuclear magnetic resonance, fluorescence spectroscopy, thermal denaturation, and protease sensitivity. The results confirm the low structure present in both proteins but reveal clear differences between them. P1 alpha shows a virtually unordered secondary structure with a residual helical content that disappears below 30 degrees C and a clear tendency to acquire secondary structure at low pH and in the presence of trifluoroethanol. In agreement with this higher disorder P1 alpha has a fully solvent-accessible tryptophan residue and, in contrast to P2 beta, is highly sensitive to protease degradation. An interaction between both proteins was observed, which induces an increase in the global secondary structure content of both proteins. Moreover, mixing of both proteins causes a shift of the P1 alpha tryptophan 40 signal, pointing to an involvement of this region in the interaction. This evidence directly proves an interaction between P1 alpha and P2 beta before ribosome binding and suggests a functional complementation between them. On a whole, the results provide structural support for the different functional roles played by the proteins of the two groups showing, at the same time, that relatively small structural differences between the two stalk acidic protein types can result in significant functional changes.

Vaccinia virus infection disrupts microtubule organization and centrosome function

We examined the role of the microtubule cytoskeleton during vaccinia virus infection. We found that newly assembled virus particles accumulate in the vicinity of the microtubule-organizing centre in a microtubule- and dynein-dynactin complex-dependent fashion. Microtubules are required for efficient intracellular mature virus (IMV) formation and are essential for intracellular enveloped virus (IEV) assembly. As infection proceeds, the microtubule cytoskeleton becomes dramatically reorganized in a fashion reminiscent of overexpression of microtubule-associated proteins (MAPs). Consistent with this, we report that the vaccinia proteins A10L and L4R have MAP-like properties and mediate direct binding of viral cores to microtubules in vitro. In addition, vaccinia infection also results in severe reduction of proteins at the centrosome and loss of centrosomal microtubule nucleation efficiency. This represents the first example of viral-induced disruption of centrosome function. Further studies with vaccinia will provide insights into the role of microtubules during viral pathogenesis and regulation of centrosome function.

Visualizing the spindle checkpoint in Drosophila spermatocytes

The spindle assembly checkpoint detects defects in spindle structure or in the alignment of the chromosomes on the metaphase plate and delays the onset of anaphase until defects are corrected. Thus far, the evidence regarding the presence of a spindle checkpoint during meiosis in male Drosophila has been indirect and contradictory. On the one hand, chromosomes without pairing partners do not prevent meiosis progression. On the other hand, some conserved components of the spindle checkpoint machinery are expressed in these cells and behave as their homologue proteins do in systems with an active spindle checkpoint. To establish whether the spindle checkpoint is active in Drosophila spermatocytes we have followed meiosis progression by time-lapse microscopy under conditions where the checkpoint is likely to be activated. We have found that the presence of a relatively high number of misaligned chromosomes or a severe disruption of the meiotic spindle results in a significant delay in the time of entry into anaphase. These observations provide the first direct evidence substantiating the activity of a meiotic spindle checkpoint in male Drosophila.

Transport and metabolism of serotonin in the human placenta from normal and severely pre-eclamptic pregnancies

We have attempted to elucidate the possible participation of serotonin as an etiological factor in pre-eclampsia. The transport of serotonin into vesicles from the maternal-facing brush border membrane was measured, as well as the metabolism induced by monoamine oxidase (MAO) in placental homogenate obtained from normal-term and severely pre-eclamptic placentas. Kinetic analysis of serotonin uptake by the placental brush border membrane of the syncytiotrophoblast between normally pregnant and severely pre-eclamptic subjects showed no significant difference (similar Vmax and Km values). However, the metabolism of serotonin was significantly higher in placental homogenate from normal pregnancies than in placentas from severely pre-eclamptic pregnancies. These findings suggest that the higher plasma-free serotonin levels observed in severe pre-eclampsia are mainly due to a reduction in MAO-A activity and not limited by the rate of serotonin uptake into the cells.

Intracellular Ca(2+) stores in chemoreceptor cells of the rabbit carotid body: significance for chemoreception

The notion that intracellular Ca(2+) (Ca(i)(2+)) stores play a significant role in the chemoreception process in chemoreceptor cells of the carotid body (CB) appears in the literature in a recurrent manner. However, the structural identity of the Ca(2+) stores and their real significance in the function of chemoreceptor cells are unknown. To assess the functional significance of Ca(i)(2+) stores in chemoreceptor cells, we have monitored 1) the release of catecholamines (CA) from the cells using an in vitro preparation of intact rabbit CB and 2) the intracellular Ca(2+) concentration ([Ca(2+)](i)) using isolated chemoreceptor cells; both parameters were measured in the absence or the presence of agents interfering with the storage of Ca(2+). We found that threshold [Ca(2+)](i) for high extracellular K(+) (K(e)(+)) to elicit a release response is approximately 250 nM. Caffeine (10-40 mM), ryanodine (0.5 microM), thapsigargin (0.05-1 microM), and cyclopiazonic acid (10 microM) did not alter the basal or the stimulus (hypoxia, high K(e)(+))-induced release of CA. The same agents produced Ca(i)(2+) transients of amplitude below secretory threshold; ryanodine (0.5 microM), thapsigargin (1 microM), and cyclopiazonic acid (10 microM) did not alter the magnitude or time course of the Ca(i)(2+) responses elicited by high K(e)(+). Several potential activators of the phospholipase C system (bethanechol, ATP, and bradykinin), and thereby of inositol 1,4,5-trisphosphate receptors, produced minimal or no changes in [Ca(2+)](i) and did not affect the basal release of CA. It is concluded that, in the rabbit CB chemoreceptor cells, Ca(i)(2+) stores do not play a significant role in the instant-to-instant chemoreception process.

Purification and properties of a lipase from Cephaloleia presignis (Coleoptera, chrysomelidae)

A novel lipase from the insect Cephaloleia presignis was purified by a procedure involving ammonium sulphate precipitation, and Phenyl Toyopearl 650M, DEAE-5PW and hydrophobic-interaction column chromatographies. The purified lipase was homogeneous with a molecular mass of 31000 Da by SDS/PAGE and of 29000 Da by gel filtration on a Superose 12 column. The enzyme was identified as a glycoprotein with a pI of 6.9. The enzyme unspecifically liberated short-chain to long-chain fatty acids from p-nitrophenyl esters, methyl esters and triglycerides. The N-terminal 28 amino acid residues were determined as AGTLGYATRHVLPIFTLDDYTGSNEMWG, which showed no similarity with known proteins, suggesting that the purified lipase may belong to a novel class of hydrolases.

[Nonconvulsive status epilepticus of frontal origin. A case report]

INTRODUCTION

Nonconvulsive status epilepticus (NCSE) of frontal origin is a form of partial status epilepticus which has rarely been well-documented. The inespecificity of the symptoms contribute frequently to its misinterpretation being the EEG the most useful tool to make an accurate diagnosis.

CLINICAL CASE

We report a 53-year-old woman who suffered from two generalized tonic-clonic seizures secondary to a left frontal hematoma in 1994. Onset of treatment with carbamazepine was followed by a complete control of seizures. After remaining seizure-free during four years, antiepileptic therapy was discontinued. By June 1999, she presented with a prolonged confusional state having a generalized tonic-clonic seizure at the emergency room. At that moment, a computed tomography (CT) scan was normal. Generalized seizures were controlled with phenytoin, however, the patient remained confused having occasionally episodes of turning of the head and eyes to the right side. Ictal EEG examination showed recurrent bilateral frontopolar, frontocentral and frontotemporal epileptiform discharges with a left frontal focal onset. The diagnosis of NCSE of frontal origin was made. Despite several anticonvulsant combinations, confusional state remained unchanged and she was transferred to the intensive care unit for sedation with propofol and mydazolam. On the following days, she experienced a marked improvement and EEG showed a few frontal spikes and sharp waves but without evidence of electrographic status epilepticus. The patient was finally discharged and remains seizure-free on phenytoin therapy.

CONCLUSIONS

Our clinical and EEG findings are in keeping with the diagnosis of NCSE of frontal origin. A severe confusional state was the most prominent symptom and EEG was essential for the diagnosis.

Musculoskeletal infections in intravenous drug addicts: report of 34 cases with analysis of microbiological aspects and pathogenic mechanisms

OBJECTIVE

To analyse characteristics of musculoskeletal infections in Spanish intravenous (i.v.) drug addicts.

METHODS

A retrospective analysis of 34 medical records was carried out and the aetiologic agent was confirmed in all cases.

RESULTS

The mean age was 26 years and the sex ratio was 25M/9F. Twenty-four patients were HIV-positive and 10 HIV-negative. There were no differences between the 2 subgroups. Septic arthritis, seen in 27 cases (79%), was the most common type of infection. Axial involvement was present in 23 cases (67%). The organisms isolated included Staphylococcus aureus (25 cases), Candida albicans (3 cases), Mycobacterium tuberculosis (2 cases), and Neisseria gonorrhoeae, Salmonella typhi, Staphylococcus epidermidis and Streptococcus pyogenes in one case each. Candida albicans affected the sternocostal joints. Laboratory data showed non-specific findings. The outcome was mostly good and only one patient died.

CONCLUSION

Human immunodeficiency virus does not affect characteristics of musculoskeletal infections in i.v. drug addicts. Staphylococcus aureus is the most frequently isolated pathogen in this population.

Mechanisms of endothelin-1-induced contraction in isolated placental veins from normal full-term and preterm pregnancies

This study characterizes the reactivity of human chorionic plate vein in full-term (39.4+/-0.3 weeks of gestation) and preterm (34.4+/-0.6 weeks of gestation) pregnancy to endothelin-1 (ET-1) and attempts to characterize ET-1 receptor subtype, and the contribution of nitric oxide and cyclooxygenase products in these responses. In placental veins from full-term and preterm pregnant women, cumulative addition of ET-1 (10(-10)-10(-6) M) caused marked and long-lasting concentration-dependent contractile responses. The mean EC(50) and E(max) values for ET-1-induced venoconstriction did not differ between the full-term and preterm pregnancy groups. In the veins from preterm placental preparations, the ET(A) receptor-selective antagonist cyclo(D-alpha-aspartyl-L-propyl-D-valyl-L-leucyl-D-tryptophyl (BQ123) reduced the ET-1-induced contraction by 28.6+/-2.4%, compared to a decline in tension of 51.2+/-4.2% in the full-term placental vessels. The ET(B) receptor-selective antagonist, N-[N-[N-[2,6-dimethyl-1piperidinyl)carbonyl]-4-methyl-L-leucyl]-1-(methoxycarbonyl)-D-tryptophyl]-D-norleucinemonosodium (BQ788), did not influence ET-1-induced contraction in placental vein from both pregnancy groups in terms of maximal contraction and sensitivity. Pretreatment with the cyclooxygenase inhibitor, indomethacin (1 microM) and the nitric oxide synthase inhibitor N(w)-nitro-L-arginine (NOLA, 100 microM) did not significantly affect either the EC(50) or the maximum contraction to ET-1 in veins from normal full-term and preterm preparations. The results of this study suggest that there is no correlation between ET-1-induced vasoconstriction and gestational age and that this vasoconstriction is mediated predominantly via ET(A) receptor subtype in both groups of pregnant women, independent of NO and eicosanoids.

Protein traps: using intracellular localization for cloning

A much-sought goal - the rapid cloning of genes whose protein products have specific intracellular localizations - has now been made possible. A visual screen of cells expressing fusions between coding DNA sequences and a reporter, such as green-fluorescent protein (GFP) or beta-galactosidase, identifies cells with the pattern of interest. The DNA sequences encoding these targeted fusions can then be cloned either directly from these cells or by repeated rounds of screening and subdivision of library pools. It is expected that systematic screenings based on these methods will identify additional components for every compartment and define new domains, thus facilitating a more comprehensive understanding of the cellular architecture.

Hsp90 is a core centrosomal component and is required at different stages of the centrosome cycle in Drosophila and vertebrates

To determine the molecular composition of the centrosome of a higher eukaryote, we carried out a systematic nano-electrospray tandem or MALDI mass spectrometry analysis of the polypeptides present in highly enriched preparations of immunoisolated Drosophila centrosomes. One of the proteins identified is Hsp83, a member of the highly conserved Hsp90 family including chaperones known to maintain the activity of many proteins but suspected to have other essential, unidentified functions. We have found that a fraction of the total Hsp90 pool is localized at the centrosome throughout the cell cycle at different stages of development in Drosophila and vertebrates. This association between Hsp90 and the centrosome can be observed in purified centrosomes and after treatment with microtubule depolymerizing drugs, two criteria normally used to define core centrosomal components. Disruption of Hsp90 function by mutations in the Drosophila gene or treatment of mammalian cells with the Hsp90 inhibitor geldanamycin, results in abnormal centrosome separation and maturation, aberrant spindles and impaired chromosome segregation. This suggests that another role of Hsp90 might be to ensure proper centrosome function.

Analgesic efficacy and bioavailability of ketorolac in postoperative pain: a probability analysis

BACKGROUND

The analgesic efficacy and bioavailability of 30 mg intramuscular ketorolac was studied in 24 patients with severe or very severe postoperative pain.

METHODS

Pain and pain relief were determined by a five-point verbal rating scale and data were submitted to a probability analysis. Ketorolac plasma levels were determined by high-performance liquid chromatography.

RESULTS

Two patients chose not to finish the study; 22 patients completed the study achieving at least good pain relief. Of these 22 patients, 13 reached complete pain relief. Ketorolac was rapidly absorbed. Notwithstanding, pain relief increased gradually, showing considerable delay with regard to plasma concentrations. Analysis of the probability-time curves revealed that 25% of the patients obtained moderate pain relief at 7 min after ketorolac administration, 50% at 11 min, 75% at 29 min, and 95% at 60 min. Good pain relief was achieved in 25, 50, and 75% of the patients at 1.1, 1.8, and 2.7 h, respectively. Complete pain relief was achieved in 25% and 50% of the patients at 2.6 h and 3.7 h, respectively. The probability of exhibiting an acceptable pain relief in responsive patients for more than 5 h was 0.97. No serious side effects were detected.

CONCLUSIONS

Results show that 30 mg intramuscular ketorolac is an adequate treatment for postoperative pain in the Mexican population. Therefore, the use of higher doses is not justified. Due to gradual installation of analgesia, administration of additional analgesic medication before 1 h is not recommended.

Developmental changes in chemoreceptor nerve activity and catecholamine secretion in rabbit carotid body: possible role of Na+ and Ca2+ currents

In order to better understand the post-natal increase in peripheral chemoreceptor responsiveness to hypoxia, chemoreceptors of newborn (1-2 days) and older (10-12 days, 30 days, adult) rabbits were isolated and superfused, in vitro. The free tissue catecholamine concentration was measured using carbon-fiber voltammetry and pauci-fiber nerve activity was recorded from the sinus nerve during stimulation (4 min) with graded hypoxia or increased potassium. Both the peak catecholamine and peak nerve responses to stimulation with 10% and 0% oxygen increased with age, particularly between 10 and 30 days of age. In contrast, peak nerve and peak catecholamine responses to increased potassium did not significantly change with age. For a better understanding of how responsiveness increases with age, the fast Na+ and the Ca2+ currents were measured from isolated glomus cells of newborn and older rabbits, but the magnitude of the currents when normalized to membrane area was not significantly different between ages. We conclude that: (1) rabbit chemoreceptors mature in the newborn period (10-30 days) and part of this maturation is an increase in catecholamine secretion, (2) maturation of hypoxia transduction primarily occurs in steps prior to depolarization since potassium-evoked responses were not affected, and (3) an increase in the magnitude of glomus cell fast Na+ or Ca2+ currents is not a likely mechanism for the maturational change, but changes in the oxygen sensitivity of these currents cannot be excluded.

Motif trap: a rapid method to clone motifs that can target proteins to defined subcellular localisations

We have developed a rapid procedure termed Motif Trap (MT) to identify protein motifs that are able to target proteins to a distinct subcellular localisation in eukaryotic cells. By expressing random DNA fragments fused to green fluorescent protein (GFP), individual cells with the GFP localisation of interest are readily isolated allowing for the expressed DNA fragments to be cloned by RT-PCR. These can then be used to identify the corresponding full-length cDNAs. Using MT, we have identified patterns of GFP localisation which correspond to every major organelle and compartment. We have shown that MT is useful to identify new sequences that determine subcellular localisation as well as known targeting motifs.

[Neonatal colonization by Ureaplasma urealyticum and the development of bronchopulmonary dysplasia]

OBJECTIVE

The study purpose was to investigate the association between neonatal Ureaplasma urealyticum isolation, and bronchopulmonary dysplasia (BDP), in infants who had birth weights < 1,500 g, admitted in the Pediatric Intensive Care Unit, La Fe Hospital, Valencia, Spain.

METHODS

A cohort study was designed, since March 1996 until April 1998, with a cohort of exposed and no exposed, determined by isolation of U. urealyticum in tracheal aspirate or pharyngeal cultures. 137 infants were admitted to the intensive care unit in this period, and 101 of them were enrolled in this study.

RESULTS

U. urealyticum was isolated in 27 (26.7%) patients. The infants with U. urealyticum positive culture had a significantly lower gestational age (mean 28.1, SD 2.4 vs 29.2, SD 2.4; p = 0.048) than negative culture infants. BDP occurred in 30 infants (29.7%), and was significantly associated with decreasing gestational age (mean 26.9, SD 1.7 vs 29.7, SD 2.2; p < 0.001) and lower birth weight (mean 965.8, SD 166.7 vs 1121.4, SD 232.1; p < 0.001). However, after correction for gestational age by logistic regression analysis, DBP was significantly related to decreasing gestational age, but not to the presence of a positive U. urealyticum culture. In the cohort of U. urealyticum positive infants, BPD occurred in 9 (33%) vs 21 (28%) in the not colonized cohort. The odds ratio associated with colonization was 1.3 (CI 95% 0.5-3.2; p = 0.63).

CONCLUSIONS

BPD was significantly associated with decreasing gestational age, independently of birth weight and U. urealyticum colonization.