Diagnostic Value of Oral Provocation Tests in Drug Hypersensitivity Reactions Induced by Nonsteroidal Anti-Inflammatory Drugs and Paracetamol

Oral drug provocation tests (DPT) are the basic diagnostic tool for the detection of hypersensitivity to non-opioid analgesics and for selecting a safe alternative for a patient. They are of great practical importance due to their common use, but the data on the follow-up of patients after negative DPT are still very scarce. We examined the further fate of 164 such adult patients after negative NSAID or paracetamol tests and analyzed which excipients in the studied drugs they could be exposed to after the diagnostic workup. A structured medical interview was performed 32.9 months (mean) after the provocation tests. Of the 164 patients, 131 (79.9%) retook the tested drug and 12 developed another hypersensitivity reaction, giving the estimated negative predictive value of 90.8%. These reactions were induced by acetylsalicylic acid, paracetamol, meloxicam, and diclofenac, and were clinically similar to the initial ones (most commonly urticaria and angioedema). There are 93 generics of these drugs on the local market, containing a total of 33 excipients for which hypersensitivity reactions have been reported. All available generics contain such excipients. Thirty-one patients (20.1%) did not take the previously tested drug again, most often because it was not needed or because they were afraid of another reaction. DPT with analgesics has a high diagnostic performance. A minority of patients had relapsed after reexposure. One of the underestimated reasons for this may be drug excipients provoking a reaction, so it is advisable to use exactly the same medical product that has been negatively tested. Many patients avoid reexposure to a given drug, despite negative tests, therefore very reliable patient education in connection with DPT is highly needed.

ODP109 PARATHYROID HORMONE AND 25 OH VITAMINA D IN PREGNANCY: DATA FROM AN ARGENTINEAN COHORT SUPPORTING SUPPLEMENTATION

 

Vitamin D (Vit D) deficiency has become a global health care issue, as it affects a great number of women during pregnancy and lactation. Vit D levels are critical during pregnancy, being the mother the only source of them for the developing fetus; an enzymatic system for conversion of 25OH VitD into 1-25(OH) 2 VitD is present in the placenta, thus reinforcing the importance of VitD during gestation. VitD deficiency has been associated with obstetric complications and adverse outcomes in offspring, affecting skeletal, immunological and respiratory systems. It is known that prenatal supplements available do not contain enough VitD to fulfil requirements. It is generally accepted that elevated PTH is an indicator of VitD deficiency, and Hysaj O et al (2021) showed that 25OH VitD is a statistically significant determinant of PTH levels in early and late pregnancy.

Aim

To evaluateVitD status and its relationship to parathyroid hormone (PTH) in a cohort of pregnant women representative of multiple Argentinian regions.

Subjects and Methods

Data from samples of 423 pregnant women in 1st and 2nd trimester were collected between 2016 and 2021. VitD was measured in different platforms: DiaSorin Liaison CLIA (n=184), Roche COBAS ECLIA (n=166), Abbott ARCHITECT CMIA (n=33), Biomérieux VIDAS ELFA (n=18) and Siemens CENTAUR CLIA (n=16). PTH (ng/L) was measured in 162 samples by SIEMENS IMMULITE CLIA and Roche COBAS ECLIA. As VitD is light-exposure dependent, we considered warm and high light-exposure season period from December to March and cold and low light season from April to September. VITD (ng/L) levels were classified as Deficient (<20), Insufficient (between 21 and 29) and Sufficient (>30) (Endocrine Society, 2014).

Results

From 423 data collected, 102 were excluded because of lacking information on VitD supplementation. From the remaining non supplemented 321 samples, 48% resulted insufficient, 30% deficient and 22% sufficient for VitD (groups comparison: p< 0. 05, Kruskal Wallis-Dunn test). The seasonal period and pregnancy trimester distributions didn't show significant differences. Similar results of VitD insufficiency were found in the major used platforms, regardless the seasonal period considered. PTH results expressed as median and interquartile range were (ng/L): 32. 0 (13.7-169. 0) in Deficient pregnancies (N=92), 23.7(13.3-88. 0) in Insufficient (n=50) and 18.7 (9.8-55.7) in Sufficient (n=20).

Conclusions

This study shows VitD inadequate levels in 78% in non-supplemented pregnancies, regardless season or measurement platform. Relative elevated levels of PTH were associated to pregnancies with VitD deficiency, evidenciating a regulatory role according to published data. To improve VitD status during pregnancy it would be advisable to pose new strategies for prenatal supplements developed by a multidisciplinary professional team.

Presentation: No date and time listed

Determination of Zearalenone in Cereal Grains, Animal Feed, and Feed Ingredients Using Immunoaffinity Column Chromatography and Liquid Chromatography: Interlaboratory Study

A method using immunoaffinity column chromatography (IAC) and liquid chromatography (LC) for determination of zearalenone in cereal grains, animal feed, and feed ingredients was collaboratively studied. The test portion is extracted by shaking with acetonitrilewater (90 + 10, v/v) and sodium chloride. The extract is diluted and applied to an immunoaffinity column, the column is washed with water or phosphatebuffered saline or methanolwater (30 + 70, v/v), and zearalenone is eluted with methanol. The eluate is evaporated, the residue is dissolved in mobile phase and analyzed by reversed-phase LC with fluorescence detection. The presence of zearalenone can be confirmed using an alternate excitation wavelength or diode array detection. Twenty samples were sent to 13 collaborators (8 in Europe, 2 in the United States, one in Japan, one in Uruguay, and one in Canada). Eighteen samples of naturally contaminated corn, barley, wheat, dried distillers grains, swine feed, and dairy feed were analyzed as blind duplicates, along with blank corn and wheat samples. The analyses were done in 2 sample sets with inclusion of a spiked wheat control sample (0.1 mg/kg) in each set. Spiked samples recoveries were 89116, and for the 18 naturally contaminated samples, RSDr values (within-laboratory repeatability) ranged from 6.67 to 12.1, RSDR values (among-laboratory reproducibility) ranged from 12.5 to 19.7, and HorRat values ranged from 0.61 to 0.90.

Environmental factors driving the occurrence of the invasive cyanobacterium Sphaerospermopsis aphanizomenoides (Nostocales) in temperate lakes

Cyanobacterial blooms are an increasing threat worldwide. Invasions of certain cyanobacterial species, mainly towards higher latitudes, add to this concern as they enrich the pool of potential bloom-formers in the invaded region. Among the numerous causes of this escalating process, climate warming is commonly considered the most crucial factor, but empirical studies of this issue are lacking. The aim of our study was to identify physical, chemical and biological factors related to the occurrence of an invasive cyanobacterium at the northern border of its putative current range, and thus enabling its expansion. This study focuses on the relatively little studied species Sphaerospermopsis aphanizomenoides (Nostocales, Cyanobacteria; synonyms: Aphanizomenon aphanizomenoides, Anabaena aphanizomenoides), which is predicted to become one of the main nuisance species of the future. Forty-nine freshwater lakes located between latitudes 51° and 55°N were examined for the presence of S. aphanizomenoides, and environmental factors that could drive its occurrence were studied simultaneously. To identify factors correlated with the presence of the species, principal component analysis (PCA) and Mann-Whitney U test were performed. Water temperature did not differentiate lakes with or without S. aphanizomenoides, however the study was conducted in a particularly hot summer. Total phosphorus concentration was identified as the primary driving factor of the occurrence of S. aphanizomenoides. The species grew in poor light conditions and high phytoplankton biomass, mainly in shallow lakes. As shown by detrended correspondence analysis (DCA), the species accompanied shade tolerant, eutrophic species of native and invasive cyanobacteria as well as eukaryotic algae. Our results indicate that eutrophication may be the primary factor enabling the increasing occurrence of S. aphanizomenoides in temperate environments, and suggest that this process may stimulate expansion of cyanobacterial species towards high latitudes.

Multiscale Simulations of the RF Diode Sputtering of Copper

The morphology and microstructure of RF diode sputter deposited materials is a complicated function of many parameters of the reactor operating conditions. Using a combination of computational fluid dynamics (CFD), RF plasma, molecular dynamics (MD) sputter, and direct simulation Monte Carlo (DSMC) transport models, a multiscale approach has been used to analyze the RF diode sputtering of copper. The CFD model predicts the velocity and pressure distribution of the working gas flows in the deposition chamber. The plasma model uses these CFD results to compute ion energies and fluxes at the target and substrate. The MD model of sputtering is used to determine the initial energy distribution of sputtered atoms and reflected neutral working gas atoms and both of their angular distributions. A DSMC transport model then deduces the target atom deposition efficiency, the spatial distribution of the film thickness, the target and reflected neutral atoms energy and impact angle distributions given reactor operating input conditions such as background pressure, temperature, gas type, together with the reactor geometry. These results can then be used in atomistic growth models to begin a systematic evaluation of surface morphology, nanoscale structure, and defects dependences upon the reactor design and its operating conditions.

A Novel Phospholipid Derivative of Indomethacin, DP-155 [Mixture of 1-Steroyl and 1-Palmitoyl-2-{6-[1-(p-chlorobenzoyl)-5-methoxy-2-methyl-3-indolyl acetamido]hexanoyl}-sn-glycero-3-phosophatidyl Choline], Shows Superior Safety and Similar Efficacy in Reducing Brain Amyloid β in an Alzheimer's Disease Model

Indomethacin has been suggested for the treatment of Alzheimer's disease (AD), but its use is limited by gastrointestinal and renal toxicity. To overcome this limitation, D-Pharm Ltd. (Rehovot, Israel) developed DP-155 (mixture of 1-steroyl and 1-palmitoyl-2-{6-[1-(p-chlorobenzoyl)-5-methoxy-2-methyl-3-indolyl acetamido] hexanoyl}-Sn-glycero-3-phosophatidyl [corrected] choline), a lecithin derivative of indomethacin. Safety was tested by daily oral administration of DP-155 or indomethacin to rats in a dose range of 0.007 to 0.28 mmol/kg. The prevalence of gastrointestinal ulceration was significantly lower (10-fold) for DP-155 than for indomethacin, and the ulcerations were delayed. Signs of renal toxicity, namely reduced urine output and increased urine N-acetyl glycosaminidase to creatinine ratio, were 5-fold lower for DP-155. Indomethacin, but not an equimolar dose of DP-155, reduced urine bicyclo-prostaglandin E(2). An equimolar oral dose of DP-155 or indomethacin, administered every 4 h for 3 days, was equally efficacious in reducing the levels of Abeta42 in the brains of Tg2576 mice. Indomethacin was the principal metabolite of DP-155 in the serum. After DP-155 oral administration, indomethacin's half-life in the serum and the brain was 22 and 93 h, respectively, compared with 10 and 24 h following indomethacin oral administration. The brain to serum ratio was 3.5 times higher for DP-155 than indomethacin. This finding explains the efficacy of DP-155 in reducing Abeta42 brain levels, despite the low systemic blood concentrations of indomethacin derived from DP-155. In conclusion, compared with indomethacin, DP-155 has significantly lower toxicity in the gut and kidney while maintaining similar efficacy to indomethacin in lowering Abeta42 in the brains of Tg2576 mice. This superior safety profile highlights DP-155's potential as an improved indomethacin-based therapy for AD.

BRCA1-positive breast cancers in young women from Poland

We identified 4316 unselected incident cases of early-onset breast cancers (<51 ears of age at diagnosis) in 18 Polish hospitals between 1996 and 2003. We were able to obtain a blood sample for DNA analysis from 3472 of these (80.4%). All cases were tested for the presence of three founder mutations in BRCA1. The proportion of cases with a BRCA1 mutation was 5.7%. The hereditary proportions were higher than this for women with breast cancer diagnosed before age 40 (9%), for women with cancer of medullary or atypical medullary histology (28%), for those with bilateral cancer (29%) or with a family history of breast or ovarian cancer (13%). It is reasonable to offer genetic testing to women with early-onset breast cancer in Poland.

Response of F344 rats to inhalation of subclinical levels of sarin: exploring potential causes of Gulf War illness

Subclinical, repeated exposures of F344 rats to sarin resulted in brain alterations in densities of chlonergic receptor subtypes that may be associated with memory loss and cognitive dysfunction. The exposures also depressed the immune system. The rat appears to be a good model for studying the effects of subclinical exposure to a nerve gas.

Molecular mechanisms of fever and endogenous antipyresis

This review summarizes recent studies on endogenous antipyretic mechanisms. Fever is the result of a balance between pyrogenic and cryogenic cytokines and hormones. Although there is considerable evidence that fever evolved as a host defense response, it is important that the rise in body temperature not be too high. Many endogenous cryogens or antipyretics that limit the rise in body temperature have been identified during the last 25 years. These include alpha-MSH, arginine vasopressin, glucocorticoids, TNF (under certain circumstances), and IL-10. Most recently, evidence has accumulated that cytochrome P-450 (P-450), part of the alternative pathway for arachidonic acid metabolism, plays an important role in reduction of fever and inflammation. Supporting a role for P-450 in endogenous antipyresis and antiinflammation includes evidence that (1) inducers of P-450 reduce fever, (2) inhibitors of P-450 cause a larger fever, (3) and P-450 arachidonic acid metabolites reduce fever.

Effect of heat stress on LPS-induced febrile response in D-galactosamine-sensitized rats

We have previously reported that heat conditioning augments lipopolysaccharide (LPS)-induced fever in rats, which is accompanied by an accumulation of heat shock protein (HSP) in the liver and the reduction of the plasma level of tumor necrosis factor (TNF-alpha) (Kluger MJ, Rudolph K, Soszynski D, Conn CA, Leon LR, Kozak W, Wallen ES, and Moseley PL. Am J Physiol Regulatory Integrative Comp Physiol 273: R858-R863, 1997). In the present study we have tested whether inhibition of protein synthesis in the liver can reduce the effect of this heat conditioning on the LPS-induced febrile response in the rat. D-galactosamine (D-gal) was used to selectively inhibit liver protein synthesis. D-gal (500 mg/kg) or PBS as control was administered intraperitoneally 1 h before heat stress. LPS (50 microg/kg ip) was injected 24 h post-heat exposure. Treatment with D-gal blunted the febrile response to LPS. Moreover, heat-conditioned rats treated first with D-gal and subsequently with LPS demonstrated a profound fall in core temperature 10--18 h post-LPS. A significant increase of serum TNF-alpha accompanied this effect of D-gal on fever. Heat-conditioned animals receiving D-gal showed an inhibition in inducible HSP-70 in the liver. These data support the role of hepatic function in modulating the febrile response to LPS.

Role of cytochrome P-450 in endogenous antipyresis

In previous reports, we (15, 18) and others (29) demonstrated data showing that various inhibitors of cytochrome P-450/epoxygenase augment fever in rats and mice, indicating that the enzyme may be involved in endogenous antipyresis. The aim of this study was to further test the hypothesis that the P-450-dependent epoxygenase pathway of arachidonic acid is part of the homeostatic system to control the height of fever. Sprague-Dawley rats were implanted with biotelemeters to monitor body temperature. Fever was induced by intraperitoneal injection of lipopolysaccharide (LPS; 80 microg/kg). We demonstrate that intraperitoneal administration of P-450 inducers (bezafibrate and dehydroepiandrosterone, 10 and 100 mg/kg) before LPS reduced fever in rats in a dose-dependent manner. In complementary experiments, rats were implanted with brain cannulas in addition to the biotelemeters. Various isomers of epoxyeicosanoids were administered into the lateral ventricle at doses of 0.01 to 10 microg/rat to test their influence on LPS-induced fever in rats. Four of five isomers were antipyretic in a dose-dependent manner. The most potent antipyretic isomers were 11, 12-epoxyeicosatrienoic acid (EET) followed by 14,15-EET, 8,9-EET, and 12(R) hydroxyeicosatetraenoic acid. These data support the hypothesis that the cytochrome P-450/epoxygenase pathway of arachidonate metabolism is part of the endogenous antipyretic system.

Acute and chronic nicotine exposures modulate the immune system through different pathways

We have previously shown that T cells from rats exposed chronically to cigarette smoke or nicotine (NT) exhibit T cell anergy and decreased proliferation to T cell mitogens. Effects of chronic NT on T cell function persist for at least 2 weeks after the termination of NT treatment. Moreover, these effects of NT are causally related to the decreased Ca(2+) response to T cell receptor (TCR) ligation and constitutive activation of protein tyrosine kinase (PTK) and phospholipase C (PLC)-gamma1 activities. Acute NT treatment also suppresses the Con A-induced T cell proliferation; however, it is not known whether the mechanism(s) by which acute and chronic NT treatments inhibit T cell proliferation are identical. To evaluate this question, LEW rats were acutely treated with NT (1 mg/kg body wt) for 1, 2, or 24 h by an ip injection or implanted with constant-release miniosmotic pumps containing saline or NT (1 mg/kg body wt/day) for a 3-week chronic exposure. Inhibition of Con A-induced proliferation of peripheral blood cells (PBC) by both acute and chronic treatments was reversed by the inhibitor of nicotinic acetylcholine receptors, mecamylamine (MEC), indicating that these receptors are required for T cell proliferation. However, the effect of acute NT on the Con A response was short lived (i.e., observed at 1 and 2 h but not at 24 h after NT administration) and was seen in PBC but not in spleen cells. Unlike the chronic treatment, acute NT administration neither suppressed significantly the TCR-mediated [Ca(2+)](i) response nor did it cause the constitutive activation of PTK and PLC-gamma1 activities in blood lymphocytes. Acute, but not chronic, NT administration increased the plasma corticosterone concentration, and this increase was also inhibited by MEC. Moreover, adrenalectomy abrogated the acute but not chronic NT effects on the Con A response. Thus, the acute and chronic effects of NT on T lymphocytes are mechanistically distinct phenomena. Whereas chronic administration of NT causes T cell anergy, acute effects are primarily mediated via the activation of the hypothalamus-pituitary-adrenal axis.

Beta-adrenergic receptor subtype effects on stress fever and thermoregulation

Exposure to psychological stress increases body temperature (Tb). This stress fever may be immunologically beneficial in some patient populations but detrimental in others (e.g., HIV-infected individuals). For this reason, it is desirable to determine pharmacological methods of preventing stress fever. In rats, stress fever is modeled by exposure to a novel environment or 'open field.' The beta-adrenergic antagonists, nadolol and propranolol, block this stress fever. Neither of these beta-antagonists discriminates between subtypes of beta-receptors. The purpose of this study was to determine the relative contribution of the different beta-receptor types to stress fever using beta1-, beta2-, and beta3-receptor subtype selective antagonists (atenolol [beta1], ICI-118551 [beta2], and SR 59230A [beta3]) and agonists (dobutamine [beta1], salbutamol [beta2], and BRL 37344 [beta3]) on the Tb of rats. Tb was measured with a biotelemetry system. Our data suggest that central nervous system beta-receptor blockade with subtype-selective antagonists prevents the stress-induced rise in Tb; however, the beta3-antagonist was effective only at doses that produced hypothermia in a non-stressed control group. The stress-induced fever was mimicked by central nervous system administration of the selective beta2-agonist, salbutamol, and the beta3-agonist, BRL 37344. We hypothesize that the blockade of stress-induced fever by beta-blockers may be due to the sedative actions of these drugs.

Inhibitors of alternative pathways of arachidonate metabolism differentially affect fever in mice

Inhibitors of cyclooxygenases prevent fever. The purpose of this study was to test the hypothesis that selective and dual inhibitors of the other enzyme systems of arachidonic acid oxygenation (i.e., lipoxygenase and epoxygenase) affect the time course or magnitude of fever in mice. Swiss Webster mice kept at 30 degreesC ambient temperature were implanted with biotelemeters to monitor body temperature. Fever was induced by intraperitoneal injection of lipopolysaccharide at doses from 10 micrograms/kg to 2.5 mg/kg. Phenidone (20-30 mg/kg ip), a dual lipoxygenase and cyclooxygenase inhibitor, prevented fever in these mice, but esculetin (1-10 mg/kg ip), a selective inhibitor of lipoxygenases, did not affect fever. Intramuscular injection of nordihydroguaiaretic acid (10-20 mg/kg), a dual lipoxygenase and epoxygenase inhibitor, as well as SKF-525A (5 mg/kg ip) and clotrimazole (20 mg/kg im), inhibitors of the cytochrome P-450/epoxygenase pathway, augmented fever in mice. Indomethacin (5 mg/kg ip), an inhibitor of cyclooxygenase, suppressed the exacerbation of fever due to clotrimazole, suggesting that the epoxygenase inhibitor-induced potentiation of fever in mice is a prostaglandin-mediated effect. From this study, we hypothesize that the cytochrome P-450/epoxygenase branch of the arachidonate cascade is involved in antipyresis and in controlling the upper limit of fever.

Knowledge coupling: implementing outcomes measurement through the disciplined and routine control of inputs

The successful implementation of outcomes measurement is jeopardized by its application within systems that do not control inputs. This systemic flaw within health care can be corrected by placing critical knowledge that is now in the minds of individual practitioners into computer-based knowledge coupling tools that can (1) track and control the inputs to the system in a disciplined and routine manner and (2) process information without error or bias. Outcomes then become a natural by-product of what amounts to a paradigm shift in the conceptualization and implementation of health care.

The effect of chemo- and chemoimmunotherapy on the presence of circulating melanoma cells in peripheral blood. Preliminary results

Reverse transcription and polymerase chain reaction (RT/PCR) with primers specific for tyrosinase allow for a new method of early detection of individual melanoma cells in peripheral blood. Using this test the effect of chemo- and chemoimmunotherapy on the spread of early micrometastatic cancer cells has been evaluated. No significant correlations have been found between RT/PCR results on the one hand and stage of disease, a kind of the therapy protocol used and usage of the therapy as an adjuvant or palliative on the other hand. Thus, although the RT/PCR test for detection of circulating individual melanoma cells might help in identification of minimal residual disease in some patients, it has no application for routine staging of more advanced disease and in monitoring the response to therapy.

The effect of chemo- and chemoimmunotherapy on the presence of circulating melanoma cells in peripheral blood. Preliminary results

Reverse transcription and polymerase chain reaction (RT/PCR) with primers specific for tyrosinase allow for a new method of early detection of individual melanoma cells in peripheral blood. Using this test the effect of chemo- and chemoimmunotherapy on the spread of early micrometastatic cancer cells has been evaluated. No significant correlations have been found between RT/PCR results on the one hand and stage of disease, a kind of the therapy protocol used and usage of the therapy as an adjuvant or palliative on the other hand. Thus, although the RT/PCR test for detection of circulating individual melanoma cells might help in identification of minimal residual disease in some patients, it has no application for routine staging of more advanced disease and in monitoring the response to therapy.

[Preliminary evaluation of a method for detection of individual malignant melanoma cells in peripheral blood while monitoring the course of the malignancy and its treatment]

Using reverse transcription and polymerase chain reaction (PCR) with primers specific for tyrosinase the individual melanoma cells were detected in peripheral blood of patients in different stages of disease, after excision of primary lesion and prior and after chemotherapy. No relation between stage of disease (including situations with overt generalized spread of melanoma) and probability of positive PCR reaction detecting transcript for tyrosinase gene was found. Many patients in III and IV stages were negative for prolonged periods. Therefore, this method cannot be used for monitoring of all patients, because many of them are negative prior as well as after chemotherapy. With regard to the effects of therapy, the patients differed one to another and although some persons positive prior treatment became negative thereafter, a similar number of initially negative patients became positive after treatment.

Isolation and characterization by cell density adjustment of a PC12 pheochromocytoma variant with altered Ca2+ homeostasis

Rat PC12 pheochromocytoma cells loaded with the fluorescent Ca2+ dye fluo-3 or indo-1 and scanned fluorimetrically on a cell sorter apparatus showed a rapid cell density-dependent increase in free cytosolic calcium concentration [Ca2+]i when maintained in suspension cultures. Cell adhesion, measured under a defined set of conditions, was low when cells were seeded at 1.5 x 10(4) cells/ml but reached maximal levels after addition of A23187 calcium ionophore. A six to sevenfold increase in cell density mimicked the effect of the ionophore. Densities above 2 x 10(6) cells/ml caused a decrease in cell adhesion, which was further reduced by the addition of A23187. BAPTA, AM (1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid) and nifedipine (10 microM each), partially inhibited cell attachment (34% and 44% reduction), but at 0.25 microM and 1 microM, respectively, they enhanced attachment (46% and 67% increase). The data suggest that a certain permissive level of [Ca2+]i, attained by either increasing cell density or by the presence of a calcium ionophore, is sufficient for maximal cell adhesion. Above the permissive level, manipulation of [Ca2+]i either by altering cell density or by the addition of calcium blocking agents in high concentrations results in a significant reduction in cell adhesion. Based on these observations, we were able to isolate a biochemically and morphologically distinct cell population. The variant, designated PC12ds (density selected), differed substantially from the original cells. Most notable was a relatively lower content of free [Ca2+]i in the PC12ds cells, as independently assayed by using fluo-3 and indo-1 dyes. In addition, the variant cells exhibited a significantly diminished rate of 45Ca2+ uptake, most likely due to less efficient L-type voltage-dependent calcium (VDC) channels. Addition of several calcium channels agonists and antagonists suggested that PC12ds cells contained relatively more N-type VDC channels, possibly indicating a shift to a neuronal phenotype.

Intracellular calcium levels regulate the actions of nerve growth factor on calcium uptake in PC12 cells

The uptake of divalent cations and the intracellular concentration of calcium in PC12 cells were studied by flow cytometric analysis using the calcium-sensitive dye, Fluo-3, under a variety of conditions. In particular the actions of nerve growth factor were analyzed. The data show that nerve growth factor stimulates the uptake of divalent cations and increases the intracellular calcium levels of cells attached to collagen-coated plates. The data further indicate that nerve growth factor-dependent increases in the uptake of divalent cations become less pronounced as the intracellular concentration of calcium increases. Intracellular calcium levels increase upon detachment of the cells from the plates and also with increasing cell density. Studies on the uptake of 45calcium confirmed the influence of intracellular calcium levels on nerve growth factor-stimulated calcium uptake. Thus, the effect of nerve growth factor on the uptake of divalent cations is dependent on the calcium levels in the cells, perhaps explaining why previous studies in this field have provided inconsistent results.

[Contamination of human milk with nitrates and nitrites]

Human milk nitrates and nitrites were assayed colorimetrically. Colostrum samples were collected on the 3rd postpartum day from 59 women inhabiting Puławy region and being potentially exposed to nitrogen compounds emitted from the industrial sources. Thirty five Lublin inhabitants serving as a control group were matched in age, parity and duration of pregnancy. Geometric mean value of nitrates and nitrites concentration in the human milk being 2.83 mg/L and 0.46 mg/L, respectively were higher in the examined group than those in the control group /2.76 mg/L and 0.32 mg/L/ but difference was statistically insignificant. Ratio of nitrates and nitrites in the examined samples was 7.38 on the average and the concentration of those compounds was related statistically significantly /p less than 0.001/. The average daily intake of nitrates and nitrites by the breast-fed neonates was 0.12 mg/kg body weight and 0.02 mg/kg body weight, respectively. These values did not exceed corresponding ADI recommended by the Joint Expert Committee of FAO/WHO in none case. Significantly positive correlation of examined mothers' age and parity with nitrates content in their colostrum was seen. In view of the obtained results is may be assumed that the examined colostrum samples contain low amounts of both nitrates and nitrites.

Cefazolin-induced pseudomembranous colitis resulting in perforation of the sigmoid colon

The seventh case of probable cefazolin-induced pseudomembranous colitis is reported. Perforation of the colon necessitated sigmoid resection. The postoperative course was protracted, and illustrates the difficulty of managing advanced pseudomembranous colitis when the oral route of antibiotic administration is not available. Although rare, pseudomembranous colitis related to cefazolin administration is a potentially fatal complication. The routine use of prophylactic antibiotics must be weighed against this possibility.